Plastic plumbing

[Rum Run]

So I am looking doubtfully at the water supply piping on the MAB, which is a mixture of copper and some PVC hose, and needs modifying anyway, and wondering if it is better to replace the lot with Speedfit PEX barrier pipe and associated fittings.
What are peoples' experiences and what size is appropriate. The system is only between tanks and galley at the moment but I might add a heads basin and perhaps a calorifier if I can find space.

 

[Rappey]

No comparison between plastic and copper.
Plastic does not "drum" can be easily fed through lockers and around beams, requires no more than a Stanley knife to cut it to size. Easily handles calorifier hot water. Easy to assemble and dismantle. No electrolytic transmission. Withstands at least 100 psi
Can't see you needing larger than 15mm

 

[Rum Run]

I assumed no larger than 15mm, but what about smaller? 10mm pipe has a bore of around 6.5mm

 

[Rappey]

It's availability of common fittings, such as galley pumps and cheaper domestic taps and shower fittings just happening to fit straight onto 15mm hardware. 10mm fittings may involve more legwork to find parts

 

[Rum Run]

Good point, I was wondering more about flow, but compatibility is a thing certainly

 

[Alfie168]

Plastic joints...like any other...are only as good as the person who makes them. I think Speedfit is ideal for boats. I would suggest investing in a plastic pipe cutter that cuts a perfect square cut across the barrier pipe. Knives can sometimes also leave a 'tag' that can damage the seal in the pushfit fitting. Another fairly common error is not inserting the pipe far enough. Pipes have markings on them to tell you when it is fully inserted in the joint. I'd just recommend people use the markers as they are there to help you, or to make your own mark with a pencil if you find yourself between marks on the pipe.

I'd also say that plastic ball valves are just as unreliable as metal ones. I've replaced two plastic isolator ball valves dripping (albeit on mains pressure) this very week. Neither was what you'd have called ancient.

10mm will probably be adequate for what you suggest, or you could start in 15mm and use 15-10mm adaptors to 10mm if you need wiggle room. Plastic pipe is wonderfully resistant to freezing as it will expand 3-4 times before it bursts. Plastic fittings are non expanding and can crack on freezing as I have found when people have piped up through lofts or in one case a commercial garage roof space, so you do need to drain down over winter ideally. If you forget you have a better chance of getting away with it.

 

[coopec]

Good point, I was wondering more about flow, but compatibility is a thing certainly

Best to stick with 15mm. As Rappey says 15mm fittings are available everywhere.

BUT Whatever PVC you use make sure it is Food Safe.
Is PVC pipe food-safe? (I hear polyamide is OK for food but not PVC.) - Quora


Larry Dynes, HVAC, Energy and Plumbing Retired (1971-present)
Answered June 22, 2017


Not all PVC pipe is food safe.

PVC pipe that is food safe is labeled NSF 51.

Be sure to review the manufacturer’s literature for suitable application, especially regarding temperature.

 

[Rum Run]

If I go this way I would be using one of the domestic water systems such as Speedfit or equivalent, available in Screwfix et al which are WRAS approved. NSF is a US standard I believe, though I would imagine no less stringent

 

[coopec]

If I go this way I would be using one of the domestic water systems such as Speedfit or equivalent, available in Screwfix et al which are WRAS approved. NSF is a US standard I believe, though I would imagine no less stringent

What is the difference between NSF-61 and NSF-51?
NSF-61 is the standard for “Drinking Water System Components-Health Effects”, and deals with materials and products used in contact with drinking water.
NSF-51 is the standard for “Plastic Material and Components used in Food Equipment”, and deals with materials and products used in contact with foods and beverages.

Explanation of WRAS approval for plastic pipe systems

 

[lw395]

I had a boat with plastic plumbing. I don't know the brand, not JG Speedfit.
Some of the joints seemed to leak a little over time, I put this down to stress and vibration. The pipe is stiff, it's not easy to keep all the 90deg joints unstressed in a boat, where nothing is at 90 degrees.
The boat did not have a huge water capacity or big calorifier.
I changed the plumbing to the shower and heads basin to 10mm speedfit, this eliminated a dozen joints as the 10mm is more flexible. It also meant less water was wasted running the hot tap to get warm water. Flow was adequate for a sensible shower not using too much water, but if you're used to abundant HW and power showers you might think it a little lacking.

If you can add a calorifier it is well worth it IMHO, going back to heating kettles to wash or wash up would not be my choice. You can keep the boat cleaner more easily with HW on tap. I'm all for camping on simple boats, but HW is the biggest plus in a cruising boat.

