1 Scope

NOTE This standard covers the materials, selection, and installation of vibration isolation and seismic restraint for mechanical, electrical, and plumbing equipment and for the piping, ductwork, and conduit distribution systems that connect to it. (1.1)

NOTE Two linked but distinct subjects are addressed: vibration isolation, which keeps equipment-generated vibration out of the building structure, and seismic restraint, which keeps equipment and distribution systems in place during an earthquake. (1.2)

NOTE The boundary of work under this standard is the isolation and restraint hardware and its attachment to both the equipment and the building structure; the supported equipment and the distribution systems themselves are governed by their respective standards. (1.4)

NOTE A vibration isolation or seismic restraint deficiency is rarely discovered at installation; it appears later as transmitted noise and vibration complaints in occupied spaces, as a failed special inspection, or as catastrophic displacement of equipment and ruptured piping during a seismic event. (1.5)

1.6 Seismic Coordination with the Structural Engineer of Record

1.6.1 The seismic design forces, the attachment loads delivered to the structure, and the adequacy of the supporting structure to receive those loads shall be coordinated with the structural engineer of record (SEOR).

NOTE This standard governs the isolation and restraint of the nonstructural components; it does not govern the design of the building structure or its seismic-force-resisting system. (1.6.2)

1.6.3 Attachment forces computed under ASCE/SEI 7 Chapter 13 shall be transmitted to the SEOR for confirmation that the structure can receive them at each attachment location.

1.7 Coordination with Other Standards

1.7.1 Equipment selection, weights, and operating speeds shall be obtained from the equipment standards and schedules, including HVAC FansHVAC FansResolves to the current edition.sync/hvac-fans and HVAC PumpsHVAC PumpsResolves to the current edition.sync/hvac-pumps.

1.7.2 Housekeeping pad dimensions, reinforcement, and embedded anchorage shall be coordinated with Concrete PadsConcrete Equipment PadsResolves to the current edition.sync/concrete-pads.

1.7.3 Pipe and duct gravity supports and the seismic bracing of piping and ductwork shall be coordinated with Hydronic PipingHydronic PipingResolves to the current edition.sync/hydronic-piping and HVAC DuctworkHVAC DuctworkResolves to the current edition.sync/hvac-ductwork.

1.7.4 Raceway and conduit support and bracing shall be coordinated with Raceways And ConduitRaceways and ConduitResolves to the current edition.sync/raceways-and-conduit.

2 Referenced Standards

2.1 Equipment, materials, and installation shall comply with the latest adopted edition of each standard below unless a specific edition is referenced by the contract documents or by the local building code.

2.2 Where conflicts exist between referenced standards, the more stringent requirement shall govern unless the structural engineer of record directs otherwise in writing.

2.3 Referenced standards list

Standard	Title
ASCE/SEI 7	Minimum Design Loads and Associated Criteria for Buildings and Other Structures (Chapter 13, Seismic Design Requirements for Nonstructural Components)
IBC	International Building Code (Chapter 16 structural design; Chapter 17 special inspections and tests)
ACI 318	Building Code Requirements for Structural Concrete (Chapter 17, Anchoring to Concrete)
ACI 355.2	Qualification of Post-Installed Mechanical Anchors in Concrete
ACI 355.4	Qualification of Post-Installed Adhesive Anchors in Concrete
ICC-ES AC156	Acceptance Criteria for Seismic Qualification by Shake-Table Testing of Nonstructural Components
ICC-ES AC193	Acceptance Criteria for Mechanical Anchors in Concrete Elements
ICC-ES AC308	Acceptance Criteria for Post-Installed Adhesive Anchors in Concrete Elements
SMACNA	Seismic Restraint Manual: Guidelines for Mechanical Systems (4th Edition)
ASHRAE Handbook	HVAC Applications, Chapter 49 (Noise and Vibration Control)
ANSI/ASHRAE 171	Method of Testing Seismic Restraint Devices for HVAC&R Equipment
MSS SP-58	Pipe Hangers and Supports — Materials, Design, Manufacture, Selection, Application, and Installation
ASTM A36	Standard Specification for Carbon Structural Steel
ASTM A123	Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products
ASTM A1011	Standard Specification for Steel, Sheet and Strip, Hot-Rolled, Carbon, Structural
ASTM D2240	Standard Test Method for Rubber Property — Durometer Hardness
NFPA 13	Standard for the Installation of Sprinkler Systems (sprinkler-pipe seismic bracing, where it governs)
MIL-spec / aircraft cable	Galvanized aircraft cable for cable seismic bracing (per the restraint manufacturer's listing)

