Industrial Safety and Health for Goods and Materials Services - Chapter 16

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Thang đặt trên bề mặt không ổn định cán đạt quá xa để các bên (overreaching) Cán đứng quá cao trên bậc thang để duy trì thang cân bằng khuyết tật hoặc bị hỏng (ví dụ như bị phá vỡ đường ray hoặc nấc và phần cứng bị mất tích) Thang không có bảo đảm hoặc chuẩn bị tinh thần cán mang tải trong khi tăng dần và giảm dần Lựa chọn thang sai cho công việc (Hình 16.1) không đúng vị trí trên các bậc thang thời tiết tác dụng phụ như gió mạnh, mưa, nước đá, hoặc tuyết...

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Nội dung Text: Industrial Safety and Health for Goods and Materials Services - Chapter 16

16 Ladder Safety Ladders are one of the most useful tools in the workplace. When properly used ladders are one of the most useful tools available to workers. Improper uses, including the following, can result in injuries, falls, and deaths: . Ladders placed on unstable surfaces . Personnel reaching too far out to the sides (overreaching) . Personnel standing too high on the ladder to maintain balance . Defective or broken ladders (e.g., broken rails or rungs and missing hardware) . Ladders that were not secured or braced . Personnel carrying loads while ascending and descending . Selecting the wrong ladder for the job (Figure 16.1) . Improper position on the ladder . Adverse weather such as strong winds, rain, ice, or snow . Using a ladder to work on electrical conductors or power lines ß 2008 by Taylor & Francis Group, LLC.
Extension Decorator trestle ladder ladder Sectional/painter Platform Tripod ladder ladder ladder FIGURE 16.1 Select the proper ladder for the task. (Courtesy of Department of Energy.) This type of improper use of ladders results in an estimated 19,000 injuries and 24 fatalities per year according to Occupational Safety and Health Administration (OSHA). Falls or slips account for 80% of accidents and almost half fell at least 8 ft. While falling, 50% held on to other objects while 66% were not trained on how to inspect ladders and 73% were not instructed on the safe use of ladders. In 73% of accidents, the ladders involved were extension or straight ladders and in 20% they were step ladders. 16.1 LADDER SAFETY PROGRAM 16.1.1 MANAGEMENT’S COMMITMENT Employers need to ensure that they have policies for the use of ladders and workers need to understand that they are expected to comply with them such as the example in Figure 16.2. 16.1.2 TRAINING Employers have a tendency to think that all workers know how to use ladders in a safe manner. Many times it is the experienced worker who has a ladder accident. All Company ladder safety policy The _______________________ company is committed to preventing ladder related acci- dents. It is expected that the company rules and policies for ladder safety are to be followed by all employees. The company is committed to providing you with safe and appropriate ladders for your work activities. It is your responsibility to use ladders safely in accordance with the company ’s rules and policies and the ladder training which you have received. ___________________________Company President ’s Signature FIGURE 16.2 Ladder safety and use policy. ß 2008 by Taylor & Francis Group, LLC.
Ladder inspection form Location: Date: Name of Ladder Type Broken Damage to Wood, Soundness Any Other Inspector Serial # Parts Metal, Fiberglass Structurally Problems FIGURE 16.3 Ladder inspection form. employees including management and supervisors are to receive ladder safety train- ing. The content of the training shall include the following: . Company rules and policies . Accountability and responsibility . Ladder hazard recognition . Reporting and responding to ladder hazards . Safe use of ladders . Climbing safely 16.1.3 HAZARD IDENTIFICATION Before using a ladder all employees should inspect the ladder in accordance with the company’s ladder checklist (such as the one found at the end of this chapter) and use a ladder inspection form to document the inspection (Figure 16.3). If a faulty ladder having structural defects such as, but not limited to, broken or missing rungs, cleats, steps, broken or split rails, corroded components, or other defective components is found, the ladder should be removed from service and marked prominently as defect- ive or tagged with ‘‘Remove from Service. Do Not Use’’ until repaired or discarded. The supervisor should be notiﬁed of the unsafe ladder. The supervisor must assure the ladder is not used and it is either disposed of or repaired to a safe condition. Any ladder accidents should be investigated thoroughly by the supervisor and recommendations to prevent further occurrences should be made and implemented. 16.1.4 LADDER SELECTION A ladder should be selected based on its use and capacity. Ladders are classiﬁed in the following manner relevant to their load capacity (Table 16.1). TABLE 16.1 Ladder Use and Load Capacities Type Grade Duty (Load) Rating (lb) III Household 200 II Commercial 225 I Industrial 250 IA Extra heavy duty industrial 300 ß 2008 by Taylor & Francis Group, LLC.
