W Witness point
Witness point · Inspección y ensayos · ISO 1101 + ASME Y14.5
Example in plan
How to interpret it
On the drawing, “Witness point at pressure test · 48 h notice” states a witness point requirement.
What controls
Point in the process at which the customer is entitled to be present during an inspection or test, but which does not block production if, after notice within the agreed period, the customer decides not to attend. It is a process requirement with a notification effect, not a blocking one. The inspection is carried out regardless and the result is recorded; what changes depending on whether the customer attends is who signs as witness.
How to verify
The relevant test or measurement, performed and recorded as for any other check, with the addition of an attendance record when the customer is present. The record must include the notification sent, its date and the response received. If the customer attends, the report usually carries their signature in addition to that of the quality manager.
Common mistakes when interpreting it
- Treating it as a hold point and stopping production unnecessarily.
- Performing the test without having sent the notification, which is what makes it valid to continue without the customer.
- Not keeping a written record of the notification and the date it was sent.
How to get it in the workshop / if it comes out of tolerance
The key is the notification: notice must be given with the agreed lead time and that notice must be documented, because it is what allows work to proceed if the customer does not show up. Do not turn it into a hold point on your own initiative, nor the other way round. Have the test ready for the committed time: a customer who has traveled to the shop and a machine that is not ready is a serious relationship problem.
If the customer does not respond to the notice, the test is performed and documented with the notification as backup. If they turn up late and the test has already been done, they are given the record; repeat it only if the contract requires it. If the result is unfavorable with the customer present, document it as is: tampering with a witnessed test is a far bigger problem than the failure itself.
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