230541 NOISE AND VIBRATION CONTROL seismic.pdf

UPGRADE EMERGENCY POWER IN BUILDING 138

VAMC, MARION, IN PROJECT: 610-16-104

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SECTION 23 05 41

NOISE AND VIBRATION CONTROL FOR HVAC PIPING AND EQUIPMENT

PART 1 - GENERAL

1.1 DESCRIPTION

A. This section specifies the application of noise con trol measures, seismic restraint for equipment, and vibration cont rol techniques to rotating equipment and parts including pumps, fans, motors, and pipe.

B. A complete listing of all common acronyms and abbre viations are included in Section 23 05 11, COMMON WORK RESULTS F OR HVAC.

C. Noise criteria, seismic restraints for equipment , vibration tolerance and vibration isolation for HVAC and plumbing work.

1.2 RELATED WORK

A. Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA an d SAMPLES.

B. Section 23 05 11, COMMON WORK RESULTS FOR HVAC.

C. Section 23 31 00, HVAC DUCTS and CASINGS.

1.3 QUALITY ASSURANCE

A. Refer to article, QUALITY ASSURANCE in specifica tion Section 23 05 11, COMMON WORK RESULTS FOR HVAC and STEAM GENERATION.

B. Noise Criteria:

1. Noise levels in all 8 octave bands due to equipm ent and duct systems shall not exceed following NC levels:

TYPE OF ROOM NC LEVEL

Electric Equipment Rooms 50

2. For equipment which has no sound power ratings s cheduled on the plans, the contractor shall select equipment such t hat the fore-going noise criteria, local ordinance noise levels, and OSHA re-quirements are not exceeded. Selection procedure sh all be in accordance with ASHRAE Fundamentals Handbook, Chapt er 8, Sound and

Vibration.

3. An allowance, not to exceed 5db, may be added to the measured value to compensate for the variation of the room attenua ting effect between room test condition prior to occupancy and design condition after occupancy which may include the addition of s ound absorbing material, such as, furniture. This allowance shall not be taken after occupancy. The room attenuating effect is def ined as the

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23 05 41 - 2 difference between sound power level emitted to roo m and sound pressure level in room.

4. In absence of specified measurement requirements , measure equipment noise levels three feet from equipment and at an el evation of maxi-mum noise generation.

C. Seismic Restraint Requirements:

1. Equipment:

a. All mechanical equipment not supported with isol ators external to the unit shall be securely anchored to the structur e. Such mechanical equipment shall be properly supported to resist a horizontal force of 20 percent of the weight of the equipment furnished.

b. All mechanical equipment mounted on vibration is olators shall be provided with seismic restraints capable of resisti ng a horizontal force of 20 percent of the weight of the equipment furnished.

2. Piping: Refer to specification Section 23 05 10, COMMON WORK RESULTS

FOR HVAC.

3. Ductwork: Refer to specification Section 23 31 0 0, HVAC DUCTS AND

CASINGS.

D. Allowable Vibration Tolerances for Rotating, Non -reciprocating Equip-ment: Not to exceed a self-excited vibration maximu m velocity of 5 mm per second (0.20 inch per second) RMS, filter in, w hen measured with a vibration meter on bearing caps of machine in verti cal, horizontal and axial directions or measured at equipment mounting feet if bearings are concealed. Measurements for internally isolated fan s and motors may be made at the mounting feet.

1.4 SUBMITTALS

A. Submit in accordance with specification Section 01 33 23, SHOP

DRAWINGS, PRODUCT DATA, and SAMPLES.

B. Manufacturer's Literature and Data:

1. Vibration isolators:

a. Floor mountings

b. Hangers

c. Snubbers

d. Thrust restraints

2. Bases.

3. Seismic restraint provisions and bolting.//

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4. Acoustical enclosures.

C. Isolator manufacturer shall furnish with submitt al load calculations for selection of isolators, including supplemental bases, based on lowest operating speed of equipment supported.

D. Seismic Requirements: Submittals are required fo r all equipment anchors, supports and seismic restraints. Submittal s shall include weights, dimensions, standard connections, and manu facturer's certification that all specified equipment will wit hstand seismic

Lateral Force requirements as shown on drawings.

1.5 APPLICABLE PUBLICATIONS

A. The publications listed below form a part of thi s specification to the extent referenced. The publications are referenced in the text by the basic designation only.

