Labor & Industries (L&I), Washington State

Scaffolds Chapter 296-874, WAC

Effective Date: 10/06/07

WAC 296-874-300 Suspended Scaffolds

For printing

Your Responsibility

To meet these requirements when using suspended scaffolds

Make sure suspended scaffolds and scaffold components meet these strength requirements	WAC 296-874-30002
Make sure suspended scaffold outrigger beams meet these requirements	WAC 296-874-30004
Make sure counterweights are safe and used properly	WAC 296-874-30006
Make sure tiebacks meet these requirements	WAC 296-874-30008
Make sure suspended scaffold support devices meet these requirements	WAC 296-874-30010
Make sure scaffold hoists meet these requirements	WAC 296-874-30012
Make sure scaffold hoists retain enough suspension rope	WAC 296-874-30014
Make sure wire rope is in good condition	WAC 296-874-30016
Make sure wire suspension rope connections meet these requirements	WAC 296-874-30018
Make sure wire rope clips are used properly	WAC 296-874-30020
Prevent swaying of two-point and multi-point suspension scaffolds	WAC 296-874-30022
Use emergency escape and rescue devices appropriately	WAC 296-874-30024
Protect suspension ropes from heat or corrosive substances	WAC 296-874-30026
Take precautions while welding	WAC 296-874-30028
Prohibit use of gasoline-powered equipment on suspended scaffolds	WAC 296-874-30030
Meet these requirements when using catenary scaffolds	WAC 296-874-30032
Meet these requirements when using float (ship) scaffolds	WAC 296-874-30034
Meet these requirements when using interior hung scaffolds	WAC 296-874-30036
Meet these requirements when using multi-level suspended scaffolds	WAC 296-874-30038
Meet these requirements when using multi-point adjustable suspension scaffolds	WAC 296-874-30040
Meet these requirements when using needle beam scaffolds	WAC 296-874-30042
Meet these requirements when using single-point adjustable suspension scaffolds	WAC 296-874-30044
Meet these requirements when using two-point adjustable suspension scaffolds (swing stages)	WAC 296-874-30046

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:

Note: Scaffold support devices include outrigger beams, cornice hooks, parapet clamps, and similar devices.

You must

Table 4 Suspended Scaffold Strength Requirements
These scaffold components	Must meet these strength requirements
Adjustable scaffold – Suspension ropes, including connecting hardware	Support 6 times the rated load of the hoist
Adjustable scaffold – Direct connections to roofs and floors – Counterweights used to balance the scaffold	Resist 4 times the tipping moment with the scaffold operating at the rated load of the hoist
Non-adjustable scaffold – Suspension ropes, including connecting hardware	Support 6 times the maximum intended load applied or transmitted to the rope
All other scaffold components	Support its own weight plus 4 times the maximum intended load

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.

Note: The angle between the outrigger beam and the bearing support is usually the same as the angle between the outrigger beam and the face of the building or structure.

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.

Note: The following can't be used as counterweights: - Sand, gravel and similar materials that can be easily dislocated and - Construction material such as masonry units and roofing felt.

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.

Reference: For outrigger beam requirements, go to WAC 296-874-30004. For tieback requirements, go to WAC 296-874-30008.

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.

Note: Window cleaners’ anchors cannot be used to secure scaffolds since they aren't designed to withstand the load.

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.

Note: Systems which are designed to function both as suspended scaffolds and emergency systems may be 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.

Reference: For specific fall protection requirements for employees on catenary scaffolds, go to WAC 296-874-20056.

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.

Reference: For specific fall protection requirements for employees on float (ship) scaffolds, go to WAC 296-874-20056.

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.

Note: Cleats and overhang aren't adequate means of attachment.

Reference: For specific fall protection requirements for employees on needle beam scaffolds, go to WAC 296-874-20056.

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.

Reference: For specific fall protection requirements for employees on single-point adjustable suspension scaffolds, go to WAC 296-874-20056.

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.

Reference: For requirements for masons’ or stonesetters’ scaffolds, go to WAC 296-874-30040

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.

Reference: For specific fall protection requirements for employees on two-point adjustable suspension scaffolds, go to WAC 296-874-20056.