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One of the LPG systems on my boat seems to have developed a leak. (I have two independent systems, one down each side of the boat)

 

I've isolated the oven and hob and the leak persists so it must be upstream of the isolators. I tested the T fitting with leak detector spray. I've also sprayed the upstream side of both isolators. The only other joint in the system is on the gas locker bulkhead. I wanted no joint there and tried to get the half inch pipe though in one go all the way to the appliances when I originally installed the system 15 years ago, but the angle from the pipe on the inside of the locker made that impossible.

 

I've sprayed that fitting on the outside of the locker but haven't managed to get inside the locker yet to spray the fitting from the inside. If it's not leaking then what else could it be? I have sprayed both sides of the bubble tester itself and found nothing.

 

 

IMG_20210409_094811.jpg

Edited by blackrose
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Are both sides supplied from the same cylinder,? If so where is the 'split' (to go down Port and Starboard) ?

 

If both are supplied from one cylinder how do you know that only one side is affected ?

 

Is there any possibility that it is the pipe/hose/regulator to cylinder ?

POL thread - a single grain of 'muck' can produce a leak, a slightly damaged screw thread can cause a leak.

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Just now, Tracy D'arth said:

Reg on the bottle? Checked the rubber hose? Gas isolation taps need re greasing?

How do you know you have a leak? Bubble tester or manometer?

Any smell anywhere?

 

Bubble tester. 

 

But I thought the bubble tester only detected leaks downstream of itself - or at least downstream of the regulator on the low pressure side of the system? 

 

Possibly a feint whiff of gas inside the locker. The bottle is running out so I do get a smell inside the boat if I light the hob which is confusing the issue. No smell if I don't use the gas.

 

 

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Where are you detecting the leak, and how? Manometer at a test point? At the bubble tester?  If so it must be downstream of the test point or BT.  

 

Does the pipe pass through any fixed items where it might vibrate and  chafe. Fixed furniture or pipe clips for example.

 Have you leak tested the isolator operating parts?  They may be leaking round the plug or ball.

 

Can you raise the pressure in the pipe by pumping into a test point for example? Leak fluid is not very sensitive so if you can get the pressure up a bit you can find the leaks more readily.  You still need to do a proper soundness test after fixing any leaks found this way.

N

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23 minutes ago, Alan de Enfield said:

 

Are both sides supplied from the same cylinder,? If so where is the 'split' (to go down Port and Starboard) ?

 

If both are supplied from one cylinder how do you know that only one side is affected ?

 

Is there any possibility that it is the pipe/hose/regulator to cylinder ?

POL thread - a single grain of 'muck' can produce a leak, a slightly damaged screw thread can cause a leak.

 

No they're completely independent systems. The other side has its own bottles, changeover switch, regulator, bubble tester, etc.

 

I don't understand how a bubble tester could be detecting a leak on the high pressure side of the system? That's not possible is it? They only detect downstream of themselves surely? 

Edited by blackrose
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3 minutes ago, BEngo said:

Where are you detecting the leak, and how? Manometer at a test point? At the bubble tester?  If so it must be downstream of the test point or BT.  Yes

 

Does the pipe pass through any fixed items where it might vibrate and  chafe. Fixed furniture or pipe clips for example. All my pipe clips have a bit of plastic electrical conduit inside.

 Have you leak tested the isolator operating parts?  They may be leaking round the plug or ball. But if I'm not getting a leak on the bubble tester with the isolators closed then they must be isolating correctly right?

 

Can you raise the pressure in the pipe by pumping into a test point for example? No I don't have the ability to do that. Leak fluid is not very sensitive so if you can get the pressure up a bit you can find the leaks more readily.  You still need to do a proper soundness test after fixing any leaks found this way.

N

 

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Bubble testers are pretty sensitive, leak detection spray less so. Maybe you need to "try harder" with the leak detecting spray? Or use something more frothy like shaving foam, diluted washing up liquid etc.

You could determine that the isolating valves are actually isolating properly by closing them, operating the hob and overn to depressurise, turning off both those appliances and waiting say overnight, then see if there is a hint of residual pressure after the isolators to the oven / hob, using a match(!). Once you are certain that the isolators are not letting by, you can be sure the problem is upstream of them.

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6 minutes ago, nicknorman said:

Bubble testers are pretty sensitive, leak detection spray less so. Maybe you need to "try harder" with the leak detecting spray? Or use something more frothy like shaving foam, diluted washing up liquid etc.

You could determine that the isolating valves are actually isolating properly by closing them, operating the hob and overn to depressurise, turning off both those appliances and waiting say overnight, then see if there is a hint of residual pressure after the isolators to the oven / hob, using a match(!). Once you are certain that the isolators are not letting by, you can be sure the problem is upstream of them.

