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complicate the vibration problem. Steel encased concretebases provide a simpler rigid design. While adding mass willreduce vibratory motion in direct proportion to the increase intotal weight, all modern HVAC equipment can be mounted

directly on steel bases without excessive motion. Therefore,concrete bases should be designed for stiffness as there is noneed for additional mass.

4. Isolated equipment should be made as free to move aspossible and not restricted by connected piping or ductwork.While this can be done with rigid piping having multiple bendsand spring hanger suspension, we believe that flexible rubberconnectors still remain the most fool proof method. To do this,Kevlar reinforced double arch expansion joints are usuallyinstalled without control rods, either horizontally or vertically. Ifcontrol rods must be used at very high pressures, the bestmode is horizontal and parallel to the equipment shaft as theywill only function radially. Flexible rubber connectors reducenoise and vibration at hydraulic pumping frequency (RPM xnumber of pump blades) but are ineffective at RPM.

5. Improper isolation of piping can bypass equipment supportmountings. Therefore, mechanical piping should be treated aspart of the machine and as much thought given to the pipingisolation as to the machinery itself. Since piping is subject toexpansion and dynamic forces, sometimes there is need forcompromise and we must provide resilient anchors to directpiping motion, and avoid pipe stress which might lead to pipefailure or damage to the structure. We do not believe that it isalways practical to completely float a riser without providingresilient anchors when there are many branch-offs that tend tobind or offer unpredictable resistance.

In writing the VCS-100 specifications we have always tried toabide by the theory contained in our lecture to the ASHRAEAssociation and to temper this theory with studies of oursuccessful installations and of even greater importance, recordkeeping of what had to be done to correct problem jobs,

installed by our firm or others. The ASHRAE Lecture bulletin isimmediately before this publication.

In earthquake zones the information provided by VCS-100 mustbe supplemented with some form of snubbing and preferablywith snubbers that are selected with an eye to maximummovements and accelerations as the result of a computer studyof the isolated machine and the earthquake that would affect it.Supplementary snubbing information can be found in our bulletinSCS-100 and Specification Bulletins SVCS.

Although engineers are generally more concerned with vibrationtransmission than airborne noise, there are those applicationswhere airborne sound transmission is as important as vibrationisolation. Information as to the proper design of floating floors,suspended ceilings and improved wall construction can befound in our architectural bulletin ACS-102.

Since our first publication of VCS-100 in 1965, we havedistributed over 350,000 copies throughout the world. Thesepresentations formalized specification writing in our industryand the greatest compliment is not only usage, but the fact thatmuch of the information has been copied by our competitors.This new publication presents the specifications in finished formin both disk and hard copy. It can be used as written or editedto conform with your experience.

Very truly yours,

MASON INDUSTRIES, INC.

N.J. Mason, President

To The Specifying Engineer:

In 1962 we introduced our first HVAC ENGINEERINGSPECIFICATION. While the 1962 approach was very wellreceived and filled a void, it was made up of many individualspecifications rather than presented in an organized format. Ithad no meaningful minimum static deflection guide andengineers found it hard to work with.

In 1965 we started the VCS series which was the first industryattempt to hone in on a specific group of HVAC products ratherthan the complete isolator range. It made it possible for theengineer to work with a small, versatile group of products andget to know them well. The 1965 specification included the firstselection chart as an additional engineering tool highlighting theneed for increased deflection in response to floor sensitivity andgreater vibratory input from larger machines. These empiricalsuggestions written 35 years ago were based on 20 years ofhands-on experience correcting bad installations on aguaranteed solution basis.

The 1965 series remained virtually unchanged until 1975, when

we started publishing in the present format. The 1976, 1979 and1982 modifications, all represented better explanations, productimprovement or changes in the selection guide.

In this issue we have added air springs, sliding pipe guides,complete roof top spring curbs, DuPont Kevlar reinforcedexpansion joints, completely engineered riser systems andchanges in piping supports. Hopefully, our introduction of newor improved methods will never stop. This new specificationcontinues to incorporate the principles that have always beenour guidelines.

1. The s ing le deg ree o f f r eedommathematical Efficiency chart andequation is only a theoreticalrepresentation as it erroneously assumesgreat stiffness or mass under the

isolators. This is not true in modernbuildings. Older specifications called for atheoretical Isolation Efficiency that wasusually inadequate for high speed and tooconservative for low speed equipment.Static deflection requirements should bestated specifically and increased in keeping with floordeflections. For any given operating speed there will be a needfor a larger spring deflection as the equipment is located inareas with longer unsupported spans because the floorsbecome more flexible and vibration prone. Vibratory energytends to increase with horsepower, so as a family of equipmentsuch as pumps, become larger, there is need for moredeflection. Once past a ratio of 3 between the operating speedand the natural frequency (bouncing frequency) of the springsystem, vibration transmission is reduced in direct proportion tothe increase in spring deflection.

2. A spring isolator should be designed to utilize largediameter springs with a horizontal stiffness that is a minimum of75% of the vertical. For all practical purposes, this can beverified if the outside spring diameter is not less than 0.8 of thecompressed height of the spring at rated load. These springsrequire no housing for lateral stability. While housings may berequired for other reasons, such as wind load or restraint whenweight changes because of water drainage, housings must bedesigned so they do not influence the spring frequency in anydirection during normal operation.

3. S tee l bases should be made r ig id to main ta in thealignment of the equipment and resist both belt tension andtorsional forces. It is also important that base members are stiffso they resonate at much higher frequencies than thosegenerated by the isolated equipment. Base members that

resonate at disturbing vibratory frequencies can seriously

VCSVCS-100-8.2 BULLETIN

COMPLETE HVAC

ENGINEERING

SPECIFICATIONS

First Printing 1965 Revised 1973, 1974, 1975, 1976, 1979, 1982, 4/2001, 9/2001 & NOVEMBER 2003

MASON INDUSTRIES, Inc.Manufacturers of Vibration Control Products

350 Rabro Drive 2101 W. Crescent Ave., Suite DHauppauge, NY 11788 Anaheim, CA 92801

631/348-0282 714/535-2727FAX 631/348-0279 FAX 714/535-5738

[email protected] [email protected]: www.Mason-Ind.com

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VCS-100 remains unique, because there are engineering design explanations on the lefthand side of eachpage to provide the reasons why we suggest the specification on the right. In personal meetings withthousands of engineers, this presentation has been invaluable in developing a broad understanding ofquality design and application standards and why our isolators are built as they are.

None of our products are patented. There is no reason to accept an inferior cheapened substitute should acompetitor have no pride in their product. We certainly hope that you find this tool useful and we continue toinvite your comments as to its improvement.

PRODUCT PAGES CONTENTS

FLOOR MOUNTINGS 3 - 5

HANGERS & HORIZONTAL 5 - 7THRUST RESTRAINTS

BASES 8 - 9

ROOF CURBS 10 - 11

FLEXIBLE CONNECTORS & SEALS 12 - 13

PIPE ANCHORS 13

RISER GUIDES &14HORIZONTAL PIPE ISOLATION

PIPE RISER ISOLATION 15

DUCT ISOLATION 16

SPECIFICATION WRITING 16

SAMPLE ISOLATION SCHEDULE 17

SPECIFICATION SELECTION GUIDE 18 - 19

BLOWER MINIMUM DEFL. GUIDE 19

GUIDE NOTES 20

COMPLETE SPECIFICATION 21 - 27

SPECIFICATION ILLUSTRATIONS 28 - 32

EXPLANATIONS AND DESIGN CONSIDERATIONS SPECIFICATIONS

INDEX

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EXPLANATION & DESIGN CONSIDERATIONS SPECIFICATIONS

MOUNTINGS

Double deflection neoprene mountings and double deflectionrails are recommended for minor equipment or basementlocations only. We have placed this limitation on all rubberlikematerials because of their relatively minor deflections.

MOUNTINGS

SLF spring mountings are our standard for all high efficiency

installations. This is a bare spring design with a good ratiobetween the diameter and the working height to assure lateralstability. Our suggested specification states that the springdiameter shall be no less than 0.8 of the compressed height ofthe spring at rated load. This is easily checked in the submittaland review process. This minimum ratio will result in a horizontalstiffness no less than 0.75 of the vertical, in virtually all cases.Should you be interested in the specifics of the design, pleaserefer to bulletin SLF-200.

Some of our competitors are still publishing a minimum diameterchart rather than a ratio. This method of specification isquestionable. If literally enforced, the call for a proprietarymanufacturer's diameter would eliminate all competition. Inreality, it is only the proportion of the spring that is important andthis can only be expressed as a ratio rather than a specific size.For example, if a spring were specified 5 inches in diameter and5 inches high with a spring constant of 1,000 pounds per inch, itwould have about the same lateral stability as a spring 4 inchesin diameter and 4 inches high designed with better quality springsteel capable of handling higher stresses as offered by anothervendor.

The minimum 50% additional travelcompensates for errors that creep inbecause of faulty weight data. This alsomeans the springs will operate at lowerstress which further guarantees theirpermanency. The neoprene friction pad onthe bottom acts as a sound break for somehigh frequencies which may travel down thespring wire. The pad also eliminates theneed for bolting in virtually all applications.Bolting is preferable on steel or overheadlocations.

SPECIFICATION A

Neoprene mountings shall have a minimumstatic deflection of 0.35(9mm). All metalsurfaces shall be neoprene covered andhave friction pads both top and bottom. Boltholes shall be provided on the bottom and atapped hole and cap screw on top. Steel

rails shall be used above the mountingsunder equipment such as small vent

sets to compensate for theoverhang. Mountings shall betype ND or rails type DNR asmanufactured by MasonIndustries, Inc.

