There is no standard way to connect air that I know of. Service companies that do this in my area carry a huge array of fittings. I do my own and here's how I do it. First, I remove my BF preventer and store it inside to avoid the possibility of any residual moisture freezing in it. Is this necessary? I don't truly know, but a new BF like I have costs close to $150, and I feel storing it out of the cold is cheap and easy insurance. The water shuts off with a stop and waste valve 5 feet underground right after the tee in the water supply out of the meter, so draining that side is automatic. The BF connects to both the supply side and to the manifold side with 1" copper unions, so pulling the BF is pretty quick and easy. I made an air hose adapter with a quick connector for the air hose, a ball valve, and 1/2 of a copper union to replace the BF. When I blow the lines, I close the ball valve while the compressor reloads. Then I manually open one zone, open the ball valve, and blow that zone. I blow two 70 gallon tanks of air through each zone. This works well for me. Those petcocks on your BF are for the test instruments to verify your BF is performing correctly. In my city, it is required that all BF devices be tested by a licensed, certified tester each spring. Hope this helps.