If a room is 54 ft by 54 ft, a single strobe rated 110 cd would meet NFPA 72 requirements. True or False?

If a room is 54 ft by 54 ft, a single strobe rated 110 cd would meet NFPA 72 requirements. True or False?

• A. True
• B. False
• C. Only if additional strobe
• D. Only if placed on ceiling

Answer: (A)

NFPA 72 requires the visible signaling devices to provide enough brightness so that occupants can notice the flash from anywhere in the space. The rating chosen for a strobe matters because the required intensity is based on room dimensions and mounting height, with tables in the code indicating what candela is needed to achieve the necessary visibility at the farthest points. In a square room that is 54 ft by 54 ft, a strobe rated at 110 cd, when mounted on the ceiling near the center, typically provides sufficient visibility to the far corners (about 38 ft away from center). That placement yields the required coverage without needing extra devices, so the statement is true. If the strobe isn’t placed properly—such as being wall-mounted or obstructed—visibility could fall short and additional strobes might be needed.

NFPA 72 requires the visible signaling devices to provide enough brightness so that occupants can notice the flash from anywhere in the space. The rating chosen for a strobe matters because the required intensity is based on room dimensions and mounting height, with tables in the code indicating what candela is needed to achieve the necessary visibility at the farthest points. In a square room that is 54 ft by 54 ft, a strobe rated at 110 cd, when mounted on the ceiling near the center, typically provides sufficient visibility to the far corners (about 38 ft away from center). That placement yields the required coverage without needing extra devices, so the statement is true. If the strobe isn’t placed properly—such as being wall-mounted or obstructed—visibility could fall short and additional strobes might be needed.