- Fire sprinkler design for powder environmental room manual#
- Fire sprinkler design for powder environmental room plus#
Typically, a minimum safety factor of 10 psi is required.
When the required outside hose demand is added to the system flow demand (380 gpm + 250 hose = 630 gpm ) and plotted on a graph, t he available city water pressure is approximately 49 psi when flowing at 630 gpm. In the example scenario, t he water flow test indicate s pressures of 54 psi static, 48 psi residual, flowing at 940 gpm. The water flow test used to size the fire pump is required to have been complet ed within the last 12 months (NF PA 20 -2013, Section 4.6.1.2 ). Once a hazard analysis and preliminary hydraulic calculations have established the fire flow and pressure required to meet the standpipe or sprinkler system demand, a review of a recent water flow test can identify if a fire pump is necessary. A preliminary hydraulic calculation indicates a required system pressure of 90 psi. The estimated flow demand for this area is approximately 380 gpm (0.15 gpm x 1,950 square feet = 292.5 gpm + 30 % for sprinkler head overflow = 380 gpm ). T he remote area size is increased to 1,950 sq uare feet due to a 30% increase for slope s exceeding 2: 12 (NFPA 13 -2013, Section 11.2.3.2.4). Though the density for this remote area is only 0.15 gpm ( o rdinary h azard g roup 1), the top floor location requires additional pressure to overcome the head loss from elevation. The most hydraulically demanding area in this example is the l evel five mechanical room. A preliminary hydraulic calculation for this area indicates a required system pressure of 6 5 psi.
The estimated flow demand for this area is approx imately 507 gp m ( 0.20 gpm x 1,950 s quare feet = 39 0 gpm + 30% for sprinkler head overflow = 507 gpm ). It also requires a 30% increase to the remote area size because the system type must be dry due to exposure to freezing conditions (NFPA 13 -2013, Section 11.2.3.2.5). The exterior loading dock require s the second highest density : 0.20 gpm for o rd inary h azard g roup 2. For this reason, the calculated area need only extend to the perimeter walls of the room (NFPA 13 -2013, Section 11.2.3.3). The two-hour rated enclosure provides an effective barrier to prevent fire spread outside of the room. While the oxygen storage room requires the highest density (0.30 gpm for e xtra h azard o ccupancy), this space is not the most hydraulically demanding. The predominate hazard classification for the overall building is that of l ight h azard o ccupancy, h owever, the building contains spaces that warrant higher hazard designations.
Fire sprinkler design for powder environmental room manual#
The building is equipped with a Class I wet manual standpipe system. The center core area s on levels zero through four contain elevator lobbies, public corridor s and public restrooms. The fifth floor is a larg e mechanical penthouse with a roof slope of 3: 12. įloors one through four are comprised of offices, exam rooms and outpatient procedure rooms. The basement level contains electrical rooms, general storage rooms, a small oxygen storage room (250 s quare feet ) enclosed by a two-hour fire rating and a covered exterior loading dock. The building construction is non combustible, Type I I-B and e ach floor is approximately 18,000 square feet. It is important to perform a hazard analysis of the building before attempti ng to size the fire pump.įor example, a new sprinkler system might be installed in a five-story medical office building with a partial basement (overall building height of 69 feet ). Though the IBC requires buildings with a highest finished floor located more than 30 feet above the lowest fire department vehicle access to be equipped with Class III standpipes or Class I if the buildin g is fully sprinklered, NFPA 14 : Standard for the Installation of Standpipe and Hose Systems allows the standpipes to be manual type with the necessary pressure provided by the fire department pumper truck through the fire department connection (2013 NFPA 14, Section 5.4.1.1), thus eliminating the standpipe demand from consideration. įor non high-rise buildings, the most demanding area could be any number of different haz ards.
Fire sprinkler design for powder environmental room plus#
In many high-rise buildings, this can be the automatic fire standpipe system demand which requires 500 gallons per minute at 100 pounds per square inch at the top of the most remote standpipe, plus 250 gpm for each additional standpipe, up to a maximu m of 1,000 gpm for wet systems or 1,250 gpm for dry systems.
Because of the critical importance of the fire pump, careful consideration should be employe d when selecting and designing a fire pump.Ī fire pump’s size is dictated by the most hydraulically demanding area of the fire protection system.