  The Herschel SPIRE FTS Spectral Feature Finder (FF) detects significant
spectral features within SPIRE spectra and employs two routines, and external
references, to estimate source radial velocity. The first routine is based on
the identification of rotational CO emission, the second cross-correlates
detected features with a line template containing most of the characteristic
lines in typical far infra-red observations. In this paper, we outline and
validate these routines, summarise the results as they pertain to the FF, and
comment on how external references were incorporated.
