[Code of Federal Regulations] [Title 40, Volume 24] [Revised as of July 1, 2004] From the U.S. Government Printing Office via GPO Access [CITE: 40CFR264.1056] [Page 391] TITLE 40--PROTECTION OF ENVIRONMENT CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PART 264_STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES--Table of Contents Subpart BB_Air Emission Standards for Equipment Leaks Sec. 264.1056 Standards: Open-ended valves or lines. (a)(1) Each open-ended valve or line shall be equipped with a cap, blind flange, plug, or a second valve. (2) The cap, blind flange, plug, or second valve shall seal the open end at all times except during operations requiring hazardous waste stream flow through the open-ended valve or line. (b) Each open-ended valve or line equipped with a second valve shall be operated in a manner such that the valve on the hazardous waste stream end is closed before the second valve is closed. (c) When a double block and bleed system is being used, the bleed valve or line may remain open during operations that require venting the line between the block valves but shall comply with paragraph (a) of this section at all other times.