OSHA. Flashcards
- How is scaffolding sometimes called?
Staging.
- What is a scaffold?
Temporary elevated work platforms used to hold worker and materials.
- What are three basic types of scaffolds?
- Supported scaffolds.
- Suspension scaffolds.
- Aerial lifts.
- What are supported scaffolds?
Rest on posts, uprights, frames, or outrigger beams. Some are mounted on casters - or on trucks.
- What are suspension scaffolds?
Hang by ropes or other mon-rigid means from an overhead structure.
- What are aerial lifts?
Vehicle mounted elevating and rotating work platforms.
- How many kinds of scaffolds are there?
The OSHA scaffold standard covers 39 scaffolds.
- What are common scaffolds in residential construction?
- Fabricated frame scaffolds.
- Window jack scaffolds.
- Trestle ladder scaffolds.
4 ladder jack scaffolds. - Horse scaffolds.
- Aerial lifts.
- Four common type of supported scaffold?
- System scaffolds.
- Ladder jack scaffolds.
- Sawhorse scaffolds.
- Mobile scaffolds.
- What are types of suspension scaffolds?
- Two-pint suspension.
- Boatswain’s chairs.
- Interior hung scaffolds.
- Float or ship scaffolds.
- How are scaffolds constructe?
Most use traditional beam and post construction.
- What are vertical parts of the scaffolds?
Legs or uprights. Uprights may be called posts and standards.
The supporting ropes or cables on suspension scaffolds.
Ladders attached to the frame or build into the frame.
- What does upright include?
- Welded frames.
- Steel or aluminum tubes.
- Wood poles.
- What does horizontal parts of scaffold includes?
- Platforms.
- Runners.
- Putlogs.
- Bearers.
- Guardrails.
- Sills.
- Ledgers.
- Toeboards.
- Construction of scaffold?
Legs are the main vertical members.
Frames or standards (posts) are tied together by runners (beams) and
Braced by diagonals, spacers, crossbraces, and ties.
- Parts of scaffold?
- Base plate.
- Post or upright.
- Bearer (horizontal).
- Ledger brace.
- Cross bracing.
- Diagonal bracing.
- Platform.
- Guardrail.
- Toeboard.
- What is the most serious danger of scaffold work?
The danger of falling.
- Percentage account scaffold deaths on the job deaths in all construction?
6%.
- How many workers are injured every year in scaffold falls?
About 29,000.
- What cost most of scaffold catastrophes and fatalities and percentage of it?
Defective scaffolds, including those assembled with defective parts with account for 47%.
- How do we know a scaffold is safe?
- A solid foundation.
- Plumb, level, and square.
- Braced and solidly connected.
- All its parts - straight and undamaged.
- Fall protection - in the form of a guardrail system or a personal fall arrest system.
- Safe access.
- A safe platform.
- Who is responsible for properly erecting and inspecting the scaffold?
Qualified erectors for erecting and the competent person for inspection.
- What is a solid foundation?
Stable ground that will support 1,600 pound per square foot.
- What is heel test?
If a 180-pound worker can dig a heel 1 inch into the soil it is unstable.
- What are sills and mudsills in scaffolding?
At least 2x10” lumber in complete contact with the foundation. At least two scaffold legs should rest on one sill.
- How do scaffold legs attach to the sills?
Base plates or screw jacks should be centered on the sills and nailed in place. Nails should be in two corners opposite each other and bent over to lock the base plate to the sill.
- What is a base plate?
A piece of metal (6” square) that helps distribute the scaffold leg load over a larger area.
- What is a screw jack?
A mechanical device consisting of a threaded rod and a wing nut. It is used to level heavy loads. The screw jack attaches to the base plate.
- How do scaffold legs attach to the base plates?
With pins or locking devices.
- How do base plates or screw jacks attach to the sills?
They should be centered on the sills and nailed in place. Nails should be in two corners opposite each other and bent over to lock the base plate to the sill.
- How do we know a scaffold is plumb, level, and square?
Scaffold erectors use basic carpenter’s tools to check for plumb, level, and square. The competent person must make this check as well. You can make visual check to see if a scaffold is badly out of alignment.
- What parts should not a scaffold contain?
- Parts from another manufacture cannot be modified to fit a scaffold without the approval of a competent person.
- Parts made of dissimilar metals cannot be intermixed without the competent person’s approval.
- What is a brace?
A brace holds one scaffold member in a fixed position in relation to another. Bracing works horizontally or diagonally to reduce movement. They reduce sway and prevent collapse by keeping the frames square. OSHA requires braces on all supported scaffolds.
- Why are guardrails so important?
Guardrails prevent workers from falling off the scaffold.
- When does OSHA require guardrails around exposed sides and ends of scaffold platforms?
10’ or higher.
- How toprails must be?
38 to 45” above the working platform. They should be 2x4” lumber or equivalent metal or cable.
- When is cross-bracing acceptable as a toprail?
The crossing point of two braces is between 38” and 48” above the work platform.
- What is midra?
A barrier about halfway between the toprail and the toeboard. It must be 1x6” lumber or equivalent material.
- When is cross-bracing acceptable in place of a midrail?
The crossing point of the two place is between 20 and 30 “ above the platform.
- What are toeboards?
Vertical barriers at the exposed sides and ends of a scaffold platform. They must be at least 3 1/2” high.
- What must be in place if collected materials will be above toeboard height?
18 gauge US standard wire 1/2” mesh or equivalent must be in place between toeboardsj and toprails.