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Mil-Std-882E Safety Analysis

Functional Hazard Analysis

In this full-length (40-minute) session, The Safety Artisan looks at Functional Hazard Analysis, or FHA, which is Task 208 in Mil-Std-882E. FHA analyses software, complex electronic hardware, and human interactions. We explore the aim, description, and contracting requirements of this Task, and provide extensive commentary on it. (We refer to other lessons for special techniques for software safety and Human Factors.)

This is the seven-minute demo; the full version is 40 minutes long.

Topics: Functional Hazard Analysis

  • Task 208 Purpose;
  • Task Description;
  • Update & Reporting
  • Contracting; and
  • Commentary.

Transcript: Functional Hazard Analysis

Click here for the Transcript

Introduction

Hello, everyone, and welcome to the Safety Artisan; Home of Safety Engineering Training. I’m Simon and today we’re going to be looking at how you analyse the safety of functions of complex hardware and software. We’ll see what that’s all about in just a second.

Functional Hazard Analysis

I’m just going to get to the right page. This, as you can see, functional hazard analysis is Task 208 in Mil. Standard 882E.

Topics for this Session

What we’ve got for today: we have three slides on the purpose of functional hazard analysis, and these are all taken from the standard. We’ve got six slides of task description. That’s the text from the standard plus we’ve got two tables that show you how it’s done from another part of the standard, not from Task 208. Then we’ve got update and recording, another two slides. Contracting, two slides. And five slides of commentary, which again include a couple of tables to illustrate what we’re talking about.

Functional Purpose HA #1

What we’re going to talk about is, as I say, functional hazard analysis. So, first of all, what’s the purpose of it? And in classic 882 style, Task 208 is to perform this functional hazard analysis on a system or subsystem or more than one. Again, as with all the other tasks, it’s used to identify and classify system functions and the safety consequences of functional failure or malfunction. In other words, hazards.

Now, I should point out at this stage that the standard is focused on malfunctions of the system. The truth is in the real world, that lots of software-intensive systems have been involved in accidents that have killed lots of people, even when they’re functioning as intended. That’s one of the short-sightedness of this Mil. Standard is that it focuses on failure. The idea that if something is performing as specified, that either the specification might be wrong or there might be some disconnect between what the system is doing and what the human expects – The way the standard is written just doesn’t recognize that. So, it’s not very good in that respect. However, bearing that in mind, let’s carry on with looking at the task.

Functional HA Purpose #2

We’re going to look at these consequences in terms of severity – severity only, we’ll come back to that – for the purpose of identifying what they call safety-critical functions, safety-critical items, safety-related functions, and safety-related items. And a quick word on that, I hate the term ‘safety-critical’ because it suggests a sort of binary “Either it’s safety-critical. Yes. Or it’s not safety-critical. No.” And lots of people take that to mean if it’s “safety-critical, no,” then it’s got nothing to do with safety. They don’t recognize that there’s a sort of a sliding scale between maximum safety criticality and none whatsoever. And that’s led to a lot of bad thinking and bad behaviour over the years where people do everything they can to pretend that something isn’t safety-related by saying, “Oh, it’s not safety-critical, therefore we don’t have to do anything.” And that kind of laziness kills people is the short answer.

Anyway, moving on. So, we’ve got these SCFs, SCIs, SRFs, SRIs and they’re supposed to be allocated or mapped to a system design architecture. The presumption in this – the assumption in this task is that we’re doing early – We’ll see that later – and that system design, system architecture, is still up for grabs. We can still influence it. Often that is not the case these days. This standard was written many years ago when the military used to buy loads of bespoke equipment and have it all developed from new. That doesn’t happen anymore so much in the military and it certainly doesn’t happen in many other walks of life – But we’ll talk about how you deal with the realities later. And they’re allocating these functions and these items of interest to hardware, software and human interfaces. And I should point out, when we’re talking about all that, all these things are complex. Software is complex, human is complex, and we’re talking about complex hardware. So, we’re talking about components where you can’t just say, “Oh, it’s got a reliability of X, and that’s how often it goes wrong” because those type of simple components that are only really subject to random failure, that’s not what we’re talking about here. We’re talking about complex stuff where we’re talking about systematic failure dominating over random, simple hardware failure. So, that’s the focus of this task and what we’re talking about. That’s not explained in the standard, but that’s what’s going on.

Functional HA Purpose #3

Now, our third slide on purpose; so we use the FHA to identify consequences of malfunction or functional failure, lack of function. As I said just now, we need to do this as early as possible in the systems engineering process to enable us to influence the design. Of course, this is assuming that there is a systems engineering process – that’s not always the case. We’ll talk about that at the end as well. And we’re going to identify and document these functions and items and allocate and it says partition them in the software design architecture. When we say partition, that’s jargon for separate them into independent functions. We’ll see the value of that later on. Then we’re going to identify requirements and constraints to put on the design team to say, “To achieve this allocation in this partitioning, this is what you must do and this is what you must not do”. So again, the assumption is we’re doing this early. There’s a significant amount of bespoke design yet to be done.

Task Description (T208) #1

Moving on to task description. It says the contractor, but whoever’s doing the analysis has to perform and document the FHA, to analyse those functions, as it says, with the proposed design. I talked about that already so we’ll move on.

It’s got to be based on the best available data, including mishap data. So, accident/incident data, if you can get it from similar systems and lessons learned. As I always say in these sessions, this is hard to do, but it’s really, really valuable so do put some effort into trying to get hold of some data or look at previous systems or similar systems. We’re looking at inputs, outputs, interfaces and the consequences of failure. So, if you can get historical data or you can analyse a previous system or a similar system, then do so. It will ultimately save you an awful lot of money and heartache if you can do that early on. It really is worth the effort.

Task Description (T208) #2

At a minimum, we’ve got to identify and evaluate functions and to do that, we need to decompose the system. So, imagine we’ve got this great big system. We’ve got to break it down into subsystems of major components. We’ve got to describe what each subsystem and major component does, its function or its intended function. Then we need a functional description of interfaces and thinking about what connects to what and the functional ins and outs. I guess pretty obvious stuff  – needs to be done.

Task Description (T208) #3

And then we also need to think about hazards associated with, first of all, loss of function. So, no function when we need it. Now, we have degraded functional malfunction and sort of functioning out of time or out of sequence. So, we’ve got different kinds of malfunctions. What we don’t have here is function when not required. So, the system goes active for some reason and does something when it’s not meant to. Now, if we add that third base and we’ve got a functional failure analysis.

Essentially here, we’re talking about a functional failure analysis, maybe something a bit more sophisticated, like a HAZOP. And the HAZOP is more sophisticated because instead of just those three things that can go wrong, we think about we’ve got lots of guide words to help us think about ‘out of time, out of sequence’. So, too early, too late, before intended, after intended, whatever it might be. And there are there variations on HAZOP called computer HAZOP, or CHAZOP, where people have come up with different keywords, different prompt words, to help you think about software in data-intensive systems. So, that’s a possible technique to use here.

And then when we’re thinking about these hazards that might be generated by malfunction, or functional failure in its various forms, we need to think about, “What’s the next step in the mishap sequence? In the accident sequence? And what’s the final outcome of the accident sequence?” And that’s very important for software because software is intangible. It has no physical form. On its own, in isolation, software cannot possibly hurt anyone. So, you’ve got to look at how the software failure propagates through the system into the real world and how it could harm people. So, that’s a very important prompt that that last sentence in yellow there.

Task Description (T208) #4

And we carry on. We need to assess the risk with failure of a function subsystem or component. We’re going to do so using the standard 882 tables, tables one and two, and risk assessment codes in table three, unless we come up with our own tailored versions of those tables and that matrix and that’s all approved. In reality, most people don’t tailor this stuff. They should make it appropriate for the system, but they rarely do.

Table I and II

So just to remind us what we’re talking about, here’s table one and two. Table one is severity categories ranging from catastrophic, which could kill somebody – a catastrophic outcome – down to negligible, where we’re talking cuts and bruises – very, very, very minor injuries.

And then table two, probability levels. We’ve got everything from frequent down to eliminated – There’s no hazard at all because we’ve eliminated. It will never happen in the lifetime of the universe. So, it really is a zero probability. We’ve got frequent down to improbable and then in the standard, we’ve got a definition for these things in words, for a single item and also for a fleet or inventory of those items, assuming that there’s a large number of them. And that’s very useful. That helps us to think about how often something might go wrong per item and per fleet.

Table III

So, that’s tables one and two, we put them together, the severity and the probability to give us table three. As you can see, we’ve got probability down the left-hand side and at the bottom, if we’ve eliminated the hazard, then there is no severity. The hazard is completely eliminated. So, forget about that row. Then everything else we’ve got frequent down to improbable, probability. And we’ve got catastrophic down to negligible. Together those generate the risk assessment code, which is either high, serious, medium or low. That’s the way this standard defines things. Nothing is off-limits. Nothing is perfect except for elimination. We’ve just defined a level of risk and then you have to make up rules about how you will treat these levels of risk. The standard does some of that for you, but usually, you’ve got to work out depending on which jurisdiction you’re in legally, what you’re required to do about different levels of risk.

Now this table on its own, I’ll just mention, is not helpful in a British or Australian jurisdiction where we have to reduce or eliminate risks SOFARP. The table on its own won’t help you do that, because this is just an absolute level of risk. It’s not considering what you could have done to make it better. It’s just saying where we are. It’s a status report.

So, those are your tables one, two and three, as the standard describes them. That’s the overall method and we’re going to do what it says in Section four of the standard. In the main body of the standard, Section four talks about software and complex hardware and how we allocate these things.

Task Description (T208) #5

And then finally, I think on task description, an assessment of whether the functions identified are to be implemented in the design – sorry, of whether the functions are to be implemented in the design and map those functions into the components. And then it says functions allocated to software should be matched to the lowest level of technical design or configuration item. So, if you’ve got a software or hardware configuration item that is further subdivided into sub-items, then you need to go all the way down and see which items can contribute to that function and which can’t.

That’s an important labour-saving device, because if you’ve got  – you could have quite a large configuration item, but actually, only a tiny bit contributes to the hazard. So, that’s the only thing you need to worry about in theory. In reality, partitioning software is not as easy as the standard might suggest. However, if we can do a meaningful partition, then we could and should aim to have as little software safety-related as we possibly can. If nothing else, for cost in order to get the project in on time. So, the less criticality we have in our system, the better.

Task Description (T208) #6

So, we need to assess the software control category for each configuration item that’s been allocated a safety-significant software function (SSSF). Having assigned the SCC, we then have to work at the software criticality index for each of those functions and we’ll talk about how to do that at the end. Then from all of this work, we need to generate a list of requirements and constraints to include in the spec which, if they work, will eliminate the hazard or reduce the risk.

And the standard talks about that these could be in the form of fault tolerance, fault detection, fault isolation, fault annunciation or warning, or fault recovery. Now, this breakdown reveals – basically this is a reliability breakdown. So, in the world of reliability, we talk typically about fault tolerance, fault detection, warning, and recovery. Four things – I mean they split them down to five here. Now, software reliability is highly controversial. So really, this is a bit of a mismatch here. These reliability-based suggestions are not necessarily much use for software, or indeed for people sometimes. You may have to use other more typical software techniques to do this and in fact, the standard does point you to do that. But that’s for another session.

FHA Update & Records #1

So, we’ve done the FHA, or we’re doing the FHA. We’ve got to record it and we’ve got to update it when new information comes through. So, we’ve got to update the FHA as the design progresses or operational changes come in. We’ve got to have a system description of the physical and functional characteristics of the system and subsystems. And of course, for design complex items like software, context is everything. So, this is very important. Again, software in isolation cannot hurt anyone. You’ve got to have the context to understand what the implications might be. If we don’t have that, we’re stuffed pretty much. Then it goes on to say that when further documentation becomes available, more detail that needs to be supplied. So, don’t forget to ask for that in your contract and expect it as well and be ready to deal with it.

