512 EM 385-1-1 Chapters 16-22

Sections

22-8. General Requirements.

Metal Scaffolds and Towers General Requirements

Do not combine scaffold components of different metals unless a Competent Person (CP) approves.
Ensure metal scaffold sections and braces are securely connected.
Provide safe, stable access to metal scaffolds using ladders or stairways.

Tube and Coupler Scaffolds

Use materials and dimensions for posts, runners, and bracing as per ANSI A10.8 standards or equivalent.
Adhere to height and working level restrictions as specified in ANSI A10.8 unless designed by a Registered Professional Engineer (RPE).
Tube and coupler scaffolds must have posts, runners, and bracing of nominal 2 inches outside diameter steel tubing or pipe, or if other structural metals are used, they must be designed to carry an equivalent load.
Ensure scaffolds can support four times the maximum intended load or as specified by an RPE.

Fabricated Frame Scaffolds

Align frames and panels to withstand loads, securing them with braces to maintain scaffold stability.
Set scaffold legs on firm bases and stack frames securely with alignment pins.
For scaffolds over 125 feet high, obtain designs from an RPE.

Manually Propelled Mobile Scaffolds

Equip wheels and casters with locks to prevent accidental movement.
Use scaffolds on firm, level, and clean surfaces, ensuring the platform height is within safety limits.
Do not allow riding on scaffolds unless specific safety conditions are met.

Suspended Scaffolds

Follow the operating manual for design, construction, operation, inspection, testing, and maintenance.
Ensure all scaffold parts have a minimum safety factor of four, with support ropes having a factor of six.
Secure suspension scaffold support devices and outrigger beams on strong, stable surfaces with proper tiebacks and counterweights.

Hoisting Machines on Suspended Scaffolds

Use only hoisting machines tested and listed by a Nationally Recognized Testing Laboratory (NRTL), ensuring they have speed reducers and primary and secondary brakes.
Provide separate controls for each powered hoist, with provisions for manual operation if designed accordingly.
For manually operated hoists, ensure safety mechanisms are in place to prevent rapid un-spooling and descent.

Working Surfaces on Suspended Scaffolds

Use only tested and listed light metal platforms or properly secured planking, avoiding ladder-type and beam platforms.
Prevent scaffold swaying by using guy, brace, guide, or tag lines.
Ensure two-point suspension scaffold platforms are within specified width, securely fastened, and properly supported and lashed.

Load Capacities and Specific Scaffold Types

Adhere to weight limits and number of workers allowed on suspension scaffolds.
Provide overhead protection and ensure load capacity for Mason's Multiple-Point Adjustable Suspension Scaffolds.
Design and use Stonesetters' multiple-point adjustable suspension scaffolds in accordance with ANSI A10.8.

Knowledge Check Choose the best answer for the question.

22-7. If tube and coupler scaffolds use steel tubing or pipe, the posts, runners, and bracing must have an outside diameter of _____.

1 to 3 inches

2 inches

2 to 3 inches

3 inches

You forgot to answer the question!

EM 385-1-1 Paragraph 22-8 (d.–f.).

22-8. General Requirements. (d.–f.).

d.  Metal Scaffolds and Towers.  (22-8.d)

(1)  General Requirements:

(a)  Do not use scaffold components made of dissimilar metals together unless a CP has determined that galvanic action will not reduce the strength of any component to a level below that required by paragraph 22-8.c.

(b)  Securely connect the sections of metal scaffolds and securely fasten all braces.

(c)  Provide a ladder or stairway for access that is affixed or built into the metal scaffolds. Position the ladder or stairway so that when in use it will not have a tendency to tip the scaffold.

(2) Tube and Coupler Scaffolds (see 29 CFR 1926.452).

(a) Tube and coupler scaffolds must have posts, runners, and bracing of nominal 2 inches (5.1 cm) (outside diameter) steel tubing or pipe, or if other structural metals are used, they must be designed to carry an equivalent load. The size of bearers (outside diameter) and the spacing of posts must meet the requirements contained in ANSI A10.8.

