Environmental Engineering Reference
In-Depth Information
Table 1.1 osha PerMissible exPosure
levels for WorKPlaCe noise
Maximum Time
of exposure (hr)
sound level (db)
85 (program required)
8
90 (hearing protection required)
8
92
6
95
4
97
3
100
2
102
1.5
105
1
110
0.5
115
0.25
an introduction stating the OSHA requirements. The program objec-
tives should be clearly stated. Designation of responsibilities should be
included, with a statement that the program requires good direction,
management, supervision, and conduct at all work levels within the
plant site. Include a section that defines key terms. One part of the writ-
ten hearing conservation program should identify the exact locations at
the plant site where the noise hazards exist. When these noise hazard
areas have been identified, the written program should require label-
ing or marking of these areas. OSHA's permissible noise exposures are
listed in Table 1.1.
When it has been determined what type of noise hazard warning will
be used and where each sign is to be posted, the next item that should
be included in the hearing conservation program is an evaluation of
engineering and administrative controls. Incorporating engineering and
administrative controls into your hearing conservation program should
be looked at closely.
In the world of safety, it is always best, if possible
and feasible, to try to engineer out a safety hazard instead of guarding
against it. Engineering out the noise problem might include such things
as installing mufflers on air-exhaust nozzles or isolating a machine. If
the noise source cannot be damped, then perhaps something can be
done about the noise path. Placing sound-absorbent enclosures around
noisy equipment is a modification that can be easily accomplished. As a
last engineering control measure, protecting the receiver of the noise is
another solution. This can be accomplished by constructing an enclo-
sure around the employee's workstation.
When engineering controls are not possible, feasible, or cost effec-
tive, then administrative controls are called for. The primary administra-
tive control used to protect workers from unwanted sound or noise is to
issue each worker hearing protection devices. Hearing protection devices
include earplugs and earmuffs. Earplugs offer the most protection, and
properly installed foam earplugs are the most effective. Earmuffs fit over
the outside of the ear. Many workers feel that earmuffs provide more
protection than earplugs, but this is usually not the case. Earmuffs are
