Specification for portable fire extinguisher mechanical foam type
2001 Edition

The extinguisher body is required to be fabricated from stainless steel conforming to IS 6911 or mild steel sheets as per IS 513, ensuring adequate thickness calculated based on design pressure. Internal surfaces must have a plastic or rubber lining with a minimum thickness of 0.5 mm applied by centrifuge and heat curing, tested for adhesion at 15 kg/cm² for 120 ± 8 hours at 27 ± 5°C. Other parts such as neck rings, caps, siphon tubes, and discharge fittings use materials like leaded-tin bronze, brass, aluminium alloy, HDPE, and stainless steel, each conforming to their relevant IS codes to ensure durability and compatibility.

Performance testing involves operating the extinguisher at ambient temperature 27 ± 5°C in still air conditions with the foam nozzle held horizontally. The foam jet must project at least 6 meters continuously for a minimum of 25 seconds, discharging 90% of its liquid content within 60 seconds. The foam collected in a leak-proof tray of 1 m² should have a thickness of 50 mm or exhibit an expansion ratio of 6 or higher as per IS 4989 Part 2. Additionally, a fire suppression test using 25 liters of high-speed diesel oil must demonstrate complete extinguishment within 60 seconds of foam discharge.

The standard prohibits the use of ozone-depleting substances (ODS) listed under the Montreal Protocol in fire extinguishers. Coatings on metallic surfaces must not contain mercury, lead, cadmium, chromium VI, or their oxides beyond trace natural impurities (up to 0.1% by weight). Internal linings are required to be plastic or rubber with proven chemical resistance and adhesion properties. CO2 extinguishers are permitted on a temporary basis until environmentally safer alternatives are available. The optional ECO-Mark certification encourages environmentally friendly products that meet the combined ISI and ecological standards.

Extinguishers must be clearly labeled with operating instructions in prominent lettering, the phrase 'MECHANICAL FOAM,' nominal liquid charge in liters, CO2 cartridge capacity, manufacturer’s name or trademark, and the liquid fill level. A caution advising that 'after discharge the extinguisher must be carefully washed out with fresh water using at least two changes' must also be displayed. For Class B fire suitability, a black letter 'B' of 2.5 cm height is to be placed inside a 4 cm cream-colored square (shade IS 5:355). Paint and marking materials must comply with IS 5 and IS 2932 standards.

IS 10204 mandates application of an internal plastic or rubber lining at least 0.5 mm thick, applied by centrifuging and heat curing, with adhesion tested by exposure to 15 kg/cm² pressure for 120 ± 8 hours at controlled temperature. Materials for components are selected for corrosion resistance including stainless steel, leaded-tin bronze, brass, and acid/alkali resistant rubber. Durability is verified through mechanical tests such as 100 screw/unscrew cycles on threads and hydraulic pressure testing at 45 kgf/cm² combined with thermal cycling between 5°C and 60°C with no leakage or deterioration permitted.

The extinguisher cylinder is typically made from seamless or alloy steel with adequate tensile strength and ductility. Wall thickness is designed to withstand operating pressures safely. Cylinders are cylindrical with convex ends to uniformly distribute stress. Welding is performed using arc welding (TIG/MIG) or electric resistance methods, with welds inspected for defects such as cracks or porosity using radiographic or ultrasonic testing. Proper edge preparation ensures full penetration in butt joints. Post-welding heat treatments may be applied to relieve residual stresses. Compliance with hydrostatic test pressures and applicable IS welding codes such as IS 1323, IS 819, IS 1261, and IS 9595 is mandatory.

Sampling is conducted randomly from production lots defined by consistent type, design, and manufacturing conditions. The sample size and acceptance criteria are specified in Annex C, based on lot size and acceptable quality levels. Testing includes mechanical endurance through repeated screwing of caps, hydraulic pressure testing at 45 kgf/cm², and environmental cycling involving temperature extremes and humidity exposure. A lot is accepted only if all sampled units meet performance and physical criteria, ensuring reliability given the critical safety function of extinguishers.