WORK-AT-HEIGHT

Working at heights

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Any work which is performed 2 meters above the ground level or below the ground level is known as work at heights. Most of the fall accidents happen while working at heights and most of them prove fatal. Working at heights is a high-risk activity. Every year workers are injured or die as a result of falling from ladders, scaffolds, roofs, etc. Falling is a risk faced by construction workers, painters, windows washers, firefighters, and others who work at heights.

According to some studies, approximately 40 percent of industrial accidents are happened during working at heights. So, it is very important to create a safe working environment and follow safe operating procedures while working at heights. The purpose of this article is to ensure safety while working at heights and some safety precautions to reduce deaths and injuries at work caused by height work or minimizing risks from working at height.

Working at heights hazards

  • Falling from a height.
  • Overturning and ejection of occupants from working platform.
  • Collisions.
  • Objects falling from a height.
  • Entanglement.
  • Trapping and crushing.
  • Electrocution.
  • Structural/mechanical failure and becoming stranded.
  • Suspension trauma.
  • Incorrect operation.
  • Lack of familiarisation and improper training.

Safety precautions of working at heights:

  • Avoid work at height wherever possible.
  • Make sure that the work platforms have guard rails and toe boards.
  • Check whether the scaffold and ladder are as per the standards.
  • Check that the tools/equipment and body harness are in good condition.
  • Workers suffering from balance disorders, vertigo, epilepsy, blackouts etc. should not be employed for height work.
  • Workers must be trained to know how to check, wear and adjust before they start work and how to connect themselves to the structure or safety line.
  • The workers should also be aware of emergency and evacuation procedures.
  • Make sure that the person is trained and aware of their work.
  • Ensure safety at work by good supervision.
  • Checks for whether the person is a certified rigger.
  • Checks for whether a person is fit for working at height.
  • Check for suitability of approaches like the physical condition of steps, rung ladders, and suitability of scaffolding, ramps, stairs, etc. With respect to load.
  • Ensure availability of personal protective equipment’s like helmets with chin strips & safety belts with arrangement for lifeline support.
  • Communicate with the person, working at height, about the hazards identified nearby.
  • Ensure that the area below the working platform is barricaded indicating danger.
  • Work at height must be planned, supervised and safe.
  • Prepare a written risk assessment
  • Use equipment that protects the largest number of people in preference to individual equipment
  • Ladders are only for work of short duration.
  • Maintain 3 points of contact
  • Protect all edges and openings where a fall could occur
  • Inspect the equipment used for work at height regularly.
  • Have rescue and emergency plans in place.
  • Tools should be attached by lanyard to the belt to prevent their fall on others.

Safety precautions before start the working at heights operation:

  • Ensure that the area below working platform is barricaded.
  • Check that workmen and equipment are not exposed to adverse weather like high wind, storm, lightning etc.
  • Ensure that the job is carried in presence of a competent Supervisor, who knows to deal with the emergencies.

Personal protective equipments for working at heights:

  • A hard hat (with a chin strap where appropriate)
  • Suitable safety footwear
  • Suitable high visibility vest or jacket
  • Suitable clothing for cold or wet weather conditions
  • Hearing protection
  • Eye protection
  • Hand protection
  • Full body harness with a short restraint type lanyard that can be connected to designated anchor points.

Safety tips for lifelines:

  • Minimum breaking strength 2000 Kilograms
  • Protected from abrasive or cutting edge
  • Workman should not hold it for balance
  • The lifeline should be a minimum of 12 mm dia. wire rope.
  • Not more than two persons shall be permitted to attach their lanyards to a single horizontal lifeline, at one time
  • The lifeline shall be anchored between two posts/supports not more than six meters apart
  • No more than one person may tie off to a vertical lifeline

Safety tips for anchorage point:

  • Must be independent of the working surface
  • Capable of supporting min. 2000 Kilograms
  • Located at or above shoulder height.

Safety tips for lanyard

  • Not longer than 1.8m.
  • Should have shock-absorbing properties (227-272 kg).
  • Tying of knots prohibited from lanyard to lifeline.
  • It shall not break under a minimum load of 2000 kg.
  • The lanyard shall meet the requirement of IS: 3521 (Or equivalent).

Safety tips for snap hook

  • Inspect regularly against wear, distortion, etc.
  • Two snap hooks shall not be connected to each other.

Safety tips for body harness

  • Inspect regularly against abrasion, broken stitching, missing hardware.
  • Instruct the workers about the use and care of the same.

Working at heights examples:

  • Installation and painting of overhead cranes, monorails, conveyors, piping.
  • Insulation of overhead piping.
  • Erection and painting of tanks, chimneys.
  • Construction of exterior brickwork, finishing and cladding work.
  • Erection and dismantling of scaffolds.
  • Working on pile driving rig.
  • Working on fragile roof.
  • Working on a ladder.
  • Working on trestle.

Types of Falls:

Fall of persons:

  1. Falls from height viz. structure, floor, ladder, scaffold, platform.
  2. Falls into depths (negative height) viz. wells, pit, sump, silos, ground opening, tank, vessel, excavation, ditches.
  3. Falls on the same level viz. falling or slipping on the floor.

Falling objects:

  1. Falls of objects from height viz. tools, machine part, equipment, material.
  2. Falls of objects from the hands of the same person viz. tool, equipment, material being handled.
  3. Structural collapse viz. wall, building, ceiling, pipe, ladder, scaffold, beam, truss etc.
  4. Material collapse viz. falling of piles of goods, layers of bags, cloth, paper rolls, carton boxes, grain cement and fertilizer.
  5. Slides and cave-ins viz. earth, rock, sand, stones, snow, ice etc.

Most serious accidents due to falls and struck by falling bodies take place in mining and quarrying, building and construction, structural repair, alteration, cleaning, painting, demolition, maintenance, and unsafe use of lifting and other equipment.

Major causes of work at height accidents are makeshift arrangement, unsafe floor, unsafe work practices, not using a helmet, safety belt, safety shoes, unsafe use of vehicles, poor supervision, poor lighting, etc.

Common causes of falls are:

  1. Water, oil or grease not cleaned up.
  2. Loose, defective and broken floor or toe board.
  3. Scrap, chipping and obstructions lying on the way.
  4. Dusty, steamy or smoky atmosphere restricting vision.
  5. Carrying too much load making it difficult to see over the load.
  6. Warn out or unsuitable footwear.
  7. Poor lighting, glare or shadows.
  8. Rushing instead of walking.
  9. Defective or weak scaffolds.
  10. Ladders, ramps, planks and platforms not rigid or safe for the job.
  11. No or inadequate hand rails.
  12. Climbing oddly instead of using ladder.
  13. Throwing instead of lowering tools or materials while working alone.
  14. Not using spectacles for clear vision.
  15. Not using crawling board on fragile roof.
  16. Not using safety belt or using in a wrong way, e.g. not tying its free end or tying it with a weak support.
  17. Not closing the man hole cover or floor opening etc.
  18. Allowing roof work and floor work at a time in the same vertical plane.
  19. Touching of crane boom, hook etc. to weak or unfastened structure.
  20. Non-compliance of statutory provisions.

Control measures for fall accidents:

  1. Safe, sound and dry non-slippery surfaces for walking and working added with fencing, guarding and toe-boards.
  2. Safe helmet, safety belt, foot wear to be used.
  3. Safe practice in walking and working. No excessive load lifting.
  4. Safe means of access while working at height.
  5. Use of crawling board, cat ladder, fall arrester net etc. while working on fragile roofs etc.
  6. Use of safety work permit for height work.
  7. Safe and sound stairs, ladders, scaffolds etc.
  8. Good lighting and supervision, cutting of power supply in overhead electric lines.
  9. Safety cordon to disallow persons in the area where any object may fall from height.

