If you own a farm of any sort, your barn or silo probably has a drain over which is a grate; car washes also have grates over the drains in the wash bays, and you may even need a drain and a grate over it outside your commercial property if it's prone to flooding.
The type of grate you choose is very important, as it will help control the flow of water and solid materials into the drain, while also needing to be strong enough to withstand foot traffic or vehicle traffic. Note a few terms you might need to learn when choosing a new trench grate, so you're sure to get one that works for your property in particular.
This refers to the weight that a drain grate can manage. For locations like a car wash, don't assume that putting a drain in the middle of a bay will mean that no one would ever drive over it, but invest in a high load capacity grate. Consider, also, the needed load capacity for your barn or silo, so the grate is strong enough to hold up under the weight of your tractor. For walkways, you may need a much lower load capacity, although you still want to consider the weight of motorbikes and other heavier objects that could drive over the grate.
Grates may need a chemical and heat resistance, depending on their use. In a car wash, the water used during the wash cycle can get very hot, and the detergents and waxes used for cars are considered chemicals, so choose a grate with a high resistance to both. If the drain is in a production facility, you may also need one that is resistant to chemicals.
Slot openings are, of course, the size of the slots on a grate. When choosing these openings, never assume that something larger will be better; smaller slots will slow down the flow of water so the drain doesn't get backed up. They're also better for walkways, so that no one catches the heel of a shoe or literally trips on the grate. Smaller slots can also allow solid matter to be caught along the grate and dissolve in the pooling water before it drains, so you may have less risk of clogs forming.
On the other hand, you may not want solid matter like seeds and hay sitting along the grate, and a wider slot would be better for the silo floor.