Trench Drain Systems for Animal Hospitals, Kennels, Vet Clinics & Pet Resorts

Veterinary clinics and Animal Hospitals require trench drain systems for the cleaning of the animals pens or kennels.  For both interior and exterior kennels, the accepted method is to place a trench drain at the front or back of the pens to wash urine and fecal matter into.  The best method is to cast a trench drain into the concrete slab, however, you can purchase cages with a trench drain built into a raised floor.

When casting a trench drain system into the concrete it is best to design the kennel area so that the cages can be washed from the isle to the back of the kennel.  This requires putting the trench drain at the back of the cages.  This allows the staff to wash the hair, urine, and fecal matter to the trench drain while rolling their cleaning supplies and hose down the isle.  The staff will not get nearly as wet with this design as a layout where they have to enter the cages and try to spray the floors to the center isle.  If your layout will require a grate, you should select a grate that can handle the exposure to urine and will not allow the animal paws to pass through but as large an opening as possible to reduce the cleaning frequency.

During design, plan on placing a flush valve at the shallow end of the trench drain with a wall mounted  valve for flushing the trench.  This will aid in keeping the trench drain and underground piping system flowing clean with minimal maintenance.

Trench drains in animal areas should have hair strainers at the outlet to minimize pipe maintenance.  For trench drains in a grooming area you should consider a larger catch basin with a trash bucket to keep hair from getting into the system.

Demand a minimum of 3″ pipe or preferably 4″ pipe diameter for drain lines that will see fecal matter or hair.  Smaller sizes can plug.  Be sure all trench drain joints are sealed water tight too keep the slab from getting infused with urine.  Concrete is porous and will absorb urine and hold the smell and it will be difficult if not impossible to get rid of the smell.

Design Considerations

Sizing the drain

• For most kennel applications, a 4″ clear trench cross section will be sufficient for the hydraulic loading, hair, and fecal matter.
• The exception to a 4″ drain may be a kennel for larger animals such as primates, cattle, large zoo kennels, etc.

Choosing the channel

• Choose channels that are nonporous.  Porous channels can absorb urine and cause the entire building to have a foul odor.  Concrete formed trenches are not recommended unless they will be coated with epoxy.
• Ensure that you choose a pre-sloped trench drain system and do not allow the use of any flat channels.  The slope of the channel will move the urine down the system and evacuate it keeping the smell down.  Non-sloping trench drains allow some urine to sit in the trench and it will cause severe odors.
• Animal urine is caustic and will corrode some materials.  Check the chemical resistance of the materials being used.  The PH of urine is often seen as low as 4.5 in animals especially when they are sick.  The urine will rapidly eat carbon steel and even damage galvanized steel.  Choose frames from plastic, fiberglass, or stainless steel.
• The channels should receive only foot traffic in these applications so the channel will not need a heavy duty frame.
• Sealing channel joints is critical in this application. If urine is allowed to get in between the joints you will not be able to eliminate the odor and it can deteriorate the concrete behind the channels.  If you want this done properly you must specify the sealant and stress to the contractor that this be done properly.  Polymer concrete and Fiberglass channels should be properly prepared by roughing up the joint and then using an appropriate two part sealant or a single part urethane sealant.  HDPE channels should be welded together with a continuous heat welding process as sealant does not stick to smooth plastics over time.  If using a stainless steel body, weld all seams water tight.
• Make sure the high point on the channel system is plumbed with a 1″ (or 3/4″ line minimum) line and a wall valve to flush the trench drain system and underground piping.  The flush nozzle should be about 1″ off the bottom of the trench at the high point of each line.
• 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.
• Exterior applications or indoor applications that will not be temperature controlled will see severe changes in temperature.  The trench drain materials should have similar thermal coefficients of expansion to that of the surrounding concrete encasement.  For more information see material properties.

Selecting the grate

• Choose a light duty grate that will not be attacked by the urine.  Plastic grates are an inexpensive choice for interior applications and are suitable for most kennel applications.  Fiberglass grates are also a great choice for kennel applications as long as the cut edges are properly sealed before installation.  Stainless steel is the best choice from a durability standpoint, but is considerably more expensive.  Cast or ductile iron can be used but will eventually need to be replaced as the urine will attack the material.  Iron grates are so thick that even though they are attacked they will usually take 20-30 years before they need to be replaced.  Steel should be avoided as the life span of steel is very short in this environment.
• If plastic grates are selected they should be locked into place so that they do not become chew toys for the animals.
• Make sure that the openings on the grate are small enough that animal feet will not get trapped in the grates and cause injury.  The smaller the openings the more frequent cleaning of the grates will be necessary.
• Multiple grate selections can be used.  For kennels that will house larger animals you can select grates with larger openings.  For smaller animals choose grates with smaller holes or slits.  For areas outside the kennels choose grating material based on the expected traffic.
• Be selective when choosing the method of locking down the grates.  The locking mechanisms need to be comprised of a material that can also handle the acidity of the urine.  Typically stainless steel locking devices are used.

Designing the layout

• Lay out trench drain behind kennel walls if possible to eliminate grating concerns.
• The trench runs are best sloped in one direction.  This simplifies the flushing system and cleaning of the trench drain.  In large kennels, it is best to break up the trench runs so that the trench system does not get too deep.
• Try not to use trench drain that will intersect or turn in kennel applications as fecal matter does not like to turn corners.  If a tee section must be used, be sure that the invert of the channel entering the “trunk” line is higher than the invert of the “trunk” line by the height of the radius of the bottom of the trench to avoid complications with the fabrication and installation.