Sewer pipe engineering?

[Tom]

Jim I am looking at the same thing, but dont believe the
expansion/contraction is a big deal and nothing to worry about. I am going
to remove the present ABS pipes and install all new ABS pipes with electric
Drain Master valves. There is a slight expansion and contraction as you
noted but as Jeff Miller noted the tank is made of fiberglass , and I
believe it will flex a little itself. My present system is over 20 years
old and does not leak with one Dupree valve on the black tank and a Ventura
valve on the grey tank.

Tom Warner
1982 FC35
Vernon Center,NY
In the beautiful Mohawk Valley

At 12:10 AM 4/18/2005 +0000, you wrote:

>I have been doing some extensive research about ABS sewer pipe.
>(I know...I need to get a life!). What I learned is that ABS pipe
>contracts/expands 5 inches per 100 feet for each 10 degrees F.
>change in temperature. Applying this to the approximately 6.5 feet
>of pipe connecting the black and gray tanks, there is nearly 3/8 ths
>inch of expansion with 100 degrees change of temperature. It appears
>to me that this puts excessive strain on the tanks that could cause
>cracking. I am going to saw the pipes in too on each side between
>the dump valves and the 90 degree bend and reconnect them with
>flexible
>hose clamp type unions. I would appreciate some opinions pro and con
>if this idea is sensible? Also did all Wanderlodges come with the
>tanks plumbed together with no provision for pipe expansion or does
>mine have a non standard repair? Thanks
>
>Jim Keefauver/Jonesborough, Tn./1985 PT36
>
>