SVR was part of an earlier version of UL 1449 Edition and is no longer used in the UL 1449 standard. The SVR was replaced by VPR.

VPR is part of the UL 1449 3rd Edition and is the clamping performance data for SPDs. Each SPD mode is subjected to a 6kV/3kA combination surge wave and its measured clamping value is rounded up to the nearest value based on table 63.1 from UL 1449 3rd Edition.