What is the required spacing between external hydrants for an industrial plant?

For an Ordinary or High Hazard plant, the spacing is 30 metres. For a Light Hazard, it is 45 metres (Clause 4.2.1).

What is the minimum running pressure required at the furthest hydrant?

The pressure at the highest or most remote hydrant shall not be less than 3.5 kg/cm² or 350 kPa (Clause 5.3.3).

What is the minimum water storage capacity required for an Ordinary Hazard property?

The water supply should have a flow rate of 2850 litres/minute for a duration of 120 minutes, totaling 3,42,000 litres of minimum storage (Table 2).

What is the minimum pipe size for the hydrant ring main?

The diameter of the external hydrant mains shall not be less than 150 mm (Clause 6.1.1).

IS 13039

: 1991

External hydrant systems - provision and maintenance - Code of practice

CurrentFrequently UsedCode of PracticeBIMFire Safety · Fire Fighting

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This code of practice provides guidelines for the design, provision, installation, and maintenance of external fire hydrant systems. It covers hazard classification, water supply capacity, pump requirements, pipeline network design, and the placement of hydrants to ensure effective initial-stage firefighting for external risks at buildings and industrial sites.

External hydrant systems - provision and maintenance - Code of practice

Quick Reference Values

Minimum pressure at most remote hydrant3.5 kg/cm² (350 kPa)

Maximum hydrant spacing for Ordinary/High Hazard30 m

Maximum hydrant spacing for Light Hazard45 m

Minimum hydrant main pipe diameter150 mm

Minimum water supply duration for Ordinary Hazard120 minutes

Minimum water supply duration for High Hazard180 minutes

Distance of hydrant from buildingMinimum 2m and Maximum 15m

Practical Notes

Always use this code in conjunction with the National Building Code (NBC) of India, Part 4, as the NBC often provides more comprehensive or updated requirements.

The classification of hazard (Light, Ordinary, High) as per Table 1 is the most critical first step as it dictates all subsequent design parameters like water capacity, pressure, and hydrant spacing.

Pay close attention to the pump configuration (Jockey, Main, Standby) and ensure a reliable alternate power source (like a diesel engine for the main or standby pump) is provided for system reliability.