EPA Redefines “Pneumatic Controllers” as “Process Controllers”

The US Environmental Protection Agency (EPA) recently adopted a new definition of “pneumatic controllers,” now called “process controllers,” under New Source Performance Standards (NSPS) OOOOb that encompasses controllers previously excluded from the regulation. This Delve explores the new definition and its implications for affected facilities. 

Process Controllers: New Name and Definition 

NSPS OOOOb redefines process controllers as “automated instruments used to maintain a process condition, such as liquid level, pressure, pressure differential, or temperature.” The EPA also clarifies that process controllers not powered by natural gas are not considered part of affected facilities and will not be included in determining whether a modification or reconstruction has occurred. Notably, the revised definition now encompasses devices such as back pressure controllers, which were previously excluded. 

The affected components include any new, modified, or reconstructed natural gas-driven process controllers at a site (e.g. well site, centralized production facility, onshore natural gas processing plant, or compressor station). Emergency shutdown device and non-natural gas-driven process controllers are not included in the affected facility.  

Modification is considered to have occurred when one or more natural gas-driven process controllers are added to the affected facility. 

Reconstruction is considered to have occurred when more than 50% of natural gas-driven process controllers at a site are replaced within any 24-month rolling period starting December 6, 2022 (including continuous replacement programs). It also occurs if the fixed capital cost of new process controllers exceeds 50% of the cost required to replace all natural gas-driven controllers in the affected facility within any 24-month rolling period after December 6, 2022. 

Compliance Deadlines 

To accommodate the time needed for new sources to acquire the necessary equipment to meet the zero-emissions standard, EPA has established a compliance deadline of up to one year from the effective date of the final rule. This means that new sources must demonstrate compliance with the zero-emissions requirement by May 7, 2025. Each process controller must either: 

• Be routed to a process through a closed vent system (CVS)
  • Route vent gas to a process or a control device such as flare, combustor, or vapor recovery unit
• Be self-contained with no identifiable emissions (NIE)
  • Use manufacturer no-vent retrofit kits
  • Switch actuation gas to instrument air or supplied nitrogen
  • Use electric-driven controllers 

Monitoring Requirements for Process Controllers 

Recordkeeping and Reporting Requirements 

• Notification requirements
  • When a reconstruction occurs, follow required agency notification requirements pursuant to §60.15(a).
• Report submission deadline
  • Due 90 days after the initial compliance period or no later than August 5, 2025.
• Required information in the report
  • Identification of each natural gas-driven pneumatic device
    • Specify which devices are routed to a process/CVS and include dates and results of inspections conducted.
    • Specify which devices are self-contained with NIE and include dates and results of inspections conducted.
  • Identification of each natural gas-driven controller in the affected facility
    • Excludes emergency shutdown devices.
  • Deviation reporting
    • Document any deviations from process controller emissions standards during the reporting period.

While not explicitly required, maintaining a tagged inventory is a recommended best practice for operators. It can help track monitoring requirements, determine modification applicability, and facilitate emissions reporting under Subpart W. Additionally, a tagged inventory allows operators to identify repeat malfunctioning devices for proactive maintenance and better budget for future equipment needs.