How Safe if Your Yacht's Gas System? Part 3: System Components & Fittings

From BSS Guide Chapter 7

Following on from Part 2, which looked at gas bottles and bottle storage, we continue with a look at the various gas system components and what to look for to ensure that your system is up to recommended manufacturing standards (Part 1).

Regulators

The gas discharge is controlled by a regulator which essentially controls the conversion from liquid to gas form. The regulator can be fixed directly to the bottle, as is often the case in Europe, or to the side of the gas locker where it may accommodate more than one tank and allow switching between the tanks.  The switch may be a manually operated valve or a very low voltage electrical switch (solenoid) that operates automatically.

Regulator with Pressure Gauge

Regulators are available from Xintrex, or Trident through yacht chandlery shops in the Caribbean, or from Calor Gas suppliers in the UK.

It is recommended that some form of leak detection is included just after the regulator.  The bubble leak detector found in the UK gives a clear indication of any leaks in the system, although others are available in the US, linked to pressure guages.

Bubble Leak Tester Available from Socal.co.uk

Hoses, Pipework & Joints

1. The hoses between the gas bottles and the regulator are on the “high pressure” side of the system and hoses should be rated accordingly and no longer than 1 metre in length.  Check them regularly for signs of wear or damage which could cause a rapid discharge of gas into the locker.  Gas regulators have a lifespan and should be replaced every 10 years.
   
   
2. Gas pipework should be rigid and suitable for a marine environment, very often seamless copper tubing is used, although stanless steel and nickel alloy are also acceptable.  Pipes should be supported at least every 50cm to prevent vibration damage.  Check them regularly for signs of wear from vibration or other damage particularly where they pass through bulkheads.
   
   
3. Where it’s been necessary to route gas pipework through spaces containing a petrol engine or electrical equipment which has a higher probability of fire, there should be no joins in the pipe and it should be enclosed in a gas-proof conduit.
   
   
4. Heat can cause expansion & contraction of pipes, joints and through-bulkhead fittings causing additional abrasion at fixing points or cracks in previously sealed spaces.  Keep pipework at least 4 inches away from engine exhaust hoses and other sources of heat.
   
   
5. Where there has been the need to join pipes together, the joints should be compression fittings, easily accessible for checking and should not be at angles likely to suffer stress.  Pipe supports should be within 6 inches of the joint on all sides to prevent weakening of the joint by vibration.
   
   
6. Where there is a need to use flexible hose at the appliance, such as to the cooker, remember that these hoses have a finite lifespan and are particularly susceptible to abrasion.  Use ISO compliant hose, inspect it regularly and make sure that it has a grommet or sleeve where it passes through bulkheads or other partitions.  Hose connections can be made with correctly sized hose clamps on the low pressure side of the system; they should be checked regularly to ensure that clamps and hose remain damage free.
   
   
7. Any unused tails in the system should be securely plugged or capped.

The UK’s Boat Safety Scheme does not recommend the use of an “all hose” installation.

Shut Off or Isolation Valves

Manual Shut Off or Isolation Valve

1. If there is equipment on board that is frequently coupled and uncoupled to the gas supply.  There should be an appropriate bayonet or screw type attachment point with an integral shut-off valve.
   
   



From BSS Guide Chapter 7

2. There should be isolation (shut-off) valves in the system convenient to isolate each and every gas appliance, and immediately prior to the transition to a flexible hose attached to an appliance.  This enables an appliance to be isolated in the event of a fire, or if the hose needs to be changed or another repair made.
   
   
3. There must be a main shut off valve for the entire gas supply adjacent to the gas locker.
   
   
4. Gas shut off valves must be readily accessible and clearly marked.
   
5. A Gas alarm may connect to a low voltage gas solenoid switch to shut off the supply in the event of a detected leak.

Electrically Operated Gas Solenoid

Next: Part 4:  Leak Detection