Gas safety pressure check?

[Morganic]

Another issue raised in my habitation service was the lack of an inspection point to check the gas system for leaks . Anyone know how this is done?
On my caravan the engineer was able to pressurise the system and see if the pressure dropped because of a leak.
Doesn't appear that this can be done on a California!
Another issue I have raised with VW Commercials Vehicles. Call handler seems to think it had been raised before.
I know the California might be the only true VW camper but it doesn't mean it shouldn't be safe for habitation. Mine isn't at present!

 

[Pineweasel]

I had my gas system checked recently by a certified engineer. No problems reported and he certainly didn't mention that the system was lacking anything. All camper vans have a similarly simple setup as far as I know.

 

[Morganic]

I had my gas system checked recently by a certified engineer. No problems reported and he certainly didn't mention that the system was lacking anything. All camper vans have a similarly simple setup as far as I know.

Glad to hear your engineer was able to test yours. I'd like to know how he did it because my guy is having difficulty and has even gone to the suppliers of the regulator for advice. They say he needs to set up a test rig with some piping and told him what is required. He's going to get it sorted.

 

[Tactical]

Glad to hear your engineer was able to test yours. I'd like to know how he did it because my guy is having difficulty

But in your Habitation Service post, you said:

The tester is highly experienced and totally competent and AWS and MCEA approved. He was also a VW apprentice who did his time and has tested all types of VW campers.

I can't help wondering why he is having these problems with a California if he has tested all types of VW campers?

 

[bigmac77]

There is no test point on my Cali, to test you would have to insert one into the line.

 

[Pineweasel]

The testing is done by removing the gas bottle and regulator and pressurizing from there.

 

[CYCLOPATH]

I come from a mining area originally, so my suggestion would be to put a canary in the van for the night, and see if it is alive in the morning.

 

[WelshGas]

Another issue raised in my habitation service was the lack of an inspection point to check the gas system for leaks . Anyone know how this is done?
On my caravan the engineer was able to pressurise the system and see if the pressure dropped because of a leak.
Doesn't appear that this can be done on a California!
Another issue I have raised with VW Commercials Vehicles. Call handler seems to think it had been raised before.
I know the California might be the only true VW camper but it doesn't mean it shouldn't be safe for habitation. Mine isn't at present!

They do not seem to have this problem in Germany. VW have to test to get the TUV certificate, see disc on boot door. Also they have to be retested, I think, every 12 or 24 months in Germany to comply with TUV regulations. So they manage it. Your ex-VW technician seems very knowledgeable.

 

[bigmac77]

The testing is done by removing the gas bottle and regulator and pressurizing from there.

If your doing that then presumably this is just an air test rather than a test using LPG under pressure. This is not enough to test the gas tightness of the setup. It has to be done with LPG under pressure due to molecule size of LPG being smaller than that of air and more able to search out a small leak.

Air tests are carried out at 45mb pressure (LPG working pressure is 37mb) but it is still not enough to check for leaks alone.

 

[WelshGas]

If your doing that then presumably this is just an air test rather than a test using LPG under pressure. This is not enough to test the gas tightness of the setup. It has to be done with LPG under pressure due to molecule size of LPG being smaller than that of air and more able to search out a small leak.

Air tests are carried out at 45mb pressure (LPG working pressure is 37mb) but it is still not enough to check for leaks alone.

I'm not sure where you have got your information from, but:

AIR
Molecular Weight

• Molecular weight : 28.96 g/mol

Solid phase

• Melting point (incipient freezing point) : -214 °C

Critical point

• Critical temperature : -140.6 °C
• Critical pressure : 37.66 bar
• Critical density : 319.93 kg/m3

BUTANE
Molecular Weight

• Molecular weight : 58.122 g/mol

Solid phase

• Melting point : -138.29 °C
• Latent heat of fusion (1,013 bar, at melting point) : 80.193 kJ/kg

Liquid phase

• Liquid density (1.013 bar at boiling point) : 601.26 kg/m3
• Liquid/gas equivalent (1.013 bar and 15 °C (59 °F)) : 236.4 vol/vol
• Boiling point (1.013 bar) : -0.49 °C
• Latent heat of vaporization (1.013 bar at boiling point) : 385.71 kJ/kg

Critical point

• Critical temperature : 151.98 °C
• Critical pressure : 37.96 bar
• Critical density : 228 kg/m3

From this Data you can see that Butane has a higher molecular weight than Air and also a larger molecular structure than Air ( which is in fact made up of a combination of molecules of O2 and N2 in the majority. )

This physical property is the reason why the Gas holder has a VENT at the bottom of the Holder.

