MELTING DRAIN LINE

[MasterPlumbersKeymaster]

I work maintenance for a school system we have to schools just alike in one kitchen a steamer melted the drain line which is sch40 pvc we broke the floor and the line was broke out of the hub on the trunk line. We replaced it with sch40 pvc about two months ago now it is getting egg shaped at the hub that is sticking out of the floor. I looked down the pipe and the p-trap looks fine. The other school has the same steamer and drains into sch-40 pvc and the pipe has nothing wrong with it. Both schools are about seven years old, what should i do

[SylvanLMPParticipant]

Hey JS sounds like excessive temperature for this piping material wouldnt you say?

Have you considered either Galvanized wrought Iron or extra heavy cast Iron or if you folks really like using plastic why not lok into the following types

PVDF can handle high temperatures up to 280 Deg. F (137 Deg. C) and CPVC and PP can handle temperatures up to 210 Deg F (98 Deg. C).

Who ever told you folks to use PVC for this application needs a severe beating.

Must be an upstate NY Plumber LOL

[GuestParticipant]

Mr Sylvin you really sound like you know your plumbing, from the hub drain to the four inch combo is about twelve feet. If I use CPVC is twelve feet enough to cool the water before it runs into the trunk line,because it is SCH40 PVC to. Thanks for your help.

[SylvanLMPParticipant]

JS your very welcome BUT did you know some codes do not allow water in excess of 150 degrees to be dumped into a sewer line?

For example here in NYC we have the DEP and the plumbing department both have different dumping temperatures.

The main concerns are

1- The city employees getting scalded by the excessively hot water who may be in the sewer doing maintainence.

2- The hot water entering cold cast Iron sewer piping in the winter could cause severe cracking.

.You should also make sure this hot water does not comne into contact with any grease traps. Have a great one and be careful

[GuestParticipant]

Hey Sylvan It must be fun collecting all this knowledge huh?

Ever think of going on TV answering plummmmin questions LOLL.

I don’t know if you remember but about 2 years ago you gave me a great answer on how to pour a lead joint 3/4 under water without it popping. It did work like a charm.

My wife was from NYC originally before we moved and she loves your typical acid wit please keep it coming education with humor is a marvelous thing . Bob

PS Please can you sign me up to your PIPDL list I heard about?

[GuestParticipant]

SYLVIN, I still need to know if you think twelve feet is enough to cool the water before it dumps into the PVC trunk line. Also this steamer along with every thing else drains into a grease trap.What will this do to the grease trap.The town I live in is a small town in south Georgia, and believe it or not there is no inspections on anything but septic tanks. Thanks again,do you have a E-MAIL

[SylvanLMPParticipant]

quote:

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Originally posted by JS:
SYLVIN, I still need to know if you think twelve feet is enough to cool the water before it dumps into the PVC trunk line. Also this steamer along with every thing else drains into a grease trap.What will this do to the grease trap.The town I live in is a small town in south Georgia, and believe it or not there is no inspections on anything but septic tanks. Thanks again,do you have a E-MAIL

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Personally I would install a cold water line to temper the discharging hot water to about 105-115 degrees to be sure it was really cool before entering this plastic trunk line.

Plastic piping cannot take a lot of expansion and contraction as well as its metal counter part

Without knowing the actual volume and temperature and size and ambient temperature of the area It is impossible to say if it would be cool enough not to damage the main trunk lines.

McDonnell Miller does make controllers that I used on boiler blow downs as to sense the discharge temperature and it automatically opened a solenoid valve to add cold water to lower the scalding condensate to a safe level prior to it entering the main drain line used by the building (I used a tank for cooling down with an air gap to prevent any possibly cross connections)

Dumping excessively hot water through a grease trap renders the grease trap useless as it will melt the grease where it will flow out of this trap and congeal down stream causing you a lot of head aches later on plus possible fines.

. Check with your local code about the water entering a grease trap which must be under a certain temperature (Local codes do prevail) Your local DEP or sewer department can give you the exact temperature for cool down

Isn’t plumbing fun. I love commercial and institutional and industrial plumbing.

The residential plumbing I am sure would bore you to death.

I am sorry but even if I did give you my codes temperatures it wont help you even the NBBI or ASME or other ASSE code requirements as local codes love to get involved also.

What ever the code suggests for cool down try to make it a few degrees lower
Good Luck

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