Gas installations

[MtB]

I'm part way through re-fitting the galley/saloon area of my narrowboat and rather than alter the gas pipework (with the extra joints this will involve) I'm intending to start again from scratch with all new pipework.

 

It is a requirement to minimise the number of joints in a system, and the conventional arrangment of a single pipe entering the cabin space and going from appliance to appliance with compression tees and isolating valve by each appliance introduces a larger number of compression joints into the cabin space. All have the potential to leak, and often do in my experience of boats.

 

To minimise the number of joints inside the boat and enhance the safety of my new installation I'm planning to use a 'star' format for the new pipework. This will involve a manifold fitted in the gas locker or front well of the boat, connected to the gas regulator outlet. The manifold will have four outlets with isolating valves, one per appliance. This way I can run a separate pipe to each appliance with no joints inside the cabin space except where the tubes connect to the appliance inlets.

 

Has anyone else installed a gas system designed this way, or have any comments please?

 

Cheers, Mike

[Guest]

I have read that this is the standard way of doing the job in the USA, but I cannot remember where. It would seem better since as you say there will be no tee joints in the boat (one leaked on our last boat) plus you should be in a better position re. gas pressure BUT CHECK WITH THE BOAT SAFETY MAN FIRST! Another thing I hate are those bulkhead fittings-two more joints in the boat that you don't want! I know some boatbuilders who bore them out to the diameter of the pipe and hence the pipe passes through without a joint and just acts as a sleeve. Wether this is legal I don't know, but I feel it is better than having two extra joints. I believe it is legal to use plastic sleeve so I cant see the difference but again CHECK WITH THE BOAT SAFETY MAN!

[John Orentas]

Mike.

 

I think your idea for a 'star' piping system is an excelent one, any leaks which develop are most likely to be in the vented gas locker. Have you got the 'Boat Safety Scheme Guide' titled 'The Essential Guide' Red coloured January 2002, I would advise you to get one if you haven't already. If you stay stricktly with the book you can't go wrong. After all that is what the inspector will do.

 

I was going to add a caviat that cut-off taps need to be fitted close to the appliance, but having checked they can be fitted on or close to the manifold. It might be an idea to fit a Bubble Tester with your bottles to avoid any possible anomoly.

 

Stans' idea for doing away with the bulkhead connections is a good one too, in fact there is a picture in the book of an alternative 'grommet' protecting a pipe going through a bulkhead.

 

You are likely to have many replies from 'Corgi men', most of whom seem to imagine that only they have the skills and expertise to install gas systems on boats, I am sure that this is not so.

 

John Squeers

Edited October 14, 2004 by John Orentas

[dor]

I think passing the pipe through the bulkhead by for example drilling out the normal bulkhead fitting is not uncommon. You have to seal it though with a flexible sealant so gas can't go through the hole as well, and to prevent pipe vibrating against the metal.

[Rick]

The guy, qualified installer of gas on boats, who fitted our supply pipe used a bored out bulkhead fitting and then nipped up one olive to stop movement. No joints and no vibration. Seems good.

 

Richard

[Paul Evans]

I'm not a CORGI man but I would recommend that you use one to install your gas system. The star and bulkhead boring ideas looks good and I'm sure a CORGI fitter would see the benefit of reducng the number of connections in the cabin.

 

The advantage of using a CORGI fitter is that you should get someone who understands the danger of gas in boats, knows the standards that should be applied and will provide a skilled service. I say "should" because there are cowboys out there so you will need to ask around to find somebody you can trust. Personal recommendation based on solid experience is always best.

 

Whatever you decide to do, get your Boat Examiner involved at an early stage. It's so much easier to get a Boat Safety Certificate if the examiner knows what you have been doing.

[John Orentas]

Paul.

 

I agree with very little of what you say.

 

You rather missed the point of Mikes original thread. It is that you will drastically reduce the number of connections in the cabin areas. It is not only CORGI fitters who understand the dangers of gas, most competant people will have a good understanding of what is required in a gas installation.

 

The Boat Examiner is just that, an examiner he has taken a two week course. The installation standards are very well set out in the 'Guide Book', it is well written and easily understandable.

 

If the gas installation has been carried out competantly, the inspector will pass it. He does not need to be involved at any stage other than to carry out his test and inspection.

 

John Squeers

[Paul Evans]

I did recognise the advantage of reducing the number of connections in the cabin - having had some leaks in my boat, I would adopt these ideas if I were building/refitting.

 

I agree that competent people recognise the risks attached to gas in boats but I was suggesting that you should be looking for somebody who recognises the risks and understands the standards and has the skills to complete the task to those standards. If you believe you meet all three then go ahead.

 

Most boat examiners are not just people who have gone on a two week course to get a certificate that allows them to carry out an inspection and if they were I would avoid them like the plague. I look for an examiner with wide experience of narrowboats and who will bring an objective eye to my boat. I want to know that it has been inspected by more than a 'jobs worth'. Fortunately, most examiners do take a real interest in boats that goes beyond the cash certificates can generate.

 

If I were an examiner and knew that the gas installation had been put in by somebody without a CORGI certificate, I would be takng a very close look at it. After all, the boat safety certificate process is not just about protecting the owner but about other users as well. A gas explosion can go well beyond the boat itself. I am just suggesting that involving your examiner at an ealy stage could pre-empt enquiries and adjustments to the system later - saving time and effort all round. There is no requirement to invole the examiner - I just think it makes sense.

Edited October 14, 2004 by Paul Evans

[Big COL]

Can I just qualify what you refer to as bored out fittings. A gas bulked fitting is specifically designed for that purpose, it allows the pipe to pass through unbroken and has a compression olive and nut on both ends, so when the installation of the pipe is complete, they are then tightened to prevent any chafing on the pipe. Stan said he hates these bulkhead fittings - two more joints than are needed. I am almost certain Stan that you are refering to a normal gas bulked fitting but because there are compression nuts on both sides you think it's being used as a straight connector. I canot imagine any surveyor passing any gas installation with a joint through a bulkhead. If that is the case I'm glad it's not on my boat and would advise that you get some clarification if this is permissable, bearing in mind that the inside part of the bulkhead fitting is usually buried in the insulation and is difficult to reach.

[John Orentas]

None of the pipework should be 'buried in the insulation'. All parts of the pipework should be accessible for routine examination.

 

There is no requirement to make a seal where the piping passes through a bulkhead, nor does the pipe need to be continuous. The recommended grommet is to protect the pipe from abrasion.

 

 

John Squeers

[Big COL]

None of the pipework should be 'buried in the insulation'.  All parts of the pipework should be accessible for routine examination.

 

  It is but if the pipe was not continuous then the inner conection will be inside the insulation of the bulkhead which means if it's spray foam you will need to remove a considerable amount to effectivley make the joint and to leave it visible for further inspections. this to me is wrong and if not certainly not best practice to have a joint at a bulkhead. Best practice would be to pass a continuous pipe through a proper bulkhead fitting which has compression olives on it which stop the pipe from chafing. I know you can use a grommet but people then tend to use anything to hand (e.g. bits of rubber hospeipe etc.)

 

 

There is no requirement to make a seal where the piping passes through a bulkhead, nor does the pipe need to be continuous.  The recommended grommet is to protect the pipe from abrasion.

John Squeers

<{POST_SNAPBACK}>

 

 

  This statement is definitely wrong and dangerous - what you are telling people here there is no need to make a seal with a non continuous pipe. I think in the nature of the serious consequences that could result from this sort of information the thread should end here and a reply from professional Corgi registered engineer obtained before someone has a serious accident. Sorry to be blunt but gas in boats needs the utmost respect. Installed properly it is perfectly safe.

Edited October 13, 2004 by Big COL

[John Orentas]

Big Col.

 

I think perhaps you should re-read my reply before getting hysterical about this matter. The 'Seal' in this context is obviously not refering to the integrity of the pipe but the closure of any atmospheric passage from one side of the bulkhead to the other.

 

A bulkhead fitting invariably involves the interconnection of two tubes, one at each side of the bulkhead, in this case by compression fittings. The modification of a standard gas fitting by drilling through it is not good practise.

 

Indeed for the application in question a bulkhead fitting is not required at all, as I pointed out in my previous reply a simple grommet is all that is required.

