Selection Guide for Vibration Isolation of HVAC Equipment

Transcription

1 Selection Guide for Vibration Isolation of HV

2 KINETIS NOISE ONTROL, IN., is recognized as the major producer of products and systems for the control of noise and vibration. The ompany markets products under the trade name KINETIS. KINETIS products and engineered systems have been incorporated throughout major industrial and commercial buildings in the United States, anada, Europe, ustralia, and the Far East. Kinetics Noise ontrol s national headquarters and manufacturing facilities are located in Dublin, Ohio, in a 60,000 sq. ft. (55 m) facility. The ompany provides products, systems, and solutions to everyday problems and for complex applications requiring noise and vibration control analysis. y using the Kinetics Selection Guide contained in this bulletin, proper isolation can be specified by type and deflection to obtain optimum effectiveness of the isolators. y specifying deflection rather than theoretical isolation efficiency, performance can be assured and can be readily verified in the field. Kinetics engineering and testing facilities are available at all times to assure that each product is tailored to meet project specifications and field conditions. Its staff of professionals welcomes the opportunity to assist in selecting and specifying the company s products and systems. Kinetics provides certified engineering drawings when requested for all products to assure compliance with project specifications. Vibration and vibrationinduced noise, major sources of occupant complaint, have steadily increased in today s modern buildings. The problems have been compounded by lighter weight construction and by the positioning of equipment in penthouses or intermediate level mechanical rooms. Not only is the physical vibration in the structure disturbing, but noise which is regenerated by the structural movement may be heard in other remote sections of the structure. Effectiveness of vibration isolators in bringing about vibration reduction is indicated by the transmissibility of the system. typical transmissibility curve is shown for vibrating equipment supported on isolators. When the isolated system is excited at its natural frequency, the system will be in resonance, and exciting forces will be amplified rather than reduced. It is desirable to select isolators with a natural frequency as far below the equipment operating speed as possible to achieve the highest degree of vibration control. The Theoretical Isolation Efficiency shown on the transmissibility curve assumes the isolators are located on a rigid floor. This rigidity seldom occurs in abovegrade applications. In practice, considerable building deflection can occur, which may reduce the effectiveness of the vibration isolators. Vibration isolators must be selected to compensate for the floor deflection. Longer spans also allow the structure to be more flexible, permitting the building to be more easily set into motion. With the aid of the Kinetics Selection Guide, building spans, equipment operating speeds, equipment horsepower, damping, and other factors have been taken into consideration. Typical transmissibility curve for an isolated system y specifying Deflection rather than isolation efficiency, transmissibility, or other theoretical parameters, the consulting engineer can compensate for floor deflection and building resonances by selecting isolators which are satisfactory to provide minimum vibration transmission and which have more deflection than the supporting floor. y stating that all isolators and equipment bases shall be of the same manufacturer and shall be supplied to the mechanical contractor, the consulting engineer has placed the responsibility on a single source who will be concerned with the vibration transmission from all mechanical equipment in the building, rather than only those which they supply. When the specifier permits equipment suppliers to provide appropriate isolators, which are not manufactured under Kinetics high standards, he does not assure a satisfactory job, since different brands of isolators may be furnished and no one supplier carries the full responsibility for a building free of vibration and noise as specified. To apply the information from the Selection Guide, base type, isolator type, and minimum deflection columns are added to the equipment schedule, and the isolator specifications are incorporated into the specifications for the project. Then, for each piece of mechanical equipment, base type, isolator type, and minimum deflection are entered, as tabulated in the Selection Guide. The Kinetics Selection Guide is available in digital format so consulting engineers can select vibration isolators with the aid of their computer. Digital copies are available through Kinetics representatives, on the Kinetics Noise ontrol website or by contacting Kinetics directly. Vibration Isolation Vibration Isolation Pump Number GPM ase Minimum Deflection ir Unit Number rea FM (cmm) Wheel Diameter ase Minimum Deflection P P P P Split ase lose oupled End Suction End Suction 6.5 ().5 () H H H H RM0 RM095 RM0 RM () (0) (06) () 8 (5) 0 (508) 6 (9) (60) ().5 ().5 ()

