251 Specialty There are a large number of scaffolds that are not widely used but rather are employed only in specific jobs. Some of the more common ones include the following: • Plasterers’, Decorators’, and Large-Area Scaffolds • Bricklayers’ Square Scaffolds • Horse Scaffolds • Form Scaffolds and Carpenters’ Bracket Scaffolds • Roof Bracket Scaffolds • Outrigger Scaffolds • Window Jack Scaffolds • Crawling Boards (Chicken Ladders) • Step, Platform, and Trestle Ladder Scaffolds Lesson Summary A scaffold refers to a temporary, elevated platform that is used to support workers and/or materials. There are several types of scaffolds: 1. Suspended scaffolds: the type that are suspended by a wire rope from a fixed overhead position (usually placed at the top of a building). They can be broken down further into the subcategories that include: Two-point (or swing stage) scaffolds; single-point adjustable (spider) scaffolds; catenary (using horizontal and parallel wire ropes); multi-point adjustable; interior-hung; float (ship); and more.
252 1. Supported scaffolds: the type that consist of one or more platforms elevated on poles and beams, which are placed upon a solid ground. They can be broken down into the following subcategories: Frame or fabricated; mobile; pump jack; and more. 2. Specialty scaffolds: includes decorators', plasterers', and large-area scaffolds, among others. Lesson 2: Overview of OSHA Directives for the Construction of Scaffolds Lesson Focus At the end of this lesson, students will be able to: • Describe how suspension scaffolds may be safely constructed • Describe how supported scaffolds may be safely constructed Suspension Scaffolds The regulations presented for the two-point (swing stage) scaffold are applicable to all other types of suspension scaffolds, unless stated otherwise. Two-Point (Swing Stage) Anchorage The anchorage is a key component contributing to the safety of a suspension scaffold. Because a suspension scaffold is, in effect, hanging from a structure, its weight must be sufficiently supported and balanced to ensure that it doesn’t plummet to the ground. The anchorage that the tieback is secured to must be capable of withstanding four times the intended load of the scaffold. The tiebacks should therefore not be secured to objects such as vents or piping but rather to structural members (foundation beams, for example).
253 Support: Suspension scaffolds are designed for vertical motion (that is, they move up and down); as such, the scaffold must be capable of supporting its own weight as well as that of the personnel and materials on it both while it is stationary and while it is in motion. The scaffold and its anchorage must be capable of handling up to four times the maximum intended load, and the support ropes must be capable of handling up to six times the intended maximum weight of the scaffold and its load. Scaffold components that have been manufactured by different manufacturers should not be mixed, unless specified. In addition, no modifications should be made to the scaffold components for any reason without approval from the manufacturer. Access: Though it is possible for suspension scaffolds to be accessed using ladders, it is a preferred practice to access the scaffold from the roof. Safe access methods are discussed in more detail in the next lesson. Fall Protection: Personnel working from suspension scaffolds may be a great distance above the ground; as such, a common accident is falls by workers from elevated positions. Both fall arrest systems and guardrails should be provided on any scaffold that is expected to be elevated to more than ten feet above the ground. This will be discussed in more detail in the next lesson. Platform: The platform is the part of the scaffold where the personnel work and the materials are placed. Each scaffold platform must be at least 18 inches wide and should be able to support its own weight in addition to four times the maximum allowed weight. For a two-point scaffold. The platform should be no more than 36 inches wide unless designed by a qualified person to prevent unstable conditions. The platform must be checked regularly to ensure that it meets the applicable safety standards. Stability: The scaffold must be designed in such a manner that it does not sway while it is being raised or lowered. In addition to the engineering methods that are employed to minimize horizontal movement of the scaffold, the employees working on the scaffold must exercise caution at all times. Electrical Hazards: Due to the fact that scaffolds are typically constructed primarily of metal, it is important that they remain clear of any electrical power sources, as this would increase the risk of electrocution. A minimum clearance to maintain from all electrical lines up to 50 kV is 10 feet. Unless the line is insulated and carrying less than 300 volts, in which case the minimum clearance to maintain is 3 feet. Lines carrying more than 50 kV require greater clearance distances as determined by OSHA 1926.451(f)(6). Personnel Training: One of the most important OSHA requirements relating to scaffolds is proper training by competent persons of the scaffold builders and those who are expected to work on the scaffold.
254 Single-Point Adjustable On a single-point adjustable scaffold, the support rope (the rope that is between the scaffold and the suspension device) must be maintained in a vertical position unless all of the following conditions are met: • The rigging has been designed by a qualified person. • The scaffold is accessible to rescuers. • The supporting rope is protected to ensure that it will not chafe at any point where a change in direction occurs. • The scaffold is positioned so that swinging cannot bring the scaffold into contact with another surface. Catenary Catenary scaffolds should not have more than two interconnected platforms at any one time. Furthermore, because catenary scaffolds do not usually have guardrails, all employees on a scaffold must be protected with personal fall arrest systems if operated at a height in excess of ten feet.
255 Multi-Point Adjustable On a multi-point adjustable scaffold, if bridges are not used, passage from one platform to another is only allowed when the platforms abut and are at the same height. These scaffolds should be suspended from metal outriggers, brackets, wire rope slings, hooks, or other means that meet the equivalent criteria for strength and durability. Furthermore, multiple multi-point scaffolds must not be bridged together unless the design of the scaffolds allows them to, the bridge connections are articulated, and the hoists are properly sized. Interior Hung Because interior hung scaffolds can only be suspended from the roof structure or other structural members, these structures must be inspected to ensure that they possess sufficient strength. Needle Beam Ropes or hangers must be used to support one end of a needle beam scaffold. The other end may be supported by ropes, hangers, or a permanent structural member. Needle beams need to be properly secured to ensure that they do not roll or are displaced. In addition, the platform needs to be securely attached to the needle beams with bolts or equivalent means. Float (Ship) Platforms for a float or ship scaffold must be secured to a minimum of two bearers (such as wooden beams) that extend to at least six inches beyond the platform on each side.
256 Rope connections must be secure so that the platform does not shift or slip. Each employee on a float scaffold must be protected by a personal fall arrest system if working at an elevation above ten feet. Supported Scaffolds The regulations presented for the frame or fabricated scaffold are applicable to all other types of supported scaffolds, unless stated otherwise. Fabricated Frame or Tubular Welded Frame Base Section: Supported scaffolds must be set on base plates or mud sills to ensure the stability of the structure. The footings of the scaffold must be capable of withstanding the load weight that is set upon it without movement or displacement. Frames and panels must be braced by cross, horizontal, or diagonal braces, or a combination of these. These frames and panels secure vertical members together laterally. The cross braces should be of the proper length to ensure that vertical members are square and aligned. With this system properly used, the completed scaffold is always plumb, level, and square. All brace connections should also be secured.
