There are a few different choices when it comes to trench drain grates. There are different cover options and slot options. There are different sizes, materials and configurations also. We will keep this article geared toward cast iron grates. We will look at cover styles, size choice and frame choice.
A few things play a major role when looking at cover styles. First, the type of traffic expected. Pedestrian and ADA grates have small slots. For example, slots that are smaller than the heel of a shoe so the heel won’t get stuck. The slots can go in various directions also depending on the specification. Perforated grates are sometimes opted for in breweries. These are small holes equidistant from one and other. The load bearing and water expectation will also be a factor. Heavier loads will call for product tensile strength that’s appropriate. Trench grates for airports have to be strong enough to handle the load of a plane. Also, bolts are sometimes employed so the trench grates stay fastened and don’t get shifted by the engine pressure. The larger the expected waterfall the larger the size. Similarly, the larger the area to drain the larger the grate. Generally speaking 4” to 6” is usually for pedestrian and light traffic applications and 8”-14” is for more heavier duty applications. This rule does not always hold true. If you are replacing the grates and the frame is still intact and preserved you may not want to use the frames. Trench grates also can be rated in the class load bearing scale. The 12” wide grate is the go to standard in New York for trench grates that go on precast channels or go on a concrete pour. Neenah foundry makes a great 12” wide trench drain grate that can be configured with bolts. We also have another trench drain grate by NDS Filcoten which is great for heavy duty loads.
Cast iron grates can be made in grey iron and ductile iron depending on a few factors. Load bearing being an important one. Generally speaking, ductile iron has a higher tensile strength than grey iron.
Cast iron trench drain grates are a go to solution for a variety of linear drainage applications.