I came across this bit of text that gives some definitions.
Zone 3 Technical Rescue Manual
The pdf is a good read.
Critical Point Test:
A Critical Point Test requires that rope system in its entirety is looked at to
insure that the failure of any one part of the rope system, either human or
equipment, will not result in a total system failure (dominoe effect). A Critical
Point Test can be performed by asking “What if” type of questions in regard to the rope system, such as “What would happen if the Track Line failed”, or
“What would happen if the Main Line anchor failed”.
The passing of a Whistle Test means that if in theory at any point a whistle
were blown which signals all personnel to “let go” of the rope or equipment
that they are operating, nothing catastrophic will occur to the live load that is
depending on the rope systems for their safety. Some examples of
equipment that allow passing of a Whistle Test are the use of a Belay Line
and Prusiks that will capture the load if the team operating the Main Line
slips and lets go of the Main Line while hauling up the live load, or a tandem
Prusik on a Load Release Hitch situated towards the load on a Control Line
lowering operation utilizing a Brake Bar Rack in the event a Track Line fails
and imparts an impact load to the Control Line.
NZLSAR (New Zeland guys) have a great definition of the Critical Point Test;
I like this because it lets common sense, risk vs. benefit and our skills as technical rescuers overcome a noted weak point in the system; if you are weary of an anchor for example you can add redundancy (my least favorite), back up the anchor (such as a tieback) or accept the risk to perform the mission.Quote:
The critical point test examines whether or not a failure of any one component would result in a total system failure with ensuing catastrophic outcome. If critical points are found, they should be analysed to see if they need to be eliminated by a redundant component, backed up or accepted.
What is doesn't mean is that since you have a bombproof anchor, that you would assume the anchor would fail and need a redundancy. Or that you need two of everything. Trust in your equipment, the human factor is always the weak link in the system anyhow.