257 Support Structure: Two important factors in ensuring that the scaffold is stable and is not prone to swaying are its strength and the structural integrity of its supports. The supports of the scaffold must be capable of withstanding up to four times their intended maximum weight load as well as the weight of the structure. Access: Personnel are subject to accidents while they are climbing on or off a scaffold. The mode of accessing the scaffold must therefore be designed to ensure that employees are not needlessly being endangered, either while accessing the scaffold or by putting undue pressure on the structure. Employees are prohibited from climbing the cross-braces as a means of accessing the scaffold. This is extremely dangerous and may undermine the structural integrity of the structure. Fall Protection: Falls are a common hazard to the employees on scaffolds. The installation of proper fall protection minimizes the risk of such an occurrence. This may include the installation of guardrails on the platform or the use of personal fall arrest systems. Employees on scaffold platforms that are higher than 10 feet above the next level must be adequately protected from falling through the use of proper protective systems and practices.
258 Platform: The platform is the work area of the scaffold. It supports both the employees and the equipment and materials that they use. It is essential that the platform conforms to safety measures to ensure that the employees are not endangered in the course of their work. The platform should be fully planked, and the gaps between the planks should not exceed 1 inch. The platform should not be more than 14 inches from the structure being worked on unless guardrail systems are erected along the front edge and/or personal fall arrest systems are in use for all exposed employees. The maximum distance from the structure for plastering and lathing operations is 18 inches. Keeping Upright: Scaffolds that exceed a height four times their minimum base dimension must be restrained from tipping with ties, braces, guys, or equivalent means. Unless they have been designed for the specific purpose, scaffolds should not be moved horizontally while employees are on them. Electrical Hazards: As with suspension scaffolds, the height of supported scaffolds often means that they may be built within close proximity of power lines. In addition, the fact that scaffolds are often built using metal parts makes the risk of electrocution particularly high. As a result, specific measures must be taken to minimize the risk to employees.
259 Personnel Training: One of the most important OSHA requirements is the proper training, by qualified experts, of both the scaffold builders and those that are expected to work on the scaffold. Mobile While in motion, mobile scaffolds must be stabilized to prevent tipping over. When the scaffold is being moved manually, the force must be applied to an area that is as close to the base as possible and no more than five feet above the ground. If the scaffold is moved using a powered system, the system must be designed for that purpose. Scaffolds should not be moved horizontally while employees are on them, unless all of the following conditions are met: • The surface on which the scaffold is being moved is within 3 degrees of level and free of pits, holes, and obstructions. • The height to base-width ratio of the scaffold is two to one or less, unless the scaffold is designed and constructed to meet or exceed nationally recognized stability test requirements. • Required outrigger frames are installed on both sides of the scaffold. • When power systems are used, the force is applied directly to the wheels and generates a speed less than 1 foot per second. • No employee is present on any part of the scaffold that extends outward beyond the wheels, casters, or other supports.
260 Pump Jack The bracket and braces of the pump jack must be made from metal plates and angles to ensure strength. Each bracket must be fitted with two positive gripping mechanisms to prevent slippage. Poles must be secured to the structure by rigid triangular bracing at the bottom, top, and other points as needed. If the pump jack has to pass bracing that is already installed, an additional brace must be installed approximately four feet above the brace to be passed and must be left in place until the pump jack has been moved and the original brace reinstalled. If wood is used for poles, it must be straight-grained and free of shakes, dead knots, and other defects. Ladder Jack Support: Ladders that are used to support ladder jack scaffolds must be placed, fastened, or otherwise equipped with devices in such a manner so as to prevent the scaffold from slipping. They should also be appropriately fastened to ensure overall stability. Platforms: The maximum height at which a platform can be placed is 20 feet. Lesson Summary • There are safety requirements applicable to all scaffolds and additional standards applicable to specific types of scaffolds Unless otherwise stated, the safety regulations for the two-point scaffold apply to all other types of suspension
261 scaffolds. With suspended scaffolding, a primary factor to consider in terms of safety is the anchorage of the scaffold from the building (or other structure). • Additional requirements focus on how the scaffold is supported, how it can be accessed (preferably from the roof, rather than a ladder); fall protections, such as arrest systems and guardrails, which are required for any scaffold higher than ten feet in the air; and the platform, which must be at least 18" wide and able to support at least its own weight plus four times the maximum allowed weight. Many of these (not suspension-specific) requirements apply to supported scaffolds, as well. • Further safety requirements (which apply to both supported and suspended scaffolds) address stability (so the scaffold does not sway during its raising or lowering); control of electrical hazards (meeting the minimum 10-foot clearance from all electrical lines up to 50 kV, and other controls); and of vital importance to OSHA and worker safety, proper training to those building and working on scaffolds. Lesson 3: Scaffold Safety Measures Lesson Focus At the end of this lesson, students will be able to: • Explain how to minimize the risks associated with scaffolds • Describe how and why guardrails should be installed on scaffolds • Describe how and why a personal fall arrest system should be used • Describe the personnel requirements for scaffolding safety Introduction One out of every three deaths in construction results from a fatal fall. This high fatality rate indicates the importance of ensuring that scaffold workers are well protected against accidental falls. Generally, precautions must be taken for employees expected to work at heights above six feet. Fall protection is not required (but may be an excellent practice) for employees working on scaffolding at a height of ten feet or less. There is often very little space on a scaffold for a person to maneuver, especially when space is also taken up by the various materials that the employee needs to complete his or her job. This lack of space can be hazardous to anyone not taking the appropriate safety precautions. All employees must be trained by a qualified person to recognize the hazards associated with the type of scaffold being used and how to control or minimize those hazards. The training must cover fall hazards, falling object hazards, electrical hazards, the proper use of the scaffold, and the proper handling of materials.
