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<\/figure>\n<\/div>\n\n\nPDF versions of this guide<\/a> and the trench drain schematic<\/a> are available for download.<\/p>\n\n\n\n Drains provide an intentional path for wash\nwater and other effluent to leave the produce wash and pack area. This is an\nimportant element of hygienic\ndesign<\/a> \u2013 designing spaces to be cleanable and avoiding\ncross contamination. <\/p>\n\n\n\n Water leaving sinks<\/a>, spray tables, wash lines, barrel or\ndrum washers, dunk tanks, or dump tanks should be intentionally routed away\nfrom the area where produce is being handled to avoid potential\ncross-contamination. This is what drains are meant to do, but there are some\ndetails in their design, installation, and use that should be considered to\nmake sure they work as intended.<\/p>\n\n\n\n The first detail to be considered is which\ntype or types of drain to use.<\/p>\n\n\n\n Direct drains are common when sinks and tanks\nare used. These drains are often fabricated with hard plumbed piping but can\nalso be made of flexible hose. Typically, direct drains are connected directly\nto an outlet of a sink, tank or catch pan under a wash line and provide drainage\ndirectly to an outlet such as a septic tank, catch basin or vegetative swale. A\nhand valve is often installed close to the outlet drain of the vessel to open\nor close the drain to either allow or prevent flow. Direct drains are well\nsuited to lower flow rates and cleaner water with less debris. Plan on\nincluding clean out ports in your drain line.<\/p>\n\n\n\n An air break is often included in direct drains\nfor two reasons. First, an air break can mitigate the impact of backflow\nresulting from an obstruction downstream. In the case of an obstruction or\nclogged drain resulting in a backup, the overflow will occur at the air break\npreventing contact of the effluent with the tank or other vessel above or\nupstream of the air break. Secondly, maintenance, cleaning, and inspection is\neased when an air break is included. More information on backflow prevention,\nair breaks, and check valves is provided in the guide sheet, \u201cBackflow Prevention for Produce Farms<\/a>.\u201d<\/p>\n\n\n\n Spot or Floor Drains are individual drains set in a poured concrete floor<\/a>. What is seen once the floor is poured is just a circular opening which may be covered with a coarse grate or cap. The drain piping is embedded in the floor or run below the subfloor in a wood-framed construction. A general rule of thumb for determining the number of spot or floor drains is to provide one drain for every 600 square feet of floor area. But, also consider the specific planned use of the space and where equipment, tanks, and sinks may be located. If they are all pushed toward the perimeter of the building, it may make sense to have more drains there to provide for dedicated draining and equipment layout flexibility.<\/p>\n\n\n\n Spot drains are generally used when the outlet\nwater flow is limited to a single area and of moderate volume. These drains can\ntypically accommodate some sediment and small pieces of debris. But, it is\nstill important to plan on cleanout ports in the drain.<\/p>\n\n\n\n A Trench drain is a high volume floor drain option that is flush with the floor surface at the top of the drain. They are also sometimes called linear, channel, or gutter drains. Seen from the side, they generally have a \u201cU\u201d shaped cross-section which deepens toward the outlet allowing the top to stay level with the floor while also providing a slope in the drain to carry wastewater away. <\/p>\n\n\n\n There are two approaches to building a trench\ndrain:<\/p>\n\n\n\n Plan for at least a 4\u201d diameter vertical\noutlet with a female fitting set flush with the top of the poured concrete\nfloor of the trench at the outlet. A\nsimple 12\u201d-24\u201d length of 4\u201d pipe can be inserted in the female fitting to\nresult in a stand pipe when in use. This\nwill prevent flow of sediment laden water directly out the drain. The more\nclear water at the top of the standpipe can flow out. The level of the outflow will depend on the\nheight of the pipe insert. Sometimes a coarse grate or inlet screen is\ninstalled to prevent large pieces of debris from flowing out the drain. The\nstandpipe can also be drilled to provide a coarse filtration.