USACE / NAVFAC / AFCESA / NASA UFGS-23 05 48 (August 2008)
--------------------------------
Preparing Activity: NASA Superseding
UFGS-23 05 48.00 40 (April 2008)
UNIFIED FACILITIES GUIDE SPECIFICATIONS
References are in agreement with UMRL dated January 2009
SECTION 23 05 48
VIBRATION AND SEISMIC CONTROLS FOR HVAC PIPING AND EQUIPMENT
08/08
NOTE: This specification covers the requirements for vibration-isolation systems
for air-conditioning equipment.
Provisions of the following specifications should be coordinated with equipment
selection, specifications, and the drawings.
For equipment speeds under 250 revolutions per minute (rpm), special consideration
is required.
This specification is arranged to be used in either of the following two ways:
The part entitled, "Vibration-Isolation Systems Application," and selected or
rewritten text thereunder may be published as part of the bound specification.
Drawing schedules shall include applicable data listed under Part 2.
Or, the part entitled, "Vibration Isolation-Systems Application," may be deleted
when required applicable content is scheduled on the drawings.
Drawing schedules shall include the following data: equipment number; mass
of inertia block if different from that specified or if not specified; minimum
number of isolators for complex applications; lowest equipment rpm; impeller
size; power; isolation provisions in the form of "C-CIB-1.75" which includes
mounting, base, and minimum deflection in millimeter inches. This method is
recommended in view of anticipated need to rewrite or supplement this basic
specification to ensure suitability of provisions for specific project applications.
Edit this guide specification for project specific requirements by adding, deleting,
or revising text. For bracketed items, choose applicable items(s) or insert
appropriate information.
Remove information and requirements not required in respective project, whether
or not brackets are present.
Comments and suggestions on this guide specification are welcome and should
be directed to the technical proponent of the specification. A listing of technical
proponents, including their organization designation and telephone number, is
on the Internet.
Recommended changes to a UFGS should be submitted as a Criteria Change Request
(CCR).
PART 1 GENERAL
1.1 REFERENCES
NOTE: This paragraph is used to list the publications cited in the text of
the guide specification. The publications are referred to in the text by basic
designation only and listed in this paragraph by organization, designation,
date, and title.
Use the Reference Wizard's Check Reference feature when you add a RID outside
of the Section's Reference Article to automatically place the reference in the
Reference Article. Also use the Reference Wizard's Check Reference feature
to update the issue dates.
References not used in the text will automatically be deleted from this section
of the project specification when you choose to reconcile references in the
publish print process.
The publications listed below form a part of this specification to the extent referenced. The publications are
referred to within the text by the basic designation only.
[ACOUSTICAL SOCIETY OF AMERICA (ASA)ASA S2.40(1984; R 2001) Mechanical Vibration of Rotating and Reciprocating Machinery - Requirements for Instruments for Measuring Vibration SeverityASA S2.71(1983; R 2006) Guide to the Evaluation of Human Exposure to Vibration in Buildings][AMERICAN SOCIETY OF HEATING, REFRIGERATING AND AIR-CONDITIONING ENGINEERS (ASHRAE)ASHRAE HVAC APP IP HDBK(2007) HVAC Applications Handbook, I-P EditionASHRAE HVAC APP SI HDBK(2007) HVAC Applications Handbook, SI Edition][NATIONAL ENVIRONMENTAL BALANCING BUREAU (NEBB)NEBB PROCEDURAL STANDARDS(2005) Procedural Standards for TAB (Testing, Adjusting and Balancing) Environmental Systems]1.2 GENERAL REQUIREMENTS
NOTE: If Sections 23 00 00 AIR SUPPLY, DISTRIBUTION, VENTILATION, AND EXHAUST
SYSTEMS and Section 23 05 15 COMMON PIPING FOR HVAC are not included in the
project specification, applicable requirements therefrom should be inserted
and the following paragraphs deleted. Vibration isolation considerations for
systems other than A/C equipment should be addressed in each respective section.
Section 23 00 00 AIR SUPPLY, DISTRIBUTION, VENTILATION, AND EXHAUST SYSTEMS applies to work specified in this
section to the extent applicable.