262 How Do You Minimize the Risks? There are various strategies employers can use to minimize the risks to their employees of working on scaffolds. Uniformity • Ensure that the scaffold has been erected in accordance with the instructions of the manufacturer. • Do not alter or modify any of the components of the scaffold. If you are faced with a problem, contact the manufacturer. • If you have scaffolding components from two or more manufacturers, do not under any circumstances mix the components. • Do not use incompatible metals for the components of the scaffold. Guardrails All open and exposed sides of the scaffold at levels above ten feet should be fitted with guardrails to prevent falls or all exposed employees should be provided with proper fall arrest systems. The guardrails should consist of a least a top-rail, a mid-rail, and when necessary, a toe-board. Prohibit Climbing Prohibit climbing on the cross-braces of the scaffold because it is extremely dangerous and against OSHA regulations to use the cross-braces as a means of accessing the scaffold. Climbing the cross-brace can destabilize the scaffold and cause it to tip over. In addition, employees climbing up or down will not be protected by a personal fall arrest system and would be at an increased risk of falling. Provide safe ways to access the scaffold Provide the employees with personal fall arrest systems when appropriate (this will be discussed in more detail later in the lesson).
263 Guardrails If an employee is expected to work on scaffolding at heights that exceed ten feet, the employer must ensure that the scaffold is fitted with guardrails or that proper personal fall arrest systems are in use. If using guardrails, they should be installed along all open sides and ends before releasing the scaffold for use by employees, other than the erection and dismantling crews. However, guardrails are not required on the front end in the following instances: • When the front end of all platforms are less than 14 inches from the face of the work • When outrigger scaffolds are 3 inches or less from the front edge • When employees are plastering and lathing 18 inches or less from the front edge The following provisions must be met when installing guardrails. Top- and Mid-Rails The top-rail (the topmost part of the guardrail) must be between 39 and 45 inches above the platform or walking level of the scaffold. A mid-rail is the portion of the guardrail between the top-rail and the work platform. The mid-rail must be halfway between the top-rail and the surface of the platform. In case other structural panels must be installed (such as additional mid-rails), they should be installed so as not to leave openings that are wider than 19 inches. Toe-boards or mesh screening may also be installed, especially if there is any concern of accidentally falling objects striking workers below.
264 Strength of Guardrails Guardrails must be capable of withstanding up to 200 pounds of force applied to the top-rail at any point and from any direction. Mid-rails must be capable of withstanding up to 150 pounds of force applied at any point and from any direction. Smoothness The guardrails must not have any jagged or protruding surfaces that could cause punctures (either in clothing or in skin). In addition, the top-rail and mid-rails must be constructed in such a manner so as not to overhang the scaffold, thereby causing a projection hazard. Personal Fall Arrest Systems Personal fall arrest systems are one of the options that can be used to minimize the risks of injuries related to falls from an elevation. They should be used in the absence of, or instead of, a guardrail system if the employee is expected to work at heights exceeding ten feet. The following are some of the types and components of a personal fall arrest system. Body Harness Full body harnesses are designed to minimize the stress on the body that is induced by a fall. Employees must be trained by a competent person in fall protection systems prior to using a full body harness. Harnesses should be inspected prior to each use for mildew, wear, damage, and other deterioration. Defective harnesses should be removed from service.
265 Note: Due to high incidences of internal injuries suffered during falls, OSHA has concluded that body belts used for fall protection present a danger to workers and are no longer allowed. Lanyards/Vertical Lifelines Vertical lifelines consist of a line made of a strong material that is attached to an appropriate anchorage at one end and attached to the full body harness at the other end. Advances in synthetic materials have led to the creation of shock-absorbing lanyards with increased strength. Self-Retracting Lifelines (SRLs) SRLs are commonly used as an attractive alternative to fixed-length lanyards. The line is encased in a protective housing that extends and retracts automatically, which increases mobility and may reduce the risk of tripping. SRLs can be anchored to an appropriate anchorage point above an employee's head for increased safety and mobility. These devices are also commonly called "yo-yos."
266 Horizontal Lifelines Horizontal lifelines may be practical in areas where the possible anchorage points are otherwise limited or difficult to access. They are easy to transport and relatively quick to set up. The idea is pretty simple: Two anchorage points are connected to both ends of an extended cable that is run between them. PFAS Use Requirements The following are requirements for using a personal fall arrest system: • When stopping a fall, personal fall arrest systems should limit the maximum arresting force to no more than 900 pounds. • The line should be rigged to ensure that a worker does not freefall for more than 6 feet and does not come into contact with any surface. • The fall arrest system must have sufficient strength to withstand twice the potential impact energy of a worker freefalling for six feet. • Any systems that have been involved in a fall impact (that is, have been involved in arresting a falling worker) should be removed immediately and not used again until they have been inspected by a competent person to ensure that they are undamaged. • Workers who have been involved in a fall must be assisted immediately, or at least be in a position to rescue themselves—otherwise suspension trauma or other harm may result. This is a condition where pooling of the blood in the extremities may cause loss of consciousness or even death. To avoid this, when suspended, the worker must limit restriction points and move their arms and legs to maintain circulation. If the worker is unconscious when rescued, proper treatment and medical attention should be provided immediately.
