Managing safety and health at metal scaffolding work
A safety management system and a safe system of work should be developed, implemented and maintained for the safety and health at work of workers. Further reference should be made to the Factories and Industrial Undertakings (Safety Management) Regulation. Among other things, the following actions should also be taken into account:
4.1 Design and initial planning
A construction project should be designed with safety in mind. This approach makes it possible to eliminate or minimize the work hazards by proper planning and design of the methods of construction, sequences of activities, coordination, etc.
4.1.1 During the design of a metal scaffold, attention should be paid in the following areas:
(a) The safe scaffold and its erection/alteration/dismantling for all different stages of construction should be designed and planned well beforehand.
(b) The safe method of scaffolding devised should be kept under continual review.
(c) The strength and stability of the scaffold throughout all stages of scaffolding should be ensured.
(d) The strength of scaffolding members such as tubes and couplers should be ensured. Reference should be made to the procedures laid down in relevant standards of the International Organization for Standardization or equivalent procedures for their sampling and mechanical testing.
(e) Realistic assessment of loadings on the scaffold at all work stages should be made. In considering the wind load on the scaffold, reference should be made to the Code of Practice on Wind Effects in Hong Kong, 2004 (Buildings Department).
(f) Safe access to and egress from the working places should be provided.
(g) Effective bonding system to earth should be provided to the scaffold.
(h) Additional features such as attachment points for ladders, working platforms, guard-rails and toe-boards should be provided for the protection of workers using the scaffold. Safety nets and safety belts should also be provided for the protection of scaffolders.
(i) Scaffolding components/materials/equipment should be handled, lifted, stored, stacked and transported safely.
(j) The time when the scaffold would be erected and dismantled should be decided in the design and planning stage. The scaffold should be dismantled as soon as it is no longer required to be used.
4.1.2 Specification for scaffolding contract document:
(a) Specification for scaffolding contract document should incorporate particular requirements and essential information for the scaffolding work to be planned and implemented safely. (For example, the provision of design drawings and method statement; phasing of work – particularly with other contractors; periodic maintenance and repair of scaffold.)
(b) Special requirements relating to compliance with safety legislation should be highlighted and, where appropriate, these items should be included in the Bills of Quantities.
(c) Depending on the size of the project and/or the complexity of the work involved, tenderers for the scaffolding work should be required to submit an outline scaffolding plan at tendering stage, giving sufficient information to demonstrate their intended safe system of work.
4.1.3 Coordination and communications:
(a) There should be close liaison between all relevant parties even at the design and planning stage.
(b) Effective lines and systems of communication should be devised for each stage of the scaffolding work and a person should be assigned to maintain effective communication.
4.1.4 Initial planning:
(a) Site considerations and risk assessment
Potentially hazardous site features and other aspects likely to impair safe scaffolding should be identified. The risk arising from each individual hazardous event should be evaluated according to its probability and consequence. The following special conditions of the site should be taken into account:
(i) The existence of overhead electric power lines.
(ii) The existence of overhead signboards or projections,
particularly those in the urban areas.
(iii) The existence of buried services, including underground electric cables, gas or other fuel pipelines.
(iv) The existence of storage tanks.
(v) Restricted access to, and onto the site.
(vi) Restricted space for erection, manoeuvring, storage and, if required, for on-site pre-assembly or fabrication.
(vii) Low ground bearing pressures that may be due to, for example, made ground or existing underground services or structures.
(viii) The proximity and condition of other buildings and premises that may by itself or so-induced special wind effect (for example, funnelling effect) affect the planned method of scaffolding.
(ix) The shape and the structure of the building. (x) The juxtaposition of the public and the site. (xi) The activities of other contractors.
(xii) The existence of noxious gases, chemicals, fluids or dust
emitted from processes on or around the site.
(xiii) The proximity of the site to seashore where the strength of the scaffolding may be affected by seawater.
(b) Preliminary method statement
The preparation of a preliminary method statement is an important part of planning for a safe system of work in scaffolding. Where appropriate, a preliminary method statement should include:
(i) the arrangements for coordination and the responsibilities and authority of supervisory personnel during scaffolding work;
(ii) the scaffolding sequences including erection and dismantling;
(iii) the methods of ensuring stability with due consideration of future construction activities (for example, trench work, external building services /facilities installation);
(iv) the detailed scaffolding work method which should ensure that the work could be carried out safely;
(v) the construction tolerance;
(vi) the assessed maximum allowable loading (includes vertical and lateral loads) on the scaffold/working platform;
(vii) the provisions to prevent falls from height, including safe means
of access and egress and safe places of work;
(viii) the protection from falls of materials, tools and debris, and the
provision of catch-fans and protective screens at the scaffold;
(ix) the provision of suitable plant, tools and equipment;
(x) the arrangements for delivery, stacking, storing and movement on site for scaffolding components, materials and equipment;
(xi) the details of site features, layout and access; and
(xii) the contingency arrangements.
