Fixed & Selectable Flow Nozzles

Combination (Fog) Nozzle Development

Fixed (Single) Flow Nozzles...  Fixed gallonage nozzle has one hole size  Smooth Bore Nozzle  Single Flow Combination (Fog) Nozzle  One correct nozzle pressure » To achieve rated flow » To achieve optimum performance  Pump pressure must be changed each time nozzle or tip is changed  Fixed gallonage nozzle has one hole size  Smooth Bore Nozzle  Single Flow Combination (Fog) Nozzle  One correct nozzle pressure » To achieve rated flow » To achieve optimum performance  Pump pressure must be changed each time nozzle or tip is changed

Selectable Flow Nozzles...  Selectable gallonage nozzle has a few different hole sizes  Manually changed  One correct nozzle pressure » To achieve rated flow » To achieve optimum performance  Pump pressure must be changed each time setting is changed  Selectable gallonage nozzle has a few different hole sizes  Manually changed  One correct nozzle pressure » To achieve rated flow » To achieve optimum performance  Pump pressure must be changed each time setting is changed

In relation to flow, a stacked tip smooth bore & a selectable gallonage nozzle are the same... A combination of 3 or 4 fixed hole sizes

Flow of Different Size Orifices

Advantages of Fixed & Selectable Flow Nozzles...  Simple and familiar design  Easily serviced with commonly available parts  Economical to purchase  When pumped at correct pressure, will provide rated flow  Simple and familiar design  Easily serviced with commonly available parts  Economical to purchase  When pumped at correct pressure, will provide rated flow

Limitations of Fixed & Selectable Flow Nozzles...  Changing size always requires a change in pump pressure for optimum performance  Varying water supply affects stream performance  Requires good communication between pump operator and nozzle operator  The need for Standard Operating Guidelines to provide for successful operations  Cannot easily change flow based on current fire conditions -- Limited choices  Changing size always requires a change in pump pressure for optimum performance  Varying water supply affects stream performance  Requires good communication between pump operator and nozzle operator  The need for Standard Operating Guidelines to provide for successful operations  Cannot easily change flow based on current fire conditions -- Limited choices

Is This Nozzle Really Flowing 95 GPM?  Determining factors are pump pressure, hose line friction loss, and therefore, nozzle pressure

Limitations of Fixed & Selectable Flow Nozzles... UNDER-pressured Stream  Less reach & penetration  Little power or “punch” to the stream  Fog pattern does not absorb as much heat, & provides less protection  Less reach & penetration  Little power or “punch” to the stream  Fog pattern does not absorb as much heat, & provides less protection 50 psi

Limitations of Fixed & Selectable Flow Nozzles... OVER-pressured Stream  Very difficult to handle  Stream may “break up”  Fog pattern may become “misty” & although dense, easily carried away  Greater nozzle reaction - without needed flow increase  Very difficult to handle  Stream may “break up”  Fog pattern may become “misty” & although dense, easily carried away  Greater nozzle reaction - without needed flow increase 150 psi

Nozzle Pressure - Fixed Flow Nozzles

Nozzle Pressure & Reaction Force...  Reaction force is a function of nozzle pressure and flow  At equal nozzle pressures, a higher flow will produce a greater reaction  At equal flows, a greater nozzle pressure will produce a greater reaction  Fixed flow nozzles produce rapid gains in nozzle reaction when only slight increases of flow are made, once rated flow is reached  Reaction force is a function of nozzle pressure and flow  At equal nozzle pressures, a higher flow will produce a greater reaction  At equal flows, a greater nozzle pressure will produce a greater reaction  Fixed flow nozzles produce rapid gains in nozzle reaction when only slight increases of flow are made, once rated flow is reached

Comparison of 150 GPM 75 psi 67.5 lb/f 100 psi79.2 lb/f 125 psi88.5 lb/f 150 psi97.2 lb/f 75 psi 67.5 lb/f 100 psi79.2 lb/f 125 psi88.5 lb/f 150 psi97.2 lb/f Nozzle Pressure Nozzle Reaction

Nozzle Pressure, Reaction, & Flow Single GPM Nozzle