FHA Update & Records #2

 Moving on. When it comes to hazard analysis, method and techniques, we need to describe the method and the technique used for the analysis, what assumptions and what data was used in support of the analysis and this statement is pretty much in every single task so I’ll say no more. You’ve heard this before. Then again, analysis results need to be captured in the hazard tracking system and, as I’ve always said, usually the leading details, the top-level details, go in there has a tracking system. The rest of it goes into the hazard analysis report otherwise, you end up with a vast amount of data in your HTS and it becomes unwieldy and potentially useless.

Contracting #1

Contracting – Again, this is a pretty standard clause, or set of clauses, in a Mil. Standard 882 task. So, in our request for proposal and statement of work, we’ve got to ask for Task 208. We’ve got to point the analyst, the contractor, at what we want them to analyse particularly or maybe as a minimum. And what we don’t want to analyse, maybe because it’s been done elsewhere or it’s out of scope for this system.

We need to say what are data reporting requirements are considering Task 106, which is all about hazard tracking system or the hazard log or the risk register, whatever you want to call it. So, what data do we want? What format? What are the definitions, etc.? Because if you’re dealing with multiple contractors or you want data that is compatible with the rest of your inventory, then you’ve got to specify what you want. Otherwise, you’re going to get variability in your data and that’s going to make your life a whole lot harder downstream – Again, this is standard stuff.

And what are the applicable requirements, specifications and standards? Of course, this is an American standard so compliance with specifications, requirements and standards is all because that’s the American system.

Contracting #2

We need to supply the concept of operations, as I’ve said before, with a complex design. Especially software, context is everything. So, we need to know what we’re going to do with the system that the software is sat within. So, this system has got some functions, this is what we’re looking at in Task 208: What are those functions for? How do they to relate with the real world? How could we hurt people? And then if we got any other specific hazard management requirements. Maybe we’re using a special matrix because we’ve decided the standard matrix isn’t quite right for our system. Whatever we’re doing, if we’ve got special requirements that are not the norm for the vanilla standard, that we need to say what they are. Pretty straightforward stuff.

Commentary #1

We’re onto commentary, and I think we’ve got five slides of commentary today.

As it says, functional hazard analysis depends on systems engineering. So, if we don’t have good systems engineering, we’re unlikely to have good functional analysis. So, what do I mean by good systems engineering? I mean, that for the complete system – apart from things that we deliberately excluded for a good reason – but for the complete system we need or functions to be identified, we need those functions to be analysed and allocated correctly in accordance and rigorously and consistently. We need interface analysis, control, and we need the architecture of the design to be determined based on the higher-level requirements, all that work that we’ve done.

Now, if those things are not done or they’re incomplete, or they were done too late to influence the design architecture, then you’re going to have some compromised systems engineering. And these days, because we’re using lots of commercial off the shelf stuff, what you find is that your top-level design architecture is very often determined before you even start because you’ve decided you’re going to have an off the shelf this and you’re going to have a modified off the shelf that and you’re going to put them together in a particular way with a set of business rules, a concept of operations, that says this is how we’re going to use this stuff. And our new system interfaces with some existing stuff and we can’t modify the existing stuff.

So, that really limits what we can do with the design architecture. A lot of the big design decisions have already been taken before we even got started. Now, if that’s the case, then that needs to be recognized and dealt with. I’ve seen those things dealt with well. In other words, the systems engineering has been done recognizing those constraints, those things that that can’t be done. And I’ve seen it done badly in that figuratively speaking, the systems engineering team or the program manager, whoever has just given us a Gallic shrug and gone “Yeah, what the heck, who cares?” So, there’s this the two extremes that you can see.

Now, if the systems engineering is weak or incomplete, then you’re going to get a limited return on doing Task 208. Maybe there are some areas where you can do it on new areas, or maybe you’ve got a new interface that’s got to be worked up and created in order to get these things to talk to each other. Clearly, there is some mileage in doing that. You’re going to get some benefits from doing that in that area. But for the stuff that’s already been done, probably – Well, what what’s the point of doing systems engineering here? What does it achieve? So, maybe in those circumstances, it’s better – Well, in fact, I would say it’s essential to understand where systems engineering is still valid, where you are still going to get some results and where it isn’t. And maybe you just declare that scope; What’s in and out.

Or maybe you take a different approach. Maybe you go “OK, we’re dealing with a predominantly COTS system. We need a different way of dealing with this than the way the Mil. standard 882 assumes.” So, you’re going to have to do some heavy tailoring of the standard because 882 assumes that you’re determining all these requirements predesigned. If that’s not the case, then maybe 882 isn’t for you. Or maybe you just need to recognize you’re going to have to hack it about severely. Which in turn means you’ve got to know what you’re doing fundamentally. In which case the standard really is no longer fulfilling its role of guiding people.

Commentary #2

Moving on. Let’s assume that we are still going to do some Task 208. We’re going to determine some software criticality. We’re also going to determine some criticality for complex hardware. So, things whether it be software in complex electronics, so pre-programmed electronics, whatever that might be. First of all, as we said before, we’re going to determine the software control category and what that’s really saying is how much authority does the software have? And then secondly, we’re going to be looking at severity, which was table one. How severe is the worst hazard or risk that the software could contribute to? And these are illustrated in the next two slides. And we do a session or several sessions on software safety is coming soon. That will be elsewhere. I’m not going to go into massive detail here. I’m just giving you an overview of what the task requires.

Commentary #3: Software Control Categories 1-5

First of all, how do we determine software control category? So, there’s the table from the standard. We’ve got five levels of SCC.

At the top, we’ve got autonomous. Basically, the software does whatever it wants to and there’s no checks and balances.

Secondly, they’re semi-autonomous. The software is there’s one software system performing a function, but there are hardware interlocks and checks. And those hardware interlocks and checks, and whatever else that are not software, can work fast enough to prevent the accident happening. So, they can prevent harm. So, that’s semi-autonomous.

Then we’ve got redundant fault-tolerant where you’ve got an architecture typically with more than one channel, and maybe all channels are software controlled. Maybe there’s diversity in the software and there is some fault-tolerant architecture. Maybe a voting system or some monitoring system saying, “Well, Channel Three’s output is looking a bit dodgy” or “Something gone wrong with Channel two”. I’ll ignore the channel at fault, and I’ll take the good output from the channels that are still working and I’ll use that. So that’s that option. Very common.

Then we’ve got number four, which is influential. So, the software is displaying some information for a human to interpret and to accept or reject.

And then we’ve got five, which is no safety impact at all. Now, the problem is this: because it’s very easy to say, “The software just displays some information, it doesn’t do anything”. So, unless a human does something – so we don’t have to worry about the safety implications of that at all. Wrong! Because the human operator may be forced to rely on the software output by circumstances, there may not be time to do anything else. Or the human may not be able to work out what’s going on without using the software output. Or more typically, the humans have just got used to the software generating the correct information or even they interpret it incorrectly.

And a classic example of that was when the American warship, the USS Vincennes, shot down an airliner and killed three hundred people because the way the system was set up, the supposedly not safety-related radar system was displaying information not associated with the airliner, but associated with the with a military Iranian aircraft. And the crew got mixed up and shot down the airliner. So, that’s a risky one. Even though it’s down at number four, that doesn’t mean it’s without risk or without criticality.

Commentary #4

So, if we have the software control category, and that’s down the right-hand side – sorry down the left-hand side, one to five. And along the top, we have the severity category from catastrophic down to negligible. We can use that to determine the software criticality index, which varies from one most critical down to five least critical. It’s similar to the risk assessment code in the table three coloured matrix that I showed you earlier. So, we’ve made – the writers of the standard have made a determination for us based on some assessment that they’ve done saying, “Well, this is this is how we assess these different criticality levels”. Whether there is actually any real-world evidence supporting this assessment, I don’t know and I’m not sure anybody else does either. However, that’s the standard and that’s where we are.

Commentary #5

And so just to finish up on the commentary. Task 208 is focused on software engineering, also programmable electronics, complex hardware, but typically electronics with software functionality or logic functionality embedded within it. Now if all of that software, all that programmable electronic systems, if they’re all developed already, is there any point in doing Task 208? That’s the first step – it’s got to pass the “So what?” test.

Is it feasible to do 208 and expect to get benefits? If not, maybe you just do system and subsystem hazard analysis. That’s tasks 205 and 204, respectively. And we just look at the complex components and subsystems as a black box and say, “OK, what’s it meant to do? What are the interfaces?” Maybe that would be a better thing to do. Particularly bearing in mind that the software or the complex electronic system could be working perfectly well and we still get an accident because there’s been a misunderstanding of the output. Maybe it’s more beneficial to look at those interfaces and think about, “Well, in what scenarios could the human misunderstand? How do we how do we guard against that?”

It’s also worth saying that some particularly American software development standards, can work well with Mil. Standard 882 because they share a similar conceptual basis. For example, I’ve seen many, many times in the air world, the systems software system safety standard is 882 and the systems software standard is DO-178 (AKA ED12, it’s the same standard, just different labels). Now they work relatively well together because the concept underpinning 178 is very similar to 882. It’s American centric.

It’s all about, you put requirements on the software development and – this is sort of a cookbook approach – the standard assumes that if you use the right ingredients and you mix them up in the right way, then you’re going to get a good result. And that’s a similar sort of concept for 882 and the two work relatively well together, fairly consistently. Also because they’re both American, there’s a great focus on software testing. Certainly, in the earlier versions of DO-178, it’s exclusively focused on software testing. Things like source code analysis and other things – more modern techniques that have come in – they’re not recognized at all in earlier versions of 178 because they just weren’t around.

That focus on testing suits 882, because 882, generates lots of requirements and constraints which you need to test. What it’s not so good at is generating cases where you say, “Well if this goes wrong” or “If we’re at the edge of the envelope where we should be, let’s test for those edge of the envelope cases, let’s test that the software is working correctly when it’s outside of the operating envelope that it should be”. Now, that kind of thinking isn’t so strong in 882, nor in 178. So, there are some limitations there. Good practice, experienced practitioners will overcome those by adding in the smarts that the standards lack. But just to be aware, a standard is not smart. You’ve still got to know what you’re doing in order to get the most out of it.

So, maybe you’re buying software that’s predevelopment or that you’re using – you’re not in the States. You’ve got a European or an Asian Indian supplier or Japanese supplier or whatever. Maybe they’re not using American style techniques and standards. Is that – how well is that going to work with 882? Are they compatible? They might be, but maybe they’re not. So, that requires some thought. If they’re not obviously compatible, then what do you need to do to make that translation and make it work. Or at least understand where the gaps are and what you might do about it to compensate?

And I’ve not talked about data, but it is worth mentioning that with data-rich systems these days – and I heard just the other day, is it two quintillion bytes of data being generated every two days or something ridiculous? That was back in 2017. So, gigantic amounts of data being generated these days and used by computing systems, particularly artificial intelligence systems. So, the rigour associated with that data  – the things that we need to think about on data are potentially just as important as the software. Because if the software is processing rubbish data, you’re probably going to get rubbish results. Or at the very least unreliable results that you can’t trust. So, you need to be thinking about all of those attributes of your data; correct, complete, consistent, etc, etc. I mean, I probably need to do a session on that and maybe I will.

Copyright Statement

That’s the presentation. As you can see, everything in italics and quotes is out of the standard, which is copyright free. But this presentation is copyright of the Safety Artisan.

For More…

And you will find many more presentations and a lot more resources at the website www.safetyartisan.com. Also, you’ll find the paid videos on our Patreon page, which is www.patreon.com/SafetyArtisan or go to Patreon and search for the Safety Artisan.

End

Well, that’s the end of our presentation, and it just remains for me to say thanks very much for listening. Thanks for your time and I look forward to seeing you in the next session, Task 209. Looking forward to it. Goodbye.

