Scaffolds and scaffolding work guidance material

Scaffolding Good Practices

A vast number of those in the construction industry use scaffolding on a daily basis. According to OSHA, nearly 65 percent of workers in the construction industry work on scaffolds frequently. From steel erectors to building equipment installers, bricklayers, window washers, carpenters, and painters, just to name a few, nearly 2.3 million construction workers frequently work on scaffolds.

Construction sites are inherently unstable environments, with movement of workers, materials, etc. and changing landscapes. In 2004, approximately 400,000 workers suffered construction-site injuries. The Bureau of Labor Statistics revealed in 1996 that 25 percent of workers injured in scaffold accidents had received no scaffold training. With the high potential for serious injury, construction safety education remains a top priority.

About Scaffolding
A scaffold is defined as an elevated, temporary work platform. The three basic types of scaffolds are:
• Supported scaffolds, which consist of one or more platforms supported by rigid, load-bearing members, such as poles, legs, frames, outriggers, etc. Common types of supported scaffolds are frame, system, mobile (rolling), etc.
• Suspended scaffolds, which are one or more platforms suspended by ropes or other non-rigid, overhead support. Suspended scaffolds are often used when washing windows or to access bridges and other structures when overhead support is the best option.
• Other scaffolds, principally man lifts, cherry pickers, scissor lifts, etc., are sometimes thought of as vehicles or machinery but can be regarded as another type of supported scaffold.

Preventing Scaffolding Accidents
The most important preventative measures are training and education, proper selection of equipment, and proper use of equipment. Education is the most powerful tool in reducing the number and severity of scaffold-related injuries. Following are some basic guidelines for workers who use scaffolds

When using supported scaffolds:
• Prior to use, inspect the scaffold to ensure it has not been altered and is in safe working condition.
• Erected scaffolds and platforms should be inspected continuously by those using them.
• Exercise caution when entering or leaving a work platform.
• Do not overload scaffolds. Follow manufacturer's safe working load recommendations.
• Do not jump onto planks or platforms.
• Do not use ladders or makeshift devices to increase the working height of a scaffold. Do not plank guardrails to increase the height of a scaffold.
• Climb in access areas only, and use both hands.
• Where required, use proper personal fall arrest equipment, and use it properly.

When using suspended scaffolds:
• Use all equipment and all devices in accordance with the manufacturer's instructions.
• Do not overload, modify, or substitute equipment.
• Before commencing work operations, preload wire rope and equipment with the maximum working load, then retighten wire rope clips and recheck rigging to manufacturer's recommendations.
• Inspect all rigging equipment and suspended scaffold systems daily.
• Inspect wire rope during each ascent or descent for damage.
• Use care to prevent damage to equipment by corrosive or other damaging substances.
• Clean and service equipment regularly.
• Always maintain at least four (4) wraps of wire rope on drum type hoists.
• Do not join platforms unless the installation was designed for that purpose.
• Move suspended scaffolds horizontally only when they are not occupied.
• When rigging for another drop, ensure sufficient wire rope is available before moving the suspended scaffold system horizontally.

OSHA estimates as many as 50 lives can be saved and 4,500 accidents prevented annually if construction sites are compliant with current safety standards.

The most common scaffold hazards are:
• falls from elevation;
• collapse/overturning of the scaffold;
• being struck by falling tools, work materials, or debris; and
• electrocution, principally due to proximity of the scaffold to overhead power lines.

Falls
In 2004, general falls, including falls from scaffolding, ladders, and other places, accounted for 36 percent of all construction-related fatalities. Proper selection, use, and installation of guardrails, personal fall arrest systems, and fall prevention systems is essential to prevent falls and to prevent deaths and serious injuries due to falls.

Select equipment that meets current standards. Install it properly as directed by the manufacturer. Use it as it is intended to be used. Again, education is the key. A properly selected personal fall arrest system that meets all current standards does no good if it is not used by employees.

