Thread: Strong sulphur smell in TD5 ventilation system

Did somebody say Science?!


An interesting property of H2S is olfactory Fatigue.
It's an annoyance in low concentrations (can be smelt as low as 0.008ppm), and respiratory complaints at much higher concentrations around 10ppm. Deadly at approx 500ppm.

The interesting part is where you lose the ability to smell it as exposure increases with time. The threshold is approx 100ppm.
Here's a case of a poor bugger who copped a solid lung-full after welding inside a tank used to store sulfur products in an oil refinery. Almost died. (I'm hoping to have my 'solid lung-full' accepted by the International System of Units... watch this space!)

This article discusses further the aetiology, and clinical signs of H2S poisoning.
H2S affects Cytochrome C oxidase, a mitochondrial protein that is used in the oxidative phosphorylation process, which converts ADP to ATP- one of the chemical 'fuels' our body uses. Cyanide also affects this same protein.

Don't be alarmed though... the low levels needed to smell H2S are a long way from something that will kill you.
H2S is an interesting gas.

[QUOTE=Toxic_Avenger;2699283]Did somebody say Science?!

Yes

http://ehs.whoi.edu/ehs/occsafety/leadAcidprocedure.pdf

Near the end of para 4 on page 3 we have the smoking (battery) gun
• Over-charging a lead-acid battery can produce hydrogen-sulfide, which is colorless, very poisonous,flammable, and has the odor of rotten eggs.

Check the battery(s)

Thanks for all the replies about this!

Well after the problem seemingly went away over use over weekend it was back this afternoon. Opened the bonnet and the smell very strong around the aux battery. I checked the volts to main and aux battery a bit later on (no smell at that time though) both steady at around 12-14 volts (couldn't get exact as it was dark). Nanocom said ~13.85 to 14.05 volts - which are pretty normal readings.

So what should I do now?

Take out affected battery?

Originally Posted by Toxic_Avenger

Did somebody say Science?!


An interesting property of H2S is olfactory Fatigue.
It's an annoyance in low concentrations (can be smelt as low as 0.008ppm), and respiratory complaints at much higher concentrations around 10ppm. Deadly at approx 500ppm.

The interesting part is where you lose the ability to smell it as exposure increases with time. The threshold is approx 100ppm.
Here's a case of a poor bugger who copped a solid lung-full after welding inside a tank used to store sulfur products in an oil refinery. Almost died. (I'm hoping to have my 'solid lung-full' accepted by the International System of Units... watch this space!)

This article discusses further the aetiology, and clinical signs of H2S poisoning.
H2S affects Cytochrome C oxidase, a mitochondrial protein that is used in the oxidative phosphorylation process, which converts ADP to ATP- one of the chemical 'fuels' our body uses. Cyanide also affects this same protein.

Don't be alarmed though... the low levels needed to smell H2S are a long way from something that will kill you.
H2S is an interesting gas.

Thanks for busting out the science Mitch!

a32.jpg

Originally Posted by akula

Thanks for all the replies about this!

Well after the problem seemingly went away over use over weekend it was back this afternoon. Opened the bonnet and the smell very strong around the aux battery. I checked the volts to main and aux battery a bit later on (no smell at that time though) both steady at around 12-14 volts (couldn't get exact as it was dark). Nanocom said ~13.85 to 14.05 volts - which are pretty normal readings.

So what should I do now?

Take out affected battery?

Process of elimination, I guess. Try it and see. How old is that Battery?

Originally Posted by bob10

Process of elimination, I guess. Try it and see. How old is that Battery?

2+ years old at least, was in it when I bought the car.
I topped it up about 3 weeks ago.

Originally Posted by akula

I topped it up about 3 weeks ago.

Bingo, overfilled maybe?

Originally Posted by discorevy

Bingo, overfilled maybe?

That's quite possible.
But why now and not back when I did this?
And why intermittently?