{"id":2162,"date":"2019-05-20T12:29:09","date_gmt":"2019-05-20T16:29:09","guid":{"rendered":"http:\/\/blog.uvm.edu\/cwcallah\/?p=2162"},"modified":"2019-10-15T10:59:50","modified_gmt":"2019-10-15T14:59:50","slug":"backflow-prevention-for-produce-farms","status":"publish","type":"post","link":"https:\/\/blog.uvm.edu\/cwcallah\/2019\/05\/20\/backflow-prevention-for-produce-farms\/","title":{"rendered":"Backflow Prevention for Produce Farms"},"content":{"rendered":"\r\n
\"\"<\/a>
Check valves are one of several ways to prevent backflow.<\/figcaption><\/figure>\r\n

The intentional, directional, and reliable flow <\/strong>of water is important to ensure agricultural water is \u201csafe and of adequate sanitary quality\u201d.<\/p>\r\n

This post provides information on the importance of backflow prevention and some common practices that help mitigate the risk of backflow. You can also view presentation slides<\/a> and a recorded webinar<\/a> on this topic that were provided for the May 2019 Produce Safety Alliance Educators Call.<\/p>\r\n

\"\"<\/a>PDF Download of this information: Backflow Prevention Factsheet<\/a><\/p>\r\n

<\/p>\r\n

Regulatory and Training Context<\/h1>\r\n\r\n\r\n\r\n

There are at least three places in the FSMA Produce Safety Rule<\/a> (PSR) that are relevant and two in the Produce Safety Alliance<\/a> (PSA) National Curriculum<\/a> (emphasis<\/span> added):<\/p>\r\n\r\n\r\n\r\n

FSMA PSR \u00a7112.41<\/p>\r\n

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What requirements apply to the quality of agricultural water? All agricultural water must be safe and of adequate sanitary quality<\/span> for its intended use.<\/p>\r\n<\/blockquote>\r\n

FSMA PSR \u00a7112.42:<\/p>\r\n

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What requirements apply to my agricultural water sources, water distribution system, and pooling of water?<\/p>\r\n

(a) \u2026 you must inspect all of your agricultural water systems\u2026 including consideration of the following: \u2026<\/p>\r\n

(5) The likelihood of introduction of known or reasonably foreseeable hazards to agricultural water<\/span> by another user of agricultural water before the water reaches your covered farm.<\/p>\r\n

(b) You must adequately maintain all agricultural water distribution systems \u2026 to prevent the water distribution system from being a source of contamination to covered produce, food contact surfaces, areas used for a covered activity, or water sources<\/span>\u2026<\/p>\r\n

(c) You must adequately maintain all agricultural water sources\u2026 Such maintenance includes regularly inspecting each source to identify any conditions that are reasonably likely to introduce known or reasonably foreseeable hazards into or onto covered produce or food contact surfaces; correcting any significant deficiencies (e.g., \u2026 and control of cross-connections<\/span>); and keeping the source free of \u2026 other possible sources of contamination \u2026<\/p>\r\n

(d) \u2026 implement measures reasonably necessary to reduce the potential for contamination<\/span> \u2026 as a result of contact of covered produce<\/span> with pooled water. \u2026<\/p>\r\n<\/blockquote>\r\n

FSMA PSR \u00a7112.133:<\/p>\r\n

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What requirements apply to plumbing?<\/p>\r\n

The plumbing must be of an adequate size and design and be adequately installed and maintained to:<\/p>\r\n

(a) Distribute water under pressure as needed, in sufficient quantities, in all areas where used for covered activities, for sanitary operations, or for hand-washing and toilet facilities;<\/p>\r\n

(b) Properly convey sewage and liquid disposable waste;<\/p>\r\n

(c) Avoid being a source of contamination to covered produce, food contact surfaces, areas used for a covered activity, or agricultural water sources; and<\/p>\r\n

(d) Not allow backflow from, or cross connection between, piping systems<\/span> that discharge waste water or sewage and piping systems that carry water used for a covered activity, for sanitary operations, or for use in hand-washing facilities.<\/p>\r\n<\/blockquote>\r\n

PSA Module 5.1 – Slide #12<\/p>\r\n

\"\"<\/a><\/p>\r\n

PSA Module 5.2 – Slide #17<\/p>\r\n

\"\"<\/a><\/p>\r\n

Flow of Water<\/h1>\r\n

When thinking about controlling water flow, it may be helpful to remember some basic things about water.<\/p>\r\n

    \r\n
  • Water flows downhill <\/b>due to gravity and\/or along the path of least resistance<\/b> (which could be sideways). <\/b><\/li>\r\n
  • Water flows from high to low pressure. <\/b>We use pumps to increase the pressure in one place so that flow goes in a certain direction. There are times when the pressure difference shifts due to suction or siphoning. A fire hydrant draw is a good example<\/a>.<\/li>\r\n
  • Water flows in pipe <\/b>and tube. <\/b>This helps to direct flow in only certain directions or along certain paths.\u00a0 But it also “connects” different locations.\u00a0 This can lead to “cross connection” between a relatively dirty or hazardous use and a food contact surface.<\/li>\r\n
  • We control the flow of water with valves.<\/b> Most are manual or electronic solenoid valves.\u00a0 But, we also use “check” valves as passive, automatic flow controls.\u00a0 They bias flow in only one direction.<\/li>\r\n<\/ul>\r\n

    Introduction to Backflow<\/h1>\r\n

    Backflow<\/b> is when water (and anything in it) travels in the \u201cwrong\u201d direction or a direction other than the intended one.<\/p>\r\n

    Backflow Prevention <\/b>is taking steps to ensure water flow is in the intended direction or along a path that minimizes produce safety risk due to cross-connection and cross-contamination.<\/p>\r\n

    Backflow is typically prevented by<\/p>\r\n

      \r\n
    • Obstructing flow in one direction (using a check valve, foot valve, etc), or<\/li>\r\n
    • Providing an easier flow path in a different direction that results in lower risk (using air gaps, floor sinks, etc.)<\/li>\r\n<\/ul>\r\n

      The Charleston, SC Water Department offers a great video<\/a> summarizing the ways backflow can happen and why it can be a problem.<\/p>\r\n