Specification for Higher Capacity Dry Powder Fire Extinguisher (Trolley Mounted)
1999 Edition

As per Clause 5.1 and Table 1, the extinguisher components must be made from specified materials such as mild steel sheets for the body (IS 1079, IS 2041, IS 2062), leaded tin bronze or seamless mild steel tubes for the neck ring, brass or plastic for the nozzle, and acid-alkali resistant rubber for washers (IS 5382). These materials ensure durability, compatibility, and compliance with safety standards.

The extinguisher body must withstand a design pressure not exceeding 15 kgf/cm² (1.5 MN/m²) at 27 ± 5°C. The minimum wall thickness is calculated considering a corrosion allowance of 0.5 mm using the formula: t = (p × Do) / (2 × f × j – p) + 0.5 mm, where p is design pressure, Do is outside diameter, f is allowable stress, and j is the weld joint factor. The body should be constructed from weldable carbon steel or austenitic stainless steel with appropriate joint specifications.

Dry powder is expelled by pressure generated from a compressed or liquefied gas cylinder attached to the extinguisher or a gas cartridge on the cap, providing a continuous jet. The discharge hose must be braided rubber or PVC with a nominal bore of 19 mm, having a minimum length of 3 meters for 25 kg units and 5 meters for 50 kg and 75 kg extinguishers. Nozzles are trigger-operated to facilitate easy and controlled discharge.

Recommended coatings include epoxy powder coatings with a minimum thickness of 0.050 mm applied internally and externally. Alternatively, internal surfaces may have plastic or rubber linings at least 0.5 mm thick. Earlier approved options include zinc or lead-tin alloy coatings (minimum 0.025 mm thickness, with at least 10% tin) applied via hot-dipping or electroplating. External phosphating is also permitted as per IS 3618. Coating thickness measurements follow IS 3203 standards.

Each extinguisher must bear permanent markings including the manufacturer's name or trademark, operating instructions, the label 'Dry Powder Extinguisher,' capacity in kilograms, a notice to recharge after use, pressure test rating (3.0 MN/m²), applicable fire class letters (A, B, C), year of manufacture, working and design pressures, gas cartridge capacity, and gas cylinder capacity with filling ratio. The extinguisher should be painted fire red (IS 5 shade No. 536) for visibility.

The wheeled carriage is designed with the extinguisher body elevated a minimum of 10 cm above ground for 25 kg units, and 20 cm for 50 kg, 75 kg, and 100 kg units. Wheels feature solid rubber tyres sized 200×50 mm for 25 and 50 kg extinguishers, and 300×75 mm for 70 kg units. The steel frame provides stable vertical support and ease of mobility. All parts except the body are coated with primer and two finishing paint layers conforming to IS 2932.

Yes, IS 10658 includes optional provisions for the ECO Mark, administered by BIS under the BIS Act, 1986, in cooperation with the Ministry of Environment and Forests. Compliance requires manufacturers to obtain environmental clearances under relevant pollution control acts and meet additional eco-friendly criteria. The ECO Mark, combined with the ISI Mark, signifies environmental compliance but is voluntary and supplemental to standard ISI certification.