CONSTRUCTION ACTIVITIES – THE PRINCIPAL HAZARDS
While the hazards associated with construction activities are extensive, the principal hazards and their causative factors are outlined below:
Falls from ladders.
Falls are associated with the
use of a ladder at an incorrectpitch, resulting in the ladder slipping out at the base or falling away at the top.
The ‘1 Out: 4 Up Rule’ should always be applied in assessing the correct pitch of a ladder.
Falls can further arise from the use of defective wooden and metal ladders and as a result of overreaching situations.
Falls from working platforms.
Unfenced or inadequately fenced working platforms, inadequate and defective boarding to working platforms and the absence of toe boards are contributory factors in falls of people from working platforms.
Falls of materials.
Small objects, such as bricks, tiles and hammers, dropped from a height can cause fatal head injuries and other forms of serious injury to people below, including members of the public. This can arise through poor standards of housekeeping on working platforms, the absence of toe boards and barriers, incorrect assembly of gin wheel hoists for raising and lowering materials, incorrect or careless hooking and slinging of loads, the failure to install catching platforms (fans) and through demolition materials being thrown to the ground.
Falls from pitched roofs or through fragile roofs.
This is, perhaps, the most common type of fatal accident associated with the construction industry and with those involved in the maintenance of buildings. These falls arise from unsafe
working practices at heights and on roofs, the use of inappropriate footwear, the failure to provide verge and eaves protection and to use crawl boards on pitched roofs, together with the stacking of roofing materials on fragile roofs.
Falls through openings in flat roofs and floors.
This type of accident arises due to the failure to provide or replace covers to openings or edge protection at openings in flat roofs and floors during various stages of construction. All covers should be clearly marked to indicate the presence of an opening below that cover.
Collapses of excavations.
Asphyxiation and fatal injury arising from the collapse of a trench or excavation commonly arise through a failure to support adequately a trench or excavation and in shifting sand situations. The presence of large quantities of water arising, perhaps, as a result of a flash flood or water main bursting may also be a contributory factor in the collapse. Other causes of, particularly, trench collapses include the practice of stacking building materials, such as pallet loads of bricks, heavy concrete sewer pipe sections and heaps of sand too close to the edge of a deep open trench. The failure to reinstate trench timbering or supports following an inspection by a competent person has also been indicated as a cause of trench collapses.
Transport Accidents.
Injuries arising from people falling from vehicles, some of which may not be designed for carrying passengers, such as dumper trucks, are common. Other accidents involving transport on site include crushing by reversing vehicles where no banksman is in operation, collision with defective vehicles owing to inadequate maintenance of, for example, brakes and reversing systems, the operation of vehicles and machinery, particularly lifting appliances, by inexperienced and untrained people and overloading of passenger-carrying vehicles. In particular, poor standards of driving on-site roads contribute greatly to death and major injuries sustained by employees and members of the public. Site roads should be well maintained and drained, kept free from mud and debris as far as possible, and marked out.
Use of machinery and powered hand tools.
Failure to guard adequately moving and dangerous parts of machinery, such as power take-offs, woodworking machinery, belt drives and cooling fans, results in a wide range of major injuries. The use of powered hand tools with rotating heads, such as angle grinders,
and the use of defective and uninsulated electric tools commonly result in a range of injuries from amputations of fingers to electrocution.
Housekeeping.
Standards of housekeeping on construction sites vary greatly. Slips, trips, and falls, resulting in a range of injuries, are common. Site management should ensure a good standard of housekeeping at all times, including provisions for the storage of waste materials prior to removal.
Fire.
Inadequate fire protection measures, commonly associated with poor standards of site supervision, contribute greatly to the risk of fire. Uncontrolled ‘hot work’ activities, such as welding, may create ignition sources together with the burning of site refuse. Well-established fire safety procedures, including regular fire drills, are an essential feature of site safety.
Personal protective equipment (PPE).
Failure on the part of employers to provide, and of employees to use or wear, PPE can be a contributory factor in many of the major injuries sustained by construction workers.
