PVC in High Rise Buildings

[rewatson]

A 40 story building has 30 office floors and 10 parking floors. Offices are Light hazard and parkings are Ordinary hazard 1. A listed plastic pipe can be used in office floors?.

 

[TravisMack]

Correct, you can use plastic pipe on the office floors. However, plastic pipe becomes a nightmare when you have to do tenant remodel as tenants come an go. If any way possible, I would recommend steel. It will make it much easier for the build outs later on. Also, with a building that high, you will have significant pressures at the lower levels. Be sure to avoid a series of 1" grid branch line piping on the lower floors. You can't use a mechanical tee to supply heads for the build outs down the road.

 

[rbulsara]

PVC Pipe for electrical work or mechanical work?

 

[rewatson]

Can I use SCH 10 pipe in each floor and SCH 40 in riser? The static head in some floors is almost 250 psig.

 

[TravisMack]

Yes...there is no reason that you couldn't use Sch 10 on the floors and Sch 40 in the riser...however, why? ..with the steel shortages (if you are in the US), Sch 40 is getting very tough to come by. Sch 30, 10 and 7 are rated for 300 PSI. I would say Sch 10 or 7 for the grooved piping and Sch 30 (one brand name DynaThread)for the threaded line piping. Use pressure reducing control valves at each floor where the pressure is in excess of 175 psi.

 

[rewatson]

I will use ECOH sprinklers heads (K=11.2)in parkings floors. I need help in sizing the pipe.

 

[TravisMack]

It requires you to perform hydraulic calculations to size the piping. You will want a software program to do that.

 

[MarauderX]

Be careful about using PVC piping in the plenum of the spaces, as it usually doesn't meet fire codes if the plenum is used for the return air.

 

[TravisMack]

Per the Blazemaster listing, PVC can be used in plenums as noted:
"Return air plenums with no set-back at ceiling openings per NFPA 90A "

 

[TSDavis]

Another consideration regarding PVC piping on the upper floors is that the pipe itself requires much more hanger support. Sometimes the spacing of the steel is such that it becomes larbor intensive. You can use drop in anchors (if the spec allows it)but still there will be many of them.

 

[TravisMack]

correct...the hangers are an issue. With the advent of the Sammy Xpress hanger, it is becoming less of a problem on upper floors. Also, with the volatility and availability issues of steel piping, I think we may be seeing more plastic jobs being installed.