End

Categories
Mil-Std-882E Safety Analysis

System Hazard Analysis

In this 45-minute session, The Safety Artisan looks at System Hazard Analysis, or SHA, which is Task 205 in Mil-Std-882E. We explore Task 205’s aim, description, scope, and contracting requirements. We also provide value-adding commentary, which explains SHA – how to use it to complement Sub-System Hazard Analysis (SSHA, Task 204) in order to get the maximum benefits for your System Safety Program.

This is the seven-minute-long demo. The full video is 47 minutes long.

System Hazard Analysis: Topics

  • Task 205 Purpose [differences vs. 204];
    • Verify subsystem compliance;
    • ID hazards (subsystem interfaces and faults);
    • ID hazards (integrated system design); and
    • Recommend necessary actions.
  • Task Description (five slides);
  • Reporting;
  • Contracting; and
  • Commentary.
Transcript: System Hazard Analysis

Introduction

Hello, everyone, and welcome to the Safety Artisan, where you will find professional, pragmatic, and impartial safety training resources and videos. I’m Simon, your host, and I’m recording this on the 13th of April 2020. And given the circumstances when I record this, I hope this finds you all well.

System Hazard Analysis Task 205

Let’s get on to our topic for today, which is System Hazard Analysis. Now, system hazard analysis is, as you may know, is Task 205 in the Mil. Standard 882E system safety standard.

Topics for this Session

What we’re going to cover in this session is purpose, task description, reporting, contracting and some commentary – although I’ll be making commentary all the way through. Going to the back to the top, the yellow highlighting with this and with task 204, I’m using the yellow highlighting to indicate differences between 205 and 204 because they are superficially quite similar. And then I’m using underlining to emphasize those things that I want to really bring to your attention and emphasize. Within task 205, purpose. We’ve got four purposes for this one. Verify subsistent compliance and recommend necessary actions – fourth one there. And then in the middle of the sandwich, we’ve got identification of hazards, both between the subsystem interfaces and faults from the subsystem propagating upwards to the overall system and identifying hazards in the integrated system design. So, quite different emphasis to 204 which was really thinking about subsystems in isolation. We’ve got five slides of task description, a couple on reporting, one on contracting – nothing new there – and several commentaries.

System Requirements Hazard Analysis (T205)

Let’s get straight on with it. The purpose, as we’ve already said, there is a three-fold purpose here; Verify system compliance, hazard identification and recommended actions, and then, as we can see in the yellow, the identifying previously unidentified hazards is split into two. Looking at subsystem interfaces and faults and the integration of the overall system design. And you can see the yellow bit, that’s different from 204 where we are taking this much higher-level view, taking an inter subsystem view and then an integrated view.

Task Description (T205) #1

On to the task description. The contract has got to do it and documented, as usual, looking at hazards and mitigations, or controls, in the integrated system design, including software and human interface. It’s very important that we’ll come onto that later. All the usual stuff about we’ve got to include COTS, GOTS, GFE and NDI. So, even if stuff is not being developed, if we’re putting together a jigsaw system from existing pieces, we’ve still got to look at the overall thing. And as with 204, we go down to the underlined text at the bottom of the slide, areas to consider. Think about performance, and degradation of performance, functional failures, timing and design errors, defects, inadvertent functioning – that classic functional failure analysis that we’ve seen before. And again, while conducting this analysis, we’ve got to include human beings as an integral component of the system, receiving inputs, and initiating outputs.  Human factors were included in this standard from long ago.

Task Description (T205) #2

Slide two. We’ve got to include a review of subsystem interrelationships. The assumption is that we’ve previously done task 204 down at a low level and now we’re building up to task 205. Again, verification of system compliance with requirements (A.), identification of new hazards and emergent hazards, recommendations for actions (B.), but Part C is really the new bit. We are looking at possible independent, dependent, and simultaneous events (C.) including system failures, failures of safety devices, common cause failures, and system interactions that could create a hazard or increase risk. And this is really the new stuff in 205 and we are going to emphasize in the commentary, you’re going to look very carefully at those underlying things because they are key to understanding task 205.

Task Description (T205) #3

Moving on to Slide 3, all new stuff, all in yellow. Degradation of the system or the total system (D.), design changes that affect subsystems (E.). Now, I’ve underlined this because what’s the constant in projects? It’s change. You start off thinking you’re going to do something and maybe the concept changes subtly or not so subtly during the project. Maybe your assumptions change the schedule changes, the resources available change. You thought you were going to get access to something, but it turns out that you’re not. So, all these things can change and cause problems, quite frankly, as I am sure we know. So, we need to deal with not just the program as we started out, but the program as it turns out to be – as it’s actually implemented. And that’s something I’ve seen often go awry because people hold on to what they started out with, partly because they’re frightened of change and also because of the work of really taking note changes. And it takes a really disciplined program or project manager to push back on random change and to control it well, and then think through the implications. So, that’s where strength of leadership comes in, but it is difficult to do.

Moving on now. It says effects of human errors (F.) in the blue, I’ve changed that. Human error implies that the human is at fault, that the human made a mistake. But very often, we design suboptimal systems and we just expect the human operator to cope. Whether it’s fair or unfair or unreasonable, it results in accidents. So, what we need to think about more generally is erroneous human action. So, something has gone wrong but it’s not necessarily the humans’ fault. Maybe the system has induced the human to make an error. We need to think very carefully about.

Moving on, determination (G.), potential contribution of all those components in G. 1. As we said before, all the non-developmental stuff. G.2, have design requirements in the specifications being satisfied? This standard emphasizes specifications and meeting requirements, we’ve discussed that in other lessons. G.3 and whether methods of system implementation have introduced any new hazards. Because of course, in the attempted to control hazards, we may introduce technology or plant or substances that themselves can create problems. So, we need to be wary of that.

Task Description (T205) #4

Moving on to slide four. Now, in 205.2.2, the assumption here is that the PM has specified methods to be used by the contractor. That’s not necessarily true, the PM may not be an expert in this stuff. While they may for contractual or whatever reasons have decided we want the contractor to decide what techniques to use. But the assumption here is that the PM has control and if the contractor decides they want to do something different they’ve got to get the PM’s authority to do that. This is assuming, of course, that the this has been specified in the contract.

And 205.2.3, whichever contractor is performing the system hazard analysis, the SHA, they are expected to have oversight of software development that’s going to be part of their system. And again, that doesn’t happen unless it’s contracted. So, if you don’t ask for it, you’re not going to get it because it costs money. So, if the ultimate client doesn’t insist on this in the contract and police it to be fair because it’s all very well asking for stuff. If you never check what you’re getting or what’s going on, you can’t be sure that it’s really happening. As an American Admiral Rickover once said, “You get the safety you inspect”. So, if you don’t inspect it, don’t expect to get anything in particular, or it’s an unknown. And again, if anything requires mitigation, the expectation in the standard is that it will be reported to the PM, the client PM this is and that they will have authority. This is an assumption in the way that the standard works. If you’re not going to run your project like that, then you need to think through the implications of using this standard and manage accordingly.

Task Description (T205) #5

And the final slide on task description. We’ve got another reminder that the contractor performing the SHA shall evaluate design changes. Again, if the client doesn’t contract for this it won’t necessarily happen. Or indeed, if the client doesn’t communicate that things have changed to the contractor or the subcontractors don’t communicate with the prime contractor then this won’t happen. So, we need to put in place communication channels and insist that these things happen. Configuration control, and so forth, is a good tool for making sure that this happens.

Reporting (T205) #1

So, if we move on to reporting, we’ve got two slides on this. No surprises, the contractor shall prepare a report that contains the results from the analysis as described. First, part A, we’ve got to have a system description. Including the physical and functional characteristics and subsystem interfaces. Again, always important, if we don’t have that system description, we don’t have the context to understand the hazard analysis that had been done or not being done for whatever reason. And the expectation is that there will be reference to more detailed information as and when it becomes available. So maybe detailed design stuff isn’t going to emerge until later, but it has to be included. Again, this has got to be required.

Reporting (T205) #2

Moving onto parts B and C. Part B as before we need to provide a description of each analysis method used, the assumptions made, and the data used in that analysis. Again, if you don’t do this, if you don’t include this description, it’s very hard for anybody to independently verify that what has been done is correct, complete, and consistent. And without that assurance, then that’s going to undermine the whole purpose of doing the analysis in the first place.

And then part C, we’ve got to provide the analysis results and at the bottom of this subparagraph is the assumption. The analysis results could be captured in the hazard tracking system, say the hazard log, but I would only expect the sort of leading to be captured in that hazard log. And the detail is going to be in the task 205 hazard analysis report, or whatever you’re calling it. We’ve talked about that before, so I’m not going to get into that here.

Contracting

And then the final bit of quotation from the standard is the contracting. And again, all the same things that you’ve seen before. We need to require the task to be completed. It’s no good just saying apply Mil. Standard 882E because the contractor, if they understand 882E, they will tailor it to suit selves, not the client. Or if they don’t understand 882E they may not do it at all, or just do it badly. Or indeed they may just produce a bunch of reports that have got all the right headings in as the data item description, which is usually supplied in the contract, but there may be no useful data under those headings. So, if you haven’t made it clear to the contractor, they need to conduct this analysis and then report on the results – I know it sounds obvious. I know this sounds silly having to say this, but I’ve seen it happen. You’ve got a contractor that does not understand what system safety is.

(Mind you, why have you contracted them in the first place to do this? You should know that you should have done your research, found out.)

But if it’s new to them, you’re going to have to explain it to them in words of one syllable or get somebody else to do it for them. And in my day job, this is very often what consultancies get called in to do. You’ve got a contractor who maybe is expert building tanks, or planes, or ships, or chemical plants, or whatever it might be, but they’re not expert in doing this kind of stuff. So, you bring in a specialist. And that’s part of my day job.

So, getting back to the subject. Yes, we’ve got to specify this stuff. We’ve got to specify it early, which implies that the client has done quite a lot of work to work this all out. And again, the client may above the line, as we say, say engage a consultant or whoever to help them with this, a specialist. We’ve got to include all of the details that are necessary. And of course, how do you know what’s necessary, unless you’ve worked it out. And you’ve got to supply the contractor, it says concept of operations, but really supplying the contractor with as much relevant data and information as you can, without bogging them down. But that context is important to getting good results and getting a successful program.

Illustration

I’ve got a little illustration here. The supposition in the standard in Task 205 is we’ve got a number of subsystems and there may be some other building blocks in there as well. And some infrastructure we’ve going to have probably some users, we’re going to have an operating environment, and maybe some external systems that our system, or the system of interest, interfaces with or interacts with in some way. And that interaction might be deliberate, or it might be just in the same operating environment at night. And they will interact intentionally or otherwise.

Commentary – Go Early

With that picture in mind, let’s think about some important points. And the first one is to get 205, get some 205-work done early. Now, the implication in the standard by the numbering and when you read the text is that subsystem hazard analysis comes first. You do those hexagonal building blocks first and then you build it up and task 205 comes after the subsystem hazard analysis. You thought, “Well, you’ve already got the SHHAs for each subsystem and then you build the SHA on top”. However, if you don’t do 205 early, you’re going to lose an opportunity to influence the design and to improve your system requirements. So, it’s worth doing an initial pass of 205 first, top-down, before you do the 204 hexagons and then come back up and redo 205. So, the first pass is done early to gain insight, to influence the design, and to improve your requirements, and to improve, let’s say, the prime contractor’s appreciation and reporting of what they are doing. And that’s really, dare I say, a quick and dirty stab at 205 could be quite cheap and will probably the payback/the return on investment should be large if you do it early enough. And of course, act on the results.

And then the second part is more about verifying compliance, verifying those as required interfaces, and looking at emergent stuff, stuff that’s emerged – the devil’s in the detail as the saying goes. We can look at the emerging stuff that’s coming out of that detail and then pull all that together and tidy up it up and look for emergent behaviour.