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following for the Engineer's and structural engineer of record's review and return prior to procurement or fabrication of isolation and restraint components:

Vibration isolation schedule listing, for each isolated equipment tag, the equipment operating weight and distribution, the lowest operating speed and disturbing frequency, the selected isolator type, the rated load, the rated and operating static deflection, and the resulting isolation efficiency
Isolator product data for each isolator type, including load-versus-deflection data, spring free height and solid height, lateral-to-vertical stiffness ratio for spring isolators, and the durometer of elastomeric elements per ASTM D2240
Base product data and structural calculations for inertia bases and structural-steel bases, including base weight, reinforcement, and isolator locations
Flexible pipe connector and flexible conduit product data, including pressure and temperature rating, movement capability, and end connection type
Thrust restraint product data for high-static fans, including spring rate and the calculated thrust force
Seismic restraint schedule listing, for each restrained component and distribution run, the seismic design force, the restraint type, the brace spacing, and the attachment to the structure
Seismic design force calculations per ASCE/SEI 7 Chapter 13 for each restrained component and distribution system, prepared and stamped by a licensed professional engineer, showing the parameters used (ap, Rp, Ip, the component weight, and the resulting Fp)
Anchorage calculations for each attachment to concrete or structural steel, prepared and stamped by a licensed professional engineer, citing the anchor evaluation report and demonstrating adequacy for the seismic design force per ACI 318 Chapter 17
Special seismic certification (ICC-ES AC156 shake-table test report or equivalent) for each active or designated seismic component required to function during or after the design earthquake
Anchor evaluation reports (ICC-ES ESR or equivalent) for each post-installed anchor, confirming qualification for cracked concrete and seismic loading per ACI 355.2 or ACI 355.4
Manufacturer's installation instructions for each isolation and restraint component

Action Submittals Requiredcheckbox

☑ Vibration isolation schedule (per equipment tag)

☐ Isolator product data with load-deflection curves

☐ Inertia and structural base data and calculations

☐ Flexible pipe connector and flexible conduit data

☐ Thrust restraint data for high-static fans

☐ Seismic restraint schedule (per component and run)

☐ ASCE 7 Chapter 13 seismic force calculations (PE-stamped)

☐ Anchorage calculations per ACI 318 Chapter 17 (PE-stamped)

☐ Special seismic certification (AC156) for active components

☐ Anchor evaluation reports (ICC-ES ESR) for post-installed anchors

☐ Manufacturer's installation instructions

3.1.2 Fabrication, procurement, and installation shall not proceed until the associated action submittals have been reviewed and returned with no outstanding engineering questions.

3.2 Closeout Submittals

3.2.1 At substantial completion the Contractor shall provide the following closeout submittals:

Operation and maintenance data including isolator adjustment instructions, the recommended re-leveling and limit-stop reset procedure, and the seismic restraint inspection checklist
As-installed isolation and restraint schedule reflecting any field-approved substitutions or relocations
Special inspection reports prepared by the approved special inspector documenting verification of anchorage installation, post-installed anchor torque and embedment, and restraint configuration per IBC Chapter 17
Field verification records confirming that isolated equipment is floating free on its isolators with all shipping restraints removed and that all restrained isolator limit stops are set to the operating clearance
Manufacturer's special seismic certification labels and supporting test reports for active and designated seismic components

Required Closeout Submittalscheckbox

☑ Operation and maintenance data (adjustment and inspection)

☑ As-installed isolation and restraint schedule

☑ Special inspection reports per IBC Chapter 17

☑ Field verification of free-floating equipment and limit-stop settings

☑ Special seismic certification labels and test reports

4 Quality Assurance

4.1 Manufacturer Qualifications

4.1.1 Isolation and seismic restraint components shall be the products of a manufacturer regularly engaged in the design and production of vibration isolation and seismic restraint hardware for commercial MEP service.

NOTE A single isolation and restraint manufacturer should furnish the isolators, bases, restraints, and snubbers for a given equipment item so that the load path is coordinated by one source. (4.1.2)

4.2 Design Responsibility

4.2.1 Seismic design forces and restraint and anchorage details shall be designed by a professional engineer licensed in the project jurisdiction and retained by the Contractor or the restraint manufacturer.

