PRESSURE RELIEF DEVICE LANGUAGE IN AMF_PC_P&R III RULE

8. Pressure Relief Devices

For the AMF, PC and APR MACT standards, we are proposing, as part of our revisions to address

periods of SSM in response to the 2008 Sierra Club ruling, to specify that PRD in organic HAP 

service may not release to the atmosphere. To ensure compliance with this requirement, we 

are further proposing to require facility owners or operators in these three source categories to 

employ monitoring capable of (1) immediately alerting an operator when there is an 

atmospheric release from a PRD in organic HAP service and (2) recording the time and duration 

of each pressure release. Owners or operators would be required to report any pressure 

release and an estimate of the amount of organic HAP released to the atmosphere with the 

next periodic report.

We believe that PRD releases that are vented directly to the atmosphere are caused by

malfunctions. Emissions vented to the atmosphere by PRDs may contain HAP that are 

otherwise regulated under the MACT standards. In Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 

2008), the court determined that standards under CAA section 112(d) must provide for 

compliance at all times. Therefore, the proposed rule revisions provide that a pressure release 

from a PRD in organic HAP service, unless routed to a control device or process, is a violation of 

the emission standard. As with any malfunction event, an owner or operator may assert an 

affirmative defense against civil penalties for a malfunction causing a pressure release from a

PRD in organic HAP service to the atmosphere.

Pressure release events from PRDs in organic HAP service to the atmosphere have the potential 

to emit large quantities of HAP. Where a release occurs, it is important to identify and mitigate 

it as quickly as possible. Therefore, we are proposing to require that sources monitor PRDs in

organic HAP service using a device or system that is capable of identifying and recording the 

time and duration of each pressure release and of notifying operators that a release has 

occurred. For purposes of estimating the costs of this requirement, we assumed that operators 

would install electronic indicators on each PRD in organic HAP service that vents to the 

atmosphere to identify and record the time and duration of each pressure release. However,

owners or operators could use a range of methods to satisfy these requirements, including the 

use of a parameter monitoring system that may already have been in place on the process

operating pressure that is sufficient to notify operators immediately that a pressure release is 

occurring, as well as recording the time and duration of that release.

Based on our cost assumptions that the most expensive approach would be used, the 

nationwide capital cost of installing these monitors is $37,000, $400,000 and $51,000 for the 

AMF, APR and PC source categories, respectively. The total annualized cost of installing and 

operating these monitors is $5,300, $56,000 and $7,200 per year for the AMF, APR and PC

source categories, respectively.
3. Section 63.1101 is amended by adding in alphabetical order the terms “Affirmative defense,” 

“Pressure release,” and “Pressure relief device or valve” to read as follows:

§ 63.1101 Definitions.

Pressure release means the emission of materials resulting from the system pressure being 

greater than the set pressure of the pressure relief device. This release can be one release or a

series of releases over a short time period due to a malfunction in the process.

Pressure relief device or valve means a safety device used to prevent operating pressures from

exceeding the maximum allowable working pressure of the process equipment. A common

pressure relief device is a spring-loaded pressure relief valve.

Devices that are actuated either by a pressure of less than or equal to 2.5 pounds per square 

inch gauge or by a vacuum are not pressure relief devices.

§ 63.1102 Compliance schedule.

(b) All acrylic and modacrylic fiber production affected sources and polycarbonate production 

affected sources that commenced construction or reconstruction on or before [INSERT DATE 

OF PUBLICATION IN THE FEDERAL REGISTER], shall be in compliance with the pressure relief 

device monitoring requirements of § 63.1107(e)(3) upon initial startup or 3 years after the 

effective date of the final amendments, whichever is later, and the equipment leaks 

requirements of 40 CFR part 63, subpart UU upon initial startup or 1 year after the effective

date of the final amendments, whichever is later. New acrylic and modacrylic fiber production 

affected sources and polycarbonate production affected sources that commence construction 

or reconstruction after [INSERT DATE OF PUBLICATION IN FEDERAL REGISTER], shall be in 

compliance with the pressure relief device monitoring requirements of § 63.1107(e)(3) upon

initial startup or by the effective date of the final amendments, whichever is later.

* * * * *

§ 63.1107 Equipment leaks.

* * * * *

(e) Requirements for pressure relief devices. For acrylicand modacrylic fiber production 

affected sources and polycarbonate production affected sources, except as specified in 

paragraph (e)(4) of this section, the owner or operator must comply with the requirements 

specified in paragraphs (e)(1) and (2) of this section for pressure relief devices in organic HAP

gas or vapor service. Except as specified in paragraph (e)(4) of this section, the owner or 

operator of an acrylic and modacrylic fiber production affected source or polycarbonate 

production affected source must also comply with the requirements specified in paragraph 

(e)(3) of this section for all pressure relief devices in organic HAP service.

(1) Operating requirements. Except during a pressure release event, operate each 

pressure relief device in organic HAP gas or vapor service with an instrument reading of 

less than 500 ppm above background as detected by Method 21 of 40 CFR part 60, 

appendix A.

