Excavation Work 706n1u
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METHOD STATEMENT EXCAVATION WORKS
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PURPOSE:
This method statement provides guidance to prevent injury to persons engaged in excavation works on the RAS LAFFAN C IWPP/QATAR site. 2.0
SCOPE: Planning, preparation conduct and Method of excavation work.
3.0
PLANNING AND PREPARATION:
3.1
CONSULTATION
The principal contractor, the contractor doing the work, employers, employees and their representatives will consult with each and determine the provision of all safeguards. The consultation process will be used during the planning and preparation stages to determine safe systems of work based on the assessment of the risks. Structural or geotechnical engineers will be involved in the consultation process when appropriate. The consultation process will at least cover the following: (a) Nature and condition of the ground or working environment. (b)Nature of the work and other activities that may affect safety (c) Static and dynamic loads near excavation (d)Interaction with other trades (e) Workplace access (f) Management of surrounding vehicular traffic and ground vibration (g) Work force safety
(h)Type of equipment used for excavation (i) The provision of appropriate amenities, which will depend on the type of work space. (j) Compliance with all RLC/ HSE regulations
3.2
PLANNING
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Planning and preparation will be the first essential step in ensuring that work is done safely. Planning and preparation will involve consultation with all relevant persons engaged in the work and will include hazard identification, risk assessment and risk control processes. Where appropriate, the advice of a geotechnical engineer will be sought before starting excavation work. The principal contractor and the contractor in their capacity as employers will: 1. Provide such information, instruction, training and supervision as may be necessary to ensure the health and safety of his employees; and 2. Provide or maintain means of access to and egress from the work place safe and without risks. 3.3
PLANNING BY PRINCIPAL CONTRACTOR
The principal contractor will plan for the work to be done safely. The principal contractor will ensure that a site specific occupational health and safety management plan is prepared and documented for each place of work where excavation is to be carried out, before the excavation work commences. This plan will be developed in consultations undertaken with the contractor/s and their employees or representatives. The plan will include a documented work method statement, provided by the contractor, describing how the work is to be done safely. The health and safety management plan will be monitored to ensure that work is carried out according to that plan and that the plan is effective. The plan will be maintained and up to date during the course of the excavation works. Before excavation work starts, the principal contractor in consultation with the contractor doing the work will at least consider: (a) An assessment of the risks involved in carrying out the work. (b) the most appropriate method to prevent any risk of injury. (c) An assessment of the ground conditions and working environment (d) Providing suitable and safe access to and from the work place including the work area. (e) The area of the excavation work will be clearly defined by barricades and warning signs. (f) Where necessary the exact location of the work will be clearly marked. (g) The identification and marking of the location of any above ground, underground or overhead services (h) That the work does not affect the structural integrity of ading buildings or structures, roads, footpaths. (i) Electrical safety, including the location of underground and aboveground service cables and nearby overhead power lines and providing systems of work which comply with RLC & RLC/HSE regulations. (j) That all persons carrying out the work will receive appropriate supervision, training and instruction. (k) Security of excavation during work and when left unattended.
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(l) Establishment of emergency and rescue procedures in the event of an emergency. 3.4
PLANNING BY THE CONTRACTOR
The contractor doing the work has an obligation under RLC/HSE regulations to provide and maintain a workplace that is safe and without risks to health for their employees in relation to those matters over which he has control. In addition to consultation with the principal contractor in the overall job planning, the contractor will at least consider: (a) An assessment of the risks in carrying out the work. (b) The most appropriate methods of preventing the risk of injury. (c) Providing a documented safe work method statement describing how the work will be done safely. This safe work method statement will take into an assessment of the risk involved in carrying out the work. (d) Providing suitable and safe access to and from the work area at all times. (e) Preventing persons entering a work area where there is a risk of injury. (f) An assessment of manual handling tasks which could cause back strains and other injuries and providing systems of work which comply with the provisions of RLC/HSE regulations. (g) That the location of overhead and underground services, i.e. electricity and telecommunication cables, are identified and clearly marked. (h) Electrical safety, including the location of underground electrical service cables and nearby overhead power lines and providing systems of work which comply with RLC/HSE regulations (i) The use of personal protective equipment (PPE) Eg: Safety footwear, eye, coveralls, high visibility jackets, hearing protection, safety helmets, gum boots, gloves, disposable clothing etc. (j) That all persons carrying out the work are provided with appropriate training and instruction. (k) That supervision is provided by a competent person. (l) Establishment of emergency and rescue procedures in the event of an emergency. 3.5
HAZARD IDENTIFICATION, RISK ASSESSMENT AND CONTROL
A hazard identification risk assessment and control process will be carried out by the contractor in consultation with the principal contractor to determine if persons are at risk. Safe systems of work will then be put into place to control the risk. The identification of the hazards associated with excavation work, the risk assessment and the risk control measures will be documented. The process of hazard identification, risk assessment and control is made up of the following steps: 1. Identify the hazards.
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2. Assess the risk(s) arising from the hazards. 3. Use appropriate control measures to eliminate or reduce the risk(s). 4. Monitor and review the control measures to ensure continual safety. After identifying the hazards involved in carrying out the work the principal contractor in consultation with the contractor will assess the health and safety risks and determine what type of safeguards or systems of work will be implemented to ensure the health and safety of all persons on site. This will always include eliminating exposure of persons to the hazard. 3.6
HIERARCHY OF CONTROL MEASURES
The following hierarchy of control measures is listed in of levels. selecting the highest level possible to develop each control measure. Level 1: Eliminate the hazard: • For example, choose different Excavation method. Level 2: Minimize the risk by: • substituting the system of work or plant (with something safer). • modifying the system of work or plant (to make it safer). • isolating the hazard (eg. introduce a restrictive work area). • introducing engineering control (eg. dust control). Level 3: Other controls: • adopting istrative controls such as hazard warning signs and specific training and work instructions. • using personal protective equipment (eg. eye, respiratory and hearing protection). The control measures at Level 1 (eliminate the hazard) give the best results and will be adopted. The measures at Levels 2 (minimize the risk) and 3 (other controls) are less effective and they require more frequent reviews of the hazards and systems of work. In some situations a combination of control measures may need to be used. The control measures recommended by the contractor will be considered by the principal contractor as part of the health and safety management plan. Any new control measures will be evaluated to ensure that they are effective and safe and that new hazards are not created (directly or indirectly) by them. 3.7
PREPARATION
When preparing for the commencement of work the principal contractor and the contractor doing the work will ensure that the workplace is safe based on the health and safety management plan. They will also check to ensure that all
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controls identified by the risk assessment have been put in place and that no new hazards exist. Preparation will also at least include: (a) an assessment of climatic/environmental conditions. (b) access to and from the workplace. (c) specific instructions for employees. (d) that plant and equipment is suitable for the intended use and inspected by a third party before use and is properly maintained. (f) personal protective equipment. (g) that the location of underground, above ground and overhead services are identified and clearly marked. (h) emergency and rescue procedures in the event of an accident, injury or other emergency, including the means of protect any other persons in the vicinity. 3.8
EMERGENCY AND RESCUE PROCEDURES
The contractor will ensure that, in the event of an emergency, adequate arrangements have been made to ensure the safety of workers and other persons on site. The emergency may result from an accident or injury, landslip or other potentially dangerous occurrence. Natural disaster including electrical storms, floods,plant or machinary fire etc may also present hazards to the working operations. The contractor will plan for such matters and ensure that appropriate control measures are in place. The risk assessment will take into the following factors: (a) nature of hazard and possible emergencies; (b) size and location of place of work; (c) number and mobility of persons at the workplace; and (d) location of nearest emergency services. Control measures may include:
(a) development and communication of a warning system. (b) development and communication of safe and rapid evacuation procedures, including injured persons. (c) having trained personnel to oversee evacuation and rescue procedures until emergency authorities arrive. (d) appropriate medical treatment and evacuation of injured persons. (e) shutting down of work, including plant and electrical equipment. (f) provision of firefighting equipment at appropriate locations.
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EXCAVATION WORKS (g) display of evacuation procedures in appropriate location(s) 4.