4.2 Selection of subcontractor for metal scaffolding work
4.2.1 If a subcontractor is to be engaged in metal scaffolding work, whether he would make adequate provisions for safety and health should be an important selection consideration. Selection criteria should also include the ability of the subcontractor in providing a good scaffolding plan.
4.2.2 During the process of selection, the subcontractor should be required to submit an outline scaffolding plan, giving preliminary information to demonstrate the intended safe system of work. Depending on the complexity of the project, the outline scaffolding plan should briefly describe items such as safety organization, communication, monitoring, equipment, facilities, emergency procedures, accident reporting, and accident investigation procedures.
4.2.3 After the subcontractor has been appointed, he is required to finalize a detailed scaffolding plan on the basis of the outline scaffolding plan if any, for agreement in writing. The detailed scaffolding plan should spell out the ways and means to carry out work safely and effectively in order to fulfil the objective of protecting workmen at work. The detailed scaffolding plan should also be incorporated into the safety plan of the main project.
4.3 Site management and procedures
4.3.1 Managing for safe erection/alteration/dismantling
Safe working methods and practices on site should be ensured as follows:
(a) Preparation and use of a detailed method statement
The extent of detail in a detailed method statement will depend upon the size and/or complexity of the work, with a simple job requiring a simple method statement and repetitive tasks being covered by standard sheets. Preliminary method statement produced at the planning stage should be developed into a detailed method statement that should be incorporated into the detailed scaffolding plan. The whole method statement should be reviewed and updated as necessary so that it remains current. It should be distributed to all those concerned with the supervision of scaffolding work.
(b) Thorough and active contract coordination both on and off site
Coordination and liaison between parties should be maintained throughout the job. Any changes in previously agreed procedures must be verified by the person responsible for coordination as being safe before they are implemented. Matters that will contribute to safe scaffolding work on site, including the availability of information, plant and manpower, and the quality and supply of materials should also be coordinated.
(c) Implementation and maintenance of effective communications
To ensure that precautions for safe scaffolding outlined in the method statement are followed, lines of communication should be clearly designated, with the responsibility for implementing the method statement well defined.
(d) Contingency plan for adverse weather conditions
Weather conditions that could have an adverse effect on the scaffolding work such as rain, high wind, lightning or typhoon, and those causing poor visibility, such as fog, mist or glare should be constantly monitored.
If a decision is made to stop work, then measures should be taken to maintain the stability of the scaffold and the plant, equipment and works erected on the scaffold.Also, all personnel should be safely and efficiently evacuated from the scaffold. After the adverse weather, the scaffold should be inspected and certified in safe working order by a competent person and all the plant, equipment and works erected on the scaffold should be checked and confirmed to be in order before work is to be restarted.
(e) Provision of suitable staff
No scaffold shall be erected on the site or substantially added to, altered or dismantled except under the immediate supervision of a competent person and by trained workmen possessing adequate experience of such work (Regulation 38E of the CSSR). Training should be a continuing process with on-the-job instruction and formal training sessions provided as appropriate (refer to Section 4.6).
(f) Provision of protective equipment
Protective equipment that is necessary and appropriate for the work should be provided. Examples of protective equipment are: safety helmets, safety nets and safety belts with suitable anchorage.
4.3.2 Preparing the site and the work
(a) Plans and drawings should be checked for matters relating to scaffolding safety before work is to be started.
(b) The need to exclude other personnel from scaffolding areas when scaffolding work is in progress should be considered.
(c) Site inspection should be conducted to check the physical
conditions, the hazards involved and other special features. (d) The ground condition should be made firm, level and suitable.
(e) The maximum safe loading (includes vertical and lateral loads)
imposed on the scaffold should be assessed, and strictly adhered to.
(f) The scaffolding members should be checked for their fitness before despatching to the site. Defective materials should be prohibited to be used and should be removed from site as soon as possible. During their stay on site pending for removal, they should be properly labelled to show that they are defective and should not be used.
(g) A suitable place should be provided at the site for storage of scaffolding members and the associated materials, tools or equipment. Also, they should be properly stacked and tied to prevent accidental displacement and collapse. The storage area should be clearly shown on the site plans.
