Special Topics in Environmental Management

SPCC Diagrams and Descriptions – The Devil is in the Details

Federal SPCC regulations provide required aspects of diagrams and descriptions, but the EPA also makes many recommendations that warrant attention. Although not abiding by these recommendations cannot necessarily result in a violation, inspectors may appreciate the extra effort that goes into including recommended aspects as well as the additional information provided.

One set of recommendations applies to facility diagrams and is intended to increase the diagram’s value for facility personnel, emergency responders and inspectors. These include:

  • Aboveground storage tank capacities and/or Identification numbers or letters,
  • Secondary containment structures ( including oil/water separators used for containment)
  • Direction of flow in the event of a discharge (also addresses requirements under Section 112.7 (b)),
  • A legend providing scale and any symbols used in the diagram,
  • Compass direction indicating north,
  • Location of spill response kits/equipment,
  • Location of firefighting equipment and pipe stands for foam,
  • Location of valves or drainage system controls,
  • Location of important piping appurtenances including valves, checks, etc.,
  • Location and contents of containers storing Clean Water Act (CWA) hazardous substances, and
  • Topographical information and area maps.

Learn a brief review of the SPCC regulations and the recent amendment process and much more during our in-depth webinar on February 13, 2014.
Register Now


Should a facility have intricate equipment that is covered under the SPCC rule, EPA recommends locating the equipment on the diagram but providing detailed system diagrams separately, with location of the separate diagrams referenced in the SPCC Plan. Similarly, if a diagram will become complicated  because of too many containers or equipment in a small space, tables maybe be used to provide the required information in reference to the diagram.

Mobile or portable containers are not specifically defined in the SPCC rule but EPA recommends they may include 55-galoon drums, skid tanks, totes, intermediate bulk containers (IBCs), and other small containers put in place and later moved. When such containers are stored in one area and used in another area both areas should be identified on the diagram. EPA also notes that contents of these containers must be provided, and when the substances change frequently, the contents may be recorded separately in a log or electronic system, although the diagram should confirm that the contents vary.

With regard to underground storage tanks (USTs),  a facility diagram must include all USTs, those that are covered by the SPCC rule and those that are exempt (which should be marked as such). In the same way, transfer station intra-facility gathering lines that are exempted under 112.7 (a)(3) must also be identified on the diagram and marked as “exempt.”


Join us for an in-depth webinar on February 13 . Our speaker, a seasoned environmental professional who has helped many companies assure SPCC plan compliance, will provide you with a proven, straightforward process for evaluating existing SPCC plans, identifying potential gaps, and developing the necessary corrective action strategies.


Facilities that have oil-filled equipment and associated piping covered under the SPCC rule are allowed flexibility and may provide a less detailed representation on the diagram while maintaining more detailed drawings on-site and referencing them and their location in the SPCC Plan. Such additional drawings might include blueprints, engineering diagrams or diagrams developed for compliance with other regulatory requirements.

It is especially important to remember that even when a SPCC Plan and diagram are certified either by the owner/operator or a licensed Professional Engineer (PE), as applicable, any facility changes that occur may require changes to both the plan and the diagram to remain in compliance. However, changes to a facility diagram are considered administrative and  not technical amendments and as such  do not require PE recertification, even for Tier II facilities.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.