Trench Drains and Slotted Drains for Industrial & Manufacturing Facilities

Industry is very difficult to categorize and generalize as there are many very specialized processes that have their own needs.  Industrial trench drains are used to capture fluids used to cool machinery, capture wash water from washing equipment and products, contain and treat chemicals used in various processes, contain spills, run wires and pipes to machinery, and any number of other uses.

Most industries are tightly regulated and are no longer allowed to dump waste down the drain.  Manufacturers are therefore looking to capture any fluids that are used and recycle the fluid or have their own waste water treatment facilities.  Often times some sort of filtration and/or separation is required in the trench drains or at the outlet locations to facilitate this process.

Trench drains are also advantageous because they allow for flatter floors.  This allows materials to be stacked higher, forklifts to traverse easier without spilling materials, equipment to sit level, and makes for a less dangerous work environment.

Trench drains in industrial/manufacturing environments can see heavy loads or none at all, harsh chemicals or only water, large quantities of debris or none at all, abrasive materials, flammable materials, and many other damaging conditions.  All these conditions need to be carefully weighed to determine what type is best for an application.  These applications are good places to call in an expert to carefully evaluate the situation and give their best recommendation.

Design Considerations

Sizing the drain

• Four things must be considered when sizing a industrial trench drain;  Is there an instantaneous load such as a tank dumping into the system;  What are the constant loads such as continuous process fluids?  How much debris will be in the fluids being captured by this trench drain.  What is the desired cleaning frequency.
• Higher velocities in the bottom of the trench drain can sometimes reduce the need to clean out debris as often.  Some industrial trench drains have very dense solids that no matter how fast the flow they will still fall to the bottom.  For these cases, design the trench drain much larger than the flow would require to allow space for sediment to build up.
• For more details on sizing industrial trench drains review the channel drain flow charts to confirm that the trench drain you select will handle the required flow rates.

Choosing the channel

• Check for chemical loading.  Many industrial trench drains carry harsh chemicals that need special channel drain properties.  Make sure you know what the chemicals are and what temperature they will be when they come in contact with the drain channel.  Note that as fluids traverse a concrete slab the temperature drops significantly.  To review chemical resistance properties of the Dura-Trench channel drains go to our Chemical resistance guide.
• Many industrial trench drains have abrasive particulate in the liquid stream.  Determine how abrasive the materials are that go into the trench drain.  Constant cleaning of the trench will also be abrasive to the trench drain channel.  The more abrasive the material, the thicker the walls of the trench drain should be.  Stay away from soft materials and thin wall trench drain systems.  Dura Trench industrial drains allow you to specify the wall thickness you need and also have ceramics in the proprietary blend to combat the abrasive wear that can happen.
• Thermal shocking of the trench drain can also be an issue.  Industrial and manufacturing facilities can have large swings in temperature.  This can happen during certain process or cleaning events.  When this temperature change happens the trench drain materials expand and contract.  If large temperature changes are expected be sure the channel material moves at the same rate as the concrete encapsulating it.  Avoid thermoplastics (plastics that can be melted) that have a high thermal expansion coefficient.  Choose fiber reinforced polymers, metal, or concrete forming products.  For more information see material properties.
• Many industrial drains are outside the building.  For exterior applications ensure that the drain will not degrade with exposure to ultraviolet light (UV light).
• Industrial drains often have heavy loading of forklifts, pallet jacks, or other carts with small hard wheels. Hard tires produce extreme point loads on the trench drain grates, frames, and in some cases the channel drain body.  Industrial applications need a heavy duty frame to transfer the loading from the grate to the surrounding concrete.  Be cautious of using a trench drain where the frame has little bearing surface in the concrete to transfer this load.  If the loads are transferred to the channel drain body they may prematurely fail.  Industrial drain frames need to be checked for chemical resistance also.  Heavy duty frames are typically available in epoxy coated steel, galvanized steel, stainless steel, fiberglass, plastic, and Ductile Iron.
• As a general rule, if you are coating your concrete with an epoxy or urethane floor you should be sealing the channel drain joints with a similar material.  Select an industrial drain with fewer joints because your odds of getting them properly sealed is increased.  Be sure the specifications call for the channel drain joints to be sealed and how to perform the work.  If you want this done properly you must specify how and stress this to the contractor.  Stainless steel trench drains should be welded together with a continuous water tight bead.  Fiberglass and polymer concrete channels should be properly prepared by roughing up the joint and then using an appropriate two part sealant.  Thermoplastic channels (such as HDPE, PE, PVC, etc) should be welded together with a continuous heat welding process.

Selecting the grate

• Industrial drain grates typically use ductile iron, galvanized steel, stainless steel, or fiberglass grates.  These materials handle the heavy loads and abuse of an industrial environment.  When chemicals or cleanliness are a concern the chemical resistance and clean-ability of the grate should be reviewed.  For these applications stainless steel or FRP (fiber reinforced plastic grating) are often selected.  These trench drain grating materials are more expensive but will last longer than other materials.  There are industrial drain applications that only have pedestrian traffic and can use a thermo-plastic grate to reduce cost.
• Industrial drain grates are offered in many standard sizes and patterns.  The channel drain grate openings can be small to keep trash and debris out of the trench drain system.  Conversely, they can be large to allow the debris to fall through the channel drain and get flushed down the system.  When small openings are preferable, ensure that they will not be too restrictive to the flow into the trench system.  Small openings are easy to plug.  Plugged openings will not allow fluids to enter the channel drain system at the required rate.  Smaller trench drain grate openings will need to be cleaned more frequently.  Channel drain grates with large openings may allow large objects into the trench drain channel.  This may cause staff to remove heavy grates frequently to clean the channel drain.
• Be selective when choosing the method of locking down the grates.  Many industrial drains may not require locks due to cleaning frequency.  If channel drain grate locks are required for high speed traffic be sure to verify how easy they are to remove and what materials they are made from.  Locking mechanisms need to be comprised of a material that can handle the process chemicals.  They should also not corrode easily so that removal is easy.

Designing the layout

• Trench drains can be straight or have turns and intersections.  Industrial channel drains should be placed to catch fluids before they enter major traffic areas.
• Industrial drains with a lot of flow can use a combination of channel drain sizes.  Smaller finger trench drains can run into larger header trenches to reduce cost.
• Check the depth of the channel drain system to avoid conflicts with piping and buried utilities.
• Outlets piping should be placed to minimize underground process and drain piping.  Where possible keep trench drain channels shallow to save cost.  Plan trench drain outlets to reduce underground piping turns.  Pipe elbows can plug with debris if not properly sized.
• Industrial drains with chemicals in the trench drain SHOULD NOT allow any neutral or flat sections.  A slope of 1% or more is recommended for chemical applications.  When chemicals sit in the channel drain body it increases chemical attack due to increased exposure times.  By keeping drains sloped properly it will reduce long term problems.
• Many equipment and process trench drains make turns to go around equipment.  When possible make the corners the shallow points.  Flow is restricted through channel drain corners.  In many industrial applications this is not possible and the flow must go through turns.  Design the layout to minimize turns if possible.  Where turns are necessary make sure that the cuts are smooth and the inverts should line up.  Dura Trench can make all these turns for you in the factory.  If the flow velocity is high or needs to be maintained reduce turns to 45 degrees.