SPECIFICATION B

Spring isolators shall be free standing andlaterally stable without any housing andcomplete with a molded neoprene cup or1/ 4(6mm) neoprene acoustical friction padbetween the baseplate and the support. Allmountings shall have leveling bolts thatmust be rigidly bolted to the equipment.Installed and operating heights shall beequal. The ratio of the spring diameterdivided by the compressed spring heightshall be no less than 0.8. Springs shall havea minimum additional travel to solid equal to50% of the rated deflection. Submittals shallinclude spring diameters, deflection,compressed spring height and solid springheight. Mountings shall be type SLF, asmanufactured by Mason Industries, Inc.

SLF Spring Mount

ND Neoprene Mount

CAP SCREW SECURESEQUIPMENT TO MOUNTING

STEEL PLATESTOP ANDBOTTOM ARENEOPRENECOVERED TOPREVENTCORROSIONAND PROVIDEFRICTION DNR Rails

CAP SCREW SECURESEQUIPMENT TO

ADJUSTMENT BOLT

HEIGHT SAVINGBRACKET

DUCTILE HOLDERSTOP AND BOTTOM

1/4(6mm) NON-SKIDACOUSTICALISOLATION PAD

ADJUSTMENTBOLT

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MOUNTINGS

It is possible to reach frequencies as low as 84 cpm(1.4 hz) or evenlower using steel springs and provide excellent isolation at RPM or thefundamental frequency, but noise transmission is another issue. Thehigh pitched whines and hums developed by very high speedcentrifugal, screw and sometimes reciprocating compressors, as wellas transformers, travels axially through the spring wire and comesthrough the bottom spring coil with little reduction. While a rubber padwill reduce this noise, it has been our experience on many occasions

that no matter how many layers of rubber pads were used (we havebuilt up to 6[150mm]), the noise will still find its way through. We neveruse pads harder than 60 durometer, but harder pads (65 duro andhigher) are even more sound transparent.

Air springs completely eliminate this problem. Support is provided bypressurized air within a thin walled rubber container similar to but lighterthan the side walls of an automobile tire. We have never experiencedhigh frequency noise transmission when using air springs, as the soundis not transmitted by the air or the tire cord reinforced neoprene body.

There is always some air leakage no matter how slow. After systemsare installed, they are seldom inspected and maintained. Ourexperience has proven it is mandatory that the air springs are installedwith an air supply and height sensitive (not pressure sensitive) controlvalves. The valves provide additional air if elevation is lost or vent if theelevation increases due to rotational forces or temperature increase.Temperature increases occur on hot roofs or within transformer vaults.Air usage is minimal. Most of the time the system is supplied by controlair. If not available, the smallest available tank type compressor is morethan adequate if it will operate at the air spring rated pressure. Thiscompressor is often mounted on the primary equipment so it is selfisolated.

We strongly recommend air springs in critical areas where noisetransmission is a major worry.

MOUNTINGS

SLR and SLRS restrained mountings limit upward travel when weight istemporarily removed and provide safety stops for windy rooftopapplications. All mountings are shipped with removable steel spacers

between the sides and the top plate of the mounting as shown in theillustration. When the spacer is in place, the mountings are rigid blocksthat support the equipment at elevation before spring adjustment. Afterthe springs are adjusted to take the load, the spacers are removed toprovide the operating clearance without changing the height of themounting. The stop nut is adjusted to provide a clearance of0.125(3mm) to complete the adjustment. When there is a radical weightchange, such as the water and refrigerant being removed from a chiller,the water drained from a steam generator or a cooling tower, the upwardspring expansion is limited by the clearance under the stop nut.

In extremely windy situations, overturning is limited to this samemovement plus the downward movement of the mountings on theopposite side. In most countries, other than those experiencing stormswith higher velocities, designs are based on100 mile winds which exert apressure of 30 lbs. per square foot on the equipment. The force can becalculated using the largest vertical surface to check whether the housingrating of the mountings is adequate, both horizontally and vertically.

The call out of minimum clearancearound the restraining bolts is veryimportant, since it offers someassurance that the springs willnot be short circuited when thereis minor misalignment of thehousings because of structuraltolerances in the steel work orattachments. SLR's and SLRSsare used under chillers and steamgenerators as well as roof topequipment such as cooling towers,heating and ventilating units andblowers. They are often used aspipe horizontal supports as well,because the upper steel surface

facilitates stanchion attachment.

SPECIFICATION C

Multiple bellow air springs shall be manufacturedwith powder coated upper and lower steel sectionsconnected by a replaceable, flexible Nylon reinforcedNeoprene element to achieve a maximum naturalfrequency of 3 Hz. (We have found 3 Hz adequatewhen using air springs. Should the specifyingengineer require a lower frequency, change the 3 Hzto the lower number). Burst pressure must be aminimum of 3 times the published maximumoperating pressure. All air spring systems shall beequipped with 3 leveling valves connected to thebuilding control air or a supplementary air supply tomaintain elevation plus or minus 1/ 8(3mm). An airfilter and water separator shall be installed beforethe air distribution system to the leveling valves.

Submittals shall include natural frequency, as well asload and damping tests, all as performed by anindependent lab or acoustician. Air springs shall bytype MT and leveling valves type LV asmanufactured by Mason Industries, Inc.

SPECIFICATION D

Equipment with large variations in the operatingand installed weight, such as chillers, boilers, etc.,and equipment exposed to the wind such as coolingtowers, roof mounted fans and roof mounted airhandling equipment shall be mounted on springmountings, as described in EngineeringSpecification B, including the neoprene acousticalpad within a rigid sided housing that includesvertical limit stops to prevent spring extension whenweight is removed and temporary steel spacersbetween the upper and lower housings. Housingsshall serve as blocking during erection. When theequipment is at full operating weight, the springsshall be adjusted to assume the weight and thespacers removed, without changing the installedand operating heights. All restraining bolts shallhave large rubber grommets to provide cushioning

in the vertical as well as horizontal modes. The holethrough the bushing shall be a minimum of 0.75(20mm) larger in diameter than the restraining bolt.Horizontal clearance on the sides between thespring assembly and the housing shall be aminimum of 0.5(12mm) to avoid bumping andinterfering with the spring action. Vertical limit stopsshall be out of contact during normal operation.Cooling tower mounts are to be located betweenthe supporting steel and the roof or the grillage anddunnage as shown on the drawings when there isno provision for direct mounting. Housings andsprings shall be powder coated and hardwareelectro-galvanized. Mountings shall be SLR orSLRS as manufactured by Mason Industries, Inc.

LV Leveling Valve

TAPPED HOLEFOR ATTACHMENT

AIR SUPPLYCONNECTION

NEOPRENE FRICTION PAD

DOUBLE BELLOWSNYLON REINFORCEDNEOPRENE ELEMENT

Air Springs must be installedwith Leveling ValvesMT Air

Spring

VERTICALLIMIT STOPS

ADJUSTMENTBOLTREMOVABLESPACER

RIGIDHOUSING

INTERNALNEOPRENEACOUSTICALPAD

EXTERNAL NEOPRENE FRICTION

PAD (Remove if welding in place.)

NEOPRENEDOWN STOP

NEOPRENEBUSHING

SLRMount

SLRS

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SPECIFICATION E

Equipment with large variations in the operating aninstalled weight, such as chillers, boilers, etc., andequipment exposed to the wind such as coolingtowers, roof mounted fans and roof mounted aihandling equipment shall be mounted on air springsas described in Engineering Specification C, but withia rigid sided housing that includes vertical limit stopto prevent spring extension when weight is removedand temporary steel spacers between the upper andlower housings. Housings shall serve as blockingduring erection. When the equipment is at fuoperating weight, the air springs shall be pressurizedto take the weight so the spacers can be removedwithout changing the installed and operating heightsAll restraining bolts shall have large rubber grommetto provide cushioning in the vertical as well as thhorizontal modes. The hole through the bushing shalbe a minimum of 0.75(20mm) larger in diameter thathe restraining bolt. Horizontal clearance between theair spring assembly and the housing shall be aminimum of 0.5(12mm) to avoid bumping aninterference with the air spring action. Vertical limstops shall be out of contact during normal operationMountings and air spring parts shall be powdecoated. Hardware electro-galvanized. Air sprinsystems shall be connected to the building control airor a supplementary air supply and equipped with threeleveling valves to maintain level within plus or minu0.125(3mm). Cooling tower mounts are to be locatebetween the supporting steel and the roof or thegrillage and dunnage as shown on the drawings whenthere is no provision for direct mounting. Mountingshall be SLR-MT and leveling valves type LV amanufactured by Mason Industries, Inc.


MOUNTINGS

SLR-MT restrained mountings contain MT air springs in place ofthe SLF springs in the SLR mountings. The steel housing aroundthe MT air spring serves exactly the same purpose as the SLRhousing in explanation D. SLR-MT are recommended in lieu ofSLR in highly critical situations as described for the MT.

SPECIFICATION F

Hangers shall consist of rigid steel framescontaining minimum 1 1 / 4 (32mm) thicneoprene elements at the top and a steelspring with general characteristics as inspecification B seated in a steel washerreinforced neoprene cup on the bottom. Theneoprene element and the cup shall have

neoprene bushings projectingthrough the steel box. In order tomaintain stability the boxes shallnot be articulated as clevishangers nor the neoprene elementstacked on top of the spring.Spring diameters and hanger boxlower hole sizes shall be largeenough to permit the hanger rod toswing through a 30 arc from sideto side before contacting the cupbushing and short circuiting thespring. Submittals shall include ahanger drawing showing the 30capability. Hangers shall be type30N as manufactured by MasonIndustries, Inc.