Commentary – Tools & Techniques

Looking at tools and techniques, most safety analysis techniques that we use look at single events or single failures only in isolation. And usually, we expect those events and failures to be independent. So, there’re lots of analyses out there. Basic fault tree analysis, event tree analysis. Well, event tree is slightly different in that we can think about subsequent failures, but there’re lots of basic techniques out there that will really only deal with a single failure at a time. However, 205.2.1C requires us to go further. We’ve got to think about dependent simultaneous events and common cause failures. And for a large and complex system, each of those can be a significant undertaking. So, if we’re doing task 205 well, we are going to push into these areas and not simply do a copy of task 204, but at a higher level. We’re now really talking about the second pass of 205. The previous, quick and dirty, 205 is done. The task 204 on the subsystems is done. Now we’re pulling it all together.

Dependent & Simultaneous Events

Let’s think about independent simultaneous events. First, dependent failures. Can an initial failure propagate? For example, a fire could lead to an explosion or an explosion could lead to a fire. That’s a classic combination. If something breaks or wears could be as simple as components wearing and then we get debris in the lubrication system. Could that – could the debris from component wear clog up the lubrication system and cause it to fail and then cause a more serious seizure of the overall system? Stuff like that. Or there may be more subtle functional effects. For example, electric effects, if we get a failure in an electrical system or even non-failure events that happen together. Could we get what’s called a sneak circuit? Could we get a reverse flow of current that we’re not expecting? And could that cause unexpected effects? There’s a special technique we’re looking at called sneak circuits analysis. That’s sneak, SNEAK, go look it up if you’re interested. Or could there be multiple effects from one failure? Now, I’ve already mentioned fire. It’s worth repeating again. Fire is the absolute classic. First, the effects of fire. You’ve got the fire triangle. So, to get fire, we need an inflammable substance, we need an ignition source, and we need heat. And without all three, we don’t get a fire. But once we do get a fire, all bets are off, and we can get multiple effects. So, we recall, you might remember from being tortured doing thermodynamics in class, you might remember the old equation that P1V1T1 equals P2V2T2. (And I’ve put R2 that for some reason, so sorry about that.)

What that’s saying is, your initial pressure, volume and temperature multiplied together, P1V1T1, is going to be the same as your subsequent pressure, volume and temperature multiply together, P2V2T2. So, what that means is if you dramatically increase the temperature say, because that’s what a fire does, then your volume and your pressure are going to change. So, in an enclosed space we get a great big increase in pressure, or if we’re in an unenclosed space, we’re going to get an increase in volume in a [gas or] fluid. So, if we start to heat the [gas or] fluid, it’s probably going to expand. And then that could cause a spill and further knock-on effects. And fire, as well as effect making pressure and volume changes to the fluids, it can weaken structures, it makes smoke, and produces toxic gases. So, it can produce all kinds of secondary hazardous effects that are dangerous in themselves and can mess up your carefully orchestrated engineering and procedural controls. So, for example, if you’ve got a fire that causes a pressure burst, you can destroy structures and your fire containment can fail. You can’t send necessarily people in to fix the problem because the area is now full of smoke and toxic gas. So, fire is a great example of this kind of thing where you think, “Well, if this happens, then this really messes up a lot of controls and causes a lot of secondary effects”. So, there’s a good example, but not the only one.

And then simultaneous events, a hugely different issue. What we’re talking about here is we have got undetected, or latent, failures. Something has failed, but it’s not apparent that it’s failed, we’re not aware, and that could be for all sorts of reasons. It could be a fatigue failure. We’ve got something that’s cracked, or it could be thermal fatigue. So, lots of things that can degrade physical systems, make them brittle. For example, an odd one, radiation causes most metals to expand and neutron bombardment makes them brittle. So, it can weaken things, structure and so forth. Or we might have a safety system that has failed, but because we’ve not called upon it in anger, we don’t notice. And then we have a failure, maybe the primary system fails. We expect the secondary system to kick in, but it doesn’t because there’s been some problem, or some knock-on effect has prevented the secondary system from kicking in. And I suspect we’ve all seen that happen.

My own experience of that was on a site I was working on. We had a big electricity failure, a contractor had sawed through the mains electricity cable or dug through it. And then, for some unknown reason, the emergency generators failed to kick in. So, that meant that a major site where thousands of people worked had to be evacuated because there was no electricity to run the computers. Even the old analogue phones failed after a while. Today, those phones would be digital, probably voice over IP, and without electricity, they’d fail instantly. And eventually, without power for the plumbing, the toilets back up. So, you’re going to end up having to evacuate the entire site because it’s unhygienic. So, some effects can be very widespread. Just because you had a late failure, and your backup system didn’t kick in when you expected it to.

So how can we look at that? Well, this is classic reliability modelling territory. We can look at meantime between failures, MTBF, and meantime to repair (MTTR) and therefore we could work out what the exposure time might be. We can work out, “What’s the likelihood of a latent failure occurring?” If we’ve got an interval, presumably we’ve going to test the system periodically. We’ve got to do a proof test. How often do we have to do the proof test to get a certain level of reliability or availability when we need the system to work? And we can look at synchronous and asynchronous events. And to do that, we can use several techniques. The classic ones, reliability, lock diagrams and fault tree analysis. Or if we’ve got repairable systems, we can use Markov chain modelling, which is very powerful. So, we can bring in time-dependent effects of systems failing at certain times and then being required, or systems failing and being repaired, and look at overall availability so that we can get an estimate of how often the overall system will be available. If we look at potential failures in all the redundant constituent parts. Lots of techniques there for doing that, some of them quite advanced. And again, very often this is what safety consultants, this is what we find ourselves doing so.

Common Cause Failures

Common cause failure, this is another classic. We might think about something very obvious and physical, maybe we get debris, maybe we’ve got three sets of input channels guarded by filters to stop debris getting into the system, but what if debris blocks all the filters so we get no flow? So, obvious – I say obvious – often missed sources of sometimes quite major accidents. Or let’s say something more subtle, we’ve got three redundant channels, or a number of redundant channels, in an electronic system and we need two out of three to work, or whatever it might be. But we’ve got the same software working each channel. So, if the software fails systematically, as it does, then potentially all three channels will just fail at the same time.

So, there’s a good example of non-independent failures taking down a system that on paper has a very high reliability but actually doesn’t. Once you start considering common cause failure or common mode analysis. So, really what we would like is we would like all redundancy to be diverse if possible. So, for example, if we wanted to know how much fuel we had left in the aeroplane, which is quite important if you want the engines to keep working, then we can employ diverse methods. We can use sensors to measure how much fuel is in the tanks directly and then we can cross-check that against a calculated figure where we’ve entered, let’s say, how much fuel was in the tanks to start with. And then we’ve been measuring the flow of fuel throughout the flight. So, we can calculate or estimate the amount of fuel and then cross-check that against the actual measurements in the tanks. So, there’s a good diverse method. Now, it’s not always possible to engineer a diverse method, particularly in complex systems. Sometimes there’s only really one way of doing something. So, diversity kind of goes out of the window in such an engineered system.

But maybe we can bring a human in.

So, another classic in the air world, we give pilots instruments in order to tell them what’s going on with the aeroplane, but we also suggest that they look out the window to look at reality and cross-check. Which is great if you’re not flying a cloud or in darkness and there are maybe visual references so you can’t necessarily cross-check. But even things like system failures, can the pilot look out the window and see which propeller has stopped turning? Or which engine the smoke and flames coming out of? And that might sound basic and silly, but there have been lots of very major accidents where that hasn’t been done and the pilots have shut down the wrong engine or they’ve managed the wrong emergency. And not just pilots, but operators of nuclear power plants and all kinds of things. So, visual inspection, going and looking at stuff if you have time, or take some diverse way of checking what’s going on, can be very helpful if you’re getting confusing results from instrument readings or sensor readings.

And those are examples of the terrific power of human diversity. Humans are good at taking different sensory inputs and fusing them together and forming a picture. Now, most of the time they fuse the data well and they get the correct picture, but sometimes they get confused by a system or they get contradictory inputs and they get the wrong mental model of what’s going on and then you can have a really bad accident. So, thinking about how we alert humans, how we use alarms to get humans attention, and how we employ human factors to make sure that we give the humans the right input, the right mental picture, mental model, is very important. So, back to human factors again, especially important, at this level for task 205.

And of course, there are many specialist common cause failure analysis techniques so we can use fault trees. Normally in a fault tree when you’ve got an and gate, we assume that those two sub-events are independent, but we can use ‘beta factors’ (they’re called) to say, “Let’s say event a and event b are not independent, but we think that 50 percent or 10 percent of the time they will happen at the same time”. So, you can put that beta factor in to change the calculation. So, fault trees can cope with non-independent fate is providing you program the logic correctly. You understand what’s going on. And maybe if there’s uncertainty on the beta factors, you must do some sensitivity modelling on the tree with different beta factors. Or you run multiple models of the tree, but again, we’re now talking quantitative techniques with the fault tree, maybe, or semi-quantitative. We’re talking quite advanced techniques, where you would need a specialist who knows what they do in this area to come up with realistic results, that sensitivity analysis. The other thing you need to do is if the sensitivity analysis gives you an answer that you don’t want, you need to do something about that and not just file away the analysis report in a cupboard and pretend it never happened. (Not that that’s ever happened in real life, boys and girls, never, ever, ever. You see my nose getting longer? Sorry, let’s move on before I get sued.)

So other classic techniques. Zonal hazard analysis, it looks at lots of different components in a compartment. If component A blows up, does it take out everything else in that compartment? Or if the compartment floods, what functionality do we lose in there? And particularly good for things like ships and planes, but also buildings with complex machinery. Big plant where you’ve got different stuff in different locations. There’re also things called particular risk analysis where you think of, and these tend to be very unusual things where you think about what a fan blade breaks in a jet engine. Can the jet engine contain the fan blade failure? And if not, where you’ve got very high energy piece of metal flying off somewhere – where does that go? Does that embed itself in the fuselage of the aeroplane? Does it puncture the pressure hull of the aeroplane? Or, as has sadly happened occasionally, does it penetrate and injure passengers? So, things like that, usually quite unusual things that are all very domain or industry specific. And then there are common mode analysis techniques and a good example of a standard that incorporates those things is ARP 4761. This is a civil aircraft standard which looks at those things quite well, for example, there are many others.

Summary

In summary, I’ve emphasized the differences between Task 205 and 204. So, we might do a first pass 205 and 204 where we’re essentially doing the same thing just at different levels of granularity. So, we might do the whole system initially 205, one big hexagon, and then we might break down the jigsaw and do some 204 at a more detailed level. But where 205 is really going to score is in the differences between 204. So instead of just repeating, it’s valuable to repeat that analysis at a higher-level, but really if we go to diversify if we want success. So, we need to think about the different purpose and timing of these analyses. We need to think about what we’re going to get out of going top-down versus bottom-up, different sides of the ‘V’ model let’s say.

We need to think about the differences of looking at internals versus external interfaces and interactions, and we need to think of appropriate techniques and tools for all those things – and, of course, whether we need to do that at all! We will have an idea about whether we need to do that from all the previous analysis. So, if we’ve done our PHI or PHA, we’ve looked at the history and some simple functional techniques, and we’ve involved end-users and we’ve learnt from experience. If we’ve done our early tasks, we’re going to get lots of clues about how much risk is present, both in terms of the magnitude of the risk and the complexity of the things that we’re dealing with. So, clearly, we’ve got a very complex thing with lots of risks where we could kill lots of people, we’re going to do a whole lot more analysis than for a simple low-risk system. And we’re going to be guided by the complexity and risks and the hot spots where they are and go “Clearly, I’ve got a particular interface or particular subsystem, which is a hotspot for risk. We’re going to concentrate our effort there”. If you haven’t done the early analysis, you don’t get those clues. So, you do the homework early, which is quite cheap and that helps you. Direct effort, the best return on investment.

