+---
+title: Hangers and Supports for Mechanical Piping and Equipment
+category: Mechanical / Piping & Pumps
+toc_depth: 3
+description: >
+ When to use: Selecting, specifying, and installing hangers, supports, anchors, guides, restraints, and structural attachments for mechanical piping (steel, copper, CPVC, PEX, glass, stainless) from cryogenic up to 750 °F, 1/2 in. through 24 in. and larger, and for floor- and structure-mounted mechanical equipment (pumps, boilers, heat exchangers, fan-coil units, condensing units, packaged skids). Covers rod sizing, structural attachments, trapeze assemblies, variable- and constant-spring supports, thermal anchors and guides, and seismic bracing per ASCE 7-22 Chapter 13 / IBC 2024, for new construction and renovation on projects of all sizes.
+ Not intended for: Vibration isolation and seismic resilience mounts for rotating equipment (use [[sync/vibration-isolation-and-seismic-restraint]]); fire sprinkler hangers and sway braces governed by NFPA 13 (fire protection); HVAC ductwork supports (use [[sync/hvac-ductwork]]); insulation and insulation protection design (use [[sync/mechanical-insulation]]); pipe sizing, material selection, and pressure testing (use [[sync/hydronic-piping]]); electrical conduit and cable tray supports (use [[sync/structured-cabling]] and the electrical discipline); plumbing fixture carriers and plumbing DWV/supply hangers (plumbing discipline); and valve bodies (use [[sync/hvac-piping-valves]]).
+---
+
+# Scope {toc}
+
+## This Standard covers the materials, selection, structural attachment, and installation of hangers, supports, anchors, guides, and restraints for mechanical piping and floor- or structure-mounted mechanical equipment.
+
+## Hangers and supports support the deadweight, thermal, and seismic loads of piping and equipment and transfer those loads into the building structure through a verified load path. {note}
+
+## A support that is correctly load-rated but attached to an unverified structural element has not solved the problem — it has only moved the unknown one connection up. The governing question for every assembly is not "will the hanger hold the pipe?" but "will the complete chain from pipe to building steel hold the rated load under deadweight, thermal travel, and the design seismic event?" This Standard therefore treats the pipe attachment, the rod or member, and the structural attachment as one engineered assembly that must be designed and verified together. {note}
+
+## The hanger is the most-installed and least-inspected component in a mechanical system. A 250-foot chilled-water main may carry several hundred individual supports; a single under-rated beam clamp or a rigid hanger on a thermally active line is invisible until the pipe sags, the fitting cracks, or the AHJ red-tags the seismic bracing. Getting the spacing table, the rod size, the spring selection, and the seismic exemption check right at specification time is far cheaper than chasing field failures. {note}
+
+## Boundaries {toc}
+
+### Vibration isolation and seismic resilience mounts for rotating or reciprocating equipment — spring isolators, neoprene pads, inertia bases, and seismic snubbers — are specified in [[sync/vibration-isolation-and-seismic-restraint]], not here. {note}
+
+### Fire sprinkler piping hangers and seismic sway bracing are governed exclusively by NFPA 13 and belong to the fire protection discipline. {note}
+
+### This Standard's seismic bracing requirements shall not be applied to, or substituted for, NFPA 13 bracing.
+
+### Where a single trapeze, strut, or structural attachment supports both mechanical piping and fire sprinkler piping, that shared member is a coordinated assembly: see the Seismic Restraint section for the governing rule. {note}
+
+### HVAC ductwork supports are specified in [[sync/hvac-ductwork]]; pipe insulation and the thermal design of insulation protection saddles are specified in [[sync/mechanical-insulation]] (this Standard specifies only the support-side shield and saddle hardware at hanger points). {note}
+
+# Referenced Standards {toc}
+
+## Materials, design, fabrication, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited or a different edition is enforced by the authority having jurisdiction.
