Conduct the test
- Record static pressure reading from gauge cap.
- Slowly open hydrant using the gate valve to purge air from the hydrant. When hydrant is full of water, open gate valve to desired flow-rate (usually full open).
- When the flow-rate stabilizes,
- Record nozzle pressure from the remote reader.
What does a hydrant flow test tell you?
Hydrant flow tests are conducted to measure real world pressure and flow in the water system. Hydrant flow tests are required for fire sprinkler design and for water modeling purposes. They are generally known as fire flow tests as the highest demands on the system occur when fighting a fire.
What is the average flow rate of a fire hydrant?
Typical flow rate for fire hydrant discharge outlets are as follows5: 2½-inch discharge outlet: 10 psi – 500 gpm. 15 psi – 610 gpm.
What is a pitot reading?
The pitot gauge measures the nozzle pressure of a fire stream, which is than referenced on a chart for the correct gpm. It has a blade with a very small hole on the end that is inserted into the fire stream and sends the pressure to the gauge to come up with a reading.
What does a pitot gauge measure?
A pitot (/ˈpiːtoʊ/ PEE-toh) tube, also known as pitot probe, is a flow measurement device used to measure fluid flow velocity. It is widely used to determine the airspeed of an aircraft, water speed of a boat, and to measure liquid, air and gas flow velocities in certain industrial applications.
What is fire flow rate?
Fire Flow is formally defined as the “flow rate of a water supply, measured at 20 psi (138 kPa), that is available for fire fighting.” ( IFC 200-2018 Appendix B Section B102) Fire flow is used to determine the quality of a water supply to an area.
What is the maximum flow rate for 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 |
What NFPA 291?
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.
How many GPM can a fire hydrant flow?
Do pitot gauges really measure fire hydrants?
In theory, pitot gauges make it simple to measure the flow of fire hydrants and convert readings in pounds per square inch (PSI) to gallons per minute (GPM), enabling inspectors to quickly uncover reduced flow rates.
What is a pitot gauge and how does it work?
The captured PSI readings can be used to calculate the disparities in pressure between two points along a distribution system. Each pitot gauge features a blade, a handle, and a pressure gauge. The desirable unit of measure we seek from hydrant flow testing is a hydrant’s GPM.
How do I get a pitot pressure reading?
Utilizing hand held pitot gauges, diffusers, and The Hose Monster Company™ equipment are methods that allow you to obtain the pitot pressure reading. FTS allows you to input up to 9 different pitot readings with associated coefficients of discharge per flow test, and it calculates the GPM automatically.
What should I look for in a pitot test kit?
Look for a rotating pitot gauge on a quick disconnect fitting for easier reading and faster draining of the system. For playpipe or hose nozzle readings, choose a kit with a notched blade in addition to the straight blade required for hydrant and pump testing.