Section 23 05 15 COMMON PIPING FOR HVAC applies to work specified in this section to the extent applicable.
All vibration-control apparatus must be the product of a single manufacturing source, where possible. Human
exposure levels should be considered using ASA S2.71 and NEBB PROCEDURAL STANDARDS.
NOTE: Select the following paragraphs if text under "Vibration-Isolation Systems
Application" is deleted and required isolation provisions are scheduled on the
drawings.
Scheduled isolation mounting is in millimeter inches and is a minimum static deflection.
Spans referred to in Part 2, "Vibration-Isolation Systems Application," must mean longest bay dimension.
Determine exact mounting sizes and number of isolators by the isolator manufacturer based on equipment that will
be installed. Check equipment revolutions per minute (rpm) and spring deflections to verify that resonance cannot
occur.
Installation Drawings for vibration isolator systems must include equipment and performance requirements.
Indicate within Outline Drawings for vibration isolator systems overall physical features, dimensions, ratings,
service requirements, and weights of equipment.
Equipment and Performance Data for vibration isolator systems must include equipment base design; inertia-block
mass relative to support equipment weight; spring loads and free, operating, and solid heights of spring; spring
diameters; nonmetallic isolator loading and deflection; disturbing frequency; natural frequency of mounts; deflection
of working member; and anticipated amount of physical movement at the reference points.
1.3 SUBMITTALS
NOTE: Review Submittal Description (SD) definitions in Section 01 33 00 SUBMITTAL
PROCEDURES and edit the following list to reflect only the submittals required
for the project. Submittals should be kept to the minimum required for adequate
quality control.
A “G” following a submittal item indicates that the submittal requires Government
approval. Some submittals are already marked with a “G”. Only delete an existing
“G” if the submittal item is not complex and can be reviewed through the Contractor’s
Quality Control system. Only add a “G” if the submittal is sufficiently important
or complex in context of the project.
For submittals requiring Government approval on Army projects, a code of up
to three characters within the submittal tags may be used following the "G"
designation to indicate the approving authority. Codes for Army projects using
the Resident Management System (RMS) are: "AE" for Architect-Engineer; "DO"
for District Office (Engineering Division or other organization in the District
Office); "AO" for Area Office; "RO" for Resident Office; and "PO" for Project
Office. Codes following the "G" typically are not used for Navy, Air Force,
and NASA projects.
Choose the first bracketed item for Navy, Air Force and NASA projects, or choose
the second bracketed item for Army projects.
Government approval is required for submittals with a "G" designation; submittals not having a "G" designation
are [for Contractor Quality Control approval.][for information only. When used, a designation following the
"G" designation identifies the office that will review the submittal for the Government.] Submit the following
in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:
SD-02 Shop Drawings
Submit Installation Drawings and Outline Drawings in accordance with paragraph entitled, "General
Requirements," of this section.
SD-03 Product Data
Submit Equipment and Performance Data in accordance with paragraph entitled, "General Requirements,"
of this section.
Submit Manufacturer's catalog data for the following items:
Mountings
Bases
Isolators
Floor-Mounted Piping
Vertical Piping
SD-06 Test Reports
Submit test reports for deflection tests in accordance with the paragraph entitled, "Type of
Vibration-Isolation Provisions," of this section. Include within reports the following information:
Type of Isolator
Type of Base
Allowable Deflection
Measured Deflection
PART 2 PRODUCTS
2.1 TYPE OF VIBRATION-ISOLATION PROVISIONS
NOTE: Use only those standards as necessary.
Design for vibration isolation using [NEBB PROCEDURAL STANDARDS] [ASHRAE HVAC APP SI HDBK, ASHRAE HVAC APP IP HDBK
, Chapter 37,] as applicable to the following sections.
Test reports for testing vibration isolation must be submitted for each Type of Isolator and each Type of Base
, and meet referenced standards contained within this section. Include in test reports Allowable Deflectionand
Measured Deflection also meeting referenced standards within this section.
2.1.1 Materials
Rubber must be natural rubber. Elastomer must be chloroprene. Shore A durometer measurement of both materials
and range between 40 and 60.
Inorganic materials such as precompressed, high-density, fibrous glass encased in a resilient moisture-impervious
membrane may be used in lieu of specified natural rubber and elastomers. Where this substitution is made, specified
deflections must be modified by the manufacturing source to accommodate physical characteristics of inorganic
materials and to provide equal or better vibration isolation.
Weather-exposed metal vibration-isolator parts must be corrosion protected. Chloroprene coat springs.
2.1.2 Mountings
Mountings must be:
[Type A: Composite pad, with 6.3 millimeter 0.25-inch thick elastomer top and bottom layers, molded
to contain a pattern with nonslip characteristics in all horizontal directions. Elastomer loading must
not exceed 275 kilopascal 40 pounds per square inch (psi). Minimum overall thickness must be 25 millimeter
1 inch. Maximum deflections up to 6.3 millimeter 0.25-inch are allowed.]
[Type B: Double [rubber-in-shear] [elastomer-in-shear] with molded-in steel reinforcement in top and
bottom. Maximum deflections up to 12.7 millimeter 0.50 inch are allowed.]
[Type C: Free-standing laterally stable open-spring type for deflections over 12.7 millimeter 0.50 inch
, with built-in bearing and leveling provisions, 6.3 millimeter 0.25-inch thick Type A base elastomer
pads, and accessories. Outside diameter of each spring must be equal to or greater than 0.9 times the
operating height of the spring under rated load.]
[Type D: Partially housed type, containing one or more vertically restrained springs with at least 12.7
millimeter 0.50 inch clearance maintained around springs, with adjustable limit stops, 6.3 millimeter
0.25-inch thick Type A base elastomer pads, and accessories.]
[Type E: Pendulum-suspension configuration with free-standing stable spring with resilient horizontal
and vertical restraints to allow maximum movements of 6.3 millimeter 0.25 inch in each direction, 6.3
millimeter 0.25-inch thick Type A base elastomer pads.]
[Type F: Combination [spring and rubber-in-shear] [elastomer-in-shear] steel framed for hanger-rod mounting.
Minimum total static deflection must be 25 millimeter 1 inch.]
NOTE: Use air springs where springs are not practical. Consider use where
spring deflection exceeds 89 millimeter 3.5 inches. Mount equipment on type
base with "outrigger" brackets. Detail dependable air supply and connection
provisions including hose connections where necessary.
Servo-controlled air spring isolators with natural frequencies for most applications
can be provided. System loads can range from 227 to 226,796 kilogram 500 to
500,000 pounds. Servo-mechanisms will maintain height of isolated mass within
0.13 millimeter 0.005 inch.
[Type G: Air spring with body constructed of reinforced elastomer specifically suitable for application environment.
Select air spring to provide a natural frequency equal to 127 millimeter 5 inches of deflection of conventional
specified steel springs. Provide facilities for dead-level adjustment and height-control of supported equipment.]
2.1.3 Bases
Bases must be:
[Type U: Unit isolators without rails, structural-steel bases, or inertia blocks.]
[Type R: Rails, [connected] [disconnected] mill-rolled structural steel, of sufficient dimension to
preclude deflection at midpoint of unsupported span in excess of 1/1,440th of the span between isolators,
power transmission, component misalignment, and any overhung weight. Where Type R bases are specified
and the equipment proposed requires additional base support, use a Type S base.]
[Type S: Structural-steel bases common to a supported assembly, made from welded-joint mill-rolled structural
steel with closed-perimeter configuration, isolators attached to outrigger supports.]
Height of steel members must be sufficient to provide stiffness required to maintain equipment manufacturer's
recommended alignment and duty efficiency of power-transmission components. Height of steel member must
not result in member deflection at midpoint of unsupported span of more than 1/1,440th of the span between
isolators. Minimum height must be 127 millimeter 5 inches.
NOTE: The following concrete inertia-block thickness and mass criteria are
of necessity, general in scope and should be reviewed for each application and
rewritten to reflect specific job conditions.
