Originally Posted by David M
PVC pipe is fine for homes...
...Approved rubber exhaust hose is far more reliable than PVC for the same application.
It seems that you are talking about low pressure PVC pipe such as used for wastes, etc. as uPVC Pressure Pipe is not a simple home product as you claim. It is used widely in industry and is regarded as very reliable, often as being the most reliable (do a Google
search and you will see what I mean).
I do not have a paper copy of CFR Title 46 to hand (only the online version which is difficult to search) to look for the USCG requirements prohibiting uPVC from exhaust service
as you claim so would you refer me to the relevant section in that.
However, as you refer to USA requirements, I have reviewed the ABS Guide for Steel
Vessels Under 90m (it probably being a relevant guide as I recall
the Guide for Building and Classing Racing
Yachts does not specifically cover services) and there are no specific prohibitions of use of uPVC or in fact any other plastics in there that I can see, and does not differentiate between plastics - it concentrates on design about the mechanical properties of the plastic used, required chemical resistance and fire endurance (4-4-2 Table 2) just as it does for any other material.
Furthermore, it is a common practice of classification societies that they accept the results of proof by trial (and I have used the results of such trials to allow deviation from specific requirements in their rules for vessels entering class). In my own case I have a successful 11 year trial of uPVC to report showing no degradation whatsoever when cut into and filed compared to the new section I inserted to change the layout. Others I have discussed this with have found that information of interest.
It would seem that the original poster has not found exhaust hose as reliable as you claim it to be nor is it so in my own experience with delamination
and other failure very common. In fact the faults you claim for uPVC pressure pipe (brittleness, lack of universal chemical resistance, damage from stepping on, etc, etc) all exist for hose designed for exhaust service.
Your claim of insufficient chemical resistance of uPVC to substances it is likely to be exposed to on board surprised me as I can find no evidence that is so. It is certainly has a very high resistance to diesel fuel
, lubricating oils and in fact most other things apart from some solvents unlikely to be exposed to in a boat. Would you point me in the direction of your information that contradicts all that?
I have suggested an alternative and have now gone to quite some lengths to respond to your simple and unsubstantiated dismissals of it (my perhaps boring some
). People can take or leave that as they like as I am not going to test people's patience with it further here. However, I have found that people in the industry have not dismissed it as an option.
Getting back to the original question, uPVC is certainly fine for the temporary splice the poster wants to make and there is a wide range of suitable materials he can use for permanent rehabilitation (ALL with their own problems, with grp probably the best if cost is not a factor).