TABLE 3B
Class II Vibration Isolator Types and Minimum Static Deflection
(MSD, inches) for basements below grade and floor slabs on earth
Equipment
Type (Note (1))
MSD
225 - 299 rpm
NM-B
0.35
300 - 374 rpm
NM-B
0.35
375 - 499 rpm
NM-B
0.35
Over 500 rpm
NM-B
0.35
Tubular Centrifugal
and Axial Fans
(Note (2))
Suspended
H with deflections specified for
centrifugal blowers
Floor Mounted
Arrangements 1 & 9
NM
0.35
Utility Fans
(Note (2))
Suspended and
H with deflections specified for
centrifugal
Floor Mounted
NM
0.35
High-Pressure Fans
HR recommended for minimizing
(Over 6 Inch
undesirable thrust effects
Water-Column
Static Pressure)
and Other
Machines
Producing Thrust
(Note (2))
Internal Combustion
Engines and Engine
Driven Equip
750 rpm and over
S
1.0
Dimmer Banks and
Up to 1000 lbs.
NP
0.25
NM
0.35
Over 1000 lbs.
SV
1.0
NOTES:
Note (1) and Note (2) are same as for TABLE 3A.
On the roof or upper floors, mount machinery on isolators with vertical
stops. Rest isolators on beams or structures designed and installed in
accordance with the SMACNA Arch. Manual, Plate 61.
SECTION 15070N
Page 53
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