ANSI BHMA A156-18:2000 pdf download.AMERICAN NATIONAL STANDARD FOR MATERIALS & FINISHES
3.1 Control Method: These test methods do not predict the performance life of the finishes in actual use but are used as a quality control method to ensure consistent finish quality. Actual product components shall be used except where otherwise specified.
3.1.1 Significant Surfaces: Surfaces on which a controlled deposit ordinarily cannot be obtained such as holes, edges, recesses, bases of angles, and similar areas are exempt from the requirements for significant surfaces.
3.1.2 Components without surfaces which are compatible with the prescribed test methods, shall use a finished flat test panel using substrate of the same base material of the actual product or component. The flat panels shall have a minimum exposed area of 2.50 x 3.75 in (64 x 95 mm) and shall be 0.064±0.004 in(1.6±0.1 mm) thick. Other materials are pemitted to be specified by the affected ANSI A156 product standards.
3.2 Salt Spray Test. This test shall be conducted in accordance with ASTM B 117-95 Standard Method of Salt Spray (Fog) Testing.Parts shall withstand exposure for the time specified in the applicable ANSIBHMA A156 Series Standard without base material or substrate corrosion exceeding one spot visible to the unaided eye per one square inch (25.4 square mm) of significant surface and without any spot larger than 1/16 in (1.6 mm) in diameter. Staining shall not exceed 5% of the significant surface area of the component under test and without any spot larger than 1/4 in. (6.4 mm) in diameter.
3.3 Humidity Test. This test shall be conducted in a chamber having a 95% ± 5% relative humidity at 100 degrees F±5 degrees (38 degrees C±3 degrees) for the times specified in the applicable ANSIBHMA A156 Series Standard. The parts shall be allowed to stabilize at room temperature for 30 minutes before they are examined. Blistering or staining of the part shall not be visible to the unaided eye. The coating shall,within an additional 15 minutes, pass a pencil hardness test (see 3.4) as specified in the applicable ANSIBHMA A156 Series Standard and shall pass the method B Cross-Cut Tape Test as defined in ASTMD 3359-95A Method for Measuring Adhesion by Tape Test. The rating shall be as specified in the applicable ANSI/BHMA A156 Series Standard.
3.4.2 Abrade the lead with #400 grit sandpaper and finish with light pressure to minimize grooves in the abraded surface. The circular edge shall be sharp, not serrate, when inspected with 5X magnification after each abrading. Repeat the abrading as required until the inspected edge is sharp. By rotating the lead holder after each test either 180 or 120 degrees±1 degree, three tests maximum shall be performed per abrading.ANSI BHMA A156-18 pdf download.