ISO Corrosivity Category Estimation Tool (ICCET)

The ICCET estimates general atmospheric corrosion severity at a selected location for metals and alloys. It uses a Google Maps interface and National Oceanic and Atmospheric Administration (NOAA) data (ISD-Lite) environmental data to provide an estimated ISO Corrosivity Category for a chosen location. (Note: For DoD Installations, Environmental Severity Classification (ESC) defined in UFC 1-200-01 DoD Building Code takes precedence over this tool).

The ICCET uses three corrosion estimation models that were developed to estimate corrosion mass loss and ISO corrosivity categories. Each model is based on a separate salinity value, a measure of relative distance to saltwater:

• Model 1: less than or equal to 1 mile
• Model 2: greater than one mile but less than or equal to 6 miles
• Model 3: greater than 6 miles

The ISO Corrosivity Classification method is contained in ISO 9223 and defines six corrosivity categories (C1 - very low, C2 - low, C3 - medium, C4 - high, C5 - very high, CX– extreme- offshore environments) based on one-year corrosion mass loss or penetration of steel, zinc, copper, and aluminum coupons.

The ISO Corrosivity Method and Categories was selected for a variety of reasons, including:

• ISO Corrosivity atmospheric exposure data obtained from the ISO International Atmospheric Exposure Program correlates well with DoD one-year corrosion rate data at DoD locations around the world.
• The method integrates well with available environmental data available from NOAA.
• ISO Standards are compliant with DoD policy mandating use of Non-Government Standards pursuant to DoDI 4120.24 Defense Standardization Program and MIL-STD-3007G Standard Practice Unified Facilities Criteria, Facilities Criteria And Unified Facilities Guide Specifications.

Pre-calculated ISO Categories for DoD installations using the ICCET are identified as Environmental Severity Classification (ESC) and can be found in Unified Facilities Criteria (UFC) 1-200-01 DoD Building Code Appendix A. Additional information and requirements for the use of ESC values can be found in Chapter 4-1.2 of the DoD Building Code.

ICCET user guidance:

• Drop a pin on the Google Map interface for the selected location.
• Input a starting year and range (five years is a good start range).
• Select “yes” or “no” depending on if site is within the six-mile limit.
• If “yes”, then measure distance based on Google Map interface and input distance in miles.
• Data completeness (optional, default is 90%). If the location has difficulty in finding data or proximate weather station, then incrementally lower the percentage.
• After all parameters have been entered, select "OK, find station and get values.” The ICCET automatically finds the nearest weather station and evaluates the weather data for completeness within the given data completeness range. If the data is not sufficient, the tool will find the next nearest weather station. Note that the weather station parsing of data is shown in the Log to the left of the Google Map. This could take 3 minutes or longer to find a suitable station and download the data.
• Once a suitable station is identified, the tool identifies the weather station, % completeness of data, the estimated ISO Corrosivity and the estimated steel mass loss.

See the CPC Source–Environmental Severity Classification (ESC) page for an explanation of associated ESC limitations.