IS 9494:1980 is the Indian Standard (BIS) for concrete formwork - code of practice for safety. This code provides safety guidelines for the design, fabrication, erection, and stripping of concrete formwork. It specifies minimum loads, material requirements, and procedural checks to ensure the stability of temporary structures and the safety of workers on construction sites.
Lays down safety requirements for the design, erection, use, and dismantling of concrete formwork.
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Minimum Horizontal Load for Bracing | Not less than 2% of the total vertical load at that level. | Not less than 2.5% of the characteristic vertical dead load. | AS 3610.1:2018 |
| Minimum Construction Live Load (on working platforms) | 75 kg/m² (approx. 0.75 kPa) for light duty access. | 1.0 kPa for areas accessible to personnel only. | AS 3610.1:2018 |
| Primary Basis for Formwork Stripping | Time-based tables based on ambient temperature and cement type. | Concrete achieving a specified minimum compressive strength (e.g., 15 MPa for many suspended elements). | AS 3610.1:2018 |
| Inspection Stages | 1) Before placing reinforcement, 2) Before placing concrete, 3) During concreting. | 1) Immediately prior to concrete placement, 2) During placement, 3) Immediately after placement. | OSHA 1926.703(b)(1) |
| Prop Spacing | Generally recommends spacing not to exceed 1.0 m. | Not specified; determined by design calculations based on loads and member capacity. | General practice in BS 5975 / AS 3610.1 |
| Design Responsibility for Formwork | To be designed by a responsible person, with drawings available on site. | Must be designed and documented by a qualified engineer, with independent design checks for complex schemes. | BS 5975:2019 |