UL 2129:2017 pdf free download – STANDARD FOR SAFETY Halocarbon Clean Agent Fire Extinguishers.
7.7 For the purpose of these requirements, thickness measurements of the sidewall are to be measured on uncoated metal. The thickness of the dome and of the bottom is to be measured at several points after forming and before coating.
8 Joints
8.1 The minimum width of a brazed joint on the cylinder wall shall not be less than four times the design
thickness of the sidewall.
9 Caps, Valves, Closures, and Pressure Relief
9.1 The inside diameter of a fill opening of a rechargeable-type extinguisher shall be:
a) A minimum 19 mm (3/4 in) for an extinguisher having a capacity of 13.6 kg (30 Ib) or less;
Exception: For coated cylinders, a minimum 38 mm (1-1/2 in) fill opening is required.
b) A minimum 64 mm (2-1/2 in) for an extinguisher having a capacity above 13.6 kg (30 Ib).
9.2 A collar with external threads shall be constructed so that the cap does not contact the dome or the bottom when the gasket is removed.
9.3 A threaded cap, closure, or valve shall engage the collar or the threaded opening by a minimum four full threads with the gasket in place.
9.4 A cap, plug, or other component, except a pressure gauge or indicator, shall be provided with a means of relieving pressure when it is removed while the agent chamber is still under pressure. The pressure shall be relieved with a minimum two threads engaged.
9.5 Closures of rechargeable extinguishers shall resist, without evidence of damage to the threads, a closing torque of 35 N.m (25 lbt-ft).
9.6 When pressure relief is required under the jurisdiction of the U.S. Department of Transportation (DOT) or Canada Transportation of Dangerous Goods Regulations (TDGR), it shall be in accordance with the Compressed Gas Association pamphlet CGA S-1.1 Pressure Relief Device Standards.
10 Gaskets and “0” Rings
10.1 A gasket or an “0” ring shall be retained in a recess or the equivalent, in the cap, collar, or valve.
A gasket or an “0” ring of a rubber-like material shall be of thickness to provide a compression-type seal
and shall fit snugly against the cap or head. See Elastomeric Parts Test, Clause 44.
11 Filling Density
11.1 The maximum ratio of extinguisher agent mass to cylinder volume (filling density) shall be specified
by the manufacturer.
12 Pressure Gauges and Indicators
12.1 A rechargeable extinguisher, including a wheeled extinguisher, of the stored pressure type employing a single chamber for both the agent and the expellant gas shall be equipped with a pressure gauge to show the amount of pressure in the chamber whether the valve is open or closed, except as provided in 12.2. The operating range of the gauge shall reflect the operating temperature-pressure relationship of the extinguisher, except that the minimum operating pressure line is able to be higher than the pressure that corresponds to the minimum operating temperature. A bourdon tube type pressure gauge shall have a pressure relief that vents in the event of a bourdon tube leak.
12.2 An extinguisher having a disposable, nonrefillable, sealed chamber is not required to be equipped with a pressure gauge when a pressure indicator is used to verify that the extinguisher is charged with the correct expellant gas pressure.
12.3 The pressure gauge face shall indicate the appropriate units for which the gauge is calibrated, such as psig, or kPa, or bar, or any combination of pressure units.