House Water Supply. Continued

Description

This section is from the book "A Working Manual Of American Plumbing Practice", by William Beall Gray, Charles B. Ball. Also available from Amazon: Plumbing.

House Water Supply. Continued

Table I

Head in feet	Pressure pounds per square inch
1	.43
2	.86
3	1.30
4	1.73
5	2.16
6	2.59
7	3.03
8	3.46
9	3.89
10	4.33
11	4.76
12	5.20
13	5.63
14	6.06
15	6.49
16	6.92
17	7.36
18	7.79
19	8.22
20	8.66
21	9.09
22	9.53
23	9.96
24	10.39
25	10.82
26	11.26
27	11.69
28	12.12
29	12.55
30	12.99
31	13.42
32	13.86
33	14.29
34	14.72
35	15.16
36	15.59
37	16.02
38	16.45
39	16.89
40	17.32
41	17.75
42	18.19
43	18.62
44	19.05
45	19.49

Head in feet	Pressure pounds per square inch
46	9.92
47	20.35
48	20.79
49	21.22
50	21.65
51	22.09
52	22.52
53	22.95
54	23.39
55	23.82
56	24.26
57	24.69
58	25.12
59	25.55
60	25.99
61	26.42
62	26.85
63	27.29
64	27.72
65	28.15
66	28.58
67	29.02
68	29.45
69	29.88
70	30.32
71	30.75
72	31.18
73	31.62
74	32.05
75	32.48
76	32.92
77	33.35
78	33.78
79	34.21
80	34.65
81	35.08
82	35.52
83	35.95
84	36.39
85	36.82
86	37.25
87	37.68
88	38.12
89	38.55
90	38.98

Head in feet	Pressure pounds per square inch
91	39.42
92	39.85
93	40.28
94	40.72
95	41.15
96	41.58
97	42.01
98	42.45
99	42.88
100	43.31
101	43.75
102	44.18
103	44.61
104	45.05
105	45.48
106	45.91
107	46.34
108	46.78
109	47.21
110	47.64
111	48.08
112	48.51
113	48.94
114	49.38
115	49.81
116	50.24
117	50.68
118	51.11
119	51.54
120	51.98
121	52.41
122	52.84
123	53.28
124	53.71
125	54.15
126	54.58
127	55.01
128	55.44
129	55.88
130	56.31
131	56.74
132	57.18
133	57.61
134	58.04
135	58.48

Table II

Friction Loss in lb. per sq. in., per 100 ft. of Clean Iron Pipe of Sizes

Given, Together with Number Gallons Discharged per min., and Velocity of Flow of Water per sec.

GALLONS DISCHARGED (per sines)	Velocity . (ft. per soc)	Friction Lose Ob.)	VELOCITY (ft per sec.)	Friction Lou (lb.)	Velocity (ft. per sec )	Friction Lou (lb.)	VELOCITY (ft. per sec.)	Friction Loss (lb.)	VELOCITY (ft. per sec.)	Friction Lou (lb)	Velocity (ft. per sec.)	Friction Leas (lb.)	Cals. Discmaeosp (per sain.)
GALLONS DISCHARGED (per sines)	1/2 -IN. PIPE		4+in. Pipe		ton. Pipe		1 1/2-IN. Pipe		1 1/2-IN. Pipe		2-IN. Pipe		Cals. Discmaeosp (per sain.)
6	8.17	24.6	3.63	3.3	2.04	0.84	1.31	0.31	0.91	0.12			5
10	16.30	96.0	7.25	13.0	4.08	3.16	2.61	1.05	1.82	0.47	1.02	0.12	10
15	...........	.....	10.90	28.7	6 13	6.98	3 92	2.38	2.73	0.97			15
20	...........	...	14.50	50.4	8.17	12.3	5.22	4.07	3.63	1.66	2.04	6.42	20
25	...........	...........	18.10	78.0	10.20	19.0	6.53	6.40	4.54	2.62	..........	..........	25
30	...........	...........	...........	...........	12.30	27.50	7.84	9.15	5.45	3.75	3.06	0.91	30
35	...........	...........	...........	...........	14.30	37.0	9.14	12.40	6.36	5.05	....	....	35
40	...........	...........	...........	...........	16.30	48.0	10.40	16.10	7.26	6.52	4.09	1.60	40
45	...........	...........	...........	...........	...........	...........	11.70	20.20	8.17	8.15	....	....	45
50	...........	...........	...........	...........	...........	...........	13.10	24.90	9.08	10.00	5.11	2.44	50
75	...........	...........	...........	...........	...........	...........	19.60	56.10	13 60	22 40	7.66	5.32	75
100	...........	...........	...........	...........	...........	...........	...........	...........	18.20	39.00	10.20	9.46	100
125	...........	...........	...........	...........	...........	...........	...........	...........	..........	..........	12.80	14.90	125
150	...........	...........	...........	...........	...........	...........	...........	...........	....	..........	15.30	21.20	150
175	...........	...........	...........	...........	...........	...........	...........	...........	..........	..........	17.10	28.10	175
200	...........	...........	...........	...........	...........	...........	...........	............	..........	..........	20.40	37.50	200
	2 1/2-IN. PIPE		3-in. Pipe		4-IN. PlPE		6-IN. Pipe		8-in. Pipe		10-IN. Pipe
25	1.63	0.21	1.13	0.10	...........	...........	...........	...........	...........	...........	...........	...........	25
50	3.26	0.81	2.27	0.35	1. 28	0.09	...........	...........	...........	...........	...........	...........	50
75	4.90	1.80	3.40	0.74	...........	...........	...........	...........	...........	...........	...........	...........	75
100	6.53	3 20	4.54	1.31	2.55	6.33	1.13	0.05	...........	...........	...........	...........	100
125	8.16	4.89	5.67	1.99	...........	...........	...........	....	...........	...........	...........	...........	125
150	9.80	7.00	6.81	2.85	3.83	0.69	1.70	0.10	...........	...........	...........	...........	150
175	11.40	9 46	7.94	3 85	...........	...........	...........	...........	...........	...........	...........	...........	175
200	13.10	12.47	9.08	5.02	5.11	1.22	2.27	0.17	...........	...........	...........	...........	200
250	16.30	19.66	11.30	7.76	6 39	1.89	2.84	0.26	1.59	0. 07	1.02	0.03	250
300	19.60	28.06	13.60	11.20	7.66	2.66	3.40	0.37	...........	...........	...........	...........	300
350	...........	...........	15.90	15 20	8.94	3.65	3.97	0.50	...........	...........	...........	...........	350
400	...........	..........	18.20	19.50	10.20	4.73	4.54	0.65	...........	...........	...........	...........	400
450	...........	...........	20 40	25 00	11.50	6.01	5.11	0.81	...........	...........	...........	...........	450
500	...........	...........	22.70	30.80	12.80	7.43	5 67	0.98	3.19	0.25	2.04	0.09	500
750	...........	...........	...........	...........	...........	...........	8.51	2 21	4 79	0.53	3.06	0.18	750
1000	...........	...........	...........	...........	...........	...........	11.30	3.88	6.38	0.94	4.08	0.32	1000
1250	...........	...........	...........	...........	...........	...........	...........	...........	7.97	1.46	5.10	0.49	1250
1500	...........	...........	...........	...........	...........	...........	...........	...........	9.57	2. 09	6.12	0.70	1500
1750	...........	...........	...........	...........	...........	...........	...........	...........	...........	...........	7.15	0.95	1750
2000	...........	...........	...........	...........	...........	...........	...........	...........	...........	...........	8.17	1.23	2000

