The WFAR water flow indicators shall be installed on system piping as designated on the drawing and/or as specified herein. Water flow indicators shall mount on any clear pipe span of the appropriate normal size, either a horizontal or vertical pipe. The indicators shall have a sensitivity in the range of 4-10 gallons per minute and a static pressure rating up to 450psi for 2"-8" (50mm thru 200mm) pipes. The indicator shall respond to water flow in the specified direction after a preset time delay that is field adjustable. The retard structure shall be a sealed mechanical pneumatic unit with visual time delay adjustment.