Concerned About EPA’s New Kc Standards?

Recently the United States Environmental Protection Agency (EPA), has proposed a revision to 40 CFR 60, known as subpart Kc.  This is the first revision of this standard since the 1980’s!  The revision has passed through public comment, and we await the final version due out in September of 2024.

So what does this all mean?

What is 40 CFR 60 Subpart K(b or c)?

This specific section of the standard focuses on above ground storage tanks that store volatile organic liquids (VOL).  In general, the standard indicates when it should be applied such as storage volume, true vapor pressure (a measure of volatility), and features of the tank, to name a few.

In reference to volatility, the standards discuss pressures ranging from 0.5 psia to over 11.1 psia.  In general, this covers products like ethanol, jet fuel, crude oil, and gasoline, but not products like diesel or fuel oil.

What does 40 CFR 60 Subpart K(b or c) dictate?

The standard focuses on emissions control devices like rim seals as well as other means for controlling emissions.  This standard provides guidance for some dimensional requirements of rim seals including the frequency and method of performing and qualifying gap measurements.  A large portion of the standard covers recordkeeping practices as well.

What is proposed to change between Kb and Kc?

Categories describing the changes can be boiled down to emissions control equipment, vapor capture, degassing, and monitoring.  Kc introduces targeted emission control efficiency of 98% compared to 95% in Kb, which prompts several changes.  Importantly, there is a path to 98% efficiency for both internal and external floating roof tanks.  The following changes relate to emissions control for tanks storing liquids with true vapor pressure less than 11.1 psia:

Internal floating roofs (tanks with a cone or dome):

Seals: Primary must be liquid mounted or mechanical shoe with a rim mounted secondary.

Guide poles/ladders: Various requirements including gauge pole and ladder pole covers

External floating roofs (tanks without a cone or dome):

Seals: Primary liquid mounted seal only with rim mounted secondary if there is a slotted guide pole with various sealing requirements.  Mechanical shoe seal with rim mounted secondary if there is an unslotted guide pole.

When does Kc go into effect?

Anticipated September 2024.

When does Kc apply?

New construction, rebuilt, or modification, including storage of an increased vapor pressure VOL. 

Does the standard push owners to internal floating roof tanks?

No, the standard offers a path to 98% emissions efficiency with internal and external floating roof tanks.  Notable is the requirement of a liquid mounted primary seal for external tanks with the extremely common slotted gauge pole.  No need to worry, there is new technology available, FlexCore^TM with Armor Fabric^TM, that can ease your worries and offer you mechanical shoe seal life with the benefits of the superior emission control of a liquid mounted seal.  You can build your EFR with our help!

How can Mesa ETP help?

Mesa’s sales managers and engineers can help you navigate this new standard.  Mesa can provide all emissions control devices necessary to comply.  Mesa has the only durable liquid mounted seal available, FlexCore with Armor Fabric abrasion proof barrier.  Our liquid mounted seal has the longevity of a mechanical shoe seal, so you can be confident knowing the seal will perform effectively throughout the maintenance lifecycle.

Want to learn more?

This summary only offers highlights.  You can find a link to the proposed change here: EPA’s new Kc standards.

Still more questions? 

Reach out to Mesa ETP, your experts in navigating through Kc implementation.