Vibration Restrained Curb-mounted Spring Rail: Model KSCR 2.0 – All rooftop air-handling units shall be supported by vibration isolation
curbs as manufactured by Kinetics Noise Control. The vibration isolation curbs shall be complete assemblies designed to resiliently
support the equipment at the specified elevation and shall constitute a fully enclosed air- and weather-tight system.
The isolation curb shall consist of an upper support rail with supply and return flexible connector supports on which the equipment
and duct openings rest and a lower support curb which is attached to the roof structure, separated by free-standing, unhoused,
laterally stable steel springs and lateral seismic and/or wind load restraints.
The upper support rail shall provide continuous structural support for the rooftop equipment and shall be designed to provide
isolation against casing-radiated vibration in the rooftop equipment housing and structure-borne vibration from rotating and
mechanical equipment in the rooftop package.
The lower support curb shall be a formed channel fabricated of heavy gauge galvanized steel with a continuous 1-1/2" x 1-1/2"
(38 mm x 38 mm) nominal wood nailer. The base plate of the curb shall be 1" (25 mm) wide and shall be welded, bolted or screwed
to the building support steel.
The lower support curb shall have a minimum elevation of 14" (356 mm). Spring components shall be 1" (25 mm) 2" (51 mm) deflection,
freestanding, unhoused, laterally stable steel springs. Springs shall have a lateral stiffness greater than 1.0 times the rated
vertical stiffness and shall be designed for a typical 50% overload to solid. All springs shall have a polyester powder coated
finish and be color coded to indicate load capacity.
Upper support rail and lower support curb are connected by spring isolators and a continuous air- and water-tight seal strip. This seal strip
shall be a fabric reinforced polymeric material retained in both the upper support rail and lower support curb. The seal strip shall be sealed
along the top and bottom with aluminum clamp strips. Corner seals shall be elastomeric material retained to both the top and bottom rails. Rail
assemblies shall incorporate means for attachment to the building and the supported equipment and shall incorporate additional stiffening members
if necessary to assure stability. The seal strips shall provide wind restraints suitable for prevailing wind conditions that will not impose
loads on the curb walls at 90 degrees to their long axis.
Supply and return flexible connector support hardware shall be supplied for installation by the contractor in the field. The supports will
be clearly marked and dimensioned on the submittal and installation drawings. The support hardware shall be cut-to-length, galvanized steel
channels supported and connected with stamped and punched galvanized steel duct support hangers.
The support hangers shall allow the duct support elevation to be equal to or lower than the equipment rail elevation. Supply and return air
duct shall be flexibly attached by the contractor to prevent transmission of vibration to the building structure.
The isolation curb assemblies shall be shipped to the job site with the upper support rail, lower support curb, springs, and seal strip. The
contractor shall assemble the four corners and attach the curb to the roof structure.
The isolation curb assembly shall include a trouble shooting kit to permit the contractor to level or adjust the loading of the isolation
system immediately after placement of the rooftop equipment should the actual weight and/or distribution differ from design values.
Vibration isolators shall be selected by the manufacturer for each specific application to comply with deflection requirements as shown on
the Vibration Isolation Schedule or as indicated on the project documents.
Roof curb shall be Model KSCR 2.0 as manufactured by Kinetics Noise Control.