Using Air, or a Lighter than Butane gas substitute is more likely to find a leak under pressure than Butane under pressure.

I could be wrong, as it has been a long time since my basic O & A level Chemistry.

 

[bvddobb]

Welshgas, you are absolutely right.

Our Cali is a little older, so we have had to renew our TÜV gas certificate several times now, to get a new sticker etc. We have done that at TÜV Nord, who have a representation in NL. There is also a yellow gas certificate booklet with the car, that is filled in every time with the test results, and is the real certificate of the gas safety. A bit like your car service booklet.

At he test they do all the things describe here and on the forum elsewhere earlier, like does the gas stop when the flame is blown out, the age of the gas tube, the functioning of the pressure regulator, etc. AND they check the system for leaks. With air under pressure, after removing the gas bottle and regulator, just like Bigmac 77 writes.

 

[bigmac77]

I am a Gas Safe Registered engineer qualified on LPG for leisure accommodation vehicles (static caravans, touring caravans and motorhomes). Your chemistry is better than mine but have always been told during training and reassessment that LPG can find leaks that air can't.

Gas tightness test is as follows. For a new installation test at 45mb with air, this is to make sure you don't have a joint not done up or a pipe accidentally left open ended. If you pass this test you then purge air from pipes by lighting all alliances and test with LPG at 30mb. You then do one final test at 5mb, this is to check that the regulator or cylinder valve is not letting gas through when turned off. If you pass all these the installation is deemed gas tight.

 

[snowy55]

You then do one final test at 5mb, this is to check that the regulator or cylinder valve is not letting gas through when turned off. If you pass all these the installation is deemed gas tight.

There doesn't appear to be a test point on the Cali gas system, do you have to have one fitted to carry out these pressure tests?

 

[bigmac77]

Yes but an engineer could install one temporarily to carry out the test.

 

[larrylamb]

Surely an inline pressure meter between the bottle and Cali gas pipe would suffice?

 

[Hotel California]

See this posted just today
http://vwcaliforniaclub.com/threads/gas-safety-check-day-25th-feb-here-at-vwcampersales.12874/

 

[CYCLOPATH]

I'm not sure where you have got your information from, but:

AIR
Molecular Weight

• Molecular weight : 28.96 g/mol

Solid phase

• Melting point (incipient freezing point) : -214 °C

Critical point

• Critical temperature : -140.6 °C
• Critical pressure : 37.66 bar
• Critical density : 319.93 kg/m3

BUTANE
Molecular Weight

• Molecular weight : 58.122 g/mol

Solid phase

• Melting point : -138.29 °C
• Latent heat of fusion (1,013 bar, at melting point) : 80.193 kJ/kg

Liquid phase

• Liquid density (1.013 bar at boiling point) : 601.26 kg/m3
• Liquid/gas equivalent (1.013 bar and 15 °C (59 °F)) : 236.4 vol/vol
• Boiling point (1.013 bar) : -0.49 °C
• Latent heat of vaporization (1.013 bar at boiling point) : 385.71 kJ/kg

Critical point

• Critical temperature : 151.98 °C
• Critical pressure : 37.96 bar
• Critical density : 228 kg/m3

From this Data you can see that Butane has a higher molecular weight than Air and also a larger molecular structure than Air ( which is in fact made up of a combination of molecules of O2 and N2 in the majority. )

This physical property is the reason why the Gas holder has a VENT at the bottom of the Holder.

Using Air, or a Lighter than Butane gas substitute is more likely to find a leak under pressure than Butane under pressure.

I could be wrong, as it has been a long time since my basic O & A level Chemistry.

I love your posts Welshgas, they are always so informative.
I have always been a devotee of looking at problems from the point of view of first principles. So much doctrine is historically based , and so much , especially in our profession, has been shown to be wrong , when properly tested

 

[CYCLOPATH]

I am a Gas Safe Registered engineer qualified on LPG for leisure accommodation vehicles (static caravans, touring caravans and motorhomes). Your chemistry is better than mine but have always been told during training and reassessment that LPG can find leaks that air can't.

Gas tightness test is as follows. For a new installation test at 45mb with air, this is to make sure you don't have a joint not done up or a pipe accidentally left open ended. If you pass this test you then purge air from pipes by lighting all alliances and test with LPG at 30mb. You then do one final test at 5mb, this is to check that the regulator or cylinder valve is not letting gas through when turned off. If you pass all these the installation is deemed gas tight.

