The CSA created a manual CAN/CSA-B64 to provide standards for the selection and installation of backflow prevention devices. CSA classifies facilities by Sever, Moderate and low risk. Sever risk facilities must install a reduced pressure (RP) backflow preventer. Moderate risk requires a minimum of a dual check valve assembly. Examples of sever risk facilities include: Agriculture facilities, Industrial premise, Automotive repair, Food processing plants, carwashes, Gas stations, laundromats and many more. Refer to CAN/CSA-B64 for the entire list.