Diameter Of Radiator Connections. Direct Radiation. Fall Of Temperature, 20&Deg;

Size of pipe in inches...................

3/4

1

1 1/4

1 1/2

2

2 1/2

Area in square feet ......................

16

24

40

60

120

240

The sectional area of the mains should approximate the sum of the area of its tranches, but in many cases, particularly where there is no indirect work, the sizes may be a little less.

The fittings used on hot-water mains should all have easy curves and the branches should be Y's, to reduce resistance to a minimum. Special distributing fittings should be used to induce circulation through radiators on the first floor.

Sizes Of Mains And Branches

Sizes of Main. Sizes of Branches.

1"

will supply two 3/4".

li"

will supply two 1"; or one 1" and two 3/4".

li"

will supply two l 1/4"; or one li" and two 1".

2"

will supply two li"; or one l 1/2" and two li".

2 1/2"

will supply two li" and one li"; or one 2" and one l 1/4".

3"

will supply one 2 1/2" and one 2"; or two 2" and one 1 1/2".

3i"

will supply two 2 1/2"; or one 3" and one 2": or three 2".

4"

will supply one 3i" and one 2 1/2" or two 3"; or four 2".

4 1/2"

will supply one 3i" and one 3"; or one 4" and one 2 1/2".

5"

will supply one 4" and one 3"; or one 4 1/2" and one 2 1/2".

6"

will supply two 4" and one 3"; or four 3"; or ten 2".

7"

will supply one 6" and one 4"; or three 4" and one 2".

8"

will supply two 6" and one 5"; or five 4" and two 2".

All flow and return pipes should be of the same size.

All pipes must rise from the boiler to the radiators with a pitch of at least 1 in. in 10 ft.

The expansion-tank capacity should be at least 1/20 that of the entire apparatus, if it is an open tank. Closed tanks are not to be recommended.

Radiating Surface Supplied By Hot-Water Risers. Direct Radiation. Fall Of Temperature, 20&Deg;

Diameter of

Riser.

Inches.

Story Where Heater is Located.

1

2

3

4

5

6

3/4

12

17

21

24

1

22

32

40

48

l 1/4

38

56

70

80

88

l 1/2

66

92

112

132

145

2

140

196

238

280

310

2 1/2

240

328

400

470

515

3

350

490

595

700

770

850

3 1/2

510

705

860

1,010

1,110

1,215

4

700

980

1,190

1,280

1,540

1,660

There is a practical limit to the advantageous vertical length of risers, especially with the smaller pipes. If a small riser extends to a great height, the friction becomes excessive, and the quantity of water delivered will be much smaller than it would otherwise be.

Limiting Height of Risers.

Diameter in inches.........................

3/4

1

1 1/4

1 1/2

2

Height in feet .................................

20

30

45

60

80

The horizontal pipes on the upper floors of a building, and also the risers leading thereto, may be made smaller in diameter than those upon the lower floors, because the force which impels the water increases with the height of the circuits. The proper size of a pipe having been determined for a given service on the first floor, the diameter for equal service on higher floors - the temperatures remaining the same - may be found by multiplying by the following factors:

Story.................................................. 2d 3d 4th 5th

Factor .................................................87 .80 .76 .73

The area of heating surface that may be properly supplied by a pipe of given diameter will increase as the circuit is made higher. If the area which is known to be right for a given size of pipe on the first floor, be taken as 1, the areas on the upper floors will increase in the following order:

Story............................................. 2d 3d 4th 5th

Proper area heating surface......... 1.40 1.70 1.98 2.20