MSS Standard Practices

MSS SP-67 / mfr

An isolation valve in a concealed/overhead service must show its position so it can be verified open or closed; the operator here has no indicator.

MSS SP-69 (recommended hanger rod diameter by pipe size)

MSS SP-69 sets a recommended minimum hanger rod diameter by pipe size, and a 6-inch pipe calls for a 3/4-inch rod. A 3/8-inch rod is rated for roughly 2-inch and smaller pipe, so it is undersized here regardless of the load math. (The actual load is about 31.5 lbs/ft × 10 ft ≈ 315 lbs per hanger, which is under a 3/8-inch rod's published safe load — but those published rod safe loads already embed the ~5:1 factor on ultimate strength, so you do not re-apply the factor; the governing requirement is the SP-69 recommended rod diameter.) The correct fix is a 3/4-inch rod, plus added margin for any valve or fitting weight.

MSS SP-69 / ASME B31.1

Hangers on insulated pipe must use insulation protection saddles or shields to prevent the hanger from crushing the insulation and creating a thermal bridge and condensation point.

MSS SP-69 / ASME B31.1 Table 121.5

Per MSS SP-69 and ASME B31.1, 1-inch steel pipe requires hanger support at maximum 7-foot intervals. The 7-foot spacing meets the code requirement exactly. The hanger type (clevis) is appropriate for horizontal insulated pipe runs.