In November of 2013 a 51-year-old Massachusetts roofer fell to his death while performing routine roofing work on a condominium. OSHA launched a full investigation and concluded that this was an unnecessary and avoidable loss of a workers life. The employer, Fairview Contractors Inc. was subsequently fined nearly $120,000 in damages for not properly using guardrails and fall protection at the site.
This horrible event and others like it provide unsettling evidence for naming scaffolding the third most issued safety violation by OSHA in 2013. Scaffolding has always been one of the most hazardous elements to any construction or building site. Assembled on-site and for hundreds of different purposes, scaffolding is one of the most versatile and effective tools we have when erecting or maintaining a structure. This high level of versatility and mobility demands high levels of caution, safety, and preparation. If the necessary steps to ensure the safe use of scaffolding have not been taken, as seen in the case above and countless like it, the consequences can be dire.
Scaffolding is Ancient History
Scaffolding has been used for construction for hundreds, maybe thousands of years. It is theorized that our distant ancestors used primitive scaffolding to assist them when painting on cave ceilings or walls. It’s also debated if scaffolding systems helped ancient societies construct megalithic structures, such as the pyramids. In more recent history, scaffolding has been built with treated wood or bamboo, a practice still in use in parts of the world today. In the US, scaffolding is now made of either aluminum, steel or a composite material. It’s differentiated by the type of weld or joint used to hold the structure together as well as the specific purpose of the scaffolding. Identifying exactly what type of scaffolding being used is the first step in ensuring worker safety.
Prime Fall Hazard Culprit
Scaffolding is a major element in a larger arena of safety that OSHA calls, "Fall Hazards." A fall hazard is anything at your worksite that could potentially cause you to lose your balance or bodily support, resulting in a fall. It's clear to see how scaffolding quickly becomes the poster child for all fall hazards. OSHA claims fall hazards are the number one cause of all construction fatalities. Last year alone, nearly 300 workers were killed in construction-related falls. OSHA even includes a few case studies in their Fall Hazard Training Guide to drive home the true importance of keeping just basic scaffolding safe. In one such case, a construction worker fell 19 feet from a wall bracket scaffold, sustained blunt trauma to the head and later died. In another, a worker was killed in a fall from the third level of an unsafe tubular welded-frame scaffold while preparing masonry in icy conditions. While weather conditions always play a part of construction related accidents, OSHA attributes most scaffolding injuries to a lack of fall protection; use of aerial lifts without body belts and poor worker training. In a majority of the scaffolding related fatalities, the accidents are associated with factors like the planking or support giving way, or the lack of guardrails or failure of other fall protection.
Rules of Engagement
OSHA released a comprehensive set of guidelines for working with scaffolding in 1971. Then, in 1996 OSHA released an updated ‘Safety Requirements for Scaffolding 1910.28’ which is still in use today. The most notable update was the distinction between types of scaffolding and the specific safety concerns associated with each. While detailed inspections should be conducted regularly to assure safety and compliance, OSHA defines three main points in identifying safe scaffolding use:
- Proper Training – Every worker should be well acquainted with the tools they use. Scaffolding is no different- training should be provided to educate workers on the different parts of safely constructed scaffolding as well as any potential dangers.
- Correct Ladder and Guardrail Use – Size specific guardrails are required on any scaffolding or fall hazard more than 10 feet above the ground.
- Proper Personal Protective Equipment (PPE) – Specifically fall protection must be used at all jobsites where workers are exposed to potential hazards. OSHA generally requires fall protection be provided when working at four feet or higher in general industry, five feet in maritime and six feet in construction. Regardless of the fall distance, fall protection must be provided when work is being done over dangerous equipment and machinery.
General Construction Scaffolding Safety
The beginning point for scaffolding safety is erecting the scaffolding properly. The following are general rules for erecting scaffolding. There are many types of scaffolding. Always ensure the scaffolding you are using is erected in compliance with both OSHA standards and the manufacturer's instructions and recommendations.
Construction Scaffolding Erection General Guidelines:
- Scaffolds must be sound, rigid and structurally sufficient to support its own weight, plus four times the maximum intended load, without settling or displacement.
- Scaffolds must be erected on solid footings. Unstable materials such as boxes, barrels, loose bricks or concrete blocks must never be used to support scaffolding.
- Scaffolding may only be erected, moved, dismantled and altered under the supervision of a qualified competent person.
- Scaffold must be equipped with guardrails, midrails and toeboards.
- Any damaged or weakened component of a scaffold, including braces, brackets, trusses, screw legs or ladders, must be immediately repaired or replaced.
- Scaffold platforms must be tightly planked with scaffold plank grade material or the equivalent. Regular lumber may not be strong enough for scaffold planking. Verify the planking is scaffold grade, and that it is in good condition, before using it on a scaffold.
- The rigging on suspension scaffolds must be inspected by a competent person before the start of each shift and after any occurrence that could affect the structural integrity of the scaffold.
- Scaffolds must be at least 10 feet from electric power lines at all times.
Using scaffolding properly is important. The following general checklist covers the basics of safe scaffolding use:
- Any scaffold parts or components that are damaged should be immediately taken out of service.
- Scaffolds should never be altered. Never remove cross braces, toeboards, or other scaffold components.
- All scaffolds should be fully planked. Planks should not be painted, except at the platform ends.
- Scaffolds should never be moved horizontally while workers are on them, unless the scaffold is designed as a mobile scaffold and the workers are been trained in the proper procedures.
- No one is permitted on scaffolds when they are covered with snow, ice, or other slippery materials.
- No one is permitted on scaffolds in bad weather or when there are high winds, unless a qualified competent person has determined that it is safe to be on the scaffold.
- Ladders, boxes, barrels, buckets or other makeshift platforms should never be used to increase reach or work height.
- Extra materials, supplies, or debris may not allowed to build up on scaffold platforms.
- Scaffolds should not be loaded with more weight than they were designed to support. The weight on the scaffold should never exceed 25% of its rated capacity.
There are two basic types of scaffolding, suspended scaffold and supported scaffolds. The following two sections address safety when using each type of scaffolding.
Construction Scaffolding Safety - Suspended Scaffolds
Suspended scaffolds are platforms suspended from an overhead structure by cables or ropes, or by other non-rigid methods. There are a number of different types of suspended scaffolds, however two-point scaffolds are the most common type of suspended scaffold. Because of this we'll use two-point scaffolds as the example for safety requirements that apply to all types of suspended scaffolds.
Two-point adjustable suspension scaffolds are also known as swing-stage scaffolds. They are hung by ropes or cables connected to stirrups at each end of the platform. Two-point scaffolds are typically used by window washers on skyscrapers, but they play a prominent role in construction when building extremely tall structures and during maintenance.
Suspended Scaffold Safety - Fall Protection:
The number one scaffold hazard is worker falls. For suspended scaffolds OSHA requires both a personal fall arrest system (PFAS) and a guardrail system. Almost all accidents involving suspended scaffolding would not have led to fatality or injury if proper personal fall-arrest systems were being used. Most suspended scaffolding accidents involve two violations: one that causes the scaffold to fail, and the other resulting from workers failing to use appropriate safety harnesses, lanyards, lifelines, etc.
On suspended scaffolding guardrails must be installed along all open sides and the ends of the platforms. In addition to sturdy top rails, midrails, screens, mesh, intermediate vertical members, solid panels, etc., must be installed and be able to withstand a force of at least 150 pounds applied in any downward or horizontal direction, at any point.
Personal fall-arrest systems used on suspended scaffolds must be attached by a lanyard to a vertical lifeline, horizontal lifeline, or scaffold structural member. Vertical lifelines must be fastened to a fixed safe point of anchorage, independent of the scaffold, and they must be protected from sharp edges and abrasion. Safe anchorage points include structural members of buildings. Objects such as standpipes, drain pipes, vents, electrical conduit, and similar objects are not structural parts of the building and are never safe anchorage points.
Two or more vertical lifelines may not be attached to each other, nor to the same point of anchorage. This would result in a dangerous, unsafe condition.
Suspended Scaffold Structure - The Platform
Because the platform is the work area of a suspended scaffold, an inspection requires safety checks of both the platform structure and how the platform is used by the workers.
Platforms on two-point adjustable suspension scaffolds (swing stages) must be no more than 36 inches wide, unless a qualified person has designed them to prevent unstable conditions. Scaffold platforms and walkways must be a minimum of 18 inches wide, unless they are used in areas that the employer can demonstrate are so narrow that they must be less than 18 inches wide. In such cases, the platforms must be as wide as feasible.
Nothing that could cause a slip, trip or fall (i.e. tools, scrap material, chemicals, snow, ice, etc.) is allowed to accumulate on the platform. Makeshift devices, such as boxes and barrels, may not be used on top of scaffold platforms to increase the height of the working level. Ladders should not be used on scaffolds to increase the height of the working level.
For most activities, there must be no more than a 14-inch gap between the scaffold platform and the structure being worked on. For lathing and plastering, a gap of 18 inches is permitted.
Scaffold platforms must be able to support their own weight, plus four times the maximum intended load.
Suspended Scaffold Structure - Anchorage
A safe suspended scaffold begins with secure anchorage. The weight of the scaffold and its occupants must be adequately supported by both the structure to which it is attached, and by the scaffold components. Anchoring tiebacks must be secured to a structurally sound part of the building or structure. This does not include electrical conduit, vents, drain pipes, standpipes or other piping systems.
Tiebacks must be installed perpendicular to the face of the building or structure, or opposing angle tiebacks must be installed. Single tiebacks installed at an angle may not be used. When a counterweight system is used, only items specifically designed as counterweights may be used to counterweight a scaffold system.
Suspended Scaffold Safety - Access
Although people may access a suspended scaffold from a ladder, this is not recommended. The preferred industry practice is to access the scaffold from a rooftop or from the ground, and then raise or lower the scaffold to its working location.