Collapse/Overturning
Collapse of a scaffold is usually due to overloading, improper assembly, or faulty parts. Scaffolds are highly engineered products. They have been designed to support a specified load when erected in a specified configuration. Carefully follow the manufacturer's instructions regarding loading. Consider the weight of workers and materials, and consider buildings or structures that may be used to support the scaffold. Any part of a building or structure used to support the scaffold must be capable of supporting the maximum intended load.

Overturning or tipping of scaffolds occurs when they are not properly tied or guyed. Ties must be installed when the scaffold height (measured to the uppermost platform) exceeds four (4) times the smallest base dimension. Some state or local codes require ties at three (3) times the smallest base dimension. Cantilevered platforms used to bring material up to the work platform, such as side brackets and hoist arms, can cause overturning and may require the scaffold to be tied at lower heights. Adding an enclosure on a scaffold, even an open mesh, also can overturn a scaffold due to an increase in wind loading. Additional ties or guys will be required. Check with an engineer to determine the location and spacing of ties for enclosed scaffolds.

Proper assembly is essential. Proper assembly begins with a site survey. Before erecting a scaffold, a competent person should survey the site for hazards, such as untapped earth fills, ditches, debris, unguarded openings, and other hazardous conditions that may lead to instability. Scaffolds must be properly assembled with the scaffold base set on base plates and an adequate sill or pad to prevent slipping or sinking. Adjusting screws or other approved methods should be used to adjust to uneven grade conditions. Follow the manufacturer's recommendations regarding bracing and tying. Do not mix scaffold components manufactured by different manufacturers.

Do not remove a scaffold component without proper authorization. Deaths have occurred from unauthorized removal of scaffold components, which may lead to instability or non-functioning safety equipment. For example, a worker on a later shift will not know that a guardrail or brace has been removed for better access to a particular activity. And do not alter scaffold components or use them for purposes for which they were not designed.

To prevent overturning or collapse of rolling scaffolds, do not ride the scaffold. Wheels or casters must be locked to prevent caster rotation and scaffold movement when the scaffold is in use, and the top platform height as measured from the rolling surface of a rolling scaffold must not exceed four (4) times the smallest base dimension.

The first step in preventing collapse of a scaffold is proper selection. Use scaffolds that have been tested to the ANSI/SSFI SC 100 standard for testing and rating of scaffolds. This standard was developed by the members of the Scaffolding, Shoring, and Forming Institute (SSFI) to provide a means of evaluating scaffolds and components. For suspended scaffolds, make sure that the hoist complies with ANSI/UL 1323 and has been tested and listed by a national lab, such as UL or ETL. Rigging devices, such as parapet clamps, cornice hooks, and outrigger beams, should be tested to the ANSI/SSFI SPS 1.1 standard.

Falling Material and Electrocution
To avoid injuries caused by falling tools, work materials, or debris, equip scaffolds with toeboards or equivalent devices as required by code. According to the ANSI/ASSE A10.8 standard, "Toeboards shall be required with guardrail systems on all open sides and ends of scaffolds at locations where persons are required to work or pass under the scaffold."

In addition, the A10.8 standard states: "When materials are piled higher than the toeboard and in areas where persons are required to work or pass under the scaffolds, the scaffolds shall be provided with a safety screen or the equivalent of sufficient strength to prevent falling object hazards and located between the toeboard and the toprail extending along the entire opening." Secure or remove all materials from rolling scaffolds before moving the scaffolds.

Scaffolds should never be used or erected near electrical power lines without consulting a knowledgeable qualified person. Take care when using power tools or temporary electrical wiring, and obtain proper training before engaging in such activity.

Scaffold accidents and injuries aren't inevitable, but instead are preventable. Training, education, and proper selection and use of equipment will greatly reduce scaffold accidents. Use resources such as SSFI to learn about standards for scaffolds and tips on proper selection and use of equipment.

