Steam Pipe vs. PVC Pipe

Long Beach Ed

On this job, a 1-1/2" PVC drain crosses directly over a 1-1/4" steam steel radiator runout at right angles. They nearly touch other. The intersection will be in an inaccessible ceiling.

We're imploring the plumber to use copper or galvanized for the drain. He thinks a sheet of rubber or half-inch Fibreglas insulation will suffice. We know it will not.

Any thoughts or suggestions here?

A good New Year to all our Wall old friends.

realliveplumber

Demand a section of copper tubing. Also shielded elastomeric couplings. "Pro-flex" is one manufacturer.

It wont cost more than $30.00 or $40.00 in materials, whats the big deal?

EBEBRATT-Ed

Let it melt if he is so smart he will be back there fixing the pipe and the ceiling

SteamingatMohawk

If he hasn't skipped the country! LOL

Long Beach Ed

The plumber does not want to put the rubber couplings under a concrete floor, he feels they'll trap hair and mung in the drain line which is a 1-1/2" shower drain. Doesn't have room to upsize to the 2". That's why I suggested copper.

dko

Nvm

ChrisJ

I have a 3" PVC drain for a toilet that basically is touching a 1 1/4" steam pipe directly under it.


I don't like it.
But it's been there for at least 20 years from the look of it and it's still ok.  I was told it was done in 1987 but I'm not entirely sure I believe it.

I'm not saying it's right or that I would ever do it.  I'm just reporting the results so far.  For me it's one of those "I need to fix it but it's not complaining so I'm leaving it alone" situations.

hot_rod

any air gap will keep the pvc  from seeing the steel pipe temperature. 160- 180 is the melt point of PVC pipe. Certainly a section of copper  would eliminate the potential for a problem

pecmsg

Long Beach Ed said:

The plumber does not want to put the rubber couplings under a concrete floor, he feels they'll trap hair and mung in the drain line which is a 1-1/2" shower drain. Doesn't have room to upsize to the 2". That's why I suggested copper.

so this is all underground?

SteamingatMohawk

@Chris Get out your handy dandy infrared laser thermometer and measure the temperature at the connection of the two pipes and let us know. Send us a pic, too.

ChrisJ

SteamingatMohawk said:

@Chris Get out your handy dandy infrared laser thermometer and measure the temperature at the connection of the two pipes and let us know. Send us a pic, too.

It's in a nasty low crawl space.

Id gladly normally help out but for this I'm sorry.  I don't go in there unless I have no choice.


That crawl space is Ravenholm.

Long Beach Ed

It's in a second floor bathroom floor. Above the pipes will be a mud slab between joists. On the joist bottoms is a plastered ceiling on wood lath.

In this photo, the steam pipe will be relocated at right angle in the bay between joists below the drain. The drain will be replaced by PVC. A new subfloor will be placed atop them. (Anyone spot the hole in the steam nipple?)

EBEBRATT-Ed

If it is closed in with a ceiling above and below the pipes and the air can't move it may overheat the PVC.

In @ChrisJ case in a crawl space where the air can move its probably not an issue with some miminal clearance.

pecmsg

Long Beach Ed said:

It's in a second floor bathroom floor. Above the pipes will be a mud slab between joists. On the joist bottoms is a plastered ceiling on wood lath. In this photo, the steam pipe will be relocated at right angle in the bay between joists below the drain. The drain will be replaced by PVC. A new subfloor will be placed atop them. (Anyone spot the hole in the steam nipple?)

There a lot of structural issues to deal with. 

Don’t ask the plumber tell him you want copper below the floor. 

Long Beach Ed

We're just doing the heating... The floor is being placed on 1-1/2" "sleepers" above the joists, leaving some more room to work with for the heating runout. Yes, a structural challenge, as this old work always seems to be.

Good thought about the trapped heat in the enclosed space...

realliveplumber

We see that all the time. Most of them have the tops of the joists with a 45 degree hand hewn bevel. The idea was that it cement would apply pressure laterally and transfer the weight to the bearing walls.

We usually sister plywood, or dimensional lumber, and rough in conventionally drilling through the joists. Then glue the snot out of plywood or Advantec.

Long Beach Ed

Yes, Reallive, I've often wondered why they dumped a thousand pounds of concrete between the joists only to have a 3/4" ribbon of it above the beams... It served several purposes perhaps. I guess when you carry 400 pound tubs and radiators all day, mixing sandy mortar is easy work...