Construction Safety Guidelines -31 Demolition DEM MO OLITION Rev 00 December 2013 Page 1 of 14

Transcription

1 Construction Safety Guidelines -31 Demolition DEMOLITION Page 1 of 14

2 Table of Contents Purpose Scope Procedure 3. 1 General 3.2 Demolition Survey 3.33 Preferred methods of Demolition work 3.4 Demolition Method Statement 3.5 Method of Demolition 3.6 Training and Competence 3.7 Pollution Prevention 3. 8 Waste Management Reference Appendix 5. 1 Demolition Checklist Priorr to Commencement of Work. 5.2 Demolition Checklist During the Demolition Work Page 2 of 14

3 1. Purpose This procedure and guidance informationn has been produced to ensure that, prior to any demolition work commencing on the projects, a demolition survey is carried out and the subsequent demolition activities are strictly managed in accordance with a PCFC - Trakhees regulation, Approved Demolition Method Statement, Best HSE Practices, and Local Regulations. 2. Scope 2.1 This procedure and guidance will be used by members of the construction team supervision and Specialist Demolition contractors when planning, supervising and controlling demolition activities This procedure and guidance will provide assistance in the development of a Project Risk Assessment for demolition work. 3. Procedure 3. 1 General Demolition work always involve high risk and must be carried out by authorized and specialist contractor Demolition work encompasses the complete range of Constructionn hazards and an accident in demolition is much more likely to be fatal than in any other type of construction work Accidents in demolition are occur due to following cause a. Premature collapse of buildings and structures. b. Falls from working places and access routes Demolition can also produce negative impacts on the environment. The demolition assessment must include proactive measures to prevent such negative effects also Proper mode of communication should be implemented during demolition process to avoid any serious accident All the required approval / NOC must be taken from local authority (i.e. DEWA/RTA/TRAA & other local authority) Page 3 of 14

4 3.2 Demolition Survey Demolition survey must be carried out by the prospective demolition contractors prior to Demolition surveys must consider the following point: - a) Neighbors building or facility in the vicinity especially hospitals, homes or any industries were demolition can cause inconvenience. b) The condition of structural members and the contribution of floors, roofs, walls, etc to overall stability. c) Availability of old storage tanks, process vessels etc. which can cause an accident d) Overhead and underground services.. e) Safe Access and Egress for the proposed method of demolition and vehicle access for waste disposal f) Environmental impact assessment 3.33 Preferred Methods of demolition work Demolition by mechanical means is recommended to be the preferred method of working. Use of machinery such as crane or excavator mounted balling machines, heavy duty grabs, pusher arms, pneumatic drills or shears also reducee the requirement for persons working at height. However, the appointed specialist contractor must ensure that sufficient recourses are available perform the work safely. 3.4 Demolition Method Statement Page 4 of 14

5 3.4.1 Priorr to commencement of any demolition work, the contractor must prepare Demolition Method Statement, Risk assessment & Emergency produce must take approval from appointed Consultant & Local authority The planning and assessment for the method statementt should include as a minimum the following detailed information: - 1) Detailed description of the work to be carried out. 2) Approved method statement for demolition. 3) Regular Disposal of debris & other waste from floors to prevent overloading. 4) Restricted areas for unauthorized person. 5) Safe means of access and Egress 6) Details of all structures. 7) Protection against premature collapse. 8) Protection, removal and making safe all overhead and underground services. 9) Details of temporary services i.e. electricity.. 10) Proper use of personal protective equipment. 11) Traffic management plan. 12) Competent and experienced demolition team 13) Training and competence. 14) Environment protection plan 15) Emergency procedure. 3.5 Methods of Demolition Demolition by hand (Masonry and Brick Buildings). For demolition normally hand held tools are used, but the use of lifting equipment may be required to hold largerr structural members. The lifting operation activity must be properly planned. For further information refer to the EHS Lifting protocol Separate chutes should be used to dispose debris regularly If sections of floors are removed to allow the fall of debris and may be left unattended, access to these areas must be restricted from unauthorized personnel. Floor openings must be blocked off or the floor opening(s) must be protected with guard rails. Suitably fixed to prevent accidental movement. Guard rails should be fixed sufficiently away from the edges of the floor openings to ensure that they are not hit and damaged by falling debris. Safe working platforms must be installed for the operative involved in hand demolition works. Proper training must be provided to operative involve in demolition. Proper mode of communication and supervision must be there during demolition activity Page 5 of 14

