Understanding Fire Hydrant Ring Mains: Loop Design and Pressure Relief Valves in Sanand Factories

Designing proper safety profiles is essential for any industrial or corporate facility. For businesses operating in Gujarat, fire safety is both a legal necessity and a critical investment to protect employees, assets, and business continuity. Under the National Building Code (NBC 2016 Part 4) and the Gujarat Fire Prevention Act, facility occupiers must install certified safety systems and secure valid Fire NOC approvals. This guide explores the engineering standards, installation rules, and compliance requirements in detail.

The Engineering Case for Closed-Loop Hydrant Layouts

Sanand GIDC contains modern engineering, automotive, and manufacturing plants with large plot areas. Standard single-line dead-end water mains suffer from high frictional pressure drops at remote outlets. A closed-loop ring main piping network runs around the perimeter of the factory buildings, distributing water flow and maintaining pressure throughout the system.

1. Loop Sizing and Friction Loss Calculations

The ring main diameter is calculated using the Hazen-Williams formula to ensure pressure drops do not fall below the required 3.5 bar at the most remote hydrant outlet during full discharge. Heavy-duty carbon steel pipes (complying with IS 1239 or IS 3589) are wrapped with anti-corrosive tapes before burial to protect the pipes from acidic soil conditions.

2. Pressure Relief Valves (PRVs) and Water Hammer Protection

When a main electric fire pump starts, it reaches full pressure within seconds, sending a high-pressure wave (water hammer) through the loop. To prevent pipe joint failures, a fast-acting pressure relief valve is installed on the pump discharge header. When pressure exceeds the set limit, the valve opens, redirecting excess water back to the storage tank.

3. Isolation Valve Configurations and Maintenance

Under IS 13039, loop isolation valves (typically gate or butterfly valves) must be installed at intervals along the ring main. This allows maintenance teams to isolate a single section of pipe for repairs while keeping the rest of the loop pressurized. JSNM Engineers provides certified industrial ring main installations and pressure testing in Gujarat.

Frequently Asked Questions