HomeMy WebLinkAboutFire Flow AnalysisCarol Cotter, EIT
City of College Station
Planning & Development Services
P.O. Box 9960
College Station, TX 77840
MITCHELL
M M
MORGAN
RE: New College Hills Elementary -Fire Flow Analysis
Dear Carol:
April 2, 2008
Below is the fire flow analysis for the new College Hills Elementary School to be located on
Williams Street between Francis Drive and Gilchrist Avenue, which will replace the existing
elementary school at that location. The new school will be approximately 82,200 square
feet, with the largest area between fire walls of 61,500 square feet. The new school will be
constructed of Type llB materials and equipped with an automatic fire suppression sprinkler
system.
A domestic flow of 177 .35 gpm was calculated by comparing the average daily water use
rates to the proposed usage rates of Creekview Elementary on a square footage basis. This
comparison was made because the schools are similar sizes and will be constructed around
the same time. Because the school will be evacuated at the time of a fire, the domestic
flow for the school was not placed on the site during fire flow conditions. The fire code
requires a 2625 gpm fire flow as calculated using the Fire Flow Requirements as shown on
page 10 of the May 2006 City of College Station Site Design Standards (Exhibit 7) and a
50% sprinkler reduction. The site will be served by three fire hydrants as shown on Exhibit
2.
The updated City of College Station water system MikeNET model was checked against a
flow test performed on Williams Street near the existing College Hills Elementary assuming
a six inch (6") waterline is currently within Williams. It was found that model results
(average day conditions) were reasonably close to those found by flow tests under both
static and residual conditions. Please see Exhibit 3 for the hydrant flow test report and
Exhibit 4 for a map showing the tested hydrants.
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
Flow Test and MikeNET Comparison
Method Static Residua/ Demand
Flow Test 88.00 psi 80.00 psi 1300 gpm
MikeNET 102.00 psi 88.60 psi 1300 gpm
The City of College Station water system MikeNET model was updated with the proposed
waterlines, and then used to model fire flow conditions. It is unclear whether the existing
line within Williams Street is a six (6") or an eight (8") inch waterline. Because the size is
not yet known, a scenario was modeled for both line sizes to determine the effect of the
existing line on the system. When the fire hydrant is constructed as part of the new
Co llege Hills Elementary School project we will know if the waterl ine in Williams is six (6")
or eight (8") inches in size. Please see Exhibit 5 (Scena rio 1) for the fire flow conditions
modeled with an existing 6" waterline in Williams, and Exhibit 6 (Scenario 2) with an
existing 8" waterline at this location.
Eight (8") inch waterlines will serve the site as shown in Exhibit 2. The 2625 gpm fire flow
was evenly split between the three on-site fire hydrants; two on Williams Street and one
located adjacent to building in the proposed parking lot. It was found that in Scenario 1
pressures in the surrounding waterlines remained above 20 psi, and velocities in all but one
line remained below 12 fps . A velocity of 17.5 fps was found in the existing waterline on
Williams Street, modeled as a six inch (6") waterline in this scenario. In Scenario 2 (existing
8" on Williams) pressures remained above 20 psi, and all velocities were below 12 fps.
In the case that the waterline within Williams Street is a six inches (6") in diameter, we
would like to request the ability to exceed the design velocity requirement of 12 fps for this
186 linear feet of waterline.
If you have any comments, or would like to discuss our find ings further, please feel free to
contact me .
Managing Partner
cc: file
Mike Ball -CSISD
S:\Proj\0739-CollegeHillsRenovations-VLK\docs\0739-fireflow.doc
Fire Service Standards
limited to banquet halls, night clubs, restaurants, taverns, and bars that exceed 5,000
square feet in area shall require an automatic sprinkler system. A Fire Department
Connection (FDC) is required for all buildings utilizing an automatic sprinkler system.
The FDC must be located within 150 feet of a fire hydrant.
Fire Flow Requirements
In general, the calculation area for fire flow requirements is based on the total gross
area of the structure, including any area under the horizontal projections of the roof of
the structure. Portions of the building that are separated by fire walls without
openings and constructed in accordance with the International Building Code, may be
considered as separate areas for the purposes of fire flow calculations. For type IA
and type IB construction, the calculation shall be based on the area of the three
largest successive floors.