TABLE 16.2 Stepladder Size Selection Chart Maximum Height Purchase This Size Highest Standing You Want to Reach (ft) Stepladder Level (ft) Level 7 3 11 in. 8 4 1 ft 11 in. 9 5 2 ft 10 in. 10 6 3 ft 10 in. 11 7 4 ft 9 in. 12 8 5 ft 8 in. 14 10 7 ft 7 in. 16 12 9 ft 6 in. 18 14 11 ft 5 in. 20 16 13 ft 4 in. Having the correct size ladder is imperative since using too short or too long a ladder is a common mistake that leads to potential hazards. You can use the distance between the rungs (1 ft) to estimate the height requirements. As for stepladders, the highest permitted standing level is two steps from the top. A worker standing high might lose his=her balance and fall. The maximum safe reaching height is about 4 ft higher than the length of the ladder. For example, a typical worker can reach 10 ft with a 6 ft ladder (Table 16.2). Extension ladders should be 7–10 ft longer than the highest support or contact point, which may be the wall or roof line. This will allow enough length for proper setup, overlap ladder sections (3 ft), height restrictions for the highest standing level, and, where appropriate, the extension of the ladder above the roof line. The highest standing level is four rungs from the top. Never stand on the ladder above the support points. Table 16.3 depicts the selection of length for extension ladders. The following points must be kept in mind when selecting a ladder: it should have unbroken rungs or steps and safety feet, functional spreaders that lock, it should comply with ANSI standards, must be of the right size, should not have TABLE 16.3 Extension Ladder Size Selection Chart Height to Top Buy This Size Extension Maximum Working Highest Standing Support Point (ft) Ladder (ft) Ladder Length (ft) Level 9 16 13 9 ft 2 in. 9–13 20 17 13 ft 1 in. 13–17 24 21 16 ft 11 in. 17–21 28 25 20 ft 10 in. 21–25 32 29 24 ft 8 in. 25–28 36 32 27 ft 7 in. 28–31 40 35 30 ft 6 in. ß 2008 by Taylor & Francis Group, LLC.
been painted or varnished, and should be made of ﬁberglass when used near electrical conductors since metal and wet wooden ladders will conduct electricity. 16.1.5 CONTROL PREVENTION AND As part of control and prevention of ladder accidents the following guidelines are to be used as constant reminders for the safe use of ladders. The setup of the ladder is very important in preventing accidents such as the following: . Place it on a level surface. . Use wide boards under it if you are on soft ground. . Place the feet parallel with the top support. . Anchor the top. . A straight ladder should extend 3 ft past the support point. . Tie or brace it at the bottom or have someone hold it. . Keep the ladder the right distance from the wall or support (use the 4 to 1 rule or 75.5) as seen in Figure 16.4. Raise an extension ladder before extending it. . If you place a ladder in front of a door, make sure the door is locked or blocked. Make sure areas of high trafﬁc are barricaded around the ladder. . . Maintain good housekeeping around the bottom of the ladder. As further guidance, the following dos and don’ts should be adhered to for prevent- ing accidents and injuries. min 3 ft rt th ppo leng p su king A to to Wor ance Dist A 4 FIGURE 16.4 The 4 to 1 rule for ladders. (Courtesy of Department of Energy.) ß 2008 by Taylor & Francis Group, LLC.
