Pragmatic 13A: Safety, Safety Everywhere Follow-up 1

7 October, 2014


Follow up (Part A) to Safety, Safety Everywhere with Fire Extinguishers being fitted to the wrong spot in a Nuclear Reactor and the dangers of Nitrogen purging.

Transcript available
This is Pragmatic Follow-Up Part A for Episode 13, Safety, Safety Everywhere. I'm Jon Chidjie and joining me is Vic Hudson. How you doing Vic? I'm good Jon, how are you? Very good, thank you. So a friend of the show, David Legate, sent through a very interesting link. I was going to say funny and you know I say I have this expression where I say, "Oh you know the funny thing is..." and then I say that, "Oh actually no, it's not funny." Well it isn't. This is one of those situations. So it's an article about a nuclear power plant and what they did is in Europe and they were fitting as a part of a safety initiative they were fitting more fire extinguishers and when they're fitting the fire extinguishers you've got to hang them on the wall. Well what they did when they actually mounted on the wall is that because in order to mount it, because the fire extinguisher is quite heavy so what you want to do is you want to put an anchor on the wall. Well, they put an anchor on the wall, but the wall that they put it on just happened to be the outer protective shell, the containment shell, for the outer reactor. But you're not supposed to be... Whoops! Dear me. Anyhow, look, there was no incident beyond the fact that there was a... Yeah, Yeah, I mean, nothing actually went wrong, but it was a breach of the safety regulations. I had to patch it up and do a whole bunch of little, you know, remedial things to fix it up afterwards. But what it brought to the forefront of my mind was that it's an interesting effect where the act of intending to improve the safety of in a situation can actually in itself create a safety problem. Yeah, it's worth pondering, I think, because, you know, we take these sorts of precautions, right? Let's say it's long sleeve shirt long pants and we're just talking about this before the show and you know that that's all well and good and great and lovely. But you know what if what if it's the middle of summer and that causes to have a heat stroke. You know it's like one precaution creates a new safety hazard. It's a trade off. It is a trade off exactly so you know I think it's worth thinking about so not just what can we do to improve the safety net in this situation but also what exactly. that I choose to do, will that affect my safety in other ways? So it's worth pondering and to the people over there mounting fire extinguishers, you know, bad. Think it through next time. There we go. So anyway, and actually another example, just thinking about regarding the heat and skin cancer is I was out on site just recently and when I was out on site, you got to wear a hard hat and hard hats of course are notoriously not exactly like a wide brim hat so if you're out in the Sun you know and you're just wearing one of these and you're not wearing sunscreen and so on well that's a problem so what do you do right? Someone come up with this idea of a sun brim that you fit to the hard hat and sort of like pops around the outside and it gives you the equivalent of a of a nice wide brim sun hat and that's great but the number of people that don't do it is ridiculous I mean they've got these things hanging up in the safety the PPE shed this and you know people just don't put them on their hard hats I don't know why all it takes is like five minutes out of your way to go grab one put one on and then it's on for the rest of your time using that hard hat so why not anyway little thing but still all right next thing is had a an email from a friend of the show Tristan Lostra I hope I'm pronouncing right Tristan? And it was a link about a few things but the first one was about Space Shuttle Columbia's first victims. There's a link in the show notes to this article it is a very good read if you're interested in safety and cause and effect and it's it's kind of kind of scary actually because everyone remembers Columbia from when it burned up in re-entry in 2003 very tragically a horrible accident. However, in 1981, long before that, there was an incident where John Bornstadt, Forrest Cole, they died on the day of the incident and Nicholas Mullen suffered for a decade and a half after the incident before he died with physical and psychological issues as a direct result of the incident. So what happened was it was a nitrogen purge. Now nitrogen purging is relatively common in industry, certainly in oil and gas and also in the you know with the space shuttle because when they're dealing with you know liquid oxygen, hydrogen and so on, you know they're very, very explosive gases. So what you want to do is you want to make sure that those compartments are completely clear before you mix in normal air. Okay. So the idea is you purge it with nitrogen. So you fill up with pure nitrogen. So people think that