Where new large, complex or critical control systems are to be installed in an existing building, determine if the existing control air source is adequate and of acceptable quality. If there is doubt, provide a new control air compressor, with cross connection to existing. Specify copper for all control air tubing in exposed areas, and in concealed areas where elevated temperatures might damage plastic air tubing. Do not allow short radius bends. Do not allow plastic caps on copper tubing.
Properly space supports to prevent sag.
Tubing installed in plenums shall be type FR only. Pressure test control tubing at 35 psi.