WORK SYSTEMS AND CONTROL MEASURES
The principal contractor and contractor have an obligation under RLC/HSE regulations to provide and maintain a workplace that is safe and without risks to health for their employees in relation to those matters over which they have control. Control measures to prevent persons being injured during excavation work will be provided and maintained as part of a safe system of work. The system of work and control measures selected will be determined by individual job factors identified in the consultation and risk assessment process. The following hazards are commonly associated with excavation work and will be considered by the risk assessment process: (a) the fall or dislodgement of earth and rock (b) the instability of the excavation or any ading structure (c) the inrush or seepage of water (d) unplanned with utility services eg, electricity (e) the placement of excavated material (f) falls into excavations (g) the movement and positioning of heavy plant and equipment affecting the excavation (h) ground vibration affecting the stability of the excavation (i) vehicle movement (j) excessive noise from the operation of machinery and plant (k) manual handling injuries (l) changes to excavation conditions. 4.1 PREVENTION OF COLLAPSE OR FAILURE OF TRENCHES AND OPEN EXCAVATIONS A risk assessment will be conducted to determine which controls will be implemented to prevent persons being injured by collapse or failure of all or part of a trench or open excavation. It will consider at least the following: (a) the depth of the excavation; (b) the nature of the strata - sand, clay, shale, floaters, etc including their likely behavior upon exposure to the elements; (c) fractures or faults in rock. (d) the presence of moisture or water; (e) the possibility of exposure to wet weather and water from other sources; (f) any load close to the edge or in the zone of influence of the excavation; (g) vibration; (h) the exposure time;
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(i) any previous disturbance of the ground, eg previous excavations; and (j) ading buildings or structures Removal of soil from an excavation causes unbalanced soil stresses which reduce the capacity of the excavation to itself. There may be additional geotechnical engineering issues that will be considered. Accordingly where the risk assessment identifies the risk of an unstable condition, the following measures will be considered before starting excavation work: (a) seeking advice from appropriately qualified engineers, (b) carrying out a geotechnical analysis, (c) engaging a competent person to supervise the progress of the excavation work. Shoring systems, benching and battering are engineering issues that involve both structural design and soil mechanics. The use of adequate shoring, benching and battering is essential to control the risk of a collapse or failure of a trench or open excavation. 4.2
DESIGN OF ENGINEERING CONTROLS
Design specifications for engineering controls such as shoring structures, benching or battering will be prepared by an appropriately qualified person in accordance with relevant standards and codes. In developing specifications, at least the following factors will be considered: (a) the size and strength of the component of the shoring (b) existing and changing ground conditions (c) the loads and types of ground or soil conditions to be shored (d) static loads near excavation, eg. spoil pile, buildings and structures (e) dynamic loads near excavation, eg. traffic and excavation equipment (f) ground vibration, eg. heavy traffic, mobile plant, and pile driving. (g) difficulties or risks that other services may pose ie overhead power lines, existing or proposed underground services (h) working environment such as exposure to dust, noise, water, (i) that systems of work are in accordance with any requirements of the RLC/HSE regulations (j) location of utility services (k) safety during installation and removal. 4.3
SHORING
Where necessary, all trenches and excavations will be adequately shored or ed to prevent a fall or dislodgement of earth, rock or other material forming the side of or adjacent to, any excavation work from burying, trapping or striking a person that is in the excavation. Where such a risk also exists for those installing s, other appropriate control measures will be in place to
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EXCAVATION WORKS
ensure the safety of persons entering the excavation. A shoring system will not be required if, having regard to the nature and slope of the side of the excavation and other relevant circumstances there is no reasonable likelihood that earth, rocks other material will fall or dislodge from a height of more than1.5m and bury, trap or strike a person that is in the excavation. The risk assessment process will be used to identify unstable conditions and the risks involved. Shoring the face of an excavation will proceed as the work of excavation progresses. Where a mechanical digger is used, the risk assessment will be used to determine whether any part of the trench may be left uned. Shoring may include any suitable system of temporary s and sheeting material used to maintain the stability of the sides of an excavation. The installation and removal of shoring will take place from outside an excavation. 4.3.1
REMOVAL OF SHORING S
When removing shoring, the system will be extracted / dismantled in the reverse order of its installation. Persons performing the work in the excavation will not work outside the protection of the ground system. 4.4
BENCHING AND BATTERING EXCAVATION WALLS
Both benching and battering of excavation walls are methods of work which may be used to minimize the risk of the soil or rock slipping onto the excavation. If battering is implemented, it will commence from the bottom of the excavation. When benching or battering the walls of an excavation, an angle of repose of 45 degrees will not be exceeded unless certified in writing by a geotechnical engineer. 4.5 INSPECTION OF SYSTEMS Where risks or hazards that create a risk to health and safety of those carrying out the work are identified, they will be controlled prior to any further work being carried out. This may require further advice from geotechnical and design engineers to review the adequacy of the control measures in place. The risk assessment will be reviewed at all during the excavation works. The following conditions will be considered or monitored: (a) shoring becoming unstable (b) shoring components not secure or failing (c) angle of batter remains sufficient to prevent collapse (d) premature removal of shoring
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(e) workers in excavations venturing outside the confines of shoring, benching or battering (f) cracks appearing near the edge of an excavation (g) excavated and other material being placed within the zone of influence of the excavation (h) machinery operating within the zone of influence of excavations causing weight and vibration influences (i) surface soil falling into the excavation (j) water seeping into excavations from its side walls or base (k) changes to soil and/or weather conditions (l) extra loading (m)surface water or run-off entering the excavations or accumulating on surface near the excavation (n) inclined bedding planes “dipping” into the excavation (o) heaving or swelling of the ground at the bottom of the trench (p) subsidence alongside the excavations (q) unsafe access or egress (r) exposure of contaminated ground (s) undercutting of the excavation
4.6
SECURITY OF EXCAVATIONS
A risk assessment will be conducted in order to determine which controls will be implemented to ensure the security of excavation both during work and when left unattended. The control measures implemented will be appropriate and effective for the hazards and risks of the situation. Consideration will be given to factors such as how long the excavation will be open, and who may gain access to the excavation. The following control measures will be considered: (a) isolating the hazardous area, such as by the use of perimeter fencing, barricades, screens, barriers, handrails and/or covers, which are capable of preventing access or preventing the fall of a person (b) removal or lowering ladders on work site (c) immobilization of plant to prevent unauthorized use (d) compliance with relevant RLC/HSE requirements. (e) hazard warning lights, signs, markers or flags (f) site security measures, including fencing or use of safety observer(s) (g) night lighting.
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Signs will be erected around the site showing the name and telephone number (including after hours emergency number) of the principal contractor/contractor/RLC emergency numbers. 4.6.1
FALL PREVENTION
A safe system of work and appropriate control measures will be provided wherever persons are exposed to a risk of falling during excavation work. It is a RLC/HSE requirement to effectively fence all excavations and holes more than 1.2m deep. It will also be noted that all platforms, open sides of stairways and stairway landings will be fenced. In addition to the security measures listed above, the following measures to prevent falls will be considered: (a) use of intermediate platforms for deep excavation (b) provision of a safe means of movement between different levels of the excavation (c) provision of an adequate fall arrest system (d) backfilling as work progresses Control measures will be properly installed and maintained until the work is completed or until there is no longer any risk of persons falling into the excavation. 4.6.2
PREVENTION OF DROWNING
Where, during excavation work, and excavation is likely to collect or retain water so as to create a hazard to persons in the vicinity, the excavation will be covered or fenced off. Control measures will be provided where there is a risk of a person drowning as a result of a fall into water or other liquid, eg slurry. The following measures will be considered: (a) provision of positive means of fall protection such as fencing, handrails and safety harness (b) provision of an observer. 4.7
UNDERGROUND SERVICES
Before starting the work, the location of any underground services (eg. electricity, telecommunication cables, etc) will be identified. Wherever service plans are available they will be obtained by the principal contractor and also provided to the contractor and operator carrying out the excavation work. The
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contractor will allow for inaccuracies and the possibility of other unknown or hidden services. Further, the principal contractor will arrange for these services to be clearly marked according to the available plans and on site checks prior to commencement of work. Services will be exposed at sufficient intervals to positively identify their location and/or lie. The following are ways of checking for underground services: (a) using remote location devices (b) hand digging, using hand tools with non-conductive handles. All persons whose work may be affected by an underground service will be advised of the location of every underground service. Appropriate control measures will be implemented after consultation with relevant service providers. These measures may include the protection, or removal of services to ensure safety of workers. 4.8
EXCAVATIONS ADJACENT TO BUILDINGS OR STRUCTURES
The contractor will ensure that excavation work which is likely to reduce the security or stability of any part of any building or structure will not be commenced or continued unless adequate steps are taken before and during the progress of the work to prevent danger to any person from collapse of the building or structure or a part of a building or structure. In assessing the risk, measures such as the following will be considered before starting excavation work: (a) seeking advice from appropriately qualified engineers (b) undertaking a geotechnical analysis (c) engaging a competent person to supervise the progress of the excavation work (d) underpinning of structures (e) construction of effective retaining walls (f) minimizing ground disturbance and vibration by taking into the location of machinery, the sequence of work, the impact, severity and scale of excavation (g) backfilling as work progresses (h) evacuation of affected areas. The contractor will also ensure the stability of vehicular access which might be affected by the work.
