[Code of Federal Regulations]
[Title 46, Volume 1]
[Revised as of January 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 46CFR39.20-9]

[Page 513-514]
 
                           TITLE 46--SHIPPING
 
         CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY
 
PART 39_VAPOR CONTROL SYSTEMS--Table of Contents
 
                   Subpart 39.20_Design and Equipment
 
Sec. 39.20-9  Tank barge liquid overfill protection--B/ALL.

    Each cargo tank of a tank barge must have one of the following 
liquid overfill protection arrangements.
    (a) A system meeting the requirements of Sec. 39.20-7 of this part 
which:
    (1) Includes a self-contained power supply;
    (2) Is powered by generators installed on the barge; or
    (3) Receives power from a facility and is fitted with a shore tie 
cable and a 120 volt 20 amp explosion-proof plug which meets:
    (i) ANSI/NEMA WD6;
    (ii) NFPA 70, Articles 410-57 and 501-12; and
    (iii) Sec. 111.105-9 of this chapter.
    (b) An intrinsically safe overfill control system which:
    (1) Is independent of the cargo gauging device required by Sec. 
39.20-3(a) of this part;
    (2) Actuates an alarm and automatic shutdown system at the facility 
overfill control panel, or on the vessel to be lightered if a lightering 
operation, 60 seconds before the tank becomes 100 percent liquid full;
    (3) Is able to be checked at the tank for proper operation prior to 
each loading;
    (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 Sec. 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 and R1 for the tank overfill sensor 
circuit, pin G connected to the cabling shield, and pins N and T3 
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.
    (c) A spill valve which:

[[Page 514]]

    (1) Meets ASTM F 1271 (incorporated by reference, see Sec. 39.10-
5);
    (2) Relieves at a pressure higher than the pressure at which the 
pressure relief valves meeting the requirements of Sec. 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).

[CGD 88-102, 55 FR 25446, June 21, 1990, as amended by CGD 95-072, 60 FR 
50462, Sept. 29, 1995; CGD 96-041, 61 FR 50727, Sept. 27, 1996; USCG-
2000-7790, 65 FR 58459, Sept. 29, 2000]