Positive air shutdown installation

wreedsvt said:

Wow, what do you do that requires this? Just curious...

Click to expand...

I have to drive to oilfield sites, among other places....

To gain access to oilfield sites it is usually mandatory to have a way to shut down the engine if combustible gases become mixed in the environment. A positive air shutoff is needed for anyone with a diesel engine that may come in contact with natural gas, propane, or any other flammable gasses. A small leak of flammable gas is likely to cause a diesel engine to "run away", causing catastrophic damage to the engine, and surrounding area as it explodes. If it explodes on a site with hazardous atmosphere like a refinery, you would most likely make the 6 o'clock news. Diesel engines will run on any fuel available even when the key is removed. Once a diesel engine gets a supply of flammable gas in the air, it will run indefinitely or to the point of catastrophic failure. The only way to prevent and stop this is to shut off the air supply to the engine, starving it of air born fuel.

However in the crappy link I posted to youtube above, none of the vehicles appear to be on oilfield sites but they still had runaways. This is because diesels can also run on their own oil. For example, if your turbo started leaking in your driveway the motor would rev past the red line until it was starved of oil and it seized up solid and/or had its own coming out party.