 

Ok that sounds like a plan thanks. Trouble is, I'm reluctant to leave the system connected to the bottle overnight, now I know there's a leak.

 

I thought we always told people not to use washing up liquid, or at least to make sure it was thoroughly washed away afterwards because it's corrosive. Now it turns out that it's better than proper gas leak detector spray? I give up!?

 

I don't think it can be pipe chafing.

 

 

IMG_20210409_103530.jpg

Edited by blackrose
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I find using leak spray I have to dabble around the joint with a small paint brush to disperse bubbles that the spray caused and spend time at each joint watching very closely perhaps with a torch while dabbling with the brush, if you wear specs wear them.

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19 minutes ago, blackrose said:

I thought we always told people not to use washing up liquid, or at least to make sure it was thoroughly washed away afterwards because it's corrosive. Now it turns out that it's better than proper gas leak detector spray? I give up

 

The LPG industry does warn against using washing up liquid as the ammonia attacks copper/brass and weakens it.

 

 

Firstly DO NOT use Washing Up Liquid or non approved leak detection sprays as these will damage the brass and stainless steel parts used in gas systems.

It is really important that you use the correct approved leak detection fluid and DO NOT use soapy water or non approved leak sprays as these will lead to significant damage and even failure of the brass or stainless steel components being tested.

In the washing up liquid the Ammonia they put in for example will lead to stress cracks appearing which will seep into all parts of the valve and lead to brass parts failing catastrophically and simply put valves will leak in some way or form. Chlorine in the washing up liquid will cause the same damage to stainless steel parts.

Don't assume all leak detection fluids are the same as it is known in the industry that some leak fluids have significance ammonia and chlorine in them which has caused brass parts to completely crack and shatter even before LPG under pressure was put in the gas system.

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8 minutes ago, Alan de Enfield said:

 

The LPG industry does warn against using washing up liquid as the ammonia attacks copper/brass and weakens it.

 

 

Firstly DO NOT use Washing Up Liquid or non approved leak detection sprays as these will damage the brass and stainless steel parts used in gas systems.

It is really important that you use the correct approved leak detection fluid and DO NOT use soapy water or non approved leak sprays as these will lead to significant damage and even failure of the brass or stainless steel components being tested.

In the washing up liquid the Ammonia they put in for example will lead to stress cracks appearing which will seep into all parts of the valve and lead to brass parts failing catastrophically and simply put valves will leak in some way or form. Chlorine in the washing up liquid will cause the same damage to stainless steel parts.

Don't assume all leak detection fluids are the same as it is known in the industry that some leak fluids have significance ammonia and chlorine in them which has caused brass parts to completely crack and shatter even before LPG under pressure was put in the gas system.

In theory yes, it probably could happen with repeated exposure. In practice, no. Especially if you rinse it off afterwards. 

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14 minutes ago, robtheplod said:

Sorry to hop on here, but do people tend to have a bubble tester plumbed in constantly?  Just seeing if I'm missing a safety device.....

 

Yes, it is a standard part of the permanent gas system.

 

The idea being that you can have a DIY test that you can do as part of your daily checks.

 

If you are a liveaboard then the BSS examiner cannot do the BSS gas tests unless he is also a gas safe registered gas-man.

 

 

Edit to add extract from the BSS

 

 

Carrying out 'work on the gas system of boats used primarily for residential or domestic purposes fall within scope of a piece of UK legislation known as the Gas Safety [Installation and Use] Regulations (GSIUR).

As such, the law demands that anyone contracted to 'work' on the LPG system of a boat in scope must be (LPG boats-competent) Gas Safe registered.

As the definition of 'work' covers the removal and replacement of a screw nipple on a gas test point, the scope of the GSIUR includes carrying out BSS LPG tightness test.

Therefore, on a boat in scope of GSIUR, examiners who are not Gas Safe registered can only complete check 7.12.2 (confirming gas tightness) by either:

  • undertaking a gas tightness test using a bubble leak detector where fitted and correctly located; or,
  • observing the tightness test conducted by a (LPG boats-competent) Gas Safe registered installer

Where a BSS Examiner is also Gas Safe registered is undertaking a BSS Examination of a boat in scope of GSIUR such as if it is a boat used mainly for domestic/residential purposes, the Examiner could potentially identify safety-related LPG issues beyond the extent of the BSS Requirements. In doing so, they may feel duty-bound under their Gas Safe registration to report and discuss the additional issues.

