Powered Platforms
Chapter 296-870, WAC
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Effective
Date: 01/01/07 |
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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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