HANGERS

We have worked with combination spring and neoprene hangersfor over 40 years. This serial arrangement of materials isextremely effective. Our older designs, and all of the standarddesigns of our competitors had the common fault of not allowingenough angular hanger rod misalignment. The rod could strikethe side of the hanger box where the rod passes through thehole and short circuit the spring. In order to solve the problem, itwas necessary to design a new series of springs that wererelatively short and larger in diameter sowe could enlarge the size of the hole inthe bottom of the hanger box. Another

improvement was the molding of aneoprene cup that sockets the spring andprovides a protective bushing where therod passes through the hanger box hole.The thirty degree requirement is a way ofdescribing this clearance and the calloutof a scale drawing of thehanger to show thiscapability is the onlyassurance that no one willsubmit a look alike thatdoes not have thisimportant capability.

30N HangerObsolete 1965

DNHS Hanger

c c c

c c c c

c c c c

c c c

VERTICAL

LIMIT STOPS

NEOPRENEDOWN STOP

NEOPRENEBUSHING

REMOVABLESPACER

RIGIDHOUSING

DOUBLEBELLOWSNYLONREINFORCEDNEOPRENEELEMENT

INTERNALNEOPRENEFRICTION PAD

EXTERNAL NEOPRENEFRICTION PAD (Remove

if welding in place)

AIR SPRINGS MUSTBE INSTALLED WITHLEVELING VALVES

SLR-MT Air Spring Mount

LV Leveling Valve

RIGID STEEL FRAME

MINIMUM 11/ 4(32mm)

THICK NEOPRENEELEMENT WITHPROJECTING RODISOLATION BUSHING

NEOPRENE SPRINGCUP WITHPROJECTING RODISOLATION BUSHING

ROD CAN SWING30 BEFORECONTACTINGRESILIENT BUSHING

30

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HANGERS

While hanger adjustment along the run of a pipe may not be toocritical, it is important that the pipe weight is kept off isolatedequipment in order to maintain alignment, protect cast flangesand flexible hoses. Should the piping weight fall on theequipment, the floor mountings become overloaded andinoperative. Eighteen years ago, we called for a type PDNHS

hanger. This design did not have clearances as described inSpecification D for the new 30N and our method of maintainingthe elevation was to build the hanger with a firm platform abovethe spring and then to ask the contractor to follow the procedureof loading the spring and ultimately relieving this upper nut. Thiswas very difficult to do, and in many cases it was not done at all,so the hangers remained solid hangers. While a theoreticalspecification may be convincing, we are all interested inperformance so there was no point in continuing to call for adevice that could not be adjusted properly.

Therefore, we changed the specification to call for the typePC30N as illustrated. Rather than a rigid secondary platform, we

preload this hanger in our factory so that it is shipped with therated deflection shown on the indicator. It remains a constantelevation device because the springs do not deflect additionallywhen the contractor adds the load. In order to make the hangeroperative, he does not have to wind up the spring, but merelyto release the spring by unlocking the nut at the bottom. If ourassumed weight is incorrect, there will be a very minor upwardmovement as the spring assumes the exact load. While thesehangers do not do the job as precisely as the old design, theyare much less expensive to install and for all practical purposesthe systems will be much better for our having made this changein our recommendations, as all hangers will be functional.

There is a strong need for these hangers near the equipmentand that is the reason that we call for the first four hangers to beType PC30N. They are also recommended for other situations,where you want a precise installation. They are particularlyuseful when hanging pipe that is 6 inches in diameter and larger,as they keep the pipe run level as the installation proceeds.When a contractor uses a standard hanger that deflects as pipeis added, it is very difficult to put large pipe in properly. In manycases, the contractor will install solid rods to begin with and thencut the rods and install the spring hangers later. This is a veryexpensive procedure that can be eliminated by using pre-compressed hangers throughout. It is a matter of economics.

In our specification, we call for this design for the first fourhangers from the equipment (30 feet 10 meters ). You can modifythat requirement plus or minus should you edit our specification.

SPECIFICATION G

Hangers shall be as described in F, but theyshall be precompressed and locked at therated deflection by means of a resilientupstop to keep the piping or equipment at afixed elevation during installation. Thehangers shall be designed with a releasemechanism to free the spring after theinstallation is complete and the hanger issubjected to its full load. Deflection shall beclearly indicated by means of a scale.Submittals shall include a drawing of thehanger showing the 30 capability. Hangersshall be type PC30N as manufactured byMason Industries, Inc.

PC30N Hanger

Obsolete 1965PDNHS Hanger

RIGID STEEL FRAME

MINIMUM 11/ 4(32mm)THICK NEOPRENEELEMENT WITHPROJECTING RODISOLATION BUSHING

NEOPRENE SPRING CUPWITH PROJECTING RODISOLATION BUSHING

PRECOMPRESSION PLATEWITH NEOPRENE WASHER

ROD CAN SWING 30BEFORE CONTACTINGRESILIENT BUSHING

30

DEFLECTION SCALE

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HANGERS

The W30 hanger is satisfactory for duct isolation since ductsvibrate at lower frequencies than piping and there is no highfrequency component requiring a full Neoprene element. Thissimple spring hanger retains the 30 capability, but the housingis manufactured so that it may be attached to flat straps ratherthan rods. If rods are used rather than flat straps, the Type 30serves the same purpose.

HORIZONTAL THRUST RESTRAINTS

It is not unusual to encounter problems where the horizontalcombined air thrust exceeds 10% of the equipment weight. If thespring columns alone resist a 10% force, they will lean over

about 12% of the rated deflection. This is the recommendedmaximum.

When the thrust is higher, the best solution is adding mass tobring the ratio back down to 10%. If adding mass is impractical,horizontal restraints are another possibility. This is particularlytrue of fan heads, but high pressure axial and centrifugal fansmay present the same problem. The equipment may be hung orfloor mounted. Our horizontal restraint is a modified springhanger with a precompression adjustment to limit movementwhen the system starts and stops and the air pressure builds upor dies off, as explained in the specification.

SPECIFICATION H

Hangers shall be manufactured withminimum characteristics as in SpecificationB, but without the neoprene element.Springs are seated in a steel washerreinforced neoprene cup that has aneoprene bushing projecting through the

bottom hole to prevent rod to hangercontact. Spring diameters and the lowerhole sizes, shall be large enough to allowthe hanger rod to swing through a 30 arcfrom side to side before contacting the cupbushing.

If ducts are suspended by flat strap iron, thehanger assembly shall be modified by themanufacturer with an eye on top of the boxand on the bottom of the spring hanger rodto allow for bolting to the hanger straps.Submittals on either of the above hangers

shall include a scale drawing of the hangershowing the 30 capability. Hangers for rodsshall be Type 30 or for straps W30 asmanufactured by Mason Industries, Inc.

SPECIFICATION I

When total air thrust exceeds 10% of theisolated weight, f loor mounted orsuspended air handling equipment shall beprotected against excessive displacementby the use of horizontal thrust restraints.The restraint shall consist of a modifiedSpecification B spring mounting. Restraintsprings shall have the same deflection asthe isolator springs. The assembly shall bepreset at the factory and fine tuned in thefield to allow for a maximum of 1/ 4(6mmmovement from stop to maximum thrust.The assemblies shall be furnished with rodand angle brackets for attachment to boththe equipment and duct work or theequipment and the structure. Restraintsshall be attached at the center line of thrustand symmetrically on both sides of the unit.Horizontal thrust restraints shall be WB asmanufactured by Mason Industries, Inc.

30 Hanger W30 Hanger

Obsolete1965WHS

Hanger

EYE BOLTS TOP ANDBOTTOM FOR HORIZONTALBOLTS TO FLAT STRAPS

RODS TOPAND BOTTOM

NEOPRENE SPRING CUPWITH PROJECTING RODISOLATION BUSHING

ASSEMBLY PLATE WITHNEOPRENE WASHER

EYE BOLT CAN SWING30 BEFORE CONTACTINGRESILIENT BUSHING

ROD CAN SWING30 BEFORE CONTACTINGRESILIENT BUSHING

RIGID STEEL FRAME

30

STEEL SPRINGS TOMATCH DEFLECTIONOF ISOLATORS

MOLDED NEOPRENE SPRINGCUP WITH INTEGRALNEOPRENE BUSHING

STEEL ANGLES WITHBACK-UP PLATES

PRECOMPRESSIONAND STOP NUT

THREADED RODWB Horizontal

Thrust Restraints

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BASES (SADDLES and BRACKETS)

A complete steel base is not required for equipment such asAbsorption Machines, Reciprocating Compressors, ShellMounted Centrifugal Compressors, H&V units, etc. Steelmembers improve stability, lower operating heights and in thecase of H&V units prevent distortion of sheet metal legs or baseangles. The use of saddles and brackets represents a costsaving compared to the complete bases in Specification J.We have called for Specification K in the SelectionGuide for all locations without J or L bases when Bor D mountings have 2 1 / 2(65mm) deflectionor more to improve appearance andreduce elevation. Never useindependent cross members inSeismic Zones, becauseof rotational failure. Alwaysuse complete bases.

BASES

Our very early specifications merely called for sufficient baserigidity to handle belt tension and keep the drive in alignment.There had been no criteria for base stiffness or design and everyvendor had his own version of what might be minimallyacceptable as there never was a unified code. Pump bases havetorque and bending problems that can ruin bearings, couplings

and pump seals. Before we extended pump bases to supportelbows, many installations were short circuited with suction anddischarge dog legs to the floor. We discussed this problem with anumber of structural people as well as acoustical specialists andfound that using beams with a depth equal to 1/10th of the spanis a good broad working rule that can be readily checked in thesubmittal stage. We have manufactured thousands of thesebases and find the design highly satisfactory as to appearance,rigidity and keeping base resonance high. The 14(350mm) limiton beam depth came about because experience has shown thatthe 1/10th requirement is too severe on very large bases. Forexample, in the 1965 specification, without this limitation, weencountered situations where the distance between chiller legswas twenty feet(6000mm). Thus, the specification was calling for24 inch(600mm) beams under a machine that already had greatstructural rigidity. In other situations, heating and ventilating unitsmight be as long as 15 feet(4500mm). Thus, it wouldseem that 18(450mm) beamsshould be used, but these werecompletely excessive as the wholeunit might only weigh eightthousand pounds(3636 kilo). The14(350mm) limitation makes thespecification more practical.


