Six checks a plant engineer or a buyer can use before the RFQ. Each one follows the method already on the engineering tools. It is not a stamped design.
IS 15105 · NBC 2016 Part 4
Sprinkler selection by hazard
Start from the occupancy, not from a favourite head. IS 15105 groups the risk as light, ordinary or high hazard. Light hazard (offices, hospitals, schools) typically uses a lighter design density and a smaller remote area than ordinary hazard (manufacturing, parking, retail). High hazard, including storage, needs the higher density and the matching orifice. The temperature rating follows the ceiling temperature: ordinary 68 °C or 79 °C unless the roof or a process is hotter. Keep the sprinkler type (pendent, upright, sidewall) matched to the ceiling and the obstruction. Heads and the 25 NB branch are counted per floor. The pump and the tank stay on the remote design area, not on the whole building area.
Size the fire systemSprinklers in the catalogue
IS 13039 · NFPA 20
Pump sizing basics
A fire pump is a duty, not a model name. Flow comes from the hydrant table or the sprinkler remote area. Head is residual pressure at the most remote outlet, plus static lift, plus pipe friction. IS 13039 sets a floor from the number of hydrants and the hazard: the desk uses 96 m³/h at 5.6 kg/cm², 171 m³/h at 7 kg/cm², and 410 m³/h at 8.8 kg/cm² as those floors. The jockey only makes up leakage. It must meet the duty flow and a head from the duty up to 15% above it. A pump that is far above the duty head is not a match. Where the catalogue has no fitting pump, the line stays price on request.
Fire pump requirementPumps in the catalogue
IS 732 · IS 3961
Cable sizing and voltage drop
Size the cable twice and take the larger result. First, current: for three phase, I = kW × 1,000 / (√3 × volts × power factor). Power factor on this desk must sit between 0.5 and 1. Second, voltage drop along the actual run, default limit 5%. A cable that carries the amps but drops too much voltage is still too small. The desk prefers one aluminium XLPE armoured size — a single core count, not a kit of several sizes, and not an unarmoured cable offered as armoured. Confirm the laying condition and the ambient temperature before the purchase order.
Cable calculatorElectrical catalogue
IS 1239 · IS 3589 · IS 4985
Pipe material: MS, GI, CPVC, HDPE
Match the pipe to the fluid and the code, not to the last purchase. Mild steel (MS, often ERW) is the usual underground and yard fire-water main when the specification calls for it, with a wall thickness that is part of the line. Galvanised iron (GI) is the common above-ground hydrant and sprinkler pipe to IS 1239; do not substitute stainless or plain carbon for a GI line, or the reverse. CPVC is a light-hazard wet sprinkler option where the approval and the temperature allow it. HDPE (IS 4985) is for buried raw or fire water where a fused joint is specified. A 50 NB, 2 inch and DN50 line are the same size. Write the NB and the standard on the RFQ.
Pipe head lossPipes, valves and fittings
IS 14846 · IS 5290 · IS 5312
Valve type selection
Use the valve that the duty actually needs. A gate valve isolates a line; it is a poor throttle. A butterfly valve isolates and is the usual compact choice on a fire header. A non-return valve stops reverse flow at a pump discharge. A hydrant landing valve (oblique, often 63 mm) is the outlet, not a substitute for the yard isolation valve. A pressure-reducing or pressure-relief valve is a control device and needs the set pressure written down. Class 150 is a flange rating. It is not the same as 150 NB. Name the size, the ends and the rating on the line.
Valves in the cataloguePiping requirement
IS 13039
Fire water tank sizing
Tank volume follows the pump that must run for the code duration. Volume in cubic metres is flow in litres per minute, times hours, times 60, divided by 1,000. A 6,825 L/min pump for 3 hours is about 1,229 m³. Duration depends on the hazard, not on a favourite tank size. Above 100 kL the desk prices a zincalume tank per kL on the nearest published band at or above the volume. A heavy steel bolted tank is a different product and is not used for that zincalume band. A tank above 1,000 kL is price on request. A tank of 100 kL or less stays a lump-sum listing.
Tank calculatorFire protection catalogue
Standards cited by number for reference; verify designs with a qualified engineer.
