The EQUILAM NA Cyclic Corrosion Test (C.C.T) Chambers are built with:

• Indirect heating of the test chamber through  hot air space, as illustrated in the diagram below. Therefore, electric heating elements inside the internal test chamber are not allowed.

• Lid with smooth internal finish; no structural elements are allowed on the inner side of the lid. It must have an angle between 90 and 125 degrees. The construction material must be hard enough to resist scratching from salt crystals in order to prevent grooves that could cause dripping onto the specimens, which would increase localized saline concentration and distort test results.

• Atomizing nozzle must produce a fine fog, not droplets (peristaltic pumps). It must operate on the Venturi principle (ASTM B117), as peristaltic pumps are not recommended. The pressure of the bubble tower can control the distance of the atomization flow. Solution droplets are not acceptable during the atomization process.

ASTM, ISO, and JIS standards require that the saline solution be atomized indirectly onto the samples; therefore, direct atomization over the specimens must never occur. The fog flow (atomized saline solution) must be evenly distributed from top to bottom (floor), and the use of a fog dispersion tower with a cone is recommended. Fog collection is critical to achieving optimal test results. Uniform and consistent collection is required by ASTM, ISO, and JIS technical standards.    

Internal Chamber Dimensions:

The chamber must be designed to ensure homogeneity and proper distribution of the fog (spray). Internal chambers smaller than 35.3 cu. ft (1 m³) can cause undesirable effects in fog (spray) distribution, dry-off, temperature control, turbulence presence, and insufficient distances between the inner walls of the test chamber and the atomizing nozzles, as well as between the nozzles and the specimens. (ASTM)

Sample Positioning Inside the Test Chamber:

The positioning of test specimens in the salt fog chamber during testing must comply with the following conditions:

• Specimens must be supported or suspended with the surface of interest facing upward at an angle between 15° and 30° from the vertical. It is recommended that the specimen orientation within the chamber be consistent to minimize variability.
• Specimens must not come into contact with each other or with any metal.
• Each specimen must be positioned to allow unobstructed exposure to the fog.
• Saline solution dripping from one specimen must not fall onto another.
• The positioning of specimens may also be defined by agreement between the parties involved.

Recommended Positioning of Coupons (ASTM B117):

Proper positioning of coupons is recommended to prevent corrosion products from dripping from one coupon onto another, thereby avoiding distortions in the test results.

Proper positioning of coupons, ISO 9227, is recommended to prevent corrosion products from dripping from one coupon onto another, thus avoiding distortions in the test results.

Quality: Salt / Corrosive Agents / Water / Compressed Air:
Control of these items is essential for the accuracy of the test results.

Salt Quality Specifications:
Salt (NaCl) purity limits and concentrations of undesirable chemical elements must be considered. Refer to ASTM B117, ISO 9227, JIS Z 2371, among others. Please refer to our CORRO SALT.

Water:
Water must comply with ASTM D1193 – Type IV (Max. 5 µS/cm). Water deionizers are recommended to achieve the required water quality.

Compressed Air:
The compressed air supply to the bubble tower (saturator) must be free of grease, oil, and dirt before use, having passed through filters. This air must be maintained at sufficient pressure at the base of the bubble tower to meet the working pressure requirements.