Reference Table

Friction Loss Table

Build a printable quick-reference table for common fire hose sizes. Values use FL per 100 ft = C × (GPM/100)², then multiply by selected hose length.

Table settings

Hose length shown

Rounding

Hose C values

Hose	C value	Best use
1¾″	15.5	Attack lines
2½″	2.0	Attack / supply
3″	0.8	Supply / leader
4″ LDH	0.2	Supply
5″ LDH	0.08	Supply

Use your department hose test data or SOP values when they differ. Not every listed flow is appropriate for every hose size.

Friction loss values

How to use the table

Pick the hose length closest to the evolution, then find the desired flow. The number shown is estimated friction loss for that hose size and length. Add nozzle pressure, appliance loss, and elevation to estimate pump discharge pressure.

Example: 1¾″ C15.5185 GPM200 ftFL ≈ 105 psiPDP with 50 psi nozzle ≈ 155 psi