Hydrant Valves - Types and Working Process

A fire hydrant refers to an above the ground outlet placed to extend access to a water supply for dousing fires etc. A hydrant system comprises a water supply with sufficient pressure and flow to be delivered through pipes in a building to strategically installed network of valves for fire-fighting. The water supply is usually pressurized in case the hydrants are connected to water mains buried in the street. On the other hand, for hydrants connected to nearby ponds or cisterns these are unpressurized. Upon opening a hydrant valve, the system undergoes a pressure drop that is detected by a pressure switch that activates to start the booster pump(s). This in turn draws the water from the water source to boost the water pressure of the system- thus directing the Water from the hydrant through the layflat fire hose to a nozzle that douses the fire. SKG valves suppliers a comprehensive range of valves for use on hydrants whether fire hydrants or wet rising mains. A range of Hydrant valves are manufactured to suit various requirements that conform to the various ISI standard IS:5290, and satisfying requirements of MMD. Each SKG valve undergoes stringent Quality Controls to fulfil or exceed the required specifications. Apart from undergoing spectrographic raw material analysis the critical moisture content of the molding sand is also thoroughly checked. The high-quality materials used not only enables us to be fully BSS041 (1987) compliant but imparts the ability to use with fresh, brackish or seawater. Access and successful use in high temperature fire zones. Is ensured by a dual seat design.

WORKING PROCESS

Every hydrant typically has one or more outlets placed conveniently for connecting a fire hose. In case the water supply is pressurized, the hydrant also has a built in one or more valves for regulating the water flow. Sufficient waterflow for firefighting, is ensured by enabling hydrant size sufficient to provide a minimum flow rate of about 945 liters per minute or 15.75litres/sec, although most hydrants have a capacity to provide more. The Fire Hydrant valves and Landing valves are designed to be robust, not freeze in harsh environments, and operate in a fire and conforms to stringent specifications. Some incorporate a reducing valve to regulate the outlet pressure with a varying inlet pressure required in some situations.

TYPES OF HYDRANTS

Basically, there are two kinds of pressurized fire hydrants: a) wet-barrel and b) dry-barrel. In a wet-barrel design, as the hydrant connects directly to the pressurized water source, the upper section, known as the barrel, stays always filled with water. In a dry-barrel design of hydrant (used where temperatures fall below (0° C), the hydrant itself is separated from pressurized water source by a main valve incorporated in the lower section of the hydrant below the ground level.

Although the basic components of all fire hydrants many types exist:

Oblique type Landing Valve-Stainless Steel

ISI 5290 Type A marked hose and Sizes are available in i) (38mm), ii) (63mm), & iii) Inlet is Flanged or BSPT/NPT threaded, and outlet Female or male BSPT/NPT threaded.

Double Outlet Type Landing Valve – Stainless Steel

IS 5290 Type B marked hose made of Gun Metal 4” NB Flanged inlet ANSI as well as PN16 specs- hand wheel Grey cast Iron; inlet -Flanged or BSP/NPT threaded, and outlet is Female or male BSPT/NPT

Oblique type Landing Valve – Gunmetal

IS 5290 Type A hose in three sizes i) (38mm), ii) (63mm), and iii)76.2mm. hand wheel Grey cast Iron; inlet -Flanged or BSP/NPT threaded, and outlet is Female or male BSPT/NPT