Use of Portable Grinders

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• Guards must be provided and adjusted properly to protect you. Replace damaged guards because if an abrasive wheel breaks while rotating, it can cause a serious injury.
• Before use, check the manufacturer’s stated running speeds, or markings on the grinder, and grinder wheel for the maximum speed that it can be used.
• Follow manufacturer’s manual for the safe use of grinder wheel guards.
• Clean and service grinders according to manufacturers' recommendations. Record all maintenance for grinders.
• Ensure that a machine will not operate when unattended by checking the dead-man (constant pressure) switch.
• Wear safety glasses or goggles, or a face shield (with safety glasses or goggles) to protect against flying particles. Gloves, aprons, metatarsal safety boots, and respiratory protection may be required, depending on the work.
• Ensure the floor around the work area is clean.
• Do not use wheels that are cracked or those that excessively vibrate.
• Do not operate grinder on wet floors.
• Use both hands when holding the grinder.
• Keep the power cord away from the grinding wheel and the material being ground.

When and how should you check the speed of the wheel?

• The maximum speed in revolutions per minute (rpm) is marked on every wheel. Never exceed this speed.
• Check that the wheel speed marked on the wheel is equal to or greater than the maximum speed of the grinder.
• Measure the speed of any new machine. Take several readings.
• Measure the speed of governor-controlled air-driven grinders after twenty hours of use or every week, whichever comes first. Measure the speed after any repairs.
• Measure the speed of electrically driven grinders monthly and after repairs.

What should you do when using portable grinders?

• Check that grinders do not vibrate or operate roughly.
• Hold grinders as follows:
  • Horizontal grinder - the full grinding face width of the wheel is in contact with the grinding surface.
  • Right-angle grinder - the grinding face of the wheel or disc is at an angle of between 5 and 15 degrees from the grinding surface.
  • Vertical grinder - the grinding wheel face is in contact with the surface.
• Use racks or hooks to store portable grinders.
• Stand away from the wheel when starting grinders. Warn co-workers to do the same.
• Inspect all wheels for cracks and defects before mounting.
• Ensure that the mounting flange surfaces are clean and flat.
• Ensure the wheel guard is in place while operating the grinder.
• Use the mounting blotters supplied.
• Run newly mounted wheels at operating speed for 1 minute before grinding.
• Wear appropriate eye, ear and face protection. Use other personal protective equipment or clothing, as required under the circumstances.
• Use an appropriate ventilation exhaust system to reduce inhalation of dusts, debris, and coolant mists. Exhaust systems must be designed and maintained appropriately.

Refer to Abrasive Wheels for further information.

What should you avoid when using portable grinders?

• Avoid using grinders near flammable materials.
• Do not clamp portable grinders in a vise for grinding hand-held work.
• Do not use any liquid coolants with portable grinders.
• Do not force wheels onto a grinder that is the wrong size or change mounting hole sizes.
• Do not tighten the mounting nut excessively.
• Do not put the grinder on the floor or working surface until the wheel has stopped turning.
• Do not keep any materials close to the grinding wheel when it is not in use.
• Do not wear loose clothing or dangling jewellery as they may get caught in the moving parts of the grinder. If you have long hair, keep it tied back.

Safe Working at Height

Why consider the risks of falls from height?

Falls from height are responsible for many serious and fatal injuries every year. If a person falls from a height above two meters the likelihood is that they will sustain serious injury.

Many work activities involve working at height. Working from ladders, scaffolds and platforms are obvious examples, but there are many more activities where people are required to work at height.

Examples include roof work, working over tanks and pits, at the edge of elevated structures, or on top of vehicles or trailers.

The risks of working at height

The main hazards associated with working at height are people falling and objects falling onto people below. These may occur as a result of inadequate edge protection, or from objects in storage being poorly secured.

Workers in maintenance and construction and many other people in a variety of jobs could be at risk of falling from height at work. Examples include: painters, decorators and window cleaners and those who undertake one-off jobs without proper training, planning or equipment.

