ℹ️ About This Calculator
The gas appliance sizing calculator aggregates the input ratings of all gas-burning appliances in a building to determine the total connected gas demand. Applying a diversity factor gives the design gas demand, which governs the selection of the gas meter, service regulator, and service pipe size. Per IS 6044 and IS 9062 (gas appliance installation).
IS 9062 covers gas appliance installation requirements. Every gas appliance must be approved by BIS and have the ISI mark. Commercial kitchen appliances are governed by IS 6315. Gas meter sizes (G-rating): G4 = 6 m³/hr; G6 = 10 m³/hr; G10 = 16 m³/hr. Meters are provided by the city gas distribution company. Service regulators maintain downstream pressure at 21 mbar (domestic) regardless of supply pressure variations.
❓ Frequently Asked Questions
What gas input rating should I use for kitchen appliances?
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Typical input ratings: domestic burner (2-burner hob) = 1.5–2.5 kW per burner; hot plate (commercial) = 3–5 kW per burner; gas oven = 5–10 kW; tandoor = 10–15 kW; commercial water heater = 10–24 kW; boiler = 30–500 kW. Use actual appliance nameplate ratings when available. Add 10% margin for unaccounted small appliances.
How is the gas meter size selected?
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Gas meters are rated by their maximum throughput: G4 handles up to 6 m³/hr; G6 up to 10 m³/hr; G10 up to 16 m³/hr; G16 up to 25 m³/hr; G25 up to 40 m³/hr. Select the meter where your design demand falls in the middle third of the meter capacity for accurate measurement (meters are less accurate at very low flows). The city gas company selects and installs the meter.
Is a gas regulator required at every appliance?
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At the building entry: a service regulator reduces supply pressure to 21 mbar (domestic) or higher (commercial). Individual appliances with integral pressure regulators (most modern appliances) do not need additional regulators. Appliances without regulators (some industrial equipment) need an appliance regulator set to the required operating pressure. All flexible connections must be gas-grade hose, not general-purpose rubber.
What happens if I connect more appliances than the gas pipe/meter can supply?
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If the gas pipe is undersized: pressure drops below the minimum at appliances. Effect: yellow/orange flames (incomplete combustion), carbon monoxide production, sooting, poor performance. If the meter is undersized: the meter rotates faster than designed, inaccurate billing, potential meter damage. Always size the service pipe and meter for the maximum expected simultaneous demand.
Do I need special ventilation for gas appliances?
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Yes, per IS 9062: open-flued appliances (type B) need combustion air supply (minimum 2 cm² free area per kW of appliance rating) and a flue vent to the outside. Room-sealed appliances (type C) draw air and discharge flue gases directly through the external wall – no room ventilation required. All gas appliances in enclosed kitchens must have CO detectors per BIS 2016 amendment. LPG appliances need low-level ventilation; PNG appliances need high-level vents.
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