Major Incident Planning and Support (MIP+S) Level 3

100 videos, 6 hours and 37 minutes

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Loading and unloading dangers

Video 93 of 100
4 min 54 sec
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Okay, so here we have the rail siding and two or three times a week, we have 18 railcars that come in here, and we offload actually extremely flammable material, so the danger is that whilst you are off-loading, you have a failure somewhere that leads to a loss of containment. The railcars are all linked together, so even though they are split eight and eight, you are offloading eight railcars at any one time. They are offloaded overnight, so typically the train comes in around four or five o'clock in the evening, the material is offloaded overnight, and then the train goes out empty the following morning. Whilst you are offloading, the most vulnerable point is the flexible hose connection because each railcar has a flexible hose connecting as part of the offloading manifold. So they are regularly inspected, they are regularly in-tested, they are chucked away and replaced every five years, even though there is nothing wrong with them perhaps. They are dry brake, so if they were to actually come off then nothing can come out of the end of the hose, but clearly, something can continually come out of the railcar. You could have a split in the hose and you could have a leak that way, so the main issue here is a loss of containment.

First and foremost, you don't want the situation to escalate, so if you got flammable material leaking from a railcar, then it has got quite a good chance of finding an ignition source. Now, ignition sources are controlled very, very strictly on this site. Obviously, no smoking, we have to wear the vapour alarm so that we may well contact somewhere where there could be vapour, in which case these alarms will go off. If you have lost containment, then what you don't want is you don't want a source of ignition because if you get a source of ignition, then you have got potential for firstly, a flash fire, and then if you don't flash off all of the volatile material, you could be left with a pool fire, and if you are left with a pool fire, you have got material being fed to that fire by the leaking railcar, so you want to try and mitigate those things as soon as possible. The issue with this particular situation is you are quite close to the boundary, the southern boundary of the site, so therefore we have a public footpath running down the side which we can't control any ignition sources. We don't know if people are smoking walking up and down there, so that is a concern.

In terms of fighting the incident itself, control the incident as much as possible, stop material going to the environment if you can get there, and you may well be able to block off railcars on either side, so you can stop the potential for the whole eight cars dropping on the floor and you can isolate it to one car. Even so, even if you are going to do that, if it's the start of the offloading procedure, then there is 100 tons in that one railcar, so that is 100, effectively 100,000 litres or 120,000 litres so that is going to be quite a big spill and quite a big incident, so you need to mitigate that pretty soon. Sound the fire alarm, get the emergency services involved, and try and prevent escalation is what our role would be in that incident.

If it's during the day, then the likelihood is that those railcars are... If there are railcars here, they're probably empty. So they don't stay here that long, they come in in the evening, offload overnight and then go out the following morning, so there often isn't actually railcars here. If it's at night and you are actually offloading, then obviously you would stop offloading and make it safe as possible. I doubt very much whether we would actually remove it from site unless this particular area was affected by the incident or there was the potential for this area to become affected by the incident. The key thing is to make it safe as possible, so shut everything down, turn everything off, and make the area safe.

Another scenario is that we are obviously offloading this material into a tank, and there is the potential there for overfilling that tank, and if that was to happen, you would have again, you would have a loss of containment, the material could come over the top of the tank, and that could lead to a more serious incident in the sense that yet again, if you got material outside of where it should be, I.e. You have lost containment, the next step is it is likely to find an ignition source, and then we are looking at bonfires, pool fires, vapour cloud explosions, all the sorts of things that you don't want to happen.