Current Status Not Enrolled Price Free Get Started Login to Enroll NFPA 291 – Water Flow Testing and Marking for Hydrants Length: 1 Hour This course will discuss the recommended practices detailed in the 2016 edition of NFPA 291 to perform flow tests on hydrants and mark hydrants based on available fire flows.. NFPA 291 – Water Flow Testing and Marking for Hydrants Course Content NFPA 291 – Water Flow Testing and Marking for Hydrants