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4.9 PROTECTION AGAINST RISING, IRRUPTIONOR INRUSH OF WATER OR MATERIAL The contractor will ensure that where there is risk from rising water or from an eruption of water or material, the means to enable every person to reach a position of safety will be provided. If a risk assessment reveals a risk of rising, irruption or inrush of water or material, appropriate control measures will be provided. These may include the following: (a) provision of exploratory or warning holes where water flows at a reduced rate to warn of danger (b) provision of sumps (c) lowering the water table (eg use of spear pumps) (d) increasing exit points eg increasing the number of exit ladders (e) provision of pumps 4.10 MATERIALS AND LOADS ABOVE AND NEAR EXCAVATIONS To reduce the risk of excavation collapse, excavated or other loose material will be effectively stored or retained away from the excavation. Excavated material will be placed outside the zone of influence. Alternatively the system will be designed to accommodate such additional load including ground water pressures, saturated soil conditions and saturated materials. Mechanical plant, vehicles, storage of materials or any heavy loads will be prevented from approaching within or encroaching on the zone of influence of the excavation unless the system has been specifically designed for such loads. Where the risk assessment has identified a risk of collapse as a result of loads or materials above or near the excavation, shoring will be in place before any person enters the excavated area. The following measures will also be considered before starting excavation work: (a) controlling access to exclude persons from hazardous areas, eg relocating means of access (b) moving and storing loads outside the zone of influence of the excavation (c) provision of wheel stoppers to limit movement of mobile equipment adjacent to the excavation (d) reducing the number of trench shields stored near excavation by pulling along trench shields and backfilling as the excavation progresses
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(e) securing all loose materials in place. When working on a slope, a risk assessment will be conducted to determine the safest side of the excavation to dump soil and excavated material. This will often be on the lower side of the slope to reduce the risk of wall collapse or material falling into the excavation. Site factors will be considered. 4.11
PROTECTION FROM FALLING OBJECTS
The risk assessment will be used to determine appropriate control measures to protect persons from accidental falls of objects including tools, plant and other construction materials. As far as practicable, loads will not be suspended or travel over a person. The following control measures will be considered: (a) fences (b) hand rails and toe boards (c) overhead protection (d) enclosed walkways (e) safety helmets and other adequate means of protection (f) provision of safe means of lowering and raising plant, materials, spoil, etc (g) use of lanyards to secure loose tools (h) loads will be lifted/suspended within the safe working limits of the machinery load used. 4.12
ELECTRICAL HAZARDS
Specific control measures will be implemented when work is done in the vicinity of power lines whether they are overhead or underground. A power line or electrical conductor will always be assumed to be energized or ‘live’, including when a communication cable or wire is encountered. 4.12.1
UNDERGROUND ELECTRICAL HAZARDS
A safe system of work will be devised to address electrical hazards associated with underground services as the following: (a) de-energizing and isolating the cables and obtaining documentary evidence of the continuing isolation of the power supply before proceeding with the work (b) a system of lock out and lock out tags (c) use of electronic surveillance prior to excavation to determine location of services. (d) hand digging using tools with non conductive handles (e) wearing rubber boots and insulating gloves
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OVERHEAD POWER LINES
When cranes, excavators, earthmoving machines or similar appliances are operated near overhead power lines the following provisions will be observed: (a) A thorough examination of the approaches and surroundings of the site will be carried out before taking an appliance to the site or setting it up. 4.13
MANUAL HANDLING
Manual Handling requires engineers and supervisors to design equipment, tasks and work environments so that manual handling risks are eliminated or reduced as far as reasonably practicable. The contractor will assess and control the risks involved in carrying out manual handling tasks. This will be done in consultation with employees who are required to carry out the work. The contractor will control risks by: (a) deg or re-deg the manual handling task to eliminate or control the risk factor. Where re-design is not practicable, the employer will: • provide mechanical aids and/or personal protective equipment. Using powered mechanical equipment to lift and move materials may control manual handling risks. Lifting equipment will include cranes, forklifts. (b) providing appropriate training to employees in safe handling techniques. This training will also include the prevention of manual handling injuries by an approach based on a hazard identification, risk assessment and control through job and task design. Employees will receive appropriate training in methods of manual handling involving team lifting procedures, correct use of the mechanical aids and PPE. (c) weights that are manually handled will be minimized. Furthermore persons will not be required to lift, lower or carry loads above 25kg, unless mechanical assistance and/or team lifting arrangements are provided to lower the risk of injury. (d) where manual handling involves repetitive bending, twisting, over-reaching, work overhead or where persons have pre existing injuries, these loads will be further decreased. Often used items such as tools, etc, will be stored at waist level. Where possible, most commonly used items will be stored between thigh and chest height. (e) the rotation of work duties will be considered in consultation with employees so that employees are not subjected to the same task for the whole shift. (g) ensuring that work areas and ageways are kept clean and clear of debris. Slippery floors and surfaces and trip hazards will be controlled. 4.14
ACCESS
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An assessment of access requirements will take into the number of persons using them and any tools and equipment that they may be required to carry to and from the work site. Control measures may include: (a) proper storage of materials and plant (b) keeping work areas and ageways clear and free of obstructions (c) removal of rubbish, including construction waste and excess excavated material (d) use of handrails (e) traffic and plant controls (f) safety fences and warning signs. 4.14.1
LIGHTING
Adequate lighting (natural or artificial) will be provided to ensure the work areas and access ways are well lit. Adequate local lighting will be provided for detailed work, for dangerous processes and where machinery is being operated. When artificial lighting is used, including lighting for night work, the contractor will ensure it does not create excessive glare or shadows. 4.14.2
RAMPS
When access ramps are provided they will not exceed 1:2.7 (20 degrees). Ramps steeper than 1:8 (7 degrees) will be cleared, grated or have surfaces which allow adequate foot grip. Where such ramps form part of an excavation, a risk assessment will be conducted to determine the maximum safe soil height above the ramp before some sort of soil (eg trench shield) is provided. Ramps will be designed and constructed to effectively withstand any anticipated load that they may be required to during use. 4.14.3
LADDERS
when ladders are used for access the contractor will provide the following: (a) the ladder will be secured at both top and bottom against displacement. Ladders will have non-slip feet and whenever practicable will be set up at an angle of 1:4 (75degrees). (b) a safe and adequately sized landing place when stepping off the ladder will be provided. (c) the stiles of the ladder will extend at least one meter above the landing place. (d) metal or wire reinforced ladders will not be used where there is a risk of with electrical conductor wires(power lines) or of electric shock. Nonconducting ladders will be used or a clearance of at least 4metres from conductors will be maintained.
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SCAFFOLDING
Scaffolding will be used to provide workers with a safe temporary work platform. It will be planned, erected, inspected and tagged by competent persons and will be regularly inspected to ensure there are no risks to safety and will comply with the requirements of RLC/HSE regulations. . 4.14.5
FIXED PLATFORMS, WALKWAYS, STAIRWAYS AND LADDERS
Fixed platforms, walkways, stairways and ladders will comply with the requirements of RLC/HSE regulations 4.15 WORKS NEAR TRAFFIC OR MOVING PLANT . Planning and preparation will also include the development of a vehicle movement procedure for each worksite. Vehicle movement procedures will identify the preferred travel paths for vehicles associated with a work site entering, leaving or crossing the through traffic stream. A vehicle movement procedure will include persons, moving equipment, plant and vehicle traffic in the work area and also identify travel paths for trucks at key points on routes remote from the work site, such as places to turn around, accesses, ramps and side roads. A vehicle movement procedure will be a documented procedure, a diagram, combined with or superimposed on a Traffic Control Plan, or may be verbal information and instructions specific to the particular construction workplace or site. The risk management process will be used to determine which is the most appropriate. A risk assessment will be conducted to determine what type of safeguards or systems of work that be implemented on the site and will include eliminating exposure of persons to moving plant. Vehicle movement procedures will be developed based on the risk assessment and will be developed each time the conditions on the site change in a way that may affect the health and safety of persons. The risk assessment will consider at least the following: (a) isolating vehicles and plant used in or around the site and work area from persons on the site or work area, eg. vehicles or persons may be guided around or past the work area. (b) securing the area where moving plant is being used eg. fencing, barriers, barricades, temporary warning or control signs or a combination. (c) planning the direction that the plant moves so that the visibility of operators is not restricted. This will also include an assessment of the visibility of plant and traffic from all areas of the work site. (d) the use of spotters/safety observers to control traffic movement (e) implementing safe working distances
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(f) the use of audible reversing alarms and/or other technologies or other safe work practices. Note: reversing alarms may cause confusion where multiple plant is using the same area and other systems of work may be required. (g) minimizing the number of moving plant working at one time. Where multiple plant is being operated around the work site a competent person will be used to direct the plant: • when operating in close proximity to each other; • when reversing; • where persons are on the ground; and • in other situations as indicated by the risk assessment. (i) where construction vehicles or plant enter or leave the work area by public roads, systems of control and notices will be placed at all entrances and exits to the work area to protect and warn all persons approaching or in the vicinity (j) where plant is being operated near persons, near underground or above ground services (any other workers, soils technicians, surveyors, visitors etc) (k) designated delivery and turning areas. The movement of delivery vehicles on construction sites frequently presents a hazard particularly when reversing, loading and unloading. Procedures will be implemented to warn all persons affected by the potential hazard. These procedures will include: • the requirement for truck drivers to report to a suitably signposted area on the site; • the requirement for a designated worker to act as an observer to ensure all persons are clear of the reversing vehicle; and • a system of communication and warning to persons near delivery point. All personnel on site will wear high visibility garments. 4.16
NOISE
Noise management provisions will be carried out by the contractor doing the work and will ensure noise levels from machinery or equipment being used do not become a risk to hearing or health. An appropriately qualified person will conduct a noise assessment to determine the level of noise that employees are exposed to. Where the noise is in excess of the noise exposure limits, engineering controls will be implemented. Where this cannot be achieved or work cannot be organized to minimize exposure, appropriate hearing protection equipment, hearing protectors, will be provided to all persons in the vicinity of the noise. The contractor will also ensure compliance with RLC Environmental Protection requirements in relation to noise.
