230548_mech_vibration_seismic_controls.pdf

CHICOPEE ARMORY REHABILITATION MMD PROJECT NO. 985101

CHICOPEE, MASSACHUSETTS ISSUED FOR BID - 05/20/11

10090 MECHANICAL VIBRATION AND SEISMIC CONTROLS 230548 - 1

SECTION 230548

MECHANICAL VIBRATION AND SEISMIC CONTROLS

PART 1 - GENERAL

1.1 RELATED DOCUMENTS

A. Drawings and general provisions of the Contract, including General and Supplementary

Conditions and Division 1 Specification Sections, apply to this Section.

B. The requirements of Section 230000, “Basic Mechanical Requirements” apply to work defined by the Section.

C. The requirements of Section 230500, “Basic Mechanical Materials and Methods” apply to work defined by the Section.

1.2 SUMMARY

A. This Section includes the following:

1. Vibration Isolators.

2. Duct and Pipe Isolators.

3. Seismic Restraint Devices.

B. Related Sections include the following:

1. Section 230500, “Basic Mechanical Materials and Methods” for thermal expansion compensation in piping systems.

2. Section 230529, “Hangers and Supports” for piping, duct, and equipment hangers and supports as well as requirements for strut components.

1.3 DEFINITIONS

A. Av: Effective peak velocity related acceleration coefficient.

B. OSHPD: Office of Statewide Health Planning & Development for the State of California.

OSHPD assigns a unique anchorage preapproval "R" number to each seismic restraint it tests.

The number describes a specific device applied as tested.

C. Withstand: The term "withstand" means "the unit will remain in place without separation of any parts from the device when subjected to the seismic forces specified and the unit will be fully operational after the seismic event."

1.4 SEISMIC REQUIREMENTS

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A. General: Performance requirements to be used in the design of seismic controls are as identified herein;

1. Seismic Design Category: B

2. Seismic spectral response acceleration for short periods, SDS = .245.

1.5 Applicability: Seismic bracing is not required for mechanical systems except for components critical to the life safety of occupants, such as sprinkler systems and components containing hazardous materials. SUBMITTALS

A. General: See Division 1 “Submittal Procedures” for general submittal and product substitution requirements.

B. Pre-Construction Submittals: Submit the following items prior to commencing with installations.

1. Product Data: Include load deflection curves for each vibration isolation device.

2. Shop Drawings: Signed and sealed by a qualified professional engineer licensed in the

Commonwealth of Massachusetts.. Include the following:

a. Design Calculations: Calculate requirements for selecting vibration isolators and seismic restraints and for designing vibration isolation bases.

b. Riser Supports: Include riser diagrams and calculations showing anticipated expansion and contraction at each support point, initial and final loads on building structure, spring deflection changes, and seismic loads. Include certification that riser system has been examined for excessive stress and that none will exist.

c. Vibration Isolation Base Details: Detail fabrication, including anchorages and attachments to structure and to supported equipment. Include auxiliary motor slides and rails, base weights, equipment static loads, power transmission, component misalignment, and cantilever loads.

d. Seismic-Restraint Details: Detail fabrication and attachment of seismic restraints and snubbers. Show anchorage details and indicate quantity, diameter, and depth of penetration of anchors.

e. Submittals for Interlocking Snubbers: Include load deflection curves up to 1/2-inch deflection in x, y, and z planes.

3. Welding certificates.

4. Manufacturer Seismic Qualification Certification: Submit certification that all specified equipment will withstand seismic forces identified in "Performance Requirements"

Article above. Include the following:

a. Basis for Certification: Indicate whether withstand certification is based on actual test of assembled components or on calculations.

b. Dimensioned Outline Drawings of Equipment Unit: Identify center of gravity and locate and describe mounting and anchorage provisions.

c. Detailed description of equipment anchorage devices on which the certification is based and their installation requirements.

1.6 QUALITY ASSURANCE

A. Seismic-restraint devices shall have horizontal and vertical load testing and analysis performed according to OSHPD and shall bear anchorage pre-approval "R" number, from OSHPD or another agency acceptable to authorities having jurisdiction, showing maximum seismic-

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restraint ratings. Ratings based on independent testing are preferred to ratings based on calculations. If pre-approved ratings are not available, submittals based on independent testing are preferred. Calculations (including combining shear and tensile loads) to support seismic-restraint designs must be signed and sealed by a qualified professional engineer. Testing and calculations must include both shear and tensile loads and 1 test or analysis at 45 degrees to the weakest mode.

