Powered Platforms
Chapter 296-870, WAC
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Effective
Date: 01/01/07 |
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IMPORTANT:
This section applies to permanent powered
platform installations that meet either of the following:
- Were completed after July 23, 1990
or
- Have had major modifications done to an existing
installation after July 23, 1990.
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Definition:
A new installation
is a permanent platform installation that was completed,
or an existing installation that has had major modifications
done, after July 23, 1990.
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Note:
If affected parts of the building meet
the requirements of the edition of American National Standard
Institute/American Society of Mechanical Engineers ANSI/ASME
A120.1, Safety Requirements for Powered Platforms for Building
Maintenance, that was in effect when the powered platform
installation was completed, they will be considered to meet
the requirements of this section. |
YOUR RESPONSIBILITY:
To make sure new
powered platform installations meet these building requirements
WAC 296-870-60005
Design
You must
- Make sure structural supports, tie-downs,
tie-in guides, anchoring devices and any affected parts of the
building included in the installation are designed by, or under
the direction of, a registered professional engineer experienced
in such design.
- Make sure affected parts of the building
are capable of sustaining all the loads imposed by the equipment.
- Make sure exterior installations are capable
of withstanding prevailing climatic conditions.
- Make sure the affected parts of the building
allow employees to use the equipment without being exposed to
a hazardous condition.
WAC 296-870-60010
Stabilization systems
You must
- Make sure the exterior of each building is
provided with at least one of the following stabilization systems:
- Continuous tie-in guides
- Intermittent stabilization system
- Button guide stabilization system
- System using angulated roping and building
face rollers
- System equivalent to a continuous tie-in
guide system
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Exemption:
- Tie-in guides may be eliminated for
not more than 75 feet (22.9 m) of the uppermost elevation
of the building if:
- Using tie-in guides there isn't
feasible due to building design
and
- Angulated roping is used that provides
a stabilizating force of at least 10 pounds (44.4
n) under all conditions of loading.
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You must
- Make sure embedded tie-down anchors,
fasteners, and affected structures are corrosion-resistant.
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Helpful Tool:
Typical examples of continuous external
or indented mullion guide, intermittent tie-in, and button
guide platform stabilization systems can be found in the
Resources section of this chapter. |
WAC 296-870-60015
Intermittent stabilization system
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Note:
This system may be used with a continuous
tie-in guide system on the same building as long as the
requirements for each system are met. |
You must
- Make sure an intermittent stabilization system:
- Keeps the equipment in constant contact
with the building
and
- Prevents sudden horizontal movement of
the platform.
- Make sure building anchors are located vertically
so that:
- The distance between anchors isn’t
more than 3 floors or 50 feet (15.3 m), whichever is less
and
- Attaching the suspension ropes to the
stabilizer ties won’t cause the platform to move horizontally
across the face of the building.
- Make sure the anchors are positioned horizontally
on the building face so as to be symmetrical about the platform
suspension ropes.
- Make sure building anchors:
- Are easily seen by employees
and
- Allow a stabilizer tie attachment for
each of the platform suspension ropes at each vertical interval.
- Make sure building anchors that extend
beyond the face of the building have no sharp edges or points.
- Make sure building anchors don’t interfere
with the handling or operation of cables, suspension wire ropes
and lifelines that may be in contact with the building face.
- Make sure the building anchors and components
can sustain, without failure, at least 4 times the maximum anticipated
load applied or transmitted to them.
- Make sure the building anchors and stabilizer
ties can sustain the anticipated horizontal and vertical loads
from winds specified for roof storage design which may act on
the platform and wire ropes if the platform is stranded on the
building face.
- Make sure the minimum design wind load for
each anchor is 300 pounds (1334 n) if 2 anchors share the wind
load.
- Make sure one building anchor and stabilizer
tie can sustain the wind load if either:
- The building anchors have different spacing
than the suspension wire rope
or
- The building requires different suspension
spacings on one platform.
