Introduction to Steel Pipe Support Systems
Proper pipe support is essential for maintaining piping system integrity. Inadequate support leads to excessive sag, increased stress at joints and connections, vibration damage, and potential system failure. This guide covers support spacing calculations, hanger types, and selection criteria based on international standards.
Maximum Support Spacing for Steel Pipes
The maximum distance between pipe supports (hangers or shoe rests) depends on pipe size, schedule, material, and the weight of the pipe plus contents. The following table provides general guidelines based on MSS SP-69 and common engineering practice:
| Pipe Size (NPS) | Schedule | Max Spacing (m) | Max Spacing (ft) |
|---|---|---|---|
| 1/2 to 1 inch | 40 | 2.0 | 6.5 |
| 1-1/4 to 2 inch | 40 | 2.5 | 8.0 |
| 2-1/2 to 3 inch | 40 | 3.0 | 10.0 |
| 4 inch | 40 | 3.5 | 11.5 |
| 6 inch | 40 | 3.8 | 12.5 |
| 8 inch | 40 | 4.0 | 13.0 |
| 10 inch | 40 | 4.3 | 14.0 |
| 12 inch | 40 | 4.5 | 15.0 |
| 16 inch | 40 | 5.0 | 16.5 |
| 20 inch | 40 | 5.5 | 18.0 |
| 24 inch | 40 | 6.0 | 19.5 |
Support Spacing Calculation Method
The maximum span between supports can be calculated using the following formula based on beam theory:
- Formula: L = sqrt(8 x f x S / w), where L = span length, f = allowable bending stress, S = section modulus, w = weight per unit length (pipe + fluid + insulation)
- Allowable deflection: Typically limited to 2.5mm or span/360, whichever is less
- Slope consideration: For gravity-drain lines, support spacing must maintain minimum slope (typically 1:100 to 1:200)
Types of Pipe Hangers and Supports
Rigid Hangers
- Clevis hanger (MSS Type 3): Most common type, U-shaped saddle supporting pipe from below. Suitable for vertical loads only
- Ring hanger (MSS Type 1): Complete ring around pipe, used for insulated pipes
- Band hanger: Flat steel strap wrapping under pipe, economical for light loads
- U-bolt hanger: Secures pipe firmly, prevents lateral movement
Spring Hangers
- Type A: Variable effort spring: Load varies with displacement. Used when thermal movement is moderate (up to 25% load variation acceptable)
- Type B: Constant effort spring: Maintains nearly constant supporting force regardless of displacement. Used for large thermal movements or critical equipment connections
- Spring sizing: Based on operating load, installed load, and vertical travel range
Guides and Anchors
- Pipe guides: Restrict lateral movement while allowing axial thermal expansion
- Pipe anchors: Fix pipe position completely. Used at equipment connections, expansion joint locations, and to divide piping into independent expansion loops
- Snubbers: Allow slow thermal movement but restrict rapid movement from seismic events, water hammer, or steam hammer
Selection Criteria for Pipe Hangers
- Load capacity: Must exceed total weight of pipe + fluid + insulation + contents (snow/ice for outdoor) with minimum 3:1 safety factor
- Temperature range: Material selection based on pipe operating temperature. Standard carbon steel up to 400 C, stainless steel for higher temperatures or corrosive environments
- Insulation consideration: Use insulated hanger saddles or pipe shields to prevent insulation compression at support points
- Corrosion protection: Hot-dip galvanized for outdoor or humid environments; stainless steel for chemical plants and marine applications
- Thermal movement: Determine if rigid, spring, or constant hanger is required based on expansion calculation
Relevant Standards
- MSS SP-58: Pipe hangers and supports – materials, design, and manufacture
- MSS SP-69: Pipe hangers and supports – selection and application
- MSS SP-89: Pipe hangers and supports – fabrication and identification
- ASME B31.1: Power piping – support requirements
- ASME B31.3: Process piping – support requirements
- EN 13480: European industrial piping – support design
Installation Best Practices
- Install hangers at locations shown on isometric drawings; field adjustments require engineering approval
- Set spring hangers to cold-load position before hydrostatic testing
- Maintain insulation continuity at support points using load-bearing insulation inserts
- Never weld hanger attachments to pressure-containing pipe – use weld pads on structural steel
- Provide drainage holes in bottom of pipe shoes for outdoor installations
- Inspect all hanger components for damage before installation
CoreMetal Steel: Pipe Support Material Supplier
CoreMetal Steel supplies carbon steel and stainless steel materials for pipe hangers and support fabrication. Our product range includes:
- Carbon steel plate and bar for clevis hangers, shoes, and base plates
- Stainless steel plate and bar for corrosive environment applications
- Hot-dip galvanized steel sheet and strip for hanger fabrication
- Spring steel wire and strip for variable and constant spring hangers
- Steel pipe for hanger rods and structural attachments
Contact CoreMetal Steel for pipe support material specifications, quantities, and delivery schedules.