WF SteelBeam Base

SPECIFICATION K

Vibration isolation manufacturer shallprovide steel members welded to heightsaving brackets to cradle equipment havinglegs or bases that do not require acomplete supplementary base. Membersshall have sufficient rigidity to prevent

distortion of equipment. Inverted saddlesshall be type ICS, as manufactured byMason Industries, Inc.

SPECIFICATION J

Vibration isolation manufacturer shall furnishintegral structural steel bases. Rectangularbases are preferred for all equipment.Centrifugal refrigeration machines andpump bases may be T or L shaped. Pumpbases for split case pumps shall be largeenough to support suction and dischargeelbows. All perimeter members shall besteel beams with a minimum depth equal to1/10 of the longest dimension of the base.Base depth need not exceed 14(350mm)provided that the deflection andmisalignment is kept within acceptable limitsas determined by the manufacturer. Heightsaving brackets shall be employed in allmounting locations to provide a baseclearance of 1(25mm). Bases shall be type

WF as manufactured by Mason Industries,Inc.

RECTANGULARWELDED STRUCTURALSTEEL FRAME

HEIGHT SAVINGBRACKETS

WELDED STEELCROSS BRACING

BOLT HOLES ASREQUIRED

WELDED STRUCTURALSTEEL CROSS MEMBERS

HEIGHT SAVINGBRACKETS ICS Steel Beam Rails

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BASES

Concrete bases are recommended under pumps as they aremore rigid and a better choice in maintaining alignment. Theyneed not be selected for the additional mass that is neededunder highly unbalanced machines such as slow speedhorizontal or vertical compressors. If the building can handle theadded weight, floating concrete installations always look betterand the shielding reduces air borne noise transmission. The Kdesigns are a neat way of building these bases as thecontractor receives a complete package consisting of a steelform with reinforcing bars and anchor bolt templates in placeready for pouring. Concrete foundations need not have quite thesame depths as steel bases since stiffness is provided by theentire width. Therefore, we have reduced the depth requirementto 1/12th the longest dimension. We have limited the mandatorydepth to 12 inches(300mm), as compared to our olderspecification which had no depth limit. If the vibrationmanufacturer feels that the 12 inch depth is not sufficient, hemay increase it at his option. An open ended requirement of1/12th of the longest dimension led to thicknesses that werecompletely impractical on long bases where there was noparticular alignment, inertial or loading problem.

The steel form may be bolted or welded, structural or formedmetal if it does not deform during the pour. When the concretehardens, the structural strength and rigidity is provided by thereinforcement and has little or nothing to do with the perimetersteel.

SPECIFICATION L

Vibration isolation manufacturer shallfurnish rectangular steel concrete pouringforms for floating concrete bases. Bases forsplit case pumps shall be large enough toprovide support for suction and dischargeelbows. Bases shall be a minimum of 1/12of the longest dimension of the base but notless than 6(150mm). The base depth neednot exceed 12(300mm) unless specificallyrecommended by the base manufacturer formass or rigidity. Forms shall includeminimum concrete reinforcing consisting of1 / 2 (12mm) bars welded in place on6(150mm) centers running both ways in alayer 1 1/ 2 (40mm) above the bottom. Formsshall be furnished with steel templates tohold the anchor bolt sleeves and anchor

bolts while concrete is being poured. Heightsaving brackets shall be employed in allmounting locations to maintain a 1(25mm)clearance below the base. Wooden formedbases leaving a concrete rather then a steelfinish are not acceptable. Base shall betype BMK or K as manufactured by MasonIndustries, Inc.

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K Concrete Welded Base

BMK Concrete Bolted Base

Base Detail

BOLTED OR WELDEDSTEEL CONCRETE FORM

ANCHOR BOLIN SLEEVES A

REQUIRED

STEELREINFORCEMENT

HEIGHT SAVINGBRACKET

RECTANGULAR WELDEDSTRUCTURAL STEEL FRAME

HEIGHT SAVINGBRACKETS

BOLT HOLES ASREQUIRED

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CURB MOUNTED ALUMINUM BASESNOMINAL 1(25mm) DEFLECTION

Not too many years ago, cooling towers and curb mounted exhaustfans were the only pieces of mechanical equipment to be found onrooftops. This has all been changed as curb mounted airconditioning equipment is commanding a larger share of the market.While rooftop equipment manufacturers do what they can to isolatecomponents within their packages, their effectiveness is limited byshipping problems and available space as well as piping, electricaland fan connections. Unfortunately, many roofs are extremelysensitive to vibration and this makes the problem more difficult thancan be handled by the manufacturer's efforts.Curb mounted isolation bases must:1. Fit on top of manufacturers standard curbs and match the

underside of the isolated equipment2. Have wind and water seals that do not interfere with the spring

action.3. Resist wind forces and aging.4. Provide as much static spring deflection as practical.As with most of our products, all of these things had been done bycustom building bases in the field to solve existing problems and thisled to the design of our Curb Mounted Aluminum Base (TypeCMAB). We wasted a great deal of time with various friction andshear seals and we should have known better. All of our otherproducts never worked properly until we had a free standing springsystem and curbs were no exception.The SLF Spring Mountings are better than the type C telescopingcastings because the few inches of soft sponge guiding material inthe Type C often interferes with the action of the springs as happenswith all telescoping designs, regardless of manufacturer. In trying touse this method for sealing roof bases, some 16 to 60 lineal feet(4800mm to 7200mm) of sponge was needed for the perimeter andthe binding or freezing of the two members can completely bypassthe spring isolation. Therefore, we eliminated this method and ourweather seal is a truly flexible EPDM duct like seal rather than asliding or shear fit. As a secondary precaution, the upper aluminummember overlaps the lower and acts as a water shield.The main members of these bases are made of extruded aluminum,welded in the corners for weather-tightness. All of the steel springsare zinc electro plated or powder coated. Whenever practical, basesare shipped in one welded assembly to minimize assembly andinstallation time in the field. Where size does not permit one pieceshipment, we minimize the number of joints and furnish simplesplice kits.Horizontal wind resistance is provided by the horizontal springstability and supplementary rubber pads located between the twoframes in the corners. There is adequate clearance between upperand lower frames and the snubbers only act during high wind.Springs are selected from our standard A series with a ratedminimum deflection of 1(25mm) or more and 50% overtravel.Occasionally, we attain 1.5(32mm) deflection by using more of the

lightest springs in the series, but this is uneconomical except forvery light equipment. The suggested specification calls for minimum0.75(20mm) deflection as the manufacturer's weight and CG datamay be inaccurate and we do not wish to overstate the CMABcapability. While it would be desirable to use a higher deflectionseries than the 1(25mm) the design is limited by curb width andequipment contact problems. The use of taller springs having thesame diameter would lead to higher deflections on paper, but themuch lower horizontal stability and consequent rubbing would lowerrather than improve overall performance.CMAB curb mounted rooftop equipment bases are an excellent1(25mm) nominal 0.75(20mm) deflection tool and added insurancefor this type of installation on top of new buildings.CMAB curbs should not be used in seismic zones higher than 2A.

SPECIFICATION M

Curb mounted rooftop equipment shall bemounted on vibration isolation bases that fit overthe roof curb and under the isolated equipment.The ext ruded a luminum top member sha l loverlap the bottom to provide water runoffindependent of the seal. Aluminum membersshall house electro-galvanized or powder coated

springs selected for 0.75(20mm) minimumdeflection. Travel to solid shall be 1.5(40mm)minimum. Spring diameters shall be no less than0.8 of the spring height at rated load. Windres is tance sha l l be provided by means ofresilient snubbers in the corners with a minimumclearance of 1/ 4(6mm) so as not to interfere withthe spr ing ac t ion except in h igh winds .Manufacturer's self adhering closed cell spongegasketing must be used both above and belowthe base and a f lex ib le EPDM duct l ikeconnection shall seal the outside perimeter.Foam or o ther s l id ing or shear sea ls a reunacceptable in l ieu of the EPDM ductl ikec losure . Submit ta l s sha l l inc lude spr ingdeflect ions, spring diameters, compressedspring height and solid spring height as well asseal and wind resistance details. Curb mountedbases shall be Type CMAB as manufactured byMason Industries, Inc.

UnsuccessfulFriction andShear Seals

FLEXIBLE EPDMDUCT LIKE SEAL

CLOSED CELL SPONGETOP and BOTTOM

OVERLAP FORWATER RUNOFF

EXTRUDED ALUMINUMTOP AND BOTTOM

CMAB CurbMounted

AluminumBase

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COMPLETE ROOFTOP SPRING CURBS

In 1982 we showed the following method for increasingdeflection by suspending units from springs on top of a steelframe work and using the CMAB curb without springs as theseal.

There were 3 or 4 very successful installations, but the methodwas too cumbersome and expensive. We found the only answerwas to build a complete spring curb instead of just a cap on topof a standard curb. In our new complete curb the springs areadjustable from the outside so they can be changed if need beand the base can be leveled. Our standard deflections are0.75(20mm), 1 1/ 2(40mm) or 2 1/ 2(65mm) and occasionally asmuch as 4 1/ 2(112mm). They can be built to any height whenaccess doors are needed, and configured to provide level unitsupport, regardless of the slope of the roof. We started workingwith this design in 1988, and have had great success. It isOSHPD approved for seismic zones. The following sketch givesyou a broad idea of the construction. Please refer to the Base

section of the catalog for specific bulletins.

SPECIFICATION N

Curb mounted rooftop equipment shall bemounted on spring isolation curbs. Thelower member shall consist of a sheet metalZ section containing adjustable andremovable steel springs that support theupper floating section. The upper frame

must provide continuous support for theequipment and must be captive so as toresiliently resist wind forces. All directionalneoprene snubber bushings shall be aminimum of 1/ 4(6mm) thick. Steel springsshall be laterally stable and rest on1/ 4(6mm) thick neoprene acoustical pads.Hardware must be plated and the springsprovided with a rust resistant finish. Thecurbs waterproofing shall consist of acontinuous galvanized flexible counterflashing nailed over the lower curbswaterproofing and joined at the corners byEPDM bellows. All spring locations shallhave access ports with removablewaterproof covers. Lower curbs shall haveprovision for 2(50mm) of insulation. Curbshall be type RSC as manufactured byMason Industries, Inc.

Obsolete1982 Method

UPPER FLOATING

SUPPORT ASSEMBLY

LOWER STATIONARYASSEMBLY

GALVANIZED HAIRPINSPRING SEAL

HEAVY GAGE SHEETMETAL C SECTION

SPONGEAIR SEAL

SPRING SUPPORTEDTOP TUBE

CROSS BRACESON EACH SIDE OFINTERIOR WINDOWSWELDED INTO AN X

PROVISION FORINSULATION ANDSECURING ROOFWATERPROOFING

WINDOWS ARECOVERED AFTERADJUSTMENT

HEAVY GAGE SHEET METALZ SECTION

SPRINGSUPPORTS

RSC CompleteRooftop Spring

Curb

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FLEXIBLE RUBBER CONNECTORS

An old sales technique is the flexing of a hand held rubber or metallic hose toshow its flexibility. Nothing is limper than a rolled or folded canvas fire hose.However, when the hose is pressurized, it takes two men to bend and directit. All flexible connectors are stiff under pressure, and you can only expect somuch from them. They compensate for misalignment, relieve equipmentflange strain, provide comparative freedom for floating equipment onisolators, and relieve the equipment of pipeline weight. Flexible connectorsare a vital part of connections to equipment in seismic zones, as they will

allow large equipment excursions without rupture.Hose or rubber expansion joints reinforced with spiral wire or steel rings willnot reduce pipeline vibration at rpm, but only at rpm multiplied by the numberof blades in the pump wheel. Unfortunately, this frequency will continue topulse through the fluid, and generally regenerate the pipeline vibration on thefar side. In order to reduce noise and vibration at hydraulic frequency, a 2arch molded rubber expansion joint is the correct choice as the reinforcementis much like the sidewall of an automobile tire. There is no steel wire and theexpansion joint expands and contracts volumetrically at the hydraulicfrequency. This dissipates energy and reduces the noise and vibration asconfirmed by all of our acoustical tests. Spherical rubber connectors arepreferable in general, as they are more effective high frequency vibrationsound isolators and they do have the volumetric response capability notshared by metallic sections or wire reinforced hose.Our rubber hose specification has been upgraded over the years. 38 yearsago we suggested rubber flanged hoses without qualification other thanpressure and temperature capability. There were buckling problems and wefound that this type of hose was manufactured with an allowable elongation ofas much as 7% of its length (2(50mm) longer for a 30(750mm) section). Wechanged our specification to limit elongation to 1.25%. This was so costly werecommended installation of control cables to prevent excessive elongation.Unlike control rods, control cables are quite flexible transversely, and theassembly is manufactured with bridge bearing Neoprene bushings and0.5(12mm) thick neoprene washers of the proper area to limit loadings to amaximum of 1,000psi. Cables are a definite improvement over rigid controlrods, but they still tend to reduce the effectiveness of any rubber connector asaxial capabilities are limited. Fortunately, our rubber technology moved on.Modern spherical handbuilt molded rubber expansion joints are available forless than the cost of the ineffective rubber flanged hoses and far easier toinstall because of their short lengths.We developed the method of pre-extending the expansion joints by leaving agap that is longer than the nominal face to face dimension of the expansion

joint to allow for the predicted fixed elongation at a given pressure. Sincethere is a need for maximum volumetric expansion to eliminate noise, we arerecommending twin sphere molded expansion joints in all applications.In the past 25 years we have progressed from Neoprene to peroxide curedEPDM, because of greater temperature tolerance and resistance to ozoneand sunlight. Nylon reinforcement moved on to Polyester and then to Kevlar .Nylon will fatigue and fail at temperatures between 200F(93C) and250F(121C). We redesigned the mechanism for locking the raised facerubber flange behind the ductile iron flanges by building in a solid steel ringrather than the cable used by virtually all the other manufactures. With thiscombination of changed materials, we now had the safest and strongestrubber expansion joint on the market. However, there was still the possibilityof manufacturing errors no matter how few. Therefore, all Safeflex connectorsare factory tested to 150% of the rated pressure before shipment. (SeeSafeflex Development Bulletin SEJ-3 in the Hose section.)Test bulletins 901 and 902, show a 20db reduction in vibration acceleration inthe pipelines. This reduction in pipeline wall vibration, as well as thesmoothing of the fluid pulsation, lowered sound pressure levels in spaces farremoved from the pumps, but adjacent to the piping by 10 to 20db.These improvements peak at blade passage frequency where the vibratoryand noise problems are usually most troublesome. Therefore, thespecifications now include a requirement for a pre-tested product.This is the only specification where we urge you not to accept competitiveproducts unless they are manufactured with Kevlar reinforced high temperatureperoxide cured EPDM, and embedded rings rather than cable in the rubberraised face flanges. We would not have developed Safeflex if the otherconstruction were safe. We and all the other manufacturers had similar failuresprior to our redesign. We have not had a single failure out of the 30,000 unitssold in the two years since changing to the present Safeflex design.Even so, all expansion joints should be installed on the equipment side of theshut off valves and only in equipment rooms. It is not recommended that they

are installed out in the general structure in areas over finished ceilings, etc.

SPECIFICATION O

Rubber expansion joints shall be peroxide curedEPDM throughout with Kevlar t i re cordreinforcement. Substitutions must have certifiableequal or superior characteristics. The raised facerubber flanges must encase solid steel rings toprevent pul l out . Flexible cable wire is notacceptable. Sizes 1 1/ 2 through 14(40mm through350mm) shall have a ductile iron external ringbetween the two spheres. Sizes 16 through 24(400mm to 600mm) may be single sphere. Sizes3/ 4 through 2(20mm through 50mm) may haveone sphere, bolted threaded flange assemblies andcable retention.

Minimum ratings through 14(350mm) shall be250psi at 170F and 215psi at 250F. (1.72MPa at77C and 1.48MPa at 121C), 16(400mm) through24(600mm) 180psi at 170F and 150psi at 250F.(1.24MPa at 77C and 1.03 MPa at 121C). Higherpublished rated connectors may be used whererequired.

Safety factors shall be a minimum of 3/1. Allexpansion joints must be factory tested to 150% ofmaximum pressure for 12 minutes before shipment.The piping gap shall be equal to the length of theexpansion joint under pressure. Control rodspassing through 1/ 2(12mm) thick Neoprene washerbushings large enough to take the thrust at 1000psi(0.7 kg/mm 2) of surface area may be used onunanchored piping where the manufacturerdetermines the condition exceeds the expansion

joint rating without them. Submittals shall includetwo test reports by independent consultantsshowing minimum reductions of 20 DB in vibrationaccelerations and 10 DB in sound pressure levelsat typical blade passage frequencies on this or asimilar product by the same manufacturer. Allexpansion joints shall be installed on theequipment side of the shut off valves. Expansion

joints shall be SAFEFLEX SFDEJ, SFEJ, SFDCRor SFU and Control Rods CR as manufactured byMason Industries, Inc.

Safeflex DoubleArch SFDEJ

SafeflexReducerSFDCR

SafeflexSingleArchSFEJ

SOLID STEELNO ESCAPERETENTION RING

MOLDED INREINFORCING RING

INTERLOCKED DUCTILEIRON FLANGES

DUPONT KEVLAR TIRE CORDREINFORCEMENT WITH PEROXIDECURED EPDM (DuPont Nordel)THROUGHOUT

EnlargedWasher

Bushing

Control Rods CR

SafeflexThreadedFlange

SFU

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SPECIFICATION P

Flexible stainless steel hose shall have stainlesssteel braid and carbon steel fittings. Sizes3(75mm) and larger shall be flanged. Smallersizes may have male nipples. Minimum lengthsshall be as tabulated:

Rigid Flanged Male Nipples

3 x 14 (75 x 350mm

)1/ 2 x 9 (12 x 225

mm

4 x 15 (100 x 375mm ) 3/ 4 x 10 (19 x 250mm5 x 19 (125 x 475mm ) 1 x 11 (25 x 275mm6 x 20 (150 x 500mm ) 11/ 4 x 12 (32 x 300mm8 x 22 (200 x 550mm ) 11/ 2 x 13 (38 x 325mm

10 x 26 (250 x 650mm ) 2 x 14 (50 x 350mm12 x 28 (300 x 700mm ) 21/ 2 x 18 (64 x 450mm14 x 30 (350 x 750mm )16 x 32 (400 x 800mm )

At equipment, hoses shall be installed on theequipment side of the shut-off valves horizontaland parallel to the equipment shafts whereverpossible. Hoses shall be type BSS asmanufactured by Mason Industries, Inc.

SPECIFICATION R

All-directional acoustical pipe anchors, consistof two sizes of steel tubing separated by aminimum 1 / 2(12mm) thickness of 60 duro orsofter neoprene. Vertical restraint shall beprovided by similar material arranged to prevent

up or down vertical travel. Allowable loadson the isolation material shall not exceed500 psi(3.45 N/mm 2) and the design shallbe balanced for equal resistance in anydirection. All-directional anchors shall betype ADA as manufactured by MasonIndustries, Inc.

