Permanent scaffolds or platforms should be installed on all buildings exceeding 130’- 0” feet (40 m) in height.
Cal-OSHA Ruling on Platforms
When using a permanent powered scaffold for window cleaning applications, its design, use and maintenance shall comply with the provisions of General Industry Safety Order (GISO Article 6. Section 5, Window Cleaning. All anent scaffold installations installed prior to July 1, 1993 and after September 29, 1974 shall comply with all provisions of Article 6, Appendix D. Permanent scaffolds installed prior to September 29, 1974 shall be inspected, tested and maintained in accordance with the provisions of Article 6, Appendix D.
-Employees should be trained by a competent person in the use and care of suspended scaffolds before use.
-It is the building owner, manager or operating agents’ responsibility to have the permanent powered scaffold inspected on an annual basis, prior to use and after every 30 day cycle of usage. A copy of the inspection is to be given to the window cleaning contractor before use.
-Workers should continuously monitor the components of the scaffold while operating it.
Permanent scaffolds are or can be equipped with added safety features over and above that required for non-permanent platforms in compliance with OSHA 1910.66, Support F e.g. tall stirrup design which provides a means of suspension to restrict platform inboard to outboard roll, screened in platform, stabilizer tie-in devices, fire extinguisher, building face rollers, casters, power cable bin, and primary cable wire winders. Permanent scaffolds should be equipped with a wind sway protection system if dropping from heights above 130’-0” feet (40 m). An emergency action plan is also required.
Electrical power outlets are to be located on each roof level no more than 100’-0” (30 m) from window cleaning/suspended equipment locations. Permanent powered scaffolds require 230 volts. The outlets should not experience more than 3% voltage drop under full load.
Permanent scaffolds are also equipped with added electrical safety features e.g. 3 phase reversal and phase failure, upper limit control device, slack wire rope device, overload limiting device and lateral leveling.
Normally a modular-type platform, permanent platforms are usually manufactured aluminum and are available in connectable sections designed to suit building platform “drops.” Accessories include: building face rollers to protect the building face; special adjustable roller or caster systems for use on sloping glass surfaces; and walk-through type stirrups to extend platform beyond suspension points.
Steel cable primary suspension lines are attached to primary suspension supports on the roof. ‘T’ type platforms employ two-cable suspension with separate fall arrest lifelines tied off to their own independent rooftop safety anchors. ‘F’ type platforms employ four-cable suspension with fall arrest lanyards secured to the platform (no separate hanging lifelines).
‘T’ type platforms are more commonly used for window cleaning on buildings under 130’-0” (40 m). Type ‘F’ platforms are more commonly used on buildings over 130’-0” (40 m) due to concerns for weight and stabilization of hanging lines i.e. wind hazard.
Permanent powered scaffolds are mandatory in California State for buildings of 130’-0” (40 m) height or higher.