B. American Society of Heating, Refrigerating and A ir-Conditioning

Engineers, Inc. (ASHRAE):

Handbook 2017...........Fundamentals Handbook, Chap ter 8, Sound and

Vibration

C. American Society for Testing and Materials (ASTM ):

A123/A123M-2017.........Standard Specification for Zinc (Hot-Dip

Galvanized) Coatings on Iron and Steel Products

A307-2016...............Standard Specification for Carbon Steel Bolts and Studs, 60,000 PSI Tensile Strength

D2240-05(2010)..........Standard Test Method for Ru bber Property -

Durometer Hardness

D. Manufacturers Standardization (MSS):

SP-58-2018..............Pipe Hangers and Supports-M aterials, Design and

Manufacture

E. Occupational Safety and Health Administration (O SHA):

29 CFR 1960.95..........Occupational Noise Exposure

F. American Society of Civil Engineers (ASCE):

ASCE 7-2017.............Minimum Design Loads for Bu ildings and Other

Structures.

G. American National Standards Institute / Sheet Me tal and Air

Conditioning Contractor’s National Association (ANS I/SMACNA):

001-2008................Seismic Restraint Manual: G uidelines for

Mechanical Systems, 3rd Edition.

G. International Code Council (ICC):

IBC 2018................International Building Code .

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I. Department of Veterans Affairs (VA):

H-18-8 2019.............Seismic Design Requirements .

PART 2 - PRODUCTS

2.1 GENERAL REQUIREMENTS

A. Type of isolator, base, and minimum static defle ction shall be as required for each specific equipment application as recommended by isolator or equipment manufacturer but subject to m inimum requirements indicated herein and in the schedule on the drawing s.

B. Elastometric Isolators shall comply with ASTM D2 240 and be oil resistant neoprene with a maximum stiffness of 60 d urometer and have a straight-line deflection curve.

C. Exposure to weather: Isolator housings shall be either hot dipped galvanized or powder coated to ASTM B117 salt spray testing standards.

Springs shall be powder coated or electro galvanize d. All hardware shall be electro galvanized. In addition provide l imit stops to resist wind velocity. Velocity pressure established by win d shall be calculated in accordance with section 1609 of the I nternational

Building Code. A minimum wind velocity of 75 mph s hall be employed.

D. Uniform Loading: Select and locate isolators to produce uniform loading and deflection even when equipment weight is not ev enly distributed.

E. Color code isolators by type and size for easy i dentification of capacity.

2.2 SEISMIC RESTRAINT REQUIREMENTS FOR EQUIPMENTS

A. Bolt pad mounted equipment, without vibration is olators, to the floor or other support using ASTM A307 standard bolting m aterial.

B. Floor mounted equipment, with vibration Isolator s: Type SS. Where Type

N isolators are used provide channel frame base hor izontal restraints bolted to the floor, or other support, on all sides of the equipment

Size and material required for the base shall be as recommended by the isolator manufacturer.

C. On all sides of suspended equipment, provide bra cing for rigid supports and provide restraints for resiliently supported eq uipment.

2.2 VIBRATION ISOLATORS

A. Floor Mountings:

1. Double Deflection Neoprene (Type N): Shall inclu de neoprene covered steel support plated (top and bottom), friction pad s, and necessary bolt holes.

2. Captive Spring Mount for Seismic Restraint (Type SS):

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a. Design mounts to resiliently resist seismic forc es in all direc-tions. Snubbing shall take place in all modes with adjustment to limit upward, downward, and horizontal travel to a maximum of 6 mm (1/4-inch) before contacting snubbers. Mountings shall have a minimum rating of one G coefficient of gravity as c alculated and certified by a registered structural engineer.

b. All mountings shall have leveling bolts that mus t be rigidly bolted to the equipment. Spring diameters shall be no less than

0.8 of the compressed height of the spring at rated load. Springs shall have a minimum additional travel to solid equ al to 50 percent of the rated deflection. Mountings shall ha ve ports for spring inspection. Provide an all directional neopr ene cushion collar around the equipment bolt.

3. Spring Isolators with Vertical Limit Stops (Type SP): Similar to spring isolators noted above, except include a vert ical limit stop to limit upward travel if weight is removed and als o to reduce movement and spring extension due to wind loads. Pr ovide clearance around restraining bolts to prevent mechanical shor t circuiting.

Isolators shall have a minimum seismic rating of on e G.

4. Seismic Pad (Type DS): Pads shall be natural rub ber / neoprene waffle with steel top plate and drilled for an anch or bolt. Washers and bushings shall be reinforced duck and neoprene. Size pads for a maximum load of 345 kPa (50 pounds per square inch) .

