Flowserve MNV - Manual (Page 9)

MNV & MNZ USER INSTRUCTIONS ENGLISH 71569188 11/04
Page 9 of 47
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1.8 Noise level
Whenever pump noise level exceeds 85 dBA, attention must be given to prevailing Health and Safety
Legislation, to limit the exposure of plant operating personnel to the noise. Typical safety level requires to limit
the sound level of 90 dBA for 8 hours of exposure and the allowable dBA value increases 5 dBA for each
halving of exposure time. The usual approach is to control exposure time to the noise or to enclose the
machine to reduce emitted sound.
You may have already specified a limiting noise level when the equipment was ordered, however if no noise
requirements were defined then machines above a certain power level will exceed 85 dBA. In such situations,
consideration must be given to the fitting of an acoustic enclosure to meet local regulations.
1.8.1 Typical sound levels for MNV & MNZ pumps
Typical sound pressure levels measured in dB, and are A-weighted.
Motor
Frame
Size.
NEMA
RPM Motor Only
Sound
Pressure
(dBA )
Pump only
Sound
Pressure
(dBA )
Combination
of pump and
motor
Sound
pressure
(dBA)
1800 60.0 65 70 180
1200 & slower 55.0 55 63
1800 60.0 65 69 210
1200 & slower 55.0 56 63
1800 70.0 77 77 250
1200 & slower 60.0 68 69
1800 70.0 77 77 280
1200 & slower 60.0 68 69
1800 65.0 77 77 320
1200 & slower 65.0 69 69
1800 65.0 77 78 360
1200 & slower 65.0 68 69
1800 70.0 77 78 400
1200 & slower 65.0 68 69
1800 70.0 77 78 440
1200 & slower 65 68 69
Sound pressure values indicated for the motor are extracted from typical motor manufacturer’s data at no load
conditions and are not guaranteed. They may vary depending on the type of motor, enclosure used, and the
manufacturer. The sound pressure values for the pump are estimated levels in free field measured 1 meter from the
nearest major pump surface and at a height of 1.5 meters above the floor. using speed, flow rate, motor horsepower,
number of impeller vanes, and other variables. Therefore values indicated are for reference only and could exceed
the estimated values by as much as 8~10 dBA depending upon factors such as installed conditions, building
acoustics, foundation, piping, operating conditions, surrounding machinery. It is highly recommended to take actual
field measurement of sound pressure values, apply enclosures and safety measures mandated by the local
authorities and prevailing safety regulations. For all other pump and motor frame size combinations, the sound
levels have to measured and safety measures have to be adopted.
For units driven by equipment other than electric motors or units contained within enclosures, see the
accompanying information sheets and manuals.