PIPE ANCHORS

In the 1982 publication we used our all directional anchor foranchorage or anchoring the ends of oversized clamps that allowedpiping to slide within the clamps. If the pipe was insulated, theclamps guided steel bars, welded to the pipe that protruded throughthe insulation. Those methods were a step forward. We continueanchoring but with welded gusseted brackets more commonly thanclamps at heavy anchor points.

The use of oversized clamps and steelsliding on steel was less satisfactory as ittended to generate noise and insulatingbetween the bars proved cumbersome.Therefore , we now use the ADA al ldirectional anchors in anchor locationsonly and resilient sliding guides asdescribed in Specification S to allow forexpansion or contraction.

We have standardized on this one multi-purpose all directional anchor forsimplicity of application and safety.


FLEXIBLE METALLIC HOSES

Rubber connectors are preferable for sound and vibrationattenuation, but careful consideration must be given to pressureand temperature limitations and location. Stainless steel hoses arerecommended for locations in ceilings or other construction awayfrom equipment rooms and for long life when temperatures exceed250F(121C) in continuous service. We are recommendingannular rather than helical construction for maximum flexibility in agiven length. While we can supply the very short so-called PumpConnectors, we are suggesting somewhat longer lengths forgreater offset and vibration tolerance.

WALL, FLOOR AND CEILING SEALS

Sealing noise within equipment rooms is a problem. One leakagepath is the space around piping passing through walls, floors orceilings. Field constructed seals made by packing fiberglass betweena sleeve and the pipe with a mastic seal on both ends may besatisfactory if carefully supervised. The quality will depend on the skillof the workmen, the centering of the pipe within the sleeve and theaccessibility of the entire pipe circumference.

A factory fabricated seal is much more positive. We suggest a splitseal with closed cell sponge rubber cemented to the two halves. Theinside is slightly smaller than the outside pipe diameter. When it isclamped around the body it provides a good tight seal. If

the piping goes in before the walls, clamp the seal aroundthe pipe and pour or build the walls around the outside. Ifthe walls are up first, drill or break the wall in the pipinglocations. Once the pipe has been hung, clamp the seal inplace and back pack concrete around the seal.

When temperatures are higher than those tolerated bysponge, fiberglass must be used as a reasonable substitute.

SPECIFICATION Q

Split Seals consist of pipe halves with minimum3/ 4(20mm) thick neoprene sponge cemented tothe inner faces. The seal shall be tightenedaround the pipe to eliminate clearance betweenthe inner sponge face and the piping. Concretemay be packed around the seal to make it integralwith the floor, wall or ceiling if the seal is not place prior to the construction of the buildinmember. Seals shall project a minimum o

1(25mm) past either face

the wall . Where tempeatures exceed 240F(115C), 10 lb. densifiberglass may be used in lieof the sponge. Seals shall beType SWS as manufacturedby Mason Industries, Inc.

BSS-RF RigidFlange Flexible

Stainless Steel Hose

BSS-MN MaleNipples Flexible

Stainless Steel Hose

SPLIT STEEL SLEEVE

HALVES ARE BOLTEDOR CLAMPEDAROUND PIPE

MINIMUM3/ 4(20mm)THICK CLOSED-CELLNEOPRENE SPONGELINER

SWS Wall Seal

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STEEL TUBING

BOLT OR WELD TOANCHOR BRACKET

BOLT OR WELDTO STRUCTURE

ALTERNAT

PIPE CLAWELDEDPIPE

ANCHOR

MAX. 60 DURONEOPRENEISOLATION(MINIMUM1/ 2(12mm) THICK)

VERTICAL RESTRAINT MAX. 60DURO NEOPRENE WASHER(MINIMUM1/ 2(12mm) THICK)MAX. LOADING 500 PSI

PREFERRED

BRACKETSWELDED TOPIPE

ANCHOR

ADA PipeAnchor

MN- END FITTINGSARE CARBON STEELMALE NIPPLES WITHNPT THREADS

TYPE 321STAINLESS

STEEL HOSEAND BRAID

RF- END FLANGES AREPLATE STEEL WITH150 LB. ASADRILLING

TYPE 321STAINLESS

STEEL HOSEAND BRAID

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RISER GUIDES

In 1982 we showed sliding guide locations using anchors under theends of oversized pipe clamps around the pipe or steel guide barswelded to the pipe. This was difficult because of the need to weldthe sliding bars to the pipe exterior and we found oversized clampswere not readily available. Perhaps the most discouraging part ofthe design was insulating between the guides and providing propercovering over the insulation. Therefore, we developed a new verticalsliding guide. This approach eliminates the sliding noise created bysteel on steel within the clamp. Our literature shows the guides setfor equal movements, but we can preset the guide toallow more movement upward or downward, as thecase may be. If presetting does not solvethe problem, the guide is manufacturedwith a longer body to accommodate thecondition. The method is better because itutilizes standard diameter clamps and theinsulation can be placed directly over theclamp with only the ends protruding to theguide. When piping is hot, the Neoprene inthe guide is protected, as there is asufficient temperature differential to theend of the clamp.


SPECIFICATION S

Pipe guides shall consist of a telescopicarrangement of two sizes of steel tubingseparated by a minimum 1/ 2(12mm) thicknessof 60 durometer or softer neoprene. The heightof the guides shall be preset with a shear pin toallow vertical motion due to pipe expansion orcontraction. Guides shall be capable of

1 5 / 8 (40mm) motion, or to meet locationrequirements. Pipe guides shall betype VSG as manufactured byMason Industries, Inc.

HORIZONTAL PIPE ISOLATION

The hanger, mounting and anchor discussions on the previous pagesinclude explanations of the various commodities and the reasons fortheir design. We have called for deflections in the first four supportsto be equal to that of the equipment as these locations often requirecapacities that are as great as the equipment loadings and thefrequencies and amplitudes are virtually the same as well. It wouldbe completely inconsistent to reduce these deflections immediately.After four hangers or approximately 30 feet(10m) the reduction inamplitude makes it feasible to use a more economical hanger.

(Note: Earlier specifications said three hangers. To move 30'(10m)from equipment normally requires four as the first supports the riser.)

Some specifications limit the application of hangers to theequipment room, 50 feet(15m) from equipment, etc., or someother formula based on a multiple of the diameter. They all try toreach out to a mythical location where the piping becomes Quiet.While it is usually true that the more severe vibration will occur closeto the equipment, the rest of the pipeline is likely to remaintroublesome. We have done expensive corrective work on pipesupports 20 stories away from the pumps and there is no way topredetermine if or where pipelines can be installed with solidsupports and not risk noise transmission,because of pipe or building resonance.Therefore, we are continuing to suggestcomplete pipeline isolation as hangers arerelatively inexpensive and worthwhileinsurance. Rubber expansion jointsminimize the noise problem at the source,but as explained in the ExplanationsSpecifications O and P, flex connectors dolittle or nothing to reduce vibration at RPM.

The specification calls for specificdeflections for piping suspended fromoccupied spaces if the machine room is inthe basement. The reason is the selectionguide calls for minimum floor isolation inbasements because there is normallynothing below them that is critical in anyway or the basement may be on grade. Ifthe hangers were to mimic thesedeflections, there would be a problem,because the piping may be suspendedfrom ceilings under sensitive areas.

SPECIFICATION T

The first four pipe hangers in the main lines nearthe mechanical equipment shall be as describedin specification Type G. Hangers supportingpiping 2(50mm) and larger in all other locationsthroughout the building shall be isolated byhangers as described in specification F. Floorsupported piping shall rest on isolators asdescribed in specification D. Heat exchangersand expansion tanks are considered part of thepiping run. The first four isolators from theisolated equipment shall have the same staticdeflection as specified for the mountings underthe connected equipment. If piping is connectedto equipment located in basements and hangs

from ceilings underoccupied spaces the firstfour hangers shall have0.75(20mm) deflection forpipe sizes up to andincluding 3(75mm), 1 1 / 2(40mm) deflection for pipesizes over 3(75mm) andup to and including6(150mm), and 2 1 / 2 (65mm) deflection there-after. Where piping con-nects to mechanicalequipment install speci-fication O expansion jointsor specification P stainlesshoses if O is not suitablefor the service. All pipingpassing through theequipment walls, floors orceilings shall be protectedagainst sound leakage bymeans of an acousticalseal, as described inSpecification Q.

VSG Riser Guides

Spec F30N

30

Spec GPC30N

Spec DSLRSpec Q SWS

30

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BOLT OR WELDTO CLAMP

BOLT OR WELDTO STRUCTURE

MAX. 60 DURONEOPRENEISOLATIONMINIMUM1/ 2(12mm)THICK

SHEAR PINFACTORY SET TOACCOMMODATEMOVEMENTS

ALTERNATE

BRACKETWELDED TOPIPE

PREFERRED

PIPE CLAMPWELDED TOPIPE

VERTICALSLIDINGGUIDE

VERTICALSLIDINGGUIDE

STEEL TUBING

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RISER ISOLATION

Riser isolation is simple in buildings up to 6 stories or so sincethermal expansion or contraction is a minor issue. It is often possibleto solve the problem by providing a single basement support andguides at the midpoint and roofline. If thermal motion is larger, anisolator in the center of the structure will allow for half motions in bothdirections. The application is completed with a few resilient guides.In high rise work the situation is entirely different. We often work with

massive risers where a single 20 story length is common. Singlerisers that run 40 stories or more are not that unusual. The thermaleffects become very important and the risers become so heavy that itis necessary to distribute the weight on a number of floors. When theisolation is not critical, there is still the structural problem. Once ananchor is established, the supports must be able to follow the motion.As the pipe expands, it will lift off simple devices, such as pads andshift the load to the lowest or lower stories. Should the pipe contract,it will lift off pads in the lower sections and transfer the load to thetop. Not allowing or considering this phenomena, has resulted instructural failure of the riser supports.A riser may be resiliently supported in the basement or on a columnthat is bolted to a basement pier. Assuming branch off connectionsare not a problem, and the horizontal run at the roof has allowed forexpansion, when the system expands, there is no structural problem

