OISD-GDN-192 Safety Practices During Construction (PDF)

OISD/DOC/08/2023/09 OIL INDUSTRY SAFETY DIRECTORATE d ite निर्माण के दौर...

OISD/DOC/08/2023/09 OIL INDUSTRY SAFETY DIRECTORATE d ite निर्माण के दौरमि सरु क्षम प्रथमएं ओ आई एस डी–जी डी एि- 192 m Li SAFETY PRACTICES DURING CONSTRUCTION y er OISD-GDN-192 in ef R h ar ig al um Inception August 2000 N Revised Edition April 2016 FOR RESTRICTED CIRULATION ONLY OIL INDUSTRY SAFETY DIRECTORATE Government of India Ministry of Petroleum & Natural Gas 8th Floor, OIDB Bhavan, Plot No. 2, Sector – 73, Noida – 201301 (U.P.) Website: https://www.oisd.gov.in Tele: 0120-2593833  OISD/DOC/08/2023/09 Page No. I PREAMBLE Indian petroleum industry is the energy lifeline of the nation and its continuous performance is essential for sovereignty and prosperity of the country. As the industry essentially deals with inherently inflammable substances throughout its value chain – upstream, midstream and downstream – Safety is of paramount importance to this industry as only safe performance at all times can ensure optimum ROI of these national assets and resources including sustainability. While statutory organizations were in place all along to oversee safety aspects of Indian petroleum industry, Oil Industry Safety Directorate (OISD) was set up in 1986 by Ministry of Petroleum and d Natural Gas, Government of India as a knowledge centre for formulation of constantly updated world- scale standards for design, layout and operation of various equipment, facility and activities involved ite in this industry. Moreover, OISD was also given responsibility of monitoring implementation status of these standards through safety audits. m In more than three decades of its existence, OISD has developed a rigorous, multi-layer, iterative Li and participative process of development of standards – starting with research by in-house experts and iterating through seeking & validating inputs from all stake-holders – operators, designers, national level knowledge authorities and public at large – with a feedback loop of constant updation y based on ground level experience obtained through audits, incident analysis and environment er scanning. in The participative process followed in standard formulation has resulted in excellent level of compliance by the industry culminating in a safer environment in the industry. OISD – except in the ef Upstream Petroleum Sector – is still a regulatory (and not a statutory) body but that has not affected implementation of the OISD standards. It also goes to prove the old adage that self-regulation is the R best regulation. The quality and relevance of OISD standards had been further endorsed by their adoption in various statutory rules of the land. h ar Petroleum industry in India is significantly globalized at present in terms of technology content requiring its operation to keep pace with the relevant world scale standards & practices. This ig matches the OISD philosophy of continuous improvement keeping pace with the global developments in its target environment. To this end, OISD keeps track of changes through al participation as member in large number of International and national level Knowledge Organizations – both in the field of standard development and implementation & monitoring in addition to updation um of internal knowledge base through continuous research and application surveillance, thereby ensuring that this OISD Standard, along with all other extant ones, remains relevant, updated and effective on a real time basis in the applicable areas. N Together we strive to achieve NIL incidents in the entire Hydrocarbon Value Chain. This, besides other issues, calls for total engagement from all levels of the stake holder organizations, which we, at OISD, fervently look forward to. Jai Hind!!! Executive Director Oil Industry Safety Directorate  OISD/DOC/08/2023/09 Page No. II FOREWORD The Oil Industry in India is over 100 years old. As such, various practices have been in vogue because of collaboration/ association with different foreign companies and governments. Standardization in design philosophies, operating and maintenance practices remained a grey area. This coupled with feedback from some serious accidents that occurred in the past in India and abroad, emphasized the need for the industry to review the existing state-of-the-art in designing, operating and maintaining of Oil and Gas installations. With this in view, the Ministry of Petroleum and Natural Gas in 1986 constituted a Safety Council assisted by the Oil Industry Safety Directorate (OISD) staffed from within the industry in formulating d and implementing a series of self-regulatory measures aimed at removing obsolescence, standardizing ite and upgrading the existing standards to ensure safe operations. Accordingly, OISD constituted a number of functional committees of experts nominated from the industry to draw up standards and guidelines on various subjects. m The present guideline on “Safety Practices During Construction” has been prepared by the functional Li committee based on, existing standards, guidelines & recommended practices of OISD, the recommendations arising out of recent major accidents and their analysis, the accumulated knowledge y and experience of industry members in India and updation of National and International codes and er practices. in The figures and photographs used in the document, if any, are representative in nature. ef We, at OISD, are confident that the provisions of this standard, when implemented in totality, would go a long way in ensuring safe operation of the target group of locations. R Needless to mention, this standard, as always would be reviewed based on field level experience, h incident analysis and environment scanning. Suggestions from all stake holders may be forwarded to OISD. ar ig al um N  OISD/DOC/08/2023/09 Page No. III NOTE Oil Industry Safety Directorate (OISD) publications are prepared for use in the Oil and Gas industry under Ministry of Petroleum & Natural Gas. These are the property of Ministry of Petroleum & Natural Gas and shall not be reproduced or copied and loaned or exhibited to others without written consent from OISD. Though every effort has been made to assure the accuracy and reliability of the data contained in these documents, OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from their use. These documents are intended only to supplement and not to replace the prevailing statutory d requirements of PESO, DGMS, Factory Inspectorate or any other Government body which must be followed as applicable. ite Wherever Acts/ Rules/ Regulation and National/ International Standards are mentioned in the m standard, the same relates to in-vogue version of such documents. Li y er in ef R h ar ig al um N  OISD/DOC/08/2023/09 Page No. IV SECOND FUNCTIONAL COMMITTEE ON CONTRACTOR SAFETY LIST OF MEMBERS Name Organization Status S/Shri A K Gupta DGM (HSE), IOCL Leader Dharmvir Addl. Director, OISD Member Coordinator d ite Ashok Dashputre Vice President, RIL Member P K Agarwal CM (HSE), IOCL Member m D Jana AGM-Construction, EIL Member Li Udoay Payyadi Sr. Manager-Maintenance, HPCL Member Vijay Mohan Addl. Director, CHT y Member er B K Rabha Dy. CE(Instrumentation), OIL Member in Sankar Raman V CM-E&C, BPCL - Kochi Refineries Ltd. Member ef Yogesh J Nakhare Manager-F&S, HPCL. Member R Pushp Khetarpal Sr. Vice President (O&M), Petronet LNG Member h Upinder Kumar Petronet LNG Member ar A K Arora Addl. Director, OISD Member ig al In addition to the above, several other experts from Industry contributed in the preparation, review and finalisation of this Guideline. um N  OISD/DOC/08/2023/09 Page No. V FIRST FUNCTIONAL COMMITTEE ON SAFETY PRACTICES DURING CONSTRUCTION NAME ORGANISATION LEADER Shri A.K. Tandon EIL, New Delhi. MEMBERS d 1. Shri U.M. Rao GAIL, Noida. ite 2. Shri K.N. Ravindran CRL, Cochin 3. Shri P.K. Anand ONGC, Mumbai. m 4. Shri H.N. Das ONGCL, Nazaria. Li 5. Shri Jagnandan Tyagi IOC(PL) Nodia. 