Working at height remains one of the biggest causes of fatalities and major injuries. Common cases include falls from ladders and through fragile surfaces. ‘Work at height’ means work in any place where, if there were no precautions in place, a person could fall a distance liable to cause personal injury (for example a fall through a fragile roof).
Work at Height incidents can be avoided by following any of the below mentioned controls:
- Avoid work at height where it’s reasonably practicable to do so
- Where work at height cannot be easily avoided, prevent falls using either an existing place of work that is already safe or the right type of equipment
- Minimise the distance and consequences of a fall, by using the right type of equipment where the risk cannot be eliminated
This last point can be done either by using restraint PPE to stop the worker from reaching a fall hazard. The fall hazard could be an unprotected roof edge or an opening at ground level (such as an open manhole) or by using Fall Arrest PPE to limit the distance and consequences of a fall. This option should always be the last resort and must also include adequate means of rescue.
Arresting a fall is only the first step in preventing injury or death. Even if the arrest does not cause injury, a fallen worker can die from suspension trauma (orthostatic shock) if not rescued in time. Too often, a worker is saved by a personal fall arrest system (PFAS), only to succumb to suspension trauma while waiting for rescue.
Personal Fall Arrest System
A fall arrest system provides maximum freedom of movement for the worker; however, in doing so, it also enables the worker to reach a position where an accidental fall could occur. In the event of a fall, the fall arrest system ensures the worker will be caught before descending. Fall arrest equipment must be selected and positioned to limit the distance and consequences of the fall.
When using fall arrest systems, it’s essential that you always use the correct equipment. A fall arrest system should be used where it is not possible to restrict the worker from reaching a fall hazard. Fall arrest systems would typically be used when work needs to be completed on fragile surfaces or when the worker is required to work over the leading edge of a fall hazard. Following a fall, consideration must be given to the rescue of the worker. There are three vital components that make up a complete fall protection system. These are the ABCs of fall protection: Anchorage, Body support and means of Connection.
“too often, a worker is saved by a personal fall arrest system (PFAS), only to succumb to suspension trauma while waiting for rescue”
Each one must be in place and properly used to provide maximum worker protection. While each of these components is vital to worker safety, the connecting device is the critical link in assembling a safe fall protection system since it bears the greatest force during a fall. Careful consideration must be given to the selection, materials, construction and inspection/maintenance of fall protection equipment before, during and after a connecting device has been selected.
Anchorage is a secure point of attachment for lifelines, lanyards or deceleration devices and Anchorage Connector to refer to the component by which the connecting device is coupled to the anchorage. It may be a beam anchor, cross-arm strap, D-bolt, hook anchor, tripod, davit or other secure device that serves as a point of attachment for lifelines, lanyards or deceleration devices.
A body support, or body wear, is the component that is worn on or around the torso. Body belts and full body harnesses are the two most common body supports. A body support, or body wear, is the component that is worn on or around the torso. Body belts and full body harnesses are the two most common body supports. A body belt is a belt that circles the waist and is used for worker positioning and fall prevention. A body belt may be supplied with D-rings on the hips and/or middle of the back.
A full body harness is a body support device that distributes fall arrest forces across the shoulders, thighs and pelvis. Full body harnesses have a centre back fall arrest attachment for connection to the fall arrest connecting device and may have other D-rings for use in worker positioning, fall prevention, suspension or ladder climbing. The connecting subsystem is the critical link which joins the body wear to the anchorage/ anchorage connector. It can be an energy-absorbing lanyard, fall limiter, self-retracting lanyard, rope grab, or retrieval system.
Connecting means will vary depending on whether the worker is equipped for personal fall arrest or work positioning and travel restriction. Personal fall arrest systems must be selected and rigged to ensure that potential free fall distances will never exceed 6 ft (1.8 m). See manufacturer’s instructions for connecting subsystems to determine the deceleration distance and elongation that must be taken into consideration.
Calculating Fall Distance
Total fall distance is the sum of free fall distance and deceleration distance. Dynamic elongation of the system (temporary elastic stretch of connecting components and subsystems) and the worker’s height must be added to total fall distance and the user must allow for clearance. It is prudent to allow for an additional safety factor of 3 ft (1 m) below the fallen worker’s feet. Potential fall distance must be calculated to determine how to rig the system, and selection of the appropriate type of connecting device. For example, when using a 6-foot lanyard, the illustration below shows a typical calculation of total estimated fall distance.
“If a fall has been arrested, remove all components of the system from service and follow the manufacturer’s instructions for disposal.”
