WAC 296-874-300 Suspended Scaffolds

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Your Responsibility

To meet these requirements when using suspended scaffolds

WAC 296-874-30002

Make sure suspended scaffolds and scaffold components meet these strength requirements

You must

• Meet the following strength requirements:
• - Suspended scaffolds must support, without failure, the total of their own weight plus 4 times the maximum intended load
• – Suspended scaffold components must meet the requirements contained in Table 4, Suspended Scaffold Strength Requirements.
• Surfaces that support scaffold support devices must withstand 4 times the rated load of the hoist:

You must

WAC 296-874-30004

Make sure suspended scaffold outrigger beams meet these requirements

You must

• Make sure outrigger beams are made of structural metal or equivalent strength material.
• Stabilize the inboard ends of outrigger beams by using either:
• – Bolts or other direct connections to the floor or roof deck
• or
• – Counterweights and tiebacks.

Exemption: Masons’ multi-point adjustable scaffold outrigger beams can not be stabilized by counterweights.

You must

• Make sure, before the scaffold is used, that a competent person:
• – Evaluates the direct connections
• and
• – Confirms that the supporting surfaces can support the loads placed on them.
• Make sure suspended scaffold outrigger beams are all of the following:
• – Restrained to prevent moving
• – Provided with stop bolts or shackles at both ends
• – Securely fastened together with the flanges turned out when channel iron beams are used in place of I-beams
• – Set and maintained with the web in a vertical position
• – Placed so the suspension rope is centered over the stirrup.
• Place outrigger beams at a right angle (perpendicular) to their bearing support.

Exemption: Outrigger beams can be placed at other than a right angle (perpendicular) if: - You can demonstrate that immovable obstructions make it impossible to place the beams at a right angle (perpendicular) to their bearing support and - Opposing angle tiebacks are used.

WAC 296-874-30006

Make sure counterweights are safe and used properly

You must

• Make sure counterweights:
• – Are made of material that can't flow
  and
• – Have been specifically designed to be used as counterweights.

You must

• Secure counterweights to outrigger beams by mechanical means to prevent them from being accidentally detached.
• Leave counterweights attached to the outrigger beams until after the scaffold has been disassembled

WAC 296-874-30008

Make sure tiebacks meet these requirements

You must

• Make sure tiebacks are equivalent in strength to the suspension ropes.
• Make sure tiebacks are secured to a structurally sound anchorage on the building or structure and installed:
• – At a right angle (perpendicular) to the face of the building or structure
  or
• – As opposing angle tiebacks.

WAC 296-874-30010

Make sure suspended scaffold support devices meet these requirements

You must

• Make sure suspended scaffold support devices, such as cornice hooks, roof hooks, roof irons, parapet clamps, or similar devices, are:
  • – Made of steel, wrought iron, or other material of equivalent strength
  • – Supported by bearing blocks
  • – Prevented from moving by using tiebacks.

WAC 296-874-30012

Make sure scaffold hoists meet these requirements

You must

• Make sure the stall load of any scaffold hoist is not more than 3 times its rated load.
• Make sure the design of scaffold hoists has been tested by an independant nationally recognized testing laboratory.
• Make sure scaffold hoists have both a:
• – Normal operating brake
• and
• – Braking device or locking pawl which automatically engages when the hoist has an uncontrolled:
• Instantaneous change in momentum
  or
• An accelerated overspeed.
• Prohibit use of gasoline-powered hoists on suspended scaffolds.
• Enclose the gears and brakes of power-operated hoists used on suspended scaffolds.
• Make sure manually-operated hoists need a positive crank force to descend.

WAC 296-874-30014

Make sure scaffold hoists retain enough suspension rope

You must

• Make sure the suspension rope on winding drum hoists is long enough to wrap around the drum at least 4 times when the scaffold is at its lowest point of travel.
• Make sure the suspension rope on hoists that do not use a winding drum:
• – Is long enough to allow the scaffold to be lowered to the level below without the rope end passing through the hoist
  or
• – Has the rope end configured, or uses other means, to prevent it from passing through the hoist.

WAC 296-874-30016

Make sure wire rope is in good condition

You must

• Make sure a competent person inspects each rope for defects:
  • – Before each work shift
    and
  • – After anything happens that could affect the rope’s integrity.
• Replace a rope if it has any of the following:
  • – Physical damage which impairs the function and strength of the rope
  • – Kinks that could impair the tracking or wrapping of the rope around a drum or sheave
  • – 6 randomly distributed broken wires in one rope lay
  • – 3 broken wires in one strand of one rope lay
  • – Loss of more than 1/3 of the original diameter of the outside wires caused by abrasion, corrosion, scrubbing, flattening or peening
  • – Heat damage caused by a torch
  • – Any damage caused by contact with electrical wires
  • – Evidence that the secondary brake has been activated during an overspeed condition and has engaged the suspension rope.
• Prohibit the use of repaired wire rope as suspension rope.