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The contractors will ensure that all necessary prevention or protection measures are taken to ensure the health and safety of persons who may be exposed to excavated material. Where there is a risk of inhalation of harmful airborne substances such as silica dust or with harmful soil contaminants, the contractor will ensure a safe system of work. The risk assessment process will be used to determine the engineering controls, work practices and site, atmospheric monitoring required. Appropriate assessment of the exposure levels will be undertaken before selecting the control measures. The assessments will consider: (a) any persons on site, including other contractors or persons working on the site; (b) persons conducting the assessment and site remediation, including subcontract workers; (c) visitors to the site (for example, couriers); and (d) site neighbors (as appropriate). The contractor will also ensure that exposure to nonhazardous substances such as nuisance dust is at a level not greater than that established by safe exposure standards. In dry conditions, frequent watering, where practicable, or other similar methods will be used to reduce nuisance dust that will not exceed 20mg/m3. TABLE 1: TRENCHES
GASES COMMONLY FOUND IN EXCAVATIONS AND
Gases or fumes found ground Carbon dioxide, hydrogen sulfide ground
TABLE 2:
TOXIC, FLAMMABLE AND ASPHYXIATE GASES
Type of
Filled and made
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Flammable
Hydrogen Sulfide Carbon dioxide Employers will implement a suitable system of work so as to ensure a safe repairable atmosphere and effective ventilation and will protect persons against the effects of insufficient oxygen. These may be encountered when carrying out work such as excavations for foundations, in addition to trenches. Where the risk assessment indicates the possibility of air contamination, the work will be examined by competent persons using appropriate detecting equipment and will include air testing for: (a) oxygen deficiency (b) airborne contaminants
5.
INSPECTION AND MAINTENANCE OF PLANT AND EQUIPMENT
A risk assessment will be conducted before operating plant to identify any hazards that may arise and the control measures to be implemented. The risk assessment will consider at least the following: (a) that appropriate guards, including roll-over protective devices (ROPS) are fitted (b) that the safe working load is displayed (c) record of testing, maintenance, servicing and repair (d) the general mechanical/electrical condition of plant, especially any wear or damage that may affect safe operation (e) specific controls to prevent entanglement or workers being trapped between moving parts. All plant such as excavators, tractors, etc used for lifting will have their safe working loads displayed and maintained. If the function or condition of plant represents an immediate risk to health and safety, operation will cease and the plant will be withdrawn from use until a risk assessment and appropriate control measures are implemented.
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ROUTINE INSPECTION
Regular planned inspection and adequate maintenance will be carried out to ensure safe operation of all plant used on excavation work, whether leased, hired or owned. Both mechanical and electrical testing will be done. The following checks will also be carried out: (a) Daily checks: general condition and maintenance of the plant will be checked daily by the person doing the excavation work. (b) Regular checks: the plant will be inspected by a competent person on a regular basis, or at least every two weeks. 5.2
REPAIRS AND MAINTENANCE
The contractor will ensure the plant repairs will be carried out by a competent person and in accordance with the designer’s or manufacturer’s requirements. 5.3
REPORTING DEFECTS
Any defects to equipment will be reported immediately to the person responsible for maintaining such plant. Where a defect is likely to pose an immediate risk to health and safety the equipment or plant will not be used until the defect is rectified. 5.4
LOG BOOKS AND INSPECTION CHECK SHEETS
The contractor will keep logbooks and inspection check sheets containing a full service and repairs history of the equipment.
6.
TRAINING AND INSTRUCTION
Under RLC/HSE regulations employers will provide training, instruction, information and supervision, as may be necessary, to ensure the health and safety at work of their employees. This will be provided by a competent person. All persons involved in any excavation or associated work will: • be trained to follow systems of work and work practices that enable them to perform their work in a manner that is safe and without risks to health, and; • hold appropriate certificates of competencies where required, particularly in the operation and use of load shifting equipment. Only persons who have received training and instruction will carry out the work. The training provided and the instruction given will at least include:
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(a) induction training which complies with Construction Safety & RLC/HSE regulation (b) the work method to be used for the excavation or associated work and the manual handling procedures for the work to be carried out, including control measures based on the risk assessment to prevent injury. (c) the correct use, care and storage in accordance with the manufacturer’s recommendations where appropriate, of: • personal protective equipment; and • tools and equipment to be used. (d) the use of plant and associated equipment, including electrical safety and hazardous substances. (e) procedures to be adopted in the event of accident, injury or other emergency, including evacuation. 7.
PERSONAL PROTECTIVE EQUIPMENT(PPE)
The use of PPE to control hazards and risks is the least effective measure and is lowest on the hierarchy of control measures. Control measures will be selected from the highest level possible and be adopted where practicable. The measures at the lower levels are less effective and they require more frequent reviews of the hazards and systems of work. They will only be used when other control measures are impracticable or when, after implementing other controls, a residual risk remains. 7.1
PROVISION OF PPE
Before commencing any work, the principal contractor and or contractors will identify any conditions likely to affect the health and safety of persons. If other means of control are not practical, the provision and use of appropriate PPE that complies with the relevant RLC/HSE regulations will be arranged. Employees will be trained till they are competent in the proper selection, use and maintenance of the PPE. There will be sufficient supervision and monitoring conducted to ensure compliance. 7.1.1
SAFETY HELMETS
The use of safety helmets may prevent or lessen a head injury from falling objects or a person hitting their head against something. Where there is a likelihood of persons being injured by falling objects and overhead protection is not provided, persons will be provided with and will use an appropriate safety helmet. Appropriate safety helmets will also be provided and used where a person may strike their hand against a fixed or protruding object or where there is a risk of accidental head with electrical hazards.
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All persons on excavation sites will wear head protection that conforms to Occupational protective helmets. 7.1.2
EYE PROTECTION
Eye protection complying with RLC/HSE regulations will also be provided, where there is a risk of eye injury. Selection, use and management systems will comply with RLC/HSE regulations 7.1.3
PERSONAL HEARING PROTECTION
A noise assessment will be conducted to determine the level of noise that employees are exposed to. Where the noise is in excess of the noise exposure limits, engineering controls will be implemented. 7.1.4
HIGH VISIBILITY GARMENTS/SAFETY REFLECTIVE VESTS
Persons working near traffic, mobile plant or equipment under operator control, will be provided with and use high visibility garments. Other clothing not covered by the high visibility garment will be light colored and all garments will be selected for best contrast with the surrounding background. 7.1.5
SAFETY GLOVES
Where there is a risk of hand injury hand protection that complies with RLC/HSE regulations will be provided and used. 7.2
MAINTENANCE AND USE OF PPE
The contractor will provide such information, instruction, training and supervision as may be necessary to ensure that PPE are used and maintained as intended. All PPE used by persons during excavation work will be regularly inspected and replaced as necessary. 8.
OCCUPATIONAL HEALTH AND SAFETY
While the obligation for each person is different, all persons will ensure that the way they carry out their work will not interfere with the health and safety of the other persons who are present at the workplace. All work practices must comply with RLC/HSE regulations. CONTRACTOR’S RESPONSIBILITIES The contractor has an obligation to take reasonable care for the health and safety of the other persons in the place of work and to cooperate with their
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employer in the interests of health, safety and welfare. Employees will use appropriate protective equipment for the work being performed.
