MSS SP-58 — "Pipe Hangers and Supports: Materials, Design, Manufacture, Selection, Application, and Installation" — is the reference standard most projects cite when they specify pipe supports. Published by the Manufacturers Standardization Society (MSS), it defines the standard component types, their materials, allowable loads and how they should be selected and installed. If your project spec says "hangers to MSS SP-58", this guide tells you what that means in practice.
Earlier editions split selection/application rules into a companion standard, MSS SP-69; current practice consolidates these into SP-58. Projects also commonly cite ASME B31.1 (power piping) or B31.3 (process piping) alongside it — those codes govern the piping itself, while SP-58 governs the support hardware.
The standard defines dozens of numbered types. These are the ones that appear on most support schedules we quote:
| Type | Component | Typical use |
|---|---|---|
| Type 1 | Adjustable steel clevis hanger | General suspended lines, ambient to moderate temperature |
| Type 3 | Double-bolt pipe clamp | Heavier lines and higher temperatures, riser and hanger service |
| Type 8 | Extension pipe or riser clamp | Vertical pipe risers |
| Type 24 | U-bolt | Guiding and light hold-down on racks and steel |
| Type 35–38 | Pipe slides & adjustable saddles | Sliding supports; PTFE slide plates for low friction |
| Type 39/40 | Protection saddle / insulation shield | Insulated lines at sliding or clamped supports |
| Types 51–53 | Variable spring hangers & supports | Lines with moderate vertical thermal movement |
| Types 54–56 | Constant support hangers | Critical lines with large vertical movement |
Our pipe clamps and clevis hangers, U-bolts and rods, shoes, guides and anchors and spring hangers are manufactured to these type definitions, with project-spec variations fabricated to your drawings.
For variable and constant spring hangers, support drawings almost always call out an installation arrangement letter — a convention originating with the major US hanger manufacturers and used worldwide alongside SP-58 type numbers. Exact geometry varies by manufacturer's catalogue (and is confirmed on our per-tag data sheets), but the intent of each letter is consistent:
| Arr. | Mounting | Where it is used |
|---|---|---|
| A | Suspended from a single top rod (eye or threaded) | Standard overhead hanger with generous headroom |
| B / C | Suspended via top lugs or a flanged top plate bolted directly under steel | Reduced headroom below the supporting beam |
| D / E | Side lug / trunnion-mounted variants | Tight spaces where the casing must sit beside or within steelwork |
| F | Base-mounted, supporting the pipe from below via a stanchion or pipe shoe | Lines near grade or supported off racks and floors |
| G | Trapeze — a pair of units carrying a crossbar under the pipe | Large lines, or where a single central rod cannot be used |
Related reading: Variable vs constant spring hangers · Spring hanger selection guide with worked example
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