Lather / Interior Systems Mechanic (451A) — Red Seal

Performs common occupational skills

How far above an upper landing must a straight ladder extend when it is used to access an elevated work platform?

1. At least one metre, about three rungs, above the landing or upper support point
2. Level with the landing surface, so the ladder does not obstruct the platform edge
3. Exactly half a metre above the landing in every situation, regardless of platform
4. As far as the ladder happens to reach, since there is no minimum extension rule

A straight ladder used for access must extend at least one metre, about three rungs, above the landing so the worker has a secure handhold while stepping on and off. Stopping level with the landing leaves nothing to grip during the transition, which is when most ladder falls happen. A fixed half-metre is below the required handhold height, so it does not give a safe grip. Leaving it to whatever the ladder reaches ignores the minimum-extension rule that controls the detail. Extending at least one metre above the landing is the correct access setup.

RSOS 2021 | A-2.07 Uses scaffolding and access equipment

Performs framing activities

A long bulkhead frame twists out of plane after the soffit board is hung. What most likely went wrong during framing?

1. The bulkhead lacked adequate bracing back to the structure before it was clad
2. Too many screws were used to fasten the board onto the soffit of the bulkhead
3. The board was hung in the wrong colour for the design that was specified there
4. The room humidity was too low while the soffit board was being installed there

A bulkhead that twists out of plane after cladding usually lacked adequate bracing back to the structure, which left the frame free to rack under the added weight of the board. Using extra screws to fasten the board does not cause the frame to twist out of plane. Board colour is a finish matter and has no effect on whether the frame stays straight. Low humidity does not twist a steel frame. Missing bracing back to the structure is the most likely cause of the twist.

RSOS 2021 | B-6.04 Frames non-loadbearing bulkheads

Installs interior systems

An access panel must be installed in a one-hour fire-rated shaft wall to reach a valve. What type of panel is required?

1. Any plain hinged steel door panel, since all it has to do is cover over the opening in the wall
2. An open framed hole left with a loose board dropped in front of it for quick easy hand access
3. A fire-rated access panel that matches the required rating of the wall assembly
4. A light plastic panel picked mainly because its smooth face is the easiest one to wipe down clean

A penetration in a fire-rated wall must be closed with a fire-rated access panel that matches the wall's required rating, or the fire separation is broken at that point. A standard non-rated metal panel defeats the rated separation even though it covers the opening. An open hole with a loose board provides no rated closure at all. A plastic panel offers no fire resistance and would fail in a fire. A fire-rated access panel matching the wall rating is what is required.

RSOS 2021 | C-8.06 Installs access panels