1.0
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PURPOSE:
This method statement provides guidance to prevent injury to persons engaged in excavation works on the RAS LAFFAN C IWPP/QATAR site. 2.0
SCOPE: Planning, preparation conduct and Method of excavation work.
3.0
PLANNING AND PREPARATION:
3.1
CONSULTATION
The principal contractor, the contractor doing the work, employers, employees and their representatives will consult with each and determine the provision of all safeguards. The consultation process will be used during the planning and preparation stages to determine safe systems of work based on the assessment of the risks. Structural or geotechnical engineers will be involved in the consultation process when appropriate. The consultation process will at least cover the following: (a) Nature and condition of the ground or working environment. (b)Nature of the work and other activities that may affect safety (c) Static and dynamic loads near excavation (d)Interaction with other trades (e) Workplace access (f) Management of surrounding vehicular traffic and ground vibration (g) Work force safety
(h)Type of equipment used for excavation (i) The provision of appropriate amenities, which will depend on the type of work space. (j) Compliance with all RLC/ HSE regulations
3.2
PLANNING
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Planning and preparation will be the first essential step in ensuring that work is done safely. Planning and preparation will involve consultation with all relevant persons engaged in the work and will include hazard identification, risk assessment and risk control processes. Where appropriate, the advice of a geotechnical engineer will be sought before starting excavation work. The principal contractor and the contractor in their capacity as employers will: 1. Provide such information, instruction, training and supervision as may be necessary to ensure the health and safety of his employees; and 2. Provide or maintain means of access to and egress from the work place safe and without risks. 3.3
PLANNING BY PRINCIPAL CONTRACTOR
The principal contractor will plan for the work to be done safely. The principal contractor will ensure that a site specific occupational health and safety management plan is prepared and documented for each place of work where excavation is to be carried out, before the excavation work commences. This plan will be developed in consultations undertaken with the contractor/s and their employees or representatives. The plan will include a documented work method statement, provided by the contractor, describing how the work is to be done safely. The health and safety management plan will be monitored to ensure that work is carried out according to that plan and that the plan is effective. The plan will be maintained and up to date during the course of the excavation works. Before excavation work starts, the principal contractor in consultation with the contractor doing the work will at least consider: (a) An assessment of the risks involved in carrying out the work. (b) the most appropriate method to prevent any risk of injury. (c) An assessment of the ground conditions and working environment (d) Providing suitable and safe access to and from the work place including the work area. (e) The area of the excavation work will be clearly defined by barricades and warning signs. (f) Where necessary the exact location of the work will be clearly marked. (g) The identification and marking of the location of any above ground, underground or overhead services (h) That the work does not affect the structural integrity of ading buildings or structures, roads, footpaths. (i) Electrical safety, including the location of underground and aboveground service cables and nearby overhead power lines and providing systems of work which comply with RLC & RLC/HSE regulations. (j) That all persons carrying out the work will receive appropriate supervision, training and instruction. (k) Security of excavation during work and when left unattended.
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(l) Establishment of emergency and rescue procedures in the event of an emergency. 3.4
PLANNING BY THE CONTRACTOR
The contractor doing the work has an obligation under RLC/HSE regulations to provide and maintain a workplace that is safe and without risks to health for their employees in relation to those matters over which he has control. In addition to consultation with the principal contractor in the overall job planning, the contractor will at least consider: (a) An assessment of the risks in carrying out the work. (b) The most appropriate methods of preventing the risk of injury. (c) Providing a documented safe work method statement describing how the work will be done safely. This safe work method statement will take into an assessment of the risk involved in carrying out the work. (d) Providing suitable and safe access to and from the work area at all times. (e) Preventing persons entering a work area where there is a risk of injury. (f) An assessment of manual handling tasks which could cause back strains and other injuries and providing systems of work which comply with the provisions of RLC/HSE regulations. (g) That the location of overhead and underground services, i.e. electricity and telecommunication cables, are identified and clearly marked. (h) Electrical safety, including the location of underground electrical service cables and nearby overhead power lines and providing systems of work which comply with RLC/HSE regulations (i) The use of personal protective equipment (PPE) Eg: Safety footwear, eye, coveralls, high visibility jackets, hearing protection, safety helmets, gum boots, gloves, disposable clothing etc. (j) That all persons carrying out the work are provided with appropriate training and instruction. (k) That supervision is provided by a competent person. (l) Establishment of emergency and rescue procedures in the event of an emergency. 3.5
HAZARD IDENTIFICATION, RISK ASSESSMENT AND CONTROL
A hazard identification risk assessment and control process will be carried out by the contractor in consultation with the principal contractor to determine if persons are at risk. Safe systems of work will then be put into place to control the risk. The identification of the hazards associated with excavation work, the risk assessment and the risk control measures will be documented. The process of hazard identification, risk assessment and control is made up of the following steps: 1. Identify the hazards.
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2. Assess the risk(s) arising from the hazards. 3. Use appropriate control measures to eliminate or reduce the risk(s). 4. Monitor and review the control measures to ensure continual safety. After identifying the hazards involved in carrying out the work the principal contractor in consultation with the contractor will assess the health and safety risks and determine what type of safeguards or systems of work will be implemented to ensure the health and safety of all persons on site. This will always include eliminating exposure of persons to the hazard. 3.6
HIERARCHY OF CONTROL MEASURES
The following hierarchy of control measures is listed in of levels. selecting the highest level possible to develop each control measure. Level 1: Eliminate the hazard: • For example, choose different Excavation method. Level 2: Minimize the risk by: • substituting the system of work or plant (with something safer). • modifying the system of work or plant (to make it safer). • isolating the hazard (eg. introduce a restrictive work area). • introducing engineering control (eg. dust control). Level 3: Other controls: • adopting istrative controls such as hazard warning signs and specific training and work instructions. • using personal protective equipment (eg. eye, respiratory and hearing protection). The control measures at Level 1 (eliminate the hazard) give the best results and will be adopted. The measures at Levels 2 (minimize the risk) and 3 (other controls) are less effective and they require more frequent reviews of the hazards and systems of work. In some situations a combination of control measures may need to be used. The control measures recommended by the contractor will be considered by the principal contractor as part of the health and safety management plan. Any new control measures will be evaluated to ensure that they are effective and safe and that new hazards are not created (directly or indirectly) by them. 3.7
PREPARATION
When preparing for the commencement of work the principal contractor and the contractor doing the work will ensure that the workplace is safe based on the health and safety management plan. They will also check to ensure that all
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controls identified by the risk assessment have been put in place and that no new hazards exist. Preparation will also at least include: (a) an assessment of climatic/environmental conditions. (b) access to and from the workplace. (c) specific instructions for employees. (d) that plant and equipment is suitable for the intended use and inspected by a third party before use and is properly maintained. (f) personal protective equipment. (g) that the location of underground, above ground and overhead services are identified and clearly marked. (h) emergency and rescue procedures in the event of an accident, injury or other emergency, including the means of protect any other persons in the vicinity. 3.8
EMERGENCY AND RESCUE PROCEDURES
The contractor will ensure that, in the event of an emergency, adequate arrangements have been made to ensure the safety of workers and other persons on site. The emergency may result from an accident or injury, landslip or other potentially dangerous occurrence. Natural disaster including electrical storms, floods,plant or machinary fire etc may also present hazards to the working operations. The contractor will plan for such matters and ensure that appropriate control measures are in place. The risk assessment will take into the following factors: (a) nature of hazard and possible emergencies; (b) size and location of place of work; (c) number and mobility of persons at the workplace; and (d) location of nearest emergency services. Control measures may include:
(a) development and communication of a warning system. (b) development and communication of safe and rapid evacuation procedures, including injured persons. (c) having trained personnel to oversee evacuation and rescue procedures until emergency authorities arrive. (d) appropriate medical treatment and evacuation of injured persons. (e) shutting down of work, including plant and electrical equipment. (f) provision of firefighting equipment at appropriate locations.
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EXCAVATION WORKS (g) display of evacuation procedures in appropriate location(s) 4.
