Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
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title: Vibration Isolation and Seismic Restraint
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### The seismic restraint design shall be reviewed and accepted by the structural engineer of record before installation.
−### 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. {note}
+### 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.
## Special Seismic Certification {toc}
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### 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. {note}
−### 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. {note}
+### 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.
### Seismic design category datasheet {toc}
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### The vertical seismic force component shall be added to the load on supports and anchorage as required by ASCE/SEI 7 Chapter 13.
−### 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}
+### 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.
### 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. {note}
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### 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.
−### 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. {note}
+### 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.
### Lowest operating speed datasheet {toc}
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### 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.
−### 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}
+### 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.
### 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. {note}
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### 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.
−### 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. {note}
+### 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.
### Vibration hanger datasheet {toc}
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### 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.
−### 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. {note}
+### 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.
## Curb-Mounted Equipment {toc}
### 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.
−### 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. {note}
+### 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.
# Flexible Connections and Thrust Restraints {toc}
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### 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.
−### 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. {note}
+### 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.
−### 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 [[sync/hydronic-piping]] for the isolated-pipe-support detail. {note}
+### 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 [[sync/hydronic-piping]] for the isolated-pipe-support detail.
### Flexible pipe connector datasheet {toc}
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### 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.
−### 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. {note}
+### 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.
### 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.
### 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.
−### 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. {note}
+### 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.
### Housekeeping pad dimensions and embedded anchorage shall be coordinated with [[sync/concrete-pads]].
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### 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. {note}
−### 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. {note}
+### 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.
### Transverse brace spacing datasheet {toc}
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### 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. {note}
−### 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. {note}
+### 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.
### Brace type datasheet {toc}
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### Spring isolators shall be adjusted so that the equipment is level and at the operating height and so that each spring carries its design share of the load with the rated operating deflection.
−### 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. {note}
+### 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.
## Setting Restrained Isolators and Snubbers {toc}
### 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.
−### 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. {note}
+### 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.
## Installing Distribution Bracing {toc}
### 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.
−### 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. {note}
+### 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.
### 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.
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### 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.
−### 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. {note}
+### 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.
−### 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. {note}
+### 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.
# Field Verification {toc}
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## The following spare parts datasheet establishes the spares to be delivered at substantial completion. {note}
+## Spare parts shall be delivered to the Owner in original packaging, each tagged with the corresponding equipment tag, component model, and date of delivery.
+
```datasheet
label: Spare Parts at Substantial Completion
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default: "Spare flexible pipe connectors — one per connector size"
```
−
−## Spare parts shall be delivered to the Owner in original packaging, each tagged with the corresponding equipment tag, component model, and date of delivery.