4.2.2 The seismic restraint design shall be reviewed and accepted by the structural engineer of record before installation.

4.2.3 Delegated design of seismic restraint by the restraint manufacturer's engineer is standard industry practice, but the structural engineer of record retains responsibility for the building structure that receives the restraint loads; the two scopes must be reconciled in writing.

4.3 Special Seismic Certification

4.3.1 Active and designated seismic components that are required by ASCE/SEI 7 Section 13.2.2 to function during or after the design earthquake shall be certified by shake-table testing in accordance with ICC-ES AC156, by approved analysis, or by experience data, as accepted by the building official.

NOTE The component importance factor Ip equals 1.5 for components designated to function for life-safety purposes after an earthquake, for components conveying or supporting hazardous materials, and for components in or attached to designated essential facilities; certification by shake-table testing is the prevailing method for such active equipment. (4.3.2)

NOTE In jurisdictions and on facility types governed by the California HCAI (formerly OSHPD) program, components may carry an OSHPD Special Seismic Certification Preapproval (OSP) or the manufacturer's anchorage details may carry an OSHPD Preapproval of Manufacturer (OPM); both are issued on the basis of AC156 shake-table testing. (4.3.3)

4.3.4 Special seismic certification datasheet

Special Seismic Certification Basisselect

Not required — component is not active and not designated seismic (Ip = 1.0)

Shake-table tested per ICC-ES AC156

Certified by approved analysis

Certified by experience data

OSHPD/HCAI Special Seismic Certification Preapproval (OSP)

4.4 Special Inspection

4.4.1 Where seismic restraint of nonstructural components is required, the installation shall be subject to special inspection by an approved special inspector in accordance with IBC Chapter 17.

4.4.2 Special inspection shall include verification of post-installed anchor type, embedment, hole cleaning, and installation torque or adhesive cure, and verification that restraint and snubber configuration matches the accepted design.

NOTE Post-installed anchors are the most frequently mis-installed element of a seismic restraint system — wrong anchor type, insufficient embedment, an uncleaned hole for an adhesive anchor, or installation in a cracked or edge-distance-deficient location — and the special inspection is the control that catches these before they are concealed. (4.4.3)

5 Seismic Design Basis

5.1 Seismic Design Category and Exemptions

5.1.1 The seismic design category (SDC), the design spectral response accelerations, and the applicable exemptions shall be established from the structural drawings and the governing building code for the project.

NOTE ASCE/SEI 7 Chapter 13 exempts certain nonstructural components from seismic restraint, including, subject to the conditions stated in the standard, components in Seismic Design Category A and B, many mechanical and electrical components in SDC C, distribution systems and components supported by hangers within the length limit of the standard, and small or light components below the weight and height thresholds of the standard. (5.1.2)

5.1.3 An exemption shall be applied only after confirming that every condition the standard attaches to that exemption is met, including the flexible-connection condition for distribution systems and the positive-attachment condition for components whose anchorage is detailed on the drawings.

5.1.4 Seismic design category datasheet

Seismic Design Category (SDC)select

A

B

C

D

E

F

Per drawings — structural general notes

5.1.5 Component importance factor datasheet

Component Importance Factor (Ip)radio

● 1.0 — standard component (no post-earthquake function required)

○ 1.5 — designated/active component (life-safety function, hazardous contents, or essential facility)

Per drawings — structural general notes

5.2 Seismic Design Force

5.2.1 The horizontal seismic design force Fp on each component, its supports, and its attachments shall be computed in accordance with ASCE/SEI 7 Chapter 13 using the component amplification factor, the component response modification factor, the component importance factor Ip, and the component operating weight.

5.2.2 The vertical seismic force component shall be added to the load on supports and anchorage as required by ASCE/SEI 7 Chapter 13.

5.2.3 Where the weight of a component equals or exceeds 20 percent of the combined effective seismic weight of the component and its supporting structure, the component shall be designed as a nonbuilding structure rather than under the simplified nonstructural-component provisions.

NOTE The ASCE 7-22 nonstructural force equation revised the prior approach to account for the dynamic response of the supporting structure and the ductility of the component anchorage; the calculation shall use the equation of the code edition adopted by the project jurisdiction, not a remembered formula from a superseded edition. (5.2.4)

6 Vibration Isolation Selection

6.1 Selection Basis

6.1.1 Each isolated equipment item shall be provided with isolators selected for the required static deflection at the equipment operating weight so that the isolator natural frequency is far enough below the equipment disturbing frequency to achieve the required isolation efficiency.