B. Welding: Qualify procedures and personnel according to AWS D1.1, "Structural Welding

Code--Steel."

1.7 COORDINATION

A. Coordinate size and location of concrete bases. Cast anchor-bolt inserts into base. Concrete, reinforcement, and formwork requirements are specified in Division 3.

B. Coordinate installation of roof curbs, equipment supports, and roof penetrations with roofing system. Refer to Division 7 Section “Thermoplastic Polyolefin Roofing”.

PART 2 - PRODUCTS

2.1 MANUFACTURERS

A. Manufacturers: Subject to compliance with requirements, provide products by one of the manufacturers listed below.

B. Vibration Isolators:

1. Ace Mounting Co., Inc.

2. Amber/Booth Company, Inc.

3. B-Line Systems, Inc.

4. Isolation Technology, Inc.

5. Kinetics Noise Control, Inc.

6. Mason Industries, Inc.

7. Vibration Mountings & Controls/Korfund.

C. Duct and Pipe Vibration Isolators

1. Mason Industries, Inc.

2. Mason-Mercer, (Mason Industries, Inc. – Mercer Rubber Co.)

3. The Metraflex Co.

4. Amber/Booth Company, Inc.

5. Vibration Mountings & Controls/Korfund.

D. Seismic Restraint Devices:

1. Amber/Booth Company, Inc.

2. B-Line Systems, Inc.

3. Kinetics Noise Control, Inc.

4. Loos & Co., Inc.; Cableware Technology Division.

5. Mason Industries, Inc.

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6. TOLCO Incorporated.

7. Unistrut Diversified Products Co.; Wayne Manufacturing Division.

8. Vibration Mountings & Controls/Korfund.

2.2 VIBRATION ISOLATORS

A. General: The following applies to items specified in the paragraphs below.

1. Minimum static deflections are identified in the schedule at the end of Part 3.

2. Vibration Isolators which have a seismic function as well, (those which incorporate limit stops and/or snubbers) shall not be constructed of aluminum of cast iron materials.

B. Elastomeric Grommet, (Bushing): Oil- and water-resistant elastomer, bolt-isolating bushing.

1. Material: Bridge Bearing Neoprene.

2. Basis of Design: Mason Industries, Inc. Type HG.

C. Elastomeric Isolator Pads: Oil- and water-resistant elastomer, arranged in single or multiple layers, molded with a non-slip pattern, factory cut to sizes that match requirements of supported equipment.

1. Material: Standard neoprene.

2. Shims, (between multiple layers): 16 ga. Steel.

3. Basis of Design: Mason Industries, Inc. Types W, SW & layered combinations thereof.

D. Elastomeric Isolator Pads & Plates: Oil- and water-resistant elastomer, arranged in single or multiple layers, molded with a non-slip pattern and galvanized steel baseplates of sufficient stiffness for uniform loading over pad area, and factory cut to sizes that match requirements of supported equipment.

1. Material: Standard neoprene or bridge-bearing neoprene, complying with

AASHTO M 251.

2. Shims, (between multiple layers): 16 ga. Steel.

3. Basis of Design: Mason Industries, Inc. Type SWM & layered combinations thereof.

E. Elastomeric Mounts (Mason Spec. A): Double-deflection type, with molded, oil-resistant neoprene isolator elements with factory-drilled, encapsulated top plate for bolting to equipment and with baseplate for bolting to structure. Color-code or otherwise identify to indicate capacity range.

1. Vibration Isolating Material: Neoprene.

2. Basis of Design: Mason Industries, Inc. Type ND.

F. Restrained Elastomeric Mounts: All-directional elastomeric mountings with seismic restraint.

1. Materials: Cast-ductile-iron housing containing two separate and opposing, molded, bridge-bearing neoprene elements that prevent central threaded sleeve and attachment bolt from contacting the casting during normal operation.

2. Shock-absorbing materials: Neoprene.

3. Basis of Design: Mason Industries, Inc. Type BR.

G. Spring Isolators (Mason Spec. B): Freestanding, laterally stable, open-spring isolators.

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1. Outside Spring Diameter: Not less than 80 percent of the compressed height of the spring at rated load.

