In this 45-minute session, I look at System Hazard Analysis with Mil-Std-882E. SHA is Task 205 in the Standard. I explore Task 205’s aim, description, scope, and contracting requirements.
I also provide commentary, based on working with this Standard since 1996, which explains SHA. How to use it to complement Sub-System Hazard Analysis (SSHA, Task 204). How to get the maximum benefits from your System Safety Program.
Using Task 205 effectively is not just a matter of applying it in number order with the other Tasks. We need to use it within the Systems Engineering framework. That means using it top-down, to set requirements, and bottom-up to verify that they are met.
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 with Mil-Std-882E
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, Task 205 in the Mil-Std-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 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 bring to your attention and emphasize.
Within Task 205, Purpose. We’ve got four purpose slides for this one. Verify subsistent compliance and recommend necessary actions – fourth one there. And then in the middle of the sandwich, we’ve got the 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 a different emphasis to 204, which was 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 document, as usual, looking at hazards and mitigations, or controls, in the integrated system design, including software and human interface. We must 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.
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…
The End
You can find a free pdf of the System Safety Engineering Standard, Mil-Std-882E, here.
Learn safety engineering with me, an industry professional with 25 years of experience, I have:
•Worked on aircraft, ships, submarines, ATMS, trains, and software;
•Tiny programs to some of the biggest (Eurofighter, Future Submarine);
•In the UK and Australia, on US and European programs;
•Taught safety to hundreds of people in the classroom, and thousands online;
•Presented on safety topics at several international conferences.