267 • Ensure that regular checks are conducted on the systems for wear and tear and that any defective items are immediately replaced. • Do not, under any circumstances, attach a fall arrest system to guardrails. They are not designed for that purpose and are unlikely to withstand a fall impact. Case Studies There are numerous cases of severe injuries and death occurring when personnel working on scaffolds did not take the necessary safety measures or were not equipped properly. Here are some examples: • An employee was taking measurements from a scaffold not fitted with guardrails. He tripped and fell 14 feet to the ground. He died instantly. • A worker was working on a snow- and ice-covered scaffold with no guardrails or fall arrest system. He slipped and fell approximately 20 feet. He died instantly. • An employee was working on a scaffold during stormy weather. It is suspected he lost balance due to a strong gust of wind. He was not wearing a personal fall arrest system and fell 15 feet to his death. Personnel Requirements for Scaffolding Safety When is a competent person required for scaffolding? The OSHA standard pertaining to scaffolding requires a competent person to perform the following duties: • Select and direct employees who erect, dismantle, move, or alter scaffolds • Determine if it is safe for employees to work on or from a scaffold during storms or high winds and to ensure that a personal fall arrest system or wind screens protect these employees • Train employees involved in erecting, disassembling, moving, operating, repairing, maintaining, or inspecting scaffolds to recognize associated work hazards • Inspect scaffolds and scaffold components for visible defects before each work shift and after any occurrence which could affect the structural integrity and to authorize prompt corrective actions • Determine the feasibility and safety of providing fall protection and access for scaffold erectors and dismantlers When is a qualified person required for scaffolding? A qualified person must perform the following duties: • Design scaffolds and load them in accordance with that design • Train employees working on the scaffolds to recognize the associated hazards and understand procedures to control or minimize those hazards
268 • Design the rigging for single-point adjustable suspension scaffolds • Design platforms on two-point adjustable suspension types that are less than 36 inches wide to prevent instability • Make swaged attachments or spliced eyes on wire suspension ropes. • Design scaffold components construction in accordance with the design. When is an engineer required for scaffolding? The OSHA standard requires a registered professional engineer to perform the following duties: • Design the direct connections of masons’ multi-point adjustable suspension scaffolds • Design scaffolds that are to be moved when employees are on them • Design pole scaffolds over 60 feet in height • Design tube and coupler scaffolds over 125 feet in height • Design fabricated frame scaffolds over 125 feet in height above their base plates • Design brackets on fabricated frame scaffolds used to support cantilevered loads in addition to workers • Design outrigger scaffolds and scaffold components Lesson Summary • A scaffold must not just be anchored properly and be strong and stable; the workers themselves must be trained in how to safely use and maneuver (themselves and their equipment) in the often small space. • Employers can minimize the risk to employees by making sure all scaffolding construction, materials, and other elements are compatible. Scaffolds must contain safe, well-constructed guardrails that consist of three rails: top, mid, and, when necessary, a toe board or employees must be provided with appropriate personal fall arrest systems; guardrails must be sufficiently strong and smooth according to OSHA guidelines. • If an employee is expected to work on scaffolding at heights that exceed ten feet, the employer must ensure that the scaffold is fitted with guardrails or that proper personal fall arrest systems are in use. If using guardrails, they should be installed along all open sides and ends before releasing the scaffold for use by employees, other than the erection and dismantling crews. • Employers must also prohibit climbing on a scaffold's cross braces, and if there are no guardrails, provide personal fall arrest systems for workers. These systems may include body harnesses, vertical lifelines, self-retracting lifelines and horizontal lifelines, and must meet other OSHA requirements. • Personal fall arrest systems are one of the options that can be used to minimize the risks of injuries related to falls from an elevation. They should be used in the absence of, or instead of, a guardrail system if the employee is expected to work at heights exceeding ten feet.
269 Module 10: Tools - Hand and Power Module Description This module gives you a basic understanding about OSHA's role in the prevention and elimination of work-related illnesses and injuries. Hand and power tools are a part of our everyday lives and help us to perform tasks that otherwise would be difficult or impossible. However, these simple tools can be hazardous and have the potential for causing severe injuries when used or maintained improperly. Special attention to hand and power tool safety is necessary to reduce or eliminate these hazards. Module Learning Objectives At the conclusion of this module, students will be able to: • Discuss OSHA standards and rules associated with hand and power tools • Explore guarding techniques or principles that apply to hand and power tools • Identify the precautions that are essential for safe use of hand and power tools Lesson 1: Safe Use of Hand and Power Tools Lesson Focus At the end of this lesson, students will be able to: • Describe the general requirements for safely using hand and power tools • Describe the common hazards associated with hand and power tools • Describe the different kinds of switches and know which is appropriate Introduction Hand and power tools help us perform tasks that otherwise would be difficult or impossible. These tasks range from hanging a picture on your living room wall to cutting through slabs of concrete at a construction site. One thing that all tools—from hammers and handheld drills to hydraulic jacks and walk-behind saws—have in common is that they present hazards. Using them improperly or failing to properly maintain them can have dangerous consequences, both for you and for those around you. Some common hazards employees might encounter when using hand and power tools include falling, flying, abrasive, and splashing objects, as well as harmful dusts, fumes, mists, vapors, or gases. Employees who might encounter these hazards must be provided with the proper personal protective equipment (PPE) to keep them safe.
270 All employees should receive training on the proper use of any tools they will be using. This training should cover both how to properly use the tools and what safety precautions should be taken while using them. General Requirements The following are some basic tool safety rules that all employees should follow: • Inspect tools before use, perform maintenance regularly, and keep all tools in good working order • Use the right tool for the job. It should: o Fit the workspace available o Reduce the force you need to apply o Be ergonomic and fit comfortably in your hand o Be used in a comfortable work position • Only use a tool for the task it was designed to perform • Operate tools according to manufacturers’ instructions • Use the correct guards when necessary and ensure tools are safeguarded when not in use • Wear/use the correct PPE when necessary • Keep cutting tools sharp • Keep the floor and other worksurfaces free of debris or other tripping hazards If you observe any problems with tools, either during your inspection of the tool or while using it, bring it to the attention of the proper individual(s) immediately. Working with Tools at Height According to the Bureau of Labor Statistics (BLS), more than 50,000 occupational injuries occur each year as a result of falling objects—frequently, falling tools. As a result, working with tools at height requires additional precautions. Tool tethering refers to the practice of securing a tool to a worker or another anchor point in order to prevent it from falling and potentially injuring someone or causing damage below. Anyone working four feet or higher above the ground or above other coworkers should use tethered tools. Tools should also be tethered if they could damage other equipment or materials should they fall. If employees will be working with tools at height, employers must: • Secure tools and other materials to prevent them from falling • Erect barricades where necessary around hazard areas and post warning signs • Use toe boards and guardrails to prevent tools from falling from scaffolding • Use nets and canopies to catch or deflect falling objects
271 Additionally, when working at height, employees must NOT: • Prop or stand tools against the structure • Throw tools or objects up or down to other workers Tool tethers are the lanyards that connect tools to anchor points. If a tool does not already have a place to connect the tether, then a tool attachment should be installed in the field before the tool is used at height. The tool attachment should be positioned on the tool so that it does not interfere with its proper ergonomic use. In other words, ensure the tool functions the same as if the attachment was not there. Anchor attachments are designed to be field-installed on structures, scaffolding, equipment, and even workers. They provide anchor points for the tool tethers. Containers and bags may also be used to safely transport tools to and from heights. Keep tool tethers as short as possible without impeding your work. This helps prevent tangling or catching the tether on something. Retractable tethers are often a good option. When a tool tether is anchored to a worker’s body, try to limit the tool’s weight to six pounds. Dropping a heavy tool and having it catch on the tether could throw off your balance and lead to a fall. Hand Tools Hand tools are powered manually rather than with electricity or liquid fuel. Examples include hammers, axes, handsaws, wrenches, and screwdrivers. The most significant hazards commonly encountered while using hand tools result from misuse and improper maintenance. For instance: • If a chisel is used as a screwdriver, the tip of the chisel may break and fly off, hitting the user or another employee. • If the wooden handle on an axe or hammer is loose, splintered, or cracked, the head of the tool may fly off, hitting the user or another employee. • If the jaws of a wrench are sprung, the wrench might slip. • If impact tools like chisels, wedges, or drift pins have mushroomed heads, the heads might shatter on impact, sending sharp fragments flying toward the user or another employee. The employer is responsible for the safe condition of tools and equipment used by employees. Employers shall not issue or permit the use of unsafe hand tools and shall ensure employees have the proper training to use the necessary tools. When using sharp tools like saws, knives, and scissors, employees should direct the tools away from walkways, other workstations, and anywhere other employees might be working. Dull tools cause more injuries than sharp ones, so blades should be kept sharp. Cracked or otherwise damaged blades must be removed from use.
