How many lamps of equal wattage are required for adequate emergency lighting?

For adequate emergency lighting, the requirement for two lamps of equal wattage is based on ensuring redundancy and safety. The rationale behind needing two lamps is to maintain adequate illumination in case one lamp fails. This redundancy is essential for compliance with safety codes and standards that govern emergency lighting systems.

Having two lamps ensures that if one lamp experiences a malfunction or burns out, the other lamp will continue to provide necessary illumination, thereby enhancing safety for occupants during an emergency situation when reliable lighting is crucial. The goal is to ensure that pathways, exits, and critical areas remain adequately lit to facilitate safe evacuation or to assist in locating emergency supplies.

Selecting a configuration with only one lamp does not provide the necessary reliability since its failure would leave the area completely dark. More than two lamps would also exceed the minimum requirement, which is typically not necessary for standard emergency lighting situations. Therefore, two lamps strike the right balance between sufficient coverage and practical redundancy.