On Mon, 02 Jul 2007 01:58:33 +0100, John Rumm wrote:

Brian Sharrock wrote:

M - Methane
I - Illuminating Gases (old term for natural gas)

Aren't those the same thing?

(I would have though illuminating gases would have more likely referred
to man made coal gas etc)


Natural gas as supplied for fuel is about 90% methane CH4, most of the
rest being ethane C2H6 and a little CO2 and N2.

AFAIK the toxicity of Natural gas is quite low; the explosion hazard is
much more significant long before the toxicity is an issue.

[Coal] Miners are exposed to methane at around 0.1-0.9% in air (more than
than that and the electric gets turned off and work stops). Apparently
breathing methane all day at those concentrations might give you a slight
headache.

Manufactured gas, aka town gas, city gas or first family gases are
extremely toxic as they contain substantial quantities of CO.

The OP should not worry about breathing tiny amounts of CH4. HOWEVER any
smell of gas is unacceptable, a large leak smells just the same.



--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards