Gas Fuse

[MtB]

Yes that's a medium pressure setup. Very rare. I've yet to encounter one 'in the wild'.

 

 

MtB

[MtB]

P.S. where is your meter box? It is supposed to be there protecting the meter from the elements!

(Or did you take it off for the foto?)

[Rose Narrowboats]

Bubble testers have relatively small porting through them, so can cause pressure drop on systems where there is high demand and as already pointed out will only tell you there is a gas leak if you are looking for one.

 

Some automatic changeover regulators used to have over pressure/under pressure valves built in so would shut off in the event of excessive demand (ie a fractured pipe).

 

Of the gas soundness tests we carry out that fail, probably 80% of them are down to leaky cooker valves. The soundness requirement is much lower for domestic installations, and the manufacturers view some leakage past the valves as acceptable. This normally ends in tears when a someone buys a brand new cheap domestic lpg cooker which ostensibly complies with the BSS (as they all do now) and it fails the soundness test. I've seen manufacturers then wash their hands of the problem because it meets their specs for domestic use - always get confirmation that the cooker you are buying is suitable to used in a boat.

 

If i were going to do anything it would be to fit a good quality gas alarm that could operate a remote solenoid to shut the gas off.

[Iain_S]

P.S. where is your meter box? It is supposed to be there protecting the meter from the elements!

(Or did you take it off for the foto?)

 

Taken off for photo

 

Iain

Yes that's a medium pressure setup. Very rare. I've yet to encounter one 'in the wild'.

 

 

MtB

 

Gosh, and here was me thinking they're all like that! Just shows how limited experience doesn't always translate into the whole wide world. (c.f. CC,CM, etc!!)

 

Ian

[mark99]

 

Not sure of meter type. They seem to be quite common around here, as when we had our CH boiler replaced recently, the plumber knew exactly where to look. I thoght they were standard; maybe it was a Scottish Gas thing ....

 

 

Not a Scottish thing as it's a National Spec for main gas. It's probably because there is less density of houses with plenty of outlying villages in most of Scotland so they distribute to houses in small pipes at high pressure to keep costs of mains distribution down. There is also a filter and a creep relief valve in your kit too.

[MtB]

Bubble testers have relatively small porting through them, so can cause pressure drop on systems where there is high demand and as already pointed out will only tell you there is a gas leak if you are looking for one.

 

Some automatic changeover regulators used to have over pressure/under pressure valves built in so would shut off in the event of excessive demand (ie a fractured pipe).

 

Of the gas soundness tests we carry out that fail, probably 80% of them are down to leaky cooker valves. The soundness requirement is much lower for domestic installations, and the manufacturers view some leakage past the valves as acceptable. This normally ends in tears when a someone buys a brand new cheap domestic lpg cooker which ostensibly complies with the BSS (as they all do now) and it fails the soundness test. I've seen manufacturers then wash their hands of the problem because it meets their specs for domestic use - always get confirmation that the cooker you are buying is suitable to used in a boat.

 

If i were going to do anything it would be to fit a good quality gas alarm that could operate a remote solenoid to shut the gas off.

 

 

I'd like to pick you up on that if I may. What do you mean by 'fail'? What is the specification of the test you are carrying out, and why are you choosing this specification?

 

I ask because on domestic installations there are two tests, one with appliances connected, and a second with appliances isolated. The first allows for a drop defined in a chart of appliances connected and varies with system volume. The second allows for no drop. As far as I can remember, PD 5482 uses a similar chart so if you are testing to PD5482, you are doing it wrong! There is an allowable pressure drop, with appliances connected even on boat installations.

 

If you are testing for BBS purposes, the design of the test might be different, but I doubt it. Maybe a BSS bod could enlighten us? I suspect the BSS says test according to the procedure defined in PD5482.

 

So just to expand on this, if a soundness test on a boat is being conducted according to BS 5482 and reveals no pressure drop, all well and good. If a pressure drop is revealed, one is supposed to look it up on the chart to see if it falls within the defined limits. If it does, then probably all is still well and good but a further test is required to confirm. A test with appliances isolated. Turn off the appliance isolation valves and test again. There should be no drop, thus confirming the network pipework is sound in which case the boat still passes the test. If there remains a drop, then the boat fails as a leak has been revealed on the pipework.

 

 

MtB

Edited February 21, 2015 by Mike the Boilerman

[Rose Narrowboats]

"Fail" as in doesn't meet the specification of the test our Gas Safe engineer is trained and qualified to carry out. Whatever that test is (see below) most leaks end up being traced to cooker valves rather than anything else on the system - food for thought when installing a gas alarm and depressing that a lot of these cookers are only a few years old.

 

I'm not qualified, so don't take this as direct from the horse's mouth: Assuming the system passes the let by test, the next test is a static pressure test (at 30mbar for 2 minutes, used to be 5mins I think). Gas Safe regs allow a certain pressure drop over this period (with the appliances connected) which varies according to the volume of the system as you describe for domestic installations ie a cruiser with 6 feet of 1/4" pipe will be allowed more pressure drop than a narrowboat with a 1/2" pipe down the length of it. On a like for like volume, the test is still more stringent than the domestic one, and of course lpg is more searching so any minor leakage on appliance valves will be exacerbated

 

BSS regs state that there must be no pressure drop at all over this period regardless of the size of the system. Then the arguments start over who takes precedence - the BSS or Gas Safe. Our registration is with Gas Safe, not the BSS, so we follow their rules.

 

I first saw this happen with a new cooker in the 90's when a small but reputable boat builder installed a very nice range cooker, made by a company who made stoves for the inland waterway market, into a boat he was building for a customer. The customer had supplied this range cooker along with assurances that it complied. The boat failed the BSS gas soundness test because of the cumulative effect of several small leaks on the cooker taps. The stove manufacturer wasn't interested as according to the information supplied it was within their tolerance for a domestic product and they didn't recommend it for a boat. The shop (NOT chandler) which supplied said it wasn't their fault as they had contacted the manufacturer and been told it was okay - but over the phone - so the argument went round and round. Ultimately the manufacturer had it back leaving a whopping great hole in an otherwise beautiful galley which had of course been built around this particular wider than standard cooker.

[Theo]

I think what these are intended for (catastrophic break of a pipe) is unlikely on a boat with no-one around... bilges tend to fill from slow leaks which this won't prevent and is why the recommendation is to turn off at the bottle(s) when not in use... although I am sure many don't even do that ... They can't be a bad idea to have though ...

 

Nick

We always turn off the gas at the bottles if we are not on the boat overnight.

 

N

[MtB]

BSS regs state that there must be no pressure drop at all over this period regardless of the size of the system.

 

 

Are you SURE about that?

 

Coz it's not what it says in my BSS book.

(Now I've checked I see my BSS book says test to the requirements of PD 5482-3, as I suggested earlier in the thread it might. PD 5482-3 gives a chart allowing pressure drops when appliances are not isolated. So I stand by my assertion your gas bod is doing it wrong.)

[Scholar Gypsy]

We always turn off the gas at the bottles if we are not on the boat overnight.

 

N

 

... and we always turn the gas off overnight if we are on the boat, using an easy to reach isolator valve on the outside of the front bulkhead.

[blackrose]

 

 

Sadly, no.

 

Bubble testers are fine in principle but they are rendered effectively useless by the stupid BSS rule governing where they must be installed. If they could be fitted in a convenient, visible and accessible position people might use them regularly. But the BSS demands they are fitted out of sight and out of mind, in a hard-to-see, hard-to-use location inside the gas locker. So they only get used once every four years during a BSS inspection.

 

Hands up who has a bubble tester in their gas locker, and they DO use it on, say, a weekly or more frequent basis...

 

 

MtB

I use mine every time I change or switch bottles.

[MtB]

I use mine every time I change or switch bottles.

 

 

One person so far!

 

Any more takers?

 

 

MtB

[Rose Narrowboats]

 

 

Are you SURE about that?

 

Coz it's not what it says in my BSS book.

(Now I've checked I see my BSS book says test to the requirements of PD 5482-3, as I suggested earlier in the thread it might. PD 5482-3 gives a chart allowing pressure drops when appliances are not isolated. So I stand by my assertion your gas bod is doing it wrong.)

I think you may have misread my post, he's Gas Safe registered and working to Gas Safe rules not BSS - which would appear to have been amended for the better since I last checked!

Edited February 23, 2015 by Rose Narrowboats

[MtB]

I think you may have misread my post, he's Gas Safe registered and working to Gas Safe rules not BSS - which would appear to have been amended for the better since I last checked!

 

I don;t think so!

 

The Gas Safe rules also have a chart of drops allowed when appliances are not isolated.

 

 

MtB

[Rose Narrowboats]

 

I don;t think so!

 

The Gas Safe rules also have a chart of drops allowed when appliances are not isolated.

 

 

MtB

Yes - as I noted in the second paragraph of post #32 "Gas Safe regs allow a certain pressure drop over this period (with the appliances connected) which varies according to the volume of the system"

 

Anthony

[Rose Narrowboats]

 

 

Are you SURE about that?

 

Coz it's not what it says in my BSS book.

(Now I've checked I see my BSS book says test to the requirements of PD 5482-3, as I suggested earlier in the thread it might. PD 5482-3 gives a chart allowing pressure drops when appliances are not isolated. So I stand by my assertion your gas bod is doing it wrong.)

Having just spoken to a current BSS examiner, he has stated that the BSS test is for 5 minutes plus a further 5 minutes with the appliances connected and any pressure drop whatsoever will result in a failure of the test.

 

This would be different in the case of a BSS examiner who is also Gas Safe qualified as he could swap hats and apply the Gas Safe rules. Then, so long as it passed the Gas Safe tests he could issue a certifcate that would then satisfy the BSS. This stems from a presumption that a BSS examiner is not trained and therefore not competent to decide what level of leakage is acceptable.

Edited February 24, 2015 by Rose Narrowboats

[MtB]

Having just spoken to a current BSS examiner, he has stated that the test they carry out is for 5 minutes plus a further 5 minutes and any pressure drop whatsoever will result in a failure of the test.

 

This would be different in the case of a BSS examiner who is also Gas Safe qualified as he could swap hats and apply the Gas Safe rules. Then, so long as it passed the Gas Safe tests he could issue a certifcate that would then satisfy the BSS. This stems from a presumption that a BSS examiner is not trained and therefore not competent to decide what level of leakage is acceptable.

 

 

I'm not going to labour the point any longer because you don't seem prepared to go and read the written test specifications, preferring to rely on what your BSS bod is mistakenly telling you verbally.

 

Your BSS bod is only carrying out half the test. If a small drop is found we must then continue and test again with appliances isolated. If no drop is found and the drop found initially with appliances not isolated is within the chart of values, the boat gas installation passes the test specified by BSS Office.

 

If your BSS bod failed my boat for a slight drop within the values specified for testing with appliances connected I would lodge a technical challenge with the BSS Office. Given the written test specification in the BSS manual, I'm confident I'd win.

 

The written test specification trumps the test your BSS bod 'says he does'.

 

MtB

[James Owen]

Sadly, no.

 

Bubble testers are fine in principle but they are rendered effectively useless by the stupid BSS rule governing where they must be installed. If they could be fitted in a convenient, visible and accessible position people might use them regularly. But the BSS demands they are fitted out of sight and out of mind, in a hard-to-see, hard-to-use location inside the gas locker. So they only get used once every four years during a BSS inspection.

 

Hands up who has a bubble tester in their gas locker, and they DO use it on, say, a weekly or more frequent basis...

 

 

MtB

Sorry Mike but this isn't wholly accurate.

 

There is no insistence by the Safety Scheme for bubble testers to be located "out of sight, out of mind" within the gas locker unless they are the sole means of testing for soundness of the LPG system.

 

Any safety minded boater who wished to fit one in a convenient, readily accessible location could do so without incurring the wrath of his or her local BSS examiner providing there were a test point elsewhere in the system.

[MtB]

Sorry Mike but this isn't wholly accurate.

 

There is no insistence by the Safety Scheme for bubble testers to be located "out of sight, out of mind" within the gas locker unless they are the sole means of testing for soundness of the LPG system.

 

Any safety minded boater who wished to fit one in a convenient, readily accessible location could do so without incurring the wrath of his or her local BSS examiner providing there were a test point elsewhere in the system.

 

 

Oh really, that's interesting. Thank you. Another myth busted!

 

I hadn't clocked the "unless they are the sole means of testing for soundness of the LPG system".

 

Puzzling why the presence of a separate test point should affect where a bubble tester can, or cannot, be installed though isn't it?

 

 

MtB

[MtB]

More:

 

Looking through my BSS Essential Guide, 2nd Edition 2005 I see no mention of any restriction on the location of a Bubble Tester. I always thought they had to go in the gas locker so now I have no idea where I got that requirement from.

 

Is it specified in writing anywhere? Any idea James?

 

 

MtB

[Rose Narrowboats]

 

 

I'm not going to labour the point any longer because you don't seem prepared to go and read the written test specifications, preferring to rely on what your BSS bod is mistakenly telling you verbally.

 

Your BSS bod is only carrying out half the test. If a small drop is found we must then continue and test again with appliances isolated. If no drop is found and the drop found initially with appliances not isolated is within the chart of values, the boat gas installation passes the test specified by BSS Office.

 

If your BSS bod failed my boat for a slight drop within the values specified for testing with appliances connected I would lodge a technical challenge with the BSS Office. Given the written test specification in the BSS manual, I'm confident I'd win.