NOTE Isolator selection follows from one governing ratio: the equipment disturbing frequency divided by the isolator natural frequency. A larger ratio gives more isolation. Because the isolator natural frequency falls as static deflection rises, the selection reduces to choosing an isolator whose operating static deflection is large enough for the required isolation. (6.1.2)

NOTE Effective isolation begins only where the disturbing frequency exceeds the isolator natural frequency by a factor of at least the square root of two; below that ratio the isolator amplifies rather than isolates. Practical design targets a frequency ratio of three or more, corresponding to roughly 90 percent isolation, and five or more for the 95 percent and greater isolation expected over noise-sensitive spaces. (6.1.3)

NOTE Selecting an isolator by load rating alone, without confirming the operating static deflection against the equipment's lowest disturbing frequency, is the most common vibration isolation error and produces equipment that is mounted on springs yet still transmits objectionable vibration to the structure. (6.1.4)

6.2 Disturbing Frequency

6.2.1 The lowest disturbing frequency shall be taken as the equipment's lowest normal operating rotational speed, including the minimum speed of any variable-speed equipment, because isolation efficiency is governed by the lowest, not the nominal, operating frequency.

6.2.2 Variable-speed equipment shall be isolated for its minimum operating speed; an isolator selected for full-speed operation provides far less isolation at reduced speed, where the disturbing frequency approaches the isolator natural frequency.

6.2.3 Lowest operating speed datasheet

Equipment Lowest Operating Speedrange

RPM

2003004006009001160175035003600

Per drawings — equipment schedule

6.3 Required Static Deflection

6.3.1 The required operating static deflection shall be selected for the equipment type, the equipment lowest operating speed, and the location of the equipment in the building, following the selection guidance of the ASHRAE Handbook — HVAC Applications, Chapter 49.

NOTE Equipment on a stiff slab on grade requires less static deflection than the same equipment on an upper floor, because a flexible long-span floor has its own low natural frequency and requires a softer isolator to remain well below it; a slab-on-grade selection installed on an upper floor is a frequent cause of transmitted vibration. (6.3.2)

NOTE Lower-speed equipment requires greater static deflection than higher-speed equipment for the same isolation efficiency, because the lower disturbing frequency demands a correspondingly lower isolator natural frequency. (6.3.3)

6.3.4 Required static deflection datasheet

Required Operating Static Deflectionrange

in.

0.050.10.250.50.7511.522.533.54

6.3.5 Equipment location datasheet

Equipment Location (Floor Stiffness)select

Slab on grade (stiff)

Upper floor, short span (under ~20 ft)

Upper floor, medium span (~20 to 30 ft)

Upper floor, long span (over ~30 ft, flexible)

Roof structure

Per drawings — structural floor framing plans

7 Isolator Types

7.1 Isolator Type Selection

7.1.1 The isolator type shall be selected to provide the required static deflection at the equipment operating weight, with a restrained (seismic) type used wherever the equipment also requires seismic restraint.

NOTE Elastomeric (neoprene) mounts and pads provide small static deflection and are the economical selection for higher-speed equipment with low isolation requirements; steel spring isolators provide the larger static deflection required for low-speed equipment and noise-sensitive locations; and air springs provide very large effective deflection where the lowest natural frequency is required. (7.1.2)

7.1.3 Isolator type datasheet

Isolator Typeselect

Ribbed or waffle neoprene pad (small deflection, vibration pads under non-critical equipment)

Rubber-in-shear / molded neoprene mount (deflection up to ~0.5 in.)

Open (free-standing) steel spring isolator

Restrained (seismic) steel spring isolator with integral limit stops

Spring isolator with neoprene acoustic base pad (spring plus pad)

Air spring (pneumatic isolator, very low natural frequency)

7.2 Spring Isolator Construction

7.2.1 Steel spring isolators shall have springs selected so that the lateral stiffness is at least equal to the rated vertical stiffness and so that the spring provides additional travel to solid of at least 50 percent of the rated operating deflection.

NOTE A laterally stable spring (lateral-to-vertical stiffness ratio of at least one) and adequate travel to solid prevent the spring from short-circuiting against its own coils or rocking under load, either of which destroys isolation. (7.2.2)

7.2.3 Open spring isolators shall include a non-skid, sound-isolating neoprene acoustic pad bonded to the base plate to interrupt high-frequency vibration transmission through the spring steel.