(h) Documents such as scaffolding plan, method statement, design drawings and specifications of the scaffold, etc. should be made available to all parties concerned in good times.
4.4 Working places and access
4.4.1 Working platform of scaffold
(a) A method statement for construction of a working platform should be devised. Please refer to Section 4.3.1 (a) on method statement.
(b) Guard-rails and toe-boards shall be installed at edges where persons are liable to fall from height. The guard-rails shall have adequate strength and be securely fixed. The height of a top guard-rail shall be between 900mm and 1 150mm above the platform. The height of an intermediate guard-rail shall be between 450mm and 600mm above the platform. The height of a toe-board shall be not less than 200mm (Third Schedule to the CSSR).
4.4.2 Safety net
Provision of a workplace without risk of falling should always be the first consideration. However, if this is not practicable, safety nets and safety belts shall be used (Regulation 38H of the CSSR). Reference should be made to national/international standards or provisions for the standards of safety nets and safety belts.
4.4.3 Safety belt
In all the circumstances of the case, if it is impracticable to provide safety net, wearing of safety belt with effective anchorage system is required as the last resort for fall prevention (Regulation 38H of the CSSR). Further reference should be made to the Guidance Notes on Classification and Use of Safety Belts and their Anchorage Systems prepared by the Labour Department. It is strongly recommended that, when a choice of safety belt is possible, a safety harness incorporating buttock straps, as distinct from a general purpose safety belt, should be used.
4.4.4 Provision of catch-fan and protective screen
(a) At least a sloping catch-fan at not more than 15m vertical
intervals to give a minimum horizontal projection coverage of
1 500mm should be provided. The sloping catch-fan should consist of timber boarding and a layer of galvanized metal sheeting, both of adequate thickness to capture and retain falling objects.
(b) A suitable receptacle should be provided within each catch-fan to trap falling objects. The weight of the receptacle should not affect the stability of the catch-fan.
(c) The sloping catch-fan and receptacle should remain in place until all works are completed.
(d) On the face of the scaffold, suitable protective screen of fire retardant material should be provided to confine falling objects. If tarpaulin is being used as protective screen, its fire retardant characteristic should meet the requirements of BS 5867-2:2008 (Type B performance requirements) or other equivalent national/ international standards or provisions.
4.5 Monitoring safety performance
4.5.1 Requirements on safety and health, particularly those relating to compliance with safety legislation, are advisable to be incorporated into the conditions of contract for engagement of subcontractor for metal scaffolding work or other subcontractors using the scaffold.
4.5.2 Regular records on the safety conditions of the scaffolding should be kept.
Such records should consist of detailed information on work hazards, precautions taken, accident analysis and recommendations. These records should be constantly reviewed for hazard identification and improvement.
4.5.3 Workmen’s feedback on the safety conditions of the site should be encouraged and as far as possible documented.
4.5.4 A monitoring system should be developed, implemented and maintained on site for checking the safety performance of the subcontractor for metal scaffolding work or other subcontractors using the scaffold against the requirements mentioned in Section 4.5.1.
4.6 Training of metal scaffolders
4.6.1 The objective of training is to increase the efficiency of workers and to improve safety performance in erecting, altering, maintaining and dismantling scaffolds. The importance of ensuring that workers who erect, alter, maintain and dismantle scaffolds are fully competent is obvious, but the degree of skills which are required differ according to the duty to be performed. There is a great span of proficiency and experience required. Properly controlled training is therefore vital for safety and it would eventually attract a better type of man to make a career in the industry. Before training of the scaffolders is to be considered, they should be physically fit for the scaffolding work first.
4.6.2 Training of scaffolders needs to relate to basic site safety, familiarity with everyday hazards and the requirements for a safe place of work. In general, training for scaffolders should start at ground level, where basic skills can be acquired, and when scaffolders are proficient, using those skills at increasing height would be appropriate. Training should continue after basic skills have been acquired to ensure that scaffolders are familiar with improvements in techniques, the use of newly developed equipment/materials, and to ensure that safe methods of work continue to be used.
4.6.3 When a new scaffolder is employed, the management should ascertain the previous safety training of him, and should not assume that any scaffolder has a particular skill or training without seeing some proof or demonstration. Induction training will be needed to explain such matters as the company’s safety policy/organization, company safety rules, accident reporting requirements, etc. Besides, training/instruction would be necessary when the new scaffolder first starts on a project, to cover the particular requirements of the site such as emergency procedures, any special hazards and the safety aspects of the scaffold.
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