ASME B31.1 Section 122 / ASHRAE Handbook

ASME B31.1 Section 107.2

A check valve installed backwards blocks forward flow and allows reverse flow — the exact opposite of its purpose. Flow direction arrow must match the piping flow direction.

ASME B31.1 Section 114

ASME B31.1 requires welded or flanged connections for steam piping 2-1/2 inches and larger. Threaded connections on larger steam lines are prone to leaks under thermal expansion.

ASME B31.1 Section 119

The expansion loop is drastically undersized. The calculated thermal expansion is approximately 3.28 inches, but the loop is only designed for 1.4 inches of movement. This means the loop will be overstressed, potentially causing weld failures or equipment nozzle damage. The expansion device must be resized to handle the full calculated movement with appropriate safety factor per ASME B31.1.

ASME B31.1 Section 127.4 / AWS D10.9

Undercut exceeding 1/32 inch (0.8 mm) on any weld is a rejectable defect per ASME B31.1 and AWS D10.9. Undercut creates a stress riser that can initiate fatigue cracking under thermal cycling.

ASME B31.1 Section 137 / EJMA Standards

Expansion joints must be restrained or isolated during hydrostatic testing. Test pressure can cause unrestrained bellows to over-extend, permanently damaging the joint.

ASME B31.1 Section 137.4

This is a proper hydrostatic test per ASME B31.1. The test pressure of 1.5 times design pressure (150 × 1.5 = 225 PSI) is correct. The 10-minute hold with visual inspection of all joints meets the minimum requirements. The system passes inspection.