7.2.4 Spring isolators shall include a leveling bolt and means to adjust the equipment to level and to the operating height.

7.3 Restrained Spring Isolators

7.3.1 Equipment that requires both vibration isolation and seismic restraint shall be mounted on restrained spring isolators that provide the operating static deflection during normal service and limit motion in all directions during a seismic event.

7.3.2 Restrained spring isolators shall include integral limit stops with a resilient (elastomeric) snubbing element so that seismic motion is arrested without metal-to-metal impact.

7.3.3 The limit stops shall be set to clear the operating motion of the equipment so that the isolator floats free during normal operation and engages only on seismic or startup excursion.

NOTE Bolting isolated equipment rigidly to the structure to provide seismic restraint defeats the isolation entirely — the bolt becomes a rigid vibration path; restrained isolators exist precisely so that restraint and isolation coexist, and a rigid restraint shall never be substituted for a restrained isolator on isolated equipment. (7.3.4)

7.4 Vibration Hangers

7.4.1 Suspended equipment, piping, and ductwork requiring isolation shall be hung on vibration hangers selected for the required static deflection.

7.4.2 Spring hangers shall be used where the required static deflection exceeds that available from an elastomeric hanger; combination spring-and-neoprene hangers shall be used where both low-frequency isolation and high-frequency (structure-borne noise) interruption are required.

7.4.3 The hanger box shall be designed so that the hanger rod does not contact the box at any point in the operating range; rod contact short-circuits the isolation and is a common installation defect.

7.4.4 Vibration hanger datasheet

Vibration Hanger Typeselect

Neoprene-in-shear hanger (small deflection)

Steel spring hanger

Combination spring and neoprene hanger

Not applicable — floor-mounted equipment

8 Equipment Bases

8.1 Base Type Selection

8.1.1 Each isolated floor-mounted equipment item shall be provided with the base type required to distribute the isolator loads, to maintain alignment of the equipment, and to provide the mass needed for stable low-frequency isolation.

NOTE A rail or structural-steel base spreads isolator loads and keeps a long or flexible equipment frame aligned; an inertia base adds mass that lowers the assembly's center of gravity, reduces motion at startup and shutoff, and is used for close-coupled pumps and high-thrust equipment where the added mass stabilizes the isolated system. (8.1.2)

8.1.3 Base type datasheet

Equipment Isolation Baseselect

Isolators mounted directly to equipment feet (no base)

Structural-steel rail base

Structural-steel perimeter base

Concrete-filled inertia base (steel frame, reinforced concrete fill)

Curb-mounted isolation (roof-mounted equipment)

8.2 Inertia Bases

8.2.1 Inertia bases shall be a welded structural-steel perimeter frame with reinforcing steel and concrete fill, with isolator brackets located outside the frame so that isolators can be serviced without lifting the base.

8.2.2 Inertia base mass shall be selected per the equipment manufacturer's and isolation manufacturer's recommendation, commonly 1 to 1.5 times the supported equipment weight for pumps and similar equipment, to provide stable isolation and limit dynamic motion.

8.2.3 Close-coupled pumps shall be mounted on an inertia base because the short coupling makes the assembly sensitive to motion; the inertia base mass restrains the reaction to flow-induced and starting torques.

8.3 Curb-Mounted Equipment

8.3.1 Roof-mounted equipment requiring isolation shall be mounted on an isolation curb that provides the required static deflection while maintaining a weathertight, wind-resistant, and seismically restrained connection to the roof structure.

8.3.2 Isolation curbs shall integrate the spring isolation, the seismic restraint, and the weatherproofing in a single assembly so that the roof penetration is not compromised by separate field-installed isolators.

9 Flexible Connections and Thrust Restraints

9.1 Flexible Pipe Connectors

9.1.1 Each isolated equipment item with a piping connection shall be connected to its piping through a flexible pipe connector at the equipment so that the piping does not short-circuit the isolation and so that the connector accommodates the isolated equipment's motion.

9.1.2 Flexible pipe connectors shall be rated for the system operating pressure and temperature and shall be installed at the published face-to-face length without compression or extension.

9.1.3 A control rod or thrust restraint shall be provided across flexible connectors where the unrestrained pressure thrust would over-extend the connector or impose thrust on the equipment nozzle.

