Can I use standard ABS drain pipe to connect hose to holding tank??

[psneeld]

Eat more Mexican....

Till that winds up in a clog.... and then it may be worse .....

 

[rgano]

Greetings,

I'm plumbing my new holding tank and was wondering if there are any disadvantages to using standard ABS drain pipe fittings as pictured. The old tank had 90 degree hose barb fittings which were plugged when I pulled the tank. I thought this set up would lessen that chance- but being new, I don't know if this is a "no-no" or not. The pipe would be used strictly for the 90 degree turn (as shown) , a barbed fitting will be installed and connected to new Saniflex. Thanks!

I would suggest the inclusion of a short run of flexible sanitation hose at either end of any rigid pipe waste lines in a boat to mitigate the aforementioned potential issues with vibration and movement of the boat's parts. There are adapters made by one of the marine sanitation companies which glue to the rigid pipe and slip into the flex hose I believe.

 

[Bmarler]

Completely agree with Rich on that. There should always be a flex section between hard plumbing and it’s destination device. Not just for vibration mitigation, but for expansion and contraction due to temperature swings too. A one foot section is a reasonable choice.

 

[Davemwd]

Initially I was going to use barb fittings at the tank just after the 90s - then running flex line to each of the heads and the clean out. . But I like the idea of just using a 12" section of flex hose then back to the ABS - with a section of flex at the end point. I'll also use the adapters Rich suggests.

 

[luna]

If you are going to run hard pipe up to a foot or so from your 90º DWV elbow and use 2 barb fittings and a short piece of hose for the foot gap, why don't you just run the hard piping a little further and have the Sani/Flex hose replace the 90º DWV elbow?
Sani/flex is said to be able to bend at a radius of one hose diameter, for 1.5" hose thats a 2" radius. But Raritan also says the bend radius is 3.15". Hmmmmm?
Even if you said a radius of 4" and you could maintain adequate slope on the hard pipe it would be a cleaner install and one less barb fitting.

 

[HeadMistress]

I wouldn't buy hose or pipe from HD or Lowes because "household" pipes measure diameters differently than marine fittings. A marine hose size always uses the inner diameter, fittings always use the outer diameter, guaranteeing that a
1" hose will always fit onto a 1" fitting. That's not true of household fittings. A stated hose or fitting size can be either inner or outer, In the early days of holding tanks, all 1.5 fittings sold in marine stores were gray PVC sourced from household suppliers, and all of them used the inner diameter for their stated 1.5 hose fitting size, creating an outer diameter that was impossible to put a hose onto without heating the hose or sanding the hose barb, either of which often resulted in a torn hose. Moral of this story: stick with marine fittings and pipe. If you must use pipe, use schedule 80.

--Peggie

 

[luna]

The terms Schedule 20, 40 and 80 refer to pipe with increasing wall thickness so that they can withstand higher pressures. Outside diameter remains the same so that the tradesmen can use the same thread cutting equipment on all schedules of pipe. Naturally the ID of Schedule 80 pipe is smaller than that of Schedule 40 pipe.

This originates back in the 1920's when steel was commonly used for piping as plastics were not yet developed. Plastic pipe I think just use the same dimensions as their steel counterparts and therefore the manufacturers can call their plastic pipe Schedule 40 or 80, but due the material these plastic pipes won't withstand the same pressures as steel pipe.

Pipe fittings are available in the appropriate wall thickness (or Schedule) for many different pipe materials.

Hose is usually measured by inside diameter where tubing is likely defined by its outside diameter. Hose barbs fittings can have the same or different sizes at each end, one for the hose and one for the threaded connection to the pipe.
If in the early days the hose barb fittings stocked at your local chandlery would not fit the hose, why would you buy them?

I know of nobody who measures "household pipes" differently than marine pipes. In fact I know nobody who actually offers you the ability to "stick with marine fittings and pipe". Can you provide a manufacturer or source of marine pipe in useful sizes for this audience?

 

[ranger58sb]

This originates back in the 1920's when steel was commonly used for piping as plastics were not yet developed.

Hose is usually measured by inside diameter where tubing is likely defined by its outside diameter. Hose barbs fittings can have the same or different sizes at each end, one for the hose and one for the threaded connection to the pipe.

I've only developed a very hazy view of the difference between hose and tube. But I did measure to learn the OD of our existing 1/2" ID "rubber" hose is 3/4" whereas OD for 1/2" PEX (previous boat) is 5/8.

I also eventually discovered that the outside diameter of a standard barb for 1/2" (ID) hose is different from the outside diameter of a barb for 1/2" (ID) PEX. Former, near 13.5mm, latter slightly under 12mm. And that in turn meant different cinch clamps.

The plumbing part of my whole water heater replacement project kicked my a$$ for a few weeks...

-Chris

 

[Wtrguy]

I also eventually discovered that the outside diameter of a standard barb for 1/2" (ID) hose is different from the outside diameter of a barb for 1/2" (ID) PEX. Former, near 13.5mm, latter slightly under 12mm. And that in turn meant different cinch clamps.

I believe PEX is proprietary and doesn't play well with anybody else. Has anyone ever seen PEX fittings used with other (non PEX) kinds of material successfully?
My career was spent in the municipal water/wastewater industry. In my experience pipes are typically listed by ID. There are still some outfits that produce OD Steel pipe but it's getting more rare to find it in use.
All that said, I'm pretty new to plumbing on boats so I'm excited to learn the differences. One thing I know for sure is there is always some old fitting from some defunct manufacturer somewhere that can't be replaced/reproduced, and then the design/retrofit fun starts!

 

[SteveK]

I have found that all pipes are not the same, as in fittings and ID size. THIS LINK shows it well. Using plastic pipes seems to give enough leeway when pipe is heated.

 

[Sleeping Bear]

I've plumbed two boats with 1 1/4 abs or pvc (depending which was available, ABS is easier, no purple catalist) and they worked great. For flex couplings I used 1 1/2 sanitary hose which I got to fit by heating it in very hot water. Do not use fernco couplings as they stink very quickly.

 

[kapnd]

I would suggest the inclusion of a short run of flexible sanitation hose at either end of any rigid pipe waste lines in a boat to mitigate the aforementioned potential issues with vibration and movement of the boat's parts. There are adapters made by one of the marine sanitation companies which glue to the rigid pipe and slip into the flex hose I believe.

I agree, and I’d start with a short flex portion right out of the tank.

I've plumbed two boats with 1 1/4 abs or pvc (depending which was available, ABS is easier, no purple catalist) and they worked great. For flex couplings I used 1 1/2 sanitary hose which I got to fit by heating it in very hot water. Do not use fernco couplings as they stink very quickly.

The purple liquid is cleaner/primer for PVC, not a catalyst. Rub it on vigorously until the printing on the pipe is gone to assure that the glue penetrates past the hard glaze on the pipes (and fittings) surface.