Friction Loss Worksheet

Use this worksheet to calculate the total friction loss in your irrigation system's pipe sections. Enter the details for each pipe section to determine pressure loss and ensure adequate pressure at the last head.

Friction Loss Worksheet

Carry over selections (Type, Size, GPM) when adding new section

Auto-Calculate PSI Loss

Section	Type	Size	GPM/Flow	Length	PSI Loss / 100	PSI Loss this item

		Total PSI Loss in Pipes:

Estimated pressure loss in fittings (10%)

Calculation Reference

These are calculations you must learn and memorize for accurate friction loss estimation. You will be doing these calculations frequently on your Exam.

1. Section PSI Loss

Formula: Length ÷ 100 × Chart_Value

Calculator Tip: Convert feet to decimal factor first. For 150', enter 150 ÷ 100 = 1.5. Then multiply 1.5 × Loss/100.

2. Fitting Loss (10%)

Formula: Total_Pipe_Loss × 0.10

Calculator Tip: Sum all your individual pipe section losses (the result in the table footer). Leave that number on your screen and hit × .1 to find fitting loss.

3. Remaining Pressure

Formula: Start_PSI - Pipe_Loss - Fit_Loss

Total PSI loss in pipe from the valve to the last head:
Pressure at the valve discharge:
Estimated pressure loss in fittings (10% of pipe loss):
Pressure loss in pipe from valve to last head:
Pressure remaining at the last head: