Feedwater Piping

[ghmail]

Hello All,

We are having a contractor replace the feedwater piping between the feedwater pumps and the boilers. The feedwater is at 200 deg. F and 200 psig.

Is schedule 40 steel pipe adequate or is schedule 80 required?

I do not have a copy of ASME B31.1 available at this time, but it is on order.

Thank you.

 

[rustbuster]

You need to include diameter, corrosion allowance, fluid velocity, materials of construction, in you query to calculate tmin,

 

[ghmail]

Thanks rustbuster.

The pipe is 4-inch diameter black steel, velocity is 10 fps, corrosion allowance of 10 percent.

 

[davefitz]

unless you have a relief valve directly connected to the piping, you would need to use a design pressure equal to the pump's "dead head " pressure minus 10% ( B31.1 loophole for overpressure). Check the pump's Q vs H performance curve at Q=0 gpm .

 

[Duwe6]

If your max pressure is 450 psig or less [based on PRV or pump] then Sch40 is a good choice if you have good control of BFW chemistry. Sch40 will not give very much Corrosion Allowance - C.A.

 

[europipe]

You are working without pipespec.?