Safe way of testing for hydrogen?

[allthebuttons]

I have a radiator which regularly needs bleeding and I’d like to check whether the gas coming out is hydrogen.

Is there a safe way of doing this (i.e. that doesn’t involve setting fire to it)?

 

[Madrab]

Nothing really that doesn't involve a chemistry lab and lots of different chemicals.

 

[mikeey84]

The way we used to test when I studied chemistry is thus:
Using a test tube, or similar slim tube, closed at one end, with a diameter of approx 1cm, position it vertically with the opening as close to the gas release as possible.

If it's hydrogen, it's lighter than air, so the idea is to catch it in the bottom of the tube.

Once you have done this, insert a lot, long match into the tube.

If it's hydrogen, there will be a slight pop, and flash. If it isn't hydrogen, the match will just continue to burn as usual, or go out.

 

[bernardgreen]

Be aware that the gas coming out of a radiator may be a mixture of hydrogen and oxygen and could be in the correct ratio to be explosive. This mixture can flash back through very small holes such as a bleed nipple and ignite ( explosively ) the gas mixure inside a radiator.

Very unlikely but not worth the risk of testing with a flame next to the bleed nipple.

 

[mikeey84]

Fair point from Bernard.

Remove yourself from the area before you light the match!

 

[allthebuttons]

Thanks for the answers - I’m aware of the basic physics of lighting the hydrogen, but I was hoping for a safer alternative. I watched a YouTube video of someone attempting to safely ‘pop’ the hydrogen in an upturned kettle, but accidentally setting fire to their radiator!

 

[Jackrae]

If it's from decomposition of living matter it'll more likely be hydrogen sulphide (rotten egg smell) or methane

 

[allthebuttons]

If it's from decomposition of living matter it'll more likely be hydrogen sulphide (rotten egg smell) or methane

Definitely no smell. Just trying to establish if it’s corrosion or a leak.

 

[Celeronmanuk]

I did this myself with a small shot glass, certainly made me jump, a bit more than a pop! Took a flush with cleaner and new inhibitor to stop the hydrogen. It was a brand new system which was meant to have been flushed clean already!