[Code of Federal Regulations]
[Title 46, Volume 1]
[Revised as of Octobery 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 46CFR39.20-9]

[Page 505-506]
 
                           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:
    (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

[[Page 506]]

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]