3 Specifications The isolator or base selected for a particular application depends on the required deflection, life, cost, and compatibility with associated structures and shall be manufactured by Kinetics Noise ontrol, Inc. Dublin, Ohio, as follows: s and : Rubber isolators are available in pad (type I) and molded (type ) configurations. Pads are used in single or multiple layers. Molded isolators come in a range of 0 to 0 durometer (a measure of stiffness). Material in excess of 0 durometer is usually ineffective as an isolator. s are designed for up to mm deflection, but are used where 8 mm or less deflection is required. Solid rubber and composite fabric and rubber pads are also available. They provide high load capacities with small deflection and are used as noise barriers under columns and for pipe supports. These pad types work well only when they are properly loaded and the mass load is evenly distributed over the entire pad surface. Metal loading plates can be used for this purpose. : Glass fiber with elastic coating (type ). This type of isolation pad is precompressed molded fiberglass pads individually coated with a flexible, moistureimpervious elastomeric membrane. Natural frequency of fiberglass vibration isolators should be essentially constant for the operating load range of the supported equipment. Mass load is evenly distributed over the entire pad surface. Metal loading plates can be used for this purpose. s and : Steel springs are the most popular and versatile isolators for HV applications because they are available for almost any deflection and have a virtually unlimited life. Spring isolators may have a robber acoustical barrier to reduce transmission of highfrequency vibration and noise that can migrate down the steel spring coil. They should be corrosionprotect if installed outdoors or in a corrosive environment. The basic types include the following: : Open spring isolators (type ) consist of top and bottom load plates with adjustment bolts for leveling equipment. Springs should be designed with a horizontal stiffness of at least 80% of the vertical stiffness to ensure stability. Similarly, the springs should have a minimum ratio of 0.8 for the diameter divided by the deflected spring height. losed mounts or housed spring isolators consist of two telescoping housings separated by a resilient material. These provide lateral snubbing and some vertical damping of equipment movement, bill do not limit the vertical movement. are should be taken selection and installation to minimize binding and shortcircuiting. s and 6: ir springs can be designed for any frequency, but are economical only in applications with natural frequencies of. Hz or less (50 mm or greater deflection). They do not transmit high frequency noise and are often used to replace highdeflection springs on problem jobs (e.g., large transformers on upperfloor installations). constant air supply (an air compressor with an air dryer) and leveling valves are typically required. : Isolation hangers (types and ) are used for suspended pipe and equipment and have rubber, springs, or a combination of spring and rubber elements. riteria should be similar to open spring isolators, though lateral stability is less important. Where support rod angular misalignment is a concern, use hangers that have sufficient clearance and/or incorporate rubber bushings to prevent the rod from touching the housing. Swivel or traveler arrangements may be necessary for connections to piping systems subject to large thermal movements. Precompressed spring hangers incorporate some means of precompression or preloading of the isolator spring to minimize movement of the isolated equipment or system. These are typically used on piping systems that can change mass substantially between installation and operation. 5: Thrust restraints (type 5) are similar 0 spring hangers or isolators and are installed in pairs to resist the thrust caused by air pressure. These are typically sized 0 limit lateral movement 06. mm or less. ase : Direct isolation (type ) is used when equipment is unitary and rigid and does not require additional support. Direct isolation can be used with large chillers, some fans, packaged airhandling units, and aircooled condensers. If there is any doubt that the equipment can be supported directly on isolators, use structural bases (type ) or inertia bases (type ), or consult the equipment manufacturer. : Restrained spring isolators (type ) have holddown bolts to limit vertical as well as horizontal movement. They are used with (a) equipment with large variations in mass (e.g., boilers, chillers. cooling towers) to restrict movement and prevent strain on piping when water is removed, and (b) outdoor equipment, such as condensing units and cooling towers, to prevent excessive movement due to wind loads. Spring criteria should be the same as open spring isolators, and restraints should have adequate clearance so that they are activated only when a temporary restraint is needed.

