The Friction Loss Calculator is also free and easy to use. But, it is requires you to have a device with internet access or downloaded an app.
The Friction Loss Slide Rule starts at ~$20, has a higher probability for human error and the slide rule is the least accurate of the four methods listed.
The Friction Loss Formula is also free to use. But, this method takes the most time, uses somewhat complex mathematics, and has the highest probability of human error.
Fire engine operators must have a basic understanding of friction loss. A lack of understanding can put firefighters at risk with insuficient or excessive nozzle pressure. It may also lead to a broken hose or supply line which has an even greater risk. All fire engine operators should gain a good understanding of friction loss and learn how to calculate pump discharge pressure before operating a fire engine in an emergency situation.