The Second major bullet point, which I talk about this again and again. That the client and end-user and/or the prime contractor need to do analysis early in order to get the benefits and to help them set requirements for lower down the hierarchy and pass relevant information to the sub-contractors. Because the sub-contractors, if you leave them in isolation, they’ll do a hazard analysis in isolation, which is usually not as helpful as it could be. You get more out of it if you give them more context. So really, the ultimate client, end-user, and probably the prime as well, both need to do this task, even if they’re subcontracting it to somebody else. Whereas, maybe the sub-system hazard analysis 204 could be delegated just down to the sub-system contractors and suppliers. If they know what they’re doing and they’ve got the data to do it, of course. And if they haven’t, there’s somebody further up the food chain on the supply chain may have to do that.

And lastly, 204 and 205 are complimentary, but not the same. If you understand that and exploit those similarities and differences, you will get a much more powerful overall result. You’ll get synergy. You’ll get a win-win situation where the two different analyses complement, reinforce each other. And you’re going to get a lot more success probably for not much more money and effort time. If you’ve done that thinking exercise and really sought to exploit the two together, then you’re going to get a greater holistic result.

Copyright

So, that’s the end of our session for today. Just a reminder that I’ve quoted from the Mil. Standard 882, which is copyright free, but the contents of this presentation are copyright Safety Artisan, 2020.

For More …

And for more lessons and more resources, please do visit www.safetyartisan.com and you can see the videos at www.patreon.com/safetyartisan.

End

That’s the end of the lesson on system hazard analysis task 205. And it just reminds me to say thanks very much for watching and look out for the next in the series of Mil. Standard 882 tasks. We will be moving on to Task 206, which is Operating and Support Hazard Analysis (OSHA), a quite different analysis to what we’ve just been talking. Well, thanks very much for watching and it’s goodbye from me.

The End

You can find a free pdf of the System Safety Engineering Standard, Mil-Std-882E, here.

Categories
Mil-Std-882E Safety Analysis

Sub-System Hazard Analysis

In this video lesson, The Safety Artisan looks at Sub-System Hazard Analysis, or SSHA, which is Task 204 in Mil-Std-882E. We explore Task 204’s aim, description, scope, and contracting requirements. We also provide value-adding commentary and explain the issues with SSHA – how to do it well and avoid the pitfalls.

This is the seven-minute demo, the full video is 40-minutes’ long.

Topics: Sub-System Hazard Analysis

  • Preamble: Sub-system & System HA.
  • Task 204 Purpose:
    • Verify subsystem compliance;
    • Identify (new) hazards; and
    • Recommend necessary actions.
  • Task Description (six slides);
  • Reporting;
  • Contracting; and
  • Commentary.
Transcript: Sub-System Hazard Analysis

Introduction

Hello, everyone, and welcome to the Safety Artisan, where you will find professional, pragmatic, and impartial instruction on all things system safety. I’m Simon – I’m your host for today, as always and it’s the fourth of April 22. With everything that’s going on in the world, I hope that this video finds you safe and well.

Sub-System Hazard Analysis

Let’s move straight on to what we’re going to be doing. We’re going to be talking today about subsystem hazard analysis and this is task 204 under the military standard 882E. Previously we’ve done 201, which was preliminary hazard identification, 202, which is preliminary hazard analysis, and 203, which is safety requirements hazard analysis. And with task 204 and task 205, which is system has analysis, we’re now moving into getting stuck into particular systems that we’re thinking about, whether they be physical systems or intangible. We’re thinking about the system under consideration and I’m really getting into that analysis.

Topics for this Session

So, the topics that we’re going to cover today, I’ve got a little preamble to set things in perspective. We then get into the three purposes of task 204. First, to verify compliance. Secondly, to identify new hazards. And thirdly, to recommend necessary actions. Or in fact, that would be recommend control measures for hazards and risks. We’ve got six slides of task description, a couple of slides on reporting, one on contracting, and then a few slides on some commentary where I put in my tuppence worth and I’ll hopefully add some value to the basic bones of the standard. It’s worth saying that you’ll notice that subsystem is highlighted in yellow and the reason for that is that the subsystem and system hazard analysis tasks are very, very similar. They’re identical except for certain passages and I’ve highlighted those in yellow. Normally I use a yellow highlighter to emphasize something I want to talk about. This time around, I’m using underlining for that and the yellow is showing you what these different for subsystem analysis as opposed to system. And when you’ve watched both sessions on 204 and 205, I think you’ll see the significance of why I’ve done.

Preamble – Sub-system & System HA

Before we get started, we need to explain the system model that the 882 is assuming. If we look on the left-hand side of the hexagons, we’ve got our system in the centre, which we’re considering. Maybe that interfaces with other systems. They work within operating environment; hence we have the icon of the world, and the system and maybe other systems are there for a purpose. They’re performing some task; they’re doing some function and that’s indicated by the tools. We’re using the system to do something, whatever it might be.

Then as we move to the right-hand side, the system is itself broken down into subsystems. We’ve got a couple here. We’ve got sub-system A and B and then A further broken down into A1 and A2, for example. There’s some sort of hierarchy of subsystems that are coming together and being integrated to form the overall system. That is the overall picture that I’d like to bear in mind while we’re talking about this. The assumption in the 882, is we’re going to be looking at this subsystem hierarchy bottom upwards, largely. We’ll come on to that.

System Requirements Hazard Analysis (T204)

Purpose of the task, as I’ve said before, it’s threefold. We must verify subsystem compliance with requirements. Requirements to deal with risk and hazards. We must identify previously unidentified hazards which may emerge as we’re working at a lower level now. And we must recommend actions necessary. That’s further requirements to eliminate all hazards or mitigate associated risks. We’ll keep those three things in mind and that will keep coming up.

Task Description (T204) #1

The first of six slides on the task description. Basically, we are being told to perform and document the SSHA, sub-system hazard analysis. And it’s got to include everything, whether it be new developments, COTS, GOTS, GFE, NDI, software and humans, as we’ll see later. Everything must be included. And we’re being guided to consider the performance of the subsystem: ‘What it is doing when it is doing it properly’. We’ve got to consider performance degradation, functional failures, timing errors, design errors or defects, and inadvertent functioning – we’ll come back to that later. And while we’re doing analysis, we must consider the human as a component within the subsystem dealing with inputs and making outputs. If, of course, there is an associated human. We’ve got to include everything, and we’ve got to think about what could go wrong with the system.

Task Description (T204) #2

The minimum that the analysis has got to cover is as follows. We’ve got to verify subsystem compliance with requirements and that is to say, requirements to eliminate hazards or reduce risks. The first thing to note about that is you can’t verify compliance with requirements if there are no requirements. if you haven’t set any requirements on the subsystem provider or whoever is doing the analysis, then there’s nothing to comply with and you’ve got no leverage if the subsystem turns out to be dangerous. I often see it as it gets missed. People don’t do their top-down systems engineering properly; They don’t think through the requirements that they need; and, especially, they don’t do the preliminary hazard identification and analysis that they need to do. They don’t do Task 203, the SRHA, to think about what requirements they need to place further down the food chain, down the supply chain. And if you haven’t done that work, then you can’t be surprised if you get something back that’s not very good, or you can’t verify that it’s safe. Unfortunately, I see that happen often, even on exceptionally large projects. If you don’t ask, you don’t get, basically.

We’ve got two sub-paragraphs here that are unique to this task. First, we’ve got to validate flow down of design requirements. “Are these design requirements valid?”, “Are they the right requirements?” From the top-level spec down to more detailed design specifications for the subsystem. Again, if you haven’t specified anything, then you’ve got no leverage. Which is not to say that you have to dive into massive detail and tell the designer how to do their job, but you’ve got to set out what you want from them in terms of the product and what kind of process evidence you want associated with that product.

And then the second sub-paragraph, you’ve got to ensure design criteria in the subsystem specs have been satisfied. We need to verify that they’re satisfied, and that V and V of subsystem mitigation measures or risk controls have been included in test plans and procedures. As always, the Mil. standard 882 is the American standard, and they tend to go big on testing. Where it says test plans and procedures that might be anything – you might have been doing V and V by analysis, by demonstration, by testing, by other means. It’s not necessarily just testing, but that’s often the assumption.

Task Description (T204) #3

We must also identify previously unidentified hazards because we are now down at a low level of detail in a subsystem and stuff probably will emerge at that level that wasn’t available before. First, number one, we’ve got to ensure the implementation of subsystem design requirements and controls. And ensure that those requirements and controls have not introduced any new hazards, because very often accidents occur. Not because the system has gone wrong – the system is working as advertised – but the hazards with normal operation maybe just weren’t appreciated and guarded against or we just didn’t warn the operators that something might happen that they needed to look out for. A common shortfall, I’m afraid.

And number two, we’ve got to determine modes of failure down to component failure and human errors, single points of failure, common-mode failures, effects when failures occur in components, and from functional relationships. “What happens if something goes wrong over on this side of the system or subsystem and something else is happening over here?” What are those combinations? What could result? And again, we’ve got to consider hardware and software, including all non-developmental type stuff, and faults, and occurrences. Again, I see very often, buyers/purchases don’t think about the off the shelf stuff in advance or don’t include it. And then sometimes also you see contractors going “This is off the shelf, so we’re not analysing it.” Well, the standard requires that they do analyse it to the extent practicable. And they’ve got to look at what might go wrong with all of this non-development to stuff and integrate the possible effects and consider. That’s another common gotcha, I’m afraid. we do need to think about everything, whether it’s developmental or not.

Task Description (T204) #4

And then part C, recommending actions necessary to eliminate hazards if we can. Very often we can’t, of course, and we have to mitigate. We must reduce or minimize the associated risk of those hazards. In terms of the harm that might come to people. We’ve got to ensure that system-level hazards, it says attributed. Maybe we believe when we did the earlier analysis that the subsystem could contribute to a higher-level hazard, or maybe we’ve allocated some failure budget to this particular subsystem, which it has got to keep to if we’re going to meet the higher-level targets. You can imagine lots of these subsystems all feeding up a certain failure rate and different failure modes. And overall, when you pull it all together, we may have to meet some target or reduce the number of failures in their propagation upwards in order to manage hazards and risks. We’ve got to make sure that we’ve got adequate mitigation controls of these potential hazards are implemented in the design.

If we think back to the hierarchy, we prefer to fix things in the design, eliminate the hazard if possible, or make changes to the design to eliminate or reduce the hazard, rather than just rely on human beings to catch the problem and deal with it further downstream. It’s far more effective and cheaper, in the long run, to fix things in design they are more effective controls. Certainly, in this standard in Australian law, and in the UK and elsewhere, you will find either regulations or law or codes of practice or recognized and accepted good practice that says, “You should do this”. It’s a very, very common requirement and we should pretty much assume that we have to do this.

Task Description (T204) #5

Interesting clause here in 2.2, it says if no specific hazard analysis techniques are directed or the contractor wants to take a different route to what is directed, then they’ve got to obtain approval from the program manager. If the PM (Project Manager) hasn’t specified analysis techniques, and they may not wish to, they may just wish to say you’ll do whatever analysis is required in order to identify hazards and mitigate them. But in many industries, there are certain ways of doing things and I’ve said before in previous lessons, if you don’t specify that you want something, then contractors will very often cut the safety program to the bone in order to be the cheapest bid. the customer will get what they prioritize. If the customer prioritizes a cheap bid and doesn’t specify what they want, then they will get the bare minimum that the contractor thinks they can get away with. If you don’t ask, you don’t get – Becoming a theme that isn’t it?

Task Description (T204) #6

Let’s move on to 2.3. Returning to software, we’ve got to include that. The software might be developed separately, but nevertheless, the contractor performing the SSHA shall monitor the software development, shall obtain data from each phase of the software development process in order to evaluate the contribution of the software to the subsystem hazard analysis. There’s no excuse for just ignoring the software and treating it as a black box. Of course, very often these days the software is already developed. It’s a GFE or NDI item, but there still should be evidence available or you do a black-box analysis of the subsystem that the software is sitting in. Again, if the software developer reports any identified hazards, they’ve got to be reported to the program manager in order to request appropriate direction.