9.1.4 Piping shall be independently supported and, where required, isolated for the first several hangers away from isolated equipment so that the piping does not transmit equipment vibration through the building or load the equipment nozzle; refer to Hydronic PipingHydronic PipingResolves to the current edition.sync/hydronic-piping for the isolated-pipe-support detail.

9.1.5 Flexible pipe connector datasheet

Flexible Pipe Connector Typeselect

Spherical (twin-sphere) elastomeric connector

Single-arch elastomeric connector

Braided stainless steel flexible hose with control rods

Not applicable — no piping connection

9.2 Flexible Conduit and Duct Connections

9.2.1 Electrical connections to isolated equipment shall be made with a length of flexible conduit looped to accommodate the equipment's isolated motion without transmitting vibration into the raceway system; refer to Raceways And ConduitRaceways and ConduitResolves to the current edition.sync/raceways-and-conduit.

9.2.2 Ducted connections to isolated air-handling equipment shall include a flexible duct connector at the equipment so that fan vibration is not transmitted into the ductwork; refer to HVAC DuctworkHVAC DuctworkResolves to the current edition.sync/hvac-ductwork.

9.3 Thrust Restraints

9.3.1 Fans developing high static pressure shall be provided with thrust restraints arranged to limit the fan's startup and operating movement caused by the air thrust reaction without short-circuiting the vibration isolation.

9.3.2 Thrust restraints shall be horizontal spring assemblies installed on each side of the fan parallel to the airflow thrust, preloaded and adjusted to limit movement to the manufacturer's allowable value.

NOTE A high-static fan on soft isolators will lurch when started and may pull its flexible duct connector apart or surge against the ductwork; the thrust restraint absorbs the thrust reaction while preserving the isolation. (9.3.3)

9.3.4 Thrust restraint datasheet

Thrust Restraint Requirementradio

○ Required — fan static pressure high enough to cause objectionable startup movement

● Not required — low-static fan or thrust within isolator allowable movement

10 Seismic Restraint of Equipment

10.1 Restraint of Isolated Equipment

10.1.1 Vibration-isolated equipment requiring seismic restraint shall be restrained by restrained (seismic) spring isolators or by seismic snubbers arranged around the equipment, not by a rigid attachment.

10.1.2 Seismic snubbers, where used in place of restrained isolators, shall be installed with an air gap and a resilient snubbing element set to clear the equipment's operating motion and to engage only on seismic excursion.

10.1.3 Restraint type for isolated equipment datasheet

Seismic Restraint of Isolated Equipmentselect

Restrained spring isolators with integral limit stops

Open spring isolators with separate all-directional seismic snubbers

Restrained elastomeric mounts

Not required — equipment exempt from seismic restraint

10.2 Restraint of Non-Isolated Equipment

10.2.1 Equipment that does not require vibration isolation but does require seismic restraint shall be anchored directly to the structure or to its housekeeping pad through anchorage designed for the seismic design force.

10.2.2 Direct-anchored equipment datasheet

Non-Isolated Equipment Anchorageselect

Cast-in anchor bolts in housekeeping pad or slab

Post-installed expansion anchors (mechanical)

Post-installed adhesive anchors

Welded or bolted to structural steel

10.3 Anchorage to Concrete

10.3.1 Anchorage of equipment, bases, isolators, and snubbers to concrete shall be designed in accordance with ACI 318 Chapter 17 for the seismic design force, including the reduction factors and ductility provisions the code requires for seismic anchorage.

10.3.2 Cast-in anchors shall be used in new housekeeping pads and slabs where the anchor locations are known at the time of the concrete pour, because cast-in anchors develop full capacity without the edge-distance and cracked-concrete penalties of post-installed anchors.

10.3.3 Post-installed anchors shall be qualified for cracked concrete and for seismic loading by an evaluation report (ICC-ES ESR or equivalent) per ACI 355.2 (mechanical) or ACI 355.4 (adhesive), and shall be installed at the embedment, spacing, and edge distance the evaluation report requires.

10.3.4 Adhesive anchors installed in a horizontal or upwardly inclined orientation to resist sustained tension shall be installed by personnel certified for adhesive anchor installation and shall be subject to continuous special inspection, as ACI 318 requires.

10.3.5 Insufficient edge distance is the most common post-installed anchor deficiency near the edge of a housekeeping pad; the pad shall be sized so that every anchor meets the edge distance its evaluation report requires, which is why pads are extended beyond the equipment footprint.

