TABLE 3A
Vibration Isolator Types and Minimum Static Deflection
(MSD, mm) for 100-200 mm slab on grade and column supported.
Column
Slab on earth
9.1-12 meters
12.1-15 meters
Spacing
and 0-9 meter
Equipment
Type
MSD
Type
MSD
Type
MSD
_________
(Note (1))
(Note (1))
(Note (1))
I
- Concrete inertia bases with steel forms.
NM - Neoprene mounts.
NP - Neoprene pads.
R
- Structural steel rail for equipment mounts.
S
- Freestanding spring isolators (floor-mounted equipment).
SV - Freestanding spring isolators (floor-mounted equipment).
SX - Freestanding spring isolators with adjustable
cushioned vertical stops and cushioned horizontal stops
(floor-mounted equipment). Protected spring isolators
SX may be substituted wherever S or SV is specified and
shall meet all requirements.
(2)
Fans
a.
When fan motors are 56 kW or larger, use the
deflection requirements for the next wider column
spacing. Except for building slab on grade a minimum of
63.50 mm should be used unless larger deflections
are specified in the centrifugal blower table.
b.
Provide sway brace isolators for tubular centrifugal and
axial fans when the fan pressure exceeds 996 Pa.
c.
Provide inertia bases for all fans in lieu of structural
steel bases or rails specified above when the fan
pressure exceeds 996 Pa.
d.
With attaching brackets, suspension spring isolators
bridge between the structure and the thrust-producing
machinery such as high-pressure fan. Both types H and
HR normally provide reaction in tension, while types S,
SV, and SX normally provide reaction in compression.
Thrust restraints are low-cost and effective components
available from manufacturers. Use thrust restraints to
eliminate the need for or reduce the magnitude of inertia
mass when the mass is only used to reduce the
displacement effects of the thrust.
SECTION 15070N
Page 44
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