Assessing risks from working at height

If work at height cannot be avoided, a risk assessment should be carried out before any work at height is undertaken. The assessment should highlight the measures that must be taken to ensure people are not at risk of falling from height.

The risks associated with working at height must be assessed. The Health and Safety Executive recommends a five-step approach to risk assessment, and the risk of slips, trips and falls should also be considered.

Step 1 Look for hazards associated with falls from height around the workplace. Where are people required to work at height? Do they carry out work from ladders, platforms, scaffolds, or unprotected or fragile roofs?

Step 2 Decide who might be harmed and how. Who comes into the workplace? Are they at risk? Are some groups more at risk than others?

Step 3 Consider the risks. Are there already measures in place to deal with the risks? Look at areas with unguarded openings or without guardrails and covers. Are regular inspections carried out?

Step 4 Record your findings if you have five or more employees.

Step 5 Regularly review the assessment. If any significant changes take place, make sure that precautions are still adequate to deal with the risks.

Over Head Crane Safety

Overhead Crane Safety, 29 CFR 1910.179

Quick Tips #107

Overhead cranes are used in many industries to move heavy and oversized objects that other material handling methods cannot. These cranes have a railed support structure, also known as a bridge, and a wheeled trolley that travels across the bridge horizontally. Several varieties of overhead cranes exist including gantry, semi-gantry, cantilever gantry, storage bridge and wall cranes.

OSHA regulates overhead crane safety through 29 CFR 1910.179, overhead and gantry cranes. This regulation covers general requirements, design, inspection, maintenance requirements and operations.

General Requirements

• All overhead cranes installed after August 31, 1971, must meet the specifications of the American National Standard Institute (ANSI) / American Society of Mechanical Engineers (ASME) Safety Code for Overhead and Gantry Cranes, ANSI B30.2
• Cranes can be modified and load capacity rerated as long as the modifications and associated structure is thoroughly checked for the new rated load by a qualified engineer or the equipment manufacturer
• The rated load of the crane shall be plainly marked on each side of the crane. If more than one hoist is present, each hoist will have its rating shown
• Clearance must be maintained above and to the side of cranes. Walkways cannot be placed in a crane operating zone that would compromise employee safety when the crane is in operation. Parallel cranes must have adequate clearance between the two bridges if no walls or structures are between them
• Only designated personnel will be permitted to operate a crane

Design Requirements

All overhead cranes are required to promote safe use. The OSHA overhead crane safety regulation specifies design requirements on the construction of the cab and its controls; foot-walks, ladders and stairways; bridge and trolley bumpers; hoist, holding, trolley and bridge brakes; electrical components; hoisting equipment; and warning devices.

Inspection Requirements

Due to the large and heavy objects often being transported by overhead cranes, routine inspections are necessary to ensure continued operation and overhead crane safety. An initial inspection of the crane prior to initial use of new and altered cranes is necessary. Once placed into service, overhead cranes will require two different types of inspections. Frequent inspections are done at daily to monthly intervals, while periodic inspections are completed at monthly to annual intervals. The purpose of the two inspection types is to examine critical components of the crane and to determine the extent of wear, deterioration or malfunction.

Initial Inspection – Prior to initial use

Items to be Inspected:

• Hoisting and lowering
• Trolley travel
• Bridge travel
• Limit switches, locking and safety devices
• Trip setting of hoist limit switches
• Load test of not more than 125% of rated load

Frequent Inspections

Items to be Inspected	Frequency
Operating mechanisms for maladjustment	Daily
Deterioration or leakage in pneumatic and hydraulic parts	Daily
Hooks with deformation or cracks (visual)	Daily
Hooks with deformation or cracks (written record with signature of inspector and date)	Monthly
Hoist chains and end connections for wear, twist or distortion (visual)	Daily
Hoist chains and end connections for wear, twist or distortion (written record with signature of inspector and date)	Monthly
Running Rope and end connections for wear, broken strands, etc. (written record with signature of inspector, rope identity and date)	Monthly
Functional operating mechanisms for excessive wear	As needed
Rope reeving according to manufacturers' recommendations	As recommended