This assumes a level of interaction between the software developers right up the chain to the program manager. Again, this won’t happen unless the program manager directs it and pays for it. If the PM doesn’t want to pay for it, then they are either going to have to take a risk on not knowing about the functionality of the software that’s hidden within the subsystem. Or they’re going to deal with it some other way, which is often not effective. The PM needs to do a lot of work upfront in order to think what kind of problems there might be associated with a typical subsystem of whatever kind it is we’re dealing with. And think about “How would I deal with the associated risks?” “What’s the best way to deal with them in the circumstances?” If I’m buying stuff off the shelf and I’m not going to get access to hazard analysis or other kinds of evidence, how am I going to deal with them? Big questions.

And then 2.4, the contractor shall update the SSHA following changes, including software design changes. Again, we can’t just ignore those things.  That’s slide six out of six. Let’s move on to reporting.

Reporting (T204) #1

The first slide, contractor’s got to prepare a report that contains results from the task, including within the system description, physical and functional characteristics of the system, a list of the subsystems, and a detailed description of the subsystem being analysed, including its boundaries. And from other videos, you’ll know how much and how often I emphasize knowing where the boundaries are because you can’t really do effective safety analysis and safety management on an unbounded system. It just doesn’t work. There’s a requirement here for quite a lot of information reference to more detailed descriptions as they become available. The standard says they shall be supplied. That’s a lot of information that probably texts and pictures of all sorts of stuff and that’s going to need to go into a report. And typically, we would expect to see a hazard analysis report or a HAR with this kind of information in it. Again, if the PM/customer doesn’t specify that HAR, then they’re not going to get it and they’re not going to get textual information that they need to manage the overall system.

Reporting (T204) #2

So, if we move on to parts B and C of the reporting requirement. We’ve got to describe hazard analysis methods and techniques, provide a description of each method and the technique used, and a description of the assumptions made. And it says for each qualitative or quantitative data. This is another area that often gets missed. If you don’t know what techniques have been used and you don’t know the assumptions that almost certainly that subsystem analyser will have to make because they probably don’t have visibility in the rest of the system. If you don’t have that information, it becomes very difficult to verify the hazard analysis work and to have confidence in it.

And the hazard analysis results. Content and format vary. Something else the PM is going to think about and specify upfront. Then results should be captured the hazard tracking system. Now, usually, this hazard tracking system is hazard log. It might be a database, a spreadsheet or even a word document, or something like that. And usually, in the hazard tracking system, we have the leading particulars. We don’t always have, in fact, we shouldn’t have, every little piece of information in the hazard tracking system because it will quickly become unwieldy. Really, we want the hazard log to have the leading particulars of all the hazards, causes, consequences and controls. And then the hazard log should refer out to that hazard analysis report or other reports and data, whatever they’re called, other records.

If we go back up, this reemphasizes the kind of detail that’s here in 2.5 A. That really shouldn’t be going in the hazard log. That should be going in a separate report which the hazard log/the hazard tracking system refers to. Otherwise, it all gets that unwieldy.

Contracting

I’ve said repeatedly the PM needs to think about this and ask for that.

Contracting; The standard assumes that the information in A to H below is specified way up front in the request for proposal. That’s not always possible to do in full detail, but nevertheless, you’ve got to think about these things really early and include them in the contractual documentation. And again, if your if you’re running a competition, by the time you get to the final RFP, you need to make sure that you’re asking for what you really need. maybe run a preliminary expression of interest or pre-competition exercise in order to tease out, detect. We’ve got to impose task 204 (A.) as a requirement. We may have to specify which people we want to involve, which functional specialists, which discipline specialists (B.). We want to get involved to address this work. Identification of subsystems to be analysed (C.). Well, if you don’t know what the design is upfront, we can’t always do that, but you could say all.

You may specify desired analysis methodologies and techniques (D.). And again, that’s largely domain dependent. We tend to do safety in certain ways in different worlds, in the air world is done in a particular way. in the maritime world, it’s a different way. With Road or Off-Road Vehicle, it’s done in a particular way, etc, etc., whatever it might be. Chemical plant, whatever. If they’re known hazards, hazardous areas or other specific items be examined or excluded (E.) because they’re covered adequately elsewhere. The PM or the client has got to provide technical data on all those non-development developmental items (F.), particularly if they’re specifying that the contractor will use them. If the client says “You will use this. You will use these tires, therefore, this data with these tires” or whatever it might be, you’re going to – we want a system that’s going to use to standardized spares of standardized fuel or whatever it might be or is maintainable by technicians and mechanics with these standard skill sets. There may be all sorts of reasons for asking or forcing contracts to do certain things, in which case the purchaser is responsible for providing that data.

And again, many purchases forget to do that entirely or do it very badly, and then that can cripple a safety program. What’s the concept of operations (G.). What are we going to do with this stuff? What’s the context? What’s the big picture? That’s important. And any other specific requirements (H.). What risk matrix? What risk definitions are we using on this program? Again, important otherwise, different contractors do their own thing, or they do nothing at all. And then the client must pick up pieces afterwards, which is always time-consuming and expensive and painful. And it tends to happen at the back of a program when you’re under time pressure anyway. It’s never a happy place to be. do make sure that clients and purchases that you’ve done your homework and specified this stuff upfront, even if it turns out to be not the best thing you could have specified, it’s better to have an 80 percent solution that’s pretty standard and locked down.

Commentary #1

That’s the wording that’s in the task with some commentary by myself. Now some additional commentary. It says right up front, areas to consider include performance, performance degradation, functional failures, timing errors, design errors or defects and inadvertent function. What we have here basically is a causal analysis, there will be some simple techniques that you can use to identify this kind of stuff. Something like a functional failure analysis or a failure modes effects analysis, which is like an FFA, but an FMEA requires design to work on. And, FMEA, a variant of FME is FMECA, where we include the criticality of the failure as it possibly propagates out the hierarchy of the system.

These sorts of techniques will think about what could go wrong, no function when required, inadvertent function – the subsystem functions when it’s not supposed to – and incorrect function, and there’s often multiple versions of incorrect function. considering all of those causes, all of those failure modes and if we’re doing a big safety program on something quite critical, very often the those identified faults and failures and failure modes will feed into the bottom of a fault tree where we have a hierarchical build-up of causation and we look at how redundancy and mitigation and control measures mitigate those low-level failures and hopefully prevent them from becoming full-blown incidents and accidents.

And these techniques, particularly the FFA in the FMEA, are also good for hazard identification and for investigating performance and non-compliance issues. you can apply an FFA and FMEA those type of techniques to a specification and say “We’ve asked for this. What could happen if we get what we ask for?” What could go wrong? And, what could go wrong with these requirements?

Commentary #2

Now, the second part that I’ve chosen to highlight a consideration of the human within a subsystem and this is important. Traditionally, it’s not always been done that well. Human factors, I’m glad to say is becoming more prominent and more used both because in many, many systems, human is a key component, is a key player in the overall system. And in the past, we have tended to build systems and then just expect the human operator and maintainer to cope with the vicissitudes of that system. maybe the system isn’t that well designed in terms of it is not very usable, its performance depends on being lovingly looked after and tweaked and maybe systems are vulnerable to human error, and even induce human error. We need to get a lot better at designing systems for human use.

So, we could use several techniques. We could use a HAZOP, a hazard analysis operability study to consider information flows to and from the human. There are lots of specialist human factors analyses out there. And I’m hoping to run a series of human factors sessions, interviewing a very knowledgeable colleague of mine but more on that later. that will come in due course. We’ll look at those specialist human analysis techniques. But there’s been a couple of conceptual models around for quite a long time, about 20 years now at least, for how to think about humans in the system.

Human-System Models

So, we’ve got a 5M model and the SHELL model. I’m just going to briefly illustrate those. Now, both models are taken from the US Federal Aviation Authority System Safety Handbook, which dates to the end of 2000. These have been around a long time and they were around before the year 2000, and they’re quite long in the tooth.

We’ve got the SHELL model, which considers our software, hardware, environments and live-ware – the human. And there’s quite a nice checklist on Wikipedia for things to consider. We’re considering all the different interfaces between those different elements. That’s at the hyperlink you can see at the bottom of the slide.

Then on the right-hand side, we’ve got the 5M model and apologies for the gendered language. Where the five Ms are the man/the human, the machine, management, the media – and the media is the environment for operating and maintenance environment – and then in the middle is the mission. the humans, the machines, the systems, and the management come together in order to perform a mission within a certain environment. that’s another very useful way of conceptualizing our contribution of humans and interaction between human and system. Human operators usually are maintainers, frontline staff, and management, all in a particular operating environment and environmental context and how they come together to accomplish the mission or the function of the system, whatever it might be.

Now a word of caution, on this. It’s very possible to spend gigantic sums of money on human analysis. very often we tend to target it at the most critical points and we very often target it at the operator, particularly for those phases of operation where the operator must do things in a limited amount time. the operator will be under pressure and if they don’t take the right action within a certain time, something could go wrong. we do tend to target this analysis in those areas and tend to spend money hopefully in a sensible and targeted way.

Commentary #3

My final slide on the additional commentary. The other things we’ve talked about for this task, compliance checking. We should get a subsystem specification. If we don’t get a subsystem specification, well, what are the expectations on the subsystem? Are they documented anywhere? Is it in the consent to box? Is there an interface requirement document or are there interface control documents for other systems that or subsystems that interface with our subsystem – anywhere where we can get information. if we have a subsystem spec, a bunch of functional requirements say, early on we could do a functional failure analysis of those functional requirements. we can do this work really quite early if we need to and think about, “Well, what interfaces are expected or required from our subsystem?” versus “What is our subsystem actually do?” any mismatches that could give rise to problems.

So, this is a type of activity where we’re looking for continuity and we’re looking for coherence across the interface. And we’re looking for things to join up. And if they don’t join up or they’re mismatched, then there’s a potential problem. And, as we look down into the subsystem, are there any derived safety requirements from above that says this subsystem needs to do this or not do that in order to manage a hazard? Those are important to identify.

Again, if it’s not been done probably the subsystem contractor won’t do it because it’s extra expense. And they may well truly believe that they don’t need to. We’re all proud of the things that we do, and we feel sometimes emotionally threatened if somebody suggests a piece of kit might go wrong and it does blind people to potential problems.

If going the other way, we are a higher-level authority where a system prime contractor or something and we’ve got to look at the documentation from a subsystem supplier. Well, we might find out some information from sales brochures or feature lists, or there might be a description of the benefits or the functions of the system with its outputs. We hopefully should be able to get hold of some operating and maintenance manuals. And very often those manuals will contain warnings and cautions and say, “You must look after the piece of cake by doing this”. I’m thinking the gremlins now “Don’t feed it after midnight or get it wet” otherwise bad things will happen. Sorry about that, slightly fatuous example, but a good illustration, I think. And ideally, if there’s any training materials associated with the piece of kit, is there a training needs analysis that shows how the training was developed? It’s very often in a TNA if it’s done well, there’s lots of good information in there. Even if it’s not quite for the same application that weighs in the piece of kit for, you could learn a lot from that kind of stuff

And finally, if all else fails, if you’ve got a legacy piece of kit, then you can physically inspect it. And if you can take it apart, put it back together again – do so. You might discover there’s asbestos in it. You might discover that lithium batteries or whatever it might be, fire hazards, flammable materials, toxic materials, you name it. there’s a lot of ways that we can get information about the subsystem. Ideally, we ask for everything upfront. Say, you know, if there’s any hazardous chemicals in there, then you must provide the hazard sheets and the hazard data in accordance with international or national standards and so on and so forth. But if you can’t get that or you haven’t asked for it, there are other ways of doing it, but they’re often time-consuming and not the optimal way of doing it.

