Model SG-100 Plasma Spray Gun
Operator’s
Manual
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Issued: 10/11
Page
13
contains many variables, so each case must be treated individually. This
manual can provide only general suggestions for noise control.
Use engineering or administrative controls to reduce noise or noise
exposure. Engineering controls include: redesign equipment, relocate
equipment, change operating conditions, isolate equipment acoustically,
insulate work area, and provide operator hearing protection.
Administrative controls include planning and scheduling to reduce
exposure.
If engineering and administrative controls do not achieve acceptable noise
control,
OSHA
regulations allow use of suitable personal protective
equipment. This also applies while engineering and administrative
controls are being established.
Mufflers on thermal spray equipment are impractical and ineffective.
Simple baffles between the gun and nearby personnel are not effective
because noise scatters around the baffle. Specially designed sound
absorbing materials provide a 5 dB reduction to adjacent areas. Sound
absorbing materials on walls and hanging baffles can reduce nearby levels
but do not solve the problem for the operator.
Relocate Equipment
Increasing the distance between the noise source and the receiver lowers
the sound pressure level. Table 1-4 lists how increasing distance can
reduce decibels in a free field.
Table 1-4
Using Distance to Reduce Decibels
Distance from
Source
Theoretical dBA
Reduction
3 feet (1 m)
0
10 feet (3 m)
10
30 feet (9 m)
20
90 feet (27 m)
28
Isolate Equipment
Isolate noise by moving it away from affected personnel or placing the
equipment in an acoustically insulated enclosure. Praxair Surface
Technologies offers spray rooms that enclose spray operations and confine
noise. These rooms are designed to limit the noise level to specified limits