WORK SYSTEMS AND CONTROL MEASURES
The principal contractor and contractor have an obligation under RLC/HSE regulations to provide and maintain a workplace that is safe and without risks to health for their employees in relation to those matters over which they have control. Control measures to prevent persons being injured during excavation work will be provided and maintained as part of a safe system of work. The system of work and control measures selected will be determined by individual job factors identified in the consultation and risk assessment process. The following hazards are commonly associated with excavation work and will be considered by the risk assessment process: (a) the fall or dislodgement of earth and rock (b) the instability of the excavation or any ading structure (c) the inrush or seepage of water (d) unplanned with utility services eg, electricity (e) the placement of excavated material (f) falls into excavations (g) the movement and positioning of heavy plant and equipment affecting the excavation (h) ground vibration affecting the stability of the excavation (i) vehicle movement (j) excessive noise from the operation of machinery and plant (k) manual handling injuries (l) changes to excavation conditions. 4.1 PREVENTION OF COLLAPSE OR FAILURE OF TRENCHES AND OPEN EXCAVATIONS A risk assessment will be conducted to determine which controls will be implemented to prevent persons being injured by collapse or failure of all or part of a trench or open excavation. It will consider at least the following: (a) the depth of the excavation; (b) the nature of the strata - sand, clay, shale, floaters, etc including their likely behavior upon exposure to the elements; (c) fractures or faults in rock. (d) the presence of moisture or water; (e) the possibility of exposure to wet weather and water from other sources; (f) any load close to the edge or in the zone of influence of the excavation; (g) vibration; (h) the exposure time;
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(i) any previous disturbance of the ground, eg previous excavations; and (j) ading buildings or structures Removal of soil from an excavation causes unbalanced soil stresses which reduce the capacity of the excavation to itself. There may be additional geotechnical engineering issues that will be considered. Accordingly where the risk assessment identifies the risk of an unstable condition, the following measures will be considered before starting excavation work: (a) seeking advice from appropriately qualified engineers, (b) carrying out a geotechnical analysis, (c) engaging a competent person to supervise the progress of the excavation work. Shoring systems, benching and battering are engineering issues that involve both structural design and soil mechanics. The use of adequate shoring, benching and battering is essential to control the risk of a collapse or failure of a trench or open excavation. 4.2
DESIGN OF ENGINEERING CONTROLS
Design specifications for engineering controls such as shoring structures, benching or battering will be prepared by an appropriately qualified person in accordance with relevant standards and codes. In developing specifications, at least the following factors will be considered: (a) the size and strength of the component of the shoring (b) existing and changing ground conditions (c) the loads and types of ground or soil conditions to be shored (d) static loads near excavation, eg. spoil pile, buildings and structures (e) dynamic loads near excavation, eg. traffic and excavation equipment (f) ground vibration, eg. heavy traffic, mobile plant, and pile driving. (g) difficulties or risks that other services may pose ie overhead power lines, existing or proposed underground services (h) working environment such as exposure to dust, noise, water, (i) that systems of work are in accordance with any requirements of the RLC/HSE regulations (j) location of utility services (k) safety during installation and removal. 4.3
SHORING
Where necessary, all trenches and excavations will be adequately shored or ed to prevent a fall or dislodgement of earth, rock or other material forming the side of or adjacent to, any excavation work from burying, trapping or striking a person that is in the excavation. Where such a risk also exists for those installing s, other appropriate control measures will be in place to
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ensure the safety of persons entering the excavation. A shoring system will not be required if, having regard to the nature and slope of the side of the excavation and other relevant circumstances there is no reasonable likelihood that earth, rocks other material will fall or dislodge from a height of more than1.5m and bury, trap or strike a person that is in the excavation. The risk assessment process will be used to identify unstable conditions and the risks involved. Shoring the face of an excavation will proceed as the work of excavation progresses. Where a mechanical digger is used, the risk assessment will be used to determine whether any part of the trench may be left uned. Shoring may include any suitable system of temporary s and sheeting material used to maintain the stability of the sides of an excavation. The installation and removal of shoring will take place from outside an excavation. 4.3.1
REMOVAL OF SHORING S
When removing shoring, the system will be extracted / dismantled in the reverse order of its installation. Persons performing the work in the excavation will not work outside the protection of the ground system. 4.4
BENCHING AND BATTERING EXCAVATION WALLS
Both benching and battering of excavation walls are methods of work which may be used to minimize the risk of the soil or rock slipping onto the excavation. If battering is implemented, it will commence from the bottom of the excavation. When benching or battering the walls of an excavation, an angle of repose of 45 degrees will not be exceeded unless certified in writing by a geotechnical engineer. 4.5 INSPECTION OF SYSTEMS Where risks or hazards that create a risk to health and safety of those carrying out the work are identified, they will be controlled prior to any further work being carried out. This may require further advice from geotechnical and design engineers to review the adequacy of the control measures in place. The risk assessment will be reviewed at all during the excavation works. The following conditions will be considered or monitored: (a) shoring becoming unstable (b) shoring components not secure or failing (c) angle of batter remains sufficient to prevent collapse (d) premature removal of shoring
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(e) workers in excavations venturing outside the confines of shoring, benching or battering (f) cracks appearing near the edge of an excavation (g) excavated and other material being placed within the zone of influence of the excavation (h) machinery operating within the zone of influence of excavations causing weight and vibration influences (i) surface soil falling into the excavation (j) water seeping into excavations from its side walls or base (k) changes to soil and/or weather conditions (l) extra loading (m)surface water or run-off entering the excavations or accumulating on surface near the excavation (n) inclined bedding planes “dipping” into the excavation (o) heaving or swelling of the ground at the bottom of the trench (p) subsidence alongside the excavations (q) unsafe access or egress (r) exposure of contaminated ground (s) undercutting of the excavation
4.6
SECURITY OF EXCAVATIONS
A risk assessment will be conducted in order to determine which controls will be implemented to ensure the security of excavation both during work and when left unattended. The control measures implemented will be appropriate and effective for the hazards and risks of the situation. Consideration will be given to factors such as how long the excavation will be open, and who may gain access to the excavation. The following control measures will be considered: (a) isolating the hazardous area, such as by the use of perimeter fencing, barricades, screens, barriers, handrails and/or covers, which are capable of preventing access or preventing the fall of a person (b) removal or lowering ladders on work site (c) immobilization of plant to prevent unauthorized use (d) compliance with relevant RLC/HSE requirements. (e) hazard warning lights, signs, markers or flags (f) site security measures, including fencing or use of safety observer(s) (g) night lighting.
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Signs will be erected around the site showing the name and telephone number (including after hours emergency number) of the principal contractor/contractor/RLC emergency numbers. 4.6.1
FALL PREVENTION
A safe system of work and appropriate control measures will be provided wherever persons are exposed to a risk of falling during excavation work. It is a RLC/HSE requirement to effectively fence all excavations and holes more than 1.2m deep. It will also be noted that all platforms, open sides of stairways and stairway landings will be fenced. In addition to the security measures listed above, the following measures to prevent falls will be considered: (a) use of intermediate platforms for deep excavation (b) provision of a safe means of movement between different levels of the excavation (c) provision of an adequate fall arrest system (d) backfilling as work progresses Control measures will be properly installed and maintained until the work is completed or until there is no longer any risk of persons falling into the excavation. 4.6.2
PREVENTION OF DROWNING
Where, during excavation work, and excavation is likely to collect or retain water so as to create a hazard to persons in the vicinity, the excavation will be covered or fenced off. Control measures will be provided where there is a risk of a person drowning as a result of a fall into water or other liquid, eg slurry. The following measures will be considered: (a) provision of positive means of fall protection such as fencing, handrails and safety harness (b) provision of an observer. 4.7
UNDERGROUND SERVICES
Before starting the work, the location of any underground services (eg. electricity, telecommunication cables, etc) will be identified. Wherever service plans are available they will be obtained by the principal contractor and also provided to the contractor and operator carrying out the excavation work. The
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contractor will allow for inaccuracies and the possibility of other unknown or hidden services. Further, the principal contractor will arrange for these services to be clearly marked according to the available plans and on site checks prior to commencement of work. Services will be exposed at sufficient intervals to positively identify their location and/or lie. The following are ways of checking for underground services: (a) using remote location devices (b) hand digging, using hand tools with non-conductive handles. All persons whose work may be affected by an underground service will be advised of the location of every underground service. Appropriate control measures will be implemented after consultation with relevant service providers. These measures may include the protection, or removal of services to ensure safety of workers. 4.8
EXCAVATIONS ADJACENT TO BUILDINGS OR STRUCTURES
The contractor will ensure that excavation work which is likely to reduce the security or stability of any part of any building or structure will not be commenced or continued unless adequate steps are taken before and during the progress of the work to prevent danger to any person from collapse of the building or structure or a part of a building or structure. In assessing the risk, measures such as the following will be considered before starting excavation work: (a) seeking advice from appropriately qualified engineers (b) undertaking a geotechnical analysis (c) engaging a competent person to supervise the progress of the excavation work (d) underpinning of structures (e) construction of effective retaining walls (f) minimizing ground disturbance and vibration by taking into the location of machinery, the sequence of work, the impact, severity and scale of excavation (g) backfilling as work progresses (h) evacuation of affected areas. The contractor will also ensure the stability of vehicular access which might be affected by the work.