+
+## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
+
+| Standard | Title |
+|----------|-------|
+| ANSI/MSS SP-58-2025 | Pipe Hangers and Supports — Materials, Design, Manufacture, Selection, Application, and Installation |
+| MSS SP-69-2003 | Pipe Hangers and Supports — Selection and Application |
+| MSS SP-89-2003 | Pipe Hangers and Supports — Fabrication and Installation Practices |
+| MSS SP-127-2016 | Bracing for Piping Systems — Seismic, Wind, Dynamic — Design, Selection, Application |
+| ASCE/SEI 7-22 | Minimum Design Loads and Associated Criteria for Buildings and Other Structures (Chapter 13) |
+| ASME B31.1-2022 | Power Piping |
+| ASME B31.9-2017 | Building Services Piping |
+| ACI 318-19 | Building Code Requirements for Structural Concrete (Chapter 17, Anchoring to Concrete) |
+| NFPA 13-2022 | Standard for the Installation of Sprinkler Systems (boundary reference only) |
+| IBC 2024 | International Building Code (Section 1613) |
+
+## MSS SP-58 is the primary governing document; the 2025 edition is current and supersedes the 2018 edition. {note}
+
+## The 2025 edition matters for high-temperature work specifically: it revised the allowable stresses for metal framing channel and updated the temperature limits for hot-dip galvanized components. Specifications written against the 2018 edition for steam or high-temperature condensate service may carry obsolete galvanizing temperature assumptions; verify against SP-58-2025. {note}
+
+## MSS SP-69 was partially absorbed into SP-58 beginning with the 2009 edition but remains an active document and is still cited for hanger-type selection by service condition. MSS SP-127 is the companion specifically for seismic, wind, and dynamic bracing design. {note}
+
+## Nonstructural seismic design follows ASCE 7-22 Chapter 13, which IBC 2024 adopts by reference. ASCE 7-22 introduced a revised component force (Fp) formula replacing the ASCE 7-16 equation; any seismic parameter cited in project documents shall reference ASCE 7-22, not the superseded ASCE 7-16. {note}
+
+# Submittals {toc}
+
+## Action Submittals {toc}
+
+### The Contractor shall submit the following action submittals for review and approval before fabrication or installation:
+
+- Product data for each hanger, support, clamp, attachment, insert, anchor, guide, and restraint type, identified by MSS SP-58 type number, material, finish, and load rating.
+- Hanger and support schedule correlating each pipe service, material, and size to its hanger type, rod diameter, maximum spacing, and structural attachment method.
+- Spring hanger load schedule listing, for every variable- and constant-spring support, the cold load, hot load, total travel, spring rate, and load-variation percentage, indexed to the pipe stress isometric.
+- Shop drawings for fabricated supports, trapeze assemblies, pipe anchors, guides, and equipment support steel, with member sizes, weld details, and connection details.
+- Seismic bracing layout and calculations, signed and sealed by a licensed professional engineer, showing brace type, spacing, attachment, and the governing ASCE 7-22 force determination or exemption.
+- Structural attachment calculations for post-installed concrete anchors and powder-actuated fasteners, including ACI 318-19 Chapter 17 anchor design where applicable.
+
+```datasheet
+label: Action submittals required
+type: checkbox
+options:
+ - Product data (typed, rated, finished)
+ - Hanger and support schedule
+ - Spring hanger load schedule
+ - Fabrication shop drawings
+ - Seismic bracing layout and PE-sealed calculations
+ - Concrete anchor / fastener calculations
+default:
+ - Product data (typed, rated, finished)
+ - Hanger and support schedule
+ - Spring hanger load schedule
+ - Seismic bracing layout and PE-sealed calculations
+```
+
+### Spring hanger load schedules and seismic calculations shall not be deferred to the field.
+
+### Spring hanger load schedules and seismic calculations shall be submitted and approved before the associated piping is erected.
+
+## Informational Submittals {toc}
+
+### The Contractor shall submit the following informational submittals:
+
+- Manufacturer's installation instructions for proprietary inserts, anchors, beam clamps, and seismic bracing kits.
+- Welder qualification records (AWS) for any field-welded pipe attachments, anchors, or support steel.
+- Mill or material certificates for rod, channel, and structural members where a specific grade or coating is specified.
+
+```datasheet
+label: Informational submittals required
+type: checkbox
+options:
+ - Manufacturer installation instructions
+ - Welder qualifications (AWS)
+ - Material / mill certificates
+default:
+ - Manufacturer installation instructions
+ - Welder qualifications (AWS)
+```
+
+## Closeout Submittals {toc}
+
+### The Contractor shall submit the following closeout submittals:
+
+- Marked-up record drawings showing as-installed hanger, anchor, guide, and seismic brace locations.
+- Spring hanger field setting record listing the as-set cold position and travel-stop removal confirmation for each spring support.
+
+```datasheet
+label: Closeout submittals required
+type: checkbox
+options:
+ - As-installed record drawings
+ - Spring hanger field setting record
+default:
+ - As-installed record drawings
+ - Spring hanger field setting record
+```
+
+# Quality Assurance {toc}
+
+## Hanger and support components shall be the product of a manufacturer regularly engaged in their production and shall be marked or otherwise identifiable to their MSS SP-58 type and load rating. {note}
+
+### Fabrication, welding, and installation of hanger assemblies shall comply with MSS SP-89.
+
+### Field welding of pipe attachments, anchors, and support steel shall be performed by welders qualified under AWS D1.1 for structural steel or the applicable piping welding code.
+
+### Pipe attachments welded directly to pressure piping shall comply with the welding, material, and post-weld requirements of the governing piping code (ASME B31.1 or B31.9) for the service.
+
+### Seismic bracing design and the supporting calculations shall be prepared by, or under the responsible charge of, a professional engineer licensed in the project jurisdiction.
+
+### Where the authority having jurisdiction requires preapproved or listed seismic components (for example, OSHPD/HCAI special seismic certification on essential-facility projects), only components carrying the required listing shall be installed.