2. Minimum Additional Travel: 50 percent of the required deflection at rated load.

3. Lateral Stiffness: More than 80 percent of the rated vertical stiffness.

4. Overload Capacity: Support 200 percent of rated load, fully compressed, without deformation or failure.

5. Baseplates: Factory drilled for bolting to structure and bonded to 1/4-inch thick, elastomeric isolator pad attached to baseplate underside. Baseplates shall limit floor load to 100 psig.

6. Top Plate and Adjustment Bolt: Threaded top plate with adjustment bolt and cap screw to fasten and level equipment.

7. Basis of Design: Mason Industries, Inc. Type SFLH.

H. Restrained Spring Isolators (Mason Spec. D): Freestanding, steel, open-spring isolators with seismic restraint.

1. Housing: Steel with resilient vertical-limit stops to prevent spring extension due to wind loads or if weight is removed; factory-drilled baseplate bonded to 1/4-inch thick, elastomeric isolator pad attached to baseplate underside; and adjustable equipment mounting and leveling bolt that acts as blocking during installation.

2. Outside Spring Diameter: Not less than 80 percent of the compressed height of the spring at rated load.

3. Minimum Additional Travel: 50 percent of the required deflection at rated load.

4. Lateral Stiffness: More than 80 percent of the rated vertical stiffness.

5. Overload Capacity: Support 200 percent of rated load, fully compressed, without deformation or failure.

6. Basis of Design: Mason Industries, Inc. Type SLR.

I. Housed Spring Isolators: Housed spring isolator with integral seismic snubbers.

1. Housing: Ductile-iron or steel housing to provide all-directional seismic restraint.

2. Base: Factory drilled for bolting to structure.

3. Snubbers: Vertically adjustable to allow a maximum of 1/4-inch travel before contacting a resilient collar.

4. Basis of Design: Mason Industries, Inc. Type SSLFH.

J. Elastomeric Hangers: Double-deflection type, with molded, oil-resistant rubber or neoprene isolator elements bonded to steel housings with threaded connections for hanger rods. Color-code or otherwise identify to indicate capacity range.

1. Basis of Design: Mason Industries, Inc. Type HD & WHD.

K. Spring Hangers (Mason Spec. F): Combination coil-spring and elastomeric-insert hanger with spring and insert in compression.

1. Frame: Steel, fabricated for connection to threaded hanger rods and to allow for a maximum of 30 degrees of angular hanger-rod misalignment without binding or reducing isolation efficiency.

2. Outside Spring Diameter: Not less than 80 percent of the compressed height of the spring at rated load.

3. Minimum Additional Travel: 50 percent of the required deflection at rated load.

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4. Lateral Stiffness: More than 80 percent of the rated vertical stiffness.

5. Overload Capacity: Support 200 percent of rated load, fully compressed, without deformation or failure.

6. Elastomeric Element: Molded, oil-resistant rubber or neoprene. Steel-washer-reinforced cup to support spring and bushing projecting through bottom of frame.

7. Basis of Design: Mason Industries, Inc. Type 30N.

L. Spring Hangers with Vertical-Limit Stop (Mason Specs. G & H): Combination coil-spring and elastomeric-insert hanger with spring and insert in compression and with a vertical-limit stop.

1. Frame: Steel, fabricated for connection to threaded hanger rods and to allow for a maximum of 30 degrees of angular hanger-rod misalignment without binding or reducing isolation efficiency.

2. Outside Spring Diameter: Not less than 80 percent of the compressed height of the spring at rated load.

3. Minimum Additional Travel: 50 percent of the required deflection at rated load.

4. Lateral Stiffness: More than 80 percent of the rated vertical stiffness.

5. Overload Capacity: Support 200 percent of rated load, fully compressed, without deformation or failure.

6. Elastomeric Element: Molded, oil-resistant neoprene.

7. Adjustable Vertical Stop: Steel washer with neoprene washer "up-stop" on lower threaded rod.

8. Basis of Design: Mason Industries, Inc. Type PC30N.

2.3 DUCT AND PIPE ISOLATORS

A. General: Hanger isolators listed in above are applicable to duct and piping applications as well as suspended equipment. Additionally, items identified below are specific to duct and piping installations.

