# California Pipe Flow Metering Method

With the California Pipe Flow Metering Method the discharge from the open end of partially filled horizontal pipes discharging freely into the air can be measured.

The discharge can be calculated as

*q = 8.69 (1 - a / d) ^{1.88} d^{2.48} (1) *

*where *

*q = discharge (ft ^{3}/s)*

*a = distance in the plane end of the pipe - from the top of the inside surface of the pipe - to the water surface (ft)*

*d = internal diameter of pipe (ft)*

The equation is empirical and can be used for pipes in the diameter range* 3 - 10 in*.

*1 mm = 0.00328 feet**1 ft = 0.3048 m = 12 in = 0.3333 yd = 30.48 cm = 304.8 mm**1 ft*^{3}/s = 0.0283168 m^{3}/s = 101.9 m^{3}/h = 28.32 dm^{3}(litre)/s = 60 ft^{3}/min = 373.7 Imp.gal (UK)/min = 448.9 gal (US)/min (US gpm)

### California Pipe Flow Example

In the discharge on a horizontal *4 inches* PVC sewer pipe the distance from the top inside pipe to the water flow is *3 inches (0.25 ft)*. The inside diameter of the PVC pipe is *4.069 in (0.34 ft)*.

The discharge can be calculated as

*q = 8.69 (1 - (0.25 ft) / (0.34 ft)) ^{1.88} (0.34 ft)^{2.48} *

* = 0.049 ft ^{3}/s*

### California Pipe Flow Calculator - Imperial Units

### California Pipe Flow Calculator - Metric Units

## Related Topics

### • Flow Measurements

Flow metering principles - Orifice, Venturi, Flow Nozzles, Pitot Tubes, Target, Variable Area, Positive Displacement, Turbine, Vortex, Electromagnetic, Ultrasonic Doppler, Ultrasonic Time-of-travel, Mass Coriolis, Mass Thermal, Weir V-notch, Flume Parshall and Sluice Gate flow meters and more.

### • Sanitary Drainage Systems

The purpose of the sanitary drainage system is to remove effluent discharged from plumbing fixtures and other equipment.

## Related Documents

### Comparing Flowmeters

A limited comparison of flowmeter principles - regarding service, rangeability, pressure loss, typical accuracy, upstream pipe diameters, viscosity and relative costs.

### Flow Section Channels - Geometric Relationships

Geometric relationships like area, wetted perimeter and hydraulic diameter.

### Flowmeter - Accuracy

Introduction to accuracy in flow measurement devices.

### Flowmeters - Turndown Ratios

Turndown ratio (Rangeability) can be used to compare flow measurement devices like orifices, venturi meters etc.

### Fluid Flowmeters - Comparing Types

An introduction to the different types of fluid flowmeters - Orifices, Venturies, Nozzles, Rotameters, Pitot Tubes, Calorimetrics, Turbine, Vortex, Electromagnetic, Doppler, Ultrasonic, Thermal, Coriolis.

### Manning's Formula and Gravity Flow

Calculate cross-sectional average velocity flow in open channels.

### Open Channel Weirs - Volume Flow Measurements

Weirs can be used to measure flow rates in open channels and rivers - common for water supply and sewage plants.

### Orifice, Nozzle and Venturi Flow Rate Meters

The orifice, nozzle and venturi flow rate meters makes the use of the Bernoulli Equation to calculate fluid flow rate using pressure difference through obstructions in the flow.

### Pitot Tubes

Pitot tubes can be used to measure fluid flow velocities by measuring the difference between static and dynamic pressure in the flow.

### Sewer Pipes - Capacities vs. Slope

Carrying capacities of sewer and wastewater pipes - *gpm and liter per second*.

### Sluice Gate - Volume Flow Measurements

Sluice gates can be used to control and measure volume flow rates in open channels and rivers, mainly in connection to hydro power plants.

### Ultrasonic Doppler and Time of Flight Velocity and Volume Flow Meters

An basic introduction to the ultrasonic Doppler and Time of Flight Flow Meters.

### Volume Flow - Online Unit Converter

Convert between volume flow units like *gpm, liter/sec, cfm, m ^{3}/h*.

### Vortex Flowmeters - Shedding Frequency vs. Volume Flow Rate

The vortex shedding frequency created around a bluff body and flow rate.

### Water - Volume Flow Measurement

A manual providing guidance in selecting, managing, inspecting, and maintaining water measurement devices - describes standard methods and devices commonly used to measure irrigation water.