Periodic Inspections

Items to be inspected:

• Deformed, cracked or corroded members
• Loose bolts or rivets
• Cracked or worn sheaves and drums
• Worn, cracked or distorted parts, such as pins, bearings, gears, rollers, etc.
• Excessive wear on brake-system parts
• Inaccuracies in load, wind and other indicators
• Electric or fossil fuel motors
• Excessive wear of chain drive sprockets and chain
• Deteriorated electrical components, such as pushbuttons, limit switches or contactors

Maintenance Requirements

A preventive maintenance program based on the crane manufacturer's recommendations must be implemented. If any deteriorated components or unsafe conditions are detected during the required inspections, they must be completed before the crane is allowed to be used. Only designated personnel may perform the required maintenance and repairs. The requirements of 29 CFR 1910.147, the control of hazardous energy or lockout/tagout, should be used to de-energize the crane (See Quick Tips #170: Lockout/Tagout for more information).

Operation

The manufacturer's instructions must be followed when operating to help ensure overhead crane safety. Attach the load to the block hook by means of slings or other approved devices, making sure the sling is clear of all obstacles. Once the load is properly secured and balanced in the untwisted sling, slowly raise the load. Horizontal movement must also begin slowly to prevent the load from swinging or coming into contact with other obstacles.

The crane warning signal or horn must be sounded when the load or hook comes near or over personnel. Carrying loads over personnel is not recommended. A load should not be left suspended.

Audible and discernible voice communication should be kept with the operator at all times. If this cannot be accomplished, a standard signal system should be used. However, it may be necessary to create special signals in certain circumstances. In these circumstances, the signals must be understood and agreed upon by all individuals using the crane.

Commonly Asked Questions

Q.		Where are the standard crane signals located?
A.		The signals are located in ANSI/ASME B30.2-2011. These are standard signals recommended by ANSI; however, OSHA does not require the signal system in its 29 CFR 1910.179, overhead and gantry crane regulation. The manufacturers of overhead cranes may also provide their own version of crane signals.
Q.		Do standards exist for other types of cranes?
A.		Yes, several. Here are just a few: OSHA 29 CFR 1910.180 regulates the operation of crawler locomotive and truck cranes; 29 CFR 1910.181 covers derricks; 29 CFR 1910.183 covers helicopter cranes; and 29 CFR 1910.178 covers powered industrial trucks. The ANSI/ASME B30.2 covers portal tower and pillar cranes; ANSI/ASME B30.5-2007 covers mobile and locomotive cranes; and ANSI/ASME B30.11-2010 covers monorails and underhung cranes.

Standard Hand Signals for Controlling Overhead and Gantry Cranes

Hoist: With forearm vertical, forefinger pointing up, move hand in small horizontal circle.	Lower: With arm extended downward, forefinger pointing down, move hand in small horizontal circles.
Bridge Travel: Arm extended forward, hand open and slightly raised, make pushing motion in direction of travel.	Trolley Travel: Palm up, fingers closed, thumb pointing in direction of motion, jerk hand horizontally.
Stop: Arm extended, palm down, move arm back and forth horizontally.	Emergency Stop: Both arms extended, palms down, move arms back and forth horizontally.
Multiple Trolleys: Hold up one finger for block marked "1" and two fingers for block marked "2." Regular signals follow.	Move Slowly: Use one hand to give any motion signal and place other hand motionless in front of hand giving the motion signal.
	Magnet is Disconnected: Crane operator spreads both hands apart—palms up.

Sources

29 CFR 1910.179, Overhead and Gantry Cranes
ANSI/ASME B30.2-2011, Overhead and Gantry Cranes

(Rev. 11/2012)

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Find even more information you can use to help make informed decisions about the regulatory issues you face in your workplace every day. View all Quick Tips Technical Resources at www.grainger.com/quicktips.

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