For the example shown: When fall clearance is under 18.5 ft (5.6m), an alternative solution such as a shorter lanyard length, or a different connecting device such as a self-retracting lanyard or fall limiter, is needed to reduce the total fall distance. When fall clearance is over 18.5 ft. (5.6m) there is sufficient total fall distance available, and the 6 ft lanyard is acceptable to use. Note that energy absorbing lanyards can expand up to 3.5 ft (1.1m). Never tie a knot in any lanyard to make it shorter, as it reduces the strength by more than 50 per cent. Instead, purchase an adjustable lanyard and adjust it to proper working length.
Inspection of Equipment
Fall protection equipment must be visually inspected before each use. Regular inspection by a competent person for wear on the equipment should be performed at least every six months. Severe service or wear will require more frequent inspections.
Inspection procedures should be written, and each inspection should be documented. It is also important to follow any specific instructions that are provided with the equipment at the time of purchase. Instructions should be stored in a location where they are readily available to the users. Inspect all equipment according to the manufacturer’s instructions. If required by the manufacturer, return the equipment to the manufacturer for inspection, repair, or recertification. Remove equipment from service if a stress indicator or warning system has been activated.
Follow manufacturer’s instructions for disposition of the equipment. If a fall has been arrested, remove all components of the system from service and follow the manufacturer’s instructions for disposal.
To inspect your harness or body belt, perform the following procedures.
Webbing – Grasp the webbing with your hands 6 in. (152mm) to 8 in. (203mm) apart. Bend the webbing in an inverted “U”. The surface tension resulting makes damaged fibres or cuts easier to detect. Follow this procedure the entire length of the webbing, inspecting both sides of each strap. Look for frayed edges, broken fibres, pulled stitches, cuts, burns and chemical damage.
Rings/back pads – Check D-rings for distortion, cracks, breaks, and rough or sharp edges. It should pivot freely. D-ring back pads should also be inspected for damage.
Attachment of buckles – Inspect for any unusual stitching of the buckle or D-ring attachments.
Tongue/grommets – The tongue receives heavy wear from repeated buckling and unbuckling. Inspect for loose, distorted or broken grommets. Webbing should not have additional punched holes.
Tongue buckles – Buckle tongues should be free of distortion in shape and motion. They should overlap the buckle frame and move freely back and forth in their socket. Roller should turn freely on frame. Check for distortion or sharp edges.
Friction and mating buckles – Inspect the buckle for distortion. The outer bars and centre bars must be straight. Pay special attention to corners and attachment points at the centre bar.
Quick-connect buckles – Inspect the buckle for distortion. The outer bars and centre bars must be straight. Make sure dual-tab release mechanism is free of debris and engages properly. When inspecting lanyards, begin at one end and work to the opposite end, slowly rotating the lanyard so that the entire circumference is checked.
Additionally, follow the procedures below.
Hardware snaps – Inspect closely for hook and eye distortions, cracks, corrosion, or pitted surfaces. The keeper (latch) should sit into the nose without binding and should not be distorted or obstructed. The keeper spring should exert sufficient force to firmly close the keeper. Keeper locks must prevent the keeper from opening when the keeper closes.
Thimbles – The thimble must be firmly seated in the eye of the splice, and the splice should have no loose or cut strands. The edges of the thimble must be free of sharp edges, distortion, or cracks.
The lanyard inspection varies as follows.
Wire rope lanyard – While rotating the wire rope lanyard, watch for cuts, frayed areas, or unusual wearing patterns on the wire. Broken strands will separate from the body of the lanyard.
Web lanyard – While bending webbing over a pipe or mandrel, observe each side of the webbed lanyard. This will reveal any cuts or breaks. Swelling, discolouration, cracks and charring are obvious signs of chemical or heat damage. Observe closely for any breaks in stitching.
Rope lanyard – Rotate the rope lanyard while inspecting from end-to-end for any fuzzy, worn, broken or cut fibres. Weakened areas from extreme loads will appear as a noticeable change in original diameter.
Energy-absorber pack – The outer portion of the pack should be examined for burn holes and tears. Stitching on areas where the pack is sewn to D-rings, belts or lanyards should be examined for loose strands, rips and deterioration.
Understanding Suspension Trauma
Suspension trauma happens when a fallen worker is suspended in a harness with legs hanging. While arteries near the fronts of the legs continue pumping blood, the harness straps act like tourniquets on the veins in the backs of the legs and prevent used (deoxygenated) blood returning to the heart.
If circulation is impeded enough, the heart rate will abruptly slow and reduce oxygen to the brain. Even under ideal circumstances, with a rescue plan in place, suspension trauma must be treated as an emergency. It can be fatal in as little as 10 minutes. Typically, suspension trauma causes death in 15 to 40 minutes.
