1) If the acronym is PST (capitals) then the full phrase would be Partial Stroke Testing.
2) The question is whether or not a particular facility is needed, therefore you need an article: "Please confirm that A PST facility......."
3) Valves? Something medical? Heart valves? If so, you do not provide a whole facility for just one person's medical problem. If this relates to one individual case, then I would say "Please confirm that a Partial Stroke Test is required (means the same as "needs to be provided") for/on these valves."