There are a number of American standards that make reference to grate loading. There is no current standard that specifically deals with trench drains of different widths.

Common standards referred to in North America:

ASME: A112.6.3-2001 Plumbing standard relating to internal drains. Test blocks are 3.5” diameter and are rated to 10,000lbs - 1,039psi. AASHTO Standard Specification for Highways Bridges Standard relating to design for bridges. Loadings are dealt with by wheel ‘footprints’ and axle ratings. No specification is given for measurement of the performance of trench drains. General specifications relate to vehicle loading up to HS25. Maximum truck weight 90,000lbs - 3 axles. AASHTO M306-05 acknowledges the addition of HS25 as referenced by some trench drain manufacturers.		AASHTO: M306-05 Drainage Structure Castings Standard relating to castings used in roadways. Test blocks are 9” x 9” and maximum rating is 40,000lbs - 494psi A-A60005 Federal Specifications (Previously RR-F-621E) General federal product specification aimed at manhole covers and catch basin grates. Test blocks are 9” x 9” and maximum rating is 25,000lbs - 309psi FAA AC: 150/5370-10 - Item D-751 Airport standard that covers manholes, catch basins and inspection holes. No measurement or specification given for testing.		FAA: 150/5320-5B & 6D Standard relating to airport drainage and pavement designs. Load tests up to 100,000lbs, but no specific test block size specified. ‘200,000lb proof load’ The lack of a very heavy duty test standard created the need for a line of measurement’. Manufacturers of cast iron access covers used the structure of the RR-F-621E standard with 9” x 9” test block but promoted the use of a 200,000lbs proof load - 2,469psi. Although no independent standard refers to this measure, it has become widely accepted as a ‘line of measurement’ for very heavy duty loadings. Most of these standards refer to catch basin or cast-in-place grates, which are larger than most trench drain grates.
DIN 19580 / EN 1433 The only standard written specifically for trench drains, and internationally recognized, is DIN 19580. DIN 19580 accounts for different widths of grates. For trench drains less than 8” wide, the required test block for load testing is 10” long by 3” wide. For trench drains 8” and 12” wide, the test block is 10” by 6”; for trench drains over 12”, the test block is 10” diameter. This ensures that the full force of the test load is directed onto the grate.		DIN 19580 is being superceded by EN 1433. EN 1433 tests products in exactly the same method as DIN 19580 with the same load categories, up to 202,320lbs - 4,182psi. As with DIN 19580, EN 1433 offers testing methods for both the complete trench drain and individual grates. It accounts for both proof loading and catastrophic failure.

Importance of using correct test block
The diagram below shows test block sizes required by the various load standards available in North America, relative to a 4”, 8” and 12” trench. To be a reliable grate test, the test block should fit inside the internal width, otherwise the load is transferred onto the grate supports.

Incorrect testing of products by using wrong sized test blocks can lead to early failure once installed.

Load test using oversize test block Test load applied to a grate to suit a 4” clear opening trench through a 9” x 9” test block. The grate is not being tested - the load is taken by the supports rather than the grate. Any results from this type of grate test are questionable.
DIN 19580 load test - with relevant test block A 3” x 10” test block applied to a similar grate - the full test load is being applied to the grate giving a meaningful result.

Loading comparison of DIN 19580 to US test standards
The most common rating required for performance in North American for grates / covers etc, is a 'PSI Loading'. The bar chart below provides a PSI comparison between DIN 19580 and current standards on this basis. The PSI rating is proportional to the size of test blocks.


ACO believes DIN 19580 is currently the most recognized, independent standard to measure product performance.