Mass of inertia block may range from one to three times the weight of supported
equipment. Usually a 1 to 1 ratio is satisfactory and 1-1/2 to 1 ratio is not
unusual. It is very difficult to achieve an equal weight between equipment
and inertia base on air-handling units, especially where they may be large size.
Due to more complex forming and isolator construction required, blocks with
recessed isolator-mounting provisions are more expensive and should be specified
only to eliminate hazard to personnel.
[Type CIB: Concrete inertia blocks must be common to the entire assembly, and have welded-joint construction,
mill-rolled structural-steel perimeters, welded-in No. 4 reinforcing bars 200 millimeter 8 inches on
center each way near the bottom of the block, outrigger-isolator mounting provisions, anchor bolts, and
be filled with 20.68 Megapascal 3,000 psi cured-strength concrete.]
Configuration of inertia bases must be rectangular to accommodate equipment supported.
Minimum thickness of inertia base, in addition to providing suitable mass, must be sufficient to provide
stiffness to maintain equipment manufacturer's recommended alignment and duty efficiency of power-transmission
components. Minimum thickness must be sufficient to result in base deflection at midpoint of unsupported
span of not more than 1/1,440th of the span between isolators. Minimum thickness, the preceding requirements
not withstanding, must be 8 percent of the longest base dimension.
NOTE: Pump bases should be as stiff as practical. 300 millimeter 12-inch thick
bases are common. To attain stiffness, mass to 1-1/2 times weight of assembly
may be considered. Modify thickness in the following paragraph as required.
Pumps with flexible couplings must not have inertia bases less than 200 millimeter 8 inches thick.
Minimum mass of concrete inertia block must be equal in weight to supported equipment.
2.2 VIBRATION-ISOLATION SYSTEMS APPLICATION
Vibration isolation design per [NEBB PROCEDURAL STANDARDS] [ ASHRAE HVAC APP SI HDBK,ASHRAE HVAC APP IP HDBK,
Chapter 37,] [ASA S2.40].
NOTE: The following empirical recommendations are based on floors 102 to 152
millimeter 4 to 6 inches thick and without subbase or "housekeeping" pad. Spring
deflections may be reduced for floors which are 200 millimeter 8 inches thick.
"Basement below grade" is considered as on "undisturbed earth." "On grade"
is considered as on some fill.
Review "provisions" for each application.
Where isolator deflection is specified for inside locations and project equipment
application is roof-mounted and weather-exposed; add 13 millimeter 1/2 inch
to specific deflection, use Type D isolators and type U, R, or S bases.
Reciprocating compressor-condenser (rcc) criteria are for inside location, with
water-cooled condenser integrally mounted.
Extreme care should be used in isolating field-erected cooling-tower mechanical-equipment
supports. Too much mechanical-equipment support movement may reduce propeller
to fan ring clearance, normally about 13 millimeter 1/2 inch, to 0. Type U
isolators cannot be used on certain units because construction may be such that
adequately spaced support points are not available. Recommendations specified
are for package units only. Review all structural-steel supports and vibration-isolation
provisions with cooling-tower and vibration-isolator manufacturers for field-erected
cooling towers with mountings to be applied as follows:
Type A under basin alone which may suffice in 50 percent of cases
Type D the under basin or structural-steel supports only, with deflections similar
to those specified for package tower springs
Type E under mechanical-equipment supports with Type A under basin 75 to 100
millimeter 3 to 4 inch Type E deflection
Wherever practical, avoid putting pumps on vibration isolators.
