Drains are not sexy. They are not shiny, like a new combi oven. They do not stand out in a room like an 80-gallon kettle. They cannot wash racks of dishes at the speed of light. But what they can do is save you a huge headache when located and coordinated appropriately.
Let’s Talk Drain Basics
There are two different types of waste connections: indirect and direct. An indirect waste pipe does not connect directly with the drainage system. It discharges into the system through an air gap. Imagine your three-compartment sink….at the bottom of the sink are your pipes emptying out soiled water. There is a physical “gap” between the end of that pipe and the floor drain below it. This “gap” prevents contaminated water from backing up into your water supply. These indirect waste connections are seen mostly with prep sinks, dishwashers, and combi ovens. In case you are wondering why an “oven” would require a floor sink, combi ovens also utilize a wash cycle that dumps water. A direct waste is just that – it connects directly to the sewer line in one continuous pipe. This is seen with hand sinks and is typical in residential homes.
As underrated as drains are, it is a costly mistake if they are not located appropriately. It is good practice to place area floor drains (sometimes just called floor drains) every 12 feet. (Check with the local jurisdiction to confirm your project’s code requirements.) Typically, they are a 4-inch diameter grated hole that is flush with the floor. They are used to remove free-standing water/grease.
A floor sink is normally a 12” x 12” basin, installed in the floor structure. It is connected to a waste pipe. They can be partially covered with grating or even supplied with a dome to prevent back splash. A floor sink is used where a piece of equipment requires an air gap and dumps a significant amount of water.
While floor sinks can hold some capacity as it drains, it is not capable of holding an unlimited amount. One must consider how the operator will be using the equipment, how many pieces of equipment will require drainage, and where they will be in the facility. If you have four combi ovens, do you really want them all routed into the same floor sink? While the sink may not overflow during service, someone will inadvertently run all the wash cycles simultaneously causing a potential flood. Will the operator dump all filled compartments of a three-compartment sink at once? Normally someone only does that once – and then they realize their feet are wet and they have a mess to clean up.
A floor trough acts like a drain or channel for water/waste but on a grander scale. They can be seen in front of an ice machine, kettles or in dish areas…to name a few places. They are designed for more volume than a typical floor sink. Just because a floor sink/trough is located per the equipment specs, it does not necessarily make it an ideal location. Structural issues play a large factor in locating floor troughs and floor sinks. For example, will duct work run under your location? What is the slab depth? Will the building have nearby columns that interfere with your proposed location? The list continues. Regardless of whether this is an existing building or new construction, this is where diligent coordination with the Plumbing Engineer and Structural team must occur.
Some Good Tips
Keep in mind some of these tips to avoid coordination pitfalls:
- A floor trough should cover the full pour path of the equipment it is servicing.
- The floor should be sloped 1/8” per foot towards the drain to prevent water from pooling.
- The legs of the equipment should never sit on the trough or floor sink grating. This equipment is especially heavy and can break through the grating.
- Grating should be removable for maintenance and cleaning access whether it is a floor sink or trough.
- Drains should be located close to the equipment. This avoids long, expensive copper line runs.
- The use of a smaller funnel floor drain should be considered instead of a floor sink when possible. This minimizes cost.
- And always think through drain location as it pertains to foot traffic to avoid potential trip hazards.
Avoid the Headache!
What do you do when your drains are not located properly? Throw up the white flag and surrender? There is no such thing as surrender in the foodservice world! If it is a minor infraction, the operator can create a work-around. So, for example, one can clean a kettle and pour soiled water into a drain caddy to be dumped elsewhere. Not a perfect solution but adequate for the situation. If it is a big “oops” and the slab is already laid, then it may have to be dug up and repoured. The jack hammer breaking apart the slab will not only give you a headache, but it will also have you crying in your sleep from lost revenue. Coordination is the key to a good night’s sleep.
By: Tracy Diaz, Project Designer | Germantown
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