+
+## A note on delegated design {note}
+
+### Seismic bracing and complex spring-support layouts are commonly delegated to the Contractor's engineer; delegation transfers the calculation, not the responsibility for a coordinated result. {note}
+
+### The Engineer of Record retains responsibility for defining the design basis — Seismic Design Category, component importance factor, and the systems requiring bracing — while the delegated engineer is responsible for the means that satisfy that basis. Specifying "support as indicated" without a design basis or a required submittal is the most common way uncontrolled, uncalculated supports reach the field. {note}
+
+# Environmental and Service Conditions {toc}
+
+## Material and finish selection shall account for the installed environment, because corrosion of a structural attachment is a load-path failure, not a cosmetic defect. {note}
+
+### Hanger and support components shall be selected for the service temperature, humidity, and chemical exposure of their installed location.
+
+### Plain (uncoated) carbon steel components shall be used only in interior, conditioned, dry locations.
+
+### Components in interior wet or high-humidity locations — mechanical rooms with open sumps, below cooling-tower areas, and condensing equipment spaces — shall be hot-dip galvanized, epoxy-coated, or stainless steel.
+
+### Components in exterior, below-grade, or chemically aggressive locations shall be stainless steel or shall carry a coating system qualified for the exposure.
+
+### Dissimilar-metal contact that would promote galvanic corrosion — for example, an uncoated steel clamp in direct contact with copper tube in a wet location — shall be isolated with a dielectric barrier or avoided by material selection.
+
+```datasheet
+label: Default hanger material / finish by exposure
+type: select
+options:
+ - Plain carbon steel (interior dry only)
+ - Hot-dip galvanized (interior wet / general)
+ - Epoxy-coated carbon steel
+ - Type 304 stainless steel
+ - Type 316 stainless steel (corrosive / coastal)
+default: Hot-dip galvanized (interior wet / general)
+```
+
+## Galvanized components carry a temperature ceiling that plain steel does not. Hot-dip galvanizing can delaminate or embrittle under sustained elevated temperature; the controlling limit is defined in MSS SP-58-2025. Standard carbon-steel hangers are rated to 750 °F per MSS SP-58. {note}
+
+### The MSS SP-58-2025 temperature limit for galvanized components shall be checked before galvanized hardware is specified on steam or high-temperature condensate lines.
+
+```datasheet
+label: Service temperature range at the support
+type: select
+options:
+ - Cryogenic / below 32 °F
+ - Ambient (33 °F to 250 °F)
+ - Elevated (251 °F to 450 °F)
+ - High temperature (451 °F to 750 °F)
+default: Ambient (33 °F to 250 °F)
+unit: °F
+```
+
+# Hanger Selection and Types {toc}
+
+## Hanger type shall be selected from MSS SP-58/SP-69 by pipe material, service temperature, pipe size, and the movement the support must accommodate. The type number is not a style preference; it encodes the load mechanism, the temperature suitability, and whether the support permits or restrains pipe movement. {note}
+
+## A clevis hanger that swings freely accommodates the small axial drift of a nominally stationary line but does nothing for a pipe that grows half an inch when it heats; that pipe needs a guide, a spring, or both. Matching the type to the movement is the difference between a support and a future failure. {note}
+
+### Horizontal piping at standard ambient service shall be supported by adjustable clevis hangers (MSS Type 1) or adjustable swivel-ring hangers (MSS Type 19) unless another type is required by the service.
+
+### Small-diameter copper and CPVC piping may be supported by split-ring hangers (MSS Type 11) where the load and temperature are within the type's rating.
+
+### Vertical piping (risers) shall be supported at each floor by riser clamps (MSS Type 8) bearing on the structure at the floor penetration.
+
+### Grouped parallel pipe runs may be supported on trapeze assemblies in lieu of individual hangers where the combined load, including liquid fill and any future-pipe allowance, is within the trapeze rating.
+
+### Thermally active piping with calculated displacement at the support exceeding 1/2 in. shall be supported by spring hangers as required by the Spring Supports section, not by rigid rod hangers.
+
+```datasheet
+label: Primary horizontal hanger type
+type: select
+options:
+ - Adjustable clevis (MSS Type 1)
+ - Adjustable swivel ring (MSS Type 19)
+ - Split ring (MSS Type 11)
+ - Trapeze (channel on two rods)
+default: Adjustable clevis (MSS Type 1)
+```
+
+```datasheet
+label: Individual hangers vs. trapeze for grouped runs
+type: radio
+options:
+ - Individual hangers per pipe
+ - Trapeze for grouped parallel runs
+default: Individual hangers per pipe
+```
+
+## Pipe contact and protection {toc}
+
+### Hangers in contact with copper tube shall be copper-plated, plastic-coated, or otherwise isolated to prevent galvanic action, or the tube shall be isolated from a steel hanger by a non-metallic barrier.
+
+### At each support on insulated piping, an insulation protection shield or pipe saddle shall be provided so that the support load bears on the shield, not on crushed insulation, and the vapor barrier is maintained continuously through the support. (Insulation thermal design is specified in [[sync/mechanical-insulation]].)
+
+### Insulation protection shields shall be a minimum of 2 times the pipe outside diameter in length, or 12 in., whichever is greater.