272 Iron and steel hand tools may produce sparks that can be an ignition source when near flammable substances. If work will be conducted near flammable gasses, highly volatile liquids, or explosive materials, employees should use spark-resistant tools, which are made of non-ferrous materials that will not spark when struck. Personal Protective Equipment (PPE) Personal protective equipment or PPE refers to clothing and other equipment worn by workers to protect them from hazards. OSHA requires that PPE: • Is of safe design and construction • Is maintained in a clean and reliable fashion • Is selected to account for workers’ fit and comfort (this encourages use) • Meets standards developed by the American National Standards Institute (ANSI) Employers are responsible for: • Performing a Job Hazard Analysis (JHA) of the workplace to identify and control physical and health hazards o During the JHA, the employer should consider possible dangers arising from impact, penetration, compression, heat or cold, harmful dust, radiation, and chemical and biological sources. • Identifying and providing appropriate PPE for employees • Training employees in the use and care of the PPE • Maintaining the PPE, including replacing it when it becomes worn or damaged • Periodically reviewing, evaluating, and updating the PPE program Employees are responsible for: • Properly wearing and using PPE • Attending training sessions on PPE • Caring for, cleaning, and maintaining PPE • Informing supervisors of the need to repair or replace PPE Eye and Face Protection OSHA suggests that eye protection be routinely considered for use by carpenters, electricians, machinists, mechanics, millwrights, plumbers, and pipefitters, sheet metal workers and tinsmiths, assemblers, sanders, grinding machine operators and handlers, and timber cutting and logging workers. In many cases, the hazards that require eye and face protection are caused by using tools. For example, chipping, grinding, sawing, or hammering might send metal or wood chips into your eyes. The right eye protection should:
273 • Protect against specific workplace hazards • Fit properly and be reasonably comfortable to wear • Provide unrestricted vision and movement • Be durable and cleanable • Allow unrestricted functioning of any other required PPE These are some common types of eye and face protection: • Safety spectacles have safety frames constructed of metal or plastic and impact-resistant lenses. • Goggles are tight-fitting eye protection that completely covers the eyes, eye sockets, and facial area immediately surrounding the eyes. They provide protection impact, dust, and splashes, and sometimes fit over corrective lenses. • Face shields are transparent sheets of plastic that extend from the eyebrows to below the chin and across the entire width of the head and protect from nuisance dust or splashes, but will not provide adequate protection against impact hazards. Head Protection Employers must ensure that their employees wear head protection if objects like tools might fall from above, or if they might bump their heads against fixed objects like exposed pipes or beams. Head protection is also required if there is a possibility of head contact with electrical hazards. Hard hats are a common type of head protection that is required PPE for anyone working under a scaffold or other raised area where tools are being used. Hard hats should: • Resist penetration by objects • Absorb the shock of a blow • Be water-resistant and slow burning • Have clear instructions for proper adjustment and replacement of the suspension and headband • Have a hard outer shell and a shock-absorbing lining • Allow sufficient ventilation for the wearer’s head • Fit the wearer comfortably • Be cleaned and inspected daily Foot and Leg Protection Employees who face possible foot or leg injuries from falling or rolling objects or from crushing or penetrating materials should wear protective footwear. Examples of such situations include: • When heavy objects such as barrels or tools might roll onto or fall on your feet
274 • Working with sharp objects such as nails or spikes that could pierce the soles or uppers of ordinary shoes • Exposure to molten metal that might splash onto feet or legs • Working on or around hot, wet, or slippery surfaces • Working when electrical hazards are present Hand and Arm Protection If a workplace Job Hazard Analysis (JHA) reveals that employees face potential injury to hands and arms that cannot be eliminated through engineering and work practice controls, employers must ensure that employees wear appropriate protection. Potential hazards include skin absorption of harmful substances, chemical or thermal burns, electrical dangers, bruises, abrasions, cuts, punctures, fractures, and amputations. Protective equipment includes gloves, finger guards, and arm coverings. Body Protection Body protection should prevent or mitigate the effects of temperature extremes, splashes of molten metals or other hot or hazardous liquids, and potential impacts from tools, machinery, and materials. Examples of body protection include laboratory coats, coveralls, vests, jackets, aprons, surgical gowns, and full-body suits. Duck, a closely woven cotton fabric, can protect against cuts and bruises when handling sharp or heavy objects, including certain hand and power tools. Hearing Protection Determining whether hearing protection is needed can be challenging. Exposure to excessive noise depends on many factors, including the loudness of the noise as measured in decibels (dB), the duration of each employee’s exposure to the noise, whether employees move between work areas with different noise levels, and whether noise is generated from one or multiple sources. Generally, the louder the noise, the shorter the exposure time before hearing protection would be required. If engineering and work practice controls do not lower employee exposure to workplace noise to acceptable levels, employees must wear appropriate hearing protection. It is important to understand that hearing protectors reduce only the amount of noise that gets through to the ears. The amount of this reduction is referred to as attenuation, which differs according to the type of hearing protection used and how well it fits. Hearing protectors worn by employees must reduce an employee’s noise exposure to within the acceptable limits noted in the table below.
275 These are some types of hearing protection: • Single use earplugs are made of waxed cotton, foam, silicone rubber, or fiberglass wool. They are self-forming and, when properly inserted, they work as well as most molded earplugs. • Pre-formed or molded earplugs must be individually fitted by a professional and can be disposable or reusable. If reusable, the earplugs should be cleaned after each use. • Earmuffs require a perfect seal around the ear. Glasses, facial hair, long hair, or facial movements such as chewing may reduce the protective value of earmuffs. Hazards of Hand and Power Tools Hand Tools The employer is responsible for the safe condition of tools and equipment used by employees. Employers should not issue or permit the use of unsafe hand tools. Employees should be trained in the proper use and handling of tools and equipment. Hand tool hazards are often caused by misuse and improper maintenance. Some examples include the following: • If a chisel is used as a screwdriver, the tip of the chisel may break and fly off, hitting the user or other employees. • If a wooden handle on a tool, such as a hammer or an axe, is loose, splintered, or cracked, the head of the tool may fly off and strike the user or other employees. • If the jaws of a wrench are sprung, the wrench might slip.
