Sizing Gas Pipe

[Stemar]

I need to remove the gas locker on Jazzcat to allow access to the starboard engine. It's a royal PITA where it is as it makes checking the oil very awkward, so moving it to an aft locker which is already suitably ventilated makes sense. That will also give me room for a 10kg Flogas bottle, and make me fix the bodges I did to make the system safe (don't ask )

But... That will mean making up a new copper pipe with brass fittings. Running the pipe isn't a problem and I'm capable of making gas-tight joints, but sizing it is. I know there are various sizing - metric and imperial, and getting that wrong is obviously a bad idea. The following dimensions are all OD. The water heater, currently disconnected, has a 10mm pipe, the fridge, also disconnected, and cooker pipes are 6.44m, 0.253", pretty close to 1/4" Does that mean I have a mix of metric and Imperial pipes, or is there the gotcha that imperial is ID while metric is OD, like with some bigger pipes?

Supplementary question: Is 1/4" pipe, if that's what it is, big enough to feed both fridge and cooker (hob and oven) from the new locker to the existing pipework, around 3m, or should I go up a size? The pipework from the existing locker to the galley is inaccessible, so replacing the lot isn't practicable.

Thanks in advance!

 

[Boater Sam]

5/16" or 8mm ( almost exactly the same, ) will probably do the oven and hob, fridge is infinitesimal, over 3m run if there are no elbows or sharp bends. !/4" is too small.
Not uncommon to have a mix of metric and imperial.

 

[Caer Urfa]

On the majority of boats I survey 8 mm dia copper piping is used, as its all new suggest you also fit a 'Gas Bubble' gas leak detector into the pipeline !

 

[Boathook]

I renewed the copper pipe in my boat with 10mm copper. There were quite a few bends but it does feed the gas hob, grill, oven and fridge. I also used 10mm for my propex gas warm air heater.

 

[rogerthebodger]

If you have an instant water heater as I do I would go for at least 10 millimeter as the gas flow to the instant water heaters can be quite high and a smaller pipe would reduce the gas pressure and flow at the heater