Specifications for the design of outdoor fire hydrants(The Second Part)

Apr 17, 2023 | news

Terms and descriptions related to outdoor fire hydrants

1. post-fire hydrant

  • Connected with the water supply pipeline, it is composed of a valve, water outlet, and plug body, and the valve, water outlet. And part of the shell are exposed to the ground for the fire water supply (or foam mixture) device. Referring to this outdoor fire hydrants specification please.

2. Flush the fire hydrant

  •   A fire water supply (or foam mixture) device that is connected to the water supply pipeline is composed of a valve, a water outlet, and a cock, and is installed underground.

3. crashworthy post-fire hydrant

  • After being hit, only one part breaks, and the bolt body and valve body are not damaged, and it is a kind of above-ground fire hydrant that ensures that the water does not leak.

4. Pressure-reducing-stabilized fire hydrant

  • A fire hydrant can reduce the water inlet pressure within the specified range to a certain water outlet pressure and keep the water outlet pressure automatically stable.

5. folding fire hydrant

  • A kind of fire hydrant that is usually installed below the ground in a folded or retractable form, and can be moved above the ground when in use.

6. fire hydrant coupling

  • A fire water supply appliance that can be quickly connected to an underground fire hydrant and raise the water outlet above the ground.

7. fire hydrant wrench

  • A tool that can control the opening and closing of fire hydrants.

Classification of outdoor fire hydrants

  • Fire hydrants can be divided into ground type, underground type and folding type according to their installation occasions.
  • Fire hydrants can be divided into flange type and socket type according to the connection form of the water inlet.
  • Fire hydrants are divided into common type and special type according to their uses, and special types are divided into foam type, anti-collision type, pressure regulating type, pressure reducing and stabilizing type, etc.
  • According to the nominal diameter of the water inlet, the fire hydrant can be divided into two types: 100mm and 150mm.
  • The nominal pressure of the fire hydrant can be divided into two types: 1.0MPa and 1.6MPa, among which the socket type fire hydrant is 1.0MPa, and the flange type fire hydrant is 1.6MPa.

Technical requirements for outdoor fire hydrants

structure

The structural design of the fire hydrant should ensure that the minimum internal flow area of the fire hydrant is not less than 85% of the nominal diameter area when the fire hydrant is in use.

Material

  • The plug body, valve body, flanged pipe, and elbow of the fire hydrant should be made of gray cast iron HT200 or other metal materials with mechanical properties not lower than HT200 that meet the requirements of GB/T 9439. The bolt body of the anti-collision fire hydrant shall be made of gray cast iron HT250 or other metal materials whose mechanical properties are not lower than HT250 by GB/T 9439.
  • The valve seat and valve stem nut of the fire hydrant shall be made of cast copper alloy ZCuZn38 or other metal materials whose mechanical properties are not lower than ZCuZn38 by GB/T 1176.
  • The valve stem of the fire hydrant should be made of low-carbon steel, and the surface should be chrome-plated or other surface treatment methods with performance not inferior to chrome-plating should be adopted.
  • The hose connection port and the suction pipe connection port of the fire hydrant should use lead brass or stainless steel with mechanical properties not lower than HPb59.
  • The conduit and connecting pin of the valve stem of the foam fire hydrant shall be made of stainless steel.

Appearance Quality

1. The surface of the iron casting of the fire hydrant should be smooth, and the upper exposed part should be painted with red paint after the anti-rust paint is applied. The color should be smooth and uniform without cracks, scratches, and bruises; Other preservative treatments.

2. The surface of the copper casting of the fire hydrant should have no obvious defects such as blisters, pores, and cracks.

opening height

Except for pressure-regulating fire hydrants, the opening height of fire hydrants with a nominal water inlet diameter of 100mm should be greater than 50mm, and the opening height of fire hydrants with a water inlet nominal diameter of 150mm should be greater than 55mm.

Inlet connection size

  • The flange connection size of the flange fire hydrant should meet the requirements of the following figure and Table 1
Table 1 Flange Connection Dimensions of Flange Fire Hydrant Unit (mm)
Inlet nominal diameterFlange outer diameter DBolt hole center circle diameter D1Bolt hole diameter d0Number of bolts/piece
Basic Sizelimit DeviationBasic Sizelimit DeviationBasic Sizelimit Deviation
100220±2.8180±0.517.5±0.438
150285±3.1240±0.822±0.52
  • The socket connection size of the socket fire hydrant shall meet the requirements of the figure below and Table 2 and Table 3
Table 2 Socket Connection Dimensions of Socket Type Fire Hydrant Unit (mm)
Inlet nominal diameterSize of each part
abce
100-1501510206
Table 3 Socket Size of Socket Type Fire Hydrant Unit (mm)
Inlet nominal diameterInner diameter of socketABCEPlδχR
1001383626121090951332
15018936261210951051332

Sealing performance

When the fire hydrant is at the nominal pressure, there must be no leakage at each connection part and the residual water discharge device.

Water pressure

When the fire hydrant is at 1.5 times the nominal pressure, all castings must not have leakage or damage that affects normal use.

Drainage device

The fire hydrant shall be as equipped with an automatic residual water discharge device, which shall not leak when the fire hydrant is in normal use (fully open) and the water pressure is not less than 0.1MPa.

Regulating performance

The pressure-regulating fire hydrant should have pressure-regulating performance. When the water inlet pressure of the fire hydrant is 1.2MPa, the water outlet pressure should be adjustable between 0.3MPa and 1.0MPa.