16.2 DOS Clean your shoes ﬁrst to remove mud, oil, and debris. . . Allow only one person at a time on a ladder. . Face the ladder while climbing up or down. . Have three points of contact when climbing (two hand and one foot or two feet and one hand). . Use the side rails for grip while climbing instead of the rungs. . Hold the ladder with both hands while climbing. . Hold the ladder with one hand while working. . Use a hanger or tool pouch for tools or a bucket. . Keep your weight centered between the rails. . Use nonslip gloves when climbing. 16.3 DON’TS . Try to use a ladder if it is scaffolding that you really need. . Carry objects while climbing. Use a special belt, tool pouch, or hoist materials up with a rope. . Step on the top two stepladder steps or the top three ladder rungs of an extension ladder. . Lean too far in either direction while working on a ladder. . Let your belt buckle go outside the rails. . Go near power lines or electricity with metal or wooden ladders. . Join or tie ladders together to have it extended. 16.4 USE OF LADDERS BY THE SERVICE INDUSTRY Many industry sectors may require ladders to extend a worker’s reach. The sectors that most require ladders are the utilities, warehousing, wholesale trade, retail trade, telecommunication (information), other service, and maintenance personnel in the leisure, hospitality, education, health care, and administration sectors. Depending on the frequency of use, the degree of training and attention to ladder safety will be determined by the amount of emphasis that is needed to continue a program for the safe use of ladders. 16.5 OSHA LADDER STANDARDS The following is a summary of the OSHA standards for ladders and not the complete regulation. 16.5.1 FIXED LADDERS (29 CFR 1910.27) A ﬁxed ladder must be able to support at least two loads of 250 lb each, concentrated between any two consecutive rungs. Fixed ladders must also support added antici- pated loads caused by ice buildup, winds, rigging, and impact loads resulting from ß 2008 by Taylor & Francis Group, LLC.
the use of ladder safety devices. Fixed ladders must be used at a pitch no greater than 908 from the horizontal, measured from the rear of the ladder. Individual rung=step ladders must extend at least 42 in. above an access level or landing platform either by the continuation of the rung spacings as horizontal grab bars or by providing vertical grab bars that must have the same lateral spacing as the vertical legs of the ladder rails. Each step or rung of a ﬁxed ladder must be able to support a load of at least 250 lb applied in the middle of the step or rung. The minimum clear distance between the sides of individual rung=step ladders and between the side rails of other ﬁxed ladders must be 16 in. The rungs of individual rung=step ladders must be shaped to prevent slipping off the end of the rungs. The rungs and steps of ﬁxed metal ladders manufactured after March 15, 1991, must be corrugated, knurled, dimpled, coated with skid-resistant material, or treated to minimize slipping. The minimum perpendicular clearance between ﬁxed ladder rungs, cleats, and steps and any obstruction behind the ladder must be 7 in., except that the clearance for an elevator pit ladder must be 4.5 in. The minimum perpendicular clearance between the centerline of ﬁxed ladder rungs, cleats, and steps, and any obstruction on the climbing side of the ladder must be 30 in. If obstructions are unavoidable, clearance may be reduced to 24 in., provided a deﬂection device is installed to guide workers around the obstruction. The step- across distance between the center of the steps or rungs of ﬁxed ladders and the nearest edge of a landing area must be no less than 7 in. and no more than 12 in. A landing platform must be provided if the step-across distance exceeds 12 in. (30 cm). Fixed ladders without cages or wells must have at least a 15 in. clear width to the nearest permanent object on each side of the centerline of the ladder. Fixed ladders must be provided with cages, wells, ladder safety devices, or self- retracting lifelines where the length of climb is less than 24 ft but the top of the ladder is at a distance greater than 24 ft above lower levels. If the total length of the climb on a ﬁxed ladder equals or exceeds 24 ft, the following requirements must be met: ﬁxed ladders must be equipped with either (1) ladder safety devices; (2) self- retracting lifelines and rest platforms at intervals not to exceed 150 ft; or (3) a cage or well, and multiple ladder sections, each ladder section not to exceed 50 ft in length. These ladder sections must be offset from adjacent sections, and landing platforms must be provided at maximum intervals of 50 ft (Figure 16.5). The side rails of through- or side-step-ﬁxed ladders must extend 42 in. above the top level or landing platform served by the ladder. Parapet ladders must have an access level at the roof if the parapet is cut to permit passage through it; if the parapet is continuous, the access level is the top of the parapet. Steps or rungs for through- ﬁxed-ladder extensions must be omitted from the extension; and the extension of side rails must be ﬂared to provide between 24 and 30 in. clearance between side rails. When safety devices are provided, the maximum clearance distance between side rail extensions must not exceed 36 in. Cages must not extend less than 27 in., or more than 30 in. from the centerline of the step or rung, and must not be less than 27 in. wide. The inside of the cage must be clear of projections. Horizontal bands must be fastened to the side rails of rail ladders or directly to the structure, building, or equipment for individual rung ladders. Horizontal bands ß 2008 by Taylor & Francis Group, LLC.
FIGURE 16.5 Example of a ﬁxed ladder. must be spaced at intervals not more than 4 ft apart measured from centerline to centerline. Vertical bars must be on the inside of the horizontal bands and must be fastened to them. Vertical bars must be spaced at intervals not more than 9.5 in., measured centerline to centerline. The bottom of the cage must be between 7 and 8 ft above the point of access to the bottom of the ladder, and the bottom of the cage must be ﬂared no fewer than 4 in. between the bottom horizontal band and the next higher band. The top of the cage must be a minimum of 42 in. above the top of the platform or the point of access at the top of the ladder. Provisions must be made for access to the platform or any other point of access. Wells must completely encircle the ladder. Wells must be free of projections. The inside face of the well on the climbing side of the ladder must extend between 27 and 30 in. from the centerline of the step or rung. The inside width of the well must be at least 30 in. The bottom of the well above the point of access to the bottom of the ladder must be between 7 and 8 ft. All safety devices must be able to withstand, without failure, a drop test consisting of a 500 lb weight dropping 18 in. They must permit the worker to ascend ß 2008 by Taylor & Francis Group, LLC.
or descend without continually having to hold, push, or pull any part of the device, leaving both hands free for climbing. All safety devices must be activated within 2 ft after a fall occurs, and limit the descending velocity of an employee to 7 ft=s or less. The connection between the carrier or lifeline and the point of attachment to the body harness must not exceed 9 in. in length. Mountings for rigid carriers must be attached at each end of the carrier, with intermediate mountings, spaced along the entire length of the carrier, to provide the necessary strength to stop workers’ falls. Mountings for ﬂexible carriers must be attached at each end of the carrier. Cable guides for ﬂexible carriers must be installed with a spacing between 25 and 40 ft along the entire length of the carrier, to prevent wind damage to the system. The design and installation of mountings and cable guides must not reduce the strength of the ladder. Side rails and steps or rungs for side-step ﬁxed ladders must be continuous in extension. Fixed ladders with structural defects—such as broken or missing rungs, cleats, or steps, broken or split rails, or corroded components—must be withdrawn from service until repaired. Defective ﬁxed ladders are considered withdrawn from use when they are (1) immediately tagged with ‘‘Do Not Use’’ or something to that effect, (2) marked in a manner that identiﬁes them as defective, or (3) blocked such as with a plywood attachment that spans several rungs. 16.5.2 PORTABLE LADDERS (29 CFR 1910.25 AND .26) Non-self-supporting and self-supporting portable ladders must support at least four times the maximum intended load; extra heavy-duty type 1A metal or plastic ladders must sustain 3.3 times the maximum intended load. The ability of a self-supporting ladders to sustain loads must be determined by applying the load to the ladder in a downward vertical direction. The ability of a non-self-supporting ladder to sustain loads must be determined by applying the load in a downward vertical direction when the ladder is placed at a horizontal angle of 75.58. When portable ladders are used for access to an upper landing surface, the side rails must extend at least 3 ft above the upper landing surface. When such an extension is not possible, the ladder must be secured, and a grasping device such as a grab rail must be provided to assist workers in climbing up and down. A ladder extension must not deﬂect under a load that would cause the ladder to slip off its supports. Ladders must be maintained free of oil, grease, and other slipping hazards. Ladders must not be loaded beyond the maximum intended load for which they were built nor beyond their manufacturer’s rated capacity. Ladders must be used only for the purpose for which they were designed. Non-self-supporting ladders must be used at an angle where the horizontal distance from the top support to the foot of the ladder is approximately one-quarter of the working length of the ladder. Wood job- made ladders with spliced side rails must be used at an angle where the horizontal distance is one-eighth the working length of the ladder. Ladders must be used only on stable and level surfaces unless secured to prevent accidental movement. Ladders must not be used on slippery surfaces unless secured or provided with slip-resistant feet to prevent accidental movement. Slip-resistant ß 2008 by Taylor & Francis Group, LLC.
