Presentation on theme: "Scaffolds These handouts and documents with attachments are not final, complete, or definitive instruments. This information is for guidance purposes."— Presentation transcript:
1ScaffoldsThese handouts and documents with attachments are not final, complete, or definitive instruments. This information is for guidance purposes only. You should independently verify and satisfy yourself as to its accuracy. The AHBSIF does not assume any liability for damages arising from the use of this information or exhibits and attachments thereto and renders no opinion that any of the terms, conditions, and/or cited federal standards in this document and the exhibits and attachments should be explicitly followed by the fund member. Seek specific guidance from the appropriate regulator (OSHA) or professional advisor.
2Introduction to Scaffolds OSHA revised the scaffold standard in 1997 due to the following;A quarter of the workers responsible for installing work platforms and inspecting, and assembling them had no formal training.Only 1/3 of scaffolds were equipped with handrails.
3Defining a Competent Person One who is capable of identifying existing and predictable hazards in the surroundings, or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to eliminate them.Scaffolds shall be constructed, altered, or dismantled under the supervision of a competent person.
4General Requirements All scaffolds must be inspected prior to use. 10’ is the point at which some means of fall protection must be used.Top handrails should be around 42”, with the mid-rail about half way at 21”.Toe boards or other adequate means of falling object protection must be installed if there is a possibility of anything falling and striking someone below.
5General RequirementsAll scaffolds must support their own weight and 4x the maximum intended load.Vertical tie-in or outrigger support is not necessary on a free-standing scaffold until the height exceeds the minimum dimension of the base by four times.
6General Requirements Ladder use on a scaffold is prohibited. Platforms must be kept clear of debris.Do not load side brackets. Most are rated at 25 lbs/ft² maximum.
7Decks And Planking All platforms must be fully decked or planked. Each abutted end of a plank shall rest on a separate support surface.Overlap platforms not less than 12” only over supports, unless restrained to prevent movement, i.e. ”Cleating”.The working deck should never be more than 14” away from the working surface.
8Decks And PlankingA scaffold grade plank will be stamped or marked as suchPlank must be laminated or solid drawnA lumber yard 2 x 10 can be used if it is free of knots or other defectsRough Sawn, Full Dimension LumberNominal Thickness LumberWorking Load in lbs/ft²255075Permissible Span in Feet1086
910’ + 1/2” for every additional kV Overhead Power LinesThe clearance between scaffolds and power lines is as follows:Insulated LinesMinimum Distance< 300 V3’300 to 50 kV10’> 50 kV10’ + 1/2” for every additional kVUninsulated Lines< 50 kV
10Frame ScaffoldsSystems should use only original parts. Components from different systems should not be mixed.All frame scaffolds must use a manufactured base pad. Vertical tubes should never sit directly on the ground or make-shift mud sill.X-braces may serve as a top-rail or mid-rail, but not both.If aluminum walking decks are used, be sure that end hooks are in place and that the dimensions match the scaffold.
11Frame Scaffolds - Access OK for ClimbingMust have External AccessLadder FrameWalk-Through
12Frame Scaffolds - Access Erectors can climb either type, but provisions for safe access should be established as soon as possible.Bottom rung cannot be more than two feet high.Options for access are manufactured bolt-on ladder system, stair system, or extension ladder secured and sloped properly.X-braces are not intended for use as access.
13“Stick-Built” Pole Scaffold 2” x 4” poles free of knots, splits or other defects.1” x 4” cross-bracing for each section.2” x 6” or 2” x 8” block under pole if soft ground.Walk board a minimum 2” x 10” free of knots or other defects.Walk boards must hang over bearer a minimum of 6”.Walk boards must overlap each other a minimum of 12”.2” x 4” top rail, mid rail, and toe board
14Stick Built Scaffolds Proper overlap on deck planking Top rail and mid rail established after deck height reaches ten feetAdequate support between stanchionsProper mud sills under polesIs this scaffold complete?
15Pump Jack ScaffoldsPump Jack brackets, braces, and accessories must be fabricated from metal.Each pump jack bracket must have two positive gripping mechanisms.Poles should be secured to the structure with triangular bracing.Work benches should not be used as a working deck.If 2x4’s are spliced to make a pole, mending plates must be installed to maintain strength.
16Ladder Jack Scaffolds Platforms must not exceed 20’ in height. Job made ladders cannot be used to support ladder jack scaffolds.Ladders that support ladder jacks must be placed, fastened, or equipped with devices to prevent slipping.Scaffold platforms must not be bridged to one another.Werner and Louisville produce handrail systems for ladder jack working decks.