B. Thrust Limits (Mason Spec. I): Combination coil spring and elastomeric insert with spring and insert in tension, and with a load stop. Include rod and angle-iron brackets for attaching to equipment.

1. Frame: Steel, fabricated for connection to threaded rods and to allow for a maximum of

30 degrees of angular rod misalignment without binding or reducing isolation efficiency.

2. Outside Spring Diameter: Not less than 80 percent of the compressed height of the spring at rated load.

3. Minimum Additional Travel: 50 percent of the required deflection at rated load.

4. Lateral Stiffness: More than 80 percent of the rated vertical stiffness.

5. Overload Capacity: Support 200 percent of rated load, fully compressed, without deformation or failure.

6. Elastomeric Element: Molded, oil-resistant neoprene.

7. Coil Spring: Factory set and field adjustable for a maximum of 1/4-inch movement at start and stop.

8. Basis of Design: Mason Industries, Inc. Types WBD.

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C. Acoustical Wall, Ceiling or Floor Seal (Mason Spec Q): Split steel sleeve held in place by stainless steel band clamps. Isolating material between sleeve and service pipe to be closed cell neoprene sponge.

1. Basis of Design: Mason Industries, Inc. Type SWS.

2. Acceptable Option: Field fabricated seals consisting of sheet metal sleeve, stainless steel band clamps, and mineral wool or fiberglass isolating packing.

a. Seal ends of wool with silicone sealant.

D. Molded Rubber Pipe Expansion Joint (Mason Spec. O): Double sphere shaped with steel flanged end connections; peroxide or sulfur cured EPDM cover, reinforced with multiple layers of Kevlar or nylon cord; molded reinforcing ring. Unit to be designed to allow for tensile, compressive, angular and transverse movement. Units to be rated for minimum continuing operating pressures of 250psig at 170 o F and 215 psig at 250 o F.

1. Control Rods: Rods or cables and associated hardware as recommended by unit manufacturer.

2. Basis of Design: Mason Industries, Inc. – Mercer Rubber Co. Type SFDEJ.

E. Stainless Steel Hose (Mason Spec. P): Type 321 corrugated stainless steel hose with overbraid;

Male NPT ends for 2-inch and smaller, 150# flanged for 2-1/2-inch and larger.

1. Basis of Design: Mercer Rubber Co. Type BSS-GU-MN & BSS-GU-RF-150.

2. Acceptable Option: Bronze corrugated hose with overbraid; for use with copper piping systems; soldered ends.

a. Basis of Design: Mercer Rubber Co. Type BBF.

F. Molded Rubber Duct Expansion Joint: Flexible duct connectors constructed of natural rubber or synthetic liner, nylon or steel reinforced as necessary to meet operating pressures and/or vacuum conditions; 304 stainless steel bands or flanged end connections.

1. Basis of Design: Mercer Rubber Co. Duct Type Expansion Joints.

2. Acceptable Option: Expansion Joints fabricated by the ductwork supplier as acceptable pending performance standards are equal to Basis of Design.

2.4 SEISMIC RESTRAINT DEVICES

A. General: Certain items identified in paragraphs above have seismic control capabilities in addition to vibration isolation, (duct thrust restraints, restrained mounts and springs, etc.). The items identified in the following paragraphs are components specific to seismic control.

1. Base Mounted Equipment: Items identified above and herein comprise restraint systems for base mounted equipment.

2. Suspended Equipment, Piping and Ductwork Restraint Systems: Restraint systems for these items shall consist of tension and compression, (strut) components, or tension only, (cable) components. In either case, provide necessary ancillary appurtenances as required to meet seismic restrain design criteria. Each and every component is not identified herein.

a. Systems and their components shall be provided by a single manufacturer.

b. Components shall be intended and listed for use with each other, (do not mix and match components not intended for use with each other).

c. Systems may include:

1) Attachments to structure.

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2) Braces and other means of augmenting standard hanger and support assemblies.

3) Threaded rod stiffeners.

d. Restraint devices constructed of aluminum or cast iron materials are not acceptable.

B. Strut Restraint Systems: Strut components, (channel support systems) are as identified in

Section 15060, “Hangers and Supports.”

1. Basis of Design: As manufactured by B-Line Systems, Inc.

C. Restraining Cable Systems: Galvanized steel aircraft cables with end connections made of steel assemblies that swivel to final installation angle and utilize two clamping bolts for cable engagement.

