925 DETECTABLE WARNING SURFACES
From MDOT Policy Manual
- Detectable warning surfaces shall conform to the current accessibility guidelines of the Americans with Disabilities Act (ADAAmericans with Disabilities Act). The Office of Materials Technology (OMT) maintains a Qualified Products List (QPL). Manufacturers seeking inclusion of their product on the QPLQualified Products List Award—The decision by a procurement agency to execute a purchase agreement or Contract after all necessary approvals have been obtained. shall submit certified test results showing conformance to the properties in 925.07, as well as installation instructions and the types of adhesives and sealants required.
- Warning surfaces shall be either flexible or rigid. If there is a change in the composition of a qualified product, the manufacturer shall notify OMT and submit new test results showing conformance with 925.07.
- 925.02.01 Pavers. Type III Brick Pavers shall conform to the requirements of C 902, Class SX, Type 1, and Application PX. The pavers shall be 2-1/4 x 4 x 8 in. with square edges and a surface meeting 925.03.
925.03 CONFIGURATION AND DIMENSIONS.
- The warning surface shall consist of a system of truncated domes having a base diameter of 0.9 in. to 1.4 in., a top diameter 50 to 65 percent of the base diameter, and a height of 0.2 in. The domes shall be arranged in a square grid with center to center spacing of 1.66 to 2.35 in.
- The color shall be homogeneous across the surface of the material and contrast with adjoining surfaces.
- The top surface shall have an identifier that uniquely distinguishes the manufacturer. Brick pavers are excluded.
TYPE DESCRIPTION PHYSICAL TEST REQUIREMENTS Type I Cast in Place A, B, C, D, E, G Type IIa Surface Mount, Rigid A, B, C, D, E, G Type IIb Surface Mount, Flexible A, B, C, D, F, G Type III Brick Pavers 925.02.01 Type IV Prefilled Pavers A, B, C, D, G
925.07 PHYSICAL PROPERTIES.
PROPERTY TEST METHOD SPECIFICATION LIMIT A Slip Resistance Coefficient C 1028 (dry method) 0.80 minimum B Abrasive Wear, index C 501 150 minimum C Fade (UV) Resistance/Color Retention D 4587 Fade or Change in color after 2000 hours less than ΔE =5* D Freeze/Thaw Resistance C 1026 No disintegration E Adhesion/Bond Strength, pull off C 482/C 882(as appropriate) No adhesion failure F Adhesion/Bond Strength, peel D 903/D 429 (modified as appropriate) No adhesion failure G Contrast Contrast percentage formula** using E 1349 to determine cap Y brightness/light reflectance values (LRV) Current ADAAmericans with Disabilities Act requirement***
- *Chromaticity coordinates (L*a*b* system) checked in conformance with D 2244, before and after test.
- **Contrast % = [(B1 – B2)/B1] x 100,
- where B1 = (LRV) of the lighter area, and B2 = (LRV) of the darker area
- ***For the purpose of determining whether a material meets acceptable contrast criteria, use actual cap Y brightness of detectable warning surface, and assume a value of 15 for the cap Y brightness of cured concrete, or a value of 3 for asphalt wearing surfaces to determine percentage difference. Detectable warning surfaces to be installed on other materials are required to undergo additional testing.