MSS SP-69 / ASME B31.1 Table 121.5
What it means on the job
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.
Tested in 2 CraftIQ puzzles
- whats-wrongPipe Hanger Installation
- code-checkPipe Support Spacing
Related MSS sections
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.
CraftIQ explanations are original educational commentary written in trade language and verified against the cited standards. Always confirm requirements against the code edition adopted by your jurisdiction — this is training material, not a substitute for the code book or your AHJ.