(b)  Limit tube and coupler scaffolds to heights and working levels according to ANSI A10.8.  Drawings and specifications for tube and coupler scaffolds that exceed the limitations in ANSI A10.8 must be designed by an RPE.

(c)  Construct all tube and coupler scaffolds to support four times the maximum intended loads according to ANSI A10.8 or as specified by an RPE (with knowledge in structural design).

(d)  Erect runners along the length of the scaffold so they are located on both the inside and the outside posts at even heights.

(d-1)  When tube and coupler guardrails and midrails are used on outside posts, they may be used in lieu of outside runners.  If guardrail systems are removed to other levels, install extra runners to compensate.

(d-2)  Interlock runners to form continuous lengths and couple them to each post.

(d-3)  Install the bottom runners as close to the base as possible.

(d-4)  Place runners not more than 6 feet - 6 inches (2 m) on center.

(e)  Bearers.

(e-1)  Install bearers transversely between posts.

(e-2)  When coupled to the post, bear the inboard coupler directly on the runner coupler.  When coupled to the runners, keep the couplers as close to the post as possible.

(e-3)  Extend bearers beyond the posts and runners and to provide full contact with the coupler.

(f)  Install bracing across the width of the scaffold at the ends of the scaffold at least every fourth level vertically and repeated every third set of posts horizontally.

(f-1)  Extend such bracing diagonally from the outer post or runner at this level upward to the inner post or runner at the next level.

(f-2)  Install building ties adjacent to bracing.

(g)  Install longitudinal diagonal bracing across the inner and outer rows of poles at approximately a 45-degree angle in both directions from the base of the end post upward to the extreme top of the scaffold.

(g-1)  Where the longitudinal length of the scaffold permits, repeat such bracing beginning at every fifth post.

(g-2)  On scaffolds where the length is shorter than the height, extend the longitudinal bracing diagonally from the base of the end posts upward to the opposite end posts and then in alternating directions until reaching the top of the scaffold.

(g-3)  Where conditions preclude the attachment of bracing to the posts, it may be attached to the runners.

(3)  Fabricated Frame Scaffolds (Tubular Welded Frame Scaffolds) (see 29 CFR 1926.452).

(a)  Space tubular welded panels or frames consistent with the loads imposed.

(b)  Properly brace scaffolds by cross, horizontal, or diagonal braces (or combination of these) to secure vertical members together laterally. The cross braces must be of such length as will automatically square and align vertical members so that the erected scaffold is always plumb, square, and rigid.  Secure all brace connections.

(c)  Set scaffold legs on adjustable bases or plain bases placed on mudsills or other foundations adequate to support the maximum rated loads.

(d)  Place frames one on top the other with coupling or stacking pins to provide vertical alignment of the legs.

(e)  Where uplift may occur, lock panels together vertically by pins or other equivalent suitable means.

(f)  Drawings and specifications for all frame scaffolds over 125 feet (38.1 m) in height above the base plates must be designed by an RPE.

(4)  Manually Propelled Mobile Scaffolds, including mobile work stands, such as “baker scaffolds.”

(a) All wheels and casters on rolling scaffolds must have a positive locking device, securely fastened to the scaffold, to prevent accidental movement.

(b)  Lock all casters or wheels when a scaffold is occupied.

(c) Apply the force necessary to move the mobile scaffold as close to the base as practical and make provision to stabilize the tower during movement from one location to another.

(d)  Use rolling scaffolds only on firm, level, and clean surfaces.

(e)  Free-standing mobile scaffold working platform heights must not exceed three times the smallest base dimension.

(f)  Do not permit persons to ride on manually propelled scaffolds unless all of the following conditions exist:

(f-1) The ground surface is within 3 degrees of level and free from pits, holes, or obstructions.

(f-2) The minimum dimension of the scaffold base (when ready for rolling) is at least one-half of the height and outriggers, if used, are installed on both sides of staging.

(f-3) The wheels are equipped with rubber or similar resilient tires.

(f-4) All tools and materials are secured or removed from the platform before the scaffold is moved.

