Terms used in this subpart are defined in the Act, in subpart A of this part, or in this section as follows:

(a) Ethylene dichloride plant includes any plant which produces ethylene dichloride by reaction of oxygen and hydrogen chloride with ethylene.

(b) Vinyl chloride plant includes any plant which produces vinyl chloride by any process.

(c) Polyvinyl chloride (PVC) plant includes any plant where vinyl chloride alone or in combination with other materials is polymerized.

(d) Slip gauge means a gauge which has a probe that moves through the gas/liquid interface in a storage or transfer vessel and indicates the level of vinyl chloride in the vessel by the physical state of the material the gauge discharges.

(e) Type of resin means the broad classification of resin referring to the basic manufacturing process for producing that resin, including, but not limited to, the suspension, dispersion, latex, bulk, and solution processes.

(f) Grade of resin means the subdivision of resin classification which describes it as a unique resin, i.e., the most exact description of a resin with no further subdivision.

(g) Dispersion resin means a resin manufactured in such a way as to form fluid dispersions when dispersed in a plasticizer or plasticizer/diluent mixtures.

(h) Latex resin means a resin which is produced by a polymerization process which initiates from free radical catalyst sites and is sold undried.

(i) Bulk resin means a resin which is produced by a polymerization process in which no water is used.

(j) Inprocess wastewater means any water which, during manufacturing or processing, comes into direct contact with vinyl chloride or polyvinyl chloride or results from the production or use of any raw material, intermediate product, finished product, by-product, or waste product containing vinyl chloride or polyvinyl chloride but which has not been discharged to a wastewater treatment process or discharged untreated as wastewater. Gasholder seal water is not inprocess wastewater until it is removed from the gasholder.

(k) Wastewater treatment process includes any process which modifies characteristics such as BOD, COD, TSS, and pH, usually for the purpose of meeting effluent guidelines and standards; it does not include any process the purpose of which is to remove vinyl chloride from water to meet requirements of this subpart.

(l) In vinyl chloride service means that a piece of equipment either contains or contacts a liquid that is at least 10 percent vinyl chloride by weight or a gas that is at least 10 percent by volume vinyl chloride as determined according to the provisions of § 61.67(h). The provisions of § 61.67(h) also specify how to determine that a piece of equipment is not in vinyl chloride service. For the purposes of this subpart, this definition must be used in place of the definition of “in VHAP service” in subpart V of this part.

(m) Standard operating procedure means a formal written procedure officially adopted by the plant owner or operator and available on a routine basis to those persons responsible for carrying out the procedure.

(n) Run means the net period of time during which an emission sample is collected.

(o) Ethylene dichloride purification includes any part of the process of ethylene dichloride purification following ethylene dichloride formation, but excludes crude, intermediate, and final ethylene dichloride storage tanks.

(p) Vinyl chloride purification incudes any part of the process of vinyl chloride production which follows vinyl chloride formation.

(q) Reactor includes any vessel in which vinyl chloride is partially or totally polymerized into polyvinyl chloride.

(r) Reactor opening loss means the emissions of vinyl chloride occurring when a reactor is vented to the atmosphere for any purpose other than an emergency relief discharge as defined in § 61.65(a).

(s) Stripper includes any vessel in which residual vinyl chloride is removed from polyvinyl chloride resin, except bulk resin, in the slurry form by the use of heat and/or vacuum. In the case of bulk resin, stripper includes any vessel which is used to remove residual vinyl chloride from polyvinyl chloride resin immediately following the polymerization step in the plant process flow.

(t) Standard temperature means a temperature of 20 °C (69 °F).

(u) Standard pressure means a pressure of 760 mm of Hg (29.92 in. of Hg).

(v) Relief valve means each pressure relief device including pressure relief valves, rupture disks and other pressure relief systems used to protect process components from overpressure conditions. “Relief valve” does not include polymerization shortstop systems, referigerated water systems or control valves or other devices used to control flow to an incinerator or other air pollution control device.

(w) 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.