Where deflections exceed 90 millimeter 3.5 inches, consider air springs
2.2.1 Centrifugal Water Chiller Package Locations
ON GRADE ON GRADE ON GRADE
BASEMENT 6096 MM 9144 MM 12192 MM
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
Hermetic A-U-6.3 B-U-13 D-S-44.5 D-S-63
Open Type B-U-9.7 D-U-25 D-CIB-44.5 D-CIB-63
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN MILLIMETER
ON GRADE ON GRADE ON GRADE
BASEMENT 20-FOOT 30-FOOT 40-FOOT
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
Hermetic A-U-0.25 B-U-0.50 D-S-1.75 D-S-2.5
Open Type B-U-0.38 D-U-1.0 D-CIB-1.75 D-CIB-2.5
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN INCHES
2.2.2 Reciprocating Water Chiller Package Locations
ON GRADE ON GRADE ON GRADE
BASEMENT 6096 MM 9144 MM 12192 MM
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
500 to
750 rpm D-U-25 D-U-38 D-S-63 D-CIB-69
750 rpm
and over D-U-25 D-U-25 D-R-50 D-CIB-63
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN MILLIMETER
ON GRADE ON GRADE ON GRADE
BASEMENT 20-FOOT 30-FOOT 40-FOOT
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
500 to
750 rpm D-U-1.0 D-U-1.5 D-S-2.5 D-CIB-2.75
750 rpm
and over D-U-1.0 D-U-1.0 D-R-2.0 D-CIB-2.5
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN INCHES
2.2.3 Absorption Water Chiller Package Locations
ON GRADE ON GRADE ON GRADE
BASEMENT 6096 MM 9144 MM 12192 MM
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
Standard A-U-6 D-U-25 D-U-38 D-U-69
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN MILLIMETER
ON GRADE ON GRADE ON GRADE
BASEMENT 20-FOOT 30-FOOT 40-FOOT
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
Standard A-U-0.25 D-U-1.0 D-U-1.5 D-U-2.75
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN INCHES
2.2.4 Reciprocating Compressor/Condenser Locations
ON GRADE ON GRADE ON GRADE
BASEMENT 6096 MM 9144 MM 12192 MM
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
500 to
750 rpm D-U-25 D-U-38 D-U-63 D-CIB-69
750 to
and over D-U-25 D-U-25 D-U-50 D-CIB-63
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN MILLIMETER
ON GRADE ON GRADE ON GRADE
BASEMENT 20-FOOT 30-FOOT 40-FOOT
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
500 to
750 rpm D-U-1.0 D-U-1.5 D-U-2.5 D-CIB-2.75
750 to
and over D-U-1.0 D-U-1.0 D-U-2.0 D-CIB-2.5
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN INCHES
2.2.5 Reciprocating Refrigeration Compressor Locations
ON GRADE ON GRADE ON GRADE
BASEMENT 6096 MM 9144 MM 12192 MM
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
500 to
750 rpm C-U-25 C-U-38 C-U-63 C-CIB-69
750 rpm
and over C-U-25 C-U-25 C-U-50 C-CIB-63
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN MILLIMETER
ON GRADE ON GRADE ON GRADE
BASEMENT 20-FOOT 30-FOOT 40-FOOT
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
500 to
750 rpm C-U-1.0 C-U-1.5 C-U-2.5 C-CIB-2.75
750 rpm
and over C-U-1.0 C-U-1.0 C-U-2.0 C-CIB-2.5
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN INCHES
2.2.6 Centrifugal Pump Locations
ON GRADE ON GRADE ON GRADE
BASEMENT 6096 MM 9144 MM 12192 MM
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
Close-
couple
through
3728 watt None -R-8.9 C-S-25 C-S-25
Bedplate-
mounted
through
3728 watt None C-CIB-25 C-CIB-38 C-CIB-44.5
5592 watt None C-CIB-25 C-CIB-44.5 C-CIB-44.5
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN MILLIMETER
ON GRADE ON GRADE ON GRADE
BASEMENT 20-FOOT 30-FOOT 40-FOOT
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
Close-
couple
through
5 hp None -R-0.35 C-S-1.0 C-S-1.0
Bedplate-
mounted
through
5 hp None C-CIB-1.0 C-CIB-1.5 C-CIB-1.75
7-1/2 hp None C-CIB-1.0 C-CIB-1.75 C-CIB-2.5
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN INCHES
2.2.7 Air-Cooled Condensing Unit Locations
6096 MM 9144 MM 12192 MM
ROOF-SPAN ROOF-SPAN ROOF-SPAN
TYPE EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS*
Through 5 hp
over 900 rpm B-U-13 D-U-25 D-U-44.5
Over 5 hp
to 500 rpm B-U-13 D-U-44.5 D-U-63
500 rpm and over B-U-13 D-U-25 D-U-44.5
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN MILLIMETER
20-FOOT 30-FOOT 40-FOOT
ROOF-SPAN ROOF-SPAN ROOF-SPAN
TYPE EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS*
Through 5 hp
over 900 rpm B-U-0.5 D-U-1.0 D-U-1.75
Over 5 hp
to 500 rpm B-U-0.5 D-U-1.75 D-U-2.5
500 rpm and over B-U-0.5 D-U-1.0 D-U-1.75
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN INCHES
2.2.8 Low-Pressure Suspended Air-Handling Unit (AHU) Locations
Vibration-isolation provisions apply to ceiling-suspended Air Moving and Conditioning Association Class A packaged
central-station units.