276 • If impact tools such as chisels, wedges, or drift pins have mushroomed heads, the heads might shatter on impact, sending sharp fragments flying toward the user or other employees. Do not use: • Wrenches when jaws are sprung • Impact tools (chisels and wedges) when heads have mushroomed • Tools with loose, cracked, or splintered handles • A screwdriver as a chisel • Tools with taped handles (they may be hiding cracks) Power Tools In addition to the general rules for tool safety, power tools require some additional consideration. This is because they present additional hazards, such as those related to working with electricity or those arising from the speed and force that power tools can generate. Some important rules for power tool safety include the following: • Do not lift or carry power tools by the cord • Keep electric power cords out of the path of the tool • Keep electric cords and hoses away from heat, oil, and sharp edges • Do not leave power tools unattended • Do not stand in water or on wet surfaces when running an electric power tool • Only use electric power tools with an adequate power supply • Do not use power tools or extension cords with a missing prong • Use only double insulated electrical tools • Use ground fault circuit interrupters (GFCIs) on all 120-volt, 15- and 20-amp branch circuits • Do not wear loose clothing, dangling objects or jewelry, or any appendage that could be snagged by a tool • Keep workplace floors clean and dry to prevent accidental slips • Keep all people not involved with the work at a safe distance • Avoid accidental starting; do not hold your fingers on the switch while carrying a plugged-in tool • Keep good footing and maintain good balance when using power tools • Remove damaged tools and tag them “do not use” Power tools must be fitted with guards and safety switches. The exposed moving parts such as belts, gears, shafts, pulleys, sprockets, spindles, drums, flywheels, chains, or other reciprocating, rotating, or moving arts must be guarded. Guards should also protect from flying chips and sparks. Safety guards should never be removed when a tool is in use. Portable circular saws with blades greater than 2 inches in diameter must be fitted with proper upper and lower guards.
277 Electric Cords • Don’t carry portable tools by the cord • Don’t use electric cords to hoist or lower tools • Don’t yank cord or hose to disconnect it • Keep cords and hoses away from heat, oil, and sharp edges Switches Hand-held power tools must be equipped with one of the following: • Constant Pressure Switch • Positive On/Off Switch • Momentary On/Off Switch Constant Pressure Switch Circular saws, chainsaws, and percussion tools without positive accessory holding means must be equipped with a constant pressure switch that will shut off when the pressure is released. Positive On/Off Switch This switch is used with many hand-held tools, including powered platen sanders, grinders with wheels two inches in diameter or less, routers, laminate trimmers, nibblers, shears, scroll saws, and jigsaws with blade shanks one-fourth of an inch wide or less. Momentary On/Off Switch Hand-held powered drills, tappers, fastener drivers, horizontal, vertical, and angle grinders with wheels greater than two inches in diameter, disc sanders, belt sanders, reciprocating saws, and saber saws must be equipped with a momentary contact "off" switch and may have a lock-on provided that they can be turned off by a single motion of the same finger that turned them on. Lesson Summary • The following are some basic tool safety rules that all employees should follow: o Inspect tools before use, perform maintenance regularly, and keep all tools in good working order o Use the right tool for the job. It should: Fit the workspace available Reduce the force you need to apply Be ergonomic and fit comfortably in your hand Be used in a comfortable work position
278 o Only use a tool for the task it was designed to perform o Operate tools according to manufacturers’ instructions o Use the correct guards when necessary and ensure tools are safeguarded when not in use o Wear/use the correct PPE when necessary o Keep cutting tools sharp o Keep the floor and other worksurfaces free of debris or other tripping hazards • Anyone working four feet or higher above the ground or above other coworkers should use tethered tools. Tools should also be tethered if they could damage other equipment or materials should they fall. • Hand tools are powered manually rather than with electricity or liquid fuel. Examples include hammers, axes, handsaws, wrenches, and screwdrivers. The most significant hazards commonly encountered while using hand tools result from misuse and improper maintenance. • In addition to the general rules for tool safety, power tools require some additional consideration. This is because they present additional hazards, such as those related to working with electricity or those arising from the speed and force that power tools can generate. • Hand-held power tools must be equipped with one of the following: o Constant Pressure Switch o Positive On/Off Switch o Momentary On/Off Switch Lesson 2: Classification of Tools Lesson Focus At the end of this lesson, students will be able to: • Describe the safety precautions necessary when operating the following kinds of tools: o Electric Power Tools o Pneumatic Tools o Liquid Fuel Tools o Powder Actuated Tools o Jacks General Safety Precautions Employees who use hand and power tools and are exposed to the hazards of falling, flying, abrasive, and/or splashing objects or harmful dusts, fumes, mists, vapors, and/or gases must be provided with the PPE necessary to protect them from those hazards. All hazards involved in the use of power tools can be prevented by following five basic safety rules:
279 3. Keep all tools in good condition with regular maintenance 4. Use the right tool for the job 5. Examine each tool for damage before use 6. Operate the tool according to the manufacturer's instructions 7. Provide and use the appropriate PPE. More Information: Employees and employers have a responsibility to work together to establish safe working procedures. If a hazardous situation is encountered, it should be brought to the attention of the proper individual(s) immediately. Electric Power Tools Good practices for the use of electric tools include the following: • Operate within design limits • Use gloves and safety shoes (Care must be exercised when using gloves with rotating power tools. In some cases, using gloves can become more dangerous as they may possibly come into contact with the rotating parts, thereby drawing the hand into the tool.) • Store in a dry place • Keep work areas well lit • Ensure that cords don’t present a tripping hazard Circular and Table Saws Injuries caused by circular and table saws are often severe, requiring stitches, surgery, and even physical therapy for recovery. Be especially careful when working with these types of power tools. Some things to keep in mind include: • Ensure the blade is appropriate for the saw by checking the size and speed rating. • Check the power cords for damage before using the saw. • Do not remove manufacturer’s guards! Holding the guard open exposes the spinning blade and greatly increases the chance of injury. • If using a table saw, adjust the base plate to keep as little of the blade as possible exposed below the material being cut. If using a circular saw, be careful to keep the exposed blade well above and away from hazards. • Wear the appropriate PPE, including eye protection. If cutting stone, masonry, or other materials that could throw off dangerous fragments, a face shield should be worn. • Power controls should be within easy reach of the operator. • Always make sure the material you are cutting is properly secured with clamps or other devices.
