Which commissioning stages should the client actually attend?

Three commissioning stages reward the client's time on site. The rest can be witnessed by an independent commissioning manager and signed off on paper.

Stages worth being in the room for

• Functional Performance Tests on the converged HMI — the operator-facing view, not the individual subsystem panels.
• Concurrent maintenance drills on Tier IV estates — the resilience story under live conditions.
• Alarm rationalisation review — where the alarm queue the estates team will live with is finalised.

Skipping any of these means relying on documentation that may not match what was actually delivered. The 30 minutes of presence is one of the highest-leverage commitments on the project.