MINIMUM REQUIRED FIRE FLOW ANO FLOW DURATION FOR BUILDINGS•
FIRE-FLOW CALCULATION AREA (oquaro l .. 1)
Tvoe IA and 1e• TVoe llA tnd biA0 'fype IV and V-A• Tvoe 118 and 1110• T11oev-e•
0-22,700 0-12.700 0-8,200 0-5,900 0-3,600
22,701-30,200 12.701-17.000 8.201-10.900 5,901-7.900 3,601-4,800
30.201-38.700 l 7.001. 2),800 10.901-12,900 7.901-9.800 4,801 -6.200
38,701-48.300 21,801-24.200 12.901-17,400 9.801-12.600 6,201-7,700
48.301-59.000 24,20 I· 33.200 17.401-21.300 12.601-15,400 7,701-9,400
59,001-70.900 33,201-39.700 21,301-25.500 15,401-18,400 9,401-11,300
70.90 l-83, 700 39.701-47.100 25,501-30. l 00 18.401-21.800 11 .. 301-13.400
83.701-97,700 47,101-54,900 30, I 0 I ·35.200 21,801-25.900 13,401-15,600
97.701-112.700 54.9-01-63,400 35,201-40.600 25,90 l · 29 .300 15,601-18,000
112,70 1-128,700 63.401 -72,400 40,601-46,400 29,301 ·33.500 18,001-20,600
128.701-145.900 72.401-82.100 46,40!-52.500 33,501-37.900 20,601-23.300
145,901-164.200 82.101-92.400 52.50 1-59.100 37,901-42,700 23.301-26.300
164,201-183,400 92,401-103,100 59,101-66,000 42,701-4 7 700 26,301-29 300
183.401-203,700 103,lOl-114,600 66,001-73,300 47 .70 I ·53,000 29,30 J -32 .• 600
203,701-225,200 114.601-126.700 73,301 -81 ,100 53.00 L,58.600 32,601-36,000
225,201-247.700 126.701-139.400 81,101 -89,200 58,601-65.400 36.001-39.600
247,701-271.200 139.401-152.600 89.201-97.700 65,40 I· 70.600 39.601-43,400
271,20 1-295,900 152.60 I· l 66.500 97 701-106,500 70,601-77 .000 43,401-47 ,400
295,90 I ·Grealcr 166,50 I-Greater 106,501-115,800 77.001-83.700 47.401-51.500
--115 .. 801-125.500 83.701-90,600 5 UOJ ·55.700
--125.501-135.500 90.601-97,900 55.70 I ·60.200
--135,501-145.800 97.90 1-106,800 60,201-64,800
--145.801-156 700 106.801·113,200 64,801-69.600
--156.701-167,900 113.201-121,300 69.601-74.600
--167,901-179,400 121,301-129,600 74.601· 79.800
--179,401 -191,400 129,60I·138,300 79,801-85,100
--191,401-Gre:ller l 38,301-Greater 85,IOl·Grci1ter
For SI: 1 sc1u:il'C fool "'0.()1)29 m1, 1 gallon per mi nu le• 3.78S IJm, I pound per Ul"""' inch • 6.895 kl'o. I a. ·n.e minimum required fire Onw shall be permi11«1 10 be reduced hy 25 perccnl for Group R.
b. Types of conSlru<:lion on: based on lhe /11tm111tinnal Building Code.
c:. Measured a1 20 psi.
-10 .
FIRE FLOW
llaolk>na a.r mlnuto1•
1,500
1,750
2,000
2.250
2.500
2.750
3.000
J.250
3.500
3,750
4,000
4,250
4,500
4.750
5,000
5,250
5,500
5,750
6,000
6,250
6.500
6,750
7.000
7.250
7500
7,750
8,000
FLOW
DURATION !hours\
2
3
4
EXHIBIT 1
College Station Utilities
Reliable, Affordable, Community Owned
Date Thursday, February 07, 2008
Time 9:15AM
Test
completed by Matthew Matcek
Witness AJ Daily
Location College Hills Elementery
Nozzle size 2.5
Flow hydrant D-132
Pitot reading 60
G.P.M. 1300
Static hydrant D-133
Static PSI 88
Residual PSI 80
Comments
EXHIBIT 3
This set of data has been prepared for the use of
the city and its employees and has no official
status. The accuracy of the data is limited to the
validity of the data and therefore the City makes
no representation or warranties as to the accuracy
of the data. Any party using the data does so at
their own risk.
r
/
EXHIBITS
MikeNET Analysis
Project Description: Steady State, Fireflow Conditions, No domestic flow on College Hills, fireflow of2625 split on 3 hydrants,
6" ex isti ng WL on Wi lliams
... / / / /
•' ' .. ~· ,.