Causes of Fatal Injuries in the Construction Industry

  • 44 % Fall from height
  • 17 % Struck by moving vehicles
  • 17 % Trapped by collapse or overturning
  • 08 % Struck by moving / Falling object
  • 17%  Other .

Working at height safety

Falls happen due to falling from stairways, runs, ramps, gangways, floors, and ladders.

Stairways:

 The slope of stairways should be 30 – 35 degrees with the horizontal. The tread width should not be less than 24 cm plus a non-slip nosing of 2.5 cm. the riser height should not be more than 20 cm and not less than 12.75 cm and should be constant for each flight. All stairways should be fitted with railings on the open sides and handrails on sides that are otherwise enclosed. The height of the railings at the stairs should be not less than 75 cm or more than 90 cm measured from the top surface of the stair tread. The stair landings should be protected by railings and toe-boards. Non-skid strips on stair treads can prevent slipping.

  • Adequate lighting on the stairways should be provided to avoid accidents.
  • Two formulae are quoted in ILO literature:

    d + h=46 cm nose and I = d + n (d + 2h)

stairways
  • Where d is the depth of the step,
  • h is the height of the riser,
  • n the number of steps and
  • I the length of the landing.
  • Recommendation for h is 16 – 20 cm, and d should be 30 – 26 cm.

Ramps, Runways and Gangways:

  • The slope of ramps, runways and gangways etc. should be as small as possible and the recommended maximum is 15 degree to the horizontal.
  • Cleats not more than 40 cm apart, should be provided on ramps with steep slopes.
  • Toe boards should be provided where a ramp extends over a work place or a passage.
  • Wire screens are necessary on the sides, if there is a risk of materials falling through the sides.
  • Runways are long with uniform slope as they are at aerodrome.

Floors and platforms:

  1. The design should consider all types of loads from materials, persons and other forces.
  2. Unprotected floor edges situated at heights and openings, sumps, pits etc., in platforms or floors should be protected by railings, toe-boards or guards.
  3. Floors should be of sufficient strength and shall never be over loaded and should be non-slippery, free from holes, openings, pinch points, uneven surfaces, free from all dusts.
  4. Slope is an important factor in floor design. 1 – 2 % gradient towards drain helps ensure to flow away water and keep the surface dry.

Ladders:

  1. All ladders shall be designed to carry their intended load safely.
  2. side rails of metal ladders shall be of sufficient cross-section to prevent excessive deflection in use.
  3. Slip-resistant shoes, lashing or other effective means shall be used to avoid the danger of slipping.

Scafolding

  1. Scaffolding shall be designed by a qualified and competent Engineer.
  2. All tubes and coupler scaffoldings shall be constructed and erected to support 4 times the maximum intended loads.
  3. All posts shall be accurately spaced, erected on suitable bases (footplate / sole plate), and maintained plumb.
  4. Runners shall be erected along the length of the scaffolding located on both the inside and the outside posts at even height. Runners shall be interlocked to form continuous lengths and coupled to each post. The bottom runners shall be located as close to the base as possible. Runners shall be placed not more than 6.5 feet on centers.
  5. Bearers shall be installed transversely between posts and shall be securely coupled to each post bearing on the runner coupler. When directly coupled to the runners, the coupler shall be as close to the post as possible.
  6. Bearers shall be at least 4 inches but not more than 12 inches longer than the post spacing or runner spacing.
  7. Cross bracing shall be installed across the width of the scaffold at least every third set of posts horizontally and every fourth runner vertically. Such bracing shall extend diagonally from the inner and outer runners upward to the next outer and inner runners.
  8. Longitudinal diagonal bracing on the inner and outer rows of poles shall be installed at approximately a 45 degrees angle from near the base of the first outer post upward to the extreme top of the scaffolding. Where the longitudinal length of the scaffold permits such bracing shall be duplicated beginning at every fifth post.
  9. Similarly, longitudinal diagonal bracing shall also be installed from the last post extending bracing and upward toward the first posts, it may be attached to the runners.
  10. The entire scaffold shall be tied to and securely breast against the building at intervals not to exceed 9 M (30 feet) horizontally and 8 M (26 feet) vertically.