WAC 296-874-30018

Make sure wire suspension rope connections meet these requirements

You must

• Only use eye splice thimbles connected with shackles or cover plates and bolts to join wire suspension ropes together.
• Make sure the load ends of wire suspension ropes are:
• – Equipped with proper size thimbles
• – Secured by eye splicing or an equivalent means.
• Make sure all swaged attachments or spliced eyes on wire suspension rope has been made by either:
• – The wire rope manufacturer
  or
• – A qualified person.

WAC 296-874-30020

Make sure wire rope clips are used properly

You must

• Make sure, if wire rope clips are used on suspended scaffolds, such as on the suspension ropes or support lines, that:
  • – A minimum of 3 clips are installed
  • – The distance between clips is at least 6 rope diameters
  • – Clips are installed according to the manufacturer’s recommendations.
• Retighten the clips to the manufacturer’s recommendations after the initial loading.
• Inspect the clips and retighten them to the manufacturer’s recommendations at the start of each work shift.
• Make sure U-bolt clips aren't used at the point of suspension for any scaffold hoist.
• Make sure, if U-bolt clips are used, that:
  • – The U-bolt is placed over the dead end of the rope
    and
  • – The saddle is placed over the live end of the rope.

WAC 296-874-30022

Prevent swaying of two-point and multi-point suspension scaffolds

You must

• Tie or use other means to keep two-point and multi-point suspension scaffolds from swaying, if an evaluation by a competent person determines it is necessary.

WAC 296-874-30024

Use emergency escape and rescue devices appropriately

You must

• Make sure devices whose sole function is to provide emergency escape and rescue aren't used as working platforms.

WAC 296-874-30026

Protect suspension ropes from heat or corrosive substances

You must

• Shield suspension ropes from heat-producing processes.
• Make sure, when acids or other corrosive substances are used on a scaffold, that the suspension ropes are protected by at least one of the following:
• – Shielding
• – Treating to protect the rope from the corrosive substances
• – Making the rope of material that the corrosive substance won't damage.

WAC 296-874-30028

Take precautions while welding

You must

• Do the following to protect employees while welding on suspended scaffolds:
• – Use an insulated thimble to attach each suspension wire rope to its hanging support, such as a cornice hook or outrigger
• – Insulate excess suspension wire rope and any additional independent lines to prevent grounding
• – Cover the wire suspension rope with insulating material that extends at least 4 feet (1.2 m) above the hoist
• – Make sure any tail line that extends below the hoist is:
• Insulated to prevent contact with the platform
  and
• Guided or retained so it doesn't become grounded.
• – Cover each hoist with an insulated protective cover
• – Connect the scaffold to the structure using a grounding conductor that:
• Is at least the size of the welding process work lead
  and
• Isn't in series with the welding process or the work piece.
• – Shut off the welding machine if the scaffold grounding lead becomes disconnected
• – Make sure an active welding rod or an uninsulated welding lead isn't allowed to contact the:
• Scaffold
  or
• Scaffold suspension system.

WAC 296-874-30030

Prohibit use of gasoline-powered equipment on suspended scaffolds

You must

• Make sure gasoline-powered equipment is not used on suspended scaffolds.

WAC 296-874-30032

Meet these requirements when using catenary scaffolds

You must

• Make sure catenary scaffolds have:
• – No more than one platform between consecutive vertical pickups
  and
• – No more than 2 platforms per scaffold.
• Make sure any platform that’s supported by wire ropes has hook-shaped stops placed at each end of the platform that will prevent it from falling if one of the horizontal wire ropes breaks.
• Make sure wire ropes are:

  • – Continuous and without splices between anchors
    and
    – Not tightened to the point that putting a load on the scaffold will overstress them.

WAC 296-874-30034

Meet these requirements when using float (ship) scaffolds

You must

• Support the platform with at least 2 bearers.
• Make sure each bearer:
  • – Projects at least 6 inches (15.2 cm) beyond the platform on both sides
    and
  • – Is securely fastened to the platform.
• Make sure rope connections won’t allow the platform to shift or slip.
• Make sure scaffolds that only have 2 ropes used with each float meet all of the following:
• – There are 4 rope ends that are securely fastened to overhead supports
• – Each supporting rope is hitched around one end of the bearer, passed under the platform to the other end of the bearer, and hitched again
• – There is enough rope at each end for the supporting ties.

WAC 296-874-30036

Meet these requirements when using interior hung scaffolds

You must

• Suspend the scaffold only from the roof structure or other structural member, such as ceiling beams.
• Inspect the overhead supporting members and check to make sure they’re strong enough before erecting the scaffold.
• Connect suspension ropes and cables to the overhead supporting members by:
• – Shackles, clips, or thimbles
  or
• – Other means that meet equivalent criteria, such as strength and durability.