I (
( ( f -
/" ' /
/
i
/,.·
2'365
·,2368 . , '
/
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-------< .~-...... \/ .t ..
..
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. ----------\. ,/
\."\ .. \~---,.
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EXHIBIT 5
Results -Junctions
Time Level: O; 0 day 0:00 hr
Number of Junctions: 16(Selection) ----
Junction ID Elevation Demand Grade Pressure
[ft] [gpmj [ft] [psi]
83 312.000 69 .313 380.203 29.5 53
2357 310.000 0.000 413 .808 44.980
2360 303.000 0.000 409.370 46.090
2361 312.000 875.000 363.197 22.1 84
,---
2362 292.000 0.000 414.555 53.103
2363 294.000 0.000 415 .095 52.470
2364 296.000 0.000 412.813 50.615
2365 306.000 0.000 404.73 1 42.780
2370 312.000 0.000 373 .749 26.756
I --
2371 312.000 0.000 366.613 23.664
1307.500 I o.ooo '
2372 363.030 I 24.061
r---,------,
2373 308.000 0.000 362.715 23.708
2374 307.500 I o.ooo 362.053 23.638
2375 305.500 I 875.ooo , 359.169 I 23.255
2376 305 .500 0.000 359.169 23 .255
r-
2377 305.250 875.000 378.510 31.744
EXHIBIT 5
r
Results -Pipes
Time Level: O; 0 day 0:00 hr
Number of Pipes: 16(Selection)
Pipe ID Node I Node 2 Diameter Length Roughness Flow Velocity Head loss
[in) [ft] [millift] [gpm] lft/s] [ft]
2028 83 2370 8.000 306.202 130.000 1080.403 6.896 6.454
2757 2357 2360 8.000 296.054 130.000 898.8 11 5.737 4.438
2758 2360 2377 6.000 185.988 130.000 1544.597 17.527 30.860
2759 2360 2362 8.000 637.934 130.000 -645.786 -4.122 5.184
2760 2362 2363 8.000 66.475 130.000 -645.786 -4.122 0.540
2761 2363 2364 6.000 397.530 130.000 251.183 2.850 2.282
2762 2365 83 8.000 748.104 110.000 1149.7 16 7.338 24.527
2763 2364 2365 6.000 1407.701 130.000 251.183 2.850 8.082
2770 2370 2371 8.000 338.564 130.000 1080.403 6.896 7.137
277 1 2371 2361 8.000 162.050 130.000 1080.403 6.896 3.416
2772 2372 2361 6.000 42.096 130.000 -205.403 -2.331 0.166
,-
2773 2372 2373 8.000 22.134 130.000 875.000 5.585 0.316
.-------· -
2774 2373 2374 8.000 46.386 130.000 875.000 5.585 0.662
2775 2374 2375 8.000 202.161 130.000 875.000 5.585 2.884 ---
2776 2375 2376 8.000 33.549 130.000 -0.000 -0.000 0.000
2778 2377 2372 6.000 438.666 130.000 669.597 7.598 15.480
EXHIBIT 5
EXHIBIT6
MikeNET Analysis
Project Description: Steady State, Fire flow Conditions, o domestic fl ow on College Hills, fireflow of 2625 split on 3 hydrants,
8" exi sting WL on Williams
EXHIBIT 6
. .
Results -Junctions
Time Level: O; 0 day 0:00 hr
Number of Junctions: l 6(Selection)
r
Junction ID Elevation Demand Grade Pressure Quality
[ft] [gpm] [ft] [psi]
83 312.000 69.313 396.244 36.503 0.000
2357 310.000 0.000 409.741 43 .218 0.000
2360 303.000 0.000 404.550 44.001 0.000
236 1 312.000 875.000 386.679 32.358 0.000
2362 292.000 0.000 413 .267 G .545 0.000
i---
2363 294.000 0.000 414.175 52.072 0.000
2364 I 296.ooo 0.000 41 3.387 I 5o.864 0.000 .--
41 o.596 I 45 .322 2365 306.000 0.000 0.000
2370 312.000 0.000 392.614 34.930 0.000
237 1 I 312.000 0.000 388.600 133 .191 0.000
2372 1307.500 0.000 ' 386.710 134.322 0.000
,--
2373 308.000 0.000 I 386.394 I 33.968 0.000
2374 1307.500 0.000 I 385.733 133.898 0.000
1305.500 I ' 382.849 133.515 I o.ooo 2375 875.000
1305.500
I I 382.849 133.515
.-----
2376 0.000 0.000
I 305.250 394.113 138.504
--
23 77 875.000 0.000
EXHIBIT 6
...