WAC 296-870-60020
Button guide stabilization system
You must
- Make sure the guide buttons are:
- Coordinated with the platform guide
tracks and other platform-mounted equipment
and
- Located on the building so they properly
engage the guide tracks mounted on the platform.
- Make sure 2 guide buttons engage each guide
track at all times except for the initial engagement.
- Make sure guide buttons that extend beyond
the face of the building have no sharp edges or points.
- Make sure guide buttons don’t interfere
with the handling or operation of cables, suspension wire ropes
and lifelines that may be in contact with the building face.
- Make sure guide buttons, connections, and
seals are either:
- Able to sustain, without damage, at least
the weight of the platform
or
- Are prevented by the guide tracks or
guide track connectors from having the weight of the platform
and its attachments transmitted to them.
WAC 296-870-60025
Stabilization system using angulated roping
and building face rollers
You must
- Make sure a stabilization system using angulated
roping and building face rollers does all of the following:
- Keeps the equipment in continuous contact
with the building face
- Prevents sudden horizontal movement of
the platform
- Maintains a stabilizing force of at least
10 pounds (44.4 n) against the face of the building.
- Make sure the suspended portion of the equipment
isn’t used more than 130 feet (39.6 m) above a safe surface
or ground level.
WAC 296-870-60030
Cable stabilization
You must
- Make sure hanging lifelines and all other
cables not in tension are stabilized after the initial 200 feet
(61 m) of vertical travel of the working platform and every
200 feet (61 m) thereafter.
- Make sure hanging cables which are in constant
tension, other than suspended wire ropes, are stabilized after
an initial 600 feet (183 m) of vertical travel of the working
platform and at intervals of 600 feet (183 m) or less thereafter.
WAC 296-870-60035
Electrical
You must
- Make sure, when full load is applied
to the equipment power circuit, that the building electrical
wiring doesn’t allow more than a 5 percent voltage drop
from the building service vault voltage at any power circuit
outlet used by the powered platform installation.
- Make sure the equipment power circuit is
provided with a disconnect switch that’s all of the following:
- Able to be locked in either the “off”
or “on” position
- Conveniently located with respect to
the primary operating area of the equipment to allow equipment
operators access to the switch
- Locked in the “on” position
when the equipment is being used.
- Make sure the powered platform equipment
power supply is an independent electrical circuit that remains
separate from all other equipment within or on the building.
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Exemption:
The equipment power circuit may be connected
to the electrical circuit supplying power to hand tools
used in conjunction with the equipment. |
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Note:
If the building is provided with an emergency
power system, the equipment power circuit may also be connected
to the emergency power system. |
WAC 296-870-60040
Guarding roofs and other elevated areas
You must
Make sure employees working on a roof or other elevated working
area 4 feet (1.2 m) or more above an adjacent safe surface are
protected by a perimeter guarding system.
You must
- Make sure the inboard face of the perimeter
guard is:
- Not more than 6 inches (152 mm) inboard
of the inside face of a barrier such as the parapet wall
or roof edge curb;
and
- Not more than 18 inches (457 mm) from
the face of the building.
- Make sure an elevated track system that’s
designed to be traversed by carriage-supported equipment and
located 4 feet (1.2 m) or more above an adjacent safe surface
is either:
- Provided with a walkway and guardrail
system;
or
- Has a working platform that can be lowered,
as part of normal operations, to the lower safe surface.
- Make sure personnel have a safe way to access
and to egress from the lower safe surface.
WAC 296-870-60045
Moving equipment
You must
- Make sure all carriages and carriage-supported
equipment can be traversed to a safe area for storage and maintenance.
- Make sure operational areas for trackless
type equipment have structural stops, such as curbs, to prevent
equipment from traveling outside its intended travel area.
WAC 296-870-60050
Repair and maintenance
You must
- Make sure repair or major maintenance of
parts of the building that provide primary support for suspended
equipment doesn’t affect the ability of the building to
meet the requirements of this chapter.
WAC 296-870-60055
Communications
You must
- Make sure an effective 2-way voice communication
system is provided between the equipment operators and persons
stationed within the building.
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