WAC 296-874-30038

Meet these requirements when using multi-level suspended scaffolds

You must

• Equip scaffolds with additional independent support lines that meet all of the following:
• – There are the same number of support lines as there are connection points for the suspension ropes
• – The support lines are equivalent in strength to the suspension ropes
• – The support lines are rigged to support the scaffold if the suspension ropes fail.
• Make sure the independent support lines and the suspension ropes aren't attached to the same points of anchorage.
• Attach platform supports directly to the support stirrup and not to another platform.

WAC 296-874-30040

Meet these requirements when using multi-point adjustable suspension scaffolds

IMPORTANT:

• This requirement applies when using multi-point adjustable suspension scaffolds, stonesetters’ multi-point adjustable suspension scaffolds, and masons’ multi-point adjustable suspension scaffolds.

You must

• Make sure masons’ multi-point adjustable suspension scaffold connections are designed by an engineer experienced in designing this type of scaffold.
• Make sure bridges between 2 or more scaffolds meet all of the following:
• – The scaffolds were designed to be bridged
• – The bridges are articulated
• – The hoists are properly sized.
• Make sure passage from one platform to another, without using bridges, is done only when the platforms are:
• – At the same height
  and
• – Abutting.
• Suspend scaffolds from:
  • – Metal outriggers, brackets, wire rope slings, or hooks
    or
  • – Other means that meet equivalent criteria, such as strength and durability.

WAC 296-874-30042

Meet these requirements when using needle beam scaffolds

You must

• Install scaffold support beams on edge
• Use ropes or hangers for scaffold supports
• – One end of a needle beam scaffold may be supported by a permanent structural member.
• Securely attach ropes to the needle beams.
• Arrange the support connection to prevent the needle beam from rolling or becoming displaced.
• Securely attach platform units to the needle beams with bolts or equivalent means.

WAC 296-874-30044

Meet these requirements when using single-point adjustable suspension scaffolds

You must

• Make sure 2 scaffolds that have been combined to form a two-point adjustable suspension scaffold meet the requirements of the section, Make sure two-point adjustable suspension scaffolds (swing stages) meet these requirements, WAC 296-874-30046.
• Make sure scaffolds, where the suspension rope between the scaffold and the suspension device isn't vertical, meet all of the following:
• – The rigging has been designed by a qualified person
• – The scaffold is accessible to rescuers
• – The suspension rope is protected from chafing at any point where it changes direction
• – The scaffold is positioned so that swinging can't bring the scaffold into contact with another surface.
• Make sure boatswains’ chair tackle meets of all of the following:
• – It consists of correct size ball bearing blocks or bushed blocks
• – The blocks contain safety hooks
• – The rope is properly eye-spliced
• – The rope is either:
• First-grade manila rope that has a diameter of at least 5/8 inch (1.6 cm)
  or
• Other rope that has equivalent characteristics, such as strength and durability.

• Make sure boatswain's chair seat slings meet all of the following:
• – Are reeved through 4 corner holes in the seat
• – Cross each other on the underside of the seat
• – Are rigged to prevent slipping which could cause the seat to become out-of-level
• – Are made from fiber, synthetic, or other rope which have:
  • A diameter of at least 5/8 inch (1.6 cm)
    and
  • Characteristics equivalent to first grade manila rope, such as strength, slip resistance, and durability.
• Make sure the seat sling of boatswain's chairs used when a heat-producing process, such as gas or arc welding, is being conducted, is at least 3/8 inch (1.0 cm) wire rope.
• Securely fasten cleats to the underside of noncross-laminated wood boatswain's chairs to prevent the board from splitting.

WAC 296-874-30046

Meet these requirements when using two-point adjustable suspension scaffolds (swing stages)

IMPORTANT:

• This section doesn't apply to two-point adjustable suspension scaffolds used as masons’ or stonesetters’ scaffolds.

You must

• Make sure platforms more than 36 inches (0.9 m) wide have been designed by a qualified person to prevent unstable conditions.
• Make sure platforms are one of the following:
  • – Ladder-type
  • – Plank-type
  • – Beam-type
  • – Light-metal type.
• Make sure the design of light-metal type platforms have been tested and listed by a nationally recognized testing laboratory if they:
  • – Have a rated capacity of 750 lbs. or less
    or
  • – Have a length of 40 feet (12.2 m) or less.

• Securely fasten the platform to the hangers (stirrups) using U-bolts or other means that satisfy the section titled, Make sure suspended scaffolds and scaffold components meet these strength requirements, WAC 296-874-30002.
• Make sure fiber or synthetic ropes are used with blocks that:
  • – Consist of at least one double and one single block
    and
  • – Have sheaves that fit the size of the rope used.
• Make sure employees move from one platform to another only when all of the following are met:
  • – The platforms are at the same height
  • – The platforms are abutting
  • – Walk-through stirrups are used that have been specifically designed to allow employee passage.
• Make sure two-point scaffolds that are bridged or otherwise connected together when being raised or lowered meet both of the following:
  • – The bridge connections are articulated
  • – The hoists are properly sized.