Functional requirements for 2000 kg dry powder tender for fire brigade use
1984 Edition

The fire tender must have a gross vehicle weight of at least 8,500 kg including crew and equipment, achieve a maximum speed of 72 km/h when fully loaded, accelerate from 0 to 63 km/h within 55 seconds, and be capable of starting on a 1 in 4 gradient. Braking must enable stopping from 48 km/h within 15 meters on dry surfaces, with a handbrake able to hold the vehicle on the same gradient in neutral. Dimensional limits include a maximum wheelbase of 4,500 mm, turning circle up to 20 meters, ground clearance not less than 230 mm, and an overall width not exceeding 2,500 mm. The tender uses foam-compatible dry chemical powder propelled by nitrogen, equipped with hose reels and a long-range monitor, and requires flushing after use to ensure operational readiness.

Metal components exposed to the atmosphere or in contact with the dry powder must be manufactured from corrosion-resistant metals such as stainless or galvanized steel or be treated with protective coatings like painting or powder coating. Valves, nozzles, pipes, fittings, and pressure gauges must use approved non-reactive materials compatible with dry powder. Internal surfaces of powder vessels must be coated either with a lead-tin alloy containing at least 10% tin and a minimum thickness of 0.12 mm or with epoxy paint to prevent corrosion and contamination.

The system comprises vessels holding a total of 2,000 kg dry powder, either in a single container or two separate vessels of 1,000 kg each, each equipped with individual filling, drainage, safety valves, pressure gauges, isolation, and discharge valves. Nitrogen gas acts as the expellant, supplied separately to each vessel with pressure regulation. Powder is discharged through two hose reels fitted with trigger-operated pistol grip nozzles and/or a long-range monitor mounted atop the vehicle, which has adjustable discharge rates of 15, 25, and 40 kg/s and allows 360° horizontal and 100° vertical movement. Controls for powder discharge are located on an illuminated, well-marked control panel accessible to the operator, with levers placed ergonomically for rapid operation.

The tender must carry fireman's axes (two units conforming to IS 926-1970), a large axe, a hand axe (both per IS 5505-1969), a shovel (as per IS 274 Parts 1 & 2), and four spare nitrogen gas cylinders of 50 liters each. Additional mandatory accessories include an electrically operated siren with a 1 km range controlled from the driver’s cab, two fog lamps, a reversing light, two airfield obstruction marking lights (front and rear), a roof-mounted blue revolving beacon with 360° coverage, a searchlight with tripod and a cable not exceeding 30 meters with minimal voltage drop, a spot light positioned near the rear of the driver’s cab, an inspection lamp with a plug socket on the control panel, and tools necessary for routine maintenance beyond the standard chassis kit.

Under fully equipped and loaded conditions, excluding crew weight, the fire tender must maintain stability and not overturn when the surface tilts up to 25° from the horizontal in either direction. This requires a low center of gravity and appropriate base width to ensure the line of action of the vehicle’s weight remains within its support area. The gross vehicle mass must be at least 8,500 kg, with dimensional restrictions on wheelbase (maximum 4,500 mm), turning circle (up to 20 m), ground clearance (minimum 230 mm), and overall width (maximum 2,500 mm). These parameters collectively ensure the appliance remains safe and operationally secure on slopes and uneven terrain.