CAT Industry Knowledge and Safety Standards 2 — Questions and Answers
Question 1: Under OSHA regulations, what is the permissible exposure limit (PEL) for continuous noise over an 8-hour workday?
- 85 dB(A)
- 90 dB(A) (Correct answer)
- 95 dB(A)
- 100 dB(A)
Correct answer: 90 dB(A)
OSHA sets the 8-hour TWA PEL for noise at 90 dB(A), with a 5 dB exchange rate.
Question 2: Which NFPA code specifically governs the installation of audio/visual systems in life safety applications?
- NFPA 70
- NFPA 72 (Correct answer)
- NFPA 101
- NFPA 110
Correct answer: NFPA 72
NFPA 72, the National Fire Alarm and Signaling Code, covers audio/visual emergency notification systems.
Question 3: What does the acronym MSDS stand for in the context of commercial audio installation?
- Minimum Sound Distribution Standard
- Material Safety Data Sheet (Correct answer)
- Multi-Source Distribution System
- Maximum Signal Distortion Specification
Correct answer: Material Safety Data Sheet
MSDS (now called SDS under GHS) provides hazard information for chemicals used during installation such as adhesives and solvents.
Question 4: A CAT technician is working in a venue with a reverb time of 3.5 seconds. Which treatment would most effectively reduce low-frequency buildup?
- Broadband fiberglass panels
- Polycylindrical diffusers
- Corner-mounted bass traps (Correct answer)
- Ceiling cloud reflectors
Correct answer: Corner-mounted bass traps
Bass traps placed in room corners are most effective at absorbing low-frequency energy where it naturally accumulates.
Question 5: Which standard defines the minimum wire gauge requirements for speaker circuits carrying 70-volt distributed audio in commercial installations?
- NEC Article 640 (Correct answer)
- NEC Article 725
- NEC Article 800
- NEC Article 820
Correct answer: NEC Article 640
NEC Article 640 addresses audio signal processing and amplification equipment, including speaker wiring requirements.
Question 6: When installing a ceiling speaker in a plenum space, what cable type is required by the NEC?
- CL2 rated cable
- CMP rated plenum cable (Correct answer)
- CMR rated riser cable
- CM rated general-purpose cable
Correct answer: CMP rated plenum cable
CMP (Communications Multipurpose Plenum) rated cable is required in plenum spaces because it has low smoke and flame-spread characteristics.
Question 7: What is the standard impedance for a professional balanced audio line in commercial AV installations?
- 8 ohms
- 75 ohms
- 600 ohms (legacy) / low impedance bridging (Correct answer)
- 10,000 ohms
Correct answer: 600 ohms (legacy) / low impedance bridging
Professional audio uses low-impedance outputs (typically 50–200 ohms) driving high-impedance inputs (10k+ ohms) in a bridging configuration, evolved from the legacy 600-ohm standard.
CAT Industry Knowledge and Safety Standards 2
Under OSHA regulations, what is the permissible exposure limit (PEL) for continuous noise over an 8-hour workday?