HomeMy WebLinkAboutFire Flow LetterErika Bridges, EIT, CFM
City of College Station
Planning & Development Services
PO Box 9960
College Station, TX 77842
RE: CS/SD #9 FIRE FLOW LETTER
Dear Erika:
MITCHELL
MM
MORGAN
March 14, 2014
The purpose of this letter is to address the required fire flow for the 9th Elementary School for
the College Station School District. The new elementary school will be constructed of Type 11-B
construction with a total square footage of 85,246 square feet. The building will be separated
into 2 buildings by a 2 hour fire wall. The maximum square footage of these 2 portions is
64,697 square feet, including all 3 building alternates. All portions of the building will be
protected with a fire sprinkler system, allowing us to take a 50% reduction in required fire flow.
According to Table B105.1 of the International Fire Code (attached) the required fire flow for
Type 11 -B construction for 64,697 square feet is 5,250 gpm, reduced by 50% results in a fire flow
of 2,625 gpm. According to the Site Design Standards for the City of College Station, a flow
greater than 2,250 gpm but less than 3,000 gpm is required to be split between a minimum of
three hydrants. We have included 3 hydrants on our site, equally spaced around the building
and each one being fed by an 8-inch line.
As you are aware, this project is surrounded by the Bridgewood Subdivision which is being
designed by McClure & Browne Engineers. Dale Browne has modeled our 3 fire hydrants in his
water model for the subdivision and has found that each hydrant can flow the required 875
gpm with a velocity less than 12 fps in the 8-inch lines and with pressures maintained above 20
psi.
You should have a copy of this fire flow report for the Bridgewood Subdivision in which you can
verify these assumptions and results. Please feel free to contact me if you should have any
qu
or
Managing Partner
Attachment
511 UNIVERSITY DRIVE EAST, SUITE 204 • COLLEGE STATION, TX 77840 • T 979.260.6963 • F 979.260.3564
CIVIL ENGINEERING HYDRAULICS • HYDROLOGY • UTILITIES STREETS • SITE PLANS • SUBDIVISIONS
info@mitchellandmorgan.com • www.m1tchellandmorgan.com
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,I
APPENDIX B
TABLE 8105.1
MINIMUM REQUIRED FIRE-FLOW ANO FLOW DURATION FOR BUILDINGS
FIRE-FLOW CALCULATION AREA (square feel) FIRE-FLOW FLOW DURATION
Type IA and 1s• Type llA and lllA" Type IV and V-A• Type llB and lllB' TypeV-B' (gallons per minute)0 (hours)
0-22,700 0-12.700 0-8,200 0-5,900 0-3,600 I.500
22,701-30,200 12.701 -17,000 8.201-10,900 5,901-7,900 3.601-4,800 1,750
30,201-38. 700 17,001 -21,800 10,901-12.900 7,901-9,800 4,801-6.200 2,000 2 38.701-48.300 21,801 -24,200 12,901-17 .400 9,801-12,600 6,201 -7.700 2,250
48,301-59.000 24,201 -33,200 17,401-21.300 12.601-15,400 7,701-9,400 2,500
59,001-70,900 33.201 -39.700 21.301-25,500 15,401-18,400 9,401-11.300 2.750
70,901-83,700 39,701 -47.100 25.501-30,100 18.401-21. 800 11,301-13.400 3,000
83,701 -97.700 47,101 -54,900 30,101-35,200 21,801-25 .900 13,401-15,600 3,250 3 97.701-112,700 54.901-63,400 35,201-40.600 25,901-29.300 15,601-18,000 3,500
112,701-128,700 63.401 -72.400 40,601-46,400 29,301-33,500 18,001-20,600 3,750
128,701-145,900 72,401-82.100 46.401-52,500 33,501 -37,900 20.601-23,300 4.000
145.901-164.200 82, 101-92. 400 52.501-59,100 37,901-42.700 23,301-26.300 4,250
164.201-183.400 92.401-103,100 59.101-66,000 42.701-47.700 26,301-29,300 4,500
183.401-203,700 103.101-114.600 66,001-73,300 47,701-53.000 29,301-32,600 4.750
203. 701 -22 5 .200 114,601 -126,700 73,301-81, 100 53,001-58,600 32,601-36,000 5.000
225,201 -247,700 126,701-139,400 81, 101-89,200 58,601 -65,4{)0 36.001-39.600 5.250
247.701 -271,200 139,401-152.600 89.201-97,700 65,401-70.600 39.601-43.400 5,500
271.201-295,900 152,601-166.500 97. 701-106,500 70,601-77.000 43,401-47,400 5,750
295,901-Greater 166.501-Greater 106.501-115,800 77.001-83,700 47,401-51.500 6.000 4
·--115,801-125,500 83.701 -90,600 51.501-55.700 6,250
--125,501-135,500 90,601-97,900 55,701-60.200 6.500
--135,50 l-145,800 97.901-106,800 60,201-64,800 6.750
--145,801-156.700 106.801·113.200 64,801-69,600 7.000
--156,701-167,900 113,201-121.300 69,601-74,600 7.250
--167.90H 79,400 121,301-129,600 74.601 -79.800 7,500
--179.401-191.400 129,601-138,300 79,801-85,100 7,750
-191,401-Greater 138,301-Greater 85,101-Greater 8,000
For SI: I square foot • 0.0929 m2. I gallon per minute • 3.785 Lim. l pound per square inch " 6.895 k.Pa.
a. Types of construction are based on the lntemalionaf Building Code.
b. Measured at 20 psi residual pres.~ure.
Exhibit 1
446 2012 INTERNATIONAL FIRE CODE•