6 Steel Framed Buildings Nonstructural material should be removed before the structural frame is dismantled. Each main structural member including roof trusses should be supported by crane or temporary props whilst the ends are unbolted or cut. Safe working platforms must be provided for performing demolition activity. Structural members and trusses should be carefully lowered to the ground. Where material is lowered or dropped to another level the area below must be protected to prevent unauthorized entry. Training must be provided to operative involve in demolition. Proper mode of communicationn and supervision must be there during demolition activity Demolition by Machine Prior to commencement of demolition by machine, roof structures supported on wall plates should be demolished by hand. Where the building to be demolished is attached to another structure, the two properties must be separated by a minimum of one meter using hand demolition prior to the commencement of machine demolition. Only the machine operator and a trained banks man should be allowed within a 6 meter restricted area from the section of the building being demolished The cabs of all machines should be strong enough to protect the operator from falling debris. Windscreens or roof lights in cabs should be shatterproof and protected by steel bar grilles or strong mesh. Machines must have valid test certificate from approved Third party Agency and the operator must have competency certificate Training must be provided to operative involve in demolition. Proper mode of communication and supervision must be there during demolition activity Page 6 of 14

7 Demolition by Balling Balling is normally carried out using a lattice jib crane mounted on a drag-line crawler crane chassis. The demolition ball, suspendedd from the lifting rope and swung by the drag rope should be fitted with a steel anti-spin device. Balling is a skilled operation and should be carried out by fully trained operatives under the control of experienced supervisors. Machines must be properly maintained and stand on firm level ground. Balling creates a great deal of stresses and wears on the crane and the minimum effective weight of ball should be selected. Manufactures of machines should be consulted to establish any restrictions on the type and length of jib, or the weight of the ball. The height of the jib should always be at least 3 meters above the part of the building being demolished, but the length of the jib should be decreased as the height of the building is reduced. The length of the jib is determined by the need to avoid the underside of it striking any part of the structure and for the angle of the jib not to exceed 60 degrees to the horizontal, which could cause it to spring back over the cab. Floors should be demolished by dropping the ball on to the highest remaining floor and allowing the debris to falll within the buildings. Hauling in the lifting or drag ropes whilst the ball is trapped could result in overturning of the crane or failure of the jib. If demolition is to be carried out on a building structure higher than 30 meters then only drop balling and pendulum balling should be carried out. Slew balling must not be used on heights above 30 meters. Page 7 of 14

8 Impact Hammers (Hydraulic) Impact hammers are normally mounted on track or wheel mounted excavators, a heavy duty pick, which can be vibrated by hydraulic or pneumatic power is fitted to remove material from the top of walls or columns. When using hydraulic impact hammers the course of material to be removed must not be greater than required depth as mention in regulation Steel reinforcement should be cut separately as necessary Hydraulic Pusher Arms Hydraulic pusherss arms are also normally mounted on track or wheel mounted excavators and are used for applying horizontal force to a brick or masonry wall. The machine should stand on a firm, level base and apply force by a controlled movement of the pusher arm. Page 8 of 14

9 3.5.7 Deliberate Controlled Collapse Deliberate collapse of all or part of a building requires extremely high standardss of planning, supervision and execution. Careful consideration of its effect on adjacent buildings or structures is essential. Clear areas and exclusion zones must be established. The usual method for deliberate collapse is achieved by removing key structural elements e.g. by explosives or pre-weakening them and wire rope pulling at high level to overturn the structure. Wire ropes should be attached to the structure before pre-weakening commences. Mobile working platforms or other suitable equipment may be required to gain safe access. Ropes should be in good condition, not less than 38mmm diameter and attached to winches of sufficient rope capacity and traction. The pre-weakening must be carefully planned and take into account the ability of the remaining elements to resist wind or impact loads until the intended deliberatee collapse. Indiscriminate cutting of steel members until the structure collapsess ( cut and run ) is highly dangerous and must not be carried out. In selecting appropriate methods, the possible sequencee of failure should be studied in detail. Demolition by deliberate controlled collapse is not normally suitable for pre-stressed concrete structures, except where the only pre-stressed concretee is in the form of simple pre-tensioned floor slabs. 3.6 Training and Competencee Operative involved in the demolition activities must be suitably trained, competent to carry out demolition work and acquire sufficient skill and safety awareness. The operative must be fully aware of the following:- Instruction in the requirements of the demolition method statement. Correct use of PPE. Working at heights. Lifting techniques. Hazards involved in working with lead and asbestos. Manual handling techniques. Fire prevention. Working in confined spaces. Emergency procedure Page 9 of 14