The friction due to fittings is generally taken to equal straight additional pipe for each as follows: 90° ells, 40 diameters; pipe entering tee, 60 diameters; pipe entering coupling, 20 diameters, and, interposing a globe valve, 60 diameters.

Examples, A l 1/2-inch pipe 100 feet long connected with a cistern is to discharge 35 gallons per minute. At what elevation above the end of the pipe must the surface of the water in the cistern be to produce this flow?

In Table II we find the friction loss for a 1 1/2-inch pipe discharging 35 gallons per minute to be 5.05 pounds. In Table I we find a pressure of 5.2 pounds corresponds to a head of 12 feet, which is approximately the elevation required.

How many gallons will be discharged through a 2-inch pipe 100 feet long where the inlet is 22 feet above the outlet? In Table I we find a head of 22 feet corresponds to a pressure of 9.53 pounds. Then, looking in Table II, we find in the column of Friction Loss for a 2-inch pipe that a pressure of 9.46 corresponds to a discharge of 100 gallons per minute.

Tables I and II are commonly used together in examples.

A house requiring a maximum of 10 gallons of water per minute is to be supplied from a spring which is located 600 feet distant, and at an elevation of 50 feet above the point of discharge. What size of pipe will be required? From Table I we find an elevation or head of 50 feet will produce a pressure of 21.65 pounds per square inch. Then 'if the length of the pipe were only 100 feet, we should have a pressure of 21.65 pounds available to overcome the friction in the pipe, and could follow along the line corresponding to 10 gallons in TableII until we came to the friction loss corresponding most nearly to 21.65, and take the size of pipe corresponding. But as the length of the pipe is 600 feet, the friction loss will be six times that given in Table II for given sizes of pipe and rates of flow; hence we must divide 21.65 by 6 to obtain the available head to overcome friction, and look for this quantity in the table, 21.65÷6=3.61, and Table II shows us that a 1-inch pipe will discharge 10 gallons per minute with a friction loss of 3.16 pounds, and this is the size we should use.

Examples For Practice

1. What size pipe will discharge 40 gallons per minute, a distance of 50 feet, with a pressure head of 19 feet?Ans. 1 1/4-inch gallons, multiplication by the decimal may be omitted, and dividing by 294 instead of 231 will then give the same result.

2. What head will be required to discharge 100 gallons per minute through a 2 1/2-inch pipe 700 feet long? Ans. 52 feet

In calculating the contents of pipes, cylinders, and cisterns, where it is usual to correct the area found as a result of squaring the diameter by multiplying by .7854, before dividing by 231 for U. S.

Continue to:

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House Water Supply. Continued

Description

House Water Supply. Continued

Table I

Table II

Examples For Practice

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