9 replies to this topic

[Bob Twells]

Following the recent explosion at a fertiliser plant in Texas (http://www.bbc.co.uk...canada-22195866), I came across this follow up article about the explosive (or not) properties of Ammonium Nitrate:

http://boingboing.ne...tml#more-225164

 

A nice simple read for the layperson like me

[Sparky]

Interesting read Bob.

 

I've always wondered about its stability as they use it in  the US a lot to make rocket propellant instead of Ammonium Perchlorate and I never felt that it was all that sensible.

 

What I really don't understand is how they license production/storage of any chemical with "risks" right next to civilian housing! Surely the plant should be in the middle of nowhere.

[digger]

mmmm

 

Sparky the problem which is often the case. The plant was there first in the middle of nowhere and the housing estate was built up around it.

 

We have a number of plants around the world that have been completely encircled by housing over the last 50 years. This is down to local goverment allowing the housing rather than them allowing the chemical plant.

 

Most oxidisers are very stable in their own right.

 

D

[Vic]

What I don't understand is, with evidence from previous instances of this type. Where the fire has been raging for some time before the detonation, in that they had well over an hour to get people clear, rather than fight the fire. Why were there no evacuation plans put in place as soon as the fire broke out.

[Peret]

Ammonium nitrate normally needs a strong shock to set it off, but presumably will also decompose with excessive heat, thus furnishing the necessary shock for the rest of it. Ammonium Pechlorate will also explode if it gets hot enough - Pepcon, anyone?

http://classiclasveg...years-gone.html

[pyrotrev]

What I don't understand is, with evidence from previous instances of this type. Where the fire has been raging for some time before the detonation, in that they had well over an hour to get people clear, rather than fight the fire. Why were there no evacuation plans put in place as soon as the fire broke out.

Good point Vic, sounds like the local fire service hadn't done their homework. There was a big agricultural wholesalers near where I used to live who held up to 200 tons of AN at some times. The local fire service had done a survey there, and their plan in the event of a fire was to evacuate everyone within 1.5 miles, sit back and watch   

[Sparky]

I've just read that the company had a history of poor risk assessment planning. Clearly the local residents had never been warned that if there was a fire they should evacuate. The video of the Dad with his daughter filing the fire from what looked to be about 1/4 mile max said it all. If he had known the risk he would have been several miles away.

[Sparky]

Apparently AP is only classed as an explosive if it is <15u particle size. Not sure what mesh size that would be but it sounds very fine indeed.

[digger]

15 micron or 15 millionths of a metre

[dannytsg]

Nice article, thanks for that