So again, do think about what you need upfront and do ask for it. And if the contractor can’t supply exactly what you want, what you need, you then have to decide whether you could live with that, whether you could use some of these alternative techniques or whether you just have to say, “No, thanks. I’ll go to another supplier of something similar”. And I may have to pay more for it, but I’ll get a better-quality product that actually comes with some safety evidence that means I can actually integrate it and use it within my system. Sometimes you do have to make some tough decisions and the earlier we do those tough decisions the better, in my experience.

Copyright Statement

So that’s all the technical content. Just to say that all the text that’s in italics and in speech marks is from the standard, which is copyright free. But this presentation, and especially all the commentary and the added value, is copyright at the Safety Artisan 2020.

For More …

And if you want more videos like this, rest in the 882 series and other resources on safety topics, you can find them at the website www.safetyartisan.com. And you can also go to the safety artisan page at Patreon. that’s www.pateron.com and search for Safety Artisan – all one word.

End

So, that’s the end of the presentation and it just remains for me to say, thanks very much for watching and supporting the Safety Artisan. And I’ll be doing Task 205 system hazard analysis next in the series, look forward to seeing you again soon. Bye-bye, everyone.

End: Sub-System Hazard Analysis

You can find a free pdf of the System Safety Engineering Standard, Mil-Std-882E, here.

Categories
Work Health and Safety

Guide to the WHS Act

This Guide to the WHS Act covers many topics of interest to system safety and design safety specialists. The full-length video explains the Federal Australian Work Health and Safety (WHS) Act (latest version, as of 14 Nov 2020). Brought to you by The Safety Artisan: professional, pragmatic, and impartial.

This is the four-minute demo of the full, 44-minute-long video.

Recap: In the Short Video…

which is here, we looked at:

  • The Primary Duty of Care; and
  • Duties of Designers.

Topics: Guide to the WHS Act

In this full-length video, we will look at much more…

  • § 3, Object [of the Act];
  • § 4-8, Definitions;
  • § 12A, Exclusions;
  • § 18, Reasonably Practicable;
  • § 19, Primary Duty of Care;
  • § 22-26, Duties of Designers, Manufacturers, Importers, Suppliers & those who Install/Construct/Commission;
  • § 27, Officers & Due Diligence;
  • § 46-49, Consult, Cooperate & Coordinate;
  • § 152, Function of the Regulator; and
  • § 274-276, WHS Regulations and CoP.

Transcript: Guide to the WHS Act

Click here for the Transcript

Hi everyone and welcome to the Safety Artisan where you will find instructional videos like this one with professional, pragmatic and impartial advice which we hope you enjoy. I’m Simon and I’m recording this on the 13th of October 2019. So today we’re going to be talking about the Australian Federal Work Health and Safety Act and call it an unofficial guide or system or design safety practitioners whatever you want to call yourselves because I’m looking at the WHS Act from the point of view of system safety and design safety.

 As opposed to managing the workplace although it does that as well. Few days ago, I recorded a short video version of this and in the short video we looked at the primary duty of care and the duty particularly we look at the duty of designs. And so, we spent some time looking at that and that video is available on the freight on petrol on the safety artisan page at Patreon.com. It’s available at safetyartisan.com and you can watch it on YouTube. So just search for safety artisan on YouTube.

Topics

So, in this video, we’re going to look at much more than that. I say selected topics we’re not going to look at everything in the WHS Act as you can see there are several hundred sections of it. We’ll be here all day. So, what we’re going to look at are things that are relevant to systems safety to design safety. So, we look very briefly at the object of the act, at what it’s trying to achieve. Just one slight of definitions because there’s a lot of exclusions because the Act doesn’t apply to everything in Australia.

 We’re going to look at the Big Three involved. So really the three principles that will help us understand what the act is trying to achieve is:

  • what is reasonably practicable. That phrase that I’ve used several times before.
  • What is the primary duty of care so that sections 18 and 19. And if we jump to
  • Section 27 What are or who are officers and what does due diligence mean in a WHS setting?

So, if I step back one section 22 to 26 you know the duties of various people in the supply chain.  We cover that in the short session. So, go ahead and look at that and then moving on. There are requirements for duty holders to consult cooperate and coordinate and then a brief mention of the function of the regulator. And finally, the WHS Act enables WHS regulations and codes of practice. So we’re just mentioned that so those are the topics we’re going to cover quite a lot to get through. So that’s critical.

Disclaimer

So, first this is a disclaimer from the website from the federal legislation site and it does remind people looking at the site that the information put up there is for the benefit of the public and it’s free of charge.

 So, when you’re looking at this stuff you need to look at the relevance of the material for your purposes. OK, I’m looking at the Web site it is not a substitute for getting legal or appropriate professional advice relevant to your particular circumstances. So quick disclaimer there. This is just a way a website with general advice I think we’ll get we’ll get them and hence this video is only as good as the content that’s being present okay.

The Object of the Act

So, the object of the act then as you can say I’m quoting from it because I’m using quotation marks, so the main object of the act is to provide a balanced and nationally consistent framework for the health and safety of workers and workplaces.

 And that’s important in Australia because Australia is a federated state. So, we’ve got states and territories and we’ve got the federal government or the Commonwealth as it’s usually known and the laws all those different bodies do not always line up. In fact, sometimes it seems like the state and territories delight in doing things that are different from each other and different from the Commonwealth. And that’s not particularly helpful if you’re trying to you know operate in Australia as a corporation or you know you’re trying to do something big and trying to invest in the country.

 So, the WHS act of a model WHS Act was introduced to try and harmonize all this stuff. And you’ll see some more about that on the website. By the way and I’ve missed out on some objectives. As you can see, I’m not doing one subset B to H go to have a look at it online. But then in Section 2 The reminder is the principle of giving the highest level of protection against harm to workers and other persons as is reasonably practicable. Wonderful phrase again which will come back to okay.

Definitions

 Now there are lots of definitions in the act. And it’s worth having a look at them particularly if you look at the session that I did on system safety concepts, I was using definitions from the UK standard. Now I did that for a reason because that set of definitions was very well put together. So it was ideal for explaining those fundamental concepts where the concepts in Australia WHS are very different so if you are operating in Australian jurisdiction or you want to sell into an Australian jurisdiction do look at those definitions and actually being aware of what the definitions are will actually save you a lot of hassle in the long run.

 Now because we’re interested systems safety practitioners of introducing complex systems into service. I’ve got the definitions here of plant structure and substance. So basically, plant is any machinery equipment appliance container implement or to any component of those things and anything fitted or connected to any of those things. So, they go going for pretty a pretty broad definition. But bearing in mind we’re talking about plants we’re not talking about consumer goods. We’re not talking about selling toasters or electric toothbrushes to people. OK. There’s other legislation that covers consumer goods.

 Then when it comes to structure again, we’ve got anything that is constructed be fixed or movable temporary or permanent. And it might include things on the ground towers and masks underground pipelines infrastructure tunnels and mining any components or parts thereof. Again, a very broad definition and similarly substance any natural or artificial substance in whatever form it might be. So again, very broad and as you might recall from the previous session a lot of the rules for designers’ manufacturers, importers and suppliers cover plant structure and substances. So hence that’s why I picked just those three definitions out of the dozens there.

Exclusions

 It’s worth mentioning briefly exclusions: what the Act does not apply to. So, first, the Act does not apply to commercial ships basically. So, in Australia, the Federal legislation covering the safety of people in the commercial maritime industry is the Occupational Health and Safety Act (Maritime Industry) 1993, which is usually known as “OSHMI” applies to commercial vessels, so WHS does not. And the second exclusion is if you are operating an offshore petroleum or greenhouse gas storage platform and I think it’s more than three nautical miles offshore.

 But don’t take my word for that if you’re in that business go and check with the regulator NOPSEMA then this act the Offshore Petroleum and Greenhouse Gas Storage Act 2006 applies or OPGGS for short. So, if you’re in the offshore oil industry then you’ve got a separate Commonwealth act plot but those are the only two exceptions. So, where Commonwealth law applies the only things that WHS. does not apply to is commercial ships and offshore platforms I mentioned state and territory vs. Commonwealth. All the states and territories have adopted the model WHS system except Victoria which so far seems to be showing no interest in adopting WHS.

 Thanks, Victoria, for that. That’s very helpful! Western Australia is currently in process of consultation to adopt WHS, but they’ve still got their current OH&S legislation. So just note that there are some exclusions there. OK so if you’re in those jurisdictions then WHS does not apply. And of course, there are many other pieces of legislation and regulation that cover particular kinds of risk in Australia. For example, there’s a separate act called ARPANS that covers ionizing a non-ionizing radiation.

There are many other acts that cover safety and environmental things. Let’s go back one when I’m talking about those specific acts. They only apply to specific things whereas WHS act is a general Act applies to everything except those things that it doesn’t like to write move on.

So Far As is Reasonably Practicable

Okay now here we come to one of these three big ticket items and I’ve got two slides here. So, in this definition of reasonably practicable when it comes to ensuring health and safety reasonably practicable means doing what you are reasonably able to do to achieve the high standards of health safety in place.

 Considering and weighing up all the relevant matters; including, say, the first two we need to think about the likelihood of a hazard or risk. How likely is this thing to occur this potential threat to human health? And what’s the degree of harm that might result from the hazard or risk. So, we’ve got a likelihood and degree of harm or severity. So, if we recall the fundamental definition of risk is that it’s though it’s the factor of those two things taken together. So, this first part we’re thinking about what is the risk?

 And it’s worth mentioning that hazard is not defined in the Act and risk is very loosely defined. So, the act is being deliberately very broad here. We’re not taking a position on or style of approach to describing risks, so to the second part.

Having thought about the risk now we should consider what the person PCBU or officer, whoever it might be, ought reasonably to know about the hazard or risk and the ways of eliminating or minimizing the risks. So, what we should know about the risk and the ways of dealing with it of mitigating it of controlling and then we’ve got some more detail on these ways of controlling the risk.

 We need to think about the availability and suitability of ways to eliminate or minimize the risk. Now I’m probably going to do a separate session on reasonably practicable because there is a whole guidebook on how to do it. So, we’ll go through that and at some stage in the future and go through that step by step about how you determine availability and suitability et cetera. And so, once you get into it it’s not too difficult. You just need to follow the guidelines which are very clear and very well laid out.

 So having done all of those things, after assessing the extent of the risk and the available ways of controlling it the we can then think about the cost associated with those risk controls and whether the cost of those controls is grossly disproportionate to the risk. As we will see later, in the special session, if the cost is grossly disproportionate to the risk reduction then it’s probably not reasonable to do it. So, you don’t necessarily have to do it but we will step back and just look at the whole thing.

So, in a and b we’re looking at the likelihood and severity of the risk so and we’re (quantifying or qualitatively) assessing the risk. We’re thinking about what we could do about it, how available and suitable are those risk controls, and then putting it all together. How much will it cost to implement those risk controls and how reasonably practicable to do so. So what we have here is basically a risk assessment process that leads us to a decision about which controls we need to implement in order to achieve that ‘reasonably practicable’ statement that you see in so many parts of the act and indeed it’s also in the definition itself.

 So, this is how we determine what is reasonably practicable. We follow a risk assessment process. There is a risk assessment Code of Practice, which I will do a separate session on, which gives you a basic minimum risk assessment process to follow that will enable us to decide what is reasonably practicable. Okay, quite a big topic there. And as I say we’ll come back and do a couple more sessions on how to determine reasonably practical, so moving on to the primary duty of care we covered in the short session.

The Primary Duty of Care

 So I’m not really going to go through this again [in detail] but basically our primary duty is to ensure so far as is reasonably practicable the health and safety of workers, whether we’ve engaged them whether we’ve got somebody else to engage them or whether we are influencing or directing people carrying out the work. We have a primary duty of care if we’re doing any of those things. And secondly, it’s worth mentioning that the person conducting a business or undertaking the PCBU must ensure the health and safety of other people. Say, visitors to the workplace are members of the public who happen to be near the workplace.