Employers should have a clear policy on the provision and use of PPE based on the requirements of the Personal Protective Equipment Regulations 1992, including the undertaking of PPE risk assessments and selection of suitable PPE.
Work over water and transport across the water.
Construction work on bridges, involving work over water, exposes construction employees to the risk of drowning. In these cases, safety harnesses should be provided and used at all times. Transport over water to a particular workplace, such as a caisson, further exposes employees to the risk of drowning. This may be caused by the overcrowding of boats, defective and inadequate boats and the failure to provide barriers, life jackets or buoyancy aids and other forms of rescue equipment.
Work involving hazardous substances.
Construction workers come into contact with a wide range of hazardous substances, including lead, asbestos and chemical compounds. Failure to prevent or control adequately exposure to these substances linked with poor standards of personal hygiene can lead to chemical poisonings, dermatitis and, in some cases, asbestosis. Inhalation of hazardous dust, such as cement dust, and those arising during demolition, due to a failure to use appropriate respiratory protection, can result in a range of respiratory disorders.
Employers are required to comply with the COSHH Regulations in this case, which includes their undertaking health risk assessments in respect of identified substances hazardous to health, to undertake air monitoring, for example, in the case of exposure to dust, and to provide health surveillance of employees where appropriate. employees may be exposed to lead in its various forms.
This may entail air monitoring and the provision of appropriate control measures to prevent inhalation of lead fumes in particular. Many older buildings still contain asbestos in its various forms. In some cases, asbestos may be present in buildings scheduled for demolition. Here the Control
of Asbestos at Work Regulations must be complied with, including the sampling of asbestos to ascertain the form of asbestos, such as blue asbestos (crocidolite), the procedures for stripping the asbestos (wet or dry stripping), air monitoring requirements and, in particular, the selection, provision and use of respiratory protective equipment. A pre-demolition survey of a building should identify the presence of asbestos.
Manual handling operations.
Manual handling injuries, such as prolapsed intervertebral discs and hernias, are common in the construction industry, arising from incorrect handling techniques and attempting to lift loads which are too heavy. This may arise from the failure to provide and/or use mechanical handling aids, such as hand trucks, barrows and lifting appliances.
Employers are required to comply with the Manual Handling Operations. Regulations with respect to the undertaking of manual handling risk assessments in cases where mechanical handling aids cannot be used. Employees should receive information, instruction, and training incorrect manual handling techniques, supported by constant supervision of their manual handling activities.
Work on underground services.
Damage to underground electricity, gas and water mains can arise during the excavation of an existing site. This may be due to the absence, in many cases, of the plans of the site or the failure to consult existing site plans prior to work commencing. Cable and service locators should be used to identify existing service lines, and test holes should be made with a view to identifying drains and sewers. Unsafe digging and excavating has led to the electrocution of workers in the past, falls into underground spaces and the risk of flooding.
Work in confined spaces.
A ‘confined space’ is defined in the Confined Spaces
Regulations 1997 as a place which is substantial, though not always entirely, enclosed and where there is a risk that anyone who may enter the space could be:
(a) injured due to fire or explosion;
(b) overcome by gases, fumes, vapour or the lack of oxygen;
(c) drowned;
(d) buried under free-flowing solids, such as grain; or
(e) overcome due to high temperature.
Some confined spaces, such as closed tanks and vessels, open-topped tanks, silos and wells, are readily identifiable. However, construction operations may entail work in deep trenches and underground rooms where the risks may be less obvious.
Work in confined spaces exposes operators to the risk, in particular, of both asphyxiation and anoxia (oxygen deficiency), which may be due to the absence of adequate ventilation in these spaces.
Any work of this type must comply with the requirements of the regulations.
Under the regulations employers must:
(a) avoid entry to confined spaces, for example by doing the work from outside;
(b) ensure employees follow a safe system of work, such as a permit-to-work system, if entry to a confined space is unavoidable; and
(c) put in place emergency arrangements before work starts, which will also safeguard any rescuers involved.
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