Good day, im a beginner in fire protection design. i know how to hand calc a simple branched fire protection system, i have a question regrading this new design that i was working on. For me its my first challenge as designer.You can look at the primary design that i have made (with architects direction) i have attached a picture of it, my questions will be how can i calculate a system with looped and not looped branches?, where is the most remote area that i should consider ( you can see a 3 rectangular shape 1500sq.ft in area that im considering to get the most demand). Thank you. Lastly since the building is a Mercantile classification i designed it Ordinary Hazard 1 where the are of protection of a sprinkler is 130sq.ft x 0.15gpm/ sq.ft = 19.5 gpm then if you tried to find the pressure in the most remote sprinkler using the required flow of it that, (19.5/8)^2 = 5.94psi (its below the 7psi minimum of NFPA 13). Im thinking of using 10psi for the most remote sprinkler to be safe, is it better to have 10psi at the very end sprinkler or just 7 psi?. Again thank you for helping. God bless.