10.3.6 Housekeeping pad dimensions and embedded anchorage shall be coordinated with Concrete PadsConcrete Equipment PadsResolves to the current edition.sync/concrete-pads.

10.3.7 Anchor type datasheet

Anchor Type for Restraint to Concreteselect

Cast-in headed anchor or anchor bolt

Post-installed expansion anchor (mechanical, seismic-qualified)

Post-installed undercut anchor (seismic-qualified)

Post-installed adhesive anchor (seismic-qualified)

11 Seismic Restraint of Distribution Systems

11.1 Distribution Restraint Basis

11.1.1 Piping, ductwork, conduit, and cable tray requiring seismic restraint shall be braced transversely and longitudinally in accordance with ASCE/SEI 7 Chapter 13 and the SMACNA Seismic Restraint Manual, except where a referenced system standard (such as NFPA 13 for sprinkler piping) governs.

NOTE A transverse brace resists motion perpendicular to the run and a longitudinal brace resists motion along the run; a length of pipe or duct needs both, because the two act on independent directions of seismic motion. (11.1.2)

NOTE Distribution systems suspended by hangers are exempt from seismic bracing only where every condition of the applicable ASCE/SEI 7 exemption is met, including the hanger length limit and the flexible-connection provision; the exemption shall be confirmed run by run, not assumed for the project. (11.1.3)

11.2 Brace Spacing

11.2.1 Transverse and longitudinal brace spacing shall not exceed the maximum spacing established by the SMACNA Seismic Restraint Manual selection tables for the system, size, and seismic load, and shall not exceed the spacing shown on the accepted restraint submittal.

NOTE As a starting point before the SMACNA tables are applied, transverse braces are commonly spaced at intervals up to 40 ft and longitudinal braces up to 80 ft, with closer spacing required for larger or heavier runs and higher seismic loads. (11.2.2)

11.2.3 A longitudinal brace shall engage the run through a clamp or attachment that cannot slip along the pipe or duct, so that the brace actually develops the longitudinal restraint it is credited for.

11.2.4 Transverse brace spacing datasheet

Maximum Transverse Brace Spacingrange

ft

10152025303540

11.2.5 Longitudinal brace spacing datasheet

Maximum Longitudinal Brace Spacingrange

ft

20304050607080

11.3 Brace Type

11.3.1 Distribution systems shall be braced with cable (aircraft cable) bracing, with rigid strut bracing, or with a combination, as required by the system and as shown on the accepted restraint submittal.

NOTE Cable bracing resists tension only and is installed in opposing pairs so that each direction of motion is taken by a cable in tension; rigid strut bracing resists both tension and compression and so can restrain a direction with a single member, and is preferred where overhead space or geometry will not accommodate the splay of cable braces. (11.3.2)

11.3.3 Cable braces shall be installed at the splay angle within the range its listing permits, because both an excessively shallow and an excessively steep brace angle reduce the brace's effectiveness.

11.3.4 Brace type datasheet

Distribution Brace Typeselect

Cable (aircraft cable) bracing — tension only, opposing pairs

Rigid strut bracing — tension and compression

Combination cable and rigid bracing

11.4 Flexibility at Joints and Connections

11.4.1 Flexibility shall be provided in piping, ductwork, and conduit where a run crosses a seismic separation joint or a building expansion joint, and at the connection between a braced run and an isolated or independently supported component, so that differential movement does not rupture the run.

NOTE Restraint and flexibility are complementary, not contradictory: the braces hold the run to one structural element, and the flexible element absorbs the relative movement where that run meets a differently moving element, such as across a seismic joint or at a flexibly mounted piece of equipment. (11.4.2)

12 Installation

12.1 Equipment Location and Arrangement

12.1.1 Equipment locations, housekeeping pad locations, and the routing of braced distribution runs shall be as indicated on the mechanical, electrical, and plumbing plans.

12.1.2 Isolator and restraint locations on each equipment item shall be per the isolation and restraint details and the accepted restraint submittal.

12.2 Setting Isolated Equipment

12.2.1 Isolated equipment shall be installed so that, after all shipping restraints and blocking are removed, the equipment floats free on its isolators and bears no load through any rigid path to the structure.

