ASME BPVC Section I PG-71.2

ASME Boiler and Pressure Vessel Code, Section IV — HG-400

ASME BPVC Section IV requires that safety relief valves on hot water boilers be set at or below the maximum allowable working pressure (MAWP), never above it. A valve set at 157.5 psig on a 150 psig rated boiler allows the vessel to be pressurized beyond its design limit before the valve lifts. This defeats the purpose of the safety valve, which is to prevent overpressurization at or before the rated limit. The valve must be replaced with one stamped at 150 psig or lower. This is a mandatory violation that will fail jurisdictional inspection, and the boiler must be taken out of service until corrected.

ASME BPVC Section I PG-71 / ASME B31.1

ASME BPVC Section I and ASME B31.1 require PRV discharge to be piped to a safe location where released steam cannot endanger personnel. Discharge into an occupied walkway creates severe burn and scalding hazards. PRV outlets must be directed vertically upward or to a safe discharge point away from personnel areas.

ASME BPVC Section I PG-71 / ASME B31.1 Section 122.6

This fails code on multiple counts. First, ASME Section I PG-71.4 prohibits reducing the discharge pipe below the area of the PRV outlet — the 2-inch to 1.5-inch reduction restricts flow and creates excessive back pressure on the PRV, reducing its relieving capacity. Second, the discharge termination at 4 feet above ground level creates a scalding hazard to personnel in the equipment yard; discharge must be directed to a safe location where personnel cannot be exposed to the steam release. Third, the horizontal discharge piping without a drain will accumulate condensate, which can cause water hammer when the PRV lifts. PRV discharge piping must be self-draining with a drip pan elbow or weep hole at the low point per ASME B31.1 Section 122.6.

ASME BPVC Section IV / ASME B31.1

This fails code. ASME Boiler and Pressure Vessel Code Section IV (Heating Boilers) and ASME B31.1 require a safety relief valve on the low-pressure side of every pressure reducing valve station. The safety valve must be set at or below the MAWP of the downstream equipment (30 PSI in this case). If the PRV fails open, full upstream pressure (150 PSI) would reach equipment rated for only 30 PSI — a catastrophic overpressure event. This is one of the most critical safety lessons taught at every UA local.

ASME BPVC Section IX / ASME B31.1

Per ASME Section IX, a welder qualified on 6-inch pipe is qualified for pipe diameters from 2-7/8 inches and larger (for pipe over 2-7/8" OD test coupons). The 4-inch pipe falls within this range. Since the WPS covers both sizes and the same welding processes are used, this is code-compliant.

ASME BPVC Section VIII / OSHA 1910.169

This passes code requirements. The tank has proper ASME Section VIII certification with National Board registration as required by OSHA 1910.169. The PRV is correctly set at the MAWP of 200 psig, satisfying ASME Section VIII UG-134 which requires the relief device to be set at or below the MAWP. The automatic condensate drain and pressure gauge are operational requirements for reliable compressed air service. The annual external inspection meets the minimum inspection frequency required by most jurisdictional authorities. Note that internal inspections may also be required at intervals determined by the jurisdiction and the tank's corrosion history.