Working Platform:

  1. A working platform shall be designed to support the weight of the personnel and equipment to be used.
  2. The working platform shall be fully decked with scaffold boards.
  3. Scaffold boards should be secured to prevent displacement.
  4. The working platform shall be erected on the stable scaffold.
  5. Every working platform shall be provided with a ladder or any other safe means of access.
  6. Edges of the platform shall be provided with a guardrail. The height of the top rail shall be from 900 – 1200 mm. the mid-rail shall be provided halfway between the platform and the top rail on the inside of the posts. The toe guard shall be of a minimum of 100 mm height.
  7. Posts and rails shall be capable of withstanding a force of at least 900 N (22 lb) applied at any point or withstanding any load likely to be applied.
  8. Barriers shall be provided on open edges, holes, and openings of the platform.
  9. The minimum width of the working platform shall be as follows: 1. Only workmen – 600 mm. 2. men, tools, and materials – 900 mm. 3. men, tools, materials, and wheelbarrows – 1200 mm.

Genral Rquirements for working at height

  • All workers working at a height of more than 2 m  must wear safety harnesses i.e. safety belts connected with ropes. The belt should be tied with the body while the free end of the rope should be anchored with a fixed unbreakable sound structure or should be held by another person standing outside a confined space when the wearer is working inside. The belt and rope should be of sound material, examined by a competent person every six months,s and maintained in very good condition.
  • Workers should be trained, encouraged, and supervised to wear a safety belt properly because it can save their precious lives. All safety equipment is to be freely supplied by the employer and it should be seen that workers use them. Safety belts are required for workers working on towers, masts, windows, and building projects and also in confined spaces like tanks, boilers, gutters, etc.
  • The free end of the rope shall never be anchored on a structural member being placed or any loose or weakened structure. The supervisor and the worker must ensure this. Wrapping the free end (rope) on the waist is a wrong practice. Increasing the length of the rope without permission can also lead to hazards. Anchorage point should be at such height so that there shall be minimum slackness in the line. It shall never be lower than the belt attachment to the restraining line.
  • Safety block (like chain pulley block or hoisting drum block) is used to connect the wire rope with the safety belt to allow more freedom of movement. A sudden pull operates lock or brake to stop the rope. Because of a friction brake on the rope drum, the jolt is avoided and the falling person is stopped smoothly. In another design, a centrifugal brake is applied to the drum so that the person descends slowly to reach the ground.
  • Tensile tests and drop tests are carried out on safety belts and apparatus used with them. Safety belts should be kept in a cool, dry, and well-ventilated place. Regular cleaning, visual inspection for defects, and repair only by a competent person are necessary for good maintenance.

What is afety Belt?

Safety belts of various types are available. Pole safety belt, general-purpose safety belt with or without remote anchorage, and harness (man hoisting by another man) type safety belt are in common use. They are available in leather and webbing of natural and man-made fibers, of which, webbing is superior to leather. Webbing can withstand loads 3 to 4 times that of leather of the same size. Web material may be cotton, nylon, or dacron. While selecting a belt, its normal and emergency use should be considered. Life Lines of manila rope of 19 mm diameter or nylon rope of 13 mm diameter are suitable provided a shock-absorbing device is available. Care of belts is always necessary.

Types of safety belts

1.Genral purpose safety belt

It consists of a waist belt, a restraining line (lifeline), and metal components. Straps covering shoulders, chest, waist, and hips are preferable as by wearing it the forces during fall will be absorbed not only by the trunk but also by the legs. Choice of the model depends on the working method, time of work, environmental factors, etc. The rope (normally 2 m) is attached to the D ring secured to the waist belt.

For window cleaning, straps are long enough to fit windows and terminate in snap hooks for an anchor on each side of the window. Two restraining lines are used for the window cleaner’s belt.

