According to NFPA 101, Life Safety Code, the maximum length of a dead-end corridor in a new mercantile occupancy is generally limited to 20 ft (6.1 m). However, the code provides an exception for buildings that are protected throughout by a supervised automatic sprinkler system installed in accordance with NFPA 13. In such cases, the maximum permitted length of the dead-end corridor is extended to 50 ft (15 m). This allowance is based on the increased level of life safety provided by the automatic suppression system, which controls fire growth and provides occupants with more time to egress.

A. This is the maximum length for dead-end corridors in new mercantile occupancies that are not protected by a supervised automatic sprinkler system.

C. This length is not specified in NFPA 101 for dead-end corridors under any condition for new mercantile occupancies.

D. This length is not specified in NFPA 101 for dead-end corridors under any condition for new mercantile occupancies.

1. NFPA 101®, Life Safety Code®, 2021 Edition.

Chapter 36, New Mercantile Occupancies, Section 36.2.5.4, Dead-End Corridors.

36.2.5.4.1: "In buildings protected throughout by a supervised automatic sprinkler system in accordance with Section 9.7, the dead-end corridor length shall not exceed 50 ft (15 m)."

This section explicitly states the 50 ft limit for sprinklered conditions, directly supporting the correct answer. The base limit of 20 ft is found in the parent section 36.2.5.4, which explains why option A is incorrect.