Emergency Power Generator UST Systems – 2015 Requirement for Release Detection

In 2015, EPA revised the underground storage tank (UST) regulations.

The 1988 UST regulation required UST systems that store fuel solely for use by emergency power generators to meet all of the regulatory requirements except subpart D – the release detection requirements. The revised UST regulation requires owners and operators of emergency power generator UST systems to meet the release detection requirements in subpart D as follows:

• Emergency generator UST systems installed on or before October 13, 2015 must begin meeting the release detection requirements not later than October 13, 2018.
• Emergency generator UST systems installed after October 13, 2015 must meet release detection requirements when they are installed.

View more information about release detection requirements.

EPA recognizes the optional use of an Automated Interstitial Monitoring (AIM) system as meeting the federal pressurized piping release detection requirements. EPA provided an in-depth technical discussion of these systems and an introduction to owners and operators, respectively, in these two publications:    

• In-Depth Discussion: Automated Interstitial Monitoring Systems for Underground Pressurized Piping on Emergency Power Generator UST Systems (EPA 510-K-22-002). May 2022.
• Owner and Operator Introduction: Automated Interstitial Monitoring Systems for Underground Pressurized Piping on EPG UST Systems (EPA 510-K-22-001). May 2022.

To help owners and operators complete submitting certification of compliance for their AIM systems to their UST implementing agencies and meet periodic inspection and testing requirements, owners and operators may use the interactive PDF forms provided by EPA.  These forms are available through this link:    

• Certification, Inspections and Testing Forms: Automated Interstitial Monitoring Systems for Underground Pressurized Piping on Emergency Power Generator UST Systems. May 2022.

EPA responded to several questions about release detection and general issues pertaining to emergency power generator UST systems.  See the emergency power generator UST systems related questions and answers provided in the UST Technical Compendium about the 2015 Federal UST Regulations.