Overview
The comprehensive governing standard for pipe hangers and supports, establishing standardized component "Type" numbers (Type 1 through Type 58), minimum material requirements, load ratings, design safety factors, selection criteria, recommended support spacing, fabrication, and field installation practices.
Scope & Applicability
Applies To Industries
Covers — materials, design, manufacture, selection, application, and installation of pipe hangers, supports, restraints, guides, anchors, and spring units across power plants, chemical plants, refineries, commercial HVAC, and industrial facilities. Consolidates former standalone standards MSS SP-69, SP-89, SP-90, and SP-127 into a single 2018 edition.
Does NOT cover (exclusions) — the following engineering aspects are governed elsewhere:
- Piping Stress Limits & Thermal Expansion: Actual support reactions, thermal movement limits, and allowable pipe stress → governed by ASME B31.1 (Power Piping) or ASME B31.3 (Process Piping).
- Primary Structural Steel Attachments: Design of main building structural steel, welded steel embeds, and concrete anchors → governed by AISC 360, AWS D1.1, and ACI 318.
- Seismic Design Demand: Dynamic building acceleration response and seismic spectrum demand → governed by ASCE 7 / IBC (SP-58 specifies hardware bracing types, not seismic building forces).
Key Requirements
MSS SP-58 establishes key minimum engineering and design rules for hanger systems:
- Standardized Component Classification: Categorizes hanger hardware into standardized "Type" numbers (e.g., Type 1 Clevis Hanger, Type 3-4 Pipe Clamps, Type 10 Beam Clamps, Type 24 U-Bolts, Type 43-46 Pipe Rollers, Type 51-53 Variable Springs, Type 54-56 Constant Springs).
- Design Safety Factors (Allowable Stress):
- Tension Rods, Clevises, & Forgings: Designed with a minimum Safety Factor of 5.0 based on ultimate tensile strength ($S_u$).
- Castings (Ductile / Malleable Iron): Designed with a minimum Safety Factor of 5.0 to 6.0.
- Structural Steel Attachments (Welded Shoes, Brackets): Designed to ASME B31.1 allowable stress limits (0.20 × $S_u$).
- Variable Spring Hanger Rules (Type 51–53): Maximum load variability between Hot Load and Cold Load must not exceed 25%:
Variability (%) = |Hot Load - Cold Load| / Hot Load × 100% ≤ 25% - Constant Support Hanger Rules (Type 54–56): Mandatory when thermal movement is large or when load variability on a variable spring would exceed 25% (maintains load deviation within ±6%).
- Maximum Support Spacing Tables: Establishes maximum recommended span limits for standard weight steel pipe under liquid (water) vs gas/steam service to control pipe sag and bending stress.
- Corrosion Protection & Galvanizing: Mandates hot-dip galvanizing (ASTM A153/A123), electro-galvanizing (ASTM B633), or specialized epoxy coatings for outdoor, marine, and corrosive chemical environments.
Technical Details
MSS SP-58 is the primary standard for pipe hangers and supports used throughout power generation, oil & gas, chemical processing, district heating, and commercial piping systems.
1. MSS SP-58 Standardized Support Component Types Matrix
| Type No. | Component Description | Primary Function / Service Application |
|---|---|---|
| Type 1 | Adjustable Clevis Hanger | Insulated or bare lines; vertical height adjustment via top nut |
| Type 3 / 4 | Heavy Duty Pipe Clamp | High load / high temperature horizontal line suspension |
| Type 8 | Extension Pipe Clamp | Vertical riser support or low-clearance horizontal clamping |
| Type 10 | C-Clamp / Beam Clamp | Structural flange attachment without field welding or drilling |
| Type 24 | Standard U-Bolt | Guide, hold-down, or anchor attachment for uninsulated pipe |
| Type 39 / 40 | Pipe Shoe (Welded / Clamped) | Insulated pipe support; elevates pipe above structure to protect insulation |
| Type 43 / 46 | Adjustable Pipe Roller / Saddle | Allows axial thermal expansion while supporting heavy pipe loads |
| Type 51 - 53 | Variable Spring Hanger | Supports thermal movement where load variability is ≤ 25% |
| Type 54 - 56 | Constant Support Hanger | Supports large thermal movement with constant lifting force (±6% load variance) |
