Industry is a 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, capture wash water, capture and treat chemicals used in various processes, contain spills, run wires and pipes to machinery, and any number of other uses.  

Most industry these days is tightly regulated and it is no longer allowed to dump waste down the drain.  Manufacturers are therefore looking to capture any fluids that are used and recycle the fluid.  Often times some sort of filtration and/or separation is required.

Trench drains are also advantageous because it allows for flatter floors.  This allows materials to be stacked higher, 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.

Sizing the drain

  • Four things must be considered when sizing the drain;  Is there an instantaneous load such as a tank dumping into the system;  What is the constant load such as continuous process fluids, and how much debris will be in the fluids being captured, and what is the cleaning frequency.
  • Remember that with higher velocities in the bottom of the trench you can sometimes reduce the need to clean out debris as often, however, some materials are so dense that no matter how fast the flow they will still fall to the bottom.  In this case you need a much larger trench simply to catch debris.
  • For more details on sizing interior drains review the flow charts to confirm that the trench drain you select will handle the required flow rates.

Choosing the channel
  • Check for chemical loading.  Many processes use harsh chemicals that need special channel 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 often drops significantly.  To review chemical properties of the Dura-Trench channels go to our Chemical resistance guide.
  • Determine how abrasive the materials going into the drain are.  Also, beware if you constantly clean the drain with shovels.  The more abrasive the material the more you should choose a thick wall drain and steer away from thin plastics toward thicker metals or formed concrete trench bodies.
  • Thermal shock can also be an issue.  If the temperature is controlled and there are large swings in the temperature during the process or during cleaning then be sure that the channel material moves at the same rate as the concrete encapsulating it.  Again, avoid plastics that have a high thermal expansion coefficient.  Choose fiberglass, metal, or concrete forming products.  For more information see material properties.
  • If this is an exterior application also ensure that the drain will not degrade with exposure to ultraviolet light (UV light).
  • Heavy loading of forklifts, pallet jacks, or other carts with small hard wheels produce extreme point loads on the drain channels.  In these applications ensure that you have a heavy duty frame to transfer the loading more evenly to the channel to ensure that the channels do not prematurely fail.  If your application will need a frame to handle more severe loads ensure that it can also handle any chemicals that it may come in contact with.  Heavy duty frames are typically available in Powder coated steel, galvanized steel, stainless steel, fiberglass, plastic, and Ductile Iron.  Learn more about loading of grates and channels.
  • Sealing channel joints should be done if there are any chemicals that need special care.  As a general rule if you are coating your concrete with an epoxy or urethane floor you should be sealing the channel joints with a similar material.  If you want this done properly you must specify such and stress to the contractor that this be done properly.  Stainless channels 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.  HDPE channels should be welded together with a continuous heat welding process.
  • Many manufacturers offer a cleaning shovel to go with their system.  Two of these shovels are  recommended for each facility and information on where to purchase additional shovel heads should be provided to the owner.

Selecting the grate
  • Industry typically uses ductile iron, galvanized steel, stainless steel, or fiberglass grates.  These materials handle the heavy loads and abuse of an industrial environment for a modest cost.  Obviously, when chemicals or food processing are involved chemical resistivity and cleaning become issues leading to stainless steel or FRP (fiber reinforced plastic grating).  These materials are more expensive, especially if you need materials that will still handle the heavy loads.  In some cases, where there is only pedestrian traffic, thermo-plastic grates can be used for a reduced cost.  
  • Grates can be had in many different opening sizes.  The holes can be small if you are trying to keep trash and debris out of the trench drain system, or they can be large to allow the debris to fall through the drain and get flushed down the system.  If small openings are chosen, check to ensure that they will not be the limiting factor on the trench system.  If many of these holes are plugged, the fluids may not be able to enter the system at the required rate.  Also, remember that the smaller the opening the more frequently the grating will have to be thoroughly cleaned.
  • Be selective when choosing the method of locking down the grates as the locking mechanisms need to be comprised of a material that can also handle the process chemicals.

Designing the layout
  • Trench drains can easily be turned, intersected, or simply run straight.  The drains should be run in such a fashion as to catch the fluids before they enter major traffic areas.
  • In some cases it is beneficial to run smaller trenches into a larger header trench to save cost.
  • Be aware of the depth of the system that you are going to use to avoid conflicts with piping and other buried utilities.
  • Outlets should be placed to minimize piping, but try to avoid making the outlets too far apart because the trench depth will increase and so will the system cost.  
  • If there will be any chemicals in the trench drain DO NOT allow any neutral sections.  A slope of 1% or more is recommended in order to ensure that chemicals do not sit at any location in the trench drain and cause long term problems.
  • To get the drain around a machine you will need to turn the drain around the corners.  If possible make the corners the shallow points as flow is restricted through the corners.  In many applications this is not possible and the flow must go through the turns.  Design the layout to minimize turns if possible.  Where turns are necessary make sure that the cuts are smooth, the inverts should line up, and the joint should be sealed with a quality rigid two part epoxy.