---
kind: "section"
citation: "33 C.F.R. § 154.2109"
title: "33"
number: "154.2109"
heading: "Vapor recovery and vapor destruction units."
url: "https://uscodex.org/cfr/33/154.2109"
---

# §154.2109. Vapor recovery and vapor destruction units.


Paragraphs [(a)](#a), [(b)](#b), and [(e)](#e) of this section apply only to facilities collecting vapors of flammable, combustible, or non-high flash point liquid cargoes.

- (a) The inlet to a vapor recovery unit that receives vapor that has not been inerted, enriched, or diluted in accordance with [33 CFR 154.2107](/cfr/33/154.2107.md) must be fitted with a detonation arrester.
- (b) **The inlet to a vapor destruction unit must—**
  - (1) Have a liquid seal that meets the requirements of [paragraph (e)](#e) of this section, except as specified by [paragraph (b)(3)](#b-3) of this section; and
  - (2) **Have two quick-closing stop valves installed in the vapor line.** One of them must be installed upstream of the detonation arrester required by [paragraph (c)(2)](#c-2) of this section. The quick-closing stop valves must—
    - (i) Close within 30 seconds after detection of a condition that requires the closing of these two quick-closing stop valves by a control component required by this subpart for a vapor control system (VCS) with a vapor destruction unit;
    - (ii) Close automatically if the control signal is lost;
    - (iii) Have a local valve position indicator or be designed so that the valve position is readily determined from the valve handle or valve stem position; and
    - (iv) If the valve seat is fitted with resilient material, be a Category A valve as defined by [46 CFR 56.20-15](/cfr/46/56.20-15.md) and not allow appreciable leakage when the resilient material is damaged or destroyed; and
  - (3) **Instead of a liquid seal as required by paragraph (b)(1) of this section, have the following—**
    - (i) An anti-flashback burner accepted by the Commandant and installed at each burner within the vapor destruction unit; and
    - (ii) A differential pressure sensor that activates the quick-closing stop valves as required by [paragraph (b)(2)](#b-2) of this section upon sensing a reverse flow condition.
- (c) **A vapor destruction unit must—**
  - (1) Not be within 30 meters (98.8 feet) of any tank vessel berth or mooring at the facility;
  - (2) Have a detonation arrester fitted in the inlet vapor line; and
  - (3) Activate an alarm that satisfies the requirements of [33 CFR 154.2100(e)](/cfr/33/154.2100.md?p=e) and shut down when a flame is detected on the detonation arrester.
- (d) When a vapor destruction unit shuts down or has a flame-out condition, the vapor destruction unit control system must—
  - (1) Activate and close the quick-closing stop valves required by [paragraph (b)(2)](#b-2) of this section;
  - (2) Close the remotely operated cargo vapor shutoff valve required by [33 CFR 154.2101(a)](/cfr/33/154.2101.md?p=a); and
  - (3) **Automatically shut down any vapor-moving devices installed in the VCS.**
- (e) If a liquid seal is installed at the inlet to a vapor destruction unit, then—
  - (1) The liquid used in the liquid seal must be compatible with the vapors being controlled;
  - (2) For partially or totally soluble cargoes that can polymerize in solution, there must be an adequate amount of inhibitor in the liquid seal;
  - (3) The liquid seal must be compatible with the design of the VCS and must not contribute to the flammability of the vapor stream; and
  - (4) The liquid seal must have a low-level alarm and a low-low level shutdown.

## Notes

### Source

Source: USCG-1999-5150, 78 FR 42618, July 16, 2013, unless otherwise noted.

### Authority

Authority: 33 U.S.C. 1321(j)(1)(C), (j)(5), (j)(6), and (m)(2); 46 U.S.C. 70011, 70034; sec. 2, E.O. 12777, 56 FR 54757; Department of Homeland Security Delegation No. 00170.1, Revision No. 01.2. Subpart F is also issued under 33 U.S.C. 2735. Vapor control recovery provisions of Subpart P are also issued under 42 U.S.C. 7511b(f)(2).