# Calculating Friction Loss, Nozzle Reaction, and Nozzle Flow Using the Hose and Nozzle Easy Chart

© 2008 by Ed Kotski

All Rights Reserved

Download Hose and Nozzle Easy Chart as PDF, with Instructions

If you can draw a straight line, you can calculate friction loss, nozzle flow, and nozzle reaction forces in fire service hoselines. The chart, technically called a nomograph, acts as a vernier scale to quickly connect known information to find friction loss, nozzle reaction forces, and nozzle flow on the fire ground. To start, download and print the PDF Document.

## Calculating Friction Loss

To calculate hose friction loss per 100 ft of hose:

- Locate the hose diameter on the Hose Diameter Scale
- Locate the flow rate on the Flow Rate Scale
- Connect these two points
- Find the point where the line you drew crosses the Hose Friction Loss Scale. This is the friction loss in psi per 100 ft hose.

## Calculating Nozzle Flow and Reaction Forces

### Combination Nozzle Calculations

- Locate the operating pressure of the nozzle on the Nozzle Pressure Scale. For Combination Nozzles, this is typically 100 psi.
- Locate the flow rate on the Flow Rate Scale.
- Connect these two locations with a straight line
- Locate the Nozzle Reaction Force where the line you drew crosses the Reaction Scale

### Smooth Bore Nozzle Calculations

- Locate the nozzle diameter on the Nozzle Diameter Scale
- Locate the nozzle operating pressure on the Nozzle Pressure Scale
- Connect these two locations with a straight line
- Locate the flow rate where the line you drew crosses the Flow Rate Scale

## Combining Friction Loss, Nozzle Flow, and Nozzle Reaction Forces

Combining all calculations on a single chart is done in two steps

- Using the Nozzle Scales, connect the operating pressure and the nozzle diameter (smoothbore) or flow rate (combination nozzle)
- Read the Reaction Force where this line crosses the Reaction Force Scale and the Flow Rate from the Flow Rate Scale. DO NOT read the friction loss from this line.
- Connect the hose diameter to the flow rate and read the friction loss per 100 ft of hose where the new line crosses the Hose Friction Loss Scale

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