feet must not be used as a substitute for the care in placing, lashing, or holding a ladder upon slippery surfaces. Ladders placed in areas such as passageways, door- ways, or driveways, or where they can be displaced by workplace activities or trafﬁc, must be secured to prevent accidental movement or a barricade must be used to keep trafﬁc or activities away from the ladder. The area around the top and bottom of the ladders must be kept clear. The top of a non-self-supporting ladder must be placed with two rails supported equally unless it is equipped with a single support attachment. Ladders must not be displaced or extended while in use. Ladders must have nonconductive side rails if used in proximity to exposed energized electrical equipment. The top step of a stepladder must not be used as a step. Crossbracing on the rear section of stepladders must not be used for climbing unless the ladders are designed and provided with steps for climbing on both front and rear sections. Ladders must be periodically inspected by a competent person for visible defects and after any incident that could affect their safe use. Single-rail ladders must not be used. When ascending or descending a ladder, the worker must face the ladder. Each worker must use at least one hand to grasp the ladder when climbing. A worker on a ladder must not carry any object or load that could cause him=her to lose balance and fall. A double-cleated ladder or two or more ladders must be provided when ladders are the only way to enter or exit a work area having 25 or more employees, or when a ladder serves simultaneous two-way trafﬁc. Ladder rungs, cleats, and steps must be parallel, level, and uniformly spaced when the ladder is in position for use. Rungs, cleats, and steps of portable and ﬁxed ladders (except as provided below) must not be spaced less than 10 in. apart, nor more than 14 in. apart, along the ladder’s side rails. Rungs, cleats, and steps of step stools must not be less than 8 in. apart, nor more than 12 in. apart, between centerlines of the rungs, cleats, and steps. Ladders must not be tied or fastened together to create longer sections unless they are speciﬁcally designed for such use. A metal spreader or locking device must be provided on each stepladder to hold the front and back sections in an open position when the ladder is being used. Two or more separate ladders used to reach an elevated work area must be offset with a platform or landing between the ladders, except when portable ladders are used to gain access to ﬁxed ladders. Ladder components must be surfaced to prevent injury from punctures or lacerations, and prevent snagging of clothing. Wooden ladders must not be coated with any opaque covering, except for identiﬁcation or warning labels which may be placed only on one face of a side rail. Portable ladders with structural defects—such as broken or missing rungs, cleats, or steps, broken or split rails, corroded components or other faulty or defective components—must immediately be marked defective, or tagged with ‘‘Do Not Use’’ or something to that effect and withdrawn from service until repaired. Ladder repairs must restore the ladder to its original design before the ladder can be reused. Under the provisions of the OSHA standards, employers must provide a training program for each employee using ladders and stairways. The program must enable each employee to recognize hazards related to ladders and stairways and to use ß 2008 by Taylor & Francis Group, LLC.
