Specification for portable fire extinguishers, dry powder (cartridge type)
1999 Edition

The standard specifies materials for each component of cartridge-type dry powder extinguishers. The body is made from mild steel sheets complying with IS 513, IS 2062, and IS 6240. The inner shell can be mild steel (IS 513) or plastic (IS 7328). Neck rings use leaded tin bronze (IS 318 Grade LTB 2), brass forging (IS 6912 Grade FLB), or seamless mild steel pipes (IS 1239 Part 1). Caps are constructed from leaded tin bronze, brass, plastic, or stainless steel (IS 318, IS 6912, Annex B, IS 6529). Other parts such as springs, syphon tubes, nozzles, cartridges, hoses, and safety clips are made from materials like carbon steel, brass, aluminium alloys, and PVC/rubber as per their respective Indian Standards.

Performance evaluations include discharge tests requiring at least 85% mass discharge of dry powder at 27 ± 5°C, with the nozzle positioned 45° above horizontal. Minimum throw duration and maximum discharge times vary by extinguisher capacity (e.g., 8–10 seconds for 1-2 kg, 15–20 seconds for 5 kg, and 23–30 seconds for 10 kg units) with specified minimum throw ranges. Hydraulic pressure testing at 30 kgf/cm² for 2 minutes ensures integrity without leaks. Thread durability involves 100 screw/unscrew cycles without damage, followed by hydraulic pressure testing at 45 kgf/cm² for 1 minute and thermal cycling consisting of repeated exposure to 60 ± 1°C and 5 ± 1°C. The extinguisher must maintain performance and structural soundness throughout.

The internal surfaces must be coated with a lead-tin alloy containing at least 10% tin through hot-dipping, achieving a minimum coating thickness of 0.012 mm measured according to IS 3203. Alternatively, an epoxy polyester powder coating with a thickness of 0.050 mm or a plastic/rubber lining of at least 0.5 mm thickness may be used. External surfaces and components such as the inner shell, siphon tube, and springs (if made of mild steel) require the same corrosion protection. The coating must be continuous with no exposed uncoated areas.

Extinguishers must display permanent, legible markings including the manufacturer's name or trademark, operating instructions in a prominent position, the label 'Dry Powder Extinguisher', net capacity in kilograms, and gas cartridge capacity. Fire class suitability is indicated by letters 'A', 'B', and 'C' with sizes and colors per IS 2190—for capacities above 2 kg, letters are 2.5 ± 0.5 cm white inside blue squares and circles; for 1-2 kg units, letters are 1.5 ± 0.2 cm inside scaled-down blue shapes. Additional markings include the pressure test declaration indicating the body was tested at 3.0 MN/m², year of manufacture, and pictorial instructions for correct use.

The chemical agents must comply with environmental safety regulations by excluding ozone-depleting substances as per the Montreal Protocol, specifically banning halons and CFCs with high ozone depletion potential. Gas agents employed should have an atmospheric lifetime not exceeding one year to minimize environmental impact. Chemicals used must avoid global warming potential where possible, and coatings should be free from toxic heavy metals such as mercury, lead, cadmium, and hexavalent chromium. These requirements ensure that the fire extinguishers are environmentally responsible and align with international protocols.