 

The written test specification trumps the test your BSS bod 'says he does'.

 

MtB

It's not "my" BSS examiner - I can't help but feel that every time I answer your point you shift the goal posts slightly as we've moved from the original point that cookers are the greatest source of leaks via what Gas Safe engineer does to what BSS examiners do, which is nothing to do with me.

 

Just for the benefit of anyone else still reading I'm now in the office so have copies of the relevant documents to hand: 7.12.2 of the BSS guide 2005 states that where no bubble tester is fitted "have a competent person use the built-in test point(s) as detailed in Appendix C of the Examination Checking Procedures"

 

The only reference Examination Checking Procedures Appendix C makes to BS5482 - 3 is in C3 - Test Procedure: Let By Test where C3.2 states "Note regulator lock-up pressure (see BS5482-3 Table D.1)" .

 

Nowhere does it refer the examiner to make use of table C.1 of PD 5482-3 (Permissible pressure drop for test with appliances connected connected and LPG supplied by cylinder(s) or bulk tank installation pipework): The BSS "Checklist for privately owned and managed vessels" just has a yes/no box for whether it passes the defined test which is given in Examination Checking Procedures Appendix C Part 4 Test Procedure: Pipework leakage under C.4.9 as "There must be no discernible pressure drop" - none of this was altered in the 2013 revision so nothing has changed since I last checked.

 

hth,

 

Anthony

[raymondh]

Inst. instructions dictate where the leak detector will be effective I quote

 

1.

Select the model of leakage detector with suitable connections depending on the design

of the gas supply system. The leak detector shall be fitted after the regulator in the same

space as the gas bottle.

http://www.alde.co.uk/downloads/alde_4071_instruct.pdf

Ray

[MtB]

Check Page 4 of the BSS Essential Guide. First sentence.

 

"All LPG installations must meet the gas-tightness testing requirements of PD 5482-3"

 

The gas-tightness testing requirements are detailed in in Annex C of PD 5482-3, and included the drop chart the which I'm referring. I quote:

 

"Pipework should be tested as sound to ensure no discernible pressure drop. The permitted maximum
leak-rates and equivalent pressure drops for typical installations given in Table C.1 should be followed."

Note it says pipework should have no pressure drop. Appliances are allowed a pressure drop.

[Rose Narrowboats]

I've never disagreed that Table C.1 allows for pressure drop with appliances.

 

We're both outside our official spheres here but I would speculate that the issue is down to training - if a BSS examiner isn't trained as a Gas Safe Engineer, then is he competent to pronounce as to whether a system meets PD5482-3?

 

The examiner I spoke to was quite clear that they were told on the training course that they were not to carry out any tests beyond the initial test defined in the BSS Examination Checking Procedure* presumably because without a Gas Safe registrations they have no reliable means of demonstrating competence to do so.

 

*The test in full as defined is:

1. Ensure all appliances and main shut off valve turned off and appliance valves left on.

2. Turn on main shut-off valve and allow system to reach lock-up pressure

3. Close the main shut-off valve

4. Light one appliance burner and allow system to fall to 30mbar (propane) and 20mbar (butane)

5. Close appliance tap

6. Leave for 5 min for stabilisation and record pressure in 'U' gauge

7. Identify rise in pressure reading indicating main shut off valve let by has developed

8. Leave for a further five min and record pressure in 'U' gauge

9. There must be no discernible pressure drop in the system.

 

As you'll know, that procedure differs from the test defined in PD5482-3.

 

Anthony

[James Owen]

The scope of the examiner is determined by their training and the minimum requirements as set out by the Boat Safety Scheme.

 

An examiner must follow the applicability in accordance with each check.

 

Where the check requires 'no discernable pressure drop' then that requirement must be met in order for that examiner to issue a certificate of compliance.

If the test, on the face of it, reveals that there is a leak then a 'fail' must be recorded by that examiner and suitable procedures are then followed in accordance with his findings.

 

The examiner, as set out by the checking procedures and their role as a representative of the Boat Safety Scheme, is not permitted to apply those parts of PD 5482-3 allowing permissable pressure drops to which you refer as part of an examination.

 

The requirement PD 5482-3 is a Gas Safe regulation and as such, when applied by a Gas Safe engineer, may allow a pressure drop as per that requirement.

This is for the Gas Safe engineer to determine, not the Boat Safety Examiner.

 

How to reach a middle ground that proves satisfactory for all parties is a to and fro conversation that, I doubt, will ever be resolved.