Specification for Industrial Safety Helmets (Bilingual)
1984 Edition

According to IS 2925 Part B, helmet shells must be made of non-metallic materials that comply with flammability resistance standards, including no flame continuation beyond five seconds after flame removal as per Appendix F. Water absorption should be limited to 5% by mass (Appendix H). Common materials include fiberglass, thermoplastics, or composite substances. For the harness, including headbands and anti-concussion elements, materials must be sweat-resistant, non-irritating, and should not cause skin ailments. Typical materials are cotton blends, synthetic sweat-absorbing fabrics, or soft plastics, ensuring comfort, safety, and durability.

Impact resistance testing involves mounting the helmet on a wooden headform specified by IS 7692:1975. A 500 g plumb bob with a conical steel tip (36° included angle, tip radius ≤ 0.5 mm) is dropped freely from a height of 3 meters vertically onto the helmet's crown. Post-impact, the helmet is inspected for perforations, dents, part failures, cracks, or material separation. Penetration resistance testing, conducted within one minute following the shock absorption test, requires no penetration to reach the headform, with maximum dent depth limited to 10 mm and no part failure or deformation that would permit the helmet to slip off. Shock absorption tests ensure transmitted force does not exceed 5 kN after conditioning at varied temperatures and water exposure.

IS 2925 Part B mandates chin straps to have a minimum width of 19 mm, be securely attached to the helmet shell, and equipped with a permanent fastener for tension adjustments. They must pass performance criteria outlined in Appendix C, covering strength, durability, and wearer comfort. Nape straps may be integral or connected to the headband, must be adjustable, and have a minimum vertical depth of 115 mm as measured according to the standard. Both straps ensure the helmet remains firmly positioned on the wearer's head to prevent displacement during impacts.

The standard requires helmet shells to pass flammability tests where the shell must not continue to burn or emit flames for more than five seconds after flame removal, as detailed in Appendix F. Additionally, heat resistance tests per Clause 8.6 and Appendix J subject the helmet shell to elevated temperatures (typically between 250°C and 300°C) for about four minutes. The shell must not distort, separate, or soften during or after this exposure, ensuring the helmet maintains its protective function under fire conditions.

Helmets must bear indelible markings either directly on the shell or on securely affixed labels including clear fit instructions, warnings regarding impact energy absorption and the necessity to replace helmets after severe impact, and advisories against any structural alterations to maintain protective efficiency. Manufacturer details such as name or trademark and helmet size or range must also be clearly marked. Optionally, helmets may display the ISI Certification Mark indicating compliance with BIS standards. These provisions ensure traceability, user awareness, and conformity to safety requirements.