B31.3 Testing Piping Sub-Assemblies

[TiCl4]

There is a point of B31.3 that I am not clear on. We are installing some new piping that will tie into current piping. The piping is fairly simple - just pipe, fittings, and valves. We will be doing a 1.5X hydro on the system, and had a question about when that test could be completed.

Must the completely assembled piping system be fulling installed before hydrotesting? I.E. must the entire system - all valves and piping segments - be in-place, supported, etc before hydrotesting? In this case, there would be pancake blinds to separate it from the already-installed header for the pressure test.

Or, could the piping be tested separately and before installation in the field? If so, could each piping spool be tested individually (each end blinded off and pressure tested)? Is this allowed under 345.2.3(a)?

If the latter method is allowed and done, is there any requirement for a leak test for the fully assembled piping system?

 

[LittleInch]

Short answer - first bit yes,

Second bit - it excludes having to do a full hydrostatic test to 1.5, but doesn't exclude a 1.1 or similar "leak" test.

Testing piping spools separately is quite normal and often required for equipment which although good for 1.5 for the body, the seals are usually only good for 1.1.

Most people are happy with hydrostatic test for 1.5 for the piping bits, put it all together then a leak test of 1.1 or an air test with soapy water to test the joints for leak tightness.

If you search on this site you will find lots of answers to your question.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[DekDee]

Interpretation: 20-24
Subject: ASME B31.3-1998 Addenda to 1996 Edition, and B31.3-2002 Edition, Para. 345.2.3, Piping
Subassemblies
Date Issued: May 20, 2005
File: B31-oS-1S7 and B31-oS-319
Question (1): Does ASME B31.3-2002 Edition define "subassemblies" the same way as it defines
"piping components"?
Reply (1): No.
Question (2): In accordance with ASME B31.3c-1998 Addenda and ASME B31.3-2002 Edition,
does para. 345.2.3(a) allow piping components to be independently tested as required by para.
345.1, and then assembled and placed into service with no additional leak testing?
Reply (2): No, unless the system is assembled with flanged joints or closure welds as described in paras. 345.2.3(b) and (c).

piping components: mechanical elements suitable for joining
or assembly into pressure-tight fluid-containing piping
systems. Components include pipe, tubing, fittings,
flanges, gaskets, bolting, valves, and devices such as
expansion joints, flexible joints, pressure hoses, traps,
strainers, inline portions of instruments, and separators.

IMHO no leak testing is required after final assembly