6. Shri M.C Lohar y IBP Co. Ltd., Calcutta. er 7. Shri J.C. Agrawal IOC, Mktg, New Delhi. in 8. Shri S.M. Ghotavadekar HPCL, Mumbai. ef 9. Shri Sanjoy Ghose BPCL, Mumbai. R 10. Shri H. C Jha “Hari” IOC-Panipat Refinery. h 11. Shri Suhas Kate HPCL, Visakh. ar Member-Coordinator ig Shri A.K. Ranjan OISD, New Delhi al um N  OISD/DOC/08/2023/09 Page No. VI CONTENTS SECTION Page No. 1.0 Introduction 1 2.0 Scope 1 3.0 Definitions 1 4.0 General Duties 2 d 4.1 General Duties Of Execution Agencies 2 ite 4.2 General Duties Of Owners 4 m 5.0 Safety Practices At Work Places 4 Li 5.1 General Provisions 4 5.2 Means Of Access And Egress 5 y 5.3 Housekeeping er 5 5.4 Precautions against The Fall Of Materials and Persons in and Collapse Of Structures 6 ef 5.5 Prevention Of Unauthorised Entry 6 R 5.6 Fire Prevention And Fire Fighting 6 h 5.7 Lighting 7 ar 5.8 Plant, Machinery, Equipment and Hand Tools 7 ig 6.0 Construction Activities 9 al 6.1 Excavation 10 um 6.2 Scaffolding, Platforms & Ladders 12 N 6.3 Structural Work, Laying of Reinforcement & Concreting 22 6.4 Road Work 26 6.5 Cutting/Welding 27 6.6 Working in Confined Spaces 29 6.7 Proof / Pressure Testing 31 6.8 Working at Heights 31 6.9 Handling and Lifting Equipment 34  OISD/DOC/08/2023/09 Page No. VII 6.10 Vehicle Movement 39 6.11 Electrical 40 6.12 Offshore 43 6.13 Demolition 48 6.14 Radiography 49 6.15 Sand/Shot Blasting / Spray Painting 50 6.16 Work above Water 51 d 7.0 Additional Safety Precaution for Units with Hydrocarbons 52 ite 8.0 Environment Protection 53 m 9.0 Occupational Health 55 Li 10.0 Documentation 56 11.0 Safety Awareness & Training 56 y 12.0 References er 57 in Annexure I 58 ef R h ar ig al um N  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 1 SAFETY PRACTICES DURING CONSTRUCTION SAFETY PRACTICES DURING CONSTRUCTION 1.0 INTRODUCTION Safety in Construction Management deserves utmost attention especially in the hydrocarbon industry, such as Exploration, Refineries, Pipelines and Marketing installations, Gas Processing units etc. Construction is widely recognised as one of the accident prone activities. Most of the accidents are caused by inadequate planning, failure during the construction process and/or because of design deficiencies. Besides property loss, accidents also result in injuries and fatalities to the personnel, damage to environment which needs to be prevented. d The reasons for accidents during construction activities are related to unique ite nature of the industry, human behaviour, difficult work-site conditions, extended odd duty hours, lack of training & awareness and inadequate safety m management. Unsafe working methods, lack of proper JSA (Job Safety Analysis) and use of improper / inadequate PPEs, equipment failure and improper housekeeping also tend to increase the accident rate in construction. Li Ensuring good quality of materials, equipment and competent supervision along with compliance of standard engineering practices shall go a long way to in built safety into the system. y er The objective of this document is to provide practical guidance on technical and educational framework for health, safety and environment in construction with a in view to: (a) prevent accidents and harmful effects on the health of workers arising ef from employment in construction; (b) ensure appropriate safety during implementation of construction; R (c) provide safety practice guidelines for appropriate measures of planning, control and enforcement. (d) protect environment. h ar 2.0 SCOPE ig This document specifies broad guidelines on HEALTH, SAFETY AND ENVIRONMENT practices to be adhered to during construction activities al including green field projects in oil industry. However, before commencing any job, specific hazards and its effects should be assessed and necessary um corrective/preventive actions should be taken by all concerned. The document is intended only to supplement and not to replace or supersede the prevailing statutory requirements, which shall also be followed as applicable. For Personal Protective Equipment, OISD-STD-155 (Part I&II) shall be referred to. The scope N of this document does not include the design aspects and quality checks during construction. 3.0 DEFINITIONS Definitions of various terminology are given below: Adequate, appropriate or suitable are used to describe qualitatively or quantitatively the means or method used to protect the men, machinery, material, property and enviroment. By hand: The work is done without the help of a mechanised tool. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 2 SAFETY PRACTICES DURING CONSTRUCTION Competent Authority: A stautory agency having the power to issue regulations, orders or other instructions having the force of law. Competent person: A person possessing adequate qualifications, such as suitable training and sufficient knowledge, experience and skill for the safe performance of the specific work. The competent authorities may define appropriate criteria for the designation of such persons and may determine the duties to be assigned to them. Construction site: A worksite involving new construction, modification or maintenance of existing facility, shutdown related activity, demolition, housekeeping etc. d ite Environment: Environment includes water, air and land and the interrelationship which exists among and between water, air and land and human beings, other m living creatures, plants, microorganisms and property. Li Execution agency: Any entity / person, having contractual obligation with the owner and who y employs one or more workers on a construction site. er Hazard: A condition or a set of conditions which has potential of causing injury to person, damage to property or environment. in Health: Soundness of body covering Physical, Emotional, Psychological ef and Intellectual conditions of a worker which assists the attainment of the objectives. R Means of access or egress: Passageways, corridors, stairs, platforms, ladders and any other means for entering or leaving the workplace or for escaping in case of danger. h ar Owner: Any entity / person for whom construction job is carried out. It shall also include owner's designated representative/ consultant/ ig nominee/ agent, authorised from time to time to act for and on its behalf for supervising/ coordinating the activities of the execution agency. al Scaffold: Any fixed, suspended or mobile temporary structure supporting um workers and material or to gain access to any such structure and which is not a lifting appliance. Safety : Prevention & protection from exposure to Hazard. N Worker: Any person engaged in construction activity. Workplace: Owner’s designated premises where workers need to be present by virtue of their involvement in the construction activity. 