4 ase : Structural bases (type ) are used where equipment cannot be support at individual locations and/or where some means is necessary to maintain alignment of component pans in equipment. These bases can be used with spring or rubber isolators (types and ) and should have enough rigidity to resist all starting and operating forces without supplemental holddown devices. ases are made in rectangular configurations using structural members with a depth equal to onetenth the longest span between isolators. Typical base depth is between 00 and 00 mm, except where structural or alignment considerations dictate otherwise. Structural rails (type ) are used to support equipment that does not require a unitary base or where the isolators are outside the equipment and the rails act as a cradle. Structural rails can be used with spring or rubber isolators and should be rigid enough to support the equipment without flexing. Usual practice is to use structural members with a depth onetenth of the longest span between isolators, typically between 00 and 00 mm, except where structural considerations dictate otherwise. ase : oncrete bases (type ) are used where the supported equipment requires a rigid support (e.g., flexiblecoupled pumps) or excess heaving motion may occur with spring isolators. They consist of a steel pouring form usually with weldedin rein forcing bars, provision for equipment holddown, and isolator brackets. Like structural bases, concrete bases should be sized to support piping elbow supports, rectangular or Tshaped, and for rigidity, have a depth equal to onetenth the longest span between isolators. ase depth is typically between 50 and 00 mm unless additional depth is specifically required for mass, rigidity, or component alignment. ase D: urb isolation systems (type D) are specifically designed for curbsupported rooftop equipment and have spring isolation with a watertight, and sometimes airtight, assembly. Rooftop rails consist of upper and lower frames separated by nonadjustable springs and rest on top of architectural roof curbs. Isolation curbs incorporate the roof curb into their design as well. oth kinds are designed with springs that have static deflections in the 5 to 5 mm range to meet the design criteria described in type. Flexible elastomeric seals are typically most effective for weatherproofing between the upper and lower frames. continuous sponge gasket around the perimeter of the top frame is typically applied to further weatherproof the installation. Notes for Selection Guide for Vibration Isolation Note : deflections shown are based on reasonably expected floor stiffness according to floor span and class of equipment. ertain spaces may dictate higher levels of isolation. For example, bar joist roofs may require a static deflection of 8 mm over factories, but 6 mm over commercial office buildings. Note : For large equipment capable of generating substantial vibratory forces and structure borne noise, increase isolator deflection, if necessary, so isolator stiffness is less than onetenth the stiffness of the supporting structure, as defined by the deflection due to load at the equipment support. Note : For noisy equipment adjoining or near noisesensitive areas, see the section on Mechanical Room Sound isolation. Note : ontain designs cannot be installed directly on individual isolators (type ), and the equipment manufacturer or a vibration specialist should be consulted on the need for supplemental support (base type). Note 5: Wind load conditions must be considered. Restraint can be achieved with restrained spring isolators (type ), supplemental bracing, snubbers, or limit stops. Note 6: ertain types of equipment require a curbmounted base (type D). irborne noise must be considered. Note : See section on Resilient Pipe Hangers and Supports for hanger locations adjoining equipment and in equipment rooms. Note 8: To avoid isolator resonance problems, select isolator deflection so that resonance frequency is 0% or less of the lowest normal operating speed of equipment (see hapter 8 in the 009 SHRE Handbook Fundamentals). Some equipment, such as variablefrequency drives, and highspeed equipment, such as screw chillers and vaneaxial fans, contain veryhighfrequency vibration. This equipment creates new technical challenges in the isolation of highfrequency noise and vibration from a building s structure. Structural resonances both internal and external to the isolators can significantly degrade their performance al high frequencies. Unfortunately, at present no test standard exists for measuring the highfrequency dynamic properties of isolators, and commercially available products are not tested to determine their effectiveness for high frequencies. To reduce the chance of highfrequency vibration transmission, add a 5 mm thick pad (type, Note 0) to the base plate of spring isolators (type, Note,, ). For some sensitive locations, air springs (Note 5) may be required. If equipment is located near extremely noisesensitive areas, follow the recommendations of an acoustical consultant. Note 9: To limit undesirable movement, thrust restraints (type 5) are required for all ceilingsuspended and floormounted units operating at 500 Pa or more total static pressure. Note 0: Pumps over 55 kw may need extra mass and restraints.