2.Lineman’s or Pole Safety Belt :

To climb on poles, towers, masts, trees, etc. these belts are used. They are used as support while climbing and protection while falling. Here waist belt is fitted with 2 D-rings at different points. The length of the restraining line is adjustable by a buckle. Generally, fall is restricted to 60 cm.

3.Harness (Man hoisting) Safety Belt :

It is used for working in a confined space, silo, tank, vessel, etc. The lifeline is held by a person standing outside to rescue the wearer when he is unable to come out by his own efforts. On the rescue line, there is a wrist strap by which the wearer can be hauled up through a manhole or other opening.

Fall arrest system

A system is used to arrest a fall from a working level. A personal fall arrest system consists of an anchorage, connectors, a body harness, and may include a lanyard with a locking snap hook, deceleration device, lifeline, or a suitable combination of these. Here waist belt is connected to a sliding anti-fall device that automatically stops while moving in a fall direction.

Fall arrest systems are of two types:

  1. With a sliding and blocking device on a vertical safety support (pole, cable rail).
  2. With an automatic catching device for rolling, unrolling and blocking a tether (cable, rope, strap).

Some definitions:

Anchorage:

A secure point of attachment to which lifeline or lanyard are affixed (Capacity > 2000 Kilogram).

Connector:

A device for attaching a lifeline/lanyard etc. to the anchorage. A carabineer is an oval or trapezoidal-shaped connector with a gate/locking arrangement.

Lifeline:

A flexible vertical or horizontal line is secured to the anchorage to which a lanyard is attached.

Harness

The harness consists of a safety belt and rope or lifeline. It can stop a person from falling or he can be pulled out if working below in a confined space.

Full body harness:

A device with straps that can be attached to a personal fall-arrest system. The straps are fastened around a person’s body to contain the torso and distribute fall arrest forces over at least the upper thighs, pelvis, chest, and shoulders.

Retractable lifeline:

A fall-arrest device that allows free travel without a slack rope, but locks instantly when a fall begins. Retractable lifelines may be used when vertical movement is required but must be limited, such as in tanks, manholes, and pressure vessels, or on roofs.

Safety net

A safety net system is the least desirable fall-arrest system. If used below a work area where no gas cutting & welding jobs are involved, the system must be installed as close as practical under the walking or working surface. For overhead gas cutting & welding, fireproof tested nets are to be used, otherwise, all other means of fall arrest systems are to be used strictly. A safety net system must never be more than 30 feet (9.1 m) below the working surface.

 Safety nets shall be capable of absorbing an impact force equal to that produced by a drop test. The test if practicable & safe to drop a bag of sand as specified shall be conducted by dropping a 400-pound (180 kg) bag of sand 30 ± 2 inches (76 ± 5 cm) in diameter into the net from the highest walking or working surface at which employees are exposed to fall hazards. The drop distance shall never be less than 42 inches (1.1 m) above the net level.

A drop test must be conducted after initial installation and before use, whenever relocated, after major repair, and at six-month intervals, if left in one place. Safety nets shall be inspected at least once a week for wear, damage, and other deterioration. Materials, scrap pieces, and equipment and tools, which have fallen into the safety net, shall be removed as soon as possible but at least before the next work shift.

Work permit for working at heights

  • Check clearance with any power line or mobile equipment in the vicinity?
  • Communicate to the workmen about the possible hazards in the working area, like gas lines, power lines etc.

Safety precautions for mobile elevated working platform (MEWP)

  • Safe access to height.
  • Used infirm and level ground. Preparation required in advance.
  • To be placed away from the power line (>3.0m) and vehicular traffic approach.
  • Fall protection necessary second line of protection.
Mobile-elevated-working-platform
Mobile-elevated-working-platform(MEWP)

Safe methods for lifting the screw machine and other tools while working heights:

