AF Form 1688: Annual Cathodic Protection Survey (NOT LRA)

AF Form 1688: Annual Cathodic Protection Survey (NOT LRA) – AF Form 1688: Annual Cathodic Protection Performance Survey (NOT LRA) is a key U.S. Air Force document used to record and evaluate the performance of impressed current cathodic protection (CP) systems, specifically focusing on the annual impressed current anode bed survey.

This form helps ensure buried metallic structures—such as pipelines, storage tanks, and utility systems—remain protected against corrosion through effective cathodic protection.

What Is Cathodic Protection and Why Does the Air Force Require It?

Cathodic protection is an electrochemical technique that prevents corrosion of buried or submerged metal structures by making them the cathode in an electrochemical cell. It typically uses either sacrificial (galvanic) anodes or impressed current systems (which employ rectifiers and anode beds to deliver protective current).

The U.S. Air Force mandates cathodic protection for many underground ferrous metallic structures as part of its infrastructure corrosion control program. This requirement appears in guidance such as DAFI 32-1001 (Civil Engineer Operations), older AFI 32-1054 (Corrosion Control), and the tri-service Unified Facilities Criteria (UFC) documents like UFM 3-570-06 / UFC 3-570-06 (Operation and Maintenance: Cathodic Protection Systems).

Corrosion costs the Department of Defense billions annually in repairs, replacements, and downtime. Effective CP programs extend asset life, enhance safety, reduce leaks, and support mission readiness on Air Force installations.

“NOT LRA” stands for “Not Locally Reproducible Authorized.” This means the form is an official, controlled document that must be obtained from authorized Air Force e-Publishing sources rather than photocopied or locally reproduced. The current official version is available as a PDF download from the Air Force e-Publishing site: https://static.e-publishing.af.mil/production/1/af_a4/form/af1688/af1688.pdf.

Purpose of AF Form 1688

The primary purpose of AF Form 1688 is to document the annual impressed current anode bed survey. This survey assesses the condition and performance of the anode bed in an impressed current CP system.

Key objectives include:

  • Verifying that anodes are delivering protective current effectively.
  • Measuring structure-to-soil potentials and other electrical parameters to confirm adequate protection levels (typically aiming for criteria such as -0.85 volts or more negative relative to a copper/copper sulfate reference electrode, per industry and DoD standards).
  • Identifying degradation, failures, or the need for maintenance/repairs in the anode bed.
  • Supporting overall compliance with corrosion control requirements and contributing to the annual cathodic protection performance booklet/report submitted to higher headquarters.

This form complements other CP-related Air Force forms, such as:

  • AF Form 1686: Cathodic Protection Operating Log for Sacrificial Anode System (NOT LRA).
  • AF Form 1687: Leak/Failure Data Record (used for resource advocacy and corrosion control metrics).
  • AF Form 491: Cathodic Protection Operating Log for Impressed Current Systems.

When and How Is AF Form 1688 Used?

According to Air Force guidance:

  • The impressed current anode bed survey must be performed annually.
  • It is documented directly on AF Form 1688.
  • Related activities include close-interval surveys (every 5 years on cathodically protected pipelines) and more frequent impressed current system checks (e.g., within 60 days of prior surveys).
  • Data from the form contributes to the base’s annual CP performance booklet, which is typically provided to higher headquarters around early February each year.

Qualified personnel—often certified cathodic protection technicians or corrosion control specialists—conduct the survey using proper equipment (e.g., voltmeters, reference electrodes) and follow standardized test procedures outlined in UFC 3-570-06 and related technical manuals.

The survey typically involves:

  • Measuring potentials over the anode bed.
  • Checking for uniform current distribution.
  • Recording rectifier outputs, voltage drops, and other parameters.
  • Noting any anomalies that could indicate failing anodes, coating damage, or interference issues.

Results help determine if the system meets protection criteria, supports leak prevention, and informs repair or replacement decisions.

Key Sections and Information Captured on AF Form 1688

While the exact layout is best viewed in the official PDF, the form generally captures:

  • Installation or system identification details (location, asset protected, date of survey).
  • Electrical measurements (structure-to-soil potentials, anode bed potentials, rectifier data).
  • Test results and observations from the anode bed survey.
  • Remarks on system performance, deficiencies, and recommended actions.
  • Signatures of the technician performing the survey and the reviewer/supervisor.

Completed forms are maintained as part of the cathodic protection system records for the installation. They support compliance audits, performance reporting, and long-term asset management.

AF Form 1688 fits into a broader program that includes:

  • Use of protective coatings in combination with CP.
  • Regular monitoring and recordkeeping.
  • Training for personnel involved in CP testing and maintenance.
  • Integration with infrastructure asset management plans (e.g., electrical sub-AMP responsibilities in DAFI 32-1001).

DoD and Air Force policy emphasize corrosion prevention to comply with standards like 10 USC 2228 (Office of Corrosion Policy and Oversight) and DoDI 5000.67.

For detailed testing procedures, refer to current editions of UFC 3-570-06 (updated as of 2026) and associated Air Force handbooks or technical orders.

How to Obtain and Use AF Form 1688?

  1. Download the official form from the provided link on the Air Force e-Publishing website.
  2. Ensure personnel are properly trained and certified (NACE/AMPP cathodic protection certifications are often referenced in DoD guidance).
  3. Perform the annual survey following approved procedures.
  4. Maintain records and incorporate findings into the installation’s corrosion control and asset management programs.
  5. Report significant issues via AF Form 1687 or through the appropriate civil engineer channels.

Note: Always verify the latest version and prescribing instructions on e-Publishing.af.mil, as forms and instructions can be updated. Local base operating instructions or performance work statements may provide additional site-specific guidance.

Why Proper Completion Matters?

Accurate use of AF Form 1688 helps:

  • Prevent costly infrastructure failures and leaks.
  • Demonstrate compliance during inspections and audits.
  • Support funding requests for corrosion-related repairs through metrics like those tracked on AF Form 1687.
  • Extend the service life of critical utility systems on U.S. Air Force installations.

For contractors supporting Air Force bases, understanding and properly documenting CP surveys on official forms is often a contract performance requirement in base operating support (BOS) or civil engineer service contracts.

If you need assistance with cathodic protection system design, testing protocols, or interpreting results, consult a qualified corrosion expert or refer to the latest UFC 3-570-06 and DAFI 32-1001.

Download AF Form 1688 here: https://static.e-publishing.af.mil/production/1/af_a4/form/af1688/af1688.pdf

For the most current Air Force policy on infrastructure corrosion control, review DAFI 32-1001 and related Unified Facilities Criteria on the WBDG (Whole Building Design Guide) website.

This article provides general guidance based on publicly available official sources as of 2026. Always consult the prescribing directive and qualified personnel for specific implementation on your installation.