A refrigeration machinery room requires a fire-rated separation from the remainder of the occupancy unless sprinklered. The required separation is for how many hours?

• A. 1/2 hour
• B. 2 hours
• C. 3 hours
• D. 1 hour

Answer: (D)

This question tests how compartmentation is used to contain fires in mechanical spaces and how automatic sprinklers affect that requirement. A refrigeration machinery room houses refrigerant equipment and oils that can fuel a fire, so it needs a fire-rated barrier to keep the rest of the building safe if there’s no active suppression. When there’s no sprinkler system, the barrier must resist fire for one hour, providing time for evacuation and for responders to act while the room stays compartmentalized. If sprinklers are present, the additional fire separation isn’t required, which is why the correct rating for the un-sprinklered scenario is one hour. The other ratings are not standard for this situation.