F401 Guide to Safety Procedures for Vertical Concrete Formwork SCAFFOLDING, SHORING AND FORMING INSTITUTE, INC. 1300 SUMNER AVENUE, CLEVELAND, OHIO 44115 (216) 241-7333 F401 F O R E W O R D The “Guide to Safety Procedures for Vertical Concrete Formwork” has been prepared by the Forming Section Engineering Committee of the Scaffolding, Shoring & Forming Institute, Inc., 1300 Sumner Avenue, Cleveland, Ohio 44115. It is suggested that the reader also refer to other related publications available from the Scaffolding, Shoring & Forming Institute. The SSFI welcomes any comments or suggestions regarding this publication. Contact the Institute at the following address: Scaffolding, Shoring and Forming Institute, 1300 Sumner Ave., Cleveland, OH 44115. i F401 CONTENTS PAGE Introduction ........................................................................................ 1 Section 1 - General................................................................................ 2 Section 2 - Erection of Formwork......................................................... 2 Section 3 - Bracing................................................................................ 3 Section 4 - Walkways/Scaffold Brackets.............................................. 3 Section 5 - Special Applications........................................................... 4 Section 6 - Inspection............................................................................ 4 Section 7 - Concrete Placing................................................................. 5 Section 8 - Stripping Formwork ........................................................... 5 Section 9 - Glossary of Vertical Forming Terminology........................ 5 Appendix: Some Common Causes of Form Failures ........................... 14 ii F401 I N T R O D U C T I O N Because of the widespread and constantly growing use of forming in construction today, it is vital that it be used properly and safely. At present, the subject of forming is not covered in most standard reference works on safe construction practices; therefore, two objectives were established before preparing this guide: 1. To fill the need for information on forming and the safe and proper use thereof and - 2. To provide a guide to various federal, state and local authorities having jurisdiction over construction work in developing their own codes. However, the information and recommendations contained herein do not supersede any applicable federal, state or local code, ordinance or regulation. Safety precautions prescribed by OSHA and other government agencies should be followed at all times and persons working with forming equipment should be equipped with requisite safety devices. The procedures outlined in this guide describe conventional procedures for erecting and dismantling forming systems. However, equipment and forming systems differ, and accordingly, reference must always be made to the instructions and procedures of the particular manufacturer or supplier whose equipment is being used. Since field conditions vary and are beyond the control of the Institute and its members, safe and proper use of this equipment is the responsibility of the user and not the Institute or its members. 1 F401 SECTION 1 GENERAL 1.1 All form components and/or hardware must be kept clean, and if appropriate, lubricated to 1.4 The forming layout shall be prepared or insure proper performance and to allow for approved by a person qualified to analyze the proper inspection. loadings and stresses which are induced during the construction process. The layout shall be at 1.2 All form components must be inspected the jobsite. regularly for damage or excessive wear. Equipment found to be in these conditions must 1.5 Forming installation and pouring procedures be replaced immediately and not re-used. must comply with safe practices and with the requirements of the law and governmental 1.3 Field repair of modular formwork regulations, codes and ordinances. components (other than plywood repairs) must not be undertaken without consulting the manufacturer’s qualified representative. SECTION 2 ERECTION OF FORMWORK 2.1 Do not deviate from layout drawings when Follow manufacturer’s/supplier’s recommended erecting formwork without the approval of a procedures concerning capacity and use of lifting qualified designer. hardware and crane. 