4.0 GENERAL DUTIES 4.1 GENERAL DUTIES OF EXECUTION AGENCIES 4.1.1 Execution agency should: i) provide means and organisation to comply with the Health, safety and environment protection measures required at the workplace. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 3 SAFETY PRACTICES DURING CONSTRUCTION ii) provide and maintain workplaces, plant, equipment, tools and machinery and organise construction work so that, there is no risk of accident or injury to health of workers. In particular, construction work should be planned, prepared and undertaken so that: (a) dangers liable to arise at the workplace, are prevented; (b) excessively or unnecessarily strenuous work positions and movements are avoided; organisation of work takes into account the safety and health of workers and also environment protection; d materials and products used are suitable from Health safety and environment protection point of view; ite (c) working methods are adopted to safeguard workers against the harmful effects of chemical, physical and biological m agents. iii) establish committees with representatives of workers and Li management or make other arrangement for the participation of workers in ensuring safe working conditions. iv) y arrange for periodic safety inspections by competent persons of er all buildings, plant, equipment, tools, machinery, workplaces and review of systems of work, regulations, standards or codes of practice. The competent person should examine and ascertain the in safety of construction machinery and equipment. ef v) provide such supervision to ensure that workers perform their work with due regard to safety and health of theirs as well as that R of others. vi) employ only those workers who are qualified, trained and suited h by their age, physique, state of health and skill. ar vii) satisfy themselves that all workers are informed and instructed in the hazards connected with their work and environment and trained in the precautions necessary to avoid accidents and injury ig to health. al viii) ensure that buildings, plant, equipment, tools, machinery or workplaces in which a dangerous defect has been found should um not be used until the defect has been rectified. ix) organise for and remain always prepared to take immediate steps to stop the operation and evacuate workers as appropriate, where N there is an imminent danger to the safety of workers. x) establish a checking system by which it can be ascertained that all the members of a shift, including operators of mobile equipment, have returned to the camp or base at the close of work on dispersed sites and where small groups of workers operate in isolation. provide appropriate first aid, training and welfare facilities to workers as per various statutes like the Factories Act 1948, Building & Construction Workers Regulation (BOCWR), etc. and, whenever collective measures are not feasible or are insufficient, provide and maintain personal protective equipment and clothing in line with the requirement as per OISD-STD-155 (Part I & II) on Personnel Protective “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 4 SAFETY PRACTICES DURING CONSTRUCTION Equipment. They should also provide access to workers to occupational health services. educate workers about their right and the duty at any workplace to participate in ensuring safe working conditions to the extent of their control over the equipment and methods of work and to express views on working procedures adopted as may affect health, safety and environment. xi) ensure that except in an emergency, workers unless duly authorised, should not interfere with, remove, alter or displace any safety device or other appliance furnished for their protection or the protection of others, or interfere with any method or process d adopted with a view to avoiding accidents and injury to health. ite xii) ensure that workers do not operate or interfere with plant and equipment that they have not been duly authorised to operate, maintain or use. m xiii) ensure that workers do not sleep, rest or cook etc in dangerous places such as scaffolds, railway tracks, garages, confined Li spaces or in the vicinity of fires, dangerous or toxic substances, machines or vehicles and heavy equipment etc. xiv) y obtain the necessary clearance/permits as required and specified er by owner. Arrangement for drinking water, toilet facilities, a creche and in transport arrangement etc. to be provided as per statutory requirement. ef xv) deploy a safety officer at site as per the requirement of Factory Act 1948/ Building & Construction Workers Regulation (BOCWR)/ R Criticality of the job. xvi) ensure that all employees/workmen undergo medical examination h as required under the law or under the contract provision and ar keep a record of the same. xvii) obtain the police verification of the workers/ supervisors arranged ig by him and the same is to be submitted to the owner. xviii) not permit any employee/workmen/visitor to enter the work area al under the influence of alcohol or any drugs. um 4.2 GENERAL DUTIES OF OWNERS N 4.2.1 Owners should: i) co-ordinate or nominate a competent person to co-ordinate all activities relating to HEALTH, SAFETY AND ENVIRONMENT on their construction projects; ii) inform all contractors on the work site / project of special risks to HEALTH, SAFETY AND ENVIRONMENT; iii) ensure that executing agency is aware of the owner's requirements and the executing agency's responsibilities with respect to HEALTH, SAFETY AND ENVIRONMENT practices before starting the job. 5.0 SAFETY PRACTICES AT WORK PLACES 5.1. GENERAL PROVISIONS “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 5 SAFETY PRACTICES DURING CONSTRUCTION 5.1.1 All openings and other areas likely to pose danger to workers should be clearly indicated and accident prevention measures taken as required. The working area should be clearly de-marketed to keep the workers in that area only. 5.1.2 Workers & Supervisors should use the safety helmet and other requisite Personal Protective Equipment according to job & site requirement as per OISD-STD-155 (Part I & II). They should be trained to use personal protective equipment including their limitations. 