Final answer:
A fire door in a 2-hour rated firewall must have a minimum fire-rating of 2 hours to comply with safety standards, ensuring that the door can withstand fire and heat for the same duration as the wall.
Step-by-step explanation:
The question regarding the minimum fire-rating for a fire door in a 2-hour rated fire wall deals with building construction standards and safety requirements, typically covered under the discipline of Engineering. To ensure that the fire door is capable of withstanding the same level of fire exposure as the wall it is part of, it must match or exceed the fire-rating of the wall itself.
In this case, the correct answer would be b. 2 hours. A fire door in a 2-hour rated firewall must have a minimum fire-rating of 2 hours to comply with safety standards. This provides a uniform level of fire resistance and ensures that the door does not become a weak point in the protective barrier of the firewall during a fire emergency.
The rating ensures that in the event of a fire, the wall and its doors will resist the passage of fire and heat for a period of 2 hours, providing critical protection and allowing more time for building occupants to evacuate safely.