Note.  Follow all manufacturer’s recommendations for use of outriggers.

e.  Wood Pole Scaffolds (see 29 CFR 1926.452).  (22-8.e)

f.  Suspended Scaffolds.  See 29 CFR 1926.452 for single-point adjustable suspension scaffolds and for two-point adjustable suspension scaffolds.  (22-8.f)

(1)  Suspended scaffolds must be designed, constructed, operated, inspected, tested, and maintained according to the operating manual for the device.

(2) All parts of all suspended scaffolds must have a minimum safety factor of four. A minimum safety factor of six is required for support ropes.

(3)  Support Ropes.

(a)  Attach support ropes at the vertical centerline of the outrigger so that the attachment will be directly over the hoist machine.

(b)  Support ropes must be vertical for their entire length.  Do not sway the scaffold nor fix the support ropes to any intermediate points to change the original path of travel.

(c)  Equip the fixed end of the support rope with a proper size thimble and secure it by eye splicing or equivalent means.  Braze or secure free ends to prevent fraying.

(d)  For traction hoists, the support rope must be of such length that the operator can descend to the lowest point of travel without the end of the wire rope entering the hoist.  Where the wire rope is inadequate for the lowest descent, make provision to prevent the hoist from running off the wire rope.

(e)  For winding drum type hoists, running ends of suspension ropes must be attached by positive means to the hoisting drum so that at least four wraps of the rope will remain on the drum at all times.

(f)  Support ropes must be capable of resisting chemicals or conditions to which they are exposed.

(g)  Do not weld, burn, rivet, or perform open flame work on any platform suspended by fiber or synthetic rope.

(h)  Do not use defective or damaged rope as lifelines or suspension lines. The repairing of wire rope is prohibited.

(4) All suspension scaffold support devices such as outrigger beams, cornice hooks, parapet clamps, or similar devices must meet the following:

(a)  Be made of mild steel, wrought iron, or materials of equivalent strength.

(b)  Be supported by bearing blocks.

(c)  Rest on surfaces capable of supporting the reaction forces imposed by the scaffold hoist operating at its maximum rated load.

(d)  Be secured against movement by tiebacks installed at right angles to the face of the building whenever possible and secured to a structurally sound portion of the building. Tiebacks must be equivalent in strength to the hoisting rope.

(5)  Outrigger Beams.

(a)  Outrigger beams must be made of structural metal and be restrained to prevent movement.

(b)  Stabilize the inboard ends of outrigger beams by bolts or other direct connections to the floor or roof deck, or by counterweights.  Do not use counterweights to stabilize mason's multiple point adjustable suspension scaffold outrigger beams.

(c)  Mason's multiple point adjustable suspension scaffold connections must be designed by an RPE experienced in scaffold design.

(d)  Counterweights must be made of non-flowable solid material secured to the outrigger beams by mechanical means.  Do not remove until the scaffold is disassembled.

(e)  Secure outrigger beams by tiebacks equivalent in strength to the suspension ropes. Secure the tiebacks to a structurally sound portion of the building or structure so that they are installed parallel to the centerline of the beam.

(f)  Outrigger beams must be provided with stop bolts or shackles at both ends.

(g)  When channel iron beams are used in place of I-beams, securely fasten the
        channels together with the flanges turned outward.

(h)  Install outrigger beams so that all bearing supports are perpendicular to the beam centerline.

(i)  Set and maintain outrigger beams with the web in a vertical position.

(j)  Where a single outrigger beam is used, place the steel shackle or clevises with which the wire ropes are attached to the beam directly over the hoisting machines.

(6)  Hoisting Machines.

(a)  Hoisting machines must be of a type tested and listed by a NRTL.

(b)  Each hoist must contain a name plate(s) containing the following:

(b-1)  Manufacturer's name.

(b-2)  Maximum load rating.

(b-3)  Identification number.

(b-4)  Wire rope specifications.

(d) All powered hoists must be equipped with speed reducers and a primary brake and a secondary brake.

(d-1) The primary brake must automatically engage whenever power is interrupted or whenever the operator ceases to apply effort.

