Gas Bullsh**

[Timleech]

lp gas eats into the orange rubber hose material and makes it brittle

 

Orange hoses used to be the norm, lined with black neoprene AFAIAA.

 

So - is the elevated pressure test for a new installation a thing of the past?

I used to have a special longer manometer to do it. Purely academic interest, I haven't touched gas since compulsory CORGI registration for installers came in.

 

Tim

[dor]

Just out of interest Biggles, looking at your gas locker, do you expect that installation to pass a proper BSS examination?

[smileypete]

lp gas eats into the orange rubber hose material and makes it brittle

OK... another question if you don't mind:

 

I did indeed drop the pressure down from 37mb not as much as you are suggesting but to 35mb and yes of course the bottle supply tap was turned off indeed my regulator assy. has a tap on it for this very purpose imediatly before the test point.

If the tap is after the regulator and Biggles turned it off when doing the pressure drop test, does this mean the test method is sound?

 

Edit:

 

Just out of interest Biggles, looking at your gas locker, do you expect that installation to pass a proper BSS examination?

What do you think is wrong with it, apart from no lid that I can see, and possibly no restraint to stop the single bottle falling over?

 

Edit 2

 

Does he actually test LPG installations, or is his manometer used for natural gas?

 

or is that just another minor detail that you aren't going to bother with?

Think it would be OK used on LPG, just the once

 

cheers,

Pete.

Edited May 14, 2012 by smileypete

[Chris Pink]

Once again mayalld you miss the point completely in your eagerness to argue. The BSS test is for the examiner to know your gas system is safe. I am certainly not relying AT ALL on a 4 yearly test to keep myself safe. I do that be my vigilance and safe practice.

 

It is not difficult with careful and thorough work to make an LPG system, after all plumbers do it. Sloppy work and ignorance cause LPG incidents.

 

The examiner comes along and doesn't inspect every joint or live-in the boat for a day and smell for gas. He doesn't check the bottles are gas tight when changed

 

I didn't know about the details of the test that you and hamsterfan giggled over like schoolboys but I knew my system would pass.

 

OK... another question if you don't mind:

 

 

If the tap is after the regulator and Biggles turned it off when doing the pressure drop test, does this mean the test method is sound?

 

cheers,

Pete.

 

Another question in an attempt to learn.

 

The test point is supposed to be at the farthest practical point in the system but if the pressure is equal throughout does a pressure test at the regulator show the same leak tightness?

Edited May 14, 2012 by Chris Pink

[Guest]

So, the basic upshot is that despite the fact that you don't have sufficient knowledge to KNOW whether something is safe, your hunch that it will probably be OK is sufficient?

 

If you were the only person who was going to die when it goes wrong, it wouldn't be such a big problem.

 

 

 

 

OK, I sense that others are actually tempted to hand you a larger shovel to dig yourself an even deeper hole here, and as I asked you the trick question, I will actually explain it to you.

 

You start the test by pressurising the system from the bottle, and seeing that the manometer indicates 37mb (showing that the regulator is doing its job).

 

Then you turn the bottle off (please tell me that you at least did this bit). The manometer still shows 37mb.

 

Now, assume that you have a small leak. What will the manometer show 5 minutes later? The answer is that it will STILL show 37mb.

 

The reason that testing at 37mb won't work is that at 37mb you have still got a small amount of HP gas on the hp side of the regulator, and the regulator will let that gas into the LP side to compensate for any leaks until the HP side is also at 37mb. This means that a small leak will not be apparent.

 

The CORRECT way to test for leaks is at 25-30mb, as follows;

 

Turn the bottle off, light the smallest burner on the cooker and watch as the manometer stays at 37mb for a while. As soon as it starts to drop, turn the burner off. You should now be somewhere in the high 20's, and should stay there.

 

At this point, you know that you are testing the soundness of the LP pipework, rather than simply seeing the leaking gas replaced from the HP side.

 

Testing a gas system for leaks at 37mb proves only that you shouldn't be testing gas systems.

 

 

 

If your gas system was subjected to a soundness test with a manometer at 37mb, I would suggest that you report him to the BSS office immediately, because he has carried out a test that simply will not prove the soundness of the system, and he shouldn't be testing gas systems.

