Master Plumber Exam Jobsite Safety and Regulations 4 — Questions and Answers
Question 1: What OSHA standard specifically governs excavation and trenching safety for plumbing contractors?
- 29 CFR 1910.147
- 29 CFR 1926.650-652 (Correct answer)
- 29 CFR 1926.502
- 29 CFR 1910.1200
Correct answer: 29 CFR 1926.650-652
OSHA 29 CFR 1926 Subpart P (sections 650-652) specifically covers excavations and trenching safety requirements in construction.
Question 2: A master plumber notices a 'competent person' has not inspected a trench after a rainstorm. What should happen BEFORE workers re-enter?
- Workers may re-enter after the water is pumped out
- A competent person must re-inspect and approve re-entry (Correct answer)
- The crew foreman may approve re-entry verbally
- Re-entry is allowed if no visible changes occurred
Correct answer: A competent person must re-inspect and approve re-entry
OSHA requires a competent person to inspect excavations after rain or other hazard-increasing events before workers are permitted to re-enter.
Question 3: Which personal protective equipment is required when operating a pipe threading machine?
- Safety glasses and cut-resistant gloves (Correct answer)
- Face shield and hearing protection only
- Respirator and steel-toed boots
- Safety glasses and a hard hat only
Correct answer: Safety glasses and cut-resistant gloves
Safety glasses protect against metal chips and cutting fluid splatter, while cut-resistant gloves protect hands from sharp pipe threads and the cutting die during pipe threading.
Question 4: Under the National Electrical Code (NEC) and plumbing safety practice, a plumber bonding a gas line must ensure the bonding jumper is sized to handle what?
- The maximum gas flow rate
- The fault current that could flow through it (Correct answer)
- The line pressure in PSI
- The pipe diameter in inches
Correct answer: The fault current that could flow through it
Bonding jumpers on gas piping must be sized to carry the maximum fault current that could flow in the event of an electrical fault contacting the pipe.
Question 5: A plumber is cutting cast iron pipe with a grinder. What respiratory protection is required for crystalline silica dust exposure?
- No protection needed for metal dust
- N95 filtering facepiece respirator (Correct answer)
- Half-mask with P100 cartridges
- Full-face SCBA
Correct answer: N95 filtering facepiece respirator
OSHA's silica standard (29 CFR 1926.1153) requires at minimum an N95 respirator when cutting materials that generate respirable crystalline silica dust.
Question 6: Under OSHA's heat illness prevention guidance, at what heat index level is a jobsite considered to be in the 'High' risk category?
- 91–103°F (Correct answer)
- 103–115°F
- 80–90°F
- Above 115°F
Correct answer: 91–103°F
OSHA classifies a heat index of 91–103°F as 'High' risk, requiring additional precautions such as frequent rest breaks, shade, and hydration.
Question 7: A plumber is required to have a confined space permit. Which item does NOT need to be on the permit?
- Atmospheric test results
- Names of authorized entrants
- The cost estimate for the job (Correct answer)
- Duration of the permit
Correct answer: The cost estimate for the job
OSHA's permit-required confined space standard (29 CFR 1910.146) specifies required permit elements including atmospheric tests, authorized entrants, and duration — but not job cost.
Master Plumber Exam Jobsite Safety and Regulations 4
What OSHA standard specifically governs excavation and trenching safety for plumbing contractors?