2.2 Be certain that all wall ties are in place and 2.6 A minimum of two tag lines must be used to secured as per manufacturer’s recommendations. control movement of crane-handled formwork. Do not weld, bend or otherwise alter wall ties as Do not allow personnel on or directly under any it may seriously reduce their strength. gang form while it is being moved or suspended in air. 2.3 Adequate temporary bracing must be in place while initially setting formwork. Assure 2.7 Do not erect gang forms when jobsite wind that formwork is properly braced and stabilized conditions prevent safe maneuvering of gangs. against wind and other external forces. Assure that all rigging connections are properly made in accordance with safe practices and 2.4 Safe working platforms must be installed as procedures. per applicable safety standards and as stated in Section 5 herein. 2.8 Formwork should be adequately braced, re- anchored, or otherwise secured prior to releasing 2.5 When gang forming, lifting devices must be lifting mechanism. properly spaced and securely attached as per manufacturer’s recommendations. Rigging must 2.9 Wall forms must not be erected so as to be arranged so that any one lifting bracket is not support deck concrete loading unless the wall overloaded and that lifting cables are not at forms are a designed part of the deck support excessive angles, which will reduce allowable system. loads. Spreader beams with load equalizers are recommended for all but simple two point lifts. 2 F401 SECTION 3 BRACING 3.1 Aligners (alignment devices, plumbing safe support of the imposed brace loads. The struts) are considered only as alignment devices responsibility for adequate anchorage of braces with no provisions for withstanding concrete should be assigned only to those personnel with pressure or any portion thereof. Maintain forms sufficient experience to assure sound judgement. plumb during pour to ensure that aligners are not supporting or stabilizing concrete pressures. 3.5 Before removing braces, assure that the concrete has attained sufficient strength to safely 3.2 Braces used to withstand concrete pressure support the imposed load at support locations. must be designed by a qualified formwork designer. 3.6 Do not exceed the rated load of the braces. 3.3 Unless specified, wind loading and other 3.7 Inspect installed braces immediately after external lateral loads are not considered in the installation for correctness of spacing and proper manufacturer’s layout drawings. attachment device. 3.4 The adequacy of stakes, dead-men, sills, anchor-bolts, etc., must be determined to assure SECTION 4 WALKWAY SYSTEMS 4.1 All walkway systems must be properly 4.6 When deemed appropriate by the competent positioned, spaced and fastened as per person, scaffold planks must be nailed and manufacturer’s specifications and all applicable clinched, bolted or otherwise positively secured safety regulations. against dislodgement from effects of wind, weather, gang form lifting operations or the like. 4.2 Walkway systems must be in place along the Bolt heads and nails must be driven flush with upper level of formwork. Workers must never tops of planks to prevent tripping hazards. attempt to walk or stand on top of forms. 4.7 All scaffold bracket platforms must be 4.3 Scaffold brackets must be attached with the equipped with guardrails, midrails and toeboards manufacturer’s recommended connectors. Never along all open sides and ends and be maintained use substitutes or make-shift devices. Never secure and in good condition at all times. hang brackets from wall ties after removal of Guardrails must be of at least 2 x 4 nominal sized forms. lumber, with minimum 1 x 6 or 2 x 4 nominal midrails, with toeboards at least 4 inches high, 4.4 All walkway platforms must utilize at least supported by 2 x 4 nominal lumber uprights two (2) planks laid side by side, and must spaced not more than 8 feet apart, or must be of overlap their support ledger by not less than 6 other materials providing equivalent or greater inches. Unsupported ends of scaffold planks strength and protection. must not project more than 12 inches past their support ledger. 4.8 Maximum spacing between scaffold brackets is eight feet. Never exceed this distance unless 4.5 Scaffold planks must be minimum 2 inch x the walkway system has been specifically 10 inch nominal lumber and must be scaffold designed for a greater distance. Follow grade as recognized by approved grading rules manufacturer’s recommendations as to loading for the species of lumber used, or must be of and spacing of scaffold brackets. Unless materials having equivalent or greater strength. designed otherwise, scaffold brackets are Scaffold planks must safely support a minimum designed to support a maximum load of 25 of 25 pounds per square foot over a maximum pounds per square foot when spaced on 8 foot span of 8 feet. centers. Scaffold brackets are not designed for 3 F401 the additional loads imposed from stacking rebar that their weight while being used can effect the or placing other equipment on walkways. strength or stability of the scaffold and formwork. 4.9 Always brace and/or otherwise secure forms and scaffold