(2) Pressure release requirements. For pressure relief devices in organic HAP gas or 

vapor service, comply with paragraph (e)(2)(i) or (ii) of this section, as applicable.
(i) If the pressure relief device does not consist of or include a rupture disk, 

conduct instrument monitoring, as detected by Method 21 of 40 CFR part 60, 

appendix A, no later than 5 calendar days after the pressure relief device returns 

to organic HAP service following a pressure release to verify that the pressure 

relief device is operating with an instrument reading of less than 500 ppm above 

background. After 5 calendar days, an instrument reading of 500 ppm above 

background or greater is a violation.

(ii) If the pressure relief device consists of or includes a rupture disk, install a 

replacement disk as soon as practicable after a pressure release, but no later 

than 5 calendar days after the pressure release. The owner or operator must also 

conduct instrument monitoring, as detected by Method 21 of 40 CFR part 60, 

appendix A, no later than 5 calendar days after the pressure relief device returns 

to organic HAP service following a pressure release to verify that the pressure 

relief device is operating with an instrument reading of less than 500 ppm above 

background. After 5 calendar days, an instrument reading of 500 ppm above 

background or greater is a violation.

(3) Pressure release management. Except as specified in paragraph (e)(4) of this section, 

the owner or operator must comply with the requirements specified in paragraphs 

(e)(3)(i) and (ii) of this section for all pressure relief devices in organic HAP service. Any 

pressure release from such a pressure relief device is a violation.

(i) The owner or operator must equip each pressure relief device in organic HAP 

service with a device(s) or parameter monitoring system that is capable of 

identifying and recording the time and duration of each pressure release and of 

notifying operators immediately that a pressure release is occurring. Examples of 

these types of devices and systems include, but are not limited to, a rupture disk 

indicator, magnetic sensor, motion detector on the pressure relief valve stem, 

flow monitor, or pressure monitor. Regardless of the methodology chosen, when

the device or monitoring system indicates that a pressure release has occurred, 

it shall be directly enforceable as a release from the pressure relief device. If this 

instrument is capable of measuring the concentration of leaks through the

pressure relief device, then the owner or operator may use this instrument to 

meet the requirements of paragraph (e)(2) of this section.

(ii) If any pressure relief device in organic HAP service releases to atmosphere as 

a result of a pressure release event, the owner or operator must calculate the 

quantity of organic HAP released during each pressure release event and report 

this quantity as required in paragraph (g) of this section. Calculations may be 

based on data from the pressure relief device monitoring alone or in 

combination with process parameter monitoring data and process knowledge.

(4) Pressure relief devices routed to a control device or process. If a pressure relief 

device in organic HAP service is designed and operated to route all pressure releases 

through a closed vent system to a control device or process, the owner or operator is 

not required to comply with paragraphs (e)(1), (2), or (3) (if applicable) of this section. 

Both the closed vent system and control device (if applicable) must meet the

requirements of § 63.1034 of this part.
(f) Recordkeeping requirements. For acrylic and modacrylic fiber production affected sources 

and polycarbonate production affected sources, for pressure relief devices in organic HAP

service, keep records of the information specified in paragraphs (f)(1) through (5) of this 

section, as applicable.

(1) A list of identification numbers for pressure relief devices that the owner or operator 

elects to equip with a closed-vent system and control device, under the provisions in

paragraph (e)(4) of this section.

(2) A list of identification numbers for pressure relief devices subject to the provisions in 

paragraph (e)(1) of this section.

(3) A list of identification numbers for pressure relief devices equipped with rupture 

disks, under the provisions in paragraph (e)(2)(ii) of this section.

(4) The dates and results of the monitoring following a pressure release for each 

pressure relief device subject to the provisions in paragraph (e)(1) and (2) of this 

section. The results shall include:

(i) The background level measured during each compliance test.

(ii) The maximum instrument reading measured at each piece of equipment 

during each compliance test.

(5) For pressure relief devices in organic HAP service subject to paragraph (e)(3) of this 

section, keep records of each pressure release to the atmosphere, including the 

following information:

(i) The source, nature, and cause of the pressure release.

(ii) The date, time, and duration of the pressure release.

(iii) An estimate of the quantity of total HAP emitted during the pressure release 

and the calculations used for determining this quantity.

(iv) The actions taken to prevent this pressure release.

(v) The measures adopted to prevent future such pressure releases.

(g) Periodic reports. For owners or operators of an acrylic and modacrylic fiber production

affected source or polycarbonate production affected source subject to paragraph (e) of this

section, Periodic Reports must include the information specified in paragraphs (g)(1) through 

(3) of this section for pressure relief devices in organic HAP service.

(1) For pressure relief devices in organic HAP service subject to paragraph (e) of this 

section, report confirmation that all monitoring to show compliance was conducted 

within the reporting period.

(2) For pressure relief devices in organic HAP gas or vapor service subject to paragraph 

(e)(2) of this section, report any instrument reading of 500 ppm above background or 

greater, more than 5 days after the relief device returns to organic HAP gas or vapor 

service after a pressure release.

(3) For pressure relief devices in organic HAP service subject to paragraph (e)(3) of this 

section, report each pressure release to the atmosphere, including the following

information:

(i) The source, nature, and cause of the pressure release.

(ii) The date, time, and duration of the pressure release.
(iii) An estimate of the quantity of total HAP emitted during the pressure release 

and the method used for determining this quantity.

(iv) The actions taken to prevent this pressure release.

(v) The measures adopted to prevent future such pressure releases.