| Type 58 | Mechanical / Hydraulic Snubber | Dynamic seismic/waterhammer restraint while permitting slow thermal movement |
2. Recommended Maximum Pipe Support Spacing (Former SP-69 Data)
Maximum recommended spacing between rigid supports for standard weight (Sch 40) steel pipe:
| Nominal Pipe Size (NPS) | Water Service Max Span (ft / m) | Steam, Gas, or Air Max Span (ft / m) | Recommended Rod Diameter (in) |
|---|---|---|---|
| 1/2" (DN 15) | 7 ft (2.1 m) | 8 ft (2.4 m) | 3/8" |
| 1" (DN 25) | 9 ft (2.7 m) | 10 ft (3.0 m) | 3/8" |
| 2" (DN 50) | 10 ft (3.0 m) | 13 ft (4.0 m) | 3/8" |
| 3" (DN 80) | 12 ft (3.7 m) | 15 ft (4.6 m) | 1/2" |
| 4" (DN 100) | 14 ft (4.3 m) | 17 ft (5.2 m) | 5/8" |
| 6" (DN 150) | 17 ft (5.2 m) | 21 ft (6.4 m) | 3/4" |
| 8" (DN 200) | 19 ft (5.8 m) | 24 ft (7.3 m) | 7/8" |
| 12" (DN 300) | 23 ft (7.0 m) | 30 ft (9.1 m) | 7/8" |
| 16" (DN 400) | 27 ft (8.2 m) | 35 ft (10.7 m) | 1" |
| 24" (DN 600) | 32 ft (9.8 m) | 42 ft (12.8 m) | 1-1/4" |
Note: Spacing limits assume straight pipe runs without concentrated valve or fitting loads. Concentrated loads require additional supports placed adjacent to valves/heavy components.
3. Historical Standards Consolidation (2018 Edition)
The 2018 edition of MSS SP-58 consolidated four legacy standalone standards:
- MSS SP-69 (Selection and Application) → Incorporated into SP-58 Chapters 4 & 5.
- MSS SP-89 (Fabrication and Installation) → Incorporated into SP-58 Chapter 6.
- MSS SP-90 (Terminology and Definitions) → Incorporated into SP-58 Chapter 2.
- MSS SP-127 (Bracing for Piping Systems) → Incorporated into SP-58 Annex B.
Engineering Notes
Crucial engineering guidance and common design/construction pitfalls for MSS SP-58 pipe hangers and supports:
1. The Travel Stop Pin Pitfall on Spring Hangers
Variable and Constant Spring Hangers are shipped from the factory with cold-setting travel stop pins (or locks) installed to lock the spring during transit and hydrostatic testing.
[!WARNING] All travel stop pins MUST be removed prior to plant thermal startup! Failure to remove travel stop pins turns spring hangers into rigid supports, causing severe over-stress, flange leakage, or nozzle damage at connected equipment.
2. Dissimilar Metal Galvanic Corrosion Barrier
Direct contact between carbon steel hanger components (clamps, U-bolts, saddles) and stainless steel or copper piping creates severe galvanic corrosion.
- Mandatory Practice: Provide dielectric isolation liners (such as neoprene pads, FRP shields, or stainless steel protective shields) or use stainless steel support components when supporting stainless steel piping.
3. Spring Hanger Selection Threshold (25% Variability Rule)
When selecting between Variable Springs (Type 51–53) and Constant Supports (Type 54–56), calculate load variability:
Variability (%) = |Hot Load - Cold Load| / Hot Load × 100%
- If Variability ≤ 25%: Use a Variable Spring Hanger.
- If Variability > 25%: A Constant Support Hanger is MANDATORY to prevent transferring excessive loads to adjacent equipment nozzles or pipe stress points.
4. Minimum Thread Engagement & Locknut Protection
Hanger rods, turnbuckles, and clevises rely on threaded connections for height adjustment and load transfer.
- Thread Engagement: Minimum thread engagement length inside nuts, turnbuckles, or clevises must be at least equal to the nominal rod diameter ($d$).
- Vibration Protection: Double nuts or approved locknuts must be installed on all hanger rods subject to pump vibration, flow pulsation, or wind loads to prevent unintended unthreading.
5. Hydrotest Weight Load Check on Spring Hangers
Piping hydrotest water weight is significantly heavier than operating gas or steam weight.
- Pre-Test Audit: Verify that spring hangers supporting steam or gas lines are pinned or backed up by temporary rigid rigging during hydrostatic testing to prevent spring overload and severe permanent deflection.
Source, Edition & Status
- Publisher
- MSS
- Edition Year
- 2018
- Industries
- Petrochemical, Power Plant, General Industry
- Last Reviewed
- 2026-07-01
- Last Updated
- 2026-07-01
- Verified By
- Engineering content reviewer
- Content Status
- reviewed
- Official Link
- msshq.org