CPM Safety & Compliance in Plant Operations 2

Question 1

Under OSHA 29 CFR 1910.147, which step must be done immediately after applying locks and tags and before starting work on a machine?

Accepted Answer

Verify isolation by attempting to operate the equipment

Answer

Verifying zero energy by trying to start the machine (then returning controls to off) confirms the isolation actually worked.

Question 2

Two mechanics are working on the same conveyor drive under lockout. What is the correct lockout practice?

Accepted Answer

Each mechanic applies a personal lock, often using a group lockout hasp

Answer

Every authorized employee working on the equipment must have their own lock on the isolation point or group lockbox.

Question 3

What OSHA eight-hour time-weighted average noise level triggers the requirement for a hearing conservation program?

Accepted Answer

85 dBA

Answer

The action level of 85 dBA TWA requires a hearing conservation program with audiometric testing and protectors available.

Question 4

Before entering a permit-required confined space, in what order should the atmosphere be tested?

Accepted Answer

Oxygen, flammables, toxic gases

Answer

Oxygen is tested first because many combustible gas sensors need adequate oxygen to read correctly, followed by flammables and then toxics.

Question 5

What is the acceptable oxygen concentration range for safe confined space entry under OSHA?

Accepted Answer

19.5% to 23.5%

Answer

Below 19.5% is oxygen-deficient and above 23.5% is oxygen-enriched, which raises fire risk.

CPM - Certified Plant Mechanic Practice Test