[Code of Federal Regulations]
[Title 46, Volume 7]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 46CFR182.450]

[Page 278]
 
                           TITLE 46--SHIPPING
 
   CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)
 
PART 182_MACHINERY INSTALLATION--Table of Contents
 
                Subpart D_Specific Machinery Requirements
 
Sec. 182.450  Vent pipes for fuel tanks.

    (a) Each unpressurized fuel tank must be fitted with a vent pipe 
connected to the highest point of the tank.
    (b) The net cross sectional area of the vent pipe for a gasoline 
fuel tank must not be less than that of 19 millimeters (0.75 inches) 
outer diameter (O.D.) tubing (0.9 millimeter (0.035 Inch) wall 
thickness, 20 gauge), except that, where the tank is filled under 
pressure, the net cross sectional area of the vent pipe must be not less 
than that of the fill pipe.
    (c) The minimum net cross sectional area of the vent pipe for diesel 
fuel tanks must be as follows:
    (1) Not less than the cross sectional area of 16 millimeters (0.625 
inches) outer diameter (O.D.) tubing (0.9 millimeter (0.035-inch) wall 
thickness, 20 gauge), if the fill pipe terminates at the top of the 
tank;
    (2) Not less than the cross sectional area of 19 millimeters (0.75 
inches) O.D. tubing (0.9 millimeter (0.035-inch) wall thickness, 20 
gauge), if the fill pipe extends into the tank; and
    (3) Not less than the cross sectional area of the fill pipe if the 
tank is filled under pressure.
    (d) The discharge ends of fuel tank vent pipes must terminate on the 
hull exterior as high above the waterline as practicable and remote from 
any hull openings, or they must terminate in U-bends as high above the 
weather deck as practicable and as far as practicable from openings into 
any enclosed spaces. Vent pipes terminating on the hull exterior must be 
installed or equipped to prevent the accidental contamination of the 
fuel by water under normal operating conditions.
    (e) The discharge ends of fuel tank vent pipes must be fitted with 
removable flame screens or flame arresters. The flame screens must 
consist of a single screen of corrosion resistant wire of at least 30x30 
mesh. The flame screens or flame arresters must be of such size and 
design as to prevent reduction in the net cross sectional area of the 
vent pipe and permit cleaning or renewal of the flame screens or 
arrester elements.
    (f) A vessel of not more than 19.8 meters (65 feet) in length 
carrying not more than 12 passengers, with fuel gasoline tank vents 
built in accordance with ABYC Project H-24, or 33 CFR 183, subpart J, or 
with diesel fuel tank vents built in accordance with ABYC Project H-33, 
will be considered as meeting the requirements of this section.
    (g) Where a flexible vent pipe section is necessary, suitable 
flexible tubing or hose having high resistance to salt water, petroleum 
oils, heat and vibration, may be used. Such hose must overlap metallic 
pipe ends at least 1\1/2\ times the pipe diameter and must be secured at 
each end by clamps. The flexible section must be accessible and as near 
the upper end of the vent pipe as practicable.
    (h) Fuel tank vent pipes shall be installed to gradient upward to 
prevent fuel from being trapped in the line.