Advanced Application of Safety Principles practice questions

Answer: A) It lowers the incident energy reaching the worker by increasing the distance from a potential arc

Remote racking is a distance-based control. Incident energy decreases as the working distance increases, so operating from outside the arc flash boundary greatly reduces the worker's exposure if an arc occurs during racking.

• ACorrect. OSHA identifies racking a circuit breaker as a task that exposes employees to arc hazards. Arc flash incident energy depends mainly on current, arc duration and worker distance. Moving the worker farther away lowers the energy that reaches them, though the rate of decrease depends on the equipment and whether the arc is enclosed. Working remotely can put the worker outside the arc flash boundary.
• BIncorrect. The system's available fault current depends on the source impedance and the system design. Where the operator stands has no effect on it.
• CIncorrect. Remote racking only reduces exposure during the racking operation itself. Work on the breaker still requires de-energizing, lockout/tagout and verifying that no voltage is present.
• DIncorrect. Clearing time is set by the protective device and its relay or trip settings. Examples are maintenance switches and arc-flash relays. It does not depend on where the operator stands.

Answer: B) The technician plus all tools, equipment and materials carried onto the ladder

OSHA 1910.23 requires that ladders not be loaded beyond their maximum intended load. That load is the combined weight and force of the worker and everything they carry onto the ladder.

• AIncorrect. The design safety factor is not extra room for carried items. The maximum intended load already includes tools and materials.
• BCorrect. OSHA defines maximum intended load as the total load (weight and force) of the employee and all tools, equipment and materials carried. The ladder's rating must cover that total.
• CIncorrect. The rating does not assume a standard worker weight. The employee's actual weight is part of the total load.
• DIncorrect. Capacity is based on the combined load on the ladder, not on one item. Leaving out the worker's weight makes overloading likely.

Answer: B) 10,000 pounds in a process

• AIncorrect. That's far too low.
• BCorrect. Smaller amounts may fall under other rules.
• CIncorrect. That's far too high.
• DIncorrect. It's covered above the threshold.

Answer: A) 1/8 inch

• ACorrect. A wider gap can trap work and break the wheel.
• BIncorrect. The limit is 1/8 inch.
• CIncorrect. The limit is 1/8 inch.
• DIncorrect. The limit is 1/8 inch.

Answer: A) Water is nearly incompressible, so the pressurized system holds far less stored energy to release if it ruptures

Pneumatic tests are more dangerous because compressed gas stores much more potential energy than nearly incompressible water. A failure during a hydrostatic test therefore releases far less energy.

• ACorrect. A gas compresses and stores a large amount of potential energy, so a rupture can be violent and throw fragments. Water barely compresses, so a failure during a hydrostatic test releases much less energy.
• BIncorrect. The test pressure is set by the test requirements, not by the fluid's density. Density does not lower the pressure needed, and it is not why hydrostatic testing is safer.
• CIncorrect. A static fluid, liquid or gas, transmits pressure equally in all directions (Pascal's principle). The safety benefit comes from the lower stored energy, not from uneven pressure.
• DIncorrect. Visible leaks help with inspection, but they don't remove the need to control the area. Any pressure test still needs safeguards to protect people in case of failure.

Answer: B) Scheduled testing of cords and tools

• AIncorrect. Grounding is required.
• BCorrect. Records are kept.
• CIncorrect. Tests are scheduled.
• DIncorrect. New tools still need inspection.

Answer: A) An actual or potential hazardous atmosphere that continuous forced-air ventilation alone keeps safe for entry

Alternate procedures under 1910.146(c)(5) are allowed only when the sole hazard is an actual or potential hazardous atmosphere that continuous forced-air ventilation alone keeps safe for entry, and monitoring and inspection data support this.

• ACorrect. Paragraph (c)(5)(i)(A)-(B) requires that the only hazard be an actual or potential hazardous atmosphere and that continuous forced-air ventilation alone be enough to keep the space safe for entry. The employer must also have monitoring and inspection data to support this.
• BIncorrect. Alternate procedures are limited to atmospheric hazards. An engulfment hazard requires full permit-space procedures.
• CIncorrect. The condition is that continuous forced-air ventilation alone keeps the space safe. Needing respirators to control the atmosphere does not meet that condition.
• DIncorrect. A mechanical hazard is not atmospheric, so alternate procedures do not apply. (Removing all hazards without ventilation is a different case, covered by reclassification under (c)(7).)

Answer: A) Shut down the burner when the water level falls to the lowest safe level

A low-water fuel cutoff stops the burner when water drops to the lowest safe level. This keeps the heating surfaces from overheating, which can cause boiler failure or explosion.

• ACorrect. If the burner keeps firing after the water level has dropped, the heating surfaces lose their water cooling. They can overheat, warp, or fail. The cutoff stops firing before that happens, and regulations require that this shutdown be tested.
• BIncorrect. Even at low fire, heat keeps going into surfaces that may already be uncovered. Feeding water onto overheated metal can also cause sudden steam generation. The protective action is to stop firing, not to keep firing at a reduced rate.
• CIncorrect. A safety valve responds to pressure, not water level. Venting steam does not restore water. It actually removes more water from the boiler.
• DIncorrect. Operators use blowdown during maintenance and testing. An automatic blowdown during a low-water condition would drain even more water and make the hazard worse.

Answer: A) The truck's capacity data plate (nameplate)

A powered industrial truck's rated capacity at a given load center is shown on its manufacturer data plate. The plate must be updated when attachments or approved modifications change the truck's capacity.

• ACorrect. The manufacturer's data plate lists rated capacity at specified load centers and lift heights. OSHA 1910.178 requires that capacity-affecting modifications get the manufacturer's written approval. It also requires the truck to be marked for non-factory attachments, so the plate must match the truck's current setup.
• BIncorrect. Rack signs show what the shelving can hold, not what the truck can safely lift. Truck capacity is on the truck's data plate.
• CIncorrect. The pre-shift checklist records the condition of brakes, horn, hydraulics and so on. It is not where the manufacturer's rated capacity is given. That information is on the data plate.
• DIncorrect. Shipping papers can give the load's weight, but not the truck's rated capacity at a given load center. That must be checked on the data plate.

Answer: A) One authorized employee has primary responsibility, and each worker attaches a personal lock to the group lockbox

Group lockout applies when a crew services the same equipment. One authorized employee has primary responsibility, and every worker attaches a personal lock or tag to the group lockbox, which gives protection equivalent to individual lockout (29 CFR 1910.147(f)(3)).

• ACorrect. Under 1910.147(f)(3)(ii)(A) and (D), primary responsibility goes to one authorized employee. Each authorized employee attaches a personal lockout or tagout device to the group lockout device, group lockbox, or similar mechanism when starting work, and removes it when finished.
• BIncorrect. The workers would have no personal control over the locks. 1910.147(f)(3)(i) requires protection equivalent to each worker's own personal lockout or tagout device.
• CIncorrect. Operator controls are not energy-isolating devices. Tags placed there do not give each worker protection at the isolation points, and each worker's device must go on the group lockout device or lockbox.
• DIncorrect. Checking someone else's lock gives no personal protection. If that worker removes the locks, the rest of the crew is exposed. Each authorized employee must attach their own device.