How do you calculate the flow of a hydrant?
In other words, if your pitot pressure is 28 psi and your orifice size is 4, your theoretical discharge according to the table is 2,526 GPM. If the coefficient of your hydrant outlet is 0.9, multiplying 2,526 x 0.9 finds the actual rate of flow: 2,273.4 GPM.
What is the flow rate of a fire hydrant?
| CLASS | Hydrants that on individual test usually have a flow capacity of: |
|---|---|
| CLASS AA | 1,500 gpm or greater |
| CLASS A | 1,000 gpm or greater |
| CLASS B | 500 to 1,000 gpm |
| CLASS C | <500 gpm |
How do I calculate GPM?
The formula to find GPM is 60 divided by the seconds it takes to fill a one-gallon container (60 / seconds = GPM). Example: The one-gallon container fills in 5 seconds, breakdown: 60 divided by 5 equals 12 gallons per minute.
What do colors of fire hydrants mean?
The colors indicate the rated water-flow capacity of that particular hydrant: Red indicates water-flow capacity of less than 500 gallons-per-minute (GPM). Orange indicates water-flow capacity of 500 to 999 GPM. Blue indicates water-flow capacity of 1,500 or greater GPM.
What is the NFPA Standard for hydrants?
NFPA 291 provides guidance on fire flow tests and marking of hydrants in order to determine and indicate the relative available fire service water supply from hydrants and to identify possible deficiencies which could be corrected to ensure adequate fire flows as needed.
What is the required clearance around a fire hydrant?
3 ft
A 3 ft (914.4 mm) clear space shall be maintained around the circumference of fire hydrants except as otherwise required or approved. Hydrants – Clearances of seven and one half feet (7’6”) in front of and to the sides of the fire hydrant, with a four feet (4′) clearance to the rear of the hydrant.
What is normal flow rate?
Normal flow rate is 1 atmosphere (101.3 kPa) or 14.696 psia at 32 0F (0 0C). Actual flow rate is the actual volume of fluid that passes a given point based on given pressure and temperature of the process.