A nozzle reaction force of 75 lbs. force is the upper limit for two firefighters on a handline to manage the nozzle. This is the reaction force from an automatic fog nozzle at 150 gpm |
Nationally, 150 has become the target flow for 1 3/4 inch handlines. This number comes NFPA 1710. The standard outlines that the first two handlines in operation at any initial structure fire flow be a minimum of 300 gpm combined.
This comes from http://www.fireapparatusmagazine.com/content/fa/en/articles/print/volume-16/issue-8/features/benefits-of-conduction-a-nozzle-study-equipment-and-operations.html and http://www.firedistrict7.com/tpdffiles/nozleproject/NozzlePresentation.pdf
Grimwood's study has outlines the number of firefighters required to safely counter nozzle reaction
one firefighter for 60 lbs. force
two firefighters for 75 lbs. force
three firefighters for for 95 lbs. force
These are the working limits to safely managing the nozzle reaction.
This is not how many firefighters should be on the handline for hose advancement or management, but how many should be directly behind the nozzle to support the reaction.
The reaction force from an automatic fog nozzle at 200 gpm is 100 lbs The reaction force from an automatic fog nozzle at 250 gpm is 125lbs |
