Leak means any of several events that indicate interruption of confinement of vinyl chloride within process equipment. Leaks include events regulated under subpart V of this part such as:
(1) An instrument reading of 10,000 ppm or greater measured according to Method 21 (see appendix A of 40 CFR part 60);
(2) A sensor detection of failure of a seal system, failure of a barrier fluid system, or both;
(3) Detectable emissions as indicated by an instrument reading of greater than 500 ppm above background for equipment designated for no detectable emissions measured according to Method 21 (see appendix A of 40 CFR part 60); and
(4) In the case of pump seals regulated under § 61.242-2, indications of liquid dripping constituting a leak under § 61.242-2.
(x) Exhaust gas means any offgas (the constituents of which may consist of any fluids, either as a liquid and/or gas) discharged directly or ultimately to the atmosphere that was initially contained in or was in direct contact with the equipment for which gas limits are prescribed in §§ 61.62(a) and (b); 61.63(a); 61.64 (a)(1), (b), (c), and (d); 61.65 (b)(1)(ii), (b)(2), (b)(3), (b)(5), (b)(6)(ii), (b)(7), and (b)(9)(ii); and 61.65(d). A leak as defined in paragraph (w) of this section is not an exhaust gas. Equipment which contains exhaust gas is subject to § 61.65(b)(8), whether or not that equipment contains 10 percent by volume vinyl chloride.
(y) Relief valve discharge means any nonleak discharge through a relief valve.
(z) 3-hour period means any three consecutive 1-hour periods (each commencing on the hour), provided that the number of 3-hour periods during which the vinyl chloride concentration exceeds 10 ppm does not exceed the number of 1-hour periods during which the vinyl chloride concentration exceeds 10 ppm.
40 CFR § 61.61
Terms used in this subpart are defined in the Act, in subpart A of this part, or in this section as follows: