Fridge explosion

[Arefbee]

Not that the press ever gets it wrong... but this article indicates an owner was injured when the ammonia in his fridge found a source of ignition.

Fiery RV explosion leaves Bridgewater man in critical condition | NJ.com

Any way you look at it, I feel sorry for the guy and his injuries. I'm guessing root cause is improper safety techniques applied to keeping explosive gases from ignition sources. PPDs may not have been present based on injuries described.

[Oakman]

That's really a shame. It sounds to me like a shade tree mechanic working on something he was clueless about and paid the price.

[gasman6674]

I have never seen ammonia explode. It will burn if the ignition source is hot enough but not expode. Probaly hooked it up to a grill bottle without a regulator

[Dodge Guy]

As soon as it is deemed necessary to use a flame on an RV fridge for repair, it is time for a new fridge!

[RPAspey]

Originally Posted by gasman6674

I have never seen ammonia explode. It will burn if the ignition source is hot enough but not expode. Probaly hooked it up to a grill bottle without a regulator

I was thinking the same thing. Or he never really disconnected the gas. The evaporation fridge does have hydrogen in the system, but from what I understand, it isn't a lot.

[Batts-toy]

Originally Posted by gasman6674

I have never seen ammonia explode. It will burn if the ignition source is hot enough but not expode. Probaly hooked it up to a grill bottle without a regulator

I have worked with ammonia on a larger scale for 47 years and yes it can explode or flash burn. You will often see ammonia being transported and it will say on the trailer non-flammable this is because the range of oxygen to ammonia where it will burn/explode is very small but if the mix is at the right point and finds ignition it will explode and quite violently. I am a Chemical emergency responder with incident command training (have been for many years), I have seen rail cars of ammonia explode that developed a leak in train wrecks, I have seen seen (in my training sessions) buildings explode killing responders where the leak in a building meets just the right mix. Get a professional to do your refrigeration work please.

[RPAspey]

thanks! I learn something everyday.

[Batts-toy]

Originally Posted by RPAspey

thanks! I learn something everyday.

Your welcome, I can elaborate a little more on what 'may have' happened with the injured man with the fridge he may have been heating the tubing trying to melt solder. It's called a 'blevey', when ammonia (or hydrogen for that matter) is heated it expands and the pressure inside goes up. There are tables where you can look up temperature/pressure ratios on different types of gasses, if the temperture goes up in the vessel the pressure goes up with it, if the pressure gets high enough it will exceed the vessels pressure rating and blow it open (blevey), as the gasses exit the vessel it will most likely ignite and thus burning whatever or whoever is near by. I retired last January and am now working part time for the same company as a trainer and consultant.

[Batts-toy]

One more thing then I will shut up, the fridge works on exactly the principle I just went over. a flame heats the hydrogen which in turn heats the ammonia causing the pressure to go up. When the ammonia goes through a restrictor valve the pressure takes a quick drop lowering the ammonia temperature quite rapidly which in turn cools the fridge. When a flame is not being used a compressor runs to create the pressure change. Air conditioners work the same way.

[Jfwoodland]

Originally Posted by Batts-toy

It's called a 'blevey', when ammonia (or hydrogen for that matter) is heated it expands and the pressure inside goes up.

BLEVE = Boiling Liquid Expanding Vapor Explosion

[DDC]

When I was an apprentice in the sixties my journeyman use to say 'a little knowledge is a very dangerous thing'.

[Batts-toy]

Originally Posted by Jfwoodland

BLEVE = Boiling Liquid Expanding Vapor Explosion

Welcome to the forum and Thanks for the clarification and spelling.

[Batts-toy]

Originally Posted by DDC

When I was an apprentice in the sixties my journeyman use to say 'a little knowledge is a very dangerous thing'.

I can deal with hundreds of tons of Anhydrous Ammonia on a daily basis, but I am not about to try and repair my own fridge or AC. It's not worth the danger involved get a professional.