5 Selection Guide for Vibration Isolation ategory Horsepower and Other RPM ase Slab on Grade Up to 0 ft (6 m) Floor Span ase Location 0 to 0 ft (6 9 m) Floor Span 0 to 0 ft (9 m) Floor Span ase ase Reference Notes pg 6 KINETIS Products Meeting Selection riteria ase No base, isolators attached directly to equipment Refrigation Machines and hillers ir ompressors and Vacuum Pumps Pumps Reciprocating entrifugal, scroll Screw bsorption ircooled recip., scroll ircooled screw Tankmounted horiz. Tankmounted vert. asemounted Large Reciprocating lose oupled Inline End Suction and Double suction/split ase Packaged Pump Systems ll ll ll ll ll ll 0 5 ll ll ll to to 5 50 ll ll ll ll ll ll ll ll ll ll ll ll ll ll ll ll ll ll ll ll.00 (5).00 (5).50 (8).50 (8).50 (8).50 (8).50 (8).50 (8).50 (8).50 (8).50 (8).50 (6).50 (8).50 (8).50 (6).50 (8).50 (8).50 (8).50 (8).50 (8).50 (8).50 (8).50 (8).50 (8).50 (8).50 (6).50 (8).50 (6).50 (8).50 (6).50 (8).50 (6).50 (6).50 (8).50 (8).50 (8).50 (8).50 (8).50 (8).50 (8).50 (6).50 (8).50 (6).50 (89).50 (6),,,,,8,,,,,,5,,,5,8,,5,5,5,,5,, ,6 0,6 ase ase ase D Structural Rail ase, Model S Integral Structural eam ase, Model SF oncrete Inertia ase, Model IL Model IH Model ISS Roof urb Rail, Model KSR Model KSR Roof urb Rail, Model ESR Fiberglass Isolation Pad, Model KIP ooling Towers oilers xial Fans, Plenum Fans, abinet Fans, Fan Sections, entrifugal Inline Fans entrifugal Fans Propeller Fans Heat Pumps, Fan oils, omputer Room Units ondensing Units H,, H, and V Units Packaged Rooftop Ducted Rotating ll Firetube Watertube, cooper fin Up to in. diameter in. diameter and up Up to in. diameter in. diameter and up WallMounted Roof Exhauster ll ll ll ll ll Small fans, fanpowered boxes ll ll ll ll in. SP. in. SP ll 0 50 ll ll ll ll 0 5, in. SP >5, > in. SP ll 600 cfm 600 cfm Up to 00 0 to 500 ll ll ll Up to 00 0 to 500 Up to 00 0 to 500 ll Up to 00 0 to 500 Up to 00 0 to 500 ll ll ll ll ll Up to 00 0 to 500 Up to 00 0 to 500 ll /D 0. ().50 (6).50 (6).50 (8).50 (6).50 (8).50 (6).50 (8).00 (5) 0.50 () D.50 (89).50 (6) 0. ().50 (89).50 (8).50 (8).50 (89).50 (8).50 (8).50 (89).50 (8).50 (89).50 (8).50 (8).50 (89).50 (6).50 (8).50 (89).50 (8).50 (8) 0.50 ().50 (89).50 (6).50 (8) 0. ().50 (89).50 (6).50 (8).50 (89).50 (6).50 (8).50 (89).50 (6).50 (89).50 (6).50 (8).50 (8).50 (8).50 (89).50 (6).50 (8).50 (89).50 (6).50 (8) 0.50 () D /D /D.50 (89).50 (6).50 (8).50 (6).50 (89).50 (6).50 (8).50 (89).50 (6).50 (6).50 (8).50 (89).50 (6).50 (8).50 (89).50 (6).50 (6).50 (8).50 (8).50 (8).50 (89).50 (6).50 (8).50 (89).50 (6).50 (6) 0.50 () 5,8,8 5,8 5,8,8,9 8,9 8,9 8,9,8,9,8,9,8,9 9,9 8,9 8,9 8,9,,8,9,9,,8,9,9,,8,9,9 9,,8,9,9,9,,,8,9,,,9,,,9 5,6,8, 5 6 Neoprene Isolation Pad, Model NP Model NG Model RSP Fiberglass Isolation Mount, Model Neoprene Isolation Mounts, Model RD Model RQ Isolation Hanger, Model FH Model RH Freestanding Steel Spring, Model FDS House Spring s, Model SL Model SM Isolation Hangers, Model SFH Model SRH Model SH Restrainted Spring, Model TITN Model FMS Model FLS Model FLSS Model FHS Model FRS Thrust Restraint, Model HSR ir Spring, Model KM Model M EngineDriven Generators ll ll ll.50 (8).50 (6).50 (89),, Source: 0 SHRE Handbook

6 Isolation for Specific Note Refrigeration Machines: Large centrifugal, screw, and reciprocating refrigeration machines may generate very high noise levels; special attention is required when such equipment is installed in upperstory locations or near noisesensitive areas. If equipment is located near extremely noisesensitive areas, follow the recommendations of an acoustical consultant. Note ompressors: The two basic reciprocating compressors are duct structures. () single and doublecylinder vertical, horizontal or Lhead, which are usually air compressors; and () Y, W, and multihead or multicylinder air and refrigeration compressors. Single and doublecylinder compressors generate high vibratory forces requiring large inertia bases (type ) and are general y not suitable for upperstory locations. If this equipment must be installed in an upperstory location or atgrade location near noisesensitive areas, the expected maximum unbalanced force data must be obtained from the equipment manufacturer and a vibration specialist consulted for design of the isolation system. Note ompressors: When using Y, W, and multihead and multicylinder compressors, obtain the magnitude of unbalanced forces from the equipment manufacturer so the need for an inertia base can be