1. Basis of Design: As manufactured by Mason Industries, Inc.

D. Resilient Isolation Washers and Bushings: 1-piece, molded, bridge-bearing neoprene complying with AASHTO M 251, with a flat washer face.

1. Basis of Design: Mason Industries, Inc. Types PB & HG.

E. Seismic Snubbers: Factory fabricated using welded structural-steel shapes and plates, anchor bolts, and replaceable resilient isolation washers and bushings.

1. Anchor bolts for attaching to concrete shall be seismic-rated, drill-in, and stud-wedge or female-wedge type.

2. Resilient Isolation Washers and Bushings: 1-piece, molded, bridge-bearing neoprene complying with AASHTO M 251.

3. Basis of Design: Mason Industries, Inc. Types Z-1225 & Z-1011.

F. Anchor Bolts: Seismic-rated, drill-in, and stud-wedge or female-wedge type. Select anchor bolts with strength required for anchor and as tested according to ASTM E 488/E 488M.

1. Basis of Design: Mason Industries, Inc. Types SAS & SAB.

2.5 FACTORY FINISHES

A. Manufacturer's standard prime coat finish ready for field painting.

B. Finish: Manufacturer's standard paint applied to factory-assembled and -tested equipment before shipping.

1. Powder coating on springs and housings.

2. All hardware shall be electro-galvanized. Hot dip galvanized metal components for exterior use.

3. Baked enamel for metal components on isolators for interior use.

4. Color code or otherwise mark vibration isolation and seismic control devices to indicate capacity range.

PART 3 - EXECUTION

3.1 EXAMINATION

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A. Examine areas and equipment to receive vibration isolation and seismic-control devices for compliance with requirements, installation tolerances, and other conditions affecting performance.

B. Examine roughing-in of reinforcement and cast-in-place anchors to verify actual locations before installation.

C. Proceed with installation only after unsatisfactory conditions have been corrected.

3.2 EQUIPMENT INSTALLATION, GENERAL

A. Install roof curbs, equipment supports, and roof penetrations as specified in Division 7 Section

"Roof Accessories."

B. Concrete Bases: Anchor equipment to concrete base according to supported equipment manufacturer's written instructions for seismic codes at Project site.

C. Support Equipment: Install isolators on support equipment that is part of an isolated system.

1. Suspended Support Equipment: Types HD & WHD.

3.3 DUCT AND PIPING SYSTEMS INSTALLATION

A. General: Piping and ductwork systems shall be supported in accordance with their respective

Sections as well as the requirements of Section 230529, “Hangers and Supports.” In addition to those requirements, described herein are requirements to address vibration and seismic forces.

B. Connections to Equipment, General: Piping and Duct connections to isolated pieces of

Mechanical equipment shall include the following means of limiting vibration transmissions to the piping and ductwork.

1. Equipment Connections: Install duct and pipe isolators at the inlet and outlet connections to each piece of isolated equipment. Exact locations of isolators as detailed on the

Drawings.

a. Types SFDEJ, BSS-GU-MN, BSS-GU-RF-150, BBF & Duct Type.

2. Suspended Piping and Ductwork Either Side: Isolate pipe and duct runs leading to and/or away from each piece of isolated equipment for a distance of 50 feet. Pipe and duct support isolator types to match those used on the isolated equipment. Minimum static deflection to be one-half that of the equipment isolator.

a. Ducts and pipes serving equipment isolated by elastomeric pads or mounts;

1) Seismic & Non Seismic Applications: Types HD & WHD.

b. Ducts and pipes serving equipment isolated by springs;

1) Seismic Application: Type PC30N.

2) Non-Seismic Application: Type 30N.

3. Wall, Floor and Hard Ceiling Penetrations: Where services leading to and/or away from isolated equipment penetrate walls, floors and/or hard ceilings within 50 feet of the equipment, the wall and/or floor penetrations shall be acoustically isolated.

a. Type SWS.

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1) Exception: Where walls and/or floors penetrated are fire rated, provide a sleeve and appropriate fire stopping in lieu of this acoustical isolator. Fire

Stopping is specified in Division 7.