Results -Pipes
Time Level: O; 0 day 0:00 hr
Number of Pipes: l 6(Selection) ,--
Pipe ID Node 1 Node 2 Diameter Length Roughness Flow Velocity Headloss
[in] [ft) [millift) [gpm) [ft/s) [ft)
2028 83 2370 8.000 306.202 130.000 791.860 5.054 3.630
2757 2357 2360 8.000 296.054 130.000 978.188 6.244 5.191
2758 2360 2377 8.000 185.988 130.000 1833.141 11.701 10.437
2759 2360 2362 8.000 637.934 130.000 -854.953 -5.457 8.717
2760 2362 2363 8.000 66.475 130.000 -854.953 -5.457 0.908
r--
276 1 2363 2364 6.000 397.530 130.000 141.459 1.605 0.788
--,--,----
2762 2365 83 8.000 748.104 110.000 861.1 73 5.497 14.352
2763 2364 2365 6.000 1407.701 130.000 141.459 1.605 2.791
2770 2370 2371 8.000 338.564 130.000 791.860 5.054 4.014
--r--
1791.860 2771 237 1 2361 8.000 162.050 130.000 5.054 1.921
,--
2772 2372 2361 6.000 42.096 130.000 83.140 0.943 0.031
2773 I 2312 2373 8.000 22.134 130.000 875.000 5.585 0.3 16
2774 I 2373 I 2374 8.000 46.386 130.000 I 875.ooo 5.585 0.662
2775 2374 2375 8.000 202.161 130.000 875.000 5.585 2.884
2776 2375 2376 8.000 33.549 130.000 0.000 0.000 0.000
---I 6.116 2778 2377 2372 8.000 438.666 130.000 958.14 1 7.403
--
EXHIBIT 6
r
Drainage Area
Drainage Area (sq mi)
DA1 0.112295
DA2 0.052976
DA3 0.066568
DA4 0.0332
DA5 0.0453
DA6 0.017771
JA 0.112295
JB 0.165271
JC 0.265039
JD 0.310339
JE 0.32811
R1 0.112295
R2 0.165271
R3 0.265039
R4 0.310339
College Hills
Increased Impervious Cover
During Transition Phase Analysis
Existing Conditions
Peak Runoff Time To Peak Runoff Volume
(cfs) (date,hours:minutes) (inches)
299.6 01 Jan2008, 12:40 9.5
172.4 01 Jan2008, 12:26 9.21
206.4 01Jan2008, 12:30 9.47
89.6 01Jan2008, 12:38 9.52
169.3 01Jan2008, 12:20 9.66
75.4 01Jan2008, 12:14 9.38
299.6 01Jan2008, 12:40 9.5
432.5 01Jan2008, 12:36 9.41
664.5 01 Jan2008, 12:40 9.44
7 49.3 01 Jan2008, 12:40 9.47
767.2 01Jan2008, 12:44 9.46
294.8 01 Jan2008, 12:44 9.5
402.5 01Jan2008, 12:48 9.41
656.2 01 Jan2008, 12:44 9.44
742.4 01Jan2008, 12:44 9.47
DA4 is the school site drainage area
JE is the Junction at the end of the analysis at University Oaks
Transition Conditions (Existing School and New Slab)
Drainage Area Peak Runoff Time To Peak Runoff Volume
Drainage Area (sq mi) (cfs) (date,hours:minutes) (inches)
DA1 0.112295 299.6 01Jan2008, 12:40 9.5
DA2 0.052976 172.4 01 Jan2008, 12:26 9.21
DA3 0.066568 206.4 01Jan2008, 12:30 9.47
DA4 0.0332 89.8 01Jan2008, 12:38 9.58
DA5 0.0453 169.3 01 Jan2008, 12:20 9.66
DA6 0.017771 75.4 01Jan2008, 12:14 9.38
JA 0.112295 299.6 01Jan2008, 12:40 9.5
JB 0.165271 432.5 01Jan2008, 12:36 9.41
JC 0.265039 664.7 01Jan2008, 12:40 9.44
JD 0.310339 749.5 01Jan2008, 12:40 9.48
JE 0.32811 767.4 01Jan2008, 12:44 9.47
R1 0.112295 294.8 01Jan2008, 12:44 9.5
R2 0.165271 402.5 01Jan2008, 12:48 9.41
R3 0.265039 656.4 01Jan2008, 12:44 9.44
R4 0.310339 7 42 .6 01 Jan2008, 12:44 9.48