This document contains guidelines for the installation of roof mounted outdoor air-conditioner equipment as developed and agreed upon by the Air-Conditioning, Heating, & Refrigeration Institute (AHRI) and Air Conditioning Contractor's National Association, Inc. (SMACNA). The purpose of these Guidelines which cover curb and roof penetrations and sealings is to set forth good construction practices.The Guidelines are just that—guidelines—and are not standards, warranties or certifications.

The information contained in these Guidelines should serve as a supplement to the unit manufacturer's specific installation instructions. The precise steps to be taken with respect to a specific curb, roof penetration or sealing may vary according to particular circumstances, job conditions and manufacturer's specifications. In all cases, the necessary installation work should be done by and under the supervision of skilled and qualified personnel.

These Guidelines cover instructions on the interface between the roof and the location at which the unit, piping, electrical wiring or sheet metal ductwork pass through the roof. For more detailed design information, see the SMACNA Architectural Sheet Metal Manual, HVAC Duct Construction Standards, and the National Electrical Code. These documents were the source for many of the recommendations made in these Guidelines. No changes in these AHRI - SMACNA Guidelines shall be made without the approval of AHRI and SMACNA.