SIR and CAF
Both Surface Insulation Resistance (SIR) and Conductive [Cathodic] Anodic Filamentation (CAF) test techniques are relatively new methods to determine product reliability in the field.
SIR, although in use for over 40 years for materials characterisation, has now been evolved into an accurate and quantitative method to predict circuit reliability from an electro-chemical standpoint. It is now being used to characterise the manufacturing (assembly) process. It is carried out on a representative coupon (test vehicle)
under temperature and humidity to determine if there are any adverse surface insulation reactions that would affect reliability long term.
Curiously, science research carried out by NPL, et al, proved that lower voltage and narrower conductor spacing increased the susceptibility of electro-chemical failure. AutoSIR can measure all of these effects at levels down to 1014 Ohms.
CAF is a reliability issue involving sub-surface dendrites. As such it is used to determine the manufactured quality, and likely reliability, of circuit boards. AutoSIR is able to measure these influences accurately and reliably.