evaluated. Note 5 ompressors: asemounted compressors through kw and horizontal tanktype air compressors through 8 kw can be installed directly on spring isolators (type ) with structural bases (type ) if required, and compressors 005 kw on spring isolators (type ) with inertia bases (type ) with a mass I to limes the compressor mass. Note 6 Pumps: oncrete inertia bases (type ) are preferred for all flexiblecoupled pumps and are desirable for most closecoupled pumps, although steel bases (type ) can be used. losecoupled pumps should not be installed directly on individual isolators (type ) because the impeller usually overhangs the motor support base, causing the rear mounting to be in tension. The primary requirements for type bases are strength and shape to accommodate base elbow supports. Mass is not usually a factor, except for pumps over 55 kw, where extra mass helps limit excess movement due to starting torque and forces. oncrete bases (type ) should be designed for a thickness of onetenth the longest dimension with minimum thickness as follows: () for up to 0 kw, 50 mm; () for 0 to 55 kw, 00 mm; and () for 5 kw and up, 00 mm. Pumps over 55 kw and multistage pumps may exhibit excessive motion at startup ( heaving ); supplemental restraining devices can be installed if necessary. Pumps over 90 kw may generate high starting forces; a vibration specialist should be consulted. Note Packaged Rooftop ironditioning : This equipment is usually installed on lowmass structures that are susceptible to sound and vibration transmission problems. The noise problems are compounded further by curbmounted equipment, which requires large roof openings for supply and return air. The table shows type D vibration isolator selections for all spans up top 6 m, but extreme care must be taken for equipment located on spans of over 6 m, especially if construction is open web joists or thin, lowmass slabs. The recommended procedure is to determine the additional deflection caused by equipment in the roof. If additional roof deflection is 6 mm or less, the isolator should be selected for 0 times the additional roof deflection. If additional roof deflection is over 6 mm, supplemental roof stiffening should be installed to bring the roof deflection down below 6 mm, or the unit should be relocated to a stiffer roof position. For mechanical units capable of generating high noise levels, mount the unit on a platform above the roof deck to provide an air gap (buffer zone) and locate the unit away from the associated roof penetration to allow acoustical treatment of ducts before they enter the building. Some rooftop equipment has compressors, fans, and other equipment isolated internally. This isolation is not always reliable because of internal shortcircuiting, inadequate static deflection, or panel resonances. It is recommended that rooftop equipment over 5 kg be isolated externally, as if internal isolation was not used. Note 8 ooling Towers: These are normally isolated with restrained spring isolators (type ) directly under the tower or lower dunnage. High deflection isolators proposed for use directly under the motorfan assembly must be used with extreme caution 0 ensure stability and safety under all weather conditions. See Note 5. Note 9 Fans and irhandling : onsider the following in selecting isolation systems for fans and airhandling equipment:. Fans with wheel diameters of 560 mm and less and all fans operating at speeds up to 00 rpm do not generate large vibratory forces. For fans operating under 00 rpm, select isolator deflection so the isolator natural frequency is 0% or less than the fan speed. For example, for a fan operating at 5 rpm, 0. x 5 = 0 rpm. Therefore, an isolator natural frequency of 0 rpm or lower is required. This can be accomplished with a 5 mm deflection isolator (type ).. Flexible duct connectors should be installed at the intake and discharge of all fans and airhandling equipment to reduce vibration transmission 0 air. Inertia bases (type ) are recommended for all class and fans and airhandling equipment because extra mass allows the use of stiffer springs, which limit heaving movements.. Thrust restraints (type 5) that incorporate the same deflection as isolators should be used for all fan heads, all suspended fans, and all basemounted and suspended airhandling equipment operating at 500 Pa or more total static pressure. Restraint movement adjustment must be made under normal operational static pressures.

