What is required of a certificate holder during personal supervision?

During personal supervision, the certificate holder must be physically present on the premises. This requirement ensures that the certificate holder can immediately oversee, respond to, and manage any urgent situations that may arise concerning the standpipe system. Being on-site allows for direct supervision and efficient communication with staff or emergency responders, ensuring safety protocols are followed effectively.

The other choices indicate circumstances that would undermine proper oversight and accountability, which are critical components of maintaining operational readiness and safety of the standpipe system. If the holder were allowed to work off-site or only be available via phone, it could result in delays in decision-making or response to emergencies. Similarly, supervising multiple locations at once would partition attention, potentially compromising safety standards. Thus, having the certificate holder present on the premises is essential for effective management and safety.