[Code of Federal Regulations]
[Title 46, Volume 2]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 46CFR56.50-70]

[Page 207-208]
 
                           TITLE 46--SHIPPING
 
   CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)
 
PART 56_PIPING SYSTEMS AND APPURTENANCES--Table of Contents
 
    Subpart 56.50_Design Requirements Pertaining to Specific Systems
 
Sec. 56.50-70  Gasoline fuel systems.

    (a) Material. (1) Fuel supply piping to the engines shall be of 
seamless drawn annealed copper pipe or tubing, nickel copper, or copper 
nickel pipe or tubing meeting the requirements of subpart 56.60.
    (2) Tubing wall thicknesses shall not be less than the larger of 
that shown in Table 56.50-70(a), or as required by Sec. 56.07-10(e) and 
104.1.2 of ANSI-B31.1.
    (3) Tubing fittings shall be of nonferrous drawn or forged metal and 
of the flared type except that the flareless fittings of the nonbite 
type may be used when the tubing system is of nickel copper or copper 
nickel. Tubing shall be cut square and flared by suitable tools. Tube 
ends shall be annealed before flaring. Pipe fittings shall be of 
nonferrous material. Pipe thread joints shall be made tight with a 
suitable compound.
    (4) Valves for fuel lines shall be of nonferrous material of the 
union bonnet type with ground seats except that cocks may be used if 
they are the solid bottom type with tapered plugs and union bonnets.

                Table 56.50-70(a)--Tubing Wall Thickness
------------------------------------------------------------------------
                                                          Thickness
       Outside diameter of tubing in inches        ---------------------
                                                      B.W.G.      Inch
------------------------------------------------------------------------
\1/8\, \3/16\, \1/4\..............................        0.032
                                                           21
\5/16\, \3/8\.....................................         .035
                                                           20
\7/16\, \1/2\.....................................         .042
                                                           19
------------------------------------------------------------------------

    (b) Installation. (1) All fuel pipes, pipe connections, and 
accessories shall be readily accessible. The piping shall run in sight 
wherever practicable, protected against mechanical injury, and 
effectively secured against excessive movement and vibration by the use 
of soft nonferrous metal liners or straps without sharp edges. Where 
passing through steel decks or bulkheads, fuel lines shall be protected 
by close fitting ferrules or stuffing boxes. Refer to Sec. 56.30-25 for 
tubing joint installations.

[[Page 208]]

    (2) A short length of suitable metallic or nonmetallic flexible 
tubing or hose, or a loop of annealed copper tubing shall be installed 
in the fuel supply line at or near the engine to prevent damage by 
vibration. If nonmetallic flexible hose is used it shall meet the 
requirements of Sec. 56.60-25(b) for fuel service. Flexible hose 
connections should maintain metallic contact between the sections of the 
fuel supply lines; however, if such contact is not maintained, the fuel 
tank shall be grounded.
    (3) Valves in fuel lines shall be installed to close against the 
flow.
    (c) Shutoff valves. Shutoff valves of a suitable type shall be 
installed in the fuel supply lines, one as close to each tank as 
practicable, and one as close to each carburetor as practicable. Where 
fuel tanks are installed below the weather deck, arrangements shall be 
provided for operating all shutoff valves at the tanks from outside the 
compartments in which they are located, preferably from an accessible 
position on the weather deck. The operating gear for the shutoff valves 
at the tanks shall be accessible at all times and shall be suitably 
marked.
    (d) Strainers. A suitable twin strainer shall be fitted in the fuel 
supply line in the engine compartment. Strainers shall be of the type 
opening on top for cleaning screens. A drip pan shall be fitted under 
the strainer.
    (e) Outlets and drains. Outlets in fuel lines for drawing gasoline 
for any purpose are prohibited. Valved openings in the bottom of fuel 
tanks are prohibited; however, openings fitted with threaded plug or cap 
can be used for cleaning purposes.
    (f) Fuel suction connections. All fuel suction and return lines 
shall enter the top of the fuel tanks and connections shall be fitted 
into spuds. Such lines shall extend nearly to the bottom of the tank.
    (g) Filling and sounding pipes. Filling and sounding pipes shall be 
so arranged that vapors or possible overflow when filling cannot escape 
to the inside of the vessel but will discharge overboard. Such pipes 
shall terminate on the weather deck clear of any coamings and shall be 
fitted with suitable shutoff valves or deck plugs. Filling and sounding 
pipes shall extend to within one-half of their diameter from the bottom 
of the tank or from the surface of the striking plate in case of a 
sounding pipe. A flame screen of noncorrodible wire mesh shall be fitted 
in the throat of the filling pipe. Sounding pipes shall be kept closed 
at all times except during sounding.
    (h) Vent pipes. Each tank shall be fitted with a vent, the cross-
sectional area of which shall not be less than that of the filling pipe. 
The vent pipes shall terminate at least 2 feet above the weather deck 
and not less than 3 feet from any opening into living quarters or other 
below deck space. The ends of vent pipes shall terminate with U-bends 
and shall be fitted with flame screens or flame arresters. The flame 
screens shall consist of a single screen of corrosion resistant wire of 
at least 30 by 30 mesh.
    (i) Gasoline tanks. For requirements pertaining to independent 
gasoline fuel tanks see subpart 58.50 of this subchapter.
    (j) Fuel pumps. Each fuel pump must be equipped with controls as 
required by Sec. 58.01-25 of this subchapter.

[CGFR 68-82, 33 FR 18843, Dec. 18, 1968, as amended by CGFR 69-127, 35 
FR 9978, June 17, 1970; CGFR 72-59R, 37 FR 6189, Mar. 25, 1972; CGD 83-
043, 60 FR 24774, May 10, 1995; USCG-2002-13058, 67 FR 61278, Sept. 30, 
2002]