NOTE All shipping bolts, blocking, and transit restraints shall be removed after the equipment is set and before startup; equipment left blocked transmits full vibration to the structure exactly as if it had no isolators. (12.2.2)

12.2.4 Where a piping or duct connection imposes a load that shifts the equipment off level, the connection shall be corrected rather than compensated for by uneven isolator adjustment.

12.3 Setting Restrained Isolators and Snubbers

12.3.1 Restrained isolator limit stops and snubber air gaps shall be set to the clearance shown on the accepted submittal so that the restraint clears the operating motion and engages only on seismic excursion.

12.3.2 After the equipment is floating free, the limit-stop clearance shall be verified on every restrained isolator; a limit stop left bottomed against the equipment short-circuits the isolation in the same way a shipping bolt does.

12.4 Installing Distribution Bracing

12.4.1 Transverse and longitudinal braces shall be installed at the spacing and the attachment details shown on the accepted restraint submittal and shall attach to building structure, not to other nonstructural systems or to suspended ceilings.

12.4.2 A seismic brace shall not be attached to another distribution system, to the suspended ceiling grid, or to any element that is not part of the building structure, because the brace can only restrain the run if its far end is anchored to something that does not move with it.

12.4.3 Bracing attachments to the structure shall use the connector type qualified for the structure type (concrete insert, beam clamp, or welded attachment) and the seismic load.

12.5 Installing Anchors

12.5.1 Post-installed anchors shall be installed at the embedment, hole diameter, spacing, and edge distance the anchor's evaluation report requires, with the hole drilled and cleaned by the method the report specifies.

12.5.2 Adhesive anchor holes shall be cleaned exactly as the manufacturer's published instructions require, because adhesive anchor capacity depends entirely on the bond to clean concrete and an uncleaned hole can lose most of its rated capacity.

12.5.3 Anchors shall not be installed in cracked or spalled concrete or closer to an edge than the evaluation report permits; where field conditions prevent compliant installation, the condition shall be referred to the engineer before the anchor is set.

13 Field Verification

13.1 Isolation Verification

13.1.1 After installation and removal of all shipping restraints, the Contractor shall verify that each isolated equipment item is floating free, is level, and is at its operating height, and that no rigid path bypasses the isolators.

13.1.2 The Contractor shall verify that piping, conduit, and duct connections to isolated equipment are made through their flexible connectors and do not load or short-circuit the isolation.

13.2 Restraint Verification

13.2.1 The Contractor shall verify that restrained isolator limit stops and snubber gaps are set to the specified operating clearance on every restrained isolator and snubber.

13.2.2 The Contractor shall verify that distribution braces are installed at the specified spacing, at compliant angles, and attached to building structure, and shall make the installation available for the special inspector's verification per IBC Chapter 17.

14 Delivery, Storage, and Handling

14.1 Isolation and restraint components shall be delivered in original packaging, labeled with the equipment tag or run they serve, and stored indoors in a clean, dry location.

14.2 Spring isolators and restrained isolators shall be protected from distortion and corrosion in storage and shall not be used to support construction loads before the equipment is set.

14.3 Adhesive anchor cartridges shall be stored within the temperature range and shall not be used after the shelf-life date the manufacturer marks on the cartridge, because expired or temperature-abused adhesive does not develop rated bond strength.

15 Warranty

15.1 The isolation and restraint manufacturer shall warrant the isolators, bases, restraints, snubbers, and connectors against defects in materials and workmanship for the period specified below, beginning from the date of substantial completion.

15.2 Warranty period datasheet

Warranty Periodselect

1 year from substantial completion (minimum)

2 years from substantial completion

5 years from substantial completion (extended)

15.3 The Contractor shall warrant the installation workmanship — including isolator setting and adjustment, limit-stop and snubber clearances, brace installation, flexible connections, and anchorage — for one year from the date of substantial completion.

16 Spare Parts

NOTE The following spare parts datasheet establishes the spares to be delivered at substantial completion. (16.1)

16.2 Spare parts shall be delivered to the Owner in original packaging, each tagged with the corresponding equipment tag, component model, and date of delivery.

Spare Parts at Substantial Completioncheckbox

☐ Spare restrained spring isolators — one per isolator size and rating used

☐ Spare seismic snubber elastomeric elements — one set per snubber size

☑ Spare flexible pipe connectors — one per connector size

☐ Spare vibration hanger elements — one per hanger type

☐ Adhesive anchor installation tools and cleaning brushes for the anchors used