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4.9 PROTECTION AGAINST RISING, IRRUPTIONOR INRUSH OF WATER OR MATERIAL The contractor will ensure that where there is risk from rising water or from an eruption of water or material, the means to enable every person to reach a position of safety will be provided. If a risk assessment reveals a risk of rising, irruption or inrush of water or material, appropriate control measures will be provided. These may include the following: (a) provision of exploratory or warning holes where water flows at a reduced rate to warn of danger (b) provision of sumps (c) lowering the water table (eg use of spear pumps) (d) increasing exit points eg increasing the number of exit ladders (e) provision of pumps 4.10 MATERIALS AND LOADS ABOVE AND NEAR EXCAVATIONS To reduce the risk of excavation collapse, excavated or other loose material will be effectively stored or retained away from the excavation. Excavated material will be placed outside the zone of influence. Alternatively the system will be designed to accommodate such additional load including ground water pressures, saturated soil conditions and saturated materials. Mechanical plant, vehicles, storage of materials or any heavy loads will be prevented from approaching within or encroaching on the zone of influence of the excavation unless the system has been specifically designed for such loads. Where the risk assessment has identified a risk of collapse as a result of loads or materials above or near the excavation, shoring will be in place before any person enters the excavated area. The following measures will also be considered before starting excavation work: (a) controlling access to exclude persons from hazardous areas, eg relocating means of access (b) moving and storing loads outside the zone of influence of the excavation (c) provision of wheel stoppers to limit movement of mobile equipment adjacent to the excavation (d) reducing the number of trench shields stored near excavation by pulling along trench shields and backfilling as the excavation progresses
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(e) securing all loose materials in place. When working on a slope, a risk assessment will be conducted to determine the safest side of the excavation to dump soil and excavated material. This will often be on the lower side of the slope to reduce the risk of wall collapse or material falling into the excavation. Site factors will be considered. 4.11
PROTECTION FROM FALLING OBJECTS
The risk assessment will be used to determine appropriate control measures to protect persons from accidental falls of objects including tools, plant and other construction materials. As far as practicable, loads will not be suspended or travel over a person. The following control measures will be considered: (a) fences (b) hand rails and toe boards (c) overhead protection (d) enclosed walkways (e) safety helmets and other adequate means of protection (f) provision of safe means of lowering and raising plant, materials, spoil, etc (g) use of lanyards to secure loose tools (h) loads will be lifted/suspended within the safe working limits of the machinery load used. 4.12
ELECTRICAL HAZARDS
Specific control measures will be implemented when work is done in the vicinity of power lines whether they are overhead or underground. A power line or electrical conductor will always be assumed to be energized or ‘live’, including when a communication cable or wire is encountered. 4.12.1
UNDERGROUND ELECTRICAL HAZARDS
A safe system of work will be devised to address electrical hazards associated with underground services as the following: (a) de-energizing and isolating the cables and obtaining documentary evidence of the continuing isolation of the power supply before proceeding with the work (b) a system of lock out and lock out tags (c) use of electronic surveillance prior to excavation to determine location of services. (d) hand digging using tools with non conductive handles (e) wearing rubber boots and insulating gloves
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OVERHEAD POWER LINES
When cranes, excavators, earthmoving machines or similar appliances are operated near overhead power lines the following provisions will be observed: (a) A thorough examination of the approaches and surroundings of the site will be carried out before taking an appliance to the site or setting it up. 4.13
MANUAL HANDLING
Manual Handling requires engineers and supervisors to design equipment, tasks and work environments so that manual handling risks are eliminated or reduced as far as reasonably practicable. The contractor will assess and control the risks involved in carrying out manual handling tasks. This will be done in consultation with employees who are required to carry out the work. The contractor will control risks by: (a) deg or re-deg the manual handling task to eliminate or control the risk factor. Where re-design is not practicable, the employer will: • provide mechanical aids and/or personal protective equipment. Using powered mechanical equipment to lift and move materials may control manual handling risks. Lifting equipment will include cranes, forklifts. (b) providing appropriate training to employees in safe handling techniques. This training will also include the prevention of manual handling injuries by an approach based on a hazard identification, risk assessment and control through job and task design. Employees will receive appropriate training in methods of manual handling involving team lifting procedures, correct use of the mechanical aids and PPE. (c) weights that are manually handled will be minimized. Furthermore persons will not be required to lift, lower or carry loads above 25kg, unless mechanical assistance and/or team lifting arrangements are provided to lower the risk of injury. (d) where manual handling involves repetitive bending, twisting, over-reaching, work overhead or where persons have pre existing injuries, these loads will be further decreased. Often used items such as tools, etc, will be stored at waist level. Where possible, most commonly used items will be stored between thigh and chest height. (e) the rotation of work duties will be considered in consultation with employees so that employees are not subjected to the same task for the whole shift. (g) ensuring that work areas and ageways are kept clean and clear of debris. Slippery floors and surfaces and trip hazards will be controlled. 4.14
ACCESS
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An assessment of access requirements will take into the number of persons using them and any tools and equipment that they may be required to carry to and from the work site. Control measures may include: (a) proper storage of materials and plant (b) keeping work areas and ageways clear and free of obstructions (c) removal of rubbish, including construction waste and excess excavated material (d) use of handrails (e) traffic and plant controls (f) safety fences and warning signs. 4.14.1
LIGHTING
Adequate lighting (natural or artificial) will be provided to ensure the work areas and access ways are well lit. Adequate local lighting will be provided for detailed work, for dangerous processes and where machinery is being operated. When artificial lighting is used, including lighting for night work, the contractor will ensure it does not create excessive glare or shadows. 4.14.2
RAMPS
When access ramps are provided they will not exceed 1:2.7 (20 degrees). Ramps steeper than 1:8 (7 degrees) will be cleared, grated or have surfaces which allow adequate foot grip. Where such ramps form part of an excavation, a risk assessment will be conducted to determine the maximum safe soil height above the ramp before some sort of soil (eg trench shield) is provided. Ramps will be designed and constructed to effectively withstand any anticipated load that they may be required to during use. 4.14.3
LADDERS
when ladders are used for access the contractor will provide the following: (a) the ladder will be secured at both top and bottom against displacement. Ladders will have non-slip feet and whenever practicable will be set up at an angle of 1:4 (75degrees). (b) a safe and adequately sized landing place when stepping off the ladder will be provided. (c) the stiles of the ladder will extend at least one meter above the landing place. (d) metal or wire reinforced ladders will not be used where there is a risk of with electrical conductor wires(power lines) or of electric shock. Nonconducting ladders will be used or a clearance of at least 4metres from conductors will be maintained.
METHOD STATEMENT EXCAVATION WORKS 4.14.4
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SCAFFOLDING
Scaffolding will be used to provide workers with a safe temporary work platform. It will be planned, erected, inspected and tagged by competent persons and will be regularly inspected to ensure there are no risks to safety and will comply with the requirements of RLC/HSE regulations. . 4.14.5
FIXED PLATFORMS, WALKWAYS, STAIRWAYS AND LADDERS
Fixed platforms, walkways, stairways and ladders will comply with the requirements of RLC/HSE regulations 4.15 WORKS NEAR TRAFFIC OR MOVING PLANT . Planning and preparation will also include the development of a vehicle movement procedure for each worksite. Vehicle movement procedures will identify the preferred travel paths for vehicles associated with a work site entering, leaving or crossing the through traffic stream. A vehicle movement procedure will include persons, moving equipment, plant and vehicle traffic in the work area and also identify travel paths for trucks at key points on routes remote from the work site, such as places to turn around, accesses, ramps and side roads. A vehicle movement procedure will be a documented procedure, a diagram, combined with or superimposed on a Traffic Control Plan, or may be verbal information and instructions specific to the particular construction workplace or site. The risk management process will be used to determine which is the most appropriate. A risk assessment will be conducted to determine what type of safeguards or systems of work that be implemented on the site and will include eliminating exposure of persons to moving plant. Vehicle movement procedures will be developed based on the risk assessment and will be developed each time the conditions on the site change in a way that may affect the health and safety of persons. The risk assessment will consider at least the following: (a) isolating vehicles and plant used in or around the site and work area from persons on the site or work area, eg. vehicles or persons may be guided around or past the work area. (b) securing the area where moving plant is being used eg. fencing, barriers, barricades, temporary warning or control signs or a combination. (c) planning the direction that the plant moves so that the visibility of operators is not restricted. This will also include an assessment of the visibility of plant and traffic from all areas of the work site. (d) the use of spotters/safety observers to control traffic movement (e) implementing safe working distances
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(f) the use of audible reversing alarms and/or other technologies or other safe work practices. Note: reversing alarms may cause confusion where multiple plant is using the same area and other systems of work may be required. (g) minimizing the number of moving plant working at one time. Where multiple plant is being operated around the work site a competent person will be used to direct the plant: • when operating in close proximity to each other; • when reversing; • where persons are on the ground; and • in other situations as indicated by the risk assessment. (i) where construction vehicles or plant enter or leave the work area by public roads, systems of control and notices will be placed at all entrances and exits to the work area to protect and warn all persons approaching or in the vicinity (j) where plant is being operated near persons, near underground or above ground services (any other workers, soils technicians, surveyors, visitors etc) (k) designated delivery and turning areas. The movement of delivery vehicles on construction sites frequently presents a hazard particularly when reversing, loading and unloading. Procedures will be implemented to warn all persons affected by the potential hazard. These procedures will include: • the requirement for truck drivers to report to a suitably signposted area on the site; • the requirement for a designated worker to act as an observer to ensure all persons are clear of the reversing vehicle; and • a system of communication and warning to persons near delivery point. All personnel on site will wear high visibility garments. 4.16
NOISE
Noise management provisions will be carried out by the contractor doing the work and will ensure noise levels from machinery or equipment being used do not become a risk to hearing or health. An appropriately qualified person will conduct a noise assessment to determine the level of noise that employees are exposed to. Where the noise is in excess of the noise exposure limits, engineering controls will be implemented. Where this cannot be achieved or work cannot be organized to minimize exposure, appropriate hearing protection equipment, hearing protectors, will be provided to all persons in the vicinity of the noise. The contractor will also ensure compliance with RLC Environmental Protection requirements in relation to noise.