4. Riser Isolation: Isolation of vertical riser-through-floor penetrations within 50 feet of isolated equipment shall be accomplished via using pairs of isolators which transmit riser load from a heavy duty riser clamp, (welded to the pipe) or welded attachments.

a. Risers servicing equipment isolated by elastomeric pads or mounts;

1) Types W & SW with a steel plate between the isolator and riser clamp.

b. Risers servicing equipment isolated by springs;

1) Type SLR.

5. Base of Riser and Horizontal Floor Supported Services: Isolation of floor supported piping and ductwork within 50 feet of isolated equipment shall be accomplished via using pairs of isolators which transmit load from a service –supporting cross member. Pipe and duct support isolator types to match those used on the isolated equipment. Minimum static deflection to also match that of the equipment isolator.

a. Ducts and pipes serving equipment isolated by elastomeric pads or mounts;

1) Types HD & WHD.

b. Ducts and pipes serving equipment isolated by springs;

1) Type SLR.

C. Duct Connections to Fans: Install a pair of thrust restraints at duct connections the following fans. Thrust restraints shall bridge flexible duct connectors and shall be installed along either side of the centerline of the thrust.

1. All suspended fans.

a. Type WBD.

2. Base mounted fans which generate more than 4-inches of static pressure.

a. Type WBD.

3. Exception: Thrust restraints are not required where thrust forces do not exceed 10% of the equipment weight.

D. Common Support Requirements: Where piping is intended to be installed on a common, (trapeze) rack, the following shall apply;

1. Do not install isolated and non-isolated services on the same rack.

2. Rack isolation shall be of a type and meet the requirements of the most stringent isolation

3. Services shall be clipped on to the rack, (or attached via guides if the plans specifically call for this). Neoprene isolators shall be installed between the pipe and the rack/clip.

3.4 SEISMIC CONTROLS INSTALLATION

A. General: Install seismic bracing to limit movement of equipment, piping and ductwork in all directions. Provide stiffeners or otherwise augment standard supports at brace locations to accommodate seismic forces imposed.

1. Threaded hanger rod at brace locations shall be capable of supporting both standard working loads as well as seismic tensile and compressive loads.

a. Where rod length exceeds allowable unbraced rod length, provide standard 12 gauge strut rod stiffeners and clamp reinforcements over the entire length of the rod.

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b. The maximum allowable unbraced length or rods shall not exceed 18-inches for

3/8-inch rod and 24-inches for ½ through 7/8-inch rod. Installing contractor to verify maximum unbraced rod lengths allowable via calculations.

B. Equipment Controls, General: Certain seismic control requirements are satisfied by components identified in the vibration isolation schedule at the end of this Section, (limit stops and housings). The installations contained herein are required in addition to those items.

1. Controls must not overload building structural components. Attach controls to major building structural elements such as beams, columns and concrete floors. Avoid attaching to open joints and lighter weight elements.

C. Base-Mounted Non-Isolated Equipment: Install seismic controls on non-isolated equipment which is not specifically addressed by the “Support Equipment” paragraph above.

1. Option #1: Equipment bolt holes are adequate to resist seismic forces;

a. Install an epoxy compound in the void space between each bolt and bolt hole, or

b. weld a steel washer, centered over each bolt hole to limit bolt movement, or

c. Install a neoprene grommet around each bolt, Type HG.

2. Option #2: Equipment bolt holes are adequate to resist seismic forces;

a. Weld or bolt angles onto the side of the equipment base, minimum (2) per side.

b. Bolt each angle to structure (2) places.

3. Option #3: Equipment bolt holes are adequate to resist seismic forces, no tensile loading or overturning moment present, (small loads). Controls do not need to be attached to the equipment.

a. Bolt angles to structure, minimum (2) per side.

b. Install a neoprene pad between each angle and the equipment, Type W or SW.

D. Suspended Vibration Isolated Equipment: Brace equipment at a minimum of (4) points using cable restraints.

1. Install cable with ½-inch of slack to accommodate isolator motion.

2. Provide stiffeners on hanger rods if calculation dictate.

E. Suspended Non Isolated Equipment: Non-isolated equipment which is not specifically addressed by the “Support Equipment” paragraph above shall be restrained with taut cable or strut type restraint systems, installed at a minimum of (4) places.

