Flammable gas sensor not going off despite a smell of gas

[Guest Liznic]

I bought a Honeywell EzSense gas detector for flammable gases. It did not detect a gas leak in my cooker which has now been condemned by the gas authorities.

I bought this product because I thought I could smell a very faint smell of gas. It failed to detect a leak and in the end I called out the gas authorities who found a leak in my cooker. I now have a new cooker, but I have wasted my money on the detector. Is it faulty?

Liz

[Safelincs]

Hi Liz

The purpose of such a device is to very early detect potentially dangerous concentrations of flammable gas that could lead to explosions and to pin-point the source of the leak. The explosion limit for natural gas is around 4% (so if 4% of a room would be filled with natural gas, an explosion could occur). The EzSense will detect the presence of the gas already at 0.05%! So there is a 80-fold safety margin!

The reason why you could smell gas while the sensor could not, is the fact that natural gas has an odorant added to help the detection of leaks. http://www.orbital-uk.com/natural-gas-odorant-injection

Your nose will, in broad terms and looking at the overall room, be a better odorant detector than the EzSence is a gas-concentration detector, therefore you would have been alarmed by the smell prior to the sensor setting off. However, the sensor will be able to pinpoint the source of a leak where a human nose would just be overwhelmed by the smell without being able to find the location.