5.1.3 Never use solvents, alkalis and other oils to clean the skin. 5.1.4 Lift the load with back straight and knees bent. The contractor shall d ensure at his construction site, no worker lifts by hand or carries ite overhead or over his back or shoulders any material, article, tool or pipelines exceeding in weight as per The Factory Act 1948 / Rule 38 of Building & Construction Workers Regulation (BOCWR), unless aided by m another worker or device. 5.1.5 Ensure the usage of correct and tested tools and tackles. Don't allow Li the make shift tools and tackles. Also the tools should be suitable for a particular job and rated accordingly. 5.1.6 y No loose clothing should be allowed while at construction site. er 5.1.7 Start work only after proper authorization viz Work permit etc. 5.1.8 Job safety analysis to be done for all critical works. in 5.1.9 Hydra should not be used for transportation of hook loaded materials. ef 5.1.10 Rope ladders should not be used at construction sites. R 5.2 MEANS OF ACCESS AND EGRESS h Adequate and safe means of access (atleast two, differently located) to and ar egress from all workplaces should be provided. Same should be displayed and maintained. Escape routes should be marked prominently in workers friendly ig language. The escape routes should not be blocked at any point of time and same to be made understand to the workers. al um 5.3 HOUSEKEEPING 5.3.1 General Housekeeping shall be carried out by the contractor and he will N ensure; i) proper storage of materials and equipment; ii) removal of scrap, inflammable material, waste and debris at appropriate intervals including slippery materials. (construction sand on road, oil/ lubricants, resins, etc.). iii) to provide containers for segregation of disposal of debris at required places and regular cleaning of the same. 5.3.2 Removal of loose materials, which are not required for use, to be ensured. Accumulation of these at the site can obstruct means of access to and egress from workplaces and passageways. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 6 SAFETY PRACTICES DURING CONSTRUCTION 5.3.3 Workplaces and passageways, that are slippery owing to oil, grease or other causes, should be cleaned up or strewn with sand, sawdust, ash etc. 5.3.4 All surplus earth and debris are removed/disposed off from the working areas to officially designated dumpsites. The debris like plastics, packing material, rubber items should not be allowed to burn. Trucks carrying sand, earth and any pulverized materials etc. in order to avoid dust or odour impact, shall be covered while moving. 5.4 PRECAUTIONS AGAINST THE FALL OF MATERIALS & PERSONS AND COLLAPSE OF STRUCTURES d ite 5.4.1 Precautions should be taken such as the provision of fencing, look-out men or barriers to protect any person against injury by the fall of materials, or tools or equipment being raised or lowered. m 5.4.2 Where necessary to prevent danger, guys, stays or supports should be used or other effective precautions should be taken to prevent the Li collapse of structures or parts of structures that are being erected, maintained, repaired, dismantled or demolished. 5.4.3 y All openings through which workers are liable to fall should be kept er effectively covered or fenced and displayed prominently. 5.4.4 SOP of crane operation should be adhered to. The crane jacks/legs in should be parked on compacted surface to avoid tilting. ef 5.5 PREVENTION OF UNAUTHORISED ENTRY R 5.5.1 Construction sites located in built-up areas and alongside vehicular and pedestrian traffic routes should be fenced to prevent the entry of h unauthorised persons. ar 5.5.2 Visitors should not be allowed access to site(s) unless accompanied by or authorised by a competent person. All authorized visitors should report at the site office. Contractor shall provide visitor’s helmet (helmet ig with visitor sticker) and other PPEs like Safety Shoe, reflective jacket, al respiratory protection etc. as per requirement of the site. All the workers to have photo IDs including the staff of vehicles used in the job. um 5.6 FIRE PREVENTION AND FIRE FIGHTING N 5.6.1 All necessary measures should be taken by the executing agency and owner to: i) avoid the risk of fire; ii) control quickly and efficiently any outbreak of fire; iii)bring out a quick and safe evacuation of persons. iv)Inform unit/fire station control room, where construction work is carried out within existing operating area. v) DMP should be in place for the same. 5.6.2 Combustible materials such as packing materials, sawdust, greasy/oily waste and scrap wood or plastics should not be allowed to accumulate in workplaces but should be kept in closed metal containers in a safe place. To be disposed periodically away from site at designated place and assigned manner. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 7 SAFETY PRACTICES DURING CONSTRUCTION 5.6.3 Places where workers are employed on works prone to danger of fire should be provided with: i) suitable and sufficient fire-extinguishing equipment, which should be easily visible and accessible; ii) an adequate water supply at sufficient pressure meeting the requirements of various OISD standards. iii) required PPEs. 5.6.4 To guard against danger at places having combustible material, workers should be trained in the action to be taken in the event of fire, including the use of means of escape. 5.6.5 At sites having combustible material, suitable visual sign boards should d be provided to indicate clearly the direction of escape in case of fire. ite 5.6.6 Means of escape should be kept clear at all times. Escape routes should be frequently inspected and if possible marked in fluorescent colours particularly in high structures and where access is restricted. m Li 5.7 LIGHTING 5.7.1 Where natural lighting is not adequate, working light fittings or portable y hand-lamps should be provided at workplace on the construction site er where a worker will do a job. in 5.7.2 Emergency lighting should be provided for personnel safety during night time to facilitate standby lighting source, if normal system fails. ef 5.7.2 Artificial lighting should not produce glare or disturbing shadows. R 5.7.3 Lamps should be protected by guards against accidental breakage. 5.7.4 The cables of portable electrical lighting equipment should be of adequate size & characteristics for the power requirements and of h adequate mechanical strength to withstand severe conditions in ar construction operations. 