nitrogen is harmless, right? It's because 78% of the Earth's atmosphere is nitrogen. So you think, yeah, okay, nitrogen is safe, right? It's essentially an inert gas and it's most common form, which is N2. It's actually a trivalent bond, a triple bond. So it's very difficult to break that bond. Hence it doesn't react with very many things. And because it's readily available, there's so much in the atmosphere, it's easy to extract. So therefore it can be used to expel any other hazardous gases, which is why I say purging is perfect. The problem is, and this was the case with Columbia, is that because nitrogen displaces oxygen we need oxygen to breathe. So when there's low oxygen in our lungs, we stop creating CO2. And if there's no oxygen, you can't make CO2, obviously. Hence, there's no trigger in our brain to tell us that we're suffocating. We just pass out from low oxygen. Now I guess what I wanted to touch on this, and on nitrogen specifically, is that in the oil and gas industry, it's also common as a safety practice to purge with nitrogen. So let's say that you've got a pig launcher and you're about to pig a line or you've just pig the line, well you know you're going to inject that potentially you could inject that with nitrogen to get rid of any hydrocarbons in there such that when you opened up the pig to remove it for cleaning purposes there's going to be no issues, no chance of explosion. Right well here's the here's some interesting statistics for you about nitrogen. In the decade from 92 to 2002 I don't have more recent statistics sorry but that's all I could find, there were 85 separate incidents and this is the in the United States alone 80 people were killed and 50 people were seriously injured so nitrogen and nitrogen purging it's intended to improve safety but it's actually quite dangerous and people underrate... interesting... sorry? I said interesting? yeah it is it's it's interesting because like I said it's the act of trying to make something safe which sort of dovetails into the my first the first comment feedback from David is that the act of trying to render something safe actually creates a hazard. Anyway so worth thinking about if you're in that industry or certainly yeah perhaps there are too many listeners in that situation but still I think it's interesting. Another side note about Tristan as well that I didn't realize is he actually worked for Gas Detection Australia which although they're not in hazardous area detection so like portable meters and stuff they do a lot of single fixed location detectors in the lingo they call it fixed point for short and he was telling me that there's two biggest money spinners were car park carbon monoxide and cold room carbon dioxide sensors but with car parks what they do is apparently they hook up the ventilation fan variable speed drives. So rather than running the fans on full speed, what they'll do is they'll run them based on the proportion of carbon monoxide. So as the proportion of carbon monoxide increases, they'll increase the speed of the fans to draw in fresh air or to expel bad air. And that saves them money because then they don't have to run them at full tilt all the time, which is rather interesting and typical, right? So determine the level of carbon monoxide before people start getting sick and then we'll run the fans just before we reach that point. Yeah, that's like typical, lovely. I don't think it's-- - They can get a headache, but we don't want them to get sick. - Yeah, exactly. Anyway. Anyway, so yeah, and he was also personally developed, personally involved in the development of a CO2 sensor at one point in his career, which is sounds pretty cool to me. Anyway, and found plenty of carbon dioxide leaks in beer lines because people didn't install them correctly. So again, very interesting. So thank you very much to David and Tristan for that follow-up, much appreciated.
Duration 9 minutes and 14 seconds Direct Download

Show Notes

Related Links:

Premium supporters have access to high-quality, early released episodes with a full back-catalogues of previous episodes


Vic Hudson

Vic Hudson

Vic is the host of the App Story Podcast and is the developer behind Money Pilot for iOS.

John Chidgey

John Chidgey

John is an Electrical, Instrumentation and Control Systems Engineer, software developer, podcaster, vocal actor and runs TechDistortion and the Engineered Network. John is a Chartered Professional Engineer in both Electrical Engineering and Information, Telecommunications and Electronics Engineering (ITEE) and a semi-regular conference speaker.

John has produced and appeared on many podcasts including Pragmatic and Causality and is available for hire for Vocal Acting or advertising. He has experience and interest in HMI Design, Alarm Management, Cyber-security and Root Cause Analysis.

Described as the David Attenborough of disasters, and a Dreamy Narrator with Great Pipes by the Podfather Adam Curry.

You can find him on the Fediverse and on Twitter.