Suspended Scaffold - Electrical Safety
Suspended scaffolds are often made of metal and at times may be used in close proximity to overhead power lines. This introduces the risk of electrocution. It is important that scaffolds be kept away from electrical wires. Scaffolds must be far enough away from power lines such that neither the scaffold, nor any conductive materials such as paint roller extensions, scaffold components or building materials, can come any closer than 10 feet to the power line.
Construction Scaffolding - Supported Scaffolds
Supported scaffolds consist of one or more platforms supported by poles, legs, uprights, outrigger beams, posts, frames, or other types of rigid supports. Because frame scaffolds are the most common type of supported scaffold, we'll use them to describe scaffolding safety tips that are common to all supported scaffolds.
Fabricated frame scaffolds are the most common type of scaffold because they are versatile, economical, and easy to use. They can be stacked several stories high for use on large-scale construction jobs including the outsides of buildings and other structures, the insides of large furnaces, and around tanks and silos.
Supported Scaffold Safety - Fall Protection
The number one scaffold hazard is falls. On supported scaffolding fall protection can be either a personal fall-arrest systems (PFAS) or a guardrail system. Fall protection must be provided on any scaffold that is ten feet or more above a lower level.
When vertical lifelines are used for fall protection, they must be fastened to a fixed safe point of anchorage that is independent of the scaffold. Safe points of anchorage include structural members of a building. Piping, or other non-structure components such as standpipes, drain pipes, vents and electrical conduit are not safe anchoring points. These may give way under the force of a fall. In addition, the vertical lifeline must be protected from sharp edges and abrasion.
When horizontal lifelines are used, they must be securely anchored to two or more structural members of the scaffold.
Guardrail systems must be installed along all open sides and ends of platforms. Midrails and toe boards are also required unless workers are always using a personal fall protection system.
Supported Scaffold Safety - Scaffolding Setup
It is impossible for a stable scaffold to be built on a foundation that is not square and level. Scaffold poles, frames and uprights be plumb and braced to prevent swaying and displacement. One of the most important tools when erecting a scaffold is a level.
Employers are required to assure that scaffolds are built within OSHA standards relating to strength and structural integrity. This means scaffolds must be capable of supporting their own weight and at least four times their maximum intended load.
Supported Scaffold Safety - Scaffolding Access
Climbing on or off a scaffold can be very hazardous. Employers are required to provide safe scaffold access. Workers must be able to safely access any level of a scaffold that is within two feet above or below an access point. Direct access to or from another surface is permitted only when the scaffold is not more than 14 inches horizontally and not more than 24 inches vertically from the other surface. Please note, OSHA standards specifically forbid climbing on cross-braces as a means of access. If a hook-on or attachable ladder is used, it must be specifically designed for use with the type of scaffold to which it is being attached.
Supported Scaffold Safety - Working Platform
Except when a scaffold platform is only used as a walkway, the platform is the work area. An inspection of the scaffold platform requires safety checks of both the platform structure, and how the platform is used by the workers.
Each platform must be fully planked or decked between the front uprights and the guardrail supports. No gaps greater than one inch are permitted between adjacent planks, or between the platform and the uprights, unless the employer can demonstrate that a wider space is necessary. If it is demonstrated a larger gap is needed, the gap will be as small as possible and under any circumstances cannot exceed 9½ inches.
Wooden planking must not be covered with opaque finishes, except for the platform edges which may be marked for identification. Platforms may be coated periodically with wood preservatives, fire retardants, and slip-resistant finishes, provided they do not obscure the top or bottom wood surfaces.
Scaffold platforms and walkways must be at least 18 inches wide, unless they are used in areas that the employer can demonstrate are so narrow that they must be less than 18 inches wide. In such cases, the platforms must be as wide as feasible, and fall protection must be provided in addition to a complete guard rail system.
Nothing that could cause a slip, trip or fall, such as tools, scrap material, chemicals, snow, ice, etc. may be allowed to accumulate on the platform.
Supported Scaffold Safety - Keeping Scaffolds Upright
Once a scaffold is erected, even if it is fully compliant with every OSHA standard relating to footings, structure, capacity, etc., it is not a safe work platform, if it does not remain upright. The rule of thumb is that a scaffold becomes inherently unstable once its height is four times its minimum base dimension. Weather conditions or damage to structural components can further reduce a scaffold's stability. When a supported scaffold needs to be higher than four times its minimum base dimension (4:1), it must be restrained by guys, ties, or braces to prevent it from tipping.
Supported Scaffold Safety - Electrical Hazards
Because scaffolds may be built in areas where there are overhead power lines, and because they are often made of metal, scaffolds can put workers at risk of electrocution. This risk can be eliminated by having sufficient clearance and proper maintenance.
Scaffolds must be far enough away from power lines such that any conductive material cannot come closer than ten feet to the power line. This not only includes the scaffold structure, but any poles, tools, extensions or other materials workers may hold or handle. Nothing must be able to come within ten feet of a power line.