5.7.5 For temporary lighting connection, mostly neutral and phases are ig connected and insulation tapes are provided. It is better to stagger the neutral and phase connection so that even if the tape gets removed from al the joints, there will be no short circuit/ spark between neutral and phase due to staggering of neutral and phase. um 5.7.6 All the temporary lighting/ machine connections are to be provided from a three core cable for better safety. N 5.8 PLANT, MACHINERY, EQUIPMENT AND HAND TOOLS 5.8.1 General Provisions i) Plant, machinery and equipment including hand tools, both manual and power driven, should: a) be of proper design and construction, taking into account health, Safety and ergonomic principles. b) be maintained in good working order; c) be used only for work for which they have been designed. d) be operated only by workers who have been authorised and given appropriate training. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 8 SAFETY PRACTICES DURING CONSTRUCTION e) be provided with protective guards, shields or other devices as required. ii) Adequate instructions for safe use should be provided. iii) Standard operating procedures should be established and used for all plant, machinery and equipment. iv) Operators of plant, machinery and equipment should not be distracted while work is in progress. v) Plant, machinery and equipment should be switched off when not in use d and isolated before any adjustment, clearing or maintenance is done. ite vi) Where trailing cables or hose pipes are used they should be kept as short as practicable and not allowed to create a hazard. m vii) All moving parts of machinery and equipment should be enclosed or Li adequately guarded. viii) Every power-driven machine and equipment should be provided with y adequate means, immediately accessible and readily identifiable to the er operator, of stopping it quickly and preventing it from being started again inadvertently. in ix) Operators of plant, machinery, equipment and tools should be provided ef with PPEs, including where necessary, suitable ear protection. R 5.8.2 Hand tools h i) Hand tools should be repaired by competent persons. ar ii) Heads of hammers and other shock tools should be dressed or ground to a suitable radius on the edge as soon as they begin to mushroom or crack. ig iii) When not in use and while being carried or transported, sharp tools should be kept in sheaths, shields, chests or other suitable containers. al iv) Only insulated or non-conducting tools should be used on or near live electrical installations. um v) Only non-sparking tools should be used near or in the presence of flammable or explosive dusts or vapours. N 5.8.3 Pneumatic Tools i) Operating triggers on portable pneumatic tools should be: a) so placed as to minimise the risk of accidental starting of the machine. b) so arranged as to close the air inlet valve automatically when the pressure of the operator's hand is removed. ii) Hose and hose connections for compressed air supply to portable pneumatic tools should be: “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 9 SAFETY PRACTICES DURING CONSTRUCTION a) designed and tested for the pressure and service for which they are intended; b) fastened securely on the pipe outlet and equipped with the safety chain, as appropriate. iii) Pneumatic shock tools should be equipped with safety clips or retainers to prevent dies and tools from being accidentally expelled from the barrel. iv) Pneumatic tools should be disconnected from power and the pressure in hose lines released before any adjustment or repair is made. 5.8.4 Electrical Tools i) Low voltage portable electrical tools should generally be used. d ii) All electrical tools should be earthed, unless they are "all insulated" or ite "double insulated" tools which do not require earthing. iii) All electrical tools should get inspected and maintained on a regular basis by a competent electrician and complete records kept. m iv) No temporary connected appliance shoud be left connected in the socket. Li Its plug should be immediately removed after use. 5.8.5 Engines y er i) Engines should: a) be installed so that they can be started safely and the maximum safe in speed cannot be exceeded. b) have controls for limiting speed. ef c) have devices to stop them from a safe place in an emergency. d) have their batteries top covered with insulating material. R e) have radiator fan covers in place. ii) IC engines should not be run in confined spaces unless adequate h exhaust ventilation is provided or the exhaust should be installed outside ar the confined place at suitable height. ig iii) When IC engines are being fuelled: al a) the engine should be shut off. b) care should be taken to avoid spilling fuel. um c) no person should smoke or have an naked light in the vicinity. d) a fire extinguisher should be kept readily available. iv) Secondary fuel reservoir should be placed outside the engine room. N 6.0 CONSTRUCTION ACTIVITIES The various common activities in construction are as under: Excavation Scaffolding, Platforms & Ladders Structural Work, Laying of Reinforcement & Concreting Road Work (Laying of roads) Cutting /Welding Working in Confined Space “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 10 SAFETY PRACTICES DURING CONSTRUCTION Proof/Pressure Testing Working at Heights Handling & Lifting Equipment Vehicle Movement Electrical Offshore Demolition Radiography Shot blasting/ spray painting d Work above water ite Work permit system as per requirement of OISD-STD-105 shall be followed for various construction activities. As regards the activities at work places including m grass root project sites if not covered under OISD-STD-105, owner shall develop a suitable methodology for execution of various construction activities under work Li permit system for safe execution of the works. The safe practices to be followed during the implementation of above construction activities are given below: y er 6.1 EXCAVATION in 6.1.1 All excavation work should be planned and the method of excavation and ef the type of support work required should be decided considering the following: R i) the stability of the ground including the chances of seepage of water; ii) the excavation will not affect adjoining buildings, structures or roadways; h iii) to prevent hazard, the Hydrocarbon lines, water, electrical and other ar above ground & underground public utilities should be shut off, re- routed or disconnected, if necessary; If such a presence is envisaged, ig clearance to be taken from respective competent authority/ person. iv) the position of culvert/bridges, temporary roads and spoil heaps should be determined; al v) a signed rough sketch of the excavation site to be prepared and made the workers understand um 6.1.2 Before digging begins on site, all excavation work should be planned and the method of excavation and the type of support work required should be decided based on good engineering practices and recorded. N 6.1.3 All excavation work should be supervised by a competent person. 6.1.4 Sites of excavations should be thoroughly inspected: i) daily, prior to each shift and after interruption in work of more than one day; ii) after every blasting operation; iii) after an unexpected fall of ground; iv) after substantial damage to supports; v) after a heavy rain, frost or snow; vi) when boulder formations are encountered. vii) for cracks in the nearby buildings or area as the excavation progresses and the same to be reviewed. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 11 SAFETY PRACTICES DURING CONSTRUCTION 6.1.5 Safe angle of repose while excavating trenches exceeding 1.5m depth upto 3.0m should be maintained. Based on site conditions, provide proper slope, usually 450,and suitable bench of 0.5m width at every 1.5m depth of excavation in all soils except hard rock or provide proper shoring and strutting to prevent cave-in or slides. 6.1.6 As far as possible, excavated earth should not be placed within one meter of the edge of the trench or depth of trench whichever is greater. 6.1.7 Don't allow vehicles to operate too close to excavated area. Maintain atleast 2m distance from edge of excavation or depth of trench whichever is greater. No load, plant or equipment should be placed or moved near the edge of any excavation where it is likely to cause its collapse and thereby endanger any person unless precautions such as the provision of d shoring or piling are taken to prevent the sides from collapsing. ite 6.1.8 Adequately anchored stop blocks and barriers should be provided to prevent vehicles being driven into the excavation. Heavy vehicles should m not be allowed near the excavation unless the support work has been specially designed to permit it. Li 6.1.9 If an excavation is likely to affect the stability of a structure on which persons are working, precautions should be taken to protect the structure from collapse. y 6.1.10 Barricade at 1m height (with red & white band/self glowing caution board) er should be provided for excavations beyond 1.0 m depth. Provide two entries/exits for such excavation through proper means. Lighting in arrangements to be made to avoid any accidental fall in the excavated portion even when work is not in progress. ef 6.1.11 Necessary precautions should be taken for underground utility lines like cables, sewers etc. and necessary approvals/clearances from the R concerned authorities shall be obtained before commencement of the excavation job. h 6.1.12 Water shall be pumped/ bailed out, if any accumulates in the trench. ar Necessary precautions should be taken to prevent entry of surface water in trenches. ig 6.1.13 During / after rains, the soil becomes loose. Take additional precaution against collapse of side wall. During rains excavation should be avoided. al 6.1.14 In hazardous areas, air should be tested to ascertain its quality. No one should be allowed entry till it is suitable for breathing. um 6.1.15 In case of mechanised excavation, precaution shall be taken to not to allow anybody to come within one meter of extreme reach of the mechanical shovel. This area of reach of mechanical shovel should be N marked / barricaded suitably. The mechanised excavator shall be operated by a well-trained experienced operator. When not in operation, the machine shall be kept on firm leveled ground with mechanical shovel resting on ground. Wheel or belt shall be suitably jammed to prevent any accidental movement of the machine. Suitable precautions as per manufacturer guidelines should be taken for dozers, graders and other heavy machines. 6.1.16 In case of blasting, follow strictly IS:4081-1986 & Indian Explosive Act and rules for storage, handling and carrying of explosive materials and execution of blasting operation. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 12 SAFETY PRACTICES DURING CONSTRUCTION 6.2 SCAFFOLDING, PLATFORMS & LADDERS System of tagging shall be followed to indicate status of `Fit-for-Purpose’ certification by a competent person for the scaffoldings. Green Tag shall indicate `Fit-for-Purpose’ whereas Red Tag shall indicate `Unfit-for-purpose’. Accordingly only Red Tag shall be displayed during Erection & Dismantling. All personnel engaged in erecting, using, dismantling scaffolds shall use full body safety harness with double lanyard with shock absorber connected with personal fall arrestor which should be secured to a properly designed anchor. 6.2.1 Scaffold related guidelines d ite General Requirements m Categories and Classification Li Most scaffolds fall into one of the four primary categories: Tube and coupler scaffold y System scaffolds e.g. Cup lock, Ring lock, H frame scaffold er Suspension(or Suspended) scaffold Mobile scaffold in Special scaffold ef Scaffolds are classified according to their intended use as: R Light duty Medium duty (General Purpose) h Heavy duty ar Type of Scaffolding Load duty Light Medium Heavy/Special ig Maximum Safe load in 75 150 225 300 450 600 al Kg/m2 Tubular with clamps Max. bay length (distance 2.7 2.2 1.8 1.4 1.0 0.8 um Cup / Ring lock between two verticals) in 2.5 2.0 1.5 1.25 1.0 NA Meter N Conditions where special scaffolding procedure is required: 1. Height of the scaffolding is more than 30 meters. 2. Scaffolding is special in nature/ type: cantilever more than 1.5 meters, bridge more than 4 meters, scaffolding for machine/ equipment maintenance requiring frequent modifications, offshore scaffold, hanging scaffold; wooden scaffold (for specific use e.g. cooling tower), etc. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 13 SAFETY PRACTICES DURING CONSTRUCTION For all such cases, but not limited to, in addition to checklist, a plant specific procedure cum checklist based on additional risk is to be d prepared & validated by a competent person (example: procedure for ite erection/ dismantling shall be prepared and followed. If need felt, help from Engineering Cell/Third Party may be taken for checking proposed scaffold in respect of design and load carrying capacity etc.). m Specifications of Scaffolds Li Applicable to all Scaffolds y 1. All elevated structures/ working platform areas should be guarded on er all sides. in 2. Railings and toe boards should be provided on the platform. ef 3. Scaffolds shall be designed to support at least 4 times the anticipated R weight of Men, material and wind force. 4. Make certain that all scaffolds are in plumb and level at all times. h ar 5. Scaffolds shall be secured from tipping when the scaffold height exceeds four times its minimum base dimension. ig 6. Scaffolds must be constructed at least 3 planks wide unless location al makes this physically impossible. um 7. Landing platform should be provided at every 9 meter of height or less. N 8. The members of scaffolds should extend at least 6" on either ends but not more than 12". They should be fastened on both ends and laid tight by clamps. 9. All scaffoldings having height to base ratio more than 4 shall be secured firmly with permanent structure in X and Y direction at least every 6 meters. 10. Scaffold which spread to 20 meter or more should have two accesses preferably opposite side. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 14 SAFETY PRACTICES DURING CONSTRUCTION 11. Plastic Checklist holder with red marked to be used as a “Not Fit-for- Purpose” warning signboard and Green colour combined checklist to be used as “Fit-for-Purpose” signboard. 12. Keep distance of at least 150mm between high temp Pipelines or equipment and scaffolding. 13. Safe distance from overhead electrical lines to be maintained as per Site electrical safety procedures. Applicable to Tube-and-coupler scaffold d 1. Tube and coupler scaffolds over 30 meter in height must be Designed ite by a competent professional engineer (who by extensive knowledge, training, and experience have successfully demonstrated his ability to m carry out scaffold design and load calculations). 2. Maximum height of first horizontal member (Ledger) of scaffolds from Li the Ground shall be 2.2 meters. Lower lift can be considered for heavy loads depending upon the scaffold design. When scaffold is more than 6 meter height for carrying heavy load, kicker lift should be provided at a height of 150mm from ground. y er 3. The top rail shall be at height of 900-1200 mm and Mid rails must be in installed approximately halfway between the top rail and the platform surface. Toe boards (150mm) should be securely attached to the ef working platform. Toe boards are generally applicable to working platform and not for landing platforms. R 4. The bay length & width depends on the height and the load to be h carried by the scaffold. ar 5. Bracings shall be fitted up to full height of scaffold. ig 6. Standards should be joined having overlap of min 600 mm using three equally spaced swivel clamps or end to end using sleeve/pin type al coupler. um 7. Ledgers should be joined having overlap of min 600 mm using three equally spaced swivel clamps or end to end using sleeve coupler. N 8. Base plate 150 x 150 x 6mm shall be used to support all vertical pipes of Scaffolds. 9. Sole plate shall be used at all unpaved area to support base late. 10. Scaffolding platform Grating shall be tied with clamp at both ends, and scaffolding platform Grating shall not overhang more than 150 mm and shall be at least 150 mm away from hot surface. 11. Every scaffold shall be provided with certified ladder and extending its free end shall be above platform by 1000 mm/ four rungs. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 15 SAFETY PRACTICES DURING CONSTRUCTION Applicable to Mobile scaffolds 1. Attach castors with plain stems to the panel or adjustment screw by pins or other suitable means. 2. Apply castor brakes/lock at all times when scaffolding is not being moved. 3. Do not ride rolling scaffoldings. 4. Remove all material and equipment from platform before moving d scaffolding. ite 5. Do not try to move rolling scaffolding without sufficient help. Watch out for holes protrusions in the floor and for overhead obstructions. m 6. Do not use brackets on rolling scaffoldings without first considering Li the overturning effect. Design Criteria y er All types of scaffolds shall be strong enough of carrying and transmitting all types of loads to the ground. All scaffolds shall be in adequately secured, stiffened, both longitudinally and transversely. ef Scaffolding determines as per the requirement and use of scaffold such as: R o Purpose of scaffolding h o Loading on scaffold platform ar o Required height ig o Sufficient work place al o Surrounding environment um Storage and inspection of materials N All scaffolding material shall be stored at designated location to protect them from adverse environment conditions such as corrosion, weather. Storage racks/ Locations/ areas shall be clearly identified. Storage facility of scaffold material shall be properly constructed for its stability and load bearing capability. Steel pipes and scaffolding platform Grating shall be stacked horizontally according to length. Fittings, Couplers shall be stored in separate bins. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 16 SAFETY PRACTICES DURING CONSTRUCTION Defective material shall be removed from site. Scaffolding material such as tubular, planks, clamps etc. shall be inspected annually for contractor owned material by contractor. The visual inspection shall cover 100% scaffold materials. Transportation and handling of scaffolding material Make sure that scaffold pipe shifting done in vehicle of appropriate d length. ite Special safety care to be taken while shifting or lifting pipes manually. m Rope and pulley should be used to lift pipe from height. Li Safety requirements y er A risk assessment to access scaffold hazards through inspection and work in method statement for relevant work activities shall be made before erecting, dismantling, moving, or modifying scaffold. Examples of hazards to be ef considered include the following: R Working at/from heights. The presence of nearby electrical lines or process equipment (e.g. hot line, h vents, drains, etc.). Necessary safety distances shall be maintained as ar specified in site level electrical safety procedure. Possible emergency scenario, escape routes and responses. ig al The condition and loading of working surfaces /platform /scaffold pipes and other components or loose material such as clamps/ bolts on the working um platforms. The presence and activity of other people and equipment in the vicinity of the work. N The weather (Heavy rain, high wind velocity-more than 20 knots, etc). Erection during dark hours. Scaffold collapse. Manual task (Manual Material Handling). Access and egress during normal and emergency condition. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 17 SAFETY PRACTICES DURING CONSTRUCTION The effect of heavy equipment movement in close vicinity such as within 4 meters to be considered for direct hit and sagging of land in case of unpaved area. This assessment is a part of the work permit process but should also be extended to the specific job planning of the crew performing the work. Appropriate actions shall be taken to mitigate the hazards identified during the assessment. Fall protection when erecting, dismantling, and modifying scaffolds shall be under the direction of a competent person (Scaffold Supervisor). Scaffold d erectors (Scaffolder) shall use personal fall-protection systems that provide ite continuous fall protection while erecting, dismantling or modifying scaffolds unless the determination is made by a competent person that fall protection is m not feasible or it creates a greater hazard. Fall protection can be accomplished through the use of adequate anchorages that are independent Li of the scaffold or by using scaffold systems and components that are approved by the manufacturer as adequate anchorages. Employees/workmen shall use appropriate fall-arrest equipment. y er The footing for supported scaffolds shall be sound, rigid, and capable of supporting the maximum intended load, including the weight of the scaffold. in ef Scaffold platform grating shall be fastened on both ends and laid tight by scaffold