Proposed NSPS Kc

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On Wednesday, October 4, 2023, the Federal Register published EPA’s proposed amendments to the New Source Performance Standards for Volatile Organic Liquid Storage Vessels (Including Petroleum Liquid Storage Vessels) as the preliminary results of the review of the New Source Performance Standards (NSPS) required by the Clean Air Act. The EPA is proposing revisions to the NSPS that are applicable to volatile organic liquid (VOL) storage vessels that commence construction, reconstruction, or modification after October 4, 2023 under a new NSPS subpart (Kc).

In the new NSPS subpart, the EPA is proposing:

  • that a change in the liquid stored which results in increased VOC emissions would be a modification under NSPS subpart Kc
  • to reduce the vapor pressure applicability thresholds;
    • max TVP for small storage vessels (20,000-40,000 gallons): 1.5 psia
    • max TVP for larger storage vessels (>40,000 gallons): 0.5 psia
  • to revise the volatile organic compound (VOC) standards to reflect the best system of emissions reductions (BSER) for affected storage vessels;
    • BSER for new or reconstructed IFR tanks used to store liquids with maxi TVP below 11.1 psia (76.6 kPa) is primary seals either liquid-mounted or mechanical shoe seals and a rim-mounted secondary seal
    • BSER for new or reconstructed EFR tanks is primary seals either liquid-mounted or mechanical shoe seals and a rim-mounted secondary seal, welded seams,
      • unslotted guide poles must have gasketed sliding cover and pole wiper 
      • slotted guide poles must have a gasketed sliding cover, pole sleeve and pole wiper (with or without float)
    • BSER for existing EFR tanks that have been modified and used to store liquids with max TVP below 11.1 psia (76.6 kPa) is the EFR requirements as specified in NSPS Kb.
    • BSER for controlled storage vessels that store liquids with a max TVP equal to or greater than 11.1 psia (76.6 kPa) is a closed vent system and a control device meeting a 98% control efficiency
  • to add monitoring and operating requirements to ensure continuous compliance with the standard;
    • add annual monitoring of IFR storage vessels using a LEL monitor to identify floating roofs with poorly functioning seals or fitting controls
    • equipping floating roof storage vessels with a visual or audible alarm system to monitor when the floating roof approaches specified landing heights
    • quarterly visual, audible, and olfactory inspections, annual EPA Method 21 instrument monitoring, and monitoring of bypasses for closed vent systems
    • pressure relief device release detection
    • control device periodic performance testing
  • degassing emission controls; 
    • BSER for tanks with a capacity of 1-million gallon or more storing organic liquids with a maximum true vapor pressure of 1.5 psia or more is a control device utilized to achieve a 98 percent destruction efficiency until the vapor space concentration is within 10 percent of the LEL
  • clarification of startup, shutdown, and malfunction requirements; 
  • requirements for electronic reporting; 
  • other technical improvements; and
  • to amend NSPS subpart Kb to apply to VOL storage vessels that commence construction, reconstruction or modification after July 23, 1984 and on or before October 4, 2023.

Comments must be received on or before November 20, 2023.  

Contact your TRICORD CRM to discuss possible implications and triggers.