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Fire Protection

Sprinkler Hydraulics

Hydraulic calculation of a tree or gridded sprinkler system by the node method of a calculation sheet: the most remote head at its minimum pressure, Q = K√p at every head, Hazen–Williams friction (4.52 Q^1.85 / (C^1.85 d^4.87) per foot, with the SI form), fittings as loss coefficients turned into equivalent lengths, elevation at 0.433 lb/in² per foot, side branches balanced by their K_eq at each junction, a gridded system balanced by Hardy Cross, and an exact nodal solution of the same network beside the sheet. The demand (sprinklers plus hose allowance) is set against the hydrant-test supply curve on the N^1.85 relation, with the pump boost if the supply is short. The density, design area and hose allowance are entered: the NFPA 13 density–area curve is where the analyst reads them; the defaults are the light-hazard values of UFC 3-600-01 Table 9-3 (0.10 gpm/ft² over 1,500 ft², K 5.6) and Table 9-4 (250 gpm hose) on an illustrative twelve-head tree.

1 worked example reproduced, listed on the tool page.

Fire Dynamics Calculations

Compartment and pool-fire dynamics by the closed-form methods of the NRC handbook NUREG-1805, Fire Dynamics Tools, as revised in its Supplement 1: hot gas layer temperature (McCaffrey, Quintiere and Harkleroad for natural ventilation; Foote, Pagni and Alvares and Deal and Beyler for forced ventilation; Beyler for a closed compartment) with the Yamana and Tanaka smoke-layer height; pool-fire heat release rate, burning duration and flame height (Heskestad, Thomas); radiant heat flux to a target by the point-source and solid-flame models, with and without wind (Mudan tilted flame); Heskestad plume temperature and velocity and the Alpert ceiling jet; sprinkler, heat-detector and smoke-detector activation by the response time index; flashover heat release rate (MQH, Babrauskas, Thomas), Law's post-flashover temperature and fire severity; ignition and cable damage time (Tewarson, Mikkola and Wichman, Quintiere and Harkleroad, Janssens, Toal); smoke filling and visibility (Jin); and the SFPE hydraulic egress model. Material, fuel, cable and smoke-yield properties come from the handbook's tables; the default case is NUREG-1805 Example Problem 2-1.

1 worked example reproduced, listed on the tool page.

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