Mastering Trench Drain Grates:

A Deep Dive into Load Classes for North American Engineers and Contractors

Embarking on a construction or infrastructure project requires meticulous planning, and one crucial element often overlooked is the trench drain system. In this comprehensive guide, we'll explore the intricate world of trench drain grate load classes, catering to the specific needs of civil and mechanical engineers, civil architects, landscape architects, and contractors across North America.

Navigating DIN 19580/EN1433 Load Classes

I Load Class A (up to 15kN - 3,372 lbs per foot):

In accordance with the EN1433 standard, Load Class A is tailored for pedestrian and cyclist traffic. Grates within this category are capable of supporting loads up to or exceeding 3,372 lbs per foot, ensuring both safety and reliability.


Application examples: Light traffic areas, residential use, gardens, patios, landscapes, pedestrian zones, bicycle paths, and cart pathways.

I Load Class B (up to 125 kN - 28,100 lbs per foot):

Medium Duty Load Class B is engineered for areas experiencing light pneumatic tire traffic, commonly found on sidewalks and residential parking. With a design load of at least 28,100 lbs per foot, these grates offer dependable performance.


Application examples: Sidewalks, pedestrian zones, car parks, garages, driveways, areas for domestic cars, light trucks, small planes, and low-traffic parking lots.

I Load Class C (up to 250 kN - 56,200 lbs per foot):

Designed for heavy-duty commercial applications, Load Class C grates boast a robust design load of at least 56,200 lbs per foot, catering to environments with substantial demands.


Application examples: Areas accommodating forklifts with pneumatic tires, medium-sized vehicles, and commercial parking lots.

I Load Class D (up to 400 kN - 89,920 lbs per foot):

Stepping into the realm of Extra Heavy Duty, Load Class D is engineered to handle pneumatic forklift traffic on roads and highways, meeting stringent H-20 Load Ratings. These grates support a design load of at least 89,920 lbs per foot.


Application examples: Parking lots, warehouses, and main thoroughfares.

I Load Class E (up to 600 kN - 134,800 lbs per foot):

Load Class E addresses the challenges posed by commercial solid tire traffic patterns and impacts from steel struts or metal wheels. With a design load of at least 134,800 lbs per foot, these grates are ideal for demanding industrial environments.


Application examples: Industrial zones, construction equipment/vehicle pathways, loading docks, heavy aircraft areas, airports, and distribution centers.

I Load Class F (up to 900 kN - 202,320 lbs per foot):

Reserved exclusively for airport traffic, Load Class F grates are engineered to withstand extreme loads, boasting a design load of at least 202,320 lbs per foot. These grates necessitate an engineer-designed system for installation.


Application examples: Highways, roads, airports, terminals, port docks, and locations with exceptionally heavy weight conditions.

Unveiling ANSI/ASME A112.21.1M Load Classes

I Light Duty (up to 2,000 lbs):

Our journey begins with the Light Duty class, tailored for pedestrian foot traffic. Grates in this category are engineered to safely support live loads under 2,000 lbs, ensuring seamless functionality in spaces where people tread.

I Medium Duty (2,000 lbs to 4,999 lbs):

Moving up the spectrum, Medium Duty grates are designed for areas experiencing light pneumatic tire traffic, such as sidewalks and residential parking. These grates can bear live loads ranging from 2,000 to 4,999 lbs.

I Heavy-Duty (5,000 lbs to 7,499 lbs):

For spaces with commercial pneumatic tire traffic patterns and tractor trailers, the Heavy-Duty class steps in. Grates in this category handle live loads between 5,000 to 7,499 lbs, ensuring durability in high-traffic areas.

I Extra Heavy-Duty (7,500 lbs to 10,000 lbs):

As the demands increase, the Extra Heavy-Duty class comes into play. Engineered for forklift traffic, roads, and highways, these grates handle live loads between 7,500 to 10,000 lbs, meeting H-20 Load Ratings.

I Special Duty (Over 10,000 lbs):

The pinnacle of load classes, Special Duty grates are crafted to handle airport traffic. With a capacity for live loads exceeding 10,000 lbs, these grates ensure robust performance in demanding environments.

AASHTO H-20, HS-20, H-25, and HS-25 Loadings: Beyond Grates

<p><strong>AASHTO H-20 and HS-20 Loadings:</strong></p><p>The AASHTO defines H-20 loading as a two-axle truck with a maximum dual-wheel load of 16,000 lbs. HS-20 loading, on the other hand, is attributed to a tractor truck with a tandem axle semi-trailer, also with a dual-wheel load of 16,000 lbs.</p><p> </p><p><strong>AASHTO H-25 and HS-25 Loadings:</strong></p><p>In addition to H-20 and HS-20, AASHTO introduces H-25 and HS-25 loadings. H-25 loading pertains to a two-axle truck with a maximum dual-wheel load of 25,000 lbs, while HS-25 loading is associated with a tractor truck with a tandem axle semi-trailer and a dual-wheel load of 25,000 lbs.</p><p> </p><p><strong>FAA Advisory Circular AC 150/5320-6D:</strong></p><p>The FAA outlines aircraft loading as 100,000 lbs placed over a 9” x 9” (229 x 229 mm) area, emphasizing the need for robust drainage systems in airport environments.</p><p> </p><p><strong>ADA Guidelines for Gratings:</strong></p><p>The Americans with Disabilities Act (ADA) mandates specific guidelines for slot width limitations on gratings in walkways. Elongated slots must be placed longitudinally and perpendicular to the dominant direction of travel for accessibility. Slot width ½ inch (13mm).</p><p> </p><p><strong>Heel Proof Design:</strong></p><p>"Heel Proof" design, with slots or perforations less than ¼” (8mm) in width or diameter, ensures safety and compliance with industry standards.</p><p> </p><p><strong>Conclusion: Empowering Your Project with the Right Trench Drain Grates</strong></p><p>In the intricate tapestry of infrastructure projects, the right trench drain grates are the unsung heroes. By understanding the nuances of ANSI/ASME and DIN load classes, engineers, architects, and contractors can ensure their projects are equipped to handle the diverse demands of pedestrian, vehicular, and even airport traffic. For tailored solutions and detailed specifications, our team is ready to collaborate on crafting efficient and resilient trench drainage systems that stand the test of time. Contact us today and let's build a foundation for success together.</p>

Kastriot Malci
Technical Support Manager
BG-Graspointner | Canada