280 Chop Saws Chop saws are one of the most common power tools encountered in construction. When using, keep the following safety guidelines in mind: • Use protective guards properly and do not remove when the saw is in use. • Keep the saw clean of shavings and scraps. • Bring the blade up to speed before cutting. • Keep the material firmly against the blade and fence before cutting. • Do not leave the machine until the blade has come to a complete stop. • Keep your body and arms at a safe distance from the blade while operating it. • Use a clamp or vice to keep the saw secured to the work surface. Chainsaws Chainsaws are efficient, portable cutting tools, but they can be dangerous if not used correctly and carefully. Before using a chainsaw, always: • Ensure the area is marked and there are no unauthorized people nearby. If felling a tree, workers should be at least twice as far away as the height of the tree. • Identify and clear obstacles. • Identify electrical lines that might become hazards. • Ensure the chainsaw is the right size and type for the job, and check the controls, chain tension, and all bolts and handles for proper functioning. • Fuel the saw at least ten feet away from an ignition source. While using a chainsaw, always: • Start the saw on the ground or another firm support with the brake engaged. • Keep both hands on the handles and maintain secure footing. • Plan the cut; watch for objects under tension and use extreme care to bring objects safely to the ground. • Be prepared for kickback. • Never cut directly overhead yourself or others. • Operate only within your skill level, as accidents often result when operators perform tasks beyond their capabilities. • Wear proper PPE, including gloves, head protection, hearing protection, and eye and face protection such as safety glasses or goggles. Body protection should include heavy work pants. Grinders and Abrasive-Wheel Tools Abrasive wheels and tools may throw off flying fragments. Equip abrasive wheels with guards that:
281 • Cover the spindle end, nut, and flange projections. • Maintain proper alignment with the wheel. • Do not exceed the strength of the fastening. • Guard so that a minimal amount of the wheel is exposed. Before mounting, inspect abrasive wheels closely for damage and perform a sound or ring test to ensure that the wheel is free from cracks or defects. This test consists of gently tapping the wheel with a light, non-metallic instrument. If the wheel sounds dull or dead, it is likely cracked. DO NOT use it, as it could fly apart. Be sure to suspend rather than directly hold the wheel when performing the test (holding it could alter the sound a produce a false indication of defects). To prevent an abrasive wheel from cracking, fit it on the spindle freely, then tighten the spindle nut enough to hold the wheel in place without distorting the flange. Always let the tool come up to speed prior to grinding or cutting. Do not stand in front of the wheel as it comes up to speed and be sure to always use proper eye and/or face protection. Be sure to keep work rests not more than 1/8th inch from the abrasive wheel surface, and tongue guards at the top of the wheel not more than 1/4 inch from wheel surface. This prevents jamming the work between the wheel and the rest, which may cause the wheel to break. Do not adjust the wheel while it is rotating. Guarding Never remove guards or use a power tool without proper guarding in place. The removal of guards on moving parts may cause severe injury or even death to an employee or other persons near them. When using a powered grinder: • Always use eye or face protection. • Turn off the power when not in use. • Never clamp a hand-held grinder in a vise. The following information applies to guarding: • Guard exposed moving parts of power tools • Guard belts, gears, shafts, pulleys, sprockets, spindles, flywheels, chains, and other moving parts • Never remove a guard when a tool is in use Guarding—Point of Operation The point of operation is where the work is actually performed on the materials. The point of operation must be guarded or otherwise protected. Machine guards must protect the operator and others from:
282 • Point of operation • In-running nip points • Rotating parts • Flying chips and sparks You should never stand in the plane of rotation of the abrasive wheel as it accelerates to full operating speed. Portable grinding tools need to be equipped with safety guards to protect workers not only from the moving wheel surface, but also from flying fragments in case of wheel breakage. Radial Arm Saw Guarding The lower blade guard on a radial arm saw is designed to prevent the operator from coming into contact with the rotating blade. This guard must automatically return to the covering position when withdrawn from the work. Guarding Portable Circular Saws Guard these saws above and below the base plate or shoe. The upper and lower guards must cover the saw to the depth of the teeth. When withdrawn from the work, the lower guard must automatically return to the covering position. Table Saw Guarding Use a hood for guarding against contact with the upper blade. Table saws should be equipped with a spreader to prevent material from squeezing the saw or kicking back during ripping. It should also be equipped with anti-kickback fingers (or “dogs”) to hold the stock down in the event that the saw kicks back the material. Properly support all pieces of stock, including the cut and uncut ends, scrap, and finished product. Additionally, use a push stick for small pieces of wood and for pushing stock past the blade. Pneumatic Tools Pneumatic tools are powered by compressed air. Like tools powered by fuel or powder, pneumatic tools come with special safety considerations and additional rules. In particular, in a pneumatic tool the power source (the air) may not be delivered to the tool at a constant rate. If the pressure exceeds the manufacturer’s recommendation, the tool could break and injure the user or others nearby. Pneumatic tools can also cause noise hazards (discharged air can be very loud if not muffled) and temperature hazards (the discharged air is sometimes cold enough to cause frostbite on unprotected skin). Additionally, a severed air hose can whip around violently, causing injury. When using pneumatic power tools, remember the following safety guidelines:
283 • Hoses should be secured in such a way that they cannot become accidentally disconnected. • Safety clips should be securely installed and maintained to prevent attachments from accidentally disconnecting. • Nailers, staplers, and other similar pneumatic equipment with an automatic fastener feed should have a safety device to prevent the tool from ejecting fasteners. • Compressed air should not be used for cleaning purposes unless reduced to less than 30 pounds per square inch (p.s.i.). • Do not exceed the manufacturer’s safe operating pressure. • Do not use hoses to hoist tools or other materials. • All hoses more than ½ inch in diameter (interior) should have a safety device installed at the source of the supply line to reduce pressure in case of hose failure. • Spray guns should have automatic or visible manual safety devices to prevent accidentally pulling the trigger. • Ensure tool is fastened securely to the air hose to prevent a disconnection. Use a proper wire or positive locking device that attaches the air hose to the tool. Jacks Jacks are a type of hydraulic tool that uses fluid to create pressure and lift heavy loads. When using a jack, ensure that: • The base of the jack is on a firm, level surface • The jack is centered • The jack head is placed against a level surface • You apply the lift force evenly to the jack • The jack is lubricated and inspected regularly The manufacturer's rated capacity must be marked on all jacks and must not be exceeded. All jacks must have a stop indicator that must not be exceeded. Immediately block the load after it is lifted. Put a block under the base of the jack when the foundation is not firm and place a block between the jack-cap and load if the cap might slip. Proper maintenance of jacks is essential for safety. All jacks should be lubricated and inspected regularly. Pneumatic Tool Safety • All pneumatic driven nail guns, staplers, and other similar equipment with automatic fastener feeds, should have a safety device on the muzzle to prevent the tool from ejecting fasteners, unless the muzzle is in contact with the work surface.
