Unfortunately this past freeze Houston homeowners had the misfortune of finding there sprinkler backflow broken from the freezing temperatures. We should be ok from now till next winter (if we get one for 2018). Investing less than $10.00 in material will save you the headache and expense of a future repair. The picture on the left was properly insulated. Notice the brass body and the top canopy(bell) are also insulated as well. Picture on the right, well you probably have the idea of what the end results for this unfortunate backflow.