Have to agree, my inspector ALWAYS does this reduced pressure test that you describe. He has done 3 inspections for me to date and I trust him 100%

[the grinch]

Orange hoses used to be the norm, lined with black neoprene AFAIAA.

 

 

Tim

and that is the point! a test hose is single ply unlined no neoprene content.

 

OK... another question if you don't mind:

 

 

cheers,

Pete.

what was the question?

 

 

If the tap is after the regulator and Biggles turned it off when doing the pressure drop test, does this mean the test method is sound?

 

cheers,

Pete.

No. as he has not tested from the regulator to the isolation valve (Unless he has tested at High Pressure the pigtails, regulator and associated changeover valve with it off in which case the test would prove the connection)

 

The manometer was loaned to me by a gas safe regestered engineere who I know has been in the industry 40+ years so I'll trust his equipment over your assumption that it's orange it can't be neoprene.

 

 

 

If he was an LPG Boats qualified engineer he should know the type of hose required to test LPG. I make no assumption, as i have NEVER seen an orange neoprene hose it doesn't mean that one doesn't exist feel free to show me one!.

 

 

It's clear your are not going to be convinced I am competent, and as I said before I don't really care as you are nothing to me. I am really disappointed in myself for letting myself be drawn it this debate so deeply with you. Had ii not been raining cats and dogs I would have much better things to do today.

 

Hopefully this debate will deter others with even less competence that are reading it from having a go at gas as despite your thoughts on me you do make valid points.

 

I shall now retire from this side debate on my competence. But please knock yourselves out boys by continuing to berate me. I know I have made a safe and beautiful boat with my otherwise incompetent hands.

 

1. its not really a debate, just trying to tell you before you get a fail on your examination where things are wrong.

2. hopefully this will encourage others to do things in the right way with the right materials.

3. take your ball and go home if you wish that is your decision or stay and those of us suitably qualified will try to help you avoid the pitfalls of DIYing your install and having it ripped to pieces by the tester.

 

as for the gas locker I can't advise you on the suitability other than i would personally prefer the changeover valve to be protected more from bumps and bashes whilst changing bottles as the valve head will get damaged very quickly if you are not extremely careful.

 

kev

[the grinch]

It is not difficult with careful and thorough work to make an LPG system, after all plumbers do it. Sloppy work and ignorance cause LPG incidents.

 

The examiner comes along and doesn't inspect every joint He doesn't check the bottles are gas tight when changed

 

I didn't know about the details of the test that you and hamsterfan giggled over like schoolboys but I knew my system would pass.

 

The test point is supposed to be at the farthest practical point in the system but if the pressure is equal throughout does a pressure test at the regulator show the same leak tightness?

 

careful and thorough - exactly use of correct materials and test is part of that. sloppy work can be done by registered as well!

where did I giggle I mearly pointed out that testing at 37Mbar is incorrect

 

the test point should ideally be at the furthest point but it is not mandatory as far as I know, a bubble tester is again a good idea but not mandatory.

and yes a leak would be uniform no matter where in the section the test point is fitted.

[MtB]

A couple of further points:

 

When I first did my LPG on boats ticket a new installation was initially tested at 70mB using air. Zero mBar drop in a five minute test. If it passes, then progress to charging the system with LPG then do a let-by rest at 10 mBar (no pressure rise) followed by a soundness test at 30 mBar for five minutes. No pressure drop.

 

I last got into a squabble with Biggles about this a year or so ago on here where he said this was stupid and he tested at 2 BAR overnight. (Yes 2.0 BAR!) And no pressure drop in the morning would be fine. At this point I gave up trying to advise.

[Timleech]

A couple of further points:

 

When I first did my LPG on boats ticket a new installation was initially tested at 70mB using air. Zero mBar drop in a five minute test. If it passes, then progress to charging the system with LPG then do a let-by rest at 10 mBar (no pressure rise) followed by a soundness test at 30 mBar for five minutes. No pressure drop.

 

 

 

So - what is the answer to my question, is the initial high pressure test no longer deemed to be necessary?

 

Tim

[RLWP]

So - what is the answer to my question, is the initial high pressure test no longer deemed to be necessary?

 

Tim

 

I wonder if we are hearing different experiences for new and old boats. I've never seen the high pressure test, but ours is an old boat

 

Richard

[the grinch]

the tests have changed I'm out at the moment but can look up the change date when I get back home

[MtB]

So - what is the answer to my question, is the initial high pressure test no longer deemed to be necessary?

