Page 124 - Water Engineering Hydraulics, Distribution and Treatment

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Chapter 4
Quantities of Water Demand
For management:
+ Q
Q
= Q
= 590 + 913 = 1,503 gpud.
max day
domestic
sprinkling
By Eq. (4.21a): Q
= 334 + 2.02Q
= 334 + 2.02 × 1,503 = 3,640 gpud.
max day
peak h
For design based on 200 dwellings:
From Table 4.11: Q
= 1,503 + 0.4(1,000) = 1,903 gpud.
max day
= 3,640 + 0.7(1,000) = 4,340 gpud.
From Table 4.11: Q
peak h
Solution 2 (SI System):
Average maximum and peak daily domestic demands per dwelling unit:
By Eq. (4.20b): Q = 594 + 13.1 MF = 594 + 13.1 × 125 × 1.0 = 2,232 Lpud.
domestic
By Eq. (4.19b): A = 1.016 D −1.26 = 1.016∕(7.415) 1.26 = 1.016∕12.4836 = 0.08138 ha∕unit.
By Eq. (4.18b): Q sprinkling = 6,003 A(E − P) = 6,003 × 0.08138 × (7.11 − 0)
= 3,473 Lpud excluding precipitation.
For management:
Q max day = Q domestic + Q sprinkling = 2,232 + 3,473 = 5,705 Lpud.
By Eq. (4.21b): Q peak h = 1,264 + 2.02 Q max day = 1,264 + 2.02 × 5,705.2 = 12,789 Lpud.
For design based on 200 dwellings:
From Table 4.11: Q max day = 5,705 + 0.4 (1,000) × 3.785 = 7,219 Lpud.
From Table 4.11: Q peak h = 12,789 + 0.7 (1,000) × 3.785 = 15,438 Lpud.
EXAMPLE 4.4 DETERMINATION OF FIRE FLOW AND DURATION FOR BUILDINGS
2
2
A four-story wooden-frame building (combustible, unprotected) has each floor of area 5,490 ft (510 m ). This wooden building is
2
2
adjacent to a five-story building of commercial construction (noncombustible, protected) with 9,800 ft (910 m ) per floor. Determine
the fire flow and duration (a) for four-story building; (b) for five-story building; and (c) for both buildings assuming they are connected
together.
Solution 1 (US Customary System):
2
a. Area occupied by the four-story building = 4 (5,490) = 21,960 ft .
From Table 4.13, column Type V-B,
Fire flow = 4,000 gpm and duration = 4h.
2
b. Area occupied by the five-story building = 5 (9,800) = 49,000 ft .
From Table 4.13, column Type I-A,
Fire flow = 2,500 gpm and duration = 2h.
2
c. Total area of two buildings = 21,960 + 49,000 = 70,960 ft .
Fractional area of the four-story building = 21,960/70,960 = 0.3095.
Fractional area of the five-story building = 49,000/70,960 = 0.6905.