ASME B31.1 para. 131.4 (Table 132) / ASME BPVC Section IX

ASME B31.1 — Power Piping, para. 136.4 / Table 136.4

This is compliant. ASME B31.1 (Power Piping) does NOT mandate radiographic (RT) or ultrasonic (UT) examination for every welded joint — mandatory 100% NDE is triggered only by the thresholds in para. 136.4 / Table 136.4: butt welds and branch connections operating above 750°F, OR operating between 350°F and 750°F AND above 1025 psig AND with nominal wall thickness over 1-1/8 in. A 300 PSI (psig) steam main saturates at roughly 421°F and is far below the 1025 psig and 750°F triggers, so it does not meet any of the criteria that require RT/UT. For these service conditions B31.1 calls for visual examination of accessible weld surfaces by a qualified inspector — exactly what was performed. With welds made by a currently ASME-qualified welder and accepted by visual examination, the system meets the code-required examination and may be placed in service. (If this run were boiler external piping directly connected to the boiler, ASME Section I would govern and impose stricter rules — but the scenario describes a distribution main.)

ASME B31.1 / ASHRAE Handbook — HVAC Systems

This is a textbook-correct steam trap installation as taught at UA halls. The F&T trap is appropriate for equipment drains (it handles variable condensate loads and passes air). The strainer upstream protects the trap internals from scale and debris. The check valve downstream prevents condensate backflow from the pressurized return header. Installing the trap at the same level as the drain (no lift) ensures gravity drainage into the trap — any lift before the trap creates a water seal that impedes condensate flow.

ASME B31.1 / Steam trap selection per Armstrong/Spirax Sarco

Steam heat exchangers must have properly functioning steam traps on the condensate outlet to remove condensate and prevent water hammer. Water hammer in steam systems generates pressure shocks up to 10 times operating pressure, which can rupture piping, damage equipment, and cause severe personnel injuries.

ASME B31.1 Section 107 / MSS SP-92

This is a proper installation. Globe valves on steam service should be installed with flow entering under the disc to prevent the disc from being forced off the stem by line pressure when the valve is open. The vertical stem-up orientation is preferred for steam service to prevent condensate from pooling in the bonnet.

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.