 

For the record I am a professional engineer who has spent a couple of decades of his life designing instrumentation, a fundamental part of which involved the hermatic sealing of gasses within enclosed spaces.

 

I notice that you 'Quote' my words in your reply. I would request that in future you make it clear where my words end and your 'considered comment' begins.

 

John Squeers

Edited October 14, 2004 by John Orentas

[Gary Stacey]

I used a cable gland to seal the pipe through the bulkhead. The pipe passes straight through and you can compress the rubber sealing washer on the pipe to create a perfect seal.

 

gary

[Big COL]

This is my last post on this subject as I have no intention of entering into a slanging match over this as it is too serious in the aspect of safety to allow it to become protracted. As a qualifed engineer that you are, and knowing the hard work that was required to become one I would have thought that you would have shown some respect to your fellow engineers,a boat inspector to my knowledge and experience is far from some one who has read the book and completed a two week course on each subject. I have found them to be extremely knowledgable and practical, I should imagine that they will take a dim view at your perception as to how they acquired their considerable knowlege base.

As a qualified Electrical/Mechanical engineer who in 42 years working experience has covered many Boiler,Pneumatic,Hydraulic,Gas,and Water, installations, and although being at director level, I am still totally hands on, (by choice) I feel I have gained enough experience to have a valid opinion on this subject. If you had witnessed some of the horrific D.I.Y jobs not just on boats that I have you also might have a change of heart.

As you are well aware,but for the benefit of those who are not, you do not have to be CORGI registered to do any gas installation on your own boat it just has to be inspected and passed on completion,by a CORGI qualified surveyor unfortunately there are some, that forego this inspection and it is these few who cause the problems for the rest of us, of course there are plenty of very competent D.I.Y. who make a very professional job of their work, but as with all things in life it's the rest of us who have to be protected from the idiots.This was one of the reasons CORGI was originally started to have safe standards and get rid of the cowboys. If you consider this to be hysteria then so be it,but you can still show your fellow engineers the respect they're entitled to.

[MtB]

Thanks for your replies everybody. Plenty to think about there then! A few comments...

 

1) To the people who advised getting a CORGI bloke in, it just so happens that I am competent to do gas work on boats, in the eyes of the law. I have the appropriate ACS passes to enable me to do gas work on boats and my business is CORGI registered. Trouble is, the ACS exam training taught me the theory but not much in terms of general practice or ways things are done in a real narrowboat installation.

 

2) Bulkhead fittings: A really BAD idea in my view. As others have said, cutting a pipe and joinging it together again just to go through a bulkhead is just adding unnecessary joints to leak. I've only worked on two boats since quailifying to do boat LPG and bothe had gas leaks on compression fitttings. One was a cooker tee and the other was a bulkhead fitting. And I was always finding compression joint gas leaks on boats at Windsor Marina when I worked there 20 years ago before all this CORGI stuff.... The rule is that a pipe passing through a bulkhead must be effectively protected from chaffing or damage IIRC... so a good quality grommet will do, or a bulkhead fitting drilled out to take an uncut pipe is excellent. And I particularly like the cable gland idea from Gary.

 

3) Thanks for the comments about asking a boat safety inspector. An installation can be gas-safe from a CORGI point of view and still fail a boat safety inspection. AND vice-versa. (Flue termination for example is a Big Thing in the CORGI world, but boat safety inspections don't seem too concerned. Mushroom vents on water heater flues are NOT ok, for example! ;-) )

 

4) Bubble testers. Great idea (I think) although I've yet to see one. (They give visual indication with bubbles in a fluid, of the presence or absence of a leak in the system anywhere doenstream of the tester.) I'll be fitting one on my own boat to assess it. I'll comment here again when it's in use.

 

Cheers, Mike

[Guest]

I can only assume that there are different bulkhead fittings than the one I bought, but it DID require that the pipe was cut-it clearly will not pass through. Rather than use that I used a plastic sleeve plus sealant (high temp silicone) and yes the idea of a cable gland seems excellent -you would think I would have thought of that being as I am an electrician! Drilling the bulkhead fitting it appears is fairly standard having asked around.