A moment to think about gas and your safety on board
Ben Sutcliffe-Davies celebrated 40 years in the marine industry in September 2018. He started boat building with his father and uncle and initially built wooden craft; over time he has also built craft in GRP, steel and aluminium. He has been a marine surveyor for more than 20 years and is now a full member of the Yacht Designers and Surveyors Association (YDSA) as well as of British Marine and the Inland Boat Building Association.
THE safe installation of the gas system on board is still something that many owners unfortunately don’t prioritise.
When undertaking pre-purchase surveys it’s worth pointing out that most of us surveyors are not qualified nor have the latest certification in marine gas systems. There are a few surveyors and BSS examiners who are also Marine Gas Safe engineers, but all of us should have a good basic understanding of what is and isn’t acceptable.
Unlike regulations for a house, you can fit your own gas system on a boat if you consider yourself competent! Bonkers or what! So, when surveying a craft at pre-purchase or for an owner at the request of an insurance company, unfortunately it is quite common to find a number of things wrong with the system on board.
I have put together a simple comment for each of the areas that really should be regularly checked along with some explanation of what to look for and why they are a risk. I personally strongly recommend having a proper qualified Gas Safe engineer who is marine endorsed. This would also be the right point in this article to ask if you have got a gas bilge alarm. I know a good system isn’t cheap but it’s a serious life saver.
Gas locker
The gas locker should be constructed in such a way that should allow any gas escaping from the bottles or the pipework connections within that area of the system to be able to flow overboard with no risk to those on board the vessel.
It is important to make sure that the structure that holds the gas bottle/s is appropriate and strong enough. If using a steel box or GRP compartment, check that it is completely airtight from the rest of the craft and that it has an appropriate means of overboard discharge. Some lockers also will require a second vent to allow better air flow too.
Ensuring the bottles are secure and the locker is accessible quickly is also very important. Often I have craft where the gas locker is padlocked or the bottles are actually floating around in the locker! Regular maintenance of the compartment especially with steel plating is very important and any corrosion should be dealt with quickly. Using something like a PVC egg crate or similar to keep the bottles off the locker base is also helpful.
It is a very common occurrence, especially with gas lockers on some of the older craft, for water to flow in and out of the gas locker all of the time. Some craft, particularly some of the GRP motor boats like the old Broads cruisers, have the discharges for the gas locker that are just on or just below the waterline, while some have hoses from the bottom that run down to the discharge.
It’s very important to make sure these hoses don’t get blocked or bent in such a way that they trap water and that they are obviously secure. It is worth remembering that gas is heavier than air but lighter than water so if for some reason the discharge pipe is blocked it will not be able to force it out if water is in the pipework for any discharge that is below the waterline. Likewise if there is any failure in the system the gas will end up in your bilges waiting for a spark.
Gas bottles
The siting of the gas bottles is quite important; ideally they should not sit in any standing water and the compartment they are in should really be purely for the gas bottles to prevent anything deteriorating around them holding damp and blocking the discharge drains, however tempting it may be to store stuff in the same area.
An easy and quick access to turn off the bottles is important; some owners use an electric solenoid as well. The connection of flexible gas hoses to the regulator should be done with proper approved hose stamped BS3212/2; these hoses should not be more than 1m long and carry a date on them; they require frequent checking and should be replaced regardless at five years from first use.
From the flexible gas hoses it is normal to have an appropriate regulator. The biggest problem with regulators in marine use is that almost every one will corrode at some point; choosing one with a large vent is better.
It’s important to keep an eye on the regulator condition and if there are any signs of corrosion, replace the regulator immediately. From the regulator quite a few installers these days will then fit a bubble tester; again it is important to fit it and locate it in such a position that it’s easily accessible. All too often I turn up at a survey and see that there is a bubble tester but can’t actually see it working properly because of where it’s been fitted.
If you have a bubble tester, ideally you should learn how to use it correctly; most rely on all appliances being shut off and then the button held down for about 30 seconds to a minute. If you see air bubbles then that would indicate there is a possible leak in the system, at which point it would be wise not to use it until you’ve had the system properly checked. Get in the habit of a weekly test.
Pipe runs
In recent times it’s quite noticeable that most modern appliances now fitted do require more gas; the knock-on effect of this is that most new systems fitted need to have a 10mm copper gas pipe as opposed to the more common 6mm runs that have been fitted in most craft up to now. It’s essential that wherever the pipework is passed through material that the correct type of bulkhead fitting is used.
While mentioning fittings I’m very aware that there have been a number of gas leaks on craft due to isolator connections where brass olives have been used instead of copper olives in the joints; any competent gas fitter should know this but most DIY fitters don’t! Also the pipework should be properly supported to prevent it from movement or potential vibration fatigue.
Any appliance within the system ideally should also have its own isolated tap nearby within easy reach. Checking pipework can be done with proper gas leak detector liquid. Try not to use washing-up liquid as it’s quite corrosive.
Appliances
Where appliances are located in the craft is also quite important. For instance these days, without proper boxing-in you cannot fit a gas appliance within a shower/bathroom.
Likewise, the fitting of a gas fridge in a new fit-out in the marine environment is no longer acceptable. For those of you who have some of the old gas fridges, be very aware of manufacture recalls that were undertaken in the ’80s and ’90s due to pilot light failures.
With free-standing cookers it is essential they are correctly secured. Wherever the location of the hub unit is, check how it’s connected. Some use a rubber hose to the underside that again requires replacement every five years; you will be amazed how often I find a 15-year-old-plus hose under a hob! It is also important to make sure there is enough clearance above and behind it not set fire to curtains, linings etc.
Summing up
I don’t think there has been a year go past where I haven’t either dealt with or heard of at least four or five serious gas fires that were caused by bad systems either installed or poorly maintained. Don’t forget to always treat gas with great care; when not in use, ideally it’s best to turn it off at the bottle. Try to regularly check the system and familiarise yourself with isolated taps and the general run of the pipework.
If you ever smell gas on board, turn the gas bottle off immediately and open all windows and doors – do not use anything that may cause a spark, including engines and light switches etc. Do not stay on the boat until you think it is safe.
As I said at the start of this article, the acquisition of a gas bilge alarm is a very prudent present to yourself and your family and friends. As I always say: if in doubt, get a professional out.
Check out the Ben Sutcliffe Marine YouTube channel for some video footage of bad gas lockers!