  • Each machine such as Screw Machine, Rivet Gun, Sheet Cutter etc. each to be placed in Separate appropriate bags. The small portion of the open end of the PP rope, provided with the machine, is to be hung outside the bag to facilitate holding while fixing to structure.
  • These bags to be lifted to the required height by means of Rope and Pulley system used for lifting of machine.
  • When these bags reach the required height, the open end of the PP rope tied to the machine is to be anchored first to the structure above by means of self-locking hook.
  • After anchoring the machine to the structure the machine is taken out from the bag for use.
  • The same system has to be followed for lifting machines by all the people working at different levels of the portable scaffolding.
  • When the machine is not in use, it is to be hung with the full body harness of the person with the 3rd latch provided with the machine or else it is to be kept in the covered box provided in the portable scaffolding.
  • While lowering the Screw Machine, Rivet Gun, Sheet Cutter etc. the machines are to be placed in the bag first and then only the two safety hooks are to be untied from the structure.

Dos and don’ts of working at heights:

Do’s of working at heights:

  • As much work as possible from the ground.
  • Ensure workers can get safely to and from where they work at height.
  • Ensure equipment is suitable, stable, and strong enough for the job, maintained and checked regularly.
  • Take precautions when working on or near fragile surfaces.
  • Provide protection from falling objects.
  • Consider emergency evacuation and rescue procedures.

Dont’s of working at heights:

  • Overload ladders – consider the equipment or materials workers are carrying before working at height. Check the pictogram or label on the ladder for information.
  • Overreach on ladders or stepladders.
  • Rest a ladder against weak upper surfaces, e.g., glazing or plastic gutters.
  • Use ladders or stepladders for strenuous or heavy tasks, only use them for light work of short duration (a maximum of 30 minutes at a time).
  • Let anyone who is not competent (who doesn’t have the skills, knowledge and experience to do the job) work at height.

Check lists for working at heights:

Sl. NoPoints to Check (GENERAL)YNNA
1.All the workers have been explained safe work procedures?
2.An effective communication system has been established and explained to the workers.
3.Adequate illumination has been ensured.
4.Work area inspected prior to starting of the job.
5.Work area inspected prior to starting of the job.
6.Workmen provided with bag/box to carry bolt, nuts, and hand tools.
7.Arrangement for fastening of hand tools made.
8.All work platforms are ensured to be of adequate strength and ergonomically suitable.
9.Fabricated makeshift arrangements are checked for quality and type of material, welding, anchoring, etc.
10.Work at more than one elevation at the same segment is restricted.
Sl.No.Points to Check (ACCESS & EGRESS)YNNA
1Walkways provided with handrails, mid-rails, and toe guards?
2All chequered plates, grating properly welded/bolted?
3Are ladders inspected and maintained in good condition?
4Are ladders spliced?
5Are ladders properly secured to prevent slipping, sliding, or falling?
6Do side rails extend 1m above the top of the landing?
7Are built-up ladders constructed of sound material?
8Rungs spacing should not be over 300 mm on the center.
9Metal ladders are not used along with electrical hazards.
10Ladders placed at the right slope.
11Ladders, staircases were welded/bolted properly.
12Any obstruction in the stair
13Are landings provided with handrails, knee rails, toe boards, etc?
14Whether ramp is provided with proper slope.
15Proper handrail/guards provided in ramps.
Sl.No.Points to Check (HOUSEKEEPING)YNNA
1Walkways, aisles, and all overhead work places cleared of loose material
2Flammable materials, if any, are cleared
3All shuttering materials are removed after de shuttering is done.
4Platforms and walkways free of oil/grease or other slippery spillages.
5Collected scrap is brought down or lowered down and not dropped from a height
Points to Check (PPE)
1Use of safety helmet, safety belts / full-body harness ensured for all workers.
2Anchoring point provided at all places of work.
3Common lifeline provided where ever linear movement at height is required.
4Safety nets are in use where ever required.
5A proper fall arrestor system is deployed at critical workplaces.
6Crawler boards/safety system for work on the fragile roof is used.

Faq’s of working at heights

What is height pass?

A document to be issued to a worker for working at height after imparting him the necessary training asserting his medical
Fitness and passing skill test.


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