 

Tim

 

As I understand it the initial high pressure test (with appliances isolated) is deemed necessary for new installations, prior to being charged with LPG for the first time. If you consider 45mBar to be 'high pressure'.

 

New installations are tested differently from 'existing installations' in that a soundness test at 45mBar using air as the test gas is necessary first. This is according to Appendix C in PD 5482-2005 part III.

 

So to answer your question, the intital high pressure test is deemed necessary for new systems but not for systems already in use.

 

Mike

 

(Edited to improve clarity.)

Edited May 14, 2012 by Mike the Boilerman

[gazza]

A couple of further points:

 

When I first did my LPG on boats ticket a new installation was initially tested at 70mB using air. Zero mBar drop in a five minute test. If it passes, then progress to charging the system with LPG then do a let-by rest at 10 mBar (no pressure rise) followed by a soundness test at 30 mBar for five minutes. No pressure drop.

 

I last got into a squabble with Biggles about this a year or so ago on here where he said this was stupid and he tested at 2 BAR overnight. (Yes 2.0 BAR!) And no pressure drop in the morning would be fine. At this point I gave up trying to advise.

 

this is the correct procedure for gas testing.

 

the reason you should test at 30 mB is to allow the gauge to stabilise from regulator lock up at 37mB. dropping to 30 mB gives an accurate reading to check for pressurre drop within the system.

[Timleech]

As I understand it the initial high pressure test (with appliances isolated) is deemed necessary for new installations, prior to being charged with LPG for the first time. If you consider 45mBar to be 'high pressure'.

 

New installations are tested differently from 'existing installations' in that a soundness test at 45mBar using air as the test gas is necessary first. This is according to Appendix C in PD 5482-2005 part III.

 

So to answer your question, the intital high pressure test is deemed necessary for new systems but not for systems already in use.

 

Mike

 

(Edited to improve clarity.)

 

OK, so there has not been a fundamental change.

 

Thanks

 

Tim

[the grinch]

as promised the first test is 111mbar (3x37mbar) air test (on new carcasses only)Ref.TM62 A3

 

High pressure (pigtails) test at maximum (usually around 5bar from my experience) 5mins stabilisation , 5 minute test. Ref. BS5482

let by test pressure to lock up, close valve, bring down to 5 mbar, release back pressure from UPSO 5 min stabilise 2 min test no discernable rise (0.25mbar)(ref. TM62 B1.1

tightness (was soundness)testpressure to max (37 or 28mbar) 5 min stabilise, lower pressure to 30mbar 2 min test Ref. TM62 B2

Edited May 14, 2012 by hamsterfan

[ditchcrawler]

as promised the first test is 111mbar (3x37mbar) air test (on new carcasses only)Ref.TM62 A3

 

High pressure (pigtails) test at maximum (usually around 5bar from my experience) 5mins stabilisation , 5 minute test. Ref. BS5482

let by test pressure to lock up, close valve, bring down to 5 mbar, release back pressure from UPSO 5 min stabilise 2 min test no discernable rise (0.25mbar)(ref. TM62 B1.1

tightness (was soundness)testpressure to max (37 or 28mbar) 5 min stabilise, lower pressure to 30mbar 2 min test Ref. TM62 B2

Well I am glad that Mike to boiler is here and that you posted the above.

I am not a gas safe fitter or Corgi but I spent the best part of 30 years working in the natural gas industry with pressurs up to 3000 psi and I would never pressure test a new installation with a flammable product. If it does fail you could have lots of problems on your hands and untill you test it you don't know it's sound. As for pressure I have always tested to test pressure which is above working working pressure. Also temperature comes into it as temperature changes will also give pressure changes.

 

Now a question. With a closed gas system on a boat, if no gas is being used and the temperature rises in the boat by say 20deg C will the pressure in the gas lines rise or can it be relieved by the regulator?

[the grinch]

i would expect a small rise in pressure if the pipes were directly or indirectly (say through a window) heated by say the sun. the carcass should take that without to much difficulty and that is as I understand it why the air test is 3 x operating pressure.

