---
kind: "section"
citation: "40 C.F.R. § 63.168"
title: "40"
number: "63.168"
heading: "Standards: Valves in gas/vapor service and in light liquid service."
url: "https://uscodex.org/cfr/40/63.168"
---

# §63.168. Standards: Valves in gas/vapor service and in light liquid service.

- (a) The provisions of this section apply to valves that are either in gas service or in light liquid service.
  - (1) The provisions are to be implemented on the dates set forth in the specific subpart in [40 CFR part 63](/cfr/40/part63.md) that references this subpart as specified in paragraph [(a)(1)(i)](#a-1-i), [(a)(1)(ii)](#a-1-ii), or [(a)(1)(iii)](#a-1-iii) of this section.
    - (i) For each group of existing process units at existing sources subject to the provisions of subpart F or I of this part, the phases of the standard are:
      - (A) Phase I, beginning on the compliance date;
      - (B) Phase II, beginning no later than 1 year after the compliance date; and
      - (C) **Phase III, beginning no later than 2 1/2 years after the compliance date.**
    - (ii) For new sources subject to the provisions of subpart F or I of this part, the applicable phases of the standard are:
      - (A) After initial start-up, comply with the Phase II requirements; and
      - (B) **Beginning no later than 1 year after initial start-up, comply with the Phase III requirements.**
    - (iii) Sources subject to other subparts in [40 CFR part 63](/cfr/40/part63.md) that reference this subpart shall comply on the dates specified in the applicable subpart.
  - (2) The owner or operator of a source subject to this subpart may elect to meet the requirements of a later phase during the time period specified for an earlier phase.
  - (3) The use of monitoring data generated before April 22, 1994 to qualify for less frequent monitoring is governed by the provisions of [§ 63.180(b)(6)](/cfr/40/63.180.md?p=b-6) of this subpart.
- (b) The owner or operator of a source subject to this subpart shall monitor all valves, except as provided in [§ 63.162(b)](/cfr/40/63.162.md?p=b) of this subpart and paragraphs [(h)](#h) and [(i)](#i) of this section, at the intervals specified in paragraphs [(c)](#c) and [(d)](#d) of this section and shall comply with all other provisions of this section, except as provided in [§ 63.171](/cfr/40/63.171.md), [§ 63.177](/cfr/40/63.177.md), [§ 63.178](/cfr/40/63.178.md), and [§ 63.179](/cfr/40/63.179.md) of this subpart.
  - (1) The valves shall be monitored to detect leaks by the method specified in [§ 63.180(b)](/cfr/40/63.180.md?p=b) of this subpart.
  - (2) Except as specified in [paragraph (b)(2)(iv)](#b-2-iv) of this section, the instrument reading that defines a leak in each phase of the standard is:
    - (i) **For Phase I, an instrument reading of 10,000 parts per million or greater.**
    - (ii) **For Phase II, an instrument reading of 500 parts per million or greater.**
    - (iii) **For Phase III, an instrument reading of 500 parts per million or greater.**
    - (iv) For each source as defined in [§ 63.101](/cfr/40/63.101.md), and for each source as defined in [§ 63.191](/cfr/40/63.191.md), beginning no later than the compliance dates specified in [§ 63.100(k)(11)](/cfr/40/63.100.md?p=k-11), for valves in ethylene oxide service, as defined in [§ 63.101](/cfr/40/63.101.md), that are either in gas service or in light liquid service the instrument reading that defines a leak is 100 parts per million or greater.
- (c) In Phases I and II, each valve shall be monitored quarterly.
- (d) Except as specified in [paragraph (d)(5)](#d-5) of this section, in Phase III, the owner or
  - (1) At process units with 2 percent or greater leaking valves, calculated according to [paragraph (e)](#e) of this section, the owner or operator shall either:
    - (i) Monitor each valve once per month; or
    - (ii) Within the first year after the onset of Phase III, implement a quality improvement program for valves that complies with the requirements of § [63.175 (d)](/cfr/40/63.175.md?p=d) or [(e)](/cfr/40/63.175.md?p=e) of this subpart and monitor quarterly.
  - (2) At process units with less than 2 percent leaking valves, the owner or operator shall monitor each valve once each quarter, except as provided in paragraphs [(d)(3)](#d-3) and [(d)(4)](#d-4) of this section.
  - (3) At process units with less than 1 percent leaking valves, the owner or operator may elect to monitor each valve once every 2 quarters.
  - (4) At process units with less than 0.5 percent leaking valves, the owner or operator may elect to monitor each valve once every 4 quarters.
  - (5) For each source as defined in [§ 63.101](/cfr/40/63.101.md), and for each source as defined in [§ 63.191](/cfr/40/63.191.md), beginning no later than the compliance dates specified in [§ 63.100(k)(11)](/cfr/40/63.100.md?p=k-11), for valves in ethylene oxide service, as defined in [§ 63.101](/cfr/40/63.101.md), that are either in gas service or in light liquid service the monitoring period is once per month.
- (e)
  - (1) Percent leaking valves at a process unit shall be determined by the following equation:
  - (2) For use in determining monitoring frequency, as specified in [paragraph (d)](#d) of this section, the percent leaking valves shall be calculated as a rolling average of two consecutive monitoring periods for monthly, quarterly, or semiannual monitoring programs; and as an average of any three out of four consecutive monitoring periods for annual monitoring programs.
  - (3)
