15-16-451 Test pipes for high-rise buildings.

   In high-rise buildings the test pipe for a sprinkler system may be placed at the water flow switch or the valve controlling the sprinklers for an individual floor or portion of a floor. The test connection shall be a listed sight test connection utilizing an orifice equivalent to a sprinkler of a type having the smallest orifice used in the system. The test connection shall terminate at a drain capable of accepting full flow of one sprinkler under system pressure.

(Added Coun. J. 10-30-96, p. 31216, § 1)

15-16-460 Dry pipe systems.

   A dry pipe system shall be permitted only where heat is not adequate to prevent freezing of water in all or sections of a system. If the sprinklers in such unheated spaces are 25 percent or less of the total number of sprinklers required on a system having a total of 100 or more sprinklers, only such 25 percent or less shall be on the dry system and the remainder shall be on the wet system.

   The dry pipe system shall be isolated from the water supplies (or from the wet portion of the system, if a combined wet and dry pipe system) by a dry pipe valve located at an accessible point as near as practicable to the dry system, adequately protected against mechanical injury and freezing.

(Prior code §  91-30; Amend Coun. J. 10-30-96, p. 31216, § 1)

15-16-470 Dry pipe system capacity limits.

   No more than 500 sprinklers shall be controlled by one dry pipe valve. The capacities given below for various sizes of pipe shall be used to calculate the capacity of a system.

Capacity Per Foot of Pipe
Diameter	Gallons
	Schedule 40	Schedule 10
1 in.	.045	.049
1 1/4 in.	.078	.085
1 1/2 in.	.106	.115
2 in.	.174	.190
2 1/2 in.	.248	.283
3 in.	.383	.433
3 1/2 in.	.513	.576
4 in.	.660	.740
5 in.	1.040	1.144
6 in.	1.501	1.649
8 in.	2.66	2.776

 

   Gridded dry pipe systems shall not be permitted.

(Prior code §  91-31; Amend Coun. J. 10-30-96, p. 31216, § 1)

15-16-480 Quick opening devices.

   Dry pipe valves controlling systems having a capacity of more than 500 gallons shall be provided with a quick opening device. The quick opening device shall be located as close as possible to the dry pipe valve while providing protection to the restriction orifice and other operating parts against submergence in water resulting from system drainage or priming. A soft disc globe or angle valve shall be installed in the connection between the dry pipe valve and the quick opening device. A check valve shall be provided also in the connection between quick opening device and the intermediate chamber of the dry pipe valve to prevent the escape of water if the dry valve should trip with the quick opening device disconnected. If the quick opening device requires a pressure feedback from the intermediate chamber, a valve type that will clearly indicate whether it is opened or closed shall be permitted in place of the check valve.

(Prior code §  91-32; Amend Coun. J. 10-30-96, p. 31216, § 1)

15-16-490 Non-freezing systems.

   Sprinkler piping in small unheated areas exposed to frost shall be filled with pure glycerine solution only. The total number of sprinklers in such areas shall not exceed 20. A durable sign or metal tag shall be firmly attached to the solution filling connection plainly marked “THE CITY CODE REQUIRES THE USE OF A PURE GLYCERINE SOLUTION ONLY”.

   The sprinklers on the piping filled with glycerine shall be below the interface between the water and antifreeze solutions provided that sprinklers may be located above the interface between the water and the antifreeze when a check value with a one-thirty-second inch hole in the clapper is provided in a U-loop. A water control valve and two small solution test valves shall be provided.

(Prior code §  91-33; Amend Coun. J. 10-30-96, p. 31216, § 1)

15-16-500 Gauges.

   There shall be provided dial spring pressure gauges in each sprinkler system on the riser above and below the alarm valve if so equipped, at the system main drain; at each main drain associated with a floor control valve; at the pressure tanks and in each independent pipe from the air supply to dry pipe systems.

   Gauges shall be graduated from zero to a pressure approximately double the normal working pressure of the system to which they are connected. Pressure gauges shall have a connection to the sprinkler system not less than one-quarter inch. Each gauge connection shall be equipped with a shutoff valve and provision for draining.

(Prior code §  91-34; Amend Coun. J. 10-30-96, p. 31216, § 1)

15-16-510 Relief valves.

   A brass relief valve not less than one and one-half inches in size shall be installed at the filling pump, set to relieve pressures ten percent in excess of the pressure at the pump when the pressure tank is under normal working pressure.

   A brass relief valve not less than three-fourths inch in size set to relieve pressures ten percent in excess of the normal pressure shall be installed in the air pipe between the check valve and the air compressor.

(Prior code §  91-35; Amend Coun. J. 10-30-96, p. 31216, § 1)