Relief Valve Discharge Pipe Reduction?
Relief Valve Discharge Pipe Reduction?
(OP)
all,
while i am investigating the asme code, i believe a knowledgeable individual can provide a quicker response and possibly direct me to the location within the code - hopefully that is!
equipment is boiler drain heat recovery unit.
relief valve size is 1-1/4" x ? with 4" vent piping to bldg roof and then reduced to 1-1/4" for roof penetration.
i know from experience that reduction of or restricting vent piping is not permitted as it defeats the purpose of the relief valve - a personnel and equipment hazard!
anyone with direction to specific section within the bpv code or international mechanical code is appreciated.
-pmover
while i am investigating the asme code, i believe a knowledgeable individual can provide a quicker response and possibly direct me to the location within the code - hopefully that is!
equipment is boiler drain heat recovery unit.
relief valve size is 1-1/4" x ? with 4" vent piping to bldg roof and then reduced to 1-1/4" for roof penetration.
i know from experience that reduction of or restricting vent piping is not permitted as it defeats the purpose of the relief valve - a personnel and equipment hazard!
anyone with direction to specific section within the bpv code or international mechanical code is appreciated.
-pmover





RE: Relief Valve Discharge Pipe Reduction?
asme bpv code section 8, part ug-135, ug-136, and appendix m.
-pmover
RE: Relief Valve Discharge Pipe Reduction?
As additional reference, you may also want to look at the American Petroleum Institue recommended practices for relief system design, API RP-520 Part I, Section 3.3 discussion on back pressure and API RP-520 Part II, Section 3 disccusion on relief device discharge piping.
API also lists some technical interpretations of these recommended practices on their website. Take a look at the following link which I think addresses your question specifically. The technical interpretations are given in Excel spreadsheet format, look at the discussion on row 11.
http://committees.api.org/standards/tech/docs/520bti.xls
RE: Relief Valve Discharge Pipe Reduction?
RE: Relief Valve Discharge Pipe Reduction?
RE: Relief Valve Discharge Pipe Reduction?
thanks for the link information.
unclesyd and bdog,
i wholeheartedly concur with your assessments, but i would not (ever!) recommend a piping reduction in relief valve discharge piping, even if the calcs support the reduction. the only justification i can see is cost-savings (not a technical decision!), which is a poor decision.
-pmover
RE: Relief Valve Discharge Pipe Reduction?