as none of the load rested on the intermediate floors to begin with.The same is true if the system contracts.In another example the pipe rises through a building where pipeclamps or brackets are used to transfer the load to successive floors.These attachments may or may not rest on isolation pads. When thesystem was installed at ambient temperature, all of the floorsassumed part of the load. When the system is filled with water, theremight be minor deflection in some of the floors to adjust to the slightlyshorter or longer length, but this higher load is still evenly distributed.However, if this is a hot water system with 2(50mm) expansion, thetop clamp would rise 2(50mm) above structure. At the mid point1(25mm), at the quarter point 0.5(12mm), etc. If there are no pads,the total load shifts to the lower 1 or 2 clamps immediately. If thereare pads, the load shifts completely as soon as it exceeds the smallinitial deflection of the upper pads and this leads to the structuralproblem.We are suggesting a safer system. Start ing with the sameparameters, it is always better to cut the motion at the two ends inhalf by establishing a neutral central resilient anchor. This anchorassumes no load. It is only there to direct the movement in the twodirections.Regardless of the length of the riser, there are an equal number ofsupports points, both above and below the anchor. An extremedesign would be a support on every floor, but commonly they are onevery third floor. These supports are selected with a minimumdeflection of 0.75(20mm), but four times the pipe travel at any givenlocation. Since the ends are moving 1(25mm) up at the top and1(25mm) down at the bottom, these mountings would have4(100mm) static deflection. Half way to the anchor, both top and

bottom, the movement would be 0.5(12mm) and the isolatordeflection 2(50mm). In this example these four mountings wouldhave enough capacity for the entire riser weight. That is why theneutral central anchor is not statically loaded.When the expansion takes place, the top hanger would lose 25% ofthe 4(100mm) deflection or 25% of its load and the mountingmidway to the top would experience the same proportionatephenomena. The two mountings below the anchor point would becompressed an additional 25% each, so there is a load shift of minus25% above and plus 25% below the anchor. Therefore the anchorlocation remains neutral. This load change of plus or minus 25% persupport location is minor and causes no difficulty.For a complete discussion, please refer to our Bulletin Riser-112 inthe Hangers, Piping Anchors, etc. section of the catalog. Thespecification reflects this system.

SPECIFICATION U

All vertical risers shall be supporteby spr ing i so la tors des igned tsupport the riser filled with water, iis a water line. Assigned loads musbe within the building design limat the support points. Neutral centraresilient anchors close to the cente

of the run shall direct movement uand down. The anchors shall becapable of holding an upward forcequal to the water weight when thsys tem is dra ined . I f one levecannot accommodate this forceanchors can be located on 2 or 3adjacent floors. Resilient guidesshall be spaced and sized properlydepending on the pipe diameter.Submittals must include the initialload, initial deflection, change indeflection, final load and change inload at all spring and anchor

support locations, as well as guidespacing. The initial spring deflectionshall be a minimum of 0.75(20mm)or four times the thermal movementat the isolator location, whichever isgreater. Calculations shall includepipe stress at end conditions andbranch off locations and themanufacturer must includeinstallation instructions. Submittalmust be stamped and signed by alicensed professional engineer inthe employ of the vibration vendorfor at least 5 years. Proper provision

shall be made for seismic protectionin seismic zones. The isolatormanufacturer shall be the same firmsupplying the mechanical contract.Support spring mountings shall beSpecification B, anchors Speci-fication R, telescoping guidesSpecification S.OPTIONAL ADDITION TO SPECIFICATION

The isolation vendor shall design and provide all brackets or clamps at riser spring guide and anchor locations. The contractor must install and adjust all isolators under the supervision of the isolator vendor or his representative.

Spec B SLF

Spec R ADA Spec S VSG

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DUCT ISOLATION

In general, duct hangers are limitedto a 50 foot(15m) requirement fromthe fans as the vibration becomesminimal as the air flow smooths out.Deflections are limited to 0.75(20mm) as these are light capacity

supports, and we are isolating sheetmetal resonance rather than the fan'sprimary disturbing frequency. Wecontinue to be concerned if the ductwork was designed for very highvelocity in which case the hangersare continued to the point where thisvelocity drops off.

SPECIFICATION V

All air ducts with a cross section of2ft2(0.19m 2) or larger shall be isolatedfrom the building structure byspecification H hangers or B floorsupports with a minimum deflection of0.75(20mm). Isolators shall continue

for 50(15m) from the equipment. If airvelocity exceeds 1000 fpm(5.3mps),hangers or supports shall continue foran additional 50(15m) or as shown onthe drawings.

SPECIFICATION WRITING

All of the specification paragraphs are generic in their descriptions and there is never any need to change thosedescriptions as they apply to all installations. If you have accepted our explanations and like our wording, yourspecification would appear exactly as shown starting on page 21. The paragraph sections are in the format of theAmerican Architectural Association. If this is not the format or the language you want to use, the specificationparagraphs can be readily rearranged or edited. Once these paragraphs are in place, there is no need to changethem from job to job or to omit or delete because the only isolators that are used are those that are called out onyour equipment schedule. In our presentation, Schedule 4.01 is part of the specification and it appears on page 27.If you prefer keeping this schedule as part of your drawings, in 4.01 write Equipment and Isolator schedule may befound in the drawings.

Schedule 4.01 is not really something you are adding. Most plans and specifications already have an equipmentschedule. The change is just the addition of the two columns which are headed Vibration Isolation. On the lefthandside we have a specification paragraph letter or letters, and on the right the static deflection. In most cases, thesame isolator is recommended for a class of equipment in all locations. However, depending on the size of theequipment, the sensitivity of the structure and the occupancy of the building, a deflection must be selected by youto best fit the particular project.

The selection guide that follows provides this information. HVAC equipment is listed on the left. We reference thevibration isolator by the first letter in the columns under Isolation and Deflection Criteria. The letters refer to thespecification paragraphs. The second letter may reference the paragraph on base configuration. When there arethree such letters, the first is always a vibration isolation device, the second the type of base, the third the type offlexible connector.

The next column over is the minimum isolator deflection in inches and millimeters. The two new columns on yourschedule completely describe the isolation package for any machine listed in the schedule. There are the letterdesignations that refer to the specification paragraphs, and then the deflection that is to be used with the isolationdevice.

There are five choices across. Up at the top under Isolation and Deflection Criteria there is a description of wherethe machinery will be located in terms of a ground supported slab or basement or an upper floor with a given floor

span. Most buildings have 30 foot(9 meter) floor spans, so most specifications are based on this deflection column.Should you have a 30 foot(9 meter) floor span, but it is a non-critical application, you might select from the 20foot(6 meter) column. Vibration reduction will be somewhat poorer, but the cost lower. If the span is 30 feet(9meter), but you are very concerned, you might make selections from the 40 foot(12 meter) column, because theadditional isolator deflection provides a higher vibration isolation safety factor. In general, the column showing theactual floor span is very conservative to begin with and needs no further consideration.

The table on page 17 is typical of how you would show your selections. Whether you require no isolation becausethe equipment is in a remote equipment room away from the building or it is something like a fire pump and you arenot concerned when it is in operation, you indicate no isolation by writing None in the chart. All the information inyour schedule is taken from the isolator selection guide. When using this method, you have the opportunity toconsider all of the equipment and there is little chance of leaving things out. On some jobs you will not to refer to allthe isolators, but it is much easier to leave them in than editing the specification each time. The only isolators thatare used are the ones that you include on your equipment schedule in the vibration isolation columns.

Spec H W30

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PUMP SCHEDULE Vibration Isolation

Pump Motor Specification Static DeflectionNo. Location Type HP (kw) Letters in (mm)

1 Penthouse Split Casing 75 (56) B-L-O 2.50 (65)

2 2nd Floor Close Coupled 0.5 (0.4) B-L-O 0.75 (20)

3 3rd Floor End Suction 10 (7.5) B-L-O 0.75 (20)

4 Basement Close Coupled 3 (2.0) A-O 0.35 (9)

5 Remote Basement Split Casing 50 (38) No Isolation

6 2nd Floor Fire Pump No Isolation

FAN SCHEDULE Vibration Isolation

Wheel Motor Isolator, Base, MinimumDiam. HP Restraint, Flexible Static

Fan Fan Connector DeflectionNo. Location in (mm) Arr. RPM HP (kw) Specification Letters in (mm)1 Penthouse 60 (1500) 1 SISW 503 30 (22) B-L 1.50 (40)

2 3rd Floor 49 (1245) 3 SISW 720 25 (19) B-L 0.75 (20)

3 Penthouse 73 (1850) 3 DIDW 405 75 (56) B-L 3.50 (90)

4 Basement 36 (900) 2 SISW 930 15 (11) A-J 0.35 (9)

5 3rd Floor 108 (2745) 3 SISW 400 125 (94) B-L 2.50 (65)

6 3rd Floor 2-27 (2-685) AC Unit * 533 10 (7.5) F 0.75 (20)7 Penthouse 3-12 (3-300) AC Unit 630 5 (4) B 0.75 (20)

COMPRESSOR SCHEDULE Vibration Isolation

Compressor Specification Static Defl. in (mm)No. Location Type Tonnage Letters or Frequency

1 Penthouse 500 Tons Centrifugal D-O 1.50 (40)

2 Penthouse 750 Tons Screw Comp. E-O 3 Hz

Below is a typical isolator schedule filled in.

4.01 Equipment Isolator Schedule

The information for the vibration isolation specification columns is found in the SpecificationSelection Guide pages 18 20. You need only reference the type of equipment and fill in the

appropriate specification letters and deflections based on the floor span in the equipmentslocation.