(d-2) The secondary brake must stop and hold the hoist under over speed or abnormal conditions. All secondary brakes must be periodically tested under simulated conditions according to the manufacturer's instructions.

(e)  Each powered hoist must have its own separate control.

(e-1)  If the control is of the push-button type, it must be constant pressure.

(e-2)  If the control is of the fixed-position type, it must have provision for automatic locking when in the off position or be guarded against accidental actuation.

(e-3)  If the control is of the lever type, it may be of the constant pressure type or of the fixed-position type.

(f)  Manual operation of powered hoists may be provided if the hoist is designed so that not more than one person per hoist is required to perform this operation.

(f-1)  During manual operation, a means must be provided to make the prime mover inoperative.

(f-2)  Provide instruction advising personnel to disconnect the power source before using a manual crank.

(g)  Manually Operated Hoists.

(g-1)  Provide a means to prevent rapid handle movement or fast un-spooling during manual operation.  Do not place mechanisms used to allow fast un-spooling during the erection process on the scaffold.

(g-2)  In the event a controlled descent device is used, it must not bypass the secondary brake.

(g-3) All winding drum hoists must be provided with a driving pawl and a locking pawl that automatically engages when the driving pawl is released.

(g-4)  Gripping-type hoists must be designed so that the hoist is engaged on the suspension rope at all times, including all travel actuations of the operating lever.

(g-5)  Each winding drum hoist must be provided with a positive means of attachment of the suspension hoist. The drum attachment must develop a minimum of four times the rated capacity of the hoist.

(g-6)  Each hoist must require a positive crank force to descend.

(7)  Working Surfaces on Suspended Scaffolds.

(a)  Light metal platforms, when used, must be of a type tested and listed by an NRTL.

(b)  Ladder-type platforms are prohibited.

(c-1)  Planking must be composed of not less than nominal 2 inches x 10 inches (5.1 cm x 25.4 cm) unspliced planks, cleated together on the underside, starting
            6 inches (15.2 cm) from each end at intervals not to exceed 4 feet (1.2 m).

(c-2)  Do not extend the planking beyond the hangers more than 12 inches
            (30.5 cm). Securely fasten a bar or other effective means to the platform at each end to prevent its slipping off the hanger.

(c-3) The span between hangers for planked platforms must not exceed 8 feet
            (2.4 m).

(d)  Beam platforms are prohibited.

(8)  Guy, brace, guide, or equip suspended scaffolds with a tag line to prevent swaying.

(9) Two-Point Suspension Scaffolds.

(a) Two-point suspension scaffold platforms must not be less than 20 inches (50.8 cm) or more than 36 inches (91.4 cm) wide.  Securely fasten the platform to the hangers by U-bolts or by other equivalent means.

(b)  The hangers of two-point suspension scaffolds must be made of mild steel, or equivalent materials, having a cross sectional area capable of sustaining four times the maximum rated load and must be designed with a support for a standard railing.

(d) The platform on every two-point suspension scaffold must be of the light metal or planking.

(e)  Do not joint two-point suspension scaffolds by bridging.

(f) Two-point suspension scaffold platforms, when in use, must be level within 1 inch (2.5 cm) for every 1 foot (0.3 m) of platform length.

(10)  Mason's Multiple-Point Adjustable Suspension Scaffolds.

(a)  When employees on the scaffold are exposed to overhead hazards, provide overhead protection equivalent in strength to 2 inches (5.1 cm) planking on the scaffold not more than 9 feet (2.7 m) above the platform. The overhead protection must be laid tight and extend the entire width of the scaffold.

(b) The scaffold must be capable of sustaining a load of 50 lb/ft2 (1.1 kg/m2).  Do not overload.

(11)  Stonesetters' multiple-point adjustable suspension scaffolds must be designed and used according to ANSI A10.8.

(12)  Working Capacities.

(a)  On suspension scaffolds designed for a working load of 500 lb. (226.8 kg), do not permit more than two people to work at one time.

(b)  On suspension scaffolds with a working load of 750 lb. (340.2 kg), do not permit more than three people to work at one time.