6096 MM 9144 MM 12192 MM
ROOF-SPAN ROOF-SPAN ROOF-SPAN
TYPE EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS*
Through 3728 watt F-U-25 F-U-25 F-U-25
5592 watt and over
250 to 500 rpm F-U-44.5 F-U-44.5 F-U-44.5
500 rpm and over F-U-25 F-U-31.8 F-U-39.4
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN MILLIMETER
20-FOOT 30-FOOT 40-FOOT
ROOF-SPAN ROOF-SPAN ROOF-SPAN
TYPE EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS*
Through 5 hp F-U-1.0 F-U-1.0 F-U-1.0
7-1/2 hp and over
250 to 500 rpm F-U-1.75 F-U-1.75 F-U-1.75
500 rpm and over F-U-1.0 F-U-1.25 F-U-1.55
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN INCHES
2.2.9 Low-Pressure AHU Locations
Vibration-isolation provisions apply to floor-mounted Air Moving and Conditioning Association Class A packaged
central-station units.
ON GRADE ON GRADE ON GRADE
BASEMENT 6096 MM 9144 MM 12192 MM
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
Through
3728 watt B-U-8.9 C-U-25 C-U-25 C-U-25
5592 watt
and over
250 to
500 rpm B-U-8.9 C-U-44.5 C-U-44.5 C-U-44.5
500 rpm B-U-8.9 C-U-25 C-U-38
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN MILLIMETER
ON GRADE ON GRADE ON GRADE
BASEMENT 20-FOOT 30-FOOT 40-FOOT
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
Through
5 hp B-U-0.35 C-U-1.0 C-U-1.0 C-U-1.0
7-1/2 hp
and over
250 to
500 rpm B-U-0.35 C-U-1.75 C-U-1.75 C-U-1.75
500 rpm B-U-0.35 C-U-1.0 C-U-1.5
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN INCHES
2.2.10 Medium- And High-Pressure Ahu Locations
Vibration-isolation provisions apply to floor-mounted Air Moving and Conditioning Association Classes B and C
packaged central-station units.
ON GRADE ON GRADE ON GRADE
BASEMENT 20-FOOT 30-FOOT 40-FOOT
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
Through
20 hp
250 to
300 rpm B-U-0.35 C-U-2.5 C-U-2.5 C-U-3.5
300 to
500 rpm B-U-0.35 C-U-1.75 C-U-1.75 C-U-2.5
500 rpm
and over B-U-0.35 C-U-1.0 C-U-1.0 C-U-1.75
Over 20 hp
250 to
300 rpm B-U-0.35 C-U-2.5 C-CIB-3.5 C-CIB-3.5
300 to
500 rpm B-U-0.35 C-U-2.5 C-CIB-2.5 C-CIB-3.5
500 rpm
and over B-U-0.35 C-U-1.0 C-CIB-1.75 C-CIB-2.5
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN INCHES
2.2.11 Air-Moving Device Locations
Vibration-isolation provisions apply to [housed] [unhoused] free-standing fans of any pressure rating, located
in [field-erected [field-] [factory-] fabricated central-station units] [unhoused [return-air] [supply-air] service].