+
+### Saddle and shield insert material shall suit the service temperature: high-density rigid insert (for example calcium silicate) for service above 250 °F, and high-density polyurethane or equivalent for lower-temperature service.
+
+## Omitting protection shields on insulated lines is one of the most common and most damaging specification errors. Without a shield, the hanger crushes the insulation at every support, creating a thermal bridge and a cold spot where moisture condenses; on chilled-water and refrigerant lines this drips, corrodes, and eventually rots the insulation along the entire run. The shield is not optional hardware — it is part of the support. {note}
+
+```datasheet
+label: Insulation protection at hanger points
+type: radio
+options:
+ - Protection shield (uninsulated pipe — none required)
+ - Steel protection shield over insulation
+ - Pipe saddle with rigid insulation insert
+ - 360-degree insulated support with load-bearing insert
+default: Steel protection shield over insulation
+```
+
+```datasheet
+label: Protection shield minimum length
+type: select
+options:
+ - 12 in. minimum
+ - 2 x pipe OD
+ - 2 x pipe OD or 12 in., whichever is greater
+default: 2 x pipe OD or 12 in., whichever is greater
+```
+
+# Hanger Rod Sizing {toc}
+
+## Hanger rod is sized to the rated load with a generous safety factor; the default rod diameters below follow MSS SP-58 Table 1 and ASME B31.9 and represent the 80% case for single-rod hangers on water-filled metallic pipe. {note}
+
+### Larger rods shall be used where multiple pipes share a rod (trapeze) or where the load exceeds the single-pipe assumption.
+
+### Hanger rod shall be continuous-thread or machine-thread rod sized for the supported load and shall not be less than the minimum diameter for the pipe size below.
+
+### Rod material and finish shall match the hanger material/finish selected for the exposure (plain, galvanized, or stainless).
+
+### Trapeze and multi-pipe assemblies shall have rod sized for the total assembly load — combined pipe weight, liquid fill, insulation, and any specified future-pipe allowance — not for a single pipe.
+
+| Pipe size | Minimum rod diameter |
+|-----------|----------------------|
+| 1/2 in. through 1-1/4 in. | 3/8 in. |
+| 1-1/2 in. and 2 in. | 1/2 in. |
+| 2-1/2 in. and 3 in. | 5/8 in. |
+| 4 in. | 3/4 in. |
+| 6 in. | 1 in. |
+| 8 in. through 12 in. | 1-1/4 in. |
+
+```datasheet
+label: Hanger rod minimum diameter (single-rod, per pipe size)
+type: select
+options:
+ - 3/8 in. (pipe through 1-1/4 in.)
+ - 1/2 in. (1-1/2 in. and 2 in.)
+ - 5/8 in. (2-1/2 in. and 3 in.)
+ - 3/4 in. (4 in.)
+ - 1 in. (6 in.)
+ - 1-1/4 in. (8 in. to 12 in.)
+default: 1/2 in. (1-1/2 in. and 2 in.)
+```
+
+```datasheet
+label: Hanger rod material / finish
+type: select
+options:
+ - Plain carbon steel
+ - Hot-dip galvanized
+ - Type 304 stainless steel
+ - Type 316 stainless steel
+default: Hot-dip galvanized
+```
+
+# Hanger Spacing {toc}
+
+## Support spacing depends on pipe material, diameter, and the weight of the fluid, and each material/fluid combination has its own span table. Applying a steel-pipe span to plastic pipe, or a gas-filled span to a water-filled line, is a direct route to sag, pooling, and overstressed fittings. {note}
+
+## The most common spacing error is borrowing a single table. Steel pipe carrying water spans far more than the same steel pipe carrying steam-weight gas would suggest is conservative, while CPVC spans a fraction of steel and loses span as it warms. Select the span from the table that matches both the material and the contents. {note}
+
+### Horizontal steel pipe shall be supported at intervals not exceeding the values of ASME B31.9 Table 922.1.2 for the pipe size and service; liquid-filled lines shall use the reduced (water-filled) spacing.
+
+### Horizontal copper tube shall be supported at intervals not exceeding the MSS SP-69 values for the tube size.
+
+### Horizontal CPVC and other thermoplastic pipe shall be supported at the manufacturer's published intervals for the service temperature, which decrease as temperature rises; the values below apply at approximately 73 °F.
+
+### A hanger shall be installed within 12 in. of each fitting, valve, branch connection, and change of direction, and at each concentrated load, so that no fitting is left on an unsupported cantilever.
+
+### Vertical piping shall be supported at each floor and at intervals not exceeding the code maximum for the pipe material.