Thanks Bigmac, that it's really useful information. Based on the molecule size information from Welsh Gas above, your protocol would make sure that the test is done safely, and no risk of leaking gas, which could be dangerous.
It's great the forum has such a wide spread of skills and knowledge .

 

[larrylamb]

I'm not sure where you have got your information from, but:

AIR
Molecular Weight

• Molecular weight : 28.96 g/mol

Solid phase

• Melting point (incipient freezing point) : -214 °C

Critical point

• Critical temperature : -140.6 °C
• Critical pressure : 37.66 bar
• Critical density : 319.93 kg/m3

BUTANE
Molecular Weight

• Molecular weight : 58.122 g/mol

Solid phase

• Melting point : -138.29 °C
• Latent heat of fusion (1,013 bar, at melting point) : 80.193 kJ/kg

Liquid phase

• Liquid density (1.013 bar at boiling point) : 601.26 kg/m3
• Liquid/gas equivalent (1.013 bar and 15 °C (59 °F)) : 236.4 vol/vol
• Boiling point (1.013 bar) : -0.49 °C
• Latent heat of vaporization (1.013 bar at boiling point) : 385.71 kJ/kg

Critical point

• Critical temperature : 151.98 °C
• Critical pressure : 37.96 bar
• Critical density : 228 kg/m3

From this Data you can see that Butane has a higher molecular weight than Air and also a larger molecular structure than Air ( which is in fact made up of a combination of molecules of O2 and N2 in the majority. )

This physical property is the reason why the Gas holder has a VENT at the bottom of the Holder.

Using Air, or a Lighter than Butane gas substitute is more likely to find a leak under pressure than Butane under pressure.

I could be wrong, as it has been a long time since my basic O & A level Chemistry.

Does this mean that this gas detector is bull****
http://www.southdownsmotorcaravans.co.uk/accessories/cbe_narcotic_gas_supplies.php

 

[WelshGas]

Does this mean that this gas detector is bull****
http://www.southdownsmotorcaravans.co.uk/accessories/cbe_narcotic_gas_supplies.php

Correct. After 41 years in Anaesthetics the cheapest Narcotic Gas Analyser costs about £3.5k in standalone form. That monitor is useless.
For more info http://www.rcoa.ac.uk/news-and-bull...ents/statement-alleged-gassing-motor-vehicles

 

[larrylamb]

Thanks WG. Not good from a reputable dealer.

 

[WelshGas]

Thanks WG. Not good from a reputable dealer.

Just playing on uninformed fears.

 

[bigmac77]

Does this mean that this gas detector is bull****
http://www.southdownsmotorcaravans.co.uk/accessories/cbe_narcotic_gas_supplies.php

It does state that it is an LPG detector but LPG is heavier than air so any leak is going to result in the gas falling to the floor. If you put that detector under a known leak it may go off otherwise I wouldn't bother.

As an aside that is why there is a hole in the bottom of the gas bottle enclosure, if there is a leak the gas will just fall out of the van.

 

[larrylamb]

It does state that it is an LPG detector but LPG is heavier than air so any leak is going to result in the gas falling to the floor. If you put that detector under a known leak it may go off otherwise I wouldn't bother.

As an aside that is why there is a hole in the bottom of the gas bottle enclosure, if there is a leak the gas will just fall out of the van.

Yes I agree but they are contradicting themselves by saying it is intended for LPG but will detect narcotic gases and should be mounted higher.


"This device has been specifically designed for the protection against LPG. An audible alarm informs about the presence of soporific gas in the air before it affects people inside your motorhome.

The sensor signals (by means of very loud noise) the presence of soporific gas inside your wagon.

The soporific gas (which is often used by burglars, apparently) is lighter than air and will therefore concentrate at the top of the compartment; we therefore usually position the detector at eye-height, in the sleeping area of the compartment."

 

[WelshGas]

Yes I agree but they are contradicting themselves by saying it is intended for LPG but will detect narcotic gases and should be mounted higher.


"This device has been specifically designed for the protection against LPG. An audible alarm informs about the presence of soporific gas in the air before it affects people inside your motorhome.

The sensor signals (by means of very loud noise) the presence of soporific gas inside your wagon.

The soporific gas (which is often used by burglars, apparently) is lighter than air and will therefore concentrate at the top of the compartment; we therefore usually position the detector at eye-height, in the sleeping area of the compartment."

There is no known clinically effective narcotic gas which is lighter than air. FACT.