[the grinch]

going back to my previous post I can't find the date the test methods changed (or more importantly the exam changed!!) but I had to do the high pressure test on the last but 1 exam in 2005 but didn't when i retook in 2010 so its somewhere in that period presumably as a result of PD5482 pt 1-3 revision in 2005.

 

Well I am glad that Mike to boiler is here and that you posted the above.

I am not a gas safe fitter or Corgi but I spent the best part of 30 years working in the natural gas industry with pressurs up to 3000 psi and I would never pressure test a new installation with a flammable product.

 

absolutely!! i think the problem here is that having ballsed up the OP is kicking himself and feels that those of us that are in the industry are out to get him, nothing could be further from the truth and if he was only to listen and learn then we would help to the best of our ability. I have been a gas engineer since the 90's having first learnt the ropes (sometimes the hard way!!) from others during my time at FBS and Clubline (got my aris kicked for leaving a gas leak on a job at clubline due to my inexperience and being taught what i should have done)

 

no one should be put off doing their own work, but they do need to make sure they are doing so safely.

[ditchcrawler]

going back to my previous post I can't find the date the test methods changed (or more importantly the exam changed!!) but I had to do the high pressure test on the last but 1 exam in 2005 but didn't when i retook in 2010 so its somewhere in that period presumably as a result of PD5482 pt 1-3 revision in 2005.

 

 

 

absolutely!! i think the problem here is that having ballsed up the OP is kicking himself and feels that those of us that are in the industry are out to get him, nothing could be further from the truth and if he was only to listen and learn then we would help to the best of our ability. I have been a gas engineer since the 90's having first learnt the ropes (sometimes the hard way!!) from others during my time at FBS and Clubline (got my aris kicked for leaving a gas leak on a job at clubline due to my inexperience and being taught what i should have done)

 

no one should be put off doing their own work, but they do need to make sure they are doing so safely.

I wasn't having a go at the OP or anyone else but questioning the professionals on here who advocate pressure test with product only to working pressure.

[Biggles]

I'm not kicking myself. It's only time and money. The former is anyones guess even if I have done my own gas install. The latter I really have no worries. In fact when I was told the gas install had to come out I was perversely pleased as I had another job to do on the boat.

[the grinch]

you are weird i wouldn't want to have to do things twice (although Wey and Arun tradition is that we do things 3 times before we get it right!)

[alan_fincher]

you are weird i wouldn't want to have to do things twice (although Wey and Arun tradition is that we do things 3 times before we get it right!)

Sounds like BW's attempts to erect the "safety" hand rails at those Staffs and Worcs lock tail bridges.....

[the grinch]

loxwood high street tunnel!! 2nd attempt at railings!

[Radiomariner]

I think some of you are being a bit unfair on Biggles. At least he has carried out a tightness test the results of which he is happy with. He intends to get a BSS exams shortly. Many DIY'ers do little more than sniff around for the smell of gas! His test shows that at least there is not a gigantic leak.

The BSS presently encourages owners to test for gas leaks using bubble testers, they do not recommend DIY manometer tests. Therefore, in their guide book, there are no details of the test for Biggles to follow.

After posting this I will be looking up the exact wording of the full BSS test procedure as so many posters have got bits of it wrong. It is quite long and may take a while for me to type up, so it will be in a seperate post.

About Biggles Gas locker, I want to mention the absence of a 2nd gas bottle. I see that the pigtails are fitted with non return valves thus preventing high pressure leakage out through the block and the unconnected pigtail. So there is no failure point. However The change over valve can not always be relied upon to completelly shut off the flow to the unused pigtail and NRV's rely on pressure to keep closed, a small leak past the valve may not create enough pressure to hold the NRV shut. OK it is a small leak and within the safety of the gas locker but over time you may loose a significant quantity of gas.

Now I am off to look up the Examiners test procedure.

Edited May 15, 2012 by Radiomariner

[RLWP]

<snip>

 

I want to mention the absence of a 2nd gas bottle. I see that the pigtails are fitted with non return valves thus preventing high pressure leakage out through the block and the unconnected pigtail. So there is no failure point. However The change over valve can not always be relied upon to completelly shut off the flow to the unused pigtail and NRV's rely on pressure to keep closed, a small leak past the valve may not create enough pressure to hold the NRV shut

 

<snip>

 

That was well worth posting. We often have only one bottle connected and one pigtail left dangling. I won't do that in future

 

Thank you

 

Richard