7 Engineering apabilities elebrating our 50th year in 008, Kinetics Noise ontrol has extensive experience in the design, manufacturing and application of innovative products to control sound and vibration. Kinetics pioneered development of precompressed, molded fiberglass pad isolators that would be incorporated into a dynamic new floor isolation system. Kinetics Noise ontrol now produces the industry s largest selection of inspired products to address vibration and noise control, room acoustics, and seismic restraint concerns for almost any application. Value is added with our experienced team of engineering and customer support personnel ready to work with you. Kinetics Noise ontrol features extensive practical experience in both design and application. The experienced staff of over twenty (0) technically trained individuals includes seven () licensed professional engineers, two () holding Master s degrees and one () who has earned a Ph.D., spread across engineering and manufacturing centers in Ohio, US, Ontario, anada, and Hong Kong, hina. Our combined technical experience exceeds 00 years with over 50 years directly related to sound, vibration control and seismic issues. Kinetics Noise ontrol employees hold PE licenses in 0 states and provinces. Select Projects ir anada, Winnipeg James rmstrong Richard International irport Manitoba, liante Station Las Vegas ltus ir Force ase, ltus F, OK RI Hotel and asino at ityenter, Las Vegas rmy viation Support Facility, Santa Fe, NM arrie Fire Station, arrie, Ontario aledon OPP Station, aledon (Toronto), Ontario asino Niagara ity of North Las Vegas Water Reclamation Facility, Las Vegas, NV osmopolitan of Las Vegas Ford Plant (Water Treatment Facility), Oakville, Ontario Ft arson Firing Range, Ft arson, O Ft. Detrick hevron, Ft. Detrick, MD Ft. Lewis T omplex, Ft. Lewis, W Grand Hyatt Macau at ity of Dreams Grand Junction Public Safety uilding, Grand Junction, O Hard Rock Hotel Macau at ity of Dreams Harmon Tower at ityenter, Las Vegas Hollywood asino, Lawrenceburg, Indiana Indian Springs orrectional Facility, Indian Springs, NV Ireland rmy ommunity Hospital, Fort Knox, KY Langley ir Force ase, Hampton, V The M Resort Spa asino Las Vegas Mandarin Oriental Las Vegas at ityenter Moody ir Force ase ommissary, Moody F, G Mt. Sinai Hospital, Toronto, Ontario New Jersey ir National Guard Operation and Training P6 MH60S Hangar and irfield Improvements, Norfolk, V Pearlgate Recreational Multiplex, ity of Mount Pearl, Newfoundland, (NS), Peel Regional Police Station, Peel (Toronto), Ontario Seal Operations Facility P, Norfolk, V Syracuse V Medical enter, Syracuse, NY St. Joseph s Hospital, Hamilton, Ontario Toronto Police Station, Toronto, Ontario United States ourthouse, Jefferson ity, MO USO Tier III, Golden, O V Hospital Mental Health Outpatient, Salisbury, N Vdara Hotel and Spa at ityenter, Las Vegas Venetian Hotel Phantom Theatre in Las Vegas Wm. Jennings ryan Dorn V Medical enter, olumbia, S Women s ollege Hospital, Toronto, Ontario Woodstock General Hospital, Woodstock, Ontario York Regional Police Headquarters, York, Ontario kineticsnoise.com/seismic/titan.html [email protected] Manufacturing facilities in Ohio, US; alifornia, US; and Ontario, anada. Sales offices worldwide. Kinetics Noise ontrol, Inc. is continually upgrading the quality of our products. We reserve the right to make changes to this and all products without notice. HV SELETION GUIDE /