How do you tell if there is a possibility of a gas explosion?

Answer 1

Any time natural gas fills an area , in the presence of oxygen (at a concetration typical in air), you have a risk of a gas flare up.

Any hissing sound near a gas line is an indication. Also, while natural gas itself is odorless, during processing, an garlic-like or rotten-egg scent is added to the gas especially so you can detect it. If you smell this scent, that's evidence of a gas leak.

You can also test to see if a gas line is leaking by gently mixing dish washing liquid into water, so there are very few bubbles, then "painting" this on the part of the gas line you want to test. If bubbles form, that too is evidence of a gas leak.

If you even think you may have a gas leak, here's what to do:

1. Get all people and pets out of the area. Outside the house if you're not sure how much gas there is.
2. DO NOT USE A CELL PHONE, CORDLESS PHONE OR FLASHLIGHT INSIDE THE ENCLOSURE! DO NOT USE MATCHES! DO NOT FLICK ELECTRICAL SWITCHES SUCH AS LIGHT SWITCHES! AND DO NOT SMOKE!
3. Once outside, call the gas company (0800 111 999 for Transco in the UK) or the fire dept.This is considered an emergency.
4. If you know where the gas cut-off is for the house, cut off the gas -- from OUTSIDE only.
5. Do as directed by emergency response crews.

Most gas leaks do not result in explosion, as it takes a lot of gas accumulating in one place to generate that much energy. However, better safe than sorry.

A more common risk apart from a gas leak is if an appliance is left on unlit. If this has happened you should switch of the appliance, open windows and avoid doing anything which might create a spark, see point 2 above, until the gas has dissipated.