Section 76.23-10 - Quantity, pipe sizes, and discharge rates(a)General.(1) The system shall be so designed and arranged that the overhead is effectively sprayed and all portions of the deck are covered. The capacity shall be such that at least 12 gallons of water per minute are applied to each 100 square feet of deck area.(2) Piping, fittings, sprinkler heads, and pumps installed in accordance with the remainder of this section will be considered as meeting the above requirements. If alternate sizes or arrangements are used, it shall be demonstrated that these minimum requirements have been met.(b)Sprinkler heads.(1) Three-eighth inch open type sprinkler heads shall be used. Sprinkler heads shall be so arranged that no portion of the overhead is more than 7 feet from a sprinkler head.(c)Pipe sizes.(1) The various pipe sizes shall be in proportion to the number of heads served. Minimum pipe sizes shall be as given in table 76.23-10(c). Table 76.23-10(c)
| Number of 3/8 inch heads served | Minimum nominal pipe sizes, inches |
| Over | Not over |
| 1 | 3/4 |
| 1 | 2 | 1 |
| 2 | 4 | 11/4 |
| 4 | 6 | 11/2 |
| 6 | 12 | 2 |
| 12 | 18 | 21/2 |
| 18 | 30 | 3 |
| 30 | 46 | 31/2 |
| 46 | 66 | 4 |
| 66 | 120 | 5 |
(d)Fire pumps.(1) The fire pumps may be used for the sprinkling system provided there is sufficient total capacity to operate the largest zone of the sprinkling system with a Pitot tube pressure of at least 15 p.s.i. at all heads and at the same time to deliver water from the two highest fire hose outlets in a manner similar to that described in § 76.10-5(c) . In addition, on vessels over 750 gross tons, there shall be sufficient pumping capacity to also operate the second largest zone.