B. Hangers: Shall be combination neoprene and sprin gs unless otherwise noted and shall allow for expansion of pipe.

1. Combination Neoprene and Spring (Type H): Vibrat ion hanger shall contain a spring and double deflection neoprene ele ment in series.

Spring shall have a diameter not less than 0.8 of c ompressed oper-ating spring height. Spring shall have a minimum ad ditional travel of 50 percent between design height and solid heigh t. Spring shall permit a 15 degree angular misalignment without rub bing on hanger box.

2. Spring Position Hanger (Type HP): Similar to com bination neoprene and spring hanger except hanger shall hold piping a t a fixed elevation during installation and include a seconda ry adjustment feature to transfer load to spring while maintainin g same position.

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3. Neoprene (Type HN): Vibration hanger shall conta in a double deflection type neoprene isolation element. Hanger rod shall be separated from contact with hanger bracket by a neo prene grommet.

4. Spring (Type HS): Vibration hanger shall contain a coiled steel spring in series with a neoprene grommet. Spring sh all have a diameter not less than 0.8 of compressed operating spring height.

Spring shall have a minimum additional travel of 50 percent between design height and solid height. Spring shall permit a 15 degree angular misalignment without rubbing on hanger box.

5. Hanger supports for piping 50 mm (2 inches) and larger shall have a pointer and scale deflection indicator.

6. Hangers used in seismic applications shall be pr ovided with a neoprene and steel rebound washer installed ¼’ clea r of bottom of hanger housing in operation to prevent spring from excessive upward travel

C. Snubbers: Each spring mounted base shall have a minimum of four all-directional or eight two directional (two per side) seismic snubbers that are double acting. Elastomeric materials shall be shock absorbent neoprene bridge quality bearing pads, maximum 60 du rometer, replaceable and have a minimum thickness of 6 mm (1/4 inch). Ai r gap between hard and resilient material shall be not less than 3 mm (1/8 inch) nor more than 6 mm (1/4 inch). Restraints shall be capable o f withstanding design load without permanent deformation.

D. Thrust Restraints (Type THR): Restraints shall p rovide a spring element contained in a steel frame with neoprene pads at ea ch end attachment.

Restraints shall have factory preset thrust and be field adjustable to allow a maximum movement of 6 mm (1/4 inch) when th e fan starts and stops. Restraint assemblies shall include rods, ang le brackets and other hardware for field installation.

2.3 BASES

A. Rails (Type R): Design rails with isolator brack ets to reduce mounting height of equipment and cradle machines having legs or bases that do not require a complete supplementary base. To assur e adequate stiffness, height of members shall be a minimum of 1/12 of longest base dimension but not less than 100 mm (4 inches). Wher e rails are used with neoprene mounts for small fans or close couple d pumps, extend rails to compensate overhang of housing.

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B. Integral Structural Steel Base (Type B): Design base with isolator brackets to reduce mounting height of equipment whi ch require a complete supplementary rigid base. To assure adequa te stiffness, height of members shall be a minimum of 1/12 of longest ba se dimension, but not less than 100 mm (four inches).

C. Inertia Base (Type I): Base shall be a reinforce d concrete inertia base. Pour concrete into a welded steel channel fra me, incorporating prelocated equipment anchor bolts and pipe sleeves. Level the concrete to provide a smooth uniform bearing surface for equ ipment mounting.

Provide grout under uneven supports. Channel depth shall be a minimum of 1/12 of longest dimension of base but not less t han 150 mm (six inches). Form shall include 13-mm (1/2-inch) reinfo rcing bars welded in place on minimum of 203 mm (eight inch) centers run ning both ways in a layer 40 mm (1-1/2 inches) above bottom. Use height saving brackets in all mounting locations. Weight of inertia base shal l be equal to or greater than weight of equipment supported to provi de a maximum peak-to-peak displacement of 2 mm (1/16 inch).

D. Curb Mounted Isolation Base (Type CB): Fabricate from aluminum to fit on top of standard curb with overlap to allow water run-off and have wind and water seals which shall not interfere with spring action.

Provide resilient snubbers with 6 mm (1/4 inch) cle arance for wind resistance. Top and bottom bearing surfaces shall h ave sponge type weather seals. Integral spring isolators shall comp ly with Spring

Isolator (Type SS) requirements.

2.4 SOUND ATTENUATING UNITS

Refer to specification Section 23 31 00, HVAC DUCT S and CASINGS and 23

33 19 DUCT SILENCERS.

