ESFR fire sprinkler system with additional in rack sprinklers This fire sprinkler installation was installed into major car manufactures parts facility and is somewhat bespoke in its design. The roof level sprinklers are ESFR 25mm with a K-factor of 360 and a minimum head pressure of 3.5 bars. In addition, the rack storage bellow is protected with 20mm sprinkler with a K-factor of 115 and a minimum head pressure of 1.0 bar. The final water demand requirements for the system was 9849 Lpm @ 9.0 bar and this was with a 98% design efficiency. The FHC hydraulic model consisted of 810 pipes, 154 loops and 26 heads and was calculated on an old Pentium VI computer under 0.1 seconds.