Plan Review: Exit Signage and Emergency Lighting in a Mercantile Building
A 12,000 sq ft retail store is being reviewed. The plan shows two means of egress, each 36 in. wide, with a 90-minute battery-backed exit sign at each door and remote-head emergency lights in the sales area. The store has a 200 A, 208Y/120 V panel. The reviewer notes: (1) the exit signs are on a general lighting circuit shared with sales-area lighting; (2) the emergency lighting unit is plugged into a receptacle on the same circuit; (3) the store has a storage mezzanine at 8 ft with no emergency lighting; (4) the panel is in a back room with no working clearance shown. The building is sprinklered.
1. Are the exit signs and emergency lighting circuits compliant with Article 700?
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No. Exit signs and emergency lighting are emergency systems and must be supplied by a circuit that is dedicated to emergency loads and that is not shared with general lighting (700.10). The exit signs must be connected ahead of the general lighting disconnect or on a separate emergency circuit so that a general lighting failure does not de-energize them. The plug-in emergency unit is not acceptable as a permanently installed emergency lighting source unless it is on a dedicated circuit and the receptacle is not switched; plug-and-cord connection is generally not permitted for emergency lighting (700.12 requires a reliable source, and cord-and-plug is not a reliable permanent connection). The reviewer should require a dedicated emergency circuit, hard-wired units, and a means to test the battery.
2. What emergency lighting is required for the mezzanine and egress paths?
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Under 700.12 and the building code referenced by 700.1, emergency illumination must cover means of egress, including aisles, corridors, and stairs, for not less than 90 minutes at the required illuminance (typically 1 fc average at floor level, with a minimum at the path of egress). A storage mezzanine at 8 ft is an occupied level with egress; it requires emergency lighting on the path to the exit and at the stair. The plan shows none, so it is deficient. Add remote heads or units at the mezzanine and at the stair, and ensure the exit path from the mezzanine to the exterior door is illuminated.
3. Evaluate the working clearance at the panel and the panel's location.
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The 200 A panel requires working space per 110.26: 30 in. wide, 36 in. deep (for 208Y/120 V to ground, Condition 2 is 3 ft), and 6.5 ft high, with the panel not located in a bathroom or over stairs. The plan shows no clearance, so the reviewer must require a dimensioned clearance. Also check that the panel is not in a clothes closet (240.24(D)) and that the working space is not used for storage. If the back room is the only location, the panel may need to be relocated or the room reconfigured. The reviewer should also verify the panel is accessible and that the 200 A service is adequate for the 12,000 sq ft store (general lighting at 3 VA/sq ft = 36 kVA plus receptacles and HVAC).