46CFR Part 39 Vapor Control Systems
Subpart 39.20 Design and Equipment
§ 39.20-9 Tankship liquid overfill protection -T/ALL (continued)

OVERFILL PROTECTION (continued)

(4) Consists of components which, individually or in series, will not generate or store a total of more than 1.2 V, 0.1 A, 25 mW, or 20 microjoules;

(5) Has at least one tank overfill sensor switch with normally closed contacts per cargo tank;

(6) Has all tank overfill sensor switches connected in series;

(7) Has interconnecting cabling that meets 111.105-15(b) of this chapter; and

(8) Has a male plug with a 5 wire, 16 amp connector body meeting IEC 309-1/309-2 which is:

(i) Configured with pins S2(L2) and Rl(LI) for the tank overfill sensor circuit, pin G connected to the cabling shield, and pins N and T3(L3) reserved for an optional high level alarm circuit meeting the requirements of this paragraph; and

(ii) Labeled "Connector for Barge Overflow Control System" and with the total inductance and capacitance of the connected switches and cabling.

"API Recommended Practice 1125 also applies to the wiring of Liquid Level Sensors."

(c) A spill valve which:

(1) Meets ASTM F1271;

(2) Relieves at a pressure higher than the pressure at which the pressure relief valves meeting the requirements of 39.20-11 operate;

(3) Limits the maximum pressure at the cargo tank top during liquid overfill, at the maximum loading rate for the tank, to not more than the maximum design working pressure for the tank; and

(4) If the vessel is in ocean or coastwise service, has provisions to prevent opening due to cargo sloshing.

(d) A rupture disk arrangement which meets paragraphs (c) (2), (c) (3) and (c) (4) of this section and is approved by the Commandant (G-MSO).