ABA Safety Systems & Standards 2 — Questions and Answers
Question 1: Which OSHA permissible exposure limit (PEL) for noise uses a 5 dB exchange rate over an 8-hour TWA?
- 85 dBA
- 90 dBA (Correct answer)
- 95 dBA
- 80 dBA
Correct answer: 90 dBA
OSHA's PEL is 90 dBA TWA with a 5 dB exchange rate, meaning each 5 dB increase halves the allowable exposure time.
Question 2: Under OSHA's Hearing Conservation Amendment, audiometric testing must be provided to workers exposed at or above what action level?
- 90 dBA TWA
- 85 dBA TWA (Correct answer)
- 80 dBA TWA
- 95 dBA TWA
Correct answer: 85 dBA TWA
OSHA's action level is 85 dBA TWA, triggering requirements for audiometric testing, training, and hearing protection.
Question 3: What is the maximum sound pressure level allowed for audiometric test booth ambient noise in the low-frequency octave band centered at 500 Hz per ANSI S3.1?
- 40 dB SPL
- 29 dB SPL (Correct answer)
- 21 dB SPL
- 35 dB SPL
Correct answer: 29 dB SPL
ANSI S3.1 specifies that ambient noise in test booths at 500 Hz must not exceed 29 dB SPL to avoid masking during threshold testing.
Question 4: Which standard governs the acoustic performance requirements for audiometric test enclosures in the United States?
- ANSI S3.6
- ANSI S3.1 (Correct answer)
- ISO 8253-1
- OSHA 1910.95
Correct answer: ANSI S3.1
ANSI S3.1 specifies maximum permissible ambient noise levels inside audiometric test rooms to ensure valid threshold measurements.
Question 5: A worker's noise dose reading is 50% at the end of a shift. According to OSHA, this is:
- Above the PEL and requires immediate hearing protection
- Below the PEL but above the action level if TWA ≥ 85 dBA (Correct answer)
- At exactly the PEL
- Below the action level and requires no action
Correct answer: Below the PEL but above the action level if TWA ≥ 85 dBA
A 50% dose equals an 85 dBA TWA, which meets OSHA's action level threshold triggering hearing conservation program requirements.
Question 6: When fitting hearing protection devices, the Noise Reduction Rating (NRR) must be derated by what factor per OSHA guidance for earmuffs?
- 25%
- 50% (Correct answer)
- 75%
- No derating required
Correct answer: 50%
OSHA recommends derating earmuff NRR by 50% (using half the labeled NRR) to account for real-world fit variability.
Question 7: Which organization publishes the Recommended Exposure Limit (REL) of 85 dBA TWA with a 3 dB exchange rate for occupational noise?
- OSHA
- NIOSH (Correct answer)
- EPA
- ACGIH
Correct answer: NIOSH
NIOSH recommends an 85 dBA TWA REL with the more conservative 3 dB exchange rate, which is stricter than OSHA's standard.
ABA Safety Systems & Standards 2
Which OSHA permissible exposure limit (PEL) for noise uses a 5 dB exchange rate over an 8-hour TWA?