Suspension trauma is caused by orthostatic incompetence (also known as orthostatic intolerance). Orthostatic intolerance can occur in many different situations, including for workers who have to stand for prolonged periods of time. The legs become immobile with the worker standing in an upright position, allowing gravity to pull blood into the lower legs. While in a sedentary position, blood can accumulate in the veins – commonly referred to as venous pooling—and cause orthostatic intolerance.
After enough blood accumulates, return blood-flow to the heart is greatly reduced. The heart eventually has to speed up to maintain sufficient blood flow to the brain. But, if the blood supply is restricted enough, the heart is unable to speed up. The reduced heart rate actually causes workers to faint.
“the best way to slow progression of suspension trauma is to stand”
In some cases, that solves the problem because the worker is able to slump to the ground where the legs, heart, and brain are on the same level. Once blood returns to the heart, the worker typically recovers quickly. When wearing a harness, however, workers are suspended and can’t fall to the ground in a horizontal position, which causes the brain’s blood supply to drop critically.
In suspension trauma, several conditions occur: the worker is suspended in an upright position with his or her legs dangling; the safety harness straps exert pressure on arteries in the inner leg, which greatly reduces blood-flow to the heart; and the harness keeps the worker in an upright position, regardless of loss of consciousness, which is how workers often die from suspension trauma. Also, when blood pools and becomes trapped in an extremity, the blood can no longer deliver oxygen from the lungs.
To continue to produce energy to sustain life, the cells in the extremity undergo anaerobic respiration (without oxygen). During anaerobic respiration, glucose breaks down in half into lactic acid in a process known as lactic acidosis. Without blood circulation in the legs, the lactic acid builds up in the stagnant blood. This build-up of acid-blood is then released when the worker is brought down, and circulation restored. High levels of acid flooding the body can overwhelm the kidneys, liver, and even result in heart failure.
Suspension Trauma Rescue
The best way to slow progression of suspension trauma is to stand. When a worker stands, the leg muscles must contract, which puts pressure on the veins. This pressure, along with a series of one-way valves within the veins, helps blood return to the heart and reduces the amount of blood pooling in the legs.
A fallen worker can stand in one of several ways: Suspension trauma relief straps – A fallen worker can deploy trauma relief straps, creating a loop that the worker steps into and presses against to stand up. Relief straps are typically packaged in two pouches that attach to each side of a harness.
Onsite work equipment – The onsite rescue team may be able to bring a ladder, an aerial lift, or other equipment for the suspended worker to stand on.
Structural member – The onsite rescue team may be able to pull the suspended worker over to a structural member, a lower level, or the ground. Everyone who works at heights must be fully trained in fall protection.
Training should include PFAS rescue and first aid/CPR. A specific rescue plan must be developed for each jobsite. The supervisor should assign duties, such as who calls for emergency number and who performs the rescue. The supervisor should evaluate in advance how onsite work equipment could be used. Employers should also provide specialised equipment: suspension trauma relief straps, self-rescue devices, and/or technical rescue equipment for assisted rescue by trained onsite workers. This may include pulley systems, brake-tube systems, winch systems, controlled descent devices, rope ladders, or other devices.
“training should include PFAS rescue and first aid/CPR. A specific rescue plan must be developed for each jobsite”
Whether or not the suspended worker has lost consciousness, the rescue team must be careful in handling the victim. Post-rescue death is caused by the heart’s inability to tolerate the abruptly increased flow of carbon dioxide-saturated blood from the legs. Do not put a rescued worker in a horizontal position – whether conscious or not. If the rescued worker does not have any apparent injuries from the fall, the worker should be placed in a sitting position with knees close to the chest. The position is often called a ‘W’ position. The fall victim should remain in the ‘W’ position for at least 30 minutes to prevent the oxygen-deprived blood returning to the heart suddenly. When Emergency Medical Services (EMS) arrive onsite, ensure that they know to treat the rescued worker for possible suspension trauma. Inform them how long the worker was suspended.
In general, Work at Height related accidents are highly predominant in most of the industries and the consequences are severe which affects the worker life. Both proactive and reactive controls to be taken very intensely to avoid such accidents. Proactive controls like avoiding work at height or as much as possible avoiding human in such activities can be considered. If it is unavoidable, competent persons, trainings and effective fall protection systems can be deployed. As a reactive control, effective emergency rescue procedures and a trained first aid team should be present at the work site. As the International Labour Organization (ILO) states, “Prevention is better than cure”. The workforce should be trained to avoid work at height accidents and to effectively manage emergency scenarios like suspended trauma.