    - (i) Nonrepairable valves shall be included in the calculation of percent leaking valves the first time the valve is identified as leaking and nonrepairable and as required to comply with [paragraph (e)(3)(ii)](#e-3-ii) of this section. Otherwise, a number of nonrepairable valves (identified and included in the percent leaking calculation in a previous period) up to a maximum of 1 percent of the total number of valves in organic HAP service at a process unit may be excluded from calculation of percent leaking valves for subsequent monitoring periods.
    - (ii) If the number of nonrepairable valves exceeds 1 percent of the total number of valves in organic HAP service at a process unit, the number of nonrepairable valves exceeding 1 percent of the total number of valves in organic HAP service shall be included in the calculation of percent leaking valves.
- (f)
  - (1) When a leak is detected, it shall be repaired as soon as practicable, but no later than 15 calendar days after the leak is detected, except as provided in [§ 63.171](/cfr/40/63.171.md) of this subpart.
  - (2) A first attempt at repair shall be made no later than 5 calendar days after each leak is detected.
  - (3) When a leak has been repaired, the valve shall be monitored at least once within the first 3 months after its repair.
    - (i) The monitoring shall be conducted as specified in § [63.180 (b)](/cfr/40/63.180.md?p=b) and [(c)](/cfr/40/63.180.md?p=c), as appropriate, to determine whether the valve has resumed leaking.
    - (ii) Periodic monitoring required by [paragraphs (b) through (d)](#b..d) of this section may be used to satisfy the requirements of this [paragraph (f)(3)](#f-3), if the timing of the monitoring period coincides with the time specified in this [paragraph (f)(3)](#f-3). Alternatively, other monitoring may be performed to satisfy the requirements of this [paragraph (f)(3)](#f-3), regardless of whether the timing of the monitoring period for periodic monitoring coincides with the time specified in this [paragraph (f)(3)](#f-3).
    - (iii) If a leak is detected by monitoring that is conducted pursuant to [paragraph (f)(3)](#f-3) of this section, the owner or operator shall follow the provisions of paragraphs [(f)(3)(iii)(A)](#f-3-iii-A) and [(f)(3)(iii)(B)](#f-3-iii-B) of this section, to determine whether that valve must be counted as a leaking valve for purposes of [§ 63.168(e)](#e) of this subpart.
      - (A) If the owner or operator elected to use periodic monitoring required by [paragraphs (b) through (d)](#b..d) of this section to satisfy the requirements of [paragraph (f)(3)](#f-3) of this section, then the valve shall be counted as a leaking valve.
      - (B) If the owner or operator elected to use other monitoring, prior to the periodic monitoring required by [paragraphs (b) through (d)](#b..d) of this section, to satisfy the requirements of [paragraph (f)(3)](#f-3) of this section, then the valve shall be counted as a leaking valve unless it is repaired and shown by periodic monitoring not to be leaking.
- (g) **First attempts at repair include, but are not limited to, the following practices where practicable—**
  - (1) Tightening of bonnet bolts,
  - (2) Replacement of bonnet bolts,
  - (3) Tightening of packing gland nuts, and
  - (4) **Injection of lubricant into lubricated packing.**
- (h) Any valve that is designated, as described in [§ 63.181(b)(7)(i)](/cfr/40/63.181.md?p=b-7-i) of this subpart, as an unsafe-to-monitor valve is exempt from the requirements of [paragraphs (b) through (f)](#b..f) of this section if:
  - (1) The owner or operator of the valve determines that the valve is unsafe to monitor because monitoring personnel would be exposed to an immediate danger as a consequence of complying with [paragraphs (b) through (d)](#b..d) of this section; and
  - (2) The owner or operator of the valve has a written plan that requires monitoring of the valve as frequently as practicable during safe-to-monitor times, but not more frequently than the periodic monitoring schedule otherwise applicable.
- (i) Any valve that is designated, as described in [§ 63.181(b)(7)(ii)](/cfr/40/63.181.md?p=b-7-ii) of this subpart, as a difficult-to-monitor valve is exempt from the requirements of [paragraphs (b) through (d)](#b..d) of this section if:
  - (1) The owner or operator of the valve determines that the valve cannot be monitored without elevating the monitoring personnel more than 2 meters above a support surface or it is not accessible at anytime in a safe manner;
  - (2) The process unit within which the valve is located is an existing source or the owner or operator designates less than 3 percent of the total number of valves in a new source as difficult-to-monitor; and
  - (3) The owner or operator of the valve follows a written plan that requires monitoring of the valve at least once per calendar year.
- (j) Any equipment located at a plant site with fewer than 250 valves in organic HAP service is exempt from the requirements for monthly monitoring and a quality improvement program specified in [paragraph (d)(1)](#d-1) of this section. Instead, the owner or operator shall monitor each valve in organic HAP service for leaks once each quarter, or comply with paragraph [(d)(3)](#d-3) or [(d)(4)](#d-4) of this section except as provided in paragraphs [(h)](#h) and [(i)](#i) of this section.

## Notes

### Amendments

[59 FR 19568, Apr. 22, 1994, as amended at 59 FR 48176, Sept. 20, 1994; 61 FR 31440, June 20, 1996; 62 FR 2790, Jan. 17, 1997; 89 FR 43223, May 16, 2024]

### Source

Source: 59 FR 19568, Apr. 22, 1994, unless otherwise noted.

### Authority

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

### Source

Source: 57 FR 61992, Dec. 29, 1992, unless otherwise noted.

### Amendments

[59 FR 19568, Apr. 22, 1994, as amended at 59 FR 48176, Sept. 20, 1994; 61 FR 31440, June 20, 1996; 62 FR 2790, Jan. 17, 1997; 89 FR 43223, May 16, 2024]