Does a bubble leak detector do away with the need for a Gas Safe registered engineer testing the gas system on residential boats?

Yes, because any BSS Examiner can check for leaks using a fully functioning and appropriately located bubble tester. 

It is the case however that there is no BSS requirement for a bubble leak detector and so fitting one is matter of boat owner choice.

Note that all other types of gas work, such as adding or replacing an appliance, needs to be conducted by a Gas Safe registered engineer with the LPG boat competence listed on his/her identity card.

Is it recommended that boat owners fit a bubble leak detector?

Yes, fitting a bubble leak detector in the LPG cylinder locker is strongly recommended because it allows owners to check for leaks themselves and so enjoy piece of mind in between BSS Examinations. It is very important that fitting bubble leak detector on residential boats (and private leisure boats) is done by a LPG boat-competent Gas Safe registered engineer.

This is because the bubble leak detector must be correctly located and oriented, and for large volume LPG systems, the engineer may need to install a bypass arrangement to allow gas to flow past the detector when it is not being used.

Are there any other alternatives to allow non Gas Safe registered BSS Examiners to check residential boat gas systems?

Unfortunately there are only two methods that can be used to check for gas leaks on boats (manometer leak check and bubble leak detector check). The only other alternative is for the non-Gas Safe registered BSS Examiner to observe a manometer leak check conducted by a LPG boat-competent Gas Safe registered engineer.

Note on the BSS Examination for non-private boats - If a vessel is a hire boat, third-party managed share-owned boat, trip boat, rented residential boat, floating business or some other form of commercial or public vessel, the boat will be examined to either the 2017 Hire Boat Requirements or 2002 BSS Standards as stipulated by the navigation authority registering your boat.

Edited by Alan de Enfield
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9 minutes ago, Alan de Enfield said:

 

Yes, it is a standard part of the permanent gas system.

 

The idea being that you can have a DIY test that you can do as part of your daily checks.

 

If you are a liveaboard then the BSS examiner cannot do the BSS gas tests unless he is also a gas safe registered gas-man.

 

 

Edit to add extract from the BSS

 

 

Carrying out 'work on the gas system of boats used primarily for residential or domestic purposes fall within scope of a piece of UK legislation known as the Gas Safety [Installation and Use] Regulations (GSIUR).

As such, the law demands that anyone contracted to 'work' on the LPG system of a boat in scope must be (LPG boats-competent) Gas Safe registered.

As the definition of 'work' covers the removal and replacement of a screw nipple on a gas test point, the scope of the GSIUR includes carrying out BSS LPG tightness test.

Therefore, on a boat in scope of GSIUR, examiners who are not Gas Safe registered can only complete check 7.12.2 (confirming gas tightness) by either:

  • undertaking a gas tightness test using a bubble leak detector where fitted and correctly located; or,
  • observing the tightness test conducted by a (LPG boats-competent) Gas Safe registered installer

Where a BSS Examiner is also Gas Safe registered is undertaking a BSS Examination of a boat in scope of GSIUR such as if it is a boat used mainly for domestic/residential purposes, the Examiner could potentially identify safety-related LPG issues beyond the extent of the BSS Requirements. In doing so, they may feel duty-bound under their Gas Safe registration to report and discuss the additional issues.

Does a bubble leak detector do away with the need for a Gas Safe registered engineer testing the gas system on residential boats?

Yes, because any BSS Examiner can check for leaks using a fully functioning and appropriately located bubble tester. 

It is the case however that there is no BSS requirement for a bubble leak detector and so fitting one is matter of boat owner choice.

Note that all other types of gas work, such as adding or replacing an appliance, needs to be conducted by a Gas Safe registered engineer with the LPG boat competence listed on his/her identity card.

Is it recommended that boat owners fit a bubble leak detector?

Yes, fitting a bubble leak detector in the LPG cylinder locker is strongly recommended because it allows owners to check for leaks themselves and so enjoy piece of mind in between BSS Examinations. It is very important that fitting bubble leak detector on residential boats (and private leisure boats) is done by a LPG boat-competent Gas Safe registered engineer.

This is because the bubble leak detector must be correctly located and oriented, and for large volume LPG systems, the engineer may need to install a bypass arrangement to allow gas to flow past the detector when it is not being used.

Are there any other alternatives to allow non Gas Safe registered BSS Examiners to check residential boat gas systems?

Unfortunately there are only two methods that can be used to check for gas leaks on boats (manometer leak check and bubble leak detector check). The only other alternative is for the non-Gas Safe registered BSS Examiner to observe a manometer leak check conducted by a LPG boat-competent Gas Safe registered engineer.

