SWP types, configurations and terminology
Domain 2 tests vocabulary and configuration: can you name the parts of a suspended working platform, describe how it is supported, and explain why each part exists?
The platform
A temporary suspended working platform (TSWP) is the statutory term; gondola is the trade name. The cradle is the working deck, normally modular aluminium or steel, with a floor, guardrails (top rail about 1.0 m with a mid-rail), toe boards at least 150 mm, end gates and a nameplate showing the rated load and maximum number of persons.
Suspension configurations
- Two-point (dual-point) suspension - the standard configuration; the cradle hangs from two independent suspension wire ropes, one at each end, each with its own hoist.
- Single-point suspension - the cradle hangs from one suspension point; it needs anti-rotation restraint and a tag line, and is used only for limited access.
- Roof rig - the whole assembly on the roof: outrigger beams, counterweights, tie-backs, parapet clamps, suspension ropes and anchors.
- Davit arms, monorail and crane-suspended platforms - alternatives where a conventional roof rig cannot be used.
Components and why they matter
- Outrigger beam: projects over the edge; its overhang and back-span set the load on the roof.
- Counterweight: calculated mass fixed to the inboard end. It must be purpose-made, marked and secured - never bricks, sandbags or loose weights.
- Tie-back: rope or rod from the rig to a structural anchor, resisting the outboard tipping moment.
- Parapet clamp: holds the rig laterally; it is not a tie-back and does not replace counterweights.
- Suspension wire rope: carries the cradle; terminated with a thimble and the correct number of clips, or a swaged fitting.
- Safety rope: an independent lifeline, anchored separately from the rig, for the fall arrest device.
- Fall arrest system: full-body harness, energy-absorbing lanyard and rope grab.
Worked example
You are shown a rig with two beams, purpose-made counterweights chained to the inboard ends, two tie-backs to cast-in eye bolts, two suspension ropes and two safety ropes anchored to separate structural points. This is a two-point suspension roof rig. The tie-backs and separate safety-rope anchors are what make it acceptable; if the safety ropes were clipped to the rig, the arrangement would fail.
Traps
- Calling the safety rope a suspension rope.
- Thinking a parapet clamp is an anchor.
- Describing single-point suspension as the normal configuration.
- Forgetting that the nameplate states both load and persons.