ON GRADE ON GRADE ON GRADE
BASEMENT 6096 MM 9144 MM 12192 MM
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
Through
14.9
kilowatt
250 to
300 rpm B-U-8.9 C-U-63 C-U-63 C-U-89
300 to
500 rpm B-U-8.9 C-U-44.5 C-U-44.5 C-U-63
500 rpm
and over B-U-8.9 C-U-25 C-U-25 C-U-44.5
Over 14.9
kilowatt
250 to
300 rpm B-U-8.9 C-U-63 C-CIB-89 C-CIB-89
300 to
500 rpm B-U-8.9 C-U-63 C-CIB-63 C-CIB-89
500 rpm
and over B-U-8.9 C-U-25 C-CIB-44.5 C-CIB-63
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN MILLIMETER
ON GRADE ON GRADE ON GRADE
BASEMENT 20-FOOT 30-FOOT 40-FOOT
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
Through
20 hp
200 to
300 rpm B-U-0.35 C-S-2.5 C-S-2.5 C-S-3.5
300 to
500 rpm B-U-0.35 C-S-1.75 C-S-1.75 C-S-2.5
500 rpm
and over B-U-0.35 C-S-1.0 C-S-1.5 C-S-1.75
Over 20 hp
250 to
300 rpm B-U-0.35 C-S-2.75 C-CIB-3.5 C-CIB-5.0
300 to
500 rpm B-U-0.35 C-S-1.75 C-CIB-2.5 C-CIB-3.5
500 rpm
and over B-U-0.35 C-S-1.0 C-CIB-1.75 C-CIB-2.5
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN INCHES
ON GRADE ON GRADE ON GRADE
BASEMENT 6096 MM 9144 MM 12192 MM
TYPE BELOW-GRADE FLOOR-SPAN FLOOR-SPAN FLOOR-SPAN
EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS* PROVISIONS*
Through
14.9
kilowatt
200 to
300 rpm B-U-8.9 C-S-63 C-S-63 C-S-89
300 to
500 rpm B-U-8.9 C-S-44.5 C-S-44.5 C-S-63
500 rpm
and over B-U-8.9 C-S-250 C-S-38 C-S-44.5
Over 14.9
kilowatt
250 to
300 rpm B-U-8.9 C-S-69.9 C-CIB-89 C-CIB-127
300 to
500 rpm B-U-8.9 C-S-44.5 C-CIB-63 C-CIB-89
500 rpm
and over B-U-8.9 C-S-25 C-CIB-44.5 C-CIB-63
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN MILLIMETER
2.2.12 Cross-Flow Cooling Tower Locations
NOTE: For blank spaces see notes at beginning of paragraph entitled, "Vibration-Isolation
Systems Application. Design vibration isolators capable of supporting towers
exposed to wind loading of 30 pounds per square foot 1437 pascal.
6096 MM 9144 MM 12192 MM
ROOF-SPAN ROOF-SPAN ROOF-SPAN
TYPE EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS*
Package under
tower base
to 500 rpm B-U-8.9 D-U-50 D-U-63
500 rpm and over B-U-8.9 D-U-25 D-U-44.5
Field erected
under tower
base; all rpm
Under mechanical-
equipment
supporting
frame to 500 rpm
500 rpm and over
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN MILLIMETER
20-FOOT 30-FOOT 40-FOOT
ROOF-SPAN ROOF-SPAN ROOF-SPAN
TYPE EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS*
Package under
tower base
to 500 rpm B-U-0.35 D-U-2.0 D-U-2.5
500 rpm and over B-U-0.35 D-U-1.0 D-U-1.75
Field erected
under tower
base; all rpm
Under mechanical-
equipment
supporting
frame to 500 rpm
500 rpm and over
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN INCHES
2.2.13 Blow-Through Cooling Tower Locations
6096 MM 9144 MM 12192 MM
ROOF-SPAN ROOF-SPAN ROOF-SPAN
TYPE EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS*
Under tower base
to 500 rpm B-U-8.9 C-S-63 C-S-89
500 rpm and over B-U-8.9 C-S-25 C-S-44.5
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN MILLIMETER
20-FOOT 30-FOOT 40-FOOT
ROOF-SPAN ROOF-SPAN ROOF-SPAN
TYPE EQUIPMENT PROVISIONS* PROVISIONS* PROVISIONS*
Under tower base
to 500 rpm B-U-0.35 C-S-2.5 C-S-3.5
500 rpm and over B-U-0.35 C-S-1.0 C-S-1.75
*TYPE OF MOUNTING, BASE, AND MINIMUM DEFLECTION IN INCHES
2.3 PIPE AND DUCT VIBRATION ISOLATION
NOTE: Drawings should show pipe and duct isolation required by project conditions.
