CHST - Construction Health and Safety Technician Health Hazards and PPE Questions and Answers 1 — Questions and Answers
Question 1: A construction worker is tasked with dry cutting concrete block with a handheld power saw for a full 8-hour shift. According to OSHA's silica standard for construction (29 CFR 1926.1153), which of the following represents the most effective and compliant method for controlling the respirable crystalline silica hazard?
- Providing the worker with a half-mask respirator with an APF of 10.
- Using a saw equipped with an integrated water delivery system. (Correct answer)
- Restricting access to the work area and using a fan for ventilation.
- Implementing job rotation to limit each worker's cutting time to two hours.
Correct answer: Using a saw equipped with an integrated water delivery system.
The most effective control measure listed is using a saw with an integrated water delivery system. This is an engineering control that prevents the silica dust from becoming airborne at the source. While respirators are a form of PPE, the hierarchy of controls prioritizes engineering controls over PPE. Administrative controls like restricting access or job rotation are also less effective than engineering controls.
Question 2: A safety technician calculates the required attenuation for hearing protection in an area with an A-weighted Time-Weighted Average (TWA) noise exposure of 102 dBA. The company policy is to use OSHA's standard formula for estimating workplace protection. If a worker uses earplugs with a Noise Reduction Rating (NRR) of 33, what is the estimated exposure in dBA under the protector?
- 69 dBA
- 76 dBA (Correct answer)
- 84 dBA
- 70 dBA
Correct answer: 76 dBA
OSHA's formula for estimating the protected A-weighted TWA from an A-weighted measurement is to subtract 7 from the NRR, and then subtract the result from the measured TWA. Calculation: NRR 33 - 7 = 26. Then, 102 dBA - 26 = 76 dBA. This estimated exposure is below the OSHA Permissible Exposure Limit (PEL) of 90 dBA and the action level of 85 dBA.
Question 3: According to OSHA regulations for personal fall arrest systems (PFAS) in construction, when must the equipment be inspected?
- Annually by a qualified person.
- Before each use by the user and annually by a competent person. (Correct answer)
- Only after a fall event has occurred.
- At the beginning of each new project by the site supervisor.
Correct answer: Before each use by the user and annually by a competent person.
OSHA 1926.502(d)(21) requires that personal fall arrest systems be inspected prior to each use for wear, damage, and other deterioration. In addition to this user inspection, the equipment must be inspected at least annually by a competent person.
Question 4: A worker is assigned to a task where the airborne concentration of a hazardous substance is 400 µg/m³. The Permissible Exposure Limit (PEL) for this substance is 50 µg/m³. The worker is provided with a half-mask air-purifying respirator. What is the minimum Assigned Protection Factor (APF) required, and does the provided respirator meet this requirement?
- APF 5; Yes, the respirator is adequate.
- APF 10; No, a higher level of protection is needed.
- APF 8; Yes, the respirator is adequate.
- APF 10; Yes, the respirator is adequate. (Correct answer)
Correct answer: APF 10; Yes, the respirator is adequate.
The required APF is calculated by dividing the measured concentration by the PEL: 400 µg/m³ / 50 µg/m³ = 8. Therefore, a respirator with an APF of at least 8 is required. According to OSHA, a half-mask air-purifying respirator has an APF of 10. Since 10 is greater than the required 8, the respirator is adequate for the task.
Question 5: During lead abatement activities involving manual scraping of lead-based paint, which of the following housekeeping practices is explicitly prohibited by OSHA's Lead in Construction standard (29 CFR 1926.62)?
- Using a HEPA-filtered vacuum for cleanup.
- Wet-sanding the painted surfaces.
- Using compressed air to remove lead dust from surfaces. (Correct answer)
- Placing contaminated clothing in sealed containers.
Correct answer: Using compressed air to remove lead dust from surfaces.
OSHA standard 29 CFR 1926.62(h)(5) prohibits the use of compressed air to remove lead from any surface unless it is used with a ventilation system designed to capture the dust. This practice is banned because it disperses hazardous lead dust into the air, increasing the risk of inhalation. HEPA vacuuming, wet methods, and proper disposal of contaminated clothing are all required or recommended practices.
Question 6: Which of the following is considered the LEAST effective method for controlling workplace hazards according to the hierarchy of controls?
- Substitution
- Engineering controls
- Personal Protective Equipment (PPE) (Correct answer)
- Administrative controls
Correct answer: Personal Protective Equipment (PPE)
The hierarchy of controls ranks hazard control methods from most to least effective. The order is: Elimination, Substitution, Engineering Controls, Administrative Controls, and finally, Personal Protective Equipment (PPE). PPE is considered the last line of defense because it relies on the worker to wear and use it correctly and does not remove the hazard from the environment.
CHST - Construction Health and Safety Technician Health Hazards and PPE Questions and Answers 1
A construction worker is tasked with dry cutting concrete block with a handheld power saw for a full 8-hour shift.
According to OSHA's silica standard for construction (29 CFR 1926.1153), which of the following represents the most effective and compliant method for controlling the respirable crystalline silica hazard?