Hierarchy of Controls
This is the least desirable and least effective type of control on the 'Hierarchy of Controls'
What is PPE?
This is the permissible exposure limit set by OSHA for noise exposure over an 8-hour work shift, expressed in dBA.
What is 90 dBA TWA?
20 microPascals sometimes expressed as 2*10^-5 Pa.
What is the threshold of hearing?
This model is a common representation for sound propagation studies.
What is the source-path-receiver model?
This is the percentage of workplace noise-induced hearing loss that is preventable.
What is 100%?
These types of controls (which are all about making changes to processes, machinery or equipment so that the workers are exposed to less noise) are required by OSHA when feasible.
What are Engineering Controls?
This is the recommended exposure limit set by NIOSH for noise exposure over an 8-hour work shift, expressed in dBA.
What is 85 dBA?
This is applied to sound levels in an effort to account for the relative loudness perceived by the human ear, as the ear is less sensitive to low audio frequencies.
What is A-weighting?
This location is where the preferred method for noise control is usually applied.
What is at the source?
This can show the effectiveness of hearing protectors for each individual worker by determining their personal attenuation rating (PAR)
What is Fit-Testing?
When feasible, this is always the best control to use according to the 'Hierarchy of Controls.'
What is Elimination?
Employers must provide these baseline assessments within 6 months of an employee's first exposure at or above an 8-hour TWA of 85 dB.
What is an audiogram (or hearing test)?
This term describes all sound frequencies below 20 Hz. Humans do not really hear these frequencies.
What is infrasound?
Screens, barriers, partitions, and enclosures are all examples of this kind of noise control. They are used to reduce transmission of airborne sound between spaces.
What is sound insulation?
This instrument is used to check the performance of a sound level meter to a known sound source.
What is a calibrator?
This is a measure of the effectiveness of a hearing protection device to reduce noise levels.
What is Noise Reduction Rating (NRR)?
This is the average noise level over an 8-hour work shift for which OSHA requires a Hearing Conservation Program, expressed in dBA.
What is 85 dBA?
This process converts sound energy to heat.
What is sound absorption?
This electronically noise reduction technique usually uses 'anti-noise.'
What is active noise control?
This award recognizes innovation and organizations that document measurable achievements in hearing loss prevention.
What is the Safe-In-Sound Award?
According to NIOSH, increasing noise exposure by this number of decibels will generally 'halve' the time workers can spend at that noise level.
What is 3 decibels?
This is the minimum amount of time OSHA requires employers to keep noise exposure measurement records.
What is 2 years?
These are the upper and lower cut-off frequencies for an octave band centered at 1000 Hz.
What are 707.1 and 1414.2 Hz?
This engineering control can reduce noise produced by turbulence in pipes and ducts.
What is eliminating restricted flow?
Moving workers away from noisy process won't decrease their noise exposure in this type of field.
What is a reverberant field?