San Francisco Building Inspection Commission Codes § 1204.4

1204.4 Stairway Illumination. Stairways within dwelling units and exterior stairways serving a dwelling unit shall have an illumination level on tread runs and landings of not less than 1 footcandle (11 lux). Stairs in other occupancies shall be governed by Chapter 10.

Exception: An artificial light source is not required at the top and bottom landing, provided an artificial light source is located directly over each stairway section.

SECTION 1206 – SOUND TRANSMISSION

1206 Add the following sections:

1206.6 Definitions. The following definitions apply to Sections 1206.6 through 1206.9 of this Code. COMMUNITY NOISE EQUIVALENT LEVEL (CNEL) is a metric similar to the Ldn, except that a 5 dB adjustment is added to the equivalent continuous sound exposure level for evening hours (7 p.m. to 10 p.m.) in addition to the 10 dB nighttime adjustment used in the Ldn.

DAY-NIGHT AVERAGE SOUND LEVEL (Ldn) is the A-weighted equivalent continuous sound exposure level for a 24-hour period with a 10 dB adjustment added to sound levels occurring during nighttime hours (10 p.m. to 7 a.m.). NORMALIZED A-WEIGHTED SOUND LEVEL DIFFERENCE (Dn) means for a specified source room sound

spectrum, the difference, in decibels, between the average sound levels produced in two rooms after adjustment to the expected acoustical conditions when the receiving room under test is normally furnished.