TITLE:	ES&H Manual
DOCUMENT ID:	6132 Appendix T3 Scaffold Guidelines

What is a Scaffold?

A temporary elevated or suspended work unit and its supporting structure used for supporting worker(s), materials, or both.

Types of Scaffolds:

· Fabricated tubular frame scaffolds*	· Form and carpenter bracket scaffolds
· Manually propelled mobile scaffolds*	· Interior hung scaffolds
· Suspended scaffolds	· Window jack scaffolds
· Tube and coupler scaffolds	· Pump jack scaffolds
· System scaffolds	· Horse scaffolds
· Bricklayer’s square scaffolds	· Outrigger scaffold

* These two are most commonly used at Jefferson Lab and are discussed in this appendix.

What are the sources for criteria on scaffold design, erection, and use?

Standards:

· OSHA Construction Standard 29 CFR 1926, Subpart L Scaffolds

· OSHA General Industry Standard 29 1910.28, Safety Requirements for Scaffolding

· Jefferson Lab ES&H Manual Chapter 6132 Ladders and Scaffolds

References:

· ANSI A10.8-1988, Scaffolding Safety Requirement

Terminology

design load The maximum intended load, the total of all loads, including the worker(s), material, and the equipment placed on the unit.

fabricated scaffold deck A work unit equipped with end hooks that engage the scaffold bearer.

guardrail system A rail system erected along the open sides and ends of the platforms, consisting of a top rail, mid rail, and supports.

load ratings (uniformly distributed load)

· Heavy duty: max. working load of 75 lbs. /ft2

· Medium duty: max. working load 50 lbs/ft2

· Light duty: max. load of 25 lbs/ft2

qualified (or competent) A term describing one who, by possession of a recognized degree, certificate, or professional standing, or who by extensive knowledge, training, and experience has successfully demonstrated the ability to solve or resolve problems relating to the subject matter, the work, or the project. In this situation, someone who has familiarity and experience with the scaffold system and its proper erection and use.

platform (or stage) An elevated work surface composed of one or more platform units.

platform unit Individual wood planks, fabricated decks, and fabricated platforms.

prefabricated mobile scaffold A mobile scaffold system that is manufactured and shipped with all necessary components, with the sole purpose of being used as a mobile scaffold.

scaffold access A separate, attachable, or built-in means of access to and from a scaffold work unit.

scaffold plank A board of sawn lumber or laminated wood, marked “Scaffold Grade.”

tested design Load tested to demonstrate that it can support the required load including any appropriate safety factor.

Tie device used between scaffold components and the building to enhance lateral stability.

Toeboard A barrier secured along the sides and ends of a platform unit to guard against the falling of material, tools, and other loose objects and to prevent feet from slipping off the platform.

Scaffold Erection

• Footing must be sound, rigid, and capable of supporting the weight of the maximum intended load.
• Unstable (or crushable) objects such as barrels, boxes, loose brick or concrete block may not be used to support the scaffold or planks.
• Lumber is OK for base support, but it must be sufficiently wide for stability. The best choice is to use screw-jack levelers for the base.
• Rolling scaffolds may only be used on level, firm surfaces. The brakes must work, and be used whenever scaffold is in place.
• Free-standing scaffolds with a height-to-base ratio > 4:1* need tipping restraints (wall ties).
• vertical ties at the 4:1 elevation point and every 26 ft thereafter
• longitudinal ties at each end and at 30-foot intervals

Some Other Considerations for Scaffold Erection:

• Scaffold frames must be square and plumb.
• Cross braces are used at every frame pair. Make sure they’re locked in place.
• If uplift is possible, panels must be secured by pins or other equivalent means.
• Don’t mix different manufacturers’ components unless they fit correctly and provide structural integrity.
• Makes sure the system is adequate for the intended load. Check the labels or call the manufacturer or rental company.
• Stay 10+ feet away from power lines.
• All scaffold system components must support 4 times the maximum intended load.
• All fabricated tubular frame scaffolds must be erected under the supervision of a qualified (or competent) person. Consider what this means for your particular job. In most case
• Where conventional scaffolding configurations are needed, this means the qualified person:
• explains what needs to be done,
• ensures the correct scaffold system is used,
• monitors its erection, and
• inspects it before initial use and daily thereafter.

Guardrails

Guardrails are required on all open sides and ends of platforms more than 10 feet high and any scaffold if a side is less than 45 inches. Exceptions:

· Scaffolds that cover the entire interior of the building or room: wall-to-wall.

· On sides or ends with < 16 inches gap to the building wall.

During scaffold erection and dismantling use safety harnesses and lifelines. Do not attach lifelines to the scaffold. Use another secure attachment point.

Top rails must be within 38 to 45 inches above the platform and supported at least every 10 feet.

Guardrail Materials:

· Steel tubing, 1 inch diameter x 0.070-inch wall

· Lumber, 2 x 4 inches

· Structural steel angle, 1 1/4 x 1 1/4 x 1/8 inches

· Aluminum tubing, 1.990 inch diameter x 0.058-inch wall

· Other materials capable of withstanding a 200 lb force in any direction except upwards.

Cross bracing is acceptable for a mid rail if it is at least 20 inches and no more than 30 inches above the platform.

Cross bracing is acceptable as a complete guardrail system if the crossing point is between 31 and 48 inches above the platform and the ends are no more than 54 inches apart.

Non-scaffold fall protection requirements for construction activities begin at elevations of six feet or more or whenever a person works above dangerous machinery or operations. This can be guardrails, fall-arrest systems, special warning systems, or work-controls.

In non-construction settings, guardrails are required whenever there is a drop of more than four feet.

Toeboards and screens

· Toe boards are primarily intended to be a barrier to prevent tools or materials from being knocked off the scaffold.