Note on the BSS Examination for non-private boats - If a vessel is a hire boat, third-party managed share-owned boat, trip boat, rented residential boat, floating business or some other form of commercial or public vessel, the boat will be examined to either the 2017 Hire Boat Requirements or 2002 BSS Standards as stipulated by the navigation authority registering your boat.

Thanks Alan, looks like its a really good idea for me to get this. How do I determine if i need an 8mm or 10mm one (looking at Midland Chandlers) ?

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Just now, robtheplod said:

Thanks Alan, looks like its a really good idea for me to get this. How do I determine if i need an 8mm or 10mm one (looking at Midland Chandlers) ?

 

What's the diameter of the copper pipe on your gas locker?

 

If it's imperial which is likely, then you need to put the bubble tester in a vice and crack off the fittings and fit the correct size for your pipe.

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3 minutes ago, robtheplod said:

Thanks Alan, looks like its a really good idea for me to get this. How do I determine if i need an 8mm or 10mm one (looking at Midland Chandlers) ?

 

Just use the same size as your gas pipe if that is an imperial size (eg 3/8") then you may need an adapter.

 

Note this from the BSS :

 

Your choice, but this is what they say 

 

 

It is very important that fitting bubble leak detector on residential boats (and private leisure boats) is done by a LPG boat-competent Gas Safe registered engineer.

This is because the bubble leak detector must be correctly located and oriented, and for large volume LPG systems, the engineer may need to install a bypass arrangement to allow gas to flow past the detector when it is not being used.

Edited by Alan de Enfield
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26 minutes ago, Alan de Enfield said:

 

Just use the same size as your gas pipe if that is an imperial size (eg 3/8") then you may need an adapter.

 

Note this from the BSS :

 

Your choice, but this is what they say 

 

 

It is very important that fitting bubble leak detector on residential boats (and private leisure boats) is done by a LPG boat-competent Gas Safe registered engineer.

This is because the bubble leak detector must be correctly located and oriented, and for large volume LPG systems, the engineer may need to install a bypass arrangement to allow gas to flow past the detector when it is not being used.

ok... so i need to consider this a little more before diving in, thanks!!

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39 minutes ago, BWM said:

Have you sprayed the entire stop valves with leak detector? Have seen them leak in the handle pivot before. 

 

No I've only sprayed them on the upstream side. However with both isolators closed there is no leak registering on the bubble tester, so I'm assuming the leak is upstream.

 

25 minutes ago, David Mack said:

Basic question: How do you know you have a leak?  Does your bubble tester show a leak? How exactly did you perform the bubble test?

 

 

Yes the bubble tester shows a leak. I simply pressed down the red cap on the bubble tester. Is there another way to use a bubble tester?

 

I have to hold it down for about 30 seconds until a bubble appears every 10 seconds or so.

Edited by blackrose
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And do the bubbles continue if you hold it for longer than 30 seconds?  The problem with a short duration test is if the gas in the pipe is cooling for any reason it will be contracting, and more gas will pass through the bubble tester. So the result can vary according to the time of day.

 

Another possible cause of leakage is the spindles in the individual gas taps for each ring/oven/grill on the cooker. I know of a case where a boat failed a BSC manometer test, but after dismantling and regreasing the valves it passed with flying colours. Of course, as a liveaboard, you are not allowed to do that unless you are Gas Safe registered.

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1 hour ago, robtheplod said:

ok... so i need to consider this a little more before diving in, thanks!!

 

Or you could just dive in and do it yourself like some of us do. ?

 

It always makes me laugh when advice is given on this forum to use the services of a gas safe engineer, and then when the member asks for recommendations for gas safe engineers, the response is that there aren't many gas safe engineers who are allowed to work on boats! ?

 

I'm not familiar with exactly who's allowed to do what gas work and on what status of boat, but it's something like that. There does seem to be a bit of a contradiction.

 

7 minutes ago, David Mack said:

And do the bubbles continue if you hold it for longer than 30 seconds?  The problem with a short duration test is if the gas in the pipe is cooling for any reason it will be contracting, and more gas will pass through the bubble tester. So the result can vary according to the time of day.

 

Another possible cause of leakage is the spindles in the individual gas taps for each ring/oven/grill on the cooker. I know of a case where a boat failed a BSC manometer test, but after dismantling and regreasing the valves it passed with flying colours. Of course, as a liveaboard, you are not allowed to do that unless you are Gas Safe registered.

 

Yes the bubbles continue but I only continued the test for about a minute.

 

It could be the hob but again the leak is registering on the bubble tester with both isolators closed so surely it means the leak is upstream?

Edited by blackrose
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