284 • The manufacturer's safe operating pressure for hoses, pipes, valves, filters, and other fittings should not be exceeded. Eye protection must be worn while operating pneumatic tools. • Hearing protection is typically required while operating jackhammers due to the high noise levels generated. • Compressed air hoses with an inside diameter (ID) greater than one half (1/2) inch must have a safety device in place to reduce pressure in case of hose failure. Compressed Air Cleaning Do not use compressed air for cleaning. The only exception allows compressed air to be used for cleaning where it is reduced to less than 30 P.S.I. with effective chip guarding and PPE, and where appropriate controls are in place to prevent injuries and damage. Liquid Fuel Tools Like electric power tools, fuel-powered tools present specific additional hazards that workers and employers must consider. Most fuel-powered tools use gasoline and the main hazards arise from fuel vapors and exhaust. As a result, they should not be used in enclosed and confined spaces. Use only approved flammable liquid containers to transport fuel, and always shut down the engine and allow it to cool before refilling a fuel-powered tool tank. When a fuel-powered tool is used inside a closed area, effective ventilation and/or proper respirators must be utilized to avoid breathing carbon monoxide. Fire extinguishers must also be available in the area. Powder-Actuated Tools Powder-actuated tools use the expanding air generated by an explosion to drive a fastener into materials like concrete and masonry. This makes them especially hazardous—in many ways, a powder-actuated tool is like a loaded gun and should be treated like one. Here are some rules for using a powder-actuated tool: • The user must be trained to operate it! • It must be inspected and tested each day before loading to ensure the safety devices are working properly. • The user muse wear proper ear, eye, and face protection. • Select a powder level that will do the work without using excessive force. • Do not use powder-actuated tools in explosive or flammable environments. • Ensure the tool is clean, its moving parts operate freely, and its barrel is free of obstructions. • Ensure the tool has the proper shielding and guarding attachments.
285 • Do not load a tool unless it will be immediately used. • Do not leave a loaded tool unattended. • Keep your hands clear of the barrel-end of the tool and never point it at anyone. • Store unloaded tools in a locked box. Easily Penetrated Material Avoid driving into materials easily penetrated unless materials are backed by a substance that will prevent the pin or fastener from passing through. Also, don't drive fasteners into very hard or brittle material that might chip or splatter, or make the fasteners ricochet. Powder-Actuated Tool Safety Tips The following safety tips apply to the use of powder-actuated tools: • Do not use powder-actuated tools in explosive or flammable environments. • Inspect powder-actuated tools before use to ensure: o The tool is clean o That moving parts of the tool operate freely o The barrel of the tool is free from obstructions and has the proper shield, guard, and attachments • Do not load the tool unless it will be immediately used. • Do not leave a loaded tool unattended. • Keep hands clear of the barrel end of the tool. • Never point the tool at anyone. • Store unloaded tools in a secured box. If a powder-actuated tool misfires, the user must hold the tool in the operating position for at least 30 seconds before trying to fire it again. If it still will not fire, the user must hold the tool in the operating position for another 30 seconds and then carefully remove the load in accordance with the manufacturer’s instructions. This procedure will make the faulty cartridge less likely to explode. The bad cartridge should then be put in water immediately after removal. Case Study What Happened? An employee was killed when he was struck in the head by a nail fired from a powder actuated tool. The tool operator was attempting to anchor a plywood form in preparation for pouring a concrete wall. Description of the incident: A 22-year-old carpenter’s apprentice was killed when he was struck in the head by a nail fired from a powder-actuated nail gun. The nail gun operator fired the gun while attempting to anchor a plywood concrete form causing the nail to pass through the
286 hollow form. The nail traveled 27 feet before striking the victim. The nail gun operator had never received training on how to use the tool, and none of the employees in the area were wearing PPE. In another situation, two workers were building a wall while remodeling a house. One of the workers was killed when he was struck by a nail fired from a powder-actuated nail gun. The tool operator who fired the nail was trying to attach a piece of plywood to a wooden stud. But, the nail shot through the plywood and stud, striking the victim. Below are some OSHA regulations that should have been followed. • Powder-actuated nail guns should not be used to drive nails into easily penetrated materials unless the material is backed by a substance that will prevent the nail from passing through. • Employees who operate powder or pressure-actuated tools must be trained to avoid firing into easily penetrated materials (like plywood). • In areas where workers could be exposed to flying nails, appropriate PPE must be used. Lesson Summary • Electric power tools must be double insulated and have a three-wire cord plugged into a grounded receptacle. When using power tools, you should use gloves and safety shoes, keep work areas well lit, and ensure that cords don't present a tripping. Don't use power tools in wet locations unless approved for those conditions. • Abrasive wheels and tools may throw off flying fragments and should have guards and be inspected before use. Never remove guards or use a power tool without proper guarding in place. The point of operation must be guarded or otherwise protected. • The lower blade guard on a radial arm saw is designed to prevent the operator from coming into contact with the rotating blade. This guard must automatically return to the covering position when withdrawn from the work. • Pneumatic tools are powered by compressed air and they include nail guns, staplers, chippers, drills, and sanders. Hazards include getting hit by a tool attachment or by a fastener that worker is using with the tool. They should have a safety device on the muzzle to prevent the tool from ejecting fasteners, unless the muzzle is in contact with the work surface. • Powder-actuated tools use the expanding air generated by an explosion to drive a fastener into materials like concrete and masonry. This makes them especially hazardous—in many ways, a powder-actuated tool is like a loaded gun and should be treated like one. • Avoid driving into materials easily penetrated unless materials are backed by a substance that will prevent the pin or fastener from passing through. Do not use powder-actuated tools in explosive or flammable environments.
287 • Most fuel-powered tools use gasoline and the main hazards arise from fuel vapors and exhaust. As a result, they should not be used in enclosed and confined spaces if it can be avoided. Use only approved flammable liquid containers to transport fuel, and always shut down the engine and allow it to cool before refilling a fuel-powered tool tank.