10 3.7 Pollution Prevention Water Prior to the commencement of any demolition work, precautions must be taken to secure the complete protection of rivers, streams and other water courses against silting, erosion or pollution. All fuel and chemical storage must be installed as per local laws on impervious bases and surrounded with a bund wall and located well away from watercourses or drains. Pipes may also contain significant amounts of oil or chemicals and should be capped or valves closed to prevent spillage. Effluent must not be discharged into a foul sewer from temporary toilets unless permission has been obtained from the appropriate local authority. Any spillage into watercourse or sewers must be notified immediately to the relevant local authority Air Air pollution will travel a considerable distance where winds prevail and will pose a health risk and nuisance to the immediate site neighbors who may inadvertently inhale such pollution. During demolition dust must be controlled at source to prevent spread of contamination around the site and neighboring areas. If possible, the use of plant in proximity of domestic areas should be strictly controlled to reduce exhaust emissions. To provide further protection to the local neighborhood, restrictions on working hours may also be applied and the planning of effective vehicle routes will assist in preventing unnecessary vehicle movement Noise Good relations with people living and working in the vicinity of the demolition operations will assist in preventing neighborhood disputes and complaints. All possible techniques should be investigated and used to minimize as far as possible the levels of noise transmitted into the environment. Such levels may include: - 1) Restriction on working hours. 2) Control of noise at source. 3) Substitution for quieter machinery. 4) Siting of plant and equipment. 5) Regular and effective maintenance. Noise limit shall abide by the Local laws and regulations. Page 10 of 14

11 3.8 Waste Management Existing Materials Prior to any demolition operations commencing a survey must be carried out to detect for contamination on site and if it is classed as special waste. As a result of the survey a decision must be made weather material is to be disposed of or used on site. Retentionn 1. If the material is to be retained on site then the area it is to be used in must be impervious to prevent leaching of the contaminant into the watercourse. 2. The material must be kept separately and the area must be restricted from unauthorized person. 3. The material must be segregated for recycling. Disposal An approved waste disposal contractor must be appointed for disposal of contaminated waste. The contractor should provide all the relevant information for each load being disposed and the information should include the following details: - 1) Description of the waste being transferred 2) Quantity of waste being transferred. 3) Name and address of the producer. 4) Name and address of the waste carrier complete with approved registration 5) The place of transfer. Date and time of transfer. Page 11 of 14

12 6) Local laws shall be complied with and approved certificates shall be kept for environmental audits. 4. References 1. BS 6187 Code of Practice for Demolition. 2. Code of Construction practice Dubai Municipality 3. PCFC- Trakhees Constructionn Safety Regulation 5. Appendix 5.1 Demolition Check list - Prior to Commencement of work. 5.2 Demolition Check list - During the demolition work Page 12 of 14

13 Demolition Checklist - Prior to Commencement of work Check Point Yes No Actions to be taken Are drawing available of the original structure and any other alternatives, modifications etc.? Has the building / structure to be demolished been thoroughly examined by a competent and qualified person? Has the proposed demolition contractor carried out a survey? Has the demolition contractor produced a detailed method statement? Have appointed consultant approved the method statement? Has a survey been carried out to identify the presence of any hazardous substances i.e. Asbestos, Lead, etc? Has a survey been carried out to identify any flammable gases and materials? Have systems of work been established for protection against health hazards? Have overhead and underground services been located, identified, protected and made safe? Have arrangements been made for the provision and installation of scaffolds, nets, fans, hoardings, exclusion zones etc for the protection of other persons on site and members of the public? Has notification of the demolition been sent to the concerned local authorities? 13 Have arrangements been made for the collection and disposal of hazardous substances? 14 Have suitable vehiclee wheel washers been installed at all exits from the site? Page 13 of 14

14 Demolition Check list - During the demolition work Check Point Yes No Actions to be taken 1 Is the work being supervised by a specifically appointed, competent and experienced demolition supervisor? 2 Are the demolition activities being carried out in accordance with the agreed demolition method statement? 3 Are the systems of work involving the removal of asbestos, lead, flammable materials etc as per the agreed methods? 4 Are systems of work effectivee to prevent the buildup of debris on floors, temporary structures or behind walls? Are arrangements for restricted areas and safe distances being strictly adhered to? Are all workplaces provided with safe working platforms and safe means of access? Are all temporary works i.e. scaffolds, fans, hoardings, shoring etc. suitably maintained and remain effective? Are all scaffolds inspected on a regular basis and action taken to correct any discrepancies? Are arrangements for protecting members of the public adequate? Are all members of the demolition crew issued with and wear and use suitable PPE? Are systems of work in place to ensure that isolated parts of the structure/building are not left free standing? 12 Are all positive steps being taken to prevent negative impacts on the environment? 13 Are all security gates, fences maintained in good condition and other security matters in place to prevent unauthorized entry onto the site? Page 14 of 14