+
+| Steel pipe size | Max spacing (water service) |
+|-----------------|------------------------------|
+| 1 in. | 7 ft |
+| 2 in. | 10 ft |
+| 4 in. | 14 ft |
+| 6 in. | 17 ft |
+| 8 in. | 19 ft |
+| 12 in. | 23 ft |
+
+| Copper tube size | Max spacing (horizontal) |
+|------------------|---------------------------|
+| 3/4 in. through 1 in. | 5 ft |
+| 1-1/4 in. through 2 in. | 6 ft |
+| 2-1/2 in. through 3 in. | 8 ft |
+| 4 in. | 10 ft |
+
+| CPVC size (at ~73 °F) | Max spacing |
+|------------------------|-------------|
+| 1 in. and smaller | 3 ft |
+| 1-1/4 in. through 2 in. | 4 ft |
+
+```datasheet
+label: Pipe material governing the spacing table
+type: select
+options:
+ - Steel (ASME B31.9 Table 922.1.2)
+ - Copper tube (MSS SP-69)
+ - CPVC / thermoplastic (manufacturer, temp-derated)
+ - Stainless steel
+default: Steel (ASME B31.9 Table 922.1.2)
+```
+
+```datasheet
+label: Apply water-filled (liquid) spacing reduction
+type: radio
+options:
+ - Yes — liquid-filled line, use reduced spacing
+ - No — gas / vapor service
+default: Yes — liquid-filled line, use reduced spacing
+```
+
+```datasheet
+label: Maximum support distance from each fitting / change of direction
+type: range
+min: 6
+max: 18
+step: 3
+unit: in.
+default: 12
+```
+
+# Structural Attachments {toc}
+
+## The structural attachment is where the load enters the building, and it is the connection most often left to field judgment. Every attachment method has a correct application and a way to be wrong: a beam clamp on a flange too thick to grip, a wedge anchor in a seismic zone that the AHJ will reject, a powder-actuated pin into the bottom of a hollow deck flute. The attachment shall be selected for the actual structural element and the actual load, not for installer convenience. {note}
+
+### The structural attachment for each support shall be selected for the structural element it engages — cast-in insert, post-installed anchor, top- or bottom-flange beam clamp, channel/strut attachment, or powder-actuated fastener — and for the rated load.
+
+### Beam clamps shall be selected and verified for the flange thickness and width of the actual member; a clamp that cannot be fully tightened on the installed flange shall not be used.
+
+### Post-installed concrete anchors shall be designed in accordance with ACI 318-19 Chapter 17 (strength design) for the applied tension and shear, including the seismic ductility provisions of ACI 318-19 Section 17.10 where the Seismic Design Category requires them.
+
+### Powder-actuated fasteners shall be used only where listed for the base material and load, shall not be used in tension into the underside of steel deck flutes, and shall not be used for seismic brace anchorage unless specifically listed for that use.
+
+### Cast-in concrete inserts, where used, shall be set before the pour at coordinated locations and shall be rated for the support load.
+
+### Hanger and attachment locations shall be coordinated with the structural framing, slab penetrations, deck rib orientation, applied fireproofing, and other trades before installation.
+
+## On seismic ductility {note}
+
+### In Seismic Design Category C and above, authorities having jurisdiction routinely reject standard expansion (wedge) anchors used for piping and equipment restraint unless the anchor is qualified for cracked-concrete seismic service and designed per ACI 318-19 Chapter 17. Specifying "expansion anchor" without that qualification invites a field rejection and rework. {note}
+
+### Anchor design for components assigned a component importance factor of 1.5 (Ip = 1.5) shall additionally satisfy the ductility and overstrength requirements that apply to those components under ACI 318-19 and ASCE 7-22.
+
+```datasheet
+label: Structural attachment to concrete
+type: select
+options:
+ - Cast-in (preset) insert
+ - Post-installed wedge anchor (seismic-qualified)
+ - Post-installed undercut anchor
+ - Adhesive (bonded) anchor
+default: Post-installed wedge anchor (seismic-qualified)
+```
+
+```datasheet
+label: Structural attachment to steel framing
+type: select
+options:
+ - Top-flange beam clamp (MSS Type 25/28)
+ - Bottom-flange C-clamp (MSS Type 19/23)
+ - Welded attachment (qualified welder)
+ - Beam clamp with retaining strap
+default: Top-flange beam clamp (MSS Type 25/28)
+```
+
+```datasheet
+label: Concrete anchor design basis
+type: radio
+options:
+ - ACI 318-19 Ch. 17, non-seismic
+ - ACI 318-19 Ch. 17, seismic (SDC C+)
+default: ACI 318-19 Ch. 17, seismic (SDC C+)
+```
+
+```datasheet
+label: Metal framing channel (strut) size for trapeze / equipment supports
+type: select
+options:
+ - 1-5/8 in. x 1-5/8 in., 14 ga
+ - 1-5/8 in. x 1-5/8 in., 12 ga
+ - 1-5/8 in. x 3-1/4 in. (double), 12 ga
+ - Back-to-back double channel
+default: 1-5/8 in. x 1-5/8 in., 12 ga
+```
+
+# Thermal Anchors and Guides {toc}
+
+## A pipe that changes temperature changes length, and that movement has to go somewhere. Left uncontrolled, thermal growth concentrates at the weakest fitting and eventually fails it. Anchors and guides control where the movement goes: an anchor fixes a point so the pipe grows away from it in a known direction, and a guide lets the pipe slide axially through it while restraining it laterally so it does not buckle or whip. Together they convert uncontrolled growth into a designed expansion pattern. {note}
+
+## Anchor and guide layout is engineering, not field discretion. The locations follow from a thermal expansion analysis of the run — the operating temperature range, the coefficient of expansion, the anchor-to-anchor lengths, and the expansion device or loop that absorbs the growth. Delegating the layout to the installer without that analysis produces pipe that moves in unintended directions and fittings that crack. {note}
+
+### Pipe anchors shall be located to divide thermally active runs into controlled lengths and to direct thermal growth toward expansion loops, expansion joints, or designated flexible offsets.
