Minimum Hanger Rod Diameter from Load (MSS SP-58)
The smallest threaded rod whose MSS SP-58 safe load clears the per-hanger load.
Example
You enter
- Operating load per hanger (lb) 228
- Temperature derate factor (1.0 at ambient) 1
You get
- Minimum rod diameter 3/8
- Utilization (%) 31.2
Checked against published worked examples from: National Pipe Hanger Corp. (per MSS SP-58).
Details, formula, and sources
ScopeThe smallest carbon-steel threaded rod whose MSS SP-58 maximum safe load (at or below 650F) clears the per-hanger load after the temperature derate, with the utilization (228 lb -> 3/8 in at 31%). The single lookup that decides the rod stock on the truck. Above 650F apply the standard's derate; the engineer of record and the standard's current edition govern the final selection.
Formula or tablerated(d) = MSS_SP58_table[d] x temp_derate; required_rod = smallest d such that rated(d) >= load_lb; utilization = load_lb / rated(required_rod) x 100. Table: 3/8 in 730 | 1/2 in 1350 | 5/8 in 2160 | 3/4 in 3230 | 7/8 in 4480 | 1 in 5900 | 1-1/8 in 7420 | 1-1/4 in 9500 | 1-3/8 in 11290 | 1-1/2 in 13800 lb.
Source and editionMSS SP-58 carbon-steel threaded-rod maximum safe loads (at or below 650F), by name; the rod-selection logic is first-principles. The values are the current MSS SP-58 basis (50,000 psi ultimate / 3.5, less 25% = 10,700 psi on the B1.1 root area) as National Pipe Hanger Fig. 755 (2025) and Anvil Fig. 146 publish them.
Free accessThe maximum safe loads are the MSS SP-58 carbon-steel threaded-rod values, as published in current hanger catalogs (National Pipe Hanger, Anvil); the selection is a simple table lookup.
What governsEstimate. AHJ and licensed professional govern.
API field namesload_lb, temp_derate, rod_dia, utilization_pct
- Rod loads MSS SP-58 carbon-steel threaded-rod maximum safe loads at or below 650FMSS SP-58
- Temperature derate above 650F apply the standard's derate curve; the default 1.0 is the at-ambient valueMSS SP-58
- Exceeds table a load above the largest tabulated rod (1-1/2 in) after derate returns an engineer-the-support errorMSS SP-58