clamps/couplers. R Manufacturer’s guidelines for proprietary scaffolds (e.g. Cup lock, ring lock, H h frame, Insulating modular scaffolds) shall be followed unless a competent ar person approves the variance and provided the variance complies with applicable regulations and generally accepted scaffold engineering practices. ig Proprietary/special scaffold manufacturer’s guidelines for erection and al inspection should be available with users, and with plant maintenance um engineer for reference. The following safe practices with respect to scaffolds shall be followed: N There shall be firm foundation for all scaffoldings. All scaffolding shall be made of sound material. Scaffolding material shall be inspected and used, only if found in good condition. Avoid using equipment whose strength is not known. Provide adequate Base for scaffolding posts. Metal base plate is used under all upright or standard scaffoldings. Correct type of couplers shall be used for all connections. Use right angle couplers for joining vertical to horizontal members and swivel type couplers for joining bracing with ledgers. For joining vertical load bearing members (standards), “joint pin” type couplers can also be used. The couplers shall be of a structural “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 18 SAFETY PRACTICES DURING CONSTRUCTION metal, such as drop-forged steel, malleable iron, or structural grade aluminum (use of gray cast iron is prohibited). Plumb and level scaffoldings as erection proceeds, so that braces will fit without forcing. Fasten all braces securely. Where scaffoldings are erected above walkways or work areas, the space between toe board and railing should be screened (e.g. Safety net, Metal sheets). Whenever work is being done over men who are working on scaffolding, d overhead protection should be provided on the scaffolding. ite Restrain free-standing scaffolding towers from tipping by guying or other means. m A safe and convenient means of access shall be provided to the platform Li level. Means of access may be a portable ladder, fixed ladder, ramp or runway or stairway. The ladder shall be so installed that there supporting y member (pipe) is just below ladder rung. This is to avoid tripping hazard, er especially while using the ladder. in During erection, the ladder shall be installed as early as practicable, but not later than first two horizontal members (Ledgers). This is to facilitate ef Scaffolder while erecting the scaffold. R During erection/ dismantling, scaffolder shall use ‘T’ steps to minimize risk of accidental fall/ slip. h Ladder should be provided with tie rods/studs at top and bottom rungs and ar secured to scaffolding with ladder clamps, at least 2 locations for a ladder of length up to 4 m & at 3 locations for more than 4 m long ladder. ig The horizontal member/ ledger on which ladder is to be fixed, must be al clamped to two subsequent standard using fixed clamps. um Do not cantilever or extend putlogs / trusses as side brackets, without thoroughly considering the loads to be applied. N Do not climb scaffold using cross braces. Do not use ladders or makeshift devices on top of scaffoldings to increase the height. Have at least 12” overlap and 6” extension beyond centerline of support or cleat at both ends to prevent sliding. Do not allow unsupported ends of planking to extend an unsafe distance beyond supports. Planks shall be non-greasy and free from defects. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 19 SAFETY PRACTICES DURING CONSTRUCTION Access to working platform shall be suitably protected against inadvertent fall by providing swing members/ swing gate or chains. When scaffolding is no longer required, request for dismantling of scaffold shall be sent to scaffolding supervisor through work permit. Scaffold shall be removed from top bracings. Ties, rackers etc. should not be removed from section lower than the one which is being dismantled. Do not throw or allow falling to ground any scaffold member, board or fittings. d ite Dismantled scaffold material shall be neatly stacked, away from the site until whole of scaffold has been dismantled. m 6.2.2 Metal as material of construction Li i) A scaffold should be provided and maintained or other equally safe and suitable provision should be made where work cannot safely y be done on or from the ground or from part of a building or other permanent structure. er ii) Scaffolds should be provided with safe means of access, such as in stairs, ladders or ramps. Ladders should be secured against inadvertent movement. ef iii) Every scaffold should be constructed, erected, properly secured/ tied and maintained so as to prevent collapse or accidental R displacement during erection, while in use, in idle state or dismantling. h iv) Every scaffold and part thereof should be constructed : ar (a) in such a way so as not to cause hazards for workers during erection and dismantling; (b) in such a way so as guard rails and other protective devices, ig platforms, ladders, stairs or ramps can be easily put together; al (c) with sound material and of requisite size and strength for the purpose for which it is to be used and maintained in a proper um condition. v) Boards and planks used for scaffolds should be protected against splitting. N vi) Materials used in the construction of scaffolds should be stored under good conditions and apart from any material unsuitable for scaffolds. vii) Couplers should not cause deformation in tubes. Couplers should be made of drop forged steel or equivalent material. viii) Tubes should be free from cracks, splits and excessive corrosion and be straight to the eye, and tube ends cut cleanly square with the tube axis. ix) Scaffolds should be designed for their maximum load as per relevant codes. x) Scaffolds should be adequately braced. “OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of OISD Standards/Guidelines.”  OISD/DOC/08/2023/09 OISD – GDN – 192 Page No. 20 SAFETY PRACTICES DURING CONSTRUCTION xi) Scaffolds which are not designed to be independent should be rigidly connected to the building at designated vertical and horizontal places. xii) A scaffold should never extend above the highest anchorage to an extent which might endanger its stability and strength. xiii) Loose bricks, drainpipes, chimney-pots or other unsuitable material should not be used for the construction or support of any part of a scaffold. xiv) Scaffolds should be inspected and certified: (a) before being taken into use; d (b) at periodic intervals thereafter as prescribed for different types of scaffolds; ite (c) after any alteration, interruption in use, exposure to weather or seismic conditions or any other occurrence likely to have affected their strength or stability. m xv) Inspection should more particularly ascertain that: Li (a) the scaffold is of suitable type and adequate for the job; (b) materials used in its construction are sound and of sufficient strength; (c)