In the given example we are assuming that the floor spans are 30 ft.(9m) at all locations. Inyour application, use the proper floor span tabulation. You will note pump No. 5 has no isolationas it is in the basement under the garage where any transmitted vibration would annoy no one.Fire pumps (No. 6) are seldom isolated.

In preparing your specification this way you have an opportunity to consider every piece ofequipment, and there is very little possibility of your overlooking something in the rush of gettinga job completed.

Vibration Isolation Specification Columns

*Suspended

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SPECIFICATIONISOLATION AND DEFLECTION CRITERIA FORSELECTION GUIDE 4(100mm)THRU 6(150mm)THICK SOLID CONCRETE FLOORS (note 6)

o be used with Ground Supported 20(6m) Floor Span 30(9m) Floor Span 40(12m) Floor Span 50(15m) Floor SpanVibration Control Slab or Basement Possible Floor Possible Floor Possible Floor Possible FloorEngineering Specifications Defl .-0.67(17mm) Defl .-1.0(25mm) Defl. -1.33(34mm) Defl. -1.67(42mm )for HVAC Equipment inOffice Buildings, Colleges, Isol. Isol. Isol. Isol. Isol.Theatres and Similar Isolation Defl. Isolation Defl. Isolation Defl. Isolation Defl. Isolation Defl.Structures Spec. in(mm) Spec. in(mm) Spec. in(mm) Spec. in(mm) Spec. in(mm)

REFRIG. MACHINESAbsorption Machines A-O 0.35(9) D-O 0.75(20) D-O 0.75(20) D-O 1.5(40) D-O 1.5(40)Centrifugal Chillersor Heat Pumps

Cooler Condenser A-O 0.35(9) D-O 0.75(20) D-O 1.5(40) D-O 1.5(40) D-K-O 2.5(65)Mounted Hermetic or or orCompressors E*-O Max 3Hz E*-O Max 3Hz E*-K-O Max 3HzCooler Condenser A-O 0.35(9) D-O 0.75(20) D-O 1.5(40) D-O 1.5(40) D-O 2.5(65)Alongside Hermetic or or orCompressors E*-O Max 3Hz E*-O Max 3Hz E*-O Max 3HzOpen Drive Type A-J-O 0.35(9) D-J-O 0.75(20) D-J-O 1.5(40) D-J-O 1.5(40) D-J-O 2.5(65)Compressors (note 3) or or or

Refrig. Reciprocating E*-J-O Max 3Hz E*-J-O Max 3Hz E*-J-O Max 3HzCompressors

500 rpm to 750 rpm B 0.75(20) B 1.5(40) B 1.5(40) B-K 2.5(65) B-K 3.5(90)751 rpm and Over B 0.75(20) B 0.75(20) B or C* 1.5(40) B-K 2.5(65) B-K 3.5(90)

Reciprocating Chillers Max 3Hz or Max 3Hz or Max 3Hzor Heat Pumps C*-K C*-K

500 rpm to 750 rpm D-O 0.75(20) D-O 1.5(40) D-O 1.5(40) D-K-O 2.5(65) D-K-O 3.5(90)751 rpm and Over D-O 0.75(20) D-O 0.75(20) D-O 1.5(40) D-K-O 2.5(65) D-K-O 3.5(90)

PACKAGED STEAMGENERATIONS (Boilers) A-P 0.35(9) D-P 0.75(20) D-P 0.75(20) D-P 1.5(40) D-P 2.5(65)

PumpsClose Coupled

Thru 5hp (4kw) A-L-O 0.35(9) B-L-O 0.75(20) B-L-O 0.75(20) B-L-O 1.5(40) B-L-O 1.5(40)71/ 2 hp (5.6kw) and Larger B-L-O 0.75(20) B-L-O 0.75(20) B-L-O 1.5(40) B-L-O 1.5(40) B-L-O 2.5(65)

Base MountedThru 60hp (45kw) B-L-O 0.75(20) B-L-O 0.75(20) B-L-O 1.5(40) B-L-O 1.5(40) B-L-O 2.5(65)75hp (56kw) and Larger B-L-O 0.75(20) B-L-O 1.5(40) B-L-O 2.5(65) B-L-O 2.5(65) B-L-O 3.5(90)

or or orC*-L-O Max 3Hz C*-L-O Max 3Hz C*-L-O Max 3Hz

FACTORY ASSEMBLED

H & V UNITSFan Coil Units (Unit Heaters) F 0.75(20) F 0.75(20) F 0.75(20) F 0.75(20) F 0.75(20)Curb Mounted M 0.75(20) N 1.5(40) N 2.5(65) N 2.5(65)Roof Top UnitsSuspended Units (for FanHeads see Blowers Guide)

Thru 5hp (4kw) F 0.75(20) F 0.75(20) F 0.75(20) F 0.75(20) F 0.75(20)71/ 2 hp (5.6kw) and Larger F 1.5(40) F 1.5(40) F 1.5(40) F 1.5(40) F 1.5(40)275 rpm to 400 rpm71/ 2 hp (5.6kw) and Larger F 0.75(20) F 0.75(20) F 0.75(20) F 1.5(40) F 2.5(65)401 rpm and Over

Floor Mounted Units(for Fan Headssee Blowers Guide)

Thru 5hp (4kw) A 0.35(9) B 0.75(20) B 0.75(20) B 0.75(20) B 0.75(20)71/ 2 hp (5.6kw) and Larger A 0.35(9) B 1.5(40) B 1.5(40) B 1.5(40) B 1.5(40)275 rpm to 400 rpm71/ 2 hp (5.6kw) to 40hp A 0.35(9) B 0.75(20) B 0.75(20) B 1.5(40) B-K 2.5(65)401 rpm and Over50hp (38kw) and Larger A 0.35(9) B 0.75(20) B 1.5(40) B-K 2.5(65) B-K 3.5(90)401 rpm and Over

AIR COMPRESSORTank Mounted Type B-L-P 0.75(20) B-L-P 0.75(20) B-L-P 1.5(40) B-L-P 2.5(65) B-L-P 3.5(90)V - W Type B-L-P 0.75(20) B-L-P 0.75(20) B-L-P 1.5(40) B-L-P 2.5(65) B-L-P 3.5(90)

Horz, Vert, 1 or 2 Cylinders(note 4)275 rpm to 499 rpm B-L -P 2.5(65) B-L -P 2.5(65) B-L -P 2.5(65) B-L -P 3.5(90) B-L -P 3.5(90)500 rpm to 800 rpm B-L -P 1.5(40) B-L -P 1.5(40) B-L -P 2.5(65) B-L -P 3.5(90) B-L -P 3.5(90)

L Specification in this section only should read L type inertia bases with sufficient massto limit motion to a theoretical double amplitude of 0.03(.7mm)

*NOTE: Isolators in Red are Air Springs recommended for highly critical locations.

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SPECIFICATIONISOLATION AND DEFLECTION CRITERIA FORSELECTION GUIDE (contd) 4(100mm)THRU 6(150mm)THICK SOLID CONCRETE FLOORS (note 7)

to be used with Ground Supported 20(6m) Floor Span 30(9m) Floor Span 40(12m) Floor Span 50(15m) Floor SpanVibration Control Slab or Basement Possible Floor Possible Floor Possible Floor Possible FloorEngineering Specifications Defl .-0.67(17mm) Defl. -1.0(25mm) Defl.-1.33(34mm) Defl. -1.67(42mmfor HVAC Equipment inOffice Buildings, Colleges, Isol. Isol. Isol. Isol. Isol.Theatres and Similar Isolation Defl. Isolation Defl. Isolation Defl. Isolation Defl. Isolation Defl.Structures Spec. in(mm) Spec. in(mm) Spec. in(mm) Spec. in(mm) Spec. in(mm)

BLOWERS Engineering Specifications and Minimum Static Deflection

Utility Sets as tabulated below (note 1)

Spec B for 0.75(20mm) and 1.5(40mm) deflection and Spec B-L forFloor Mounted (note 5) A 0.35(9) over 1.5(40mm) deflection with deflection from Blower Minimum Deflection

Guide below, but not to exceed 2.5(65mm)

Spec B-L with deflection from Blower Minimum Deflection Guide below. IfRoof Mounted roof will not handle concrete base load use Spec D for 0.75(20mm) and

1.5(40mm) deflection and Spec D-K for over 1.5(40mm) deflection.

Suspended Unit (note 5) Spec F with deflection from Blower Minimum Deflection Guide below, notto exceed 2.5(65mm) deflection.

Centrifugal Blowers (note 6) A-L 0.35(9) Spec B-L with def lection from Blower Minimum Deflection Guide below.

Fan Heads (HVAC UnitBlower Section Only)

Spec B-I if 0.75(20mm) or 1.5(40mm) deflection or Spec B-K-IFloor Mounted A-I 0.35(9) for deflection over 2.5(65mm) to 4.5(115mm) from Blower Minimum

Deflection Guide below.

Suspended Units Spec F-I with deflection from Blower Minimum Deflection Guide below.

Tubular Centrifugaland Axial Fans

Suspended Units Spec F with deflection from Blower Minimum Deflection Guide below,Spec F-I for over 4(100) static pressure.

Floor Mounted with Motor Spec B for 0.75(20mm) and 1.5(40mm) deflection and Spec B-K-I for

on/in Fan Casing A 0.35(9) 2.5(65mm) to 4.5(115mm) deflect ion with def lection from Blower MinimumDeflection Guide below, Spec B-L-I or B-I for over 4(100mm) static pressure.

Floor MountedArrangement 1 or any A-L 0.35(9) Spec B-L with deflection from Blower Minimum Deflection Guide below.

Separately Mounted Motor

COOLING TOWERS & A 0.35(9) Spec D or E* with deflection from Blo

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