<\/p>\n\n\n\n There are several trench drain systems\navailable on the market, including:<\/p>\n\n\n\n There are also distributors who can help you\nunderstand product availability and selection and probably some design work. FW\nWebb (https:\/\/www.fwwebb.com\/<\/a>) is a\ncommon plumbing supply distributor in New England and they distribute these\nsystems as well.<\/p>\n\n\n\n If you choose to build in a trench drain as opposed to using a pre-cast or formed system, there are a few options for custom drain grates and covers. Fiberglass grating<\/a> is commonly used in industrial applications for mezzanines, floors, stairs or drainage areas. These can be cut to fit with typical woodworking tools like a recriminating saw.<\/p>\n\n\n\n If you expect to experience regular heavy traffic over your drain, a galvanized steel grate <\/a>may be a wise decision.<\/p>\n\n\n\n Discharge of vegetable wash water is regulated\ndifferently in each state. Be sure to check with your local and state\nregulatory authorities to ensure your plan is appropriate. Consider the area\naround your wash and pack shed and think about where it would be appropriate to\ndischarge wash water. Direct discharge away from food crop production areas, avoid\nareas with regular crew or vehicle traffic, and do not discharge directly into\nany bodies of water. We have compiled guidance\nfor Vermont growers<\/a> based on discussions with local regulatory agencies. <\/p>\n\n\n\n Finally, consider your maintenance, cleaning\nand inspection plan.<\/p>\n\n\n\n Floor drainage, with proper pitch can be\nmostly maintenance free, however some cleaning, and inspection is required\nespecially with a heavy soil load. <\/p>\n\n\n\n Note the rate at which your drains empty. If you start to notice a slow drain or\nabnormal gurgling it may indicate a partially clogged drain. Addresses clogged drains early can prevent an\nuntimely backflow. As noted above, consider including cleanout ports which will\nmake the inevitable clogged drains easier to deal with.<\/p>\n\n\n\n The steel grates on trench drains can be\nremoved for cleaning the trench with a square shovel to remove the sediment and\ncan then be hosed or and brushed out for cleaning. With minimal ventilation and\nsome time, these drains can also be fully dried once cleaned, which is an added\nproduce safety benefit.<\/p>\n\n\n\n When cleaning the drain, look for any wear\nthat should be addressed. Cracks in the\nconcrete should be repaired to prevent harborage.<\/p>\n\n\n\nIntroduction<\/h1>\n\n\n\n
![\"\"](\"https:\/\/blog.uvm.edu\/cwcallah\/files\/2020\/04\/Clean-Floor-1024x768.png\")
Types of Drains<\/h1>\n\n\n\n
Direct Drains<\/h2>\n\n\n\n
Air Break and Back-Flow\nPrevention<\/h3>\n\n\n\n
![\"\"](\"https:\/\/blog.uvm.edu\/cwcallah\/files\/2020\/04\/Slide2-1024x576.jpg\")
Spot or Floor Drains<\/h2>\n\n\n\n
![\"\"](\"https:\/\/blog.uvm.edu\/cwcallah\/files\/2020\/04\/Rules-of-Thumb-Pics2.jpg\")
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Trench Drains<\/h2>\n\n\n\n
![\"\"](\"https:\/\/blog.uvm.edu\/cwcallah\/files\/2020\/04\/Grate-1-1024x576.png\")
![\"\"](\"https:\/\/blog.uvm.edu\/cwcallah\/files\/2020\/04\/Rules-of-Thumb-Pics1-1.jpg\")
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![\"\"](\"https:\/\/blog.uvm.edu\/cwcallah\/files\/2020\/04\/Drain-1-1024x768.jpg\")
Trench Drain Outlets<\/h3>\n\n\n\n
![\"\"](\"https:\/\/blog.uvm.edu\/cwcallah\/files\/2020\/04\/Slide1-1024x576.jpg\")
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Drain Covers<\/h2>\n\n\n\n
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Discharge<\/h1>\n\n\n\n
Maintenance, Cleaning and\nInspection<\/h1>\n\n\n\n
![\"\"](\"http:\/\/blog.uvm.edu\/cwcallah\/files\/2020\/03\/IMG_9972-1024x575.jpg\")
Trench Drain Schematic<\/h1>\n\n\n\n
![\"\"](\"http:\/\/blog.uvm.edu\/cwcallah\/files\/2020\/04\/1215-001-C101-UVM-Drain-Conceptual-Plan-FINAL-1024x683.jpg\")
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