 

[ratbag]

multilayer pipe is currently the best on the market, however it required an expensive tool to crimp it , if done correctly it wont leak

 

[pvb]

What is the difference between NSF-61 and NSF-51?
NSF-61 is the standard for “Drinking Water System Components-Health Effects”, and deals with materials and products used in contact with drinking water.
NSF-51 is the standard for “Plastic Material and Components used in Food Equipment”, and deals with materials and products used in contact with foods and beverages.
View attachment 92083
Explanation of WRAS approval for plastic pipe systems

WRAS approval doesn't apply to boats.

 

[pvb]

So I am looking doubtfully at the water supply piping on the MAB, which is a mixture of copper and some PVC hose, and needs modifying anyway, and wondering if it is better to replace the lot with Speedfit PEX barrier pipe and associated fittings.
What are peoples' experiences and what size is appropriate. The system is only between tanks and galley at the moment but I might add a heads basin and perhaps a calorifier if I can find space.

Go for 15mm, as this is a standard size for push-fit plumbing used on calorifiers and water pumps. The Whale Quick Connect system is good, as is JG Speedfit. Don't worry too much about American standards, any decent system will be quite safe for drinking water.

 

[Cliveshep]

Why pay for barrier pipe? Are you running it through window boxes as it is designed for potable water pipes buried in the ground?
I would go with the 15mm system - everything you buy will fit and fwiw Aldi and Lidl often do a lovely range of mixer sink taps, basin taps and shower manifolds.

One word of caution - just because it is plastic it is NOT frost proof - drain out and blow out everything as part of winter layup. Shower mixer valves have modules that are destroyed by freezing - ask me how I know!

Siphon out your calorifier too - into the bilge if necessary and pump the bilge. If you add a drain-off connection to the calorifier during installation you can make life easier later on.

 

[Rum Run]

Why pay for barrier pipe? Are you running it through window boxes as it is designed for potable water pipes buried in the ground?
I would go with the 15mm system - everything you buy will fit and fwiw Aldi and Lidl often do a lovely range of mixer sink taps, basin taps and shower manifolds.

One word of caution - just because it is plastic it is NOT frost proof - drain out and blow out everything as part of winter layup. Shower mixer valves have modules that are destroyed by freezing - ask me how I know!

Siphon out your calorifier too - into the bilge if necessary and pump the bilge. If you add a drain-off connection to the calorifier during installation you can make life easier later on.

I had assumed all this sort of plastic pipe was "barrier" tbh, and price doesn't seem to be a problem at about a quid a metre: JG Speedfit 15BPEX-25C Push-Fit BPEX Barrier Coil Pipe 15mm x 25m and that is the posh range, Flo-fit is cheaper still.
Good point about frost, I will bear it in mind

 

[Boater Sam]

Pro rata 10mm fittings can be more expensive than 15mm. If its all 15mm then it will all fit other makes, Hep2o etc, and only one lot of spares.
Remember to fit the insert sleeves in the pipe at every connector. Use the inserts to match the makers of the pipe, its not all the same bore.
Do not cut pipe with a saw, it leaves burrs which cause leaks.

 

[lw395]

Pro rata 10mm fittings can be more expensive than 15mm. I...

But you may need a lot more of them if you need to route the pipe around awkward obstacles.

 

[coopec]

WRAS approval doesn't apply to boats.

I'm wondering why you say that.

I'm no expert but I am aware that not all tubes/[pipes are suitable for drinking water. If a product has WRAS approval on land why wouldn't it have approval on boats?

Can you elaborate?

 

[coopec]

Go for 15mm, as this is a standard size for push-fit plumbing used on calorifiers and water pumps. The Whale Quick Connect system is good, as is JG Speedfit. Don't worry too much about American standards, any decent system will be quite safe for drinking water.

You might be right but then again you may be wrong. (When it comes to drinking water I prefer to play it safe and use product that has been approved by a reputable body).

It appears the jury is still out but:

It is recommended that materials, chemicals, and processes connected to the home water distribution network are rigorously evaluated before use to determine the potential to cause significant levels of VOCs contamination. In addition, extending the curing period substantially reduced the degree of leaching of these organic contaminants from the PVC pipes into water. However, further work is necessary to investigate different contact periods and elucidate the role of disinfectants in altering leached organic compounds.
Leaching of Organic Toxic Compounds from PVC Water Pipes in Medina Al-Munawarah, Kingdom of Saudi Arabia

 

[coopec]

The Ductile Iron Pipe Research Association !!
The Dangers of Using PVC