· Made of 2 x 4 inch lumber or the equivalent. They must extend at least 3 1/2 inches above the platform and have a snug fit to the platform along their length.

· If material is stacked higher than the toeboards, or if people work or pass beneath the scaffold, a screen is required between the top rail and toeboard. (Mid rails may be omitted if a screen is used.)

· Screens should be made of 18 gage, 1/2 inch wire mesh or equivalent.

Planking

· Platforms must be completely planked with platform units.

o No gaps > 1 inch except where scaffold uprights interfere and as necessary for an entrance opening.

o Sawn lumber must be stamped “scaffold plank grade” selected for the working load, or must be selected by the qualified person to meet the intended load requirements.

o Fabricated scaffold decks must be labeled for working load and used accordingly.

o Lumber used for scaffold platforms may not be painted (this conceals knots and other defects.).

People are usually the main load, but be alert to tasks that require people to lift upwards, increasing the load.

· If planking must overlap end-to-end, and it is not secured, a minimum of 12 inches overlap is needed. The overlap must be centered over an intermediate support.

· At end supports, planks must have an overhang of 6 to 12 inches unless cleats or hooks are used to prevent planks from sliding. Never exceed 12 inches of overhang.

Fabricated scaffold decks (with end hooks) are usually easier to install and stay positioned much easier than does planking.

Scaffold Access

Options for access ladders:

· Conventional straight ladders, Type I or IA, secured to the scaffold, extending 3 feet past the platform.

· Hook-on ladders made for this purpose

· Stair assemblies made for the scaffold system

· The scaffold frame itself if:

o maximum rung spacing no more than 16 3/4 inches

o rung width at least 12 inches

Miscellaneous Considerations

· Don’t use ladders or makeshift devices to get extra working height on a scaffold.

· Don’t use damaged scaffold components: platform units, frames, crossbars, rails. What’s “damaged?” Ask the qualified/competent person.

· If moving vehicles are present, the scaffold needs to be marked conspicuously with ropes or barricades.

Special Considerations for manually propelled mobile (rolling) scaffolds

· Usually comes as a package. Use all the pieces!

· May use different bracing configurations than tubular frame scaffolds. Read the directions! Instructions must be on a label or supplied as a separate document. This is the responsibility of the supplier.

· Casters must roll and swivel freely, have working brakes, and must not be able to fall out of the leg.

· Casters must be locked except during intentional moving.

· People who erect and use mobile scaffolds must be trained.

Moving a Rolling Scaffold

· Apply force as close to the base as possible.

· Remove or secure materials on the platform. Small tools can be left if the toeboard prevents their falling.

· If people are on the platform, make sure they’re prepared.

· Don’t move an occupied rolling scaffold if height-to-base ratio is > 2:1. (Outriggers can be used to widen the base if they contact the floor.)

· No pits, holes, or obstructions on the floor. Even a small object can cause a caster to stop abruptly.

· Re-lock the casters immediately after the move.

Table 1 Tubular Frame Scaffolds Inspection Checklist

Project	Date of Inspection:
Group/Contractor:
	Yes	No	N/A	Action/Comments
1. Are scaffolds components and planking in safe condition for use and is plank graded for scaffold use?
2. Is the frame spacing and section size capable of carrying intended loadings?
3. Have qualified persons been in charge of erection?
4. Are sections properly placed and adequate size?
5. Have screw jacks been used if needed to level and plumb scaffold instead of unstable objects such as concrete blocks, loose bricks, etc.?
6. Are base plates and/or screw jacks in firm contact with sills and frame?
7. Is scaffold level and plumb?
8. Are all Scaffold Legs braced and braces properly attached?
9. Are guard railings in place on all open sides and ends?
10. Has proper access been provided?
11. Has overhead protection or wire screening been provided where necessary?
12. Has scaffold been tied to structure at least every 30’ in length and 26’ in height?
13. Have brackets and accessories been properly placed?
14. Is scaffold f ree of makeshift devices or ladders to increase height?
15. Are working level platforms fully planked between guardrails?
16. Does plank have 6” to 12” overlap beyond supports?
17. Are toeboards installed properly?
18. Have the following hazardous conditions been assessed?
a. power lines?
b. wind loading?
c. possible washout of footings?
d. Uplift and overturning moments due to placement of brackets, putlogs, or other causes?
19. Have personnel been instructed in the safe use of the equipment?
Qualified Person’s Signature:

Table 2: Rolling Tower Inspection Checklist

Project	Date of Inspection:
User:
	Yes	No	N/A	Action/Comments
1. Are scaffold components and planking in safe condition for use?
2. Have competent persons been in charge of erection?
3. Is tower level and plumb?
4. Is tower height less than 4 times the minimum base width?
5. Are casters of proper size with effective locking devices?
6. Are screw jacks extended less than 12”?
7. Do casters roll freely and lock securely?
8. Are casters and all frames locked together?
9. Is tower fully braced on both sides?
10. Has horizontal diagonal bracing been positioned properly at the base and intermediate levels of 20”?
11. Has proper guard railing been provided?
12. Have stair-units or ladders and guard rail gates been provided?
13. Is platform fully planked and are toeboards provided when necessary?
14. Are planks secured to prevent displacement or uplift?
15. Have personnel been instructed in the safe use of the equipment?
Qualified Person’s Signature:

ISSUING AUTHORITY	APPENDIX AUTHOR	APPROVAL DATE	EFFECTIVE DATE	EXPIRATION DATE	REV.
ESH&Q Division	Ned Walker	06/01/01	06/01/01	06/01/04	0

This document is controlled as an on line file. It may be printed but the print copy is not a controlled document. It is the user’s responsibility to ensure that the document is the same revision as the current on line file. This copy was printed on 8/14/2009.