[Code of Federal Regulations]
[Title 46, Volume 4]
[Revised as of October 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 46CFR98.25-40]

[Page 86-87]
 
                           TITLE 46--SHIPPING
 
    CHAPTER I--COAST GUARD, DEPARTMENT OF TRANSPORTATION (CONTINUED)
 
PART 98--SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK--Table of Contents
 
                Subpart 98.25--Anhydrous Ammonia in Bulk
 
Sec. 98.25-40  Valves, fittings, and accessories.

    (a) All valves, flanges, fittings and accessory equipment shall be 
of a type suitable for use with anhydrous ammonia and shall be made of 
steel, or malleable or nodular iron meeting the requirements of 
Sec. 56.60-1 of subchapter F (Marine Engineering) of this chapter. 
Valves shall be fitted with noncorrosive material suitable for ammonia 
service. Valves, flanges, and pipe fittings shall be of the square or 
round tongue and groove type or raised-face, United States of America 
Standard 300-pound standard minimum, fitted with suitable soft gasket 
material. Welded fittings shall be used wherever possible and the number 
of pipe joints shall be held to a minimum. Screwed joints are not 
permitted for pipe diameters exceeding 2 inches. Nonferrous materials, 
such as copper, copper alloys and aluminum alloys, shall not be used in 
the construction of valves, fittings or accessory equipment. Brazed 
joints are prohibited.
    (b) Each tank shall be provided with the necessary fill and 
discharge liquid and vapor shut-off valves, safety relief valves, liquid 
level gaging devices, thermometer well and pressure gage, and shall be 
provided with suitable access for convenient operation. Connections to 
tanks installed below the weather deck shall be made to a trunk or dome 
extending above the weather deck. Connections to the tanks shall be 
protected against mechanical damage and tampering. Other openings in the 
tanks, except as specifically permitted by this part, are prohibited.
    (c) All connections to the tanks, except safety devices and liquid 
level gaging devices, shall have manually operated shut-off valves 
located as close to the tank as possible.
    (d) Excess flow valves where required by this section shall close 
automatically at the rated flow of vapor or liquid as specified by the 
manufacturer. The piping, including valves, fittings and appurtenances, 
protected by an excess flow valve, shall have a greater capacity than 
the rated flow of the excess flow valve.
    (e) Liquid level gaging devices which are so constructed that 
outward flow of tank contents shall not exceed that

[[Page 87]]

passed by a No. 54 drill size opening, need not be equipped with excess 
flow valves.
    (f) Pressure gage connections need not be equipped with excess flow 
valves if the openings are not larger than No. 54 drill size.
    (g) Excess flow valves may be designed with a bypass, not to exceed 
a No. 60 drill size opening, to allow equalization of pressure.
    (h) Prior to disconnecting shore lines, the pressure in the liquid 
and vapor lines shall be relieved through suitable valves installed at 
the loading header.
    (i) Relief valves shall be fitted in liquid lines which may be 
subject to excessive pressure caused by liquid full condition, and the 
escape from the relief valves shall be piped to the venting system.
    (j) The pressure gage shall be located at the highest practical 
point. The thermometer well shall terminate in the liquid space and be 
attached to the shell by welding with the end of the fitting being 
provided with a gas-tight screwed plug or bolted cover.

[CGFR 65-50, 30 FR 17022, Dec. 30, 1965, as amended by CGFR 68-82, 33 FR 
18902, Dec. 18, 1968; CGFR 70-10, 35 FR 3712, Feb. 25, 1970]