17Trestle Ladder Scaffold Scaffold platforms must be placed no higher than the second-highest rung of the ladderA conventional step ladder is not to be used for this scaffold configurationWork platforms must be secureAll general scaffold and ladder standards apply
18Carpenters Bracket Scaffold Typically constructed of woodEach piece must be properly fitted and securely joinedBrackets must be no more than 8 ft. apartThe platform can be no less than two 2’ x 10’ size planksAttachment must occur in one of following ways:Hook over a well secured and strong supporting memberA bolt of no less than 5/8” diameter extended through the inside of the building wallUnit attaches via metal stud or welding if possible
19Hanging Scaffold System The Wall WalkerDevice meets OSHA standardsIt can be hung on the inside or outside of the wallFall protection attachments are availableThe horizontal beam positional is adjustable
20The Wall Walker General Framing, exterior face hanging on top plate Handrail System in placeSetting pre-fab trussesAluminum walk deck locked into place
21The Wall Walker Cutting tails on rafters Using inside wall position from top plateEasy stow and carryUnit folds down, handrail post stores inside vertical support
22Wall Walker Hardware Mid Wall Bracket Hand Rail Brackets Stabilizer Bar
23Manually Propelled Mobile Scaffolds Also known as a “Perry” or “Baker” scaffold.The casters and wheels must be locked to prevent movement while the scaffold is stationary.An employee may ride this scaffold under the following conditions:The floor is level and free of all obstructionsThe minimum dimension of the scaffold base is at least half the heightThe wheels are equipped with rubber or some other resilient materialAll tools and materials are secured or removed prior to movementBecause the wheels and castors must be locked once the scaffold is set, this prohibits movement from being a one-man operation.
24Rustgo Manual Work Platform All-terrain motorless work platform with rear steering capabilitiesCan be towed to jobsite location on a standard hitchWinch system on each upright raises and lowers work platformFront handrail system is completely removableEmployees cannot stay on work platform during movementAll general scaffold standards apply
25Horse ScaffoldsMembersDimensionsHorizontal Bearer3 x 4”Legs11/4” x 41/2”Braces between Legs1 x 6”Gusset Brace at top of Legs1 x 8”Half Diagonal Braces11/4 x 41/2”Horses must be spaced not more than 5 ft. for medium duty, not more than 8 ft. for light dutyFor stacking applications, must not exceed two tiers or ten feet in heightHorses must be inspected for defects prior to useAll general scaffold standards apply
26Adjustable Scaffolds Use is more common to commercial projects Pre-shift inspection of all components is criticalHoist MotorsOutriggersAll Fastening PointsAll general scaffold standards apply
27Crawling Boards / Chicken Ladders Crawling board must be at least 10” wide and 1” thickCleatsMust be at least 1” x 11/2”Must be as long as the board is wideMust be spaced equally at no more than 2’ apartIf the crawling board presents a fall exposure, fall protection must be used i.e. handrails-harness
28Scissor LiftsScissor lifts are not addressed by the aerial lift provisions of Subpart L.There are no OSHA provisions that address scissor lifts, however, employers must comply with the applicable provisions of Subpart L, both general and specific.Example:Scissor lifts are mobile, the specific requirements for mobile scaffolds standard (§ (w) - mobile scaffolds) shall be used.Scissor lifts do not require a personal fall arrest system for occupants.
29Aerial LiftsOccupants of an aerial lift must use a personal fall arrest system.Occupants are required to stay on the floor of the basket at all times.Pre-shift inspection is critical to insure safe operation.The lift may not be field modified without the manufacturers consent.
30Scaffold ChecklistStability of the ground or work surface, proper mud sills when neededAll components from the same manufacturerAdjustable screw jacks with base pads in every postExternal ladder access for steel scaffold bucks not designed for climbingErection, dismantle, alteration done under supervision of a competent personComplete decking from front to back on all working levelsFall protection in place once work deck reaches or exceeds 10 ft. for conventional scaffoldsDaily inspection performed by a competent person before and during the shiftScaffold must be designed to hold four times the intended working load (safety factor of “4”)Tie-ins set once the height of the scaffold exceeds four times the minimum base dimensionScaffold grade planking or better for all work surfacesPlanks overlapped over horizontal support no less than 12”Overhead protection for other trades or personnel belowPre-shift inspection of all motorized components, proper PPE in use