+
+### Pipe guides shall be located adjacent to expansion devices and along guided runs to permit axial movement while restraining lateral movement and preventing buckling, in accordance with the expansion device manufacturer's guide-spacing requirements.
+
+### Anchors shall be designed and detailed to transfer the anchor force into the building structure; an anchor force shall not be carried by an ordinary hanger.
+
+### Where the expansion analysis is performed by a delegated engineer, the anchor and guide layout, forces, and movements shall be submitted for review before fabrication.
+
+### Low-friction slide plates (for example PTFE- or graphite-faced) shall be provided at guides and supports of high-temperature lines where the support must accommodate axial sliding without imposing friction loads that overstress the structure.
+
+```datasheet
+label: Thermal expansion management approach
+type: select
+options:
+ - Expansion loops with anchors and guides
+ - Axial expansion joints with anchors and guides
+ - Flexible pipe offsets (inherent flexibility)
+ - Expansion compensators
+default: Expansion loops with anchors and guides
+```
+
+```datasheet
+label: Guide type at thermally active runs
+type: radio
+options:
+ - Pipe guide (MSS Type 35), spider/sleeve
+ - Strut-mounted roller guide
+ - Slide plate with lateral restraint
+default: Pipe guide (MSS Type 35), spider/sleeve
+```
+
+### The locations of anchors, guides, and expansion devices for each thermally active run shall be shown on the drawings: [[drawing: thermal anchor and guide layout]].
+
+# Spring Supports {toc}
+
+## When a pipe moves vertically as it heats, a rigid hanger cannot follow it. At the cold position the rigid hanger may be overloaded; at the hot position the pipe lifts off it and sags between supports, throwing its weight onto adjacent hangers and fittings. A spring support follows the vertical travel while continuing to carry the load, which is why thermally active piping needs springs, not rods. {note}
+
+## There are two kinds of spring support, and the difference is the load they deliver through the travel. A variable-spring hanger uses a coil spring, so the supporting force changes as the spring compresses and extends — acceptable when the load change across the travel is small. A constant-effort support uses a linkage that delivers a nearly constant force over its entire travel — required where the displacement is large or where even a modest load change would overstress the pipe, as on high-temperature mains and at connections to sensitive equipment. {note}
+
+### Variable-spring hangers shall be selected so that the load change between the cold and hot positions does not exceed 25% of the operating (hot) load.
+
+### Where the calculated vertical displacement or the load-variation limit cannot be met by a variable-spring hanger, a constant-effort (constant-spring) support shall be provided.
+
+### Each spring support shall be selected from the pipe stress isometric for its cold load, hot load, and total travel, and shall be sized so the operating position falls within the working range of the spring with travel margin above and below.
+
+### Each spring support shall be furnished with a travel indicator and with travel stops that hold the spring at its cold-set position during erection and hydrostatic test.
+
+### Travel stops shall be removed after the system is filled and before the pipe is placed in thermal service, and stop removal shall be recorded for each support.
+
+### Spring supports at connections to rotating equipment shall be selected so that the residual load and load variation do not impose unacceptable nozzle loads on the equipment.
+
+## Spring supports left with their travel stops in place are a classic commissioning failure: the stop turns a spring into a rigid hanger, defeating the entire reason it was specified. Stop removal is a verifiable closeout item, which is why this Standard requires it to be recorded per support. See [[sync/commissioning]] for system turnover verification. {note}
+
+```datasheet
+label: Spring support type for thermally active piping
+type: radio
+options:
+ - Rigid hanger (no significant vertical travel)
+ - Variable-spring hanger (load variation <= 25%)
+ - Constant-effort support (large travel / sensitive load)
+default: Variable-spring hanger (load variation <= 25%)
+```
+
+```datasheet
+label: Variable-spring maximum load variation
+type: range
+min: 10
+max: 25
+step: 5
+unit: "%"
+default: 25
+```
+
+```datasheet
+label: Spring support accessories
+type: checkbox
+options:
+ - Travel indicator / scale
+ - Erection / hydrotest travel stops
+ - Load-variation nameplate
+ - Cold-set load preset at factory
+default:
+ - Travel indicator / scale
+ - Erection / hydrotest travel stops
+ - Cold-set load preset at factory
+```
+
+## The cold-load and hot-load value at each spring support follows from the pipe stress analysis and shall be scheduled per support: [[drawing: spring hanger load schedule]].
