When the PSS is in RF Power Permit the hall is considered an ``exclusion area''. Delivery of RF power is permitted, but beam delivery is not. Reaching this state requires that the hall has passed through the controlled access state and that no one is left inside the hall. This is usually a temporary state bridging the transition from the Controlled Access to the Beam Permit state. Once the Personnel Safety System reads ``Power Permit'', a steady klaxon sounds in the hall. If you are in the hall when this klaxon sounds, press the emergency safe button on the nearest run/safe box and immediately exit the hall. The hall entrance gates are locked at this time, but there is an emergency exit button at each gate which will allow you to exit. A four-minute delay is built in between the transition from RF Power Permit to Beam Permit.