Powered Platforms

Chapter 296-870, WAC

Effective Date: 01/01/07

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WAC 296-870-800

Definitions

For printing

Anemometer

An instrument for measuring wind velocity.

Angulated roping

A suspension method where the upper point of suspension is inboard from the attachments on the suspended unit, thus causing the suspended unit to bear against the face of the building.

Building face rollers

A specialized form of guide roller designed to ride on the face of the building wall to prevent the platform from abrading the face of the building and to assist in stabilizing the platform.

Building maintenance

Operations such as window cleaning, caulking, metal polishing, reglazing, and general maintenance on building surfaces.

Cable

A conductor, or group of conductors, enclosed in a weatherproof sheath, that may be used to:

  • - Supply electrical power or control current for equipment
    or
  • - Provide voice communication circuits.

Carriage

A wheeled vehicle used for the horizontal movement and support of other equipment.

Certification

A written, signed, and dated statement confirming the performance of a requirement.

Combination cable

A cable having both steel structural members capable of supporting the platform, and copper or other electrical conductors insulated from each other and the structural members by nonconductive barriers.

Competent person

Someone who:

- Is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees
and
- Has the authority to take prompt corrective measures to eliminate them.

Continuous pressure

Operation of a control by requiring constant manual actuation for the control to function.

Control

A system or mechanism used to regulate or guide the operation of equipment.

Davit

A device, used singly or in pairs, for suspending a powered platform from work, storage and rigging locations on the building being serviced. Unlike outriggers, a davit reacts its operating load into a single roof socket or carriage attachment.

Design factor

The ratio of the rated strength of the suspension wire rope to the rated working load. It’s calculated using the following formula:

F= (SxN)/W Where:

F=Design factor
S=Manufacturer's rated strength of one suspension rope
N=Number of suspension ropes under load

W= Rated working load on all ropes at any point of travel.

Equivalent

Alternative design, material or method to protect against a hazard. You have to demonstrate it provides an equal or greater degree of safety for employees than the method, material or design specified in the rule.

Existing installation

A permanent powered platform installation that:

- Was completed before July 23, 1990

and

- Has had no major modification done after July 23, 1990.

Ground rigging

A method of suspending a working platform starting from a safe surface to a point of suspension above the safe surface.

Ground rigged davit

A davit which can’t be used to raise a suspended working platform above the building face being serviced.

Guide button

A building face anchor designed to engage a guide track mounted on a platform.

Guide roller

A rotating cylindrical member that provides continuous engagement between the suspended or supported equipment and the building guides. It may operate separately or as part of a guide assembly.

Guide shoe

A device that’s similar to a guide roller but is designed to provide a sliding contact between the shoe and the building guides.

Hoisting machine

A device intended to raise and lower a suspended or supported unit.

Installation

A powered platform installation consists of all the equipment and the parts of the building involved with using the powered platform for building maintenance.

Interlock

A device designed to ensure that operations or motions occur in proper sequence.

Intermittent stabilization

A method of platform stabilization in which the angulated suspension wire ropes are secured to regularly spaced building anchors.

Lanyard

A flexible line of rope, wire rope or strap which is used to secure the body harness to a deceleration device, lifeline or anchorage.

Lifeline

A component consisting of a flexible line that connects to an anchorage at one end to hang vertically (vertical lifeline), or that connects to anchorages at both ends to stretch horizontally (horizontal lifeline). It serves as a means for connecting other components of a personal fall arrest system to the anchorage.

Live load

The total static weight of workers, tools, parts, and supplies that the equipment is designed to support.

New installation

A permanent powered platform installation that was completed, or an existing installation that has had major modifications done, after July 23, 1990.

Operating control

A mechanism regulating or guiding the operation of equipment that makes sure the equipment operates in a specific mode.

Operating device

A push button, lever, or other manual device used to actuate a control.

Outrigger

A device, used singly or in pairs, for suspending a working platform from work, storage, and rigging locations on the building being serviced. Unlike davits, an outrigger reacts its operating moment load as at least two opposing vertical components acting into two or more distinct roof points and/or attachments.

Poured socket

A method of providing wire rope termination in which the ends of the rope are held in a tapered socket by means of poured spelter or resins.

Primary brake

A brake designed to be applied automatically whenever power to the prime mover is interrupted or discontinued.

Prime mover

The source of mechanical power for a machine.

Rated load

The manufacturer's specified maximum load.

Rated strength

The strength of wire rope, as designated by its manufacturer or vendor, based on standard testing procedures or acceptable engineering design practices.

Rated working load

The combined static weight of workers, materials, and suspended or supported equipment.

Registered professional engineer

A person who has been duly and currently registered and licensed by an authority within the United States or its territories to practice the profession of engineering.

Roof-powered platform

A powered platform having the raising and lowering mechanism located on the roof.

Roof-rigged davit

A davit used to raise the suspended working platform above the building face being serviced. This type of davit can also be used to raise a suspended working platform which has been ground rigged.

Rope

The equipment, such as wire rope, that’s used to suspend a component of an equipment installation.

Safe surface

A horizontal surface that provides reasonable assurance that personnel occupying the surface will be protected from falls. This protection can be provided by location, a fall protection system, or other equivalent method.

Secondary brake

A brake designed to arrest the descent of the suspended or supported equipment in the event of an overspeed condition.

Stability factor

The ratio of the stabilizing moment to the overturning moment.

Stabilizer tie

A flexible line connecting the building anchor and the suspension wire rope supporting the platform.

Supported equipment

Building maintenance equipment that’s held in or moved to its working position by means of attachment directly to the building or extensions of the building being maintained.

Suspended equipment

Building maintenance equipment that’s suspended and raised or lowered to its working position by means of ropes or combination cables attached to some anchorage above the equipment.

Tie-in guides

The portion of a building that provides continuous positive engagement between the building and a suspended or supported unit during its vertical travel on the face of the building.

Transportable outriggers

Outriggers designed to be moved from one work location to another.

Type F powered platform

A powered platform that has both of the following characteristics:

- The working platform is suspended by at least 4 wire ropes and designed so that failure of any one wire rope won’t substantially alter the normal position of the working platform
- Only one layer of hoisting rope is permitted on the winding drums.

Type T powered platform

A powered platform installation that has a working platform suspended by at least 2 wire ropes. The platform won’t fall to the ground if a wire rope fails, but the working platform's normal position would be upset.

Weatherproof

Constructed or protected so that exposure to the weather won’t interfere with successful operation.

Winding drum hoist

A type of hoisting machine that accumulates the suspension wire rope on the hoisting drum.

Working platform

The suspended or supported equipment intended to provide access to the face of the building and manned by persons engaged in building maintenance.

Wrap

One complete turn of the suspension wire rope around the surface of a hoist drum.

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