CFR

76.25-10—Size and arrangement of sprinkler heads and pipe sizes.

(a) General. (1) The system shall be so designed and arranged that the overhead is effectively sprayed and that all portions of the deck are covered.

(2) One-half inch sprinkler heads shall be used. Sprinkler heads shall be so arranged that no portion of the overhead or vertical projection of the deck is more than 7 feet from a sprinkler head.

(b) Pipe sizes. (1) The sizes of branch lines, single cross mains, feed mains, and risers shall be in proportion to the number of sprinkler heads served. The minimum pipe sizes shall be as given in table 76.25-10(b)(1).

Table 76.25-10(b)(1)

Minimum nominal pipe size, inches	Maximum number of heads served
Minimum nominal pipe size, inches	Vessels whose construction is more combustible than that set forth in §§ 72.05-5 through 72.05-60	Vessels constructed in general agreement with §§ 72.05-5 through 72.05-60
1	2	2
11/4	3	3
11/2	5	5
2	10	10
21/2	20	40
3	40	250
31/2	65
4	100
5	160
6	250

(2) If a complete loop cross main is employed, the size of such cross main shall be in proportion to the number of sprinkler heads served. The minimum pipe sizes shall be as given in table 76.25-10(b)(2). The entire loop shall be of the same size pipe.

Table 76.25-10(b)(2)

Minimum nominal pipe size, inches	Maximum number of heads served
Minimum nominal pipe size, inches	Vessels whose construction is more combustible than that set forth in §§ 72.05-5 through 72.05-60	Vessels constructed in general agreement with §§ 72.05-5 through 72.05-60
1	5	5
11/4	9	9
11/2	13	13
2	22	30
21/2	40	80
3	80	250
31/2	130
4	250

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