+
+# Seismic Restraint {toc}
+
+## In moderate and high seismic regions, piping and equipment must be braced so they do not swing, fall, or tear loose during an earthquake and become a hazard or a continuity-of-operation failure. The governing requirements are in ASCE 7-22 Chapter 13, adopted by IBC 2024; Section 13.6 addresses mechanical and electrical components specifically. The bracing system that resists this lateral load is engineered and is distinct from the deadweight hangers above. {note}
+
+## ASCE 7-22 provides a meaningful exemption, and applying it correctly avoids bracing piping that does not need it. Under Section 13.1.4, a component is exempt from seismic design where it weighs no more than 400 lb and its center of mass is no more than 4 ft above the floor (with the further trade-size and distribution-system allowances in that section). The exemption is checked against the as-built condition, not assumed. {note}
+
+### The need for seismic bracing shall be determined from the project Seismic Design Category, the applicable ASCE 7-22 Section 13.1.4 exemptions, and the trade size of the piping, before bracing is laid out.
+
+### Piping requiring seismic restraint shall be braced with listed or engineered lateral and longitudinal sway braces designed for the ASCE 7-22 component force (Fp) for the system.
+
+### Lateral sway braces for piping 2-1/2 in. and larger shall be spaced at not more than 40 ft on center, and longitudinal braces at not more than 80 ft on center, unless a project-specific analysis establishes a different spacing.
+
+### Seismic braces shall attach to the structure through connections designed for the brace force, and brace anchorage to concrete shall satisfy the ACI 318-19 Chapter 17 seismic anchor provisions.
+
+### Components and distribution systems designated with a component importance factor of 1.5 (Ip = 1.5) shall be braced and anchored to remain operable or position-retained as required by ASCE 7-22 for that designation.
+
+### Seismic bracing for mechanical piping shall be designed and detailed independently from NFPA 13 fire sprinkler sway bracing; mechanical braces shall not be substituted for, nor counted as, sprinkler bracing.
+
+## The shared-member rule {note}
+
+### Where a single trapeze, strut, or structural attachment supports both mechanical piping and fire sprinkler piping, the entire shared assembly shall be designed under ASCE 7-22 with the component importance factor of the most critical system it carries (Ip = 1.5 where it carries sprinkler piping).
+
+### The design of a shared trapeze or structural attachment supporting both mechanical and fire sprinkler piping shall be coordinated between the mechanical and fire protection engineers.
+
+### NFPA 13 fire sprinkler hangers and sway braces are governed solely by NFPA 13; nothing in this Standard modifies those requirements except to require coordination on shared structures. {note}
+
+```datasheet
+label: Seismic Design Category (project)
+type: select
+options:
+ - SDC A or B (no bracing required)
+ - SDC C
+ - SDC D
+ - SDC E or F
+default: SDC D
+```
+
+```datasheet
+label: ASCE 7-22 Section 13.1.4 exemption applies
+type: radio
+options:
+ - "Yes — <= 400 lb and CG <= 4 ft, exempt"
+ - No — seismic bracing required
+default: No — seismic bracing required
+```
+
+```datasheet
+label: Lateral sway brace maximum spacing
+type: range
+min: 20
+max: 40
+step: 5
+unit: ft
+default: 40
+```
+
+```datasheet
+label: Longitudinal sway brace maximum spacing
+type: range
+min: 40
+max: 80
+step: 10
+unit: ft
+default: 80
+```
+
+```datasheet
+label: Component importance factor (Ip)
+type: radio
+options:
+ - "1.0 — standard component"
+ - "1.5 — life-safety / operability / Ip-designated"
+default: "1.0 — standard component"
+```
+
+### Seismic brace locations and the bracing layout for each braced run shall be shown on the seismic bracing drawings: [[drawing: seismic bracing layout]].
+
+# Equipment Support and Anchorage {toc}
+
+## Floor- and structure-mounted mechanical equipment is supported and anchored to carry its operating weight and to resist the seismic forces that would otherwise slide or overturn it. The anchorage is engineered to a bolt pattern and an anchor design, not chosen by available holes in a housing. Where the equipment is vibration-isolated, the anchorage works through or around the isolation system, which is specified in [[sync/vibration-isolation-and-seismic-restraint]]. {note}
+
+### Floor-mounted equipment shall be set on a housekeeping pad or structural base and anchored through the manufacturer's bolt pattern to anchors designed for the equipment operating weight and seismic force.
+
+### Equipment anchorage to concrete shall be designed per ACI 318-19 Chapter 17, including the seismic provisions where the Seismic Design Category requires them.
+
+### Base plates, grout, and where required shear lugs shall be detailed to transfer equipment shear and overturning into the supporting structure.
+
+### Equipment requiring vibration isolation shall be anchored through isolation mounts or seismically rated isolators selected under [[sync/vibration-isolation-and-seismic-restraint]]; the anchorage and the isolation shall be coordinated as one assembly.
