Surveyor Ben Sutcliffe-Davies shares the simple checks you should do on board to make sure your gas installation is safe
When was the last time you checked your marine gas system and appliances ?
Several months ago I had to deal with the results of a gas regulator failing which caused a rush of gas to the cooker.
So I thought it would be good to put together a bit of a reminder about the importance of marine gas safety.
I don’t think a month goes by without me finding some serious marine gas installation issues on the boats that I survey.
Unfortunately, the safe installation of the gas system on board is still something that many owners don’t prioritise.
When undertaking pre-purchase surveys, it is worth pointing out that most surveyors are not considered qualified or have the latest certification in marine gas systems, but most should know what is and isn’t acceptable.
It is also worth highlighting that there are a growing number of marine Gas Safe engineers around the UK now.
Installing a marine gas system onboard
Unlike the installation of gas systems in a house, boat owners can fit their own gas system if they believe they are competent.
This is often the biggest single cause of problems.
As a result, when surveying a craft at pre-purchase or for an owner at the request of a boat insurance company, it is quite common to find a number of things wrong with the system on board.
Before starting inside a vessel, I often use a gas sniffer wand which can be bought for under £50 from places like Screwfix.
I would recommend investing in a proper gas bilge alarm if you have gas on board.
I know a good system isn’t cheap but it’s a serious life saver.
Below are a few areas that should be regularly checked, along with some explanation of what to look for and the risks.
I would strongly recommend having a properly qualified Gas Safe engineer, who is marine endorsed, examine your system or make changes.
The gas locker should be constructed in such a way to allow any gas escaping from the bottles or the pipework connections within the locker to be able to flow directly overboard, with no risk to those on board the vessel.
It is important to make sure that the structure that holds the gas bottle is appropriate and strong enough.
If using a steel box or GRP compartment, it should be completely airtight from the rest of the boat and should have an appropriate means of overboard discharge.
Some lockers will also require a second vent to allow better air flow too.
Ensuring the bottles are secure and the locker is quickly accessible is also very important; often I have surveyed boats where the gas locker is padlocked!
Regular maintenance of the marine gas bottle compartment, especially those 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 base of the locker is also helpful.
In some older yachts, the discharges for the gas locker can be found just on or just below the waterline; the latter is not appropriate.
Many rely on 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. Obviously, they should also be secure.
Gas is heavier than air but lighter than water, so if the discharge pipe is blocked, it will not be able to carry out any gas that is below the waterline.
Depending on your cockpit arrangement, there is then a risk that gas could end up in your bilges waiting for a spark.
I have several YouTube posts on gas lockers and failures, along with a simple bucket test with water to check the integrity of the gas locker.
Bottles, Hoses & Regulators
The siting of the gas bottles is quite important. Ideally, bottles should not sit in any standing water.
The compartment they are stored in should only be used for gas bottles, however tempting it may be to store equipment in the same area.
This will prevent anything deteriorating around them, holding damp and blocking the discharge drains.
Quick and easy 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 one metre long and carry a date on them.
They require frequent checking and should, in my view, be replaced every five years without fail.
Some argue that they are considered safe for 10 years but, Calor Gas disagrees, and recommends they should be replaced every five years as it is impossible to see internal stress and damage.
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. It is best to choose one with a large vent.
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The best regulator for marine use is one with a stainless steel innard and body unit, but this is not currently in production.
Regulators should be replaced around every five years as well; as one reader experienced, when it fails it will put bottle pressure down the system which will result in alarming flames when you turn on the cooker!
Keep an eye on the regulator condition – if there are any signs of corrosion replace it immediately.
These days, quite a few installers will fit a bubble tester to the regulator.
Again, make sure to fit and locate it in a position where it can be easily accessible, as all too often I turn up to survey a boat and find one fitted out of sight.
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 on the tester held down for about 30 seconds to a minute.
Gas flow is diverted through a bowl of glycerin and bubbles reveal an unsafe leak.
If this is the case, it would be wise not to turn the gas back on until you’ve had the whole system properly checked. Get in the habit of a weekly test.
Most modern appliances now require more gas.
The knock-on effect is that most new systems need to have a 10mm copper gas pipe as opposed to the more common 6mm runs that were fitted in most boats up to now.
Whenever the pipe work is passed through material, it is essential that the correct type of bulkhead fitting is used.
While mentioning fittings, it is worth highlighting that there have been a number of gas leaks on boats, where brass olives have been used in the joints instead of copper olives.
Any competent gas fitter should know to use copper olives; most DIY fitters don’t!
The pipe work should be properly supported to prevent it from movement or potential vibration fatigue.
Any appliance within the system should ideally have its own isolation tap nearby, within easy reach.
Checking pipe work can be done with gas leak detector liquid; try not to use washing-up liquid as it is quite corrosive.
Marine gas appliances
The location of appliances on a boat also needs careful consideration.
These days, a gas-fired water heater appliance can’t be fitted within a shower or bathroom without being contained within proper boxing.
Gas fridges are also no longer fitted in new-build boats.
For those on older boats with gas fridges, be aware of manufacturer recalls due to pilot light failures which happened in the 1980s and 90s.
I wouldn’t use a gas fridge any more. It is essential that cookers are correctly fitted. The rubber delivery hose should be armour hose, and again replaced every five years.
You will be amazed how often I find a 15+ year-old hose under a hob.
It is also important to make sure there is enough clearance above and behind the cooker so there is no change of setting fire to curtains and linings.
Checks save lives
I don’t think a year has gone past when I haven’t either dealt with or heard of at least four or five serious gas fires that were caused by either badly installed or poorly maintained marine gas systems.
Don’t forget to always treat gas with great care when it is not in use. It is best to turn it off at the bottle.
Try to regularly check the system and familiarise yourself with isolation taps and the general run of the pipe work.
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.
Do not stay on the boat until you think it is safe.
Buying a gas bilge alarm is a very prudent present for yourself and your family and friends.
As I always say, if in doubt get a professional out.
Enjoyed reading Marine gas safety: checks for peace of mind on board?
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