---
kind: "section"
citation: "40 C.F.R. § 65.85"
title: "40"
number: "65.85"
heading: "Procedures."
url: "https://uscodex.org/cfr/40/65.85"
---

# §65.85. Procedures.

- (a) **Vapor tightness.** For the purposes of demonstrating vapor tightness to determine compliance with [§ 65.84(c)(2)](/cfr/40/65.84.md?p=c-2), the following procedures and equipment shall be used:
  - (1) The pressure test procedures specified in Method 27 of appendix A of [40 CFR part 60](/cfr/40/part60.md); and
  - (2) A pressure measurement device that has a precision of ±2.5 millimeters of mercury (0.10 inch) or better and that is capable of measuring above the pressure at which the tank truck or railcar is to be tested for vapor tightness.
- (b) **Engineering assessment.** Engineering assessment to determine if a vent stream is halogenated or flow rate of a gas stream includes, but is not limited to, the following examples:
  - (1) Previous test results, provided the tests are representative of current operating practices at the process unit.
  - (2) Bench-scale or pilot-scale test data representative of the process under representative operating conditions.
  - (3) Maximum flow rate or halogen emission rate specified or implied within a permit limit applicable to the process vent.
  - (4) Design analysis based on accepted chemical engineering principles, measurable process parameters, or physical or chemical laws or properties.
  - (5) All data, assumptions, and procedures used in the engineering assessment shall be documented.
- (c) **Halogenated vent stream determination.** In order to determine whether a vent stream is halogenated, the mass emission rate of halogen atoms contained in organic compounds shall be calculated as specified in paragraphs [(c)(1)](#c-1) and [(2)](#c-2) of this section.
  - (1) The vent stream concentration of each organic compound containing halogen atoms (parts per million by volume by compound) shall be determined based on any of the following procedures:
    - (i) Process knowledge that no halogen or hydrogen halides are present in the vent stream; or
    - (ii) Applicable engineering assessment as specified in [paragraph (b)](#b) of this section; or
    - (iii) Concentration of organic compounds containing halogens measured by Method 18 of appendix A of [40 CFR part 60](/cfr/40/part60.md); or
    - (iv) Any other method or data that have been validated according to the applicable procedures in Method 301 of appendix A of [40 CFR part 63](/cfr/40/part63.md).
  - (2) Equation 85-1 of this section shall be used to calculate the mass emission rate of halogen atoms:

## Notes

### Authority

Authority: 42 U.S.C. 7401 et seq.

### Source

Source: 65 FR 78285, Dec. 14, 2000, unless otherwise noted.