PART 3 - EXECUTION

3.1 INSTALLATION

A. Vibration Isolation:

1. No metal-to-metal contact will be permitted betw een fixed and floating parts.

2. Connections to Equipment: Allow for deflections equal to or greater than equipment deflections. Electrical, drain, pipi ng connections, and other items made to rotating or reciprocating e quipment (pumps, compressors, etc.) which rests on vibration isolato rs, shall be isolated from building structure for first three ha ngers or supports with a deflection equal to that used on the corresp onding equipment.

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3. Common Foundation: Mount each electric motor on same foundation as driven machine. Hold driving motor and driven machi ne in positive rigid alignment with provision for adjusting motor alignment and belt tension. Bases shall be level throughout lengt h and width.

Provide shims to facilitate pipe connections, level ing, and bolting.

4. Provide heat shields where elastomers are subjec t to temperatures over 38 degrees C (l00 degrees F).

5. Extend bases for pipe elbow supports at discharg e and suction connections at pumps. Pipe elbow supports shall not short circuit pump vibration to structure.

6. Non-rotating equipment such as heat exchangers a nd convertors shall be mounted on isolation units having the same stati c deflection as the isolation hangers or support of the pipe connec ted to the equipment.

B. Inspection and Adjustments: Check for vibration and noise transmission through connections, piping, ductwork, foundations, and walls. Adjust, repair, or replace isolators as required to reduce vibration and noise transmissions to specified levels.

3.2 ADJUSTING

A. Adjust vibration isolators after piping systems are filled and equipment is at operating weight.

B. Adjust limit stops on restrained spring isolator s to mount equipment at normal operating height. After equipment installati on is complete, adjust limit stops so they are out of contact durin g normal operation.

C. Attach thrust limits at centerline of thrust and adjust to a maximum of

1/4inch (6-mm) movement during start and stop.

D. Adjust active height of spring isolators.

E. Adjust snubbers according to manufacturer's reco mmendations.

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

G. Torque anchor bolts according to equipment manuf acturer's recommendations to resist seismic forces.

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SELECTION GUIDE FOR VIBRATION ISOLATORS

EQUIPMENT ON GRADE 20FT FLOOR SPAN 30FT FLOOR SPAN 40FT FLOOR SPAN 50FT FLOOR SPAN

BASE

TYPE

ISOL

TYPE

MIN

DEFL

BASE

TYPE

ISOL

TYPE

MIN

DEFL

BASE

TYPE

ISOL

TYPE

MIN

DEFL

BASE

TYPE

ISOL

TYPE

MIN

DEFL

BASE

TYPE

ISOL

TYPE

MIN

DEFL

PUMPS

CLOSE

COUPLED

UP TO

1-1/2

HP

--- --- --- --- DS --- --- DS --- --- DS --- --- DS ---

2 HP &

OVER

--- --- --- I SS 0.8 I SS 1.5 I SS 1.5 I SS 2.0

BASE

MOUNTED

UP TO

10 HP

--- --- --- --- DS --- --- DS --- --- DS --- --- DS ---

INTERNAL COMBUSTION ENGINES

125 HP & OVER I N 0.75 I N 1.5 I SS 2.5 I SS 3.5 I SS 4.5

AIR HANDLING UNIT PACKAGES

FLOOR MOUNTED:

UP THRU 5 HP --- DS --- --- SS 1.0 --- SS 1.0 --- S S 1.0 --- SS 1.0

HEAT PUMPS

ALL --- SS 0.75 --- SS 0.75 --- SS 0.75 CB SS 1.5 - -- --- NA

CONDENSING UNITS

ALL --- SS 0.25 --- SS 0.75 --- SS 1.5 CB SS 1.5 -- - --- NA

IN-LINE CENTRIFUGAL AND VANE AXIAL FANS, FLOOR MOUNTED: (APR 9)

UP THRU 50 HP:

UP TO 300 RPM --- DS --- R SS 2.5 R SS 2.5 R SS 2.5 R SS 3.5

301 - 500 RPM --- DS --- R SS 2.0 R SS 2.0 R SS 2.5 R SS 2.5

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EQUIPMENT ON GRADE 20FT FLOOR SPAN 30FT FLOOR SPAN 40FT FLOOR SPAN 50FT FLOOR SPAN

BASE

TYPE

ISOL

TYPE

MIN

DEFL

BASE

TYPE

ISOL

TYPE

MIN

DEFL

BASE

TYPE

ISOL

TYPE

MIN

DEFL

BASE

TYPE

ISOL

TYPE

MIN

DEFL

BASE

TYPE

ISOL

TYPE

MIN

DEFL

501 - & OVER --- DS --- --- SS 1.0 --- SS 1.0 R SS 2.0 R SS 2.5