either purchased as is or can be blended on site using conventional methods well known in the art alternatively a mixture of polypropylene glycol may be formulated to create a foam which does not use flammable materials other chemical formulas may also serve to create a foam with freeze resistant properties or a lower freezing temperature this mixture may be stored in a holding tank 1 for future use when the temperature drops below freezing an electronic control unit 2 u201c ecu u201d using a temperature sensor may begin operation the ecu 2 will wait a preset amount of time before initiating line purge once the preset amount of time has been reached the ecu 2 may begin to systematically depending on quantity and size of lines purge the lines of freezable liquids by deploying aff through the lines the ecu 2 may be programmed to recognize that a line is currently in use and to wait to purge that particular line until the line is no longer being used whenever a line is being used i e a customer is washing a car the ecu 2 notes which of the lines is being used and after a preset amount of time after a line is no longer being used may proceed to purge with aff only the line or lines that were previously being used during the automatic and or systematic purging whenever a facility is used i e a customer is washing a car the ecu 2 notes which lines are being used waits a preset amount of time after a line is used then proceeds to purge with aff only the line or lines that were being used according to embodiments.