1. Exception: In-line VAV boxes which are “hard ducted” may be treated simply as ductwork.

2. Provide stiffeners on hanger rods if calculations dictate.

F. Piping and Ductwork Controls, General: Install sway bracing on pipe and duct systems.

1. Bracing to consist of tension only cable systems where piping or ductwork includes vibration isolated hangers.

a. Install cable with ½-inch of slack to accommodate isolator motion.

b. Provide stiffeners on hanger rods if calculation dictate.

2. Where piping or ductwork does not include vibration isolated hangers and supports, tension only cable or tension-and-compression strut systems may be used.

a. Install cable systems taut.

b. Provide stiffeners on hanger rods if calculation dictate.

3. Multiple Piping Application: At trapeze anchor locations, shackle piping to trapeze.

4. Cable Systems, General: Install cables so they do not bend across sharp edges of adjacent equipment or building structure.

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5. Strut Systems, General: Install steel angles or channel, sized to prevent buckling, clamped with ductile-iron clamps to hanger rods for trapeze and individual pipe hangers.

G. Piping and Ductwork General Brace Location Requirements: Each straight run of piping or ductwork shall include a minimum of (2) transverse and (1) longitudinal brace.

1. If the overall length of the run exceeds maximum brace spacing identified below, than additional bracing must be installed.

2. Transverse brace locations shall include the ends of each straight run.

3. A transverse brace within 2-feet of a 90 o bend may meet the spacing requirements of a longitudinal brace in the adjacent 90 o section to the order of half the maximum allowable longitudinal spacing minus 2 feet.

4. Install a transverse brace within 2-feet of each pipe drop or rise to an equipment connection.

5. Install a transverse brace within 2 times the duct width of each drop or rise to an equipment connection.

6. Exceptions: Bracing of pipe and ductwork systems is not required under the following circumstances. These exceptions do not apply to natural gas, propane, fuel oil, toxic or corrosive gasses.

a. Piping suspended by individual hangers where the distance from top-of-pipe to the underside of supporting structure is 12-inches or less.

b. Piping in mechanical equipment rooms which is smaller than 1-1/4-inch diameter.

c. Piping in all other areas which is smaller than 2-1/2-inch diameter.

d. Ducts suspended by individual hangers where the distance from top-of-duct to the underside of supporting structure is 12-inches or less.

e. Ducts which have a cross-sectional area less than 6 square feet.

H. Copper and Steel Piping Systems (Welded, Soldered, Brazed, Grooved, or Threaded): Install bracing in accordance with the following maximum spacing:

1. Transverse Brace Spacing: 50 feet.

2. Longitudinal Braces: Install at 80 foot intervals, maximum.

I. Plastic Piping Systems (Cemented or Fused): Install bracing in accordance with the following maximum spacing:

1. Transverse Brace Spacing: 25 feet.

2. Longitudinal Braces: Install at 40 foot intervals, maximum.

J. Cast Iron Piping Systems (Hubless): Install bracing in accordance with the following maximum spacing:

1. Transverse Brace Spacing: 25 feet.

2. Longitudinal Braces: Install at 40 foot intervals, maximum.

K. Ductwork: Install bracing in accordance with the following maximum spacing:

1. Transverse Brace Spacing: 40 feet.

2. Longitudinal Braces: Install at 80 foot intervals, maximum.

3.5 FIELD QUALITY CONTROL

A. Testing: Perform the following field quality-control testing:

1. Isolator seismic-restraint clearance.

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2. Isolator deflection.

3. Snubber minimum clearances.

3.6 ADJUSTING

A. Adjust isolators after piping systems have been filled and equipment is at operating weight.

B. Adjust limit stops on restrained spring isolators to mount equipment at normal operating height.

After equipment installation is complete, adjust limit stops so they are out of contact during normal operation.

C. Attach thrust limits at centerline of thrust and adjust to a maximum of 1/4-inch movement during start and stop.

D. Adjust active height of spring isolators.

E. Torque anchor bolts according to equipment manufacturer's written recommendations to resist seismic forces.

F. Adjust seismic restraints to permit free movement of equipment within normal mode of operation.

G. Adjust snubbers according to manufacturer's written recommendations.

3.7 CLEANING

A. After completing equipment installation, inspect vibration isolation and seismic-control devices.

Remove paint splatters and other spots, dirt, and debris.

END OF SECTION 230548

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