This standard specifies the requirements for comparative testing of valve stem packing for process applications where fugitive emissions are a consideration. Packing(s) shall be suitable for use at service temperatures ?C29 ??to 538 ??(?C20 ??to 1000 ??. Factors affecting fugitive emissions performance that are considered by this standard include temperature@ pressure@ thermal cycling@ mechanical cycling@ and corrosion. This standard is not intended to replace type testing of valve assemblies or valve production testing. This standard establishes requirements and parameters for the following tests: a) fugitive emissions@ b) corrosion@ and c) packing material composition and pro a) rising stem@ and b) rotating stem. The test for fugitive emissions is based upon elements of EPA Method 21@ providing comparative values of packing performance. perties.