 And of course, bearing in mind that this law applies to things like trains and aircraft if you have an accident with your moving vehicle or your plant you could put people in danger – in the case of aeroplanes anywhere in Australia and beyond. So, it’s not just about the work, the workers in the workplace. With some systems, you’ve got a very onerous responsibility to protect the public depending on what you’re doing. Now for a little bit more detail that we didn’t have in the short session. When we say we must ensure health and safety we’re talking about the provision and maintenance of a safe work environment or safe plant structures or safe systems of work talking about safe use handling and storage of structures and substances.

 We’re talking about adequate facilities for workers that are talking about the provision of information, training, instruction or supervision. Those workers and finally the health of workers and conditions of the workplace are monitored if need be for the purpose of preventing illness or injury. So, there should be some general monitoring of health and safety-related incidents. And if you’re dealing with certain chemicals or are you intentionally exposing people to certain things you may have to conduct special monitoring looking for contamination or poisoning of those people whatever it may be. So, you’ve got quite a bit of detail there about what it means to carry out the primary duty of care.

 And this is all consistent with the duties that we’ve talked about on designers, manufacturers, importers, and suppliers and for all these things there are codes of practice giving guidance on how to do these things. So, this whole work health and safety system is well thought through, put together, in that the law says you’ve got to do this. And there are regulations and codes of practice giving you more information on how you can fulfil your primary directive and indeed how you must fulfill your primary duty.

 And then finally there’s a slightly unusual part for at the end and this covers the special case where workers need to occupy accommodation under the control of the PCBU in order to get the job done. So you could imagine if you need workers to live somewhere remote and you provided accommodation then there are requirements for the employer to take care of those workers and maintain those premises so that they not exposed to risks.

 That’s a big deal because she might have a remote plant, especially in Australia which is a big place and not very well populated. You might be a long way away from external help. So if you have an emergency on-site you’re going to have to provide everything (not just an emergency you need to do that anyway) but if you’ve got workers living remotely as often happens in Australia you’ve got to look after those workers in a potentially very harsh environment.

And then finally it’s worth mentioning that self-employed persons have got to take care of their own health and safety. Note that a self-employed person is a PCBU, so even self-employed people have a duty of care as a PCBU.

The Three Duties

OK, sections 22 to 26. Take that primary duty of care and elaborate it for designers and manufacturers, importers and suppliers and for those installing constructing or commissioning plant substances and structures. And as we said in the free session all of those roles all of the people BCBS is doing that have three duties they have to ensure safety in a workplace and that includes you know designing and manufacturing the thing and ensuring that it’s safe and meets Australian regulations and obligations.

 We have a duty to test which actually includes doing all the calculations analysis and examination that’s needed to demonstrate safety and then to provide needed information to everybody who might use or come into contact with the system so those three duties apply consistently across the whole supply chain. Now we spent some time talking about that. We’re going to move on OK, so we are halfway through. So, a lot to take in. I hope you’re finding this useful and enjoying this. Let’s move on. Now this is an interesting one.

Officers of the PCBU

Officers of the PCBU have additional duties and an officer of the PCBU might be a company director. That’s explicitly included in the definition. A senior manager somebody who has influence. Offices of the PCBU must exercise due diligence. So basically, the implied relationship is you’ve got a PCBU, you’ve got somebody directing work whether it be design work manufacturing operating a piece of kit whatever it might be. And then there are more senior people who are in turn directing those PCBUs (the officers) so the officers must exercise due diligence to ensure that the PCBUs comply with their duties and obligations.

Sections 2 to 4 cover penalties for offices if they fail. I’m not going to discuss that because as I’ve said elsewhere on the Safety Artisan website, I don’t like threatening people with penalties because I actually think that results in poor behavior, it actually results in people shirking and avoiding their duties rather than embracing them and getting on with it. If you frighten people or tell them what’s going to happen to them, they get it wrong. So, I’m not going to go there. If you’re interested you can look up the penalties for various people, which are clearly laid out. We move on to Section 5.

Due Diligence

 We’re now talking about what is due diligence in the context of health and safety. OK, I need to be precise because the term due diligence appears in other Australian law in various places meaning various things, but here this is the definition of due diligence within the WHS context. So, we’ve got six things to do in order to demonstrate due diligence.

So, officers must acquire and keep up to date with knowledge of work health and safety matters obligations and so forth. Secondly, officers must gain an understanding of the nature of the operations of the piece and risks they control.  So, if you’re a company director you need to know something about what the operation does. You cannot hide behind “I didn’t know” because it’s a legal requirement for you to do it. So that closes off a whole bunch of defenses in court. You can’t plead ignorance because ignorance is, in fact, illegal and you’ve got to have a general understanding of the hazards and risks associated with those operations. So, you don’t necessarily have to be up on all the specifics of everything going on in your organization but whatever it is that your organization does. You should be aware of the general costs and risks associated with that kind of business.

Now, thirdly, we are moving on basically C D E and F refer to appropriate resources and processes, so the officers have got to ensure that PCBUs have available and use appropriate resources and processes in order to control risks. OK so that says you’ve got to provide those resources and processes and there is supervision, or some kind of process or requirement to say, yep, we put in let’s say a safety management system that ensures people do actually use the stuff that they are supposed to use in order to keep themselves safe.

 And that’s very relevant of course because often people don’t like wearing, for example, protective personal protective equipment because it’s uncomfortable or slows you down, so the temptation is to take it off. Moving on to part D we’re still on the appropriate processes; we must have appropriate processes for receiving and considering information on incidents, hazards and risks. So again, we’ve got to have something in place that keeps us up to date with the incidents, hazards and risks in our own plants and maybe similar plants in the industry and, we need a process to respond in a timely way to that information.

 So, if we discover that there is a new incident or hazard that you didn’t previously know about. We need to respond and react to that quickly enough to make a difference to the health and safety of workers. So again as another that sort of works in concert with part B doesn’t it. In part A and B we need to keep up to date on the risks and what’s going on in the business and part A, we need to ensure that the PCBU has processes for compliance with any duty or obligation and follows them again to provide that stuff.

In the system safety world, often the designers will need to provide the raw material that becomes those processes. Or maybe if we’re selling the product, we sell a product with the instruction manual with all the processes that could be required.

And then finally the officers must verify the provision and use of these resources and processes that we’ve been talking about in C D an E. So, we’ve got a simple six-point program that comprises due diligence, but as you can see it’s very to the point and it’s quite demanding. There’s no shirking this stuff or pretending you didn’t know and it’s I suspect it’s designed to hang Company directors who neglect and abuse their workers and, as a result, harm happens to them.

But I mean ultimately let’s face it this is all good common-sense stuff. We should be doing this anyway. And in any kind of high-risk industry we should have a safety management system that does all of this and more. These are only the minimum required for all industries and all undertakings in Australia. OK let’s move away from the big stick. Let’s talk about some sort of cozy, softer stuff.

Consult, Cooperate and Coordinate

If you are a duty holder, if you’ve got a duty of care to people as a PCBU or an officer, you must consult, cooperate and coordinate your activities with all other offices and bases be used.

You have a duty in relation to the same matter. So perhaps you are a supplier of kit and you get information from the designer or the manufacturer with the updates on safety or maybe they inform you of problems with the kit. You must pass that on. Let’s imagine you’re introducing a complex system into service. There are going to be lots of different stakeholders, and you all must work together in order to meet WHS obligations. So, there’s no excuse or trying to ask the buck to other people.

That’s not going to work if you haven’t actively managed the risk, as you are potentially already doing something illegal and again, we won’t talk about the penalties of this. We’re just talking about the good things we’re expected to do. So, we’re trying to keep it positive. And you’ve got a duty to consult with your workers who either carry out work or who are likely to be directly affected by what’s going on and the risks. Now, this is a requirement that procedures in Sections 2 and 3, but of course we should be consulting with our workers because they’ve often got practical knowledge about controlling risks and what is available and suitable to do so, which we will find helpful.

So, consulting workers is not only a duty it’s actually a good way of doing business and doing business efficiently so moving on to section 152.

The Regulator

There are several sections about the regulator, but to my mind, they don’t add much. So, we’re just going to talk about Section 152, which is the functions of a regulator and the regulator has got several functions. So, they give advice and make recommendations to the relevant minister or Commonwealth Minister of the government. They monitor and enforce compliance with the act.

 They provide advice and information to duty holders and the community they collect analyse and publish statistics. They’re supposed to foster a co-operative, consultative relationship in the community to promote and support education and training and to engage in and promote and coordinate the sharing of information. And then finally they’ve got some legal duties with courts and industrial tribunals, and here’s the catch-all, any other function conferred on the regulator by the Act. If we look at the first six the ones that I’ve highlighted there are a number of regulators in Australia and because of the complexity of our federal government system, we’ve got.

 It’s not always clear which regulator you need to deal with and not all regulators are very good at this stuff. I have to say having worked in Europe and America and Australia, for example on Part D. Australian regulators are not very good at analyzing and publishing statistics in general. Usually, if you want high-quality statistics from a regulator, you’re usually better off looking at a European regulator in your industry or an American regulator. The Aussie ones don’t seem to be very good at that, in general.

There are exceptions. NOPSEMA, for example in the offshore world, are particularly good. But then you would expect because of the inherent dangers of offshore operations. Otherwise, I’ve not been that impressed with some of the regulators. The exception to that is Safe Work Australia. So, if you’re looking for advice and information, statistics, education and training and sharing of information then Safe Work Australia is your best bet. Now ironically Safe Work Australia is not a regulator.

Safe Work Australia

They are a statutory authority and they created, in consultation with many others I might say, they created a model WHS Act the model regulations and the Model Codes practice. So, if you go on their website you will find lots of good information on there and indeed I tend to look at that in order to find information to post on safety artisan. So, they’ve got some good WHS information on there. But of course, the wherever you go look at their site you must bear in mind that they are not the regulator of anything or anyone. So, for you’ve also got to go and look at the find the relevant regulator to your business or undertaking and you’ve got to look at what your regulator requires you to do.

 Very often when it comes to looking at guidance your best bet is safe work Australia okay.

Regulations and Codes of Practice

I’ve mentioned regulations and codes of practice. Basically, these sections of the act enable those codes of practice and regulations so the Minister has power to approve Commonwealth codes of practice and similarly state and territory ministers can do the same for their versions of WHS. This is very interesting and we’ll come back to relook at codes of practice in another session. An approved code of practice is admissible in court as evidence, it’s admissible as the test of whether or not a duty or obligation under the WHS Act has been complied with.

 And basically, the implication of this is that you are ignorant of codes of practice at your peril because if something goes wrong then codes of practice are what you will be judged against at minimum. So that’s a very important point to note and we’ll come back to that on another session.

Next, Codes of Practice and then regulation-making powers. For some unknown reason to me, the Governor-General may authorize regulations. I mean that doesn’t really matter. The codes of practice and the regulations are out there, and the regulations are quite extensive.  I think six hundred pages. So, there’s a lot of stuff in there. And again, we’ll do a separate session on WHS regulations soon OK.

That’s All Folks!

I appreciate we’ve covered quite a lot of ground there but of course, you can watch the video as many times as you like and go and look at the Act online. Mentioning that all the information I’ve shown you is pretty much word for word taken from the federal register of legislation and I’m allowed to do that under the terms of the license.

Creative Commons Licence

 And it’s one of those terms I have to tell you that I took this information yesterday on the 12th of October 2019. You should always go to that website to find the latest on Commonwealth legislation (and indeed if you’re working on it state or territory jurisdiction you should go and see the relevant regulator’s legislation on their site). Finally, you will find more information on copyright and attribution at the SafetyArtisan.com website, where I’ve reproduced all of the requirements, which you can check. At the Safety Artisan we’re very pleased to comply with all our obligations.

Now for more on this video, you may have seen it on Patreon on the Safety Artisan page or you may have seen it elsewhere, but it is for sure available Patreon.com/SafetyArtisan. Okay. So, thank you very much for listening and all that remains for me to do is to sign off and say thanks for listening and I look forward to presenting another session to you in a month’s time. Take care.

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