proper procedures to minimize these hazards. For example, employers must ensure that each employee is trained by a competent person in the following areas, as applicable: . The nature of fall hazards in the work area . The correct procedures for erecting, maintaining, and disassembling the fall protection systems to be used . The proper construction, use, placement, and care in handling of all stair- ways and ladders . The maximum intended load-carrying capacities of ladders used 16.6 LADDER CHECKLIST A checklist is an excellent method to determine ladder safety and OSHA compliance. Figure 16.6 depicts an example of a ladder checklist. Ladder checklist Answer the following questions yes or no to determine compliance or presence of ladder hazards: Yes & No & Are only Type 1 or Type 1A industrial ladders are used? Yes & No & Do steps on ladders a minimum load capacity of 250 lb? Yes & No & Are all ladders inspected for damage before use? Yes & No & Are ladders shall not placed against movable objects? Yes & No & Are ladders placed to prevent movement by lashing or other means? Yes & No & Are employees shoes are free of mud, grease, or other substances that could cause a slip or fall? Yes & No & Are ladders not placed on unstable bases such as boxes or barrels? Yes & No & Do employees not on the top two steps of a stepladder? Yes & No & Is a ladder used to gain access to a roof extends at least 3 ft above the point of support, at eave, gutter, or roof line? Yes & No & Are stepladders fully opened to permit the spreaders to lock? Yes & No & Are all labels in place and legible on ladders? Yes & No & Are ladder always moved to prevent and avoid overreaching? Yes & No & Are single ladders not more than 30 ft in length? Yes & No & Do extension ladders up to 36 ft have a 3 ft overlap between sections? Yes & No & Do extension ladders over 36 ft and up to 48 ft have a 4 ft overlap between sections? Yes & No & Do extension ladders over 48 ft and up to 60 ft have a 5 ft overlap between sections? Yes & No & Do two-section extension ladders not exceed 48 ft in total length? Yes & No & Do ladders ever two-section not exceed 60 ft in total length? Yes & No & Are ladders not used horizontally as scaffolds, runways, or platforms? Yes & No & Is the area around the top and base of ladders kept free of tripping hazards such as loose materials, trash, cords, hoses, and leaves? Yes & No & Is the base of a straight or extension ladders set back a safe distance from the vertical or approximately 1=4 of the working length of the ladder? FIGURE 16.6 Ladder safety checklist. (continued ) ß 2008 by Taylor & Francis Group, LLC.
Yes & No & Are ladders that project into passageways or doorways where they could be struck by personnel, moving equipment, or materials being handled, protected by barricades or guards? Yes & No & Do employees face the ladder when ascending or descending? Yes & No & Do employees must use both hands when going up or down a ladder? Yes & No & Are materials or equipment raised or lowered by way of lines? Yes & No & Are employees trained and educated on the proper use of ladders? Yes & No & Are repairs done professionally? Yes & No & Are inspections conducted before each use and defective, broken, or damaged ladders shall be pulled from service tagged and marked ‘‘Dangerous. Do Not Use?’’ Yes & No & Are the rungs tight in the joint of the side rails? Yes & No & Do all moving parts operate freely without binding? Yes & No & Are all pulleys, wheels, and bearings lubricated frequently? Yes & No & Are rungs kept free of grease and oil? Yes & No & Is rope that is badly worn or frayed replaced immediately? Yes & No & Are all ladders equipped with slip-resistant feet, free of grease, and in good condition? Portable wood ladders Yes & No & Are all wood ladders free of splinters, sharp edges, shake, wane, compression failures, decay, and other irregularities? Yes & No & Are portable stepladders no longer than 20 ft? Yes & No & Is the step spacing no more than 12 in. apart? Yes & No & Are stepladders which have a metal spreader or locking device of sufficient strength and size to hold the front and back when open? Portable metal ladders Yes & No & Are ladders inspected immediately when dropped or tipped over? Yes & No & Are the step spacing no more than 12 in. apart? Yes & No & Are metal ladders not for electrical work or in areas where they could contact energized conductors? Fixed ladders Yes & No & Are the steps shall no more than 12 in. apart? Yes & No & Are job made ladders constructed to conform with the established OSHA standards. Yes & No & Are all fixed ladders painted or treated to prevent rusting? Yes & No & Do fixed ladders 20 ft or higher have a landing every 20 ft if there is no surrounding cage? Yes & No & If it has a cage or safety device, a landing is required every 30 ft? FIGURE 16.6 (continued) ß 2008 by Taylor & Francis Group, LLC.