7.4 Quality Assurance Requirements
7.4.1 Assurance of Lead-Free and Hexavalent Chromium-Free Content
Vendors shall provide written assurance that the coatings are free of lead, hexavalent chromium, and cadmium. If paint from section 7.1 is used, documentation of the brand and color identification from the manufacturer is acceptable. For coating materials other than those listed in section 7.1, vendor may be required to procure independent laboratory testing of the paint. The independent laboratory shall be accredited under EPA’s National Lead Laboratory Accreditation Program. The sample shall be tested to ASTM standards, example: ASTM D4834 "Test Method for Detection of Lead in Paint by Direct Aspiration Atomic Absorption Spectroscopy". The test shall be performed on a dry coating sample scraped to bare metal. Laboratory test results shall be reported directly to Caltrans.
Coatings are subject to random testing by Caltrans for prohibited materials.
7.4.2 Assurance of Air Quality Compliance
All coating materials and application processes used inside California for Caltrans equipment shall comply with requirements of the state (California Code of Regulations, Title 17, Public Health; Div. 3, Air Resources), and local air district.
7.4.3 Test Panels (Optional)
When powder coat is used, destructive test panel(s) of the same base material that undergo the same surface preparation and coating process as production parts may be submitted with the pre-production unit(s). Test panel thickness shall be at least 14 gauge and measure at least 6 by 6 inches. The test panel shall be primed with the same powder as part(s). Post primer bake and prior to topcoat application, one half of one side of the test panel shall be masked such that no topcoat is applied on the masked portion. The test panel(s) shall be temporarily fixed to each unit during the powder coating process and removed by QA inspectors during the inspection process.
7.4.4 Solvent Resistance Test
When Fleet White (or equivalent) color is specified, the topcoat shall be tested for solvent resistance. Solvent resistance testing may also be done for other color finishes. The topcoat sample area shall be tested by at least 20 double rubs of a Methyl Ethyl Ketone (MEK) saturated cotton swab with approximately 2.5 to 4.5 pounds pressure applied at a 45 degree angle. Refer to ASTM D5402 for further information. The topcoat shall retain luster and the sampling cloth or swab shall be free of color material.
7.4.5 Visual Inspection Criteria
The paint surface shall be visually inspected for undesirable characteristics listed in Appendix A. Acceptance/rejection is at discretion of the QA inspector.
7.4.6 Coating Thickness
The QA inspector may perform a dry film thickness test at their discretion. The sample area and number of tests is at discretion of the QA inspector. Refer to section 7.3 for required film thickness.
7.4.7 Color Match
Caltrans maintains a set of standard paint color samples which can be used for color match if necessary. Color match between the sample and finished product shall be under daylight conditions. Color match is at the discretion of the QA inspector.
7.4.8 Adhesion, Test 'A'
ASTM D3359, adhesion test method 'A' is generally intended for coatings of more than 5 mils total thickness. This test is performed with an "X" scoring pattern as shown in Figure 'A'. Tape is applied to the scored area and quickly pulled back on itself as close to the surface as possible. Refer to ASTM standard for required procedure. Results of 4A or better shall be achieved using this test method as shown in Table 'A'. Sampled test area may vary and shall be at the QA inspector's discretion.
| Figure 'A' |
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TABLE 'A' - ASTM D3359, Test Method 'A' Classifications |
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Classification |
Description |
Illustration |
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5A |
No peeling or removal. |
None |
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4A |
Trace peeling or removal along incisions or at their intersection. |
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|
3A |
Jagged removal along incisions up to 1/16 inch on either side. |
 |
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2A |
Jagged removal along incisions up to 1/8 inch on either side. |
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1A |
Removal from most of the area of the X under the tape. |
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0A |
Removal beyond the area of the X. |
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7.4.9 Adhesion, Test 'B'
ASTM D3359, adhesion test method 'B' is generally intended for coatings up to 5 mils total thickness or less; however, this method can also be used for mil thicknesses over 5 mils if the adhesion test kit supplier's instructions specify the supplied tool(s) are designed for such use. The test is performed using a crosshatch scoring pattern. Tape is applied to the scored area and quickly pulled back on itself as close to the surface as possible. Results of 4B or better shall be achieved as classified in Table 'B'. Refer to ASTM standard or instructions from adhesion test kit supplier for proper procedure including spacing and number of cuts.
| TABLE 'B' - ASTM D3359, Test Method 'B' Classifications | |||
| Classification | Description | % Area Removed | Illustration |
| 5B | The edges of the cuts are completely smooth: none of the squares of the lattice are detached. | 0% |  |
| 4B | Small flakes of the coating are detached at intersections; less than 5% of the area is affected. | <5% |  |
| 3B | Small flakes of the coating are detached at intersections of cuts. The area affected is 5 to 15% of the lattice. | 5-15% |  |
| 2B | The coating has flaked along the edges and on part of the square. The area affected is 15 to 35% of the lattice. | 15-35% |  |
| 1B | The coating has flaked along the edges and on the squares have detached. The area affected is 35 to 65% of the lattice. | 35-65% |  |
| 0B | Flaking and detachment is worse than level 1. | >65% |  |