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The contractors will ensure that all necessary prevention or protection measures are taken to ensure the health and safety of persons who may be exposed to excavated material. Where there is a risk of inhalation of harmful airborne substances such as silica dust or with harmful soil contaminants, the contractor will ensure a safe system of work. The risk assessment process will be used to determine the engineering controls, work practices and site, atmospheric monitoring required. Appropriate assessment of the exposure levels will be undertaken before selecting the control measures. The assessments will consider: (a) any persons on site, including other contractors or persons working on the site; (b) persons conducting the assessment and site remediation, including subcontract workers; (c) visitors to the site (for example, couriers); and (d) site neighbors (as appropriate). The contractor will also ensure that exposure to nonhazardous substances such as nuisance dust is at a level not greater than that established by safe exposure standards. In dry conditions, frequent watering, where practicable, or other similar methods will be used to reduce nuisance dust that will not exceed 20mg/m3. TABLE 1: TRENCHES
GASES COMMONLY FOUND IN EXCAVATIONS AND
Gases or fumes found ground Carbon dioxide, hydrogen sulfide ground
TABLE 2:
TOXIC, FLAMMABLE AND ASPHYXIATE GASES
Type of
Filled and made
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Toxic
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Flammable
Hydrogen Sulfide Carbon dioxide Employers will implement a suitable system of work so as to ensure a safe repairable atmosphere and effective ventilation and will protect persons against the effects of insufficient oxygen. These may be encountered when carrying out work such as excavations for foundations, in addition to trenches. Where the risk assessment indicates the possibility of air contamination, the work will be examined by competent persons using appropriate detecting equipment and will include air testing for: (a) oxygen deficiency (b) airborne contaminants
5.
INSPECTION AND MAINTENANCE OF PLANT AND EQUIPMENT
A risk assessment will be conducted before operating plant to identify any hazards that may arise and the control measures to be implemented. The risk assessment will consider at least the following: (a) that appropriate guards, including roll-over protective devices (ROPS) are fitted (b) that the safe working load is displayed (c) record of testing, maintenance, servicing and repair (d) the general mechanical/electrical condition of plant, especially any wear or damage that may affect safe operation (e) specific controls to prevent entanglement or workers being trapped between moving parts. All plant such as excavators, tractors, etc used for lifting will have their safe working loads displayed and maintained. If the function or condition of plant represents an immediate risk to health and safety, operation will cease and the plant will be withdrawn from use until a risk assessment and appropriate control measures are implemented.
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ROUTINE INSPECTION
Regular planned inspection and adequate maintenance will be carried out to ensure safe operation of all plant used on excavation work, whether leased, hired or owned. Both mechanical and electrical testing will be done. The following checks will also be carried out: (a) Daily checks: general condition and maintenance of the plant will be checked daily by the person doing the excavation work. (b) Regular checks: the plant will be inspected by a competent person on a regular basis, or at least every two weeks. 5.2
REPAIRS AND MAINTENANCE
The contractor will ensure the plant repairs will be carried out by a competent person and in accordance with the designer’s or manufacturer’s requirements. 5.3
REPORTING DEFECTS
Any defects to equipment will be reported immediately to the person responsible for maintaining such plant. Where a defect is likely to pose an immediate risk to health and safety the equipment or plant will not be used until the defect is rectified. 5.4
LOG BOOKS AND INSPECTION CHECK SHEETS
The contractor will keep logbooks and inspection check sheets containing a full service and repairs history of the equipment.
6.
TRAINING AND INSTRUCTION
Under RLC/HSE regulations employers will provide training, instruction, information and supervision, as may be necessary, to ensure the health and safety at work of their employees. This will be provided by a competent person. All persons involved in any excavation or associated work will: • be trained to follow systems of work and work practices that enable them to perform their work in a manner that is safe and without risks to health, and; • hold appropriate certificates of competencies where required, particularly in the operation and use of load shifting equipment. Only persons who have received training and instruction will carry out the work. The training provided and the instruction given will at least include:
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(a) induction training which complies with Construction Safety & RLC/HSE regulation (b) the work method to be used for the excavation or associated work and the manual handling procedures for the work to be carried out, including control measures based on the risk assessment to prevent injury. (c) the correct use, care and storage in accordance with the manufacturer’s recommendations where appropriate, of: • personal protective equipment; and • tools and equipment to be used. (d) the use of plant and associated equipment, including electrical safety and hazardous substances. (e) procedures to be adopted in the event of accident, injury or other emergency, including evacuation. 7.
PERSONAL PROTECTIVE EQUIPMENT(PPE)
The use of PPE to control hazards and risks is the least effective measure and is lowest on the hierarchy of control measures. Control measures will be selected from the highest level possible and be adopted where practicable. The measures at the lower levels are less effective and they require more frequent reviews of the hazards and systems of work. They will only be used when other control measures are impracticable or when, after implementing other controls, a residual risk remains. 7.1
PROVISION OF PPE
Before commencing any work, the principal contractor and or contractors will identify any conditions likely to affect the health and safety of persons. If other means of control are not practical, the provision and use of appropriate PPE that complies with the relevant RLC/HSE regulations will be arranged. Employees will be trained till they are competent in the proper selection, use and maintenance of the PPE. There will be sufficient supervision and monitoring conducted to ensure compliance. 7.1.1
SAFETY HELMETS
The use of safety helmets may prevent or lessen a head injury from falling objects or a person hitting their head against something. Where there is a likelihood of persons being injured by falling objects and overhead protection is not provided, persons will be provided with and will use an appropriate safety helmet. Appropriate safety helmets will also be provided and used where a person may strike their hand against a fixed or protruding object or where there is a risk of accidental head with electrical hazards.
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All persons on excavation sites will wear head protection that conforms to Occupational protective helmets. 7.1.2
EYE PROTECTION
Eye protection complying with RLC/HSE regulations will also be provided, where there is a risk of eye injury. Selection, use and management systems will comply with RLC/HSE regulations 7.1.3
PERSONAL HEARING PROTECTION
A noise assessment will be conducted to determine the level of noise that employees are exposed to. Where the noise is in excess of the noise exposure limits, engineering controls will be implemented. 7.1.4
HIGH VISIBILITY GARMENTS/SAFETY REFLECTIVE VESTS
Persons working near traffic, mobile plant or equipment under operator control, will be provided with and use high visibility garments. Other clothing not covered by the high visibility garment will be light colored and all garments will be selected for best contrast with the surrounding background. 7.1.5
SAFETY GLOVES
Where there is a risk of hand injury hand protection that complies with RLC/HSE regulations will be provided and used. 7.2
MAINTENANCE AND USE OF PPE
The contractor will provide such information, instruction, training and supervision as may be necessary to ensure that PPE are used and maintained as intended. All PPE used by persons during excavation work will be regularly inspected and replaced as necessary. 8.
OCCUPATIONAL HEALTH AND SAFETY
While the obligation for each person is different, all persons will ensure that the way they carry out their work will not interfere with the health and safety of the other persons who are present at the workplace. All work practices must comply with RLC/HSE regulations. CONTRACTOR’S RESPONSIBILITIES The contractor has an obligation to take reasonable care for the health and safety of the other persons in the place of work and to cooperate with their
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employer in the interests of health, safety and welfare. Employees will use appropriate protective equipment for the work being performed.
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