Hanger-rod length should be long enough to dissipate conducted heat which might
be detrimental to elastomers.
Drawings should show type and spacing of pipe isolators in accordance with the
following guide:
Pipe Size (DN) Distance To Maximum Spacing
Millimeter Be Isolated Between Isolators
Inclusive Millimeter Millimeter
25 3048 3048
50 4572 3048
75 6096 3048
100 7620 3048
150 9144 3048
200 12192 3048
250 13716 3048
300 15240 3048
406 18288 3048
Pipe Size Distance To Maximum Spacing
Inches Be Isolated Between Isolators
Inclusive Feet Feet
1 10 10
2 15 10
3 20 10
4 25 10
6 30 10
8 40 10
10 45 10
12 50 10
16 60 10
Coordinate duct and piping drawings and specifications with respect to connected
vibration-isolated equipment deflections, expansion joints, and other flexible
equipment connections.
In addition to springs and rubber, high-density fibrous-glass segment pipe saddles
may be used for vibration isolation.
Type G: Isolators must be devices with in-series contained steel springs and preformed fibrous-glass or chloroprene-elastomer
elements for connecting to building-structure attachments. Load devices by supported system during operating
conditions to produce a minimum spring and elastomer static deflection of 25 millimeter and 10 millimeter 1 inch
and 3/8 inch, respectively.
NOTE: Use Type H and Type J isolators where necessary to support pipe beyond
tabulated distance.
Type H: Isolators must be devices with contained chloroprene-elastomer elements for connecting to building-structure
attachments. Load devices by supported system during operating conditions to produce a minimum elastomer static
deflection of 10 millimeter 3/8 inch.
Type J: Isolators must be devices with elastomers mounted on floor-supported columns or directly on the floor.
Load devices by supported system during operating conditions to produce a minimum elastomer static deflection
of 10 millimeter 3/8 inch.
2.3.1 Floor-Mounted Piping
Type K: Isolators must be devices with springs mounted on floor-supported columns or directly on the floor.
Load devices by supported system during operating conditions to produce a minimum spring static deflection of
25 millimeter 1 inch.
2.3.2 Vertical Piping
NOTE: For pipe approximately DN100 4 inches and larger.
Do not use Type l typical vertical pipe attachments on vibration-isolated pipe.
Type L: Isolators must be pipe base-support devices with one or more contained steel springs. Load devices
by supported system during operating conditions to produce a minimum static deflection of 25 millimeter 1 inch
. Equip devices with precompression and vertical-limit features, as well as a minimum 6.4 millimeter 1/4-inch
thick elastomer sound pad and isolation washers, for mounting to floor.
Type M: Isolators must be elastomer mounted baseplate and riser pipe-guide devices. Elastomer elements must
be contained double acting, and elastomers under rated load must have a minimum static deflection of 10 millimeter
3/8 inch. Size isolator to accommodate thermal insulation within the stationary guide ring.
PART 3 EXECUTION
3.1 INSTALLATION
Install equipment in accordance with manufacturer's recommendations.
[Rails, structural steel bases, and concrete inertia blocks must be raised not less than 25 millimeter 1 inch
above the floor and be level when equipment supported is under operating load.]
[Vibration-isolation installation and deflection testing after equipment start-up must be directed by a competent
representative of the manufacturer.]
3.2 TESTS AND REPORTS
[Vibration-isolation devices must be deflection tested. Submit test reports in accordance with paragraph entitled,
"Submittal Procedures," substantiating that all equipment has been isolated as specified and that minimum specified
deflections have been met. Make all measurements in the presence of the Contracting Officer.]