Fire and Water Flow

What’s the best size for an “attack line?” What factors are the highest priority on your department? Maximum flow Maximum mobility Speed-How fast and how much Ease of deployment and pickup Personnel available Water supply available

Larger Attack Hose Lines Equal Higher initial attack flow capability Less friction loss Longer hose lay capability Using more of pumps capacity

Higher Flows Equal Quicker fire knockdown Personnel spend less time in “combat” More lives saved More property saved

Friction Loss  “Rule of Thumb” Hydraulics 1 3/4" Hose - 30 lbs. friction loss per 100 ft. 2 1/2" Hose - 10 lbs. friction loss per 100 ft. Optimal Fog Nozzle pressure is 100 PSI Optimal Solid bore Nozzle pressure is 60 PSI

Nozzle Basics	Discharge
Smooth Bore Nozzle - Handline	50 PSI
Smooth Bore Nozzle - Master Stream	80 PSI
Combination Nozzle - (all types)	100 PSI

National Fire Academy Formula for Quick Size-up
GPM = L x W / 3                    L = Length       W = Width
Fire knockdown in 30 seconds or less
Multiply GPM by number of floors involved
Can be adjusted for actual % of involvement
Choose appropriate size & number of attack lines based on GPM required & other situational factors

Iowa State University Formula
GPM = L x W x H / 100                    L = Length       W = Width      H = Height
Fire knockdown in 60 seconds or less
Normally for enclosed areas
Can be used in pre-planning water requirements for a building or room