+
+### Suspended equipment (for example fan-coil units and small terminal units) shall be supported from the structure by hangers and attachments rated for the unit operating weight and braced for seismic force where required by ASCE 7-22.
+
+```datasheet
+label: Equipment mounting method
+type: select
+options:
+ - Floor mount on housekeeping pad, hard-anchored
+ - Floor mount on vibration isolators
+ - Suspended from structure (rod hangers)
+ - Structural steel support frame
+default: Floor mount on housekeeping pad, hard-anchored
+```
+
+```datasheet
+label: Housekeeping pad height
+type: range
+min: 3.5
+max: 6
+step: 0.5
+unit: in.
+default: 4
+```
+
+```datasheet
+label: Equipment seismic anchorage required
+type: radio
+options:
+ - Yes — designed per ASCE 7-22 / ACI 318-19 Ch. 17
+ - "No — within ASCE 7-22 13.1.4 exemption"
+default: Yes — designed per ASCE 7-22 / ACI 318-19 Ch. 17
+```
+
+# Installation {toc}
+
+## Hangers and supports shall be installed so the completed system hangs level, drains as designed, and presents a verified load path at every support. The execution rules below close the gap between a correct schedule and a correct field result. {note}
+
+### Hangers and supports shall be installed in accordance with MSS SP-89 and the approved hanger and support schedule.
+
+### Hanger rods shall hang vertically (plumb) at the operating position; rods shall not be installed at an angle to make up for a missed layout, and shall not be bent or kinked.
+
+### Hangers shall be adjusted so that horizontal piping maintains the slope and drainage indicated and so that the load is distributed across the supports as designed, with no support carrying a grossly disproportionate share.
+
+### Trapeze and strut members shall be cut square, with cut ends deburred and field-cut surfaces of coated members touched up to restore the coating.
+
+### Supports, anchors, and guides shall be installed clear of pipe insulation thickness so that insulation and its vapor barrier pass continuously through the support, using protection shields or saddles as specified.
+
+### Powder-actuated and post-installed anchors shall be installed per the manufacturer's listing, with the specified embedment, edge distance, and spacing, and shall not be installed in cracked or spalled concrete outside the anchor's qualification.
+
+### Field welds on pipe attachments and support steel shall be made by qualified welders, and welds on coated members shall be cleaned and recoated.
+
+### Where temporary supports are used during construction, they shall be removed and replaced with the permanent supports before the system is placed in service.
+
+### Spring support travel stops shall remain in place through hydrostatic testing and shall be removed before the system is placed in thermal service, with removal recorded per support.
+
+# Field Quality Control {toc}
+
+## Installed supports shall be verified before the system is concealed or placed in service, because a missed under-rated attachment is far cheaper to find on a walkdown than after a failure. {note}
+
+### The Contractor shall verify, and make available for the Engineer's observation, that hanger types, rod sizes, spacing, and attachments match the approved schedule.
+
+### Spring support cold settings shall be confirmed against the load schedule, and travel-stop removal shall be confirmed and recorded before thermal startup.
+
+### Seismic braces and equipment anchorage shall be available for inspection by the authority having jurisdiction where the AHJ requires special inspection of seismic components.
+
+### Post-installed anchors shall be installed and, where required by the specification or the AHJ, proof-load tested to the specified value.
+
+```datasheet
+label: Field verification scope
+type: checkbox
+options:
+ - Type / rod / spacing audit vs. schedule
+ - Spring cold-setting and stop-removal record
+ - Seismic special inspection (AHJ)
+ - Post-installed anchor proof-load test
+default:
+ - Type / rod / spacing audit vs. schedule
+ - Spring cold-setting and stop-removal record
+```
+
+# Delivery, Storage, and Handling {toc}
+
+## Hanger and support components shall be delivered in the manufacturer's packaging, identified by type and rating, and stored off the ground and protected from weather and corrosion until installation.
+
+## Spring supports shall be handled with their travel stops engaged and shall not be released or repositioned until installed and ready for setting.
+
+## Coated and stainless components shall be protected from contact with carbon steel and from weld spatter during storage and handling to preserve their corrosion resistance.
+
+# Warranty {toc}
+
+## Hanger, support, anchor, guide, and restraint components shall be warranted against defects in materials and workmanship for the period required by the Contract, but not less than one year from Substantial Completion.
+
+## Spring and constant-effort supports shall be warranted to perform within their rated load and travel for the warranty period.
+
+```datasheet
+label: Warranty period
+type: select
+options:
+ - 1 year from Substantial Completion
+ - 2 years from Substantial Completion
+ - 5 years on spring/constant supports
+default: 1 year from Substantial Completion
+```
+
+# Spare Parts {toc}
+
+## The Contractor shall furnish any project-specific spare parts required by the Contract, such as replacement spring cartridges or travel indicators for specialty supports.
+
+```datasheet
+label: Spare parts to furnish
+type: checkbox
+options:
+ - Spare spring cartridges (specialty supports)
+ - Spare travel indicators
+ - Spare beam clamps / attachments (typical sizes)
+ - None required
+default:
+ - None required
+```