## 6.4 Interior Common Area Lighting Requirements for Multifamily Residential Buildings

There are different applicable lighting requirements for low-rise residential buildings and high-rise residential buildings. Buildings are defined as low-rise and high-rise buildings according to the following.

A low-rise residential building is a building, other than a hotel/motel, in one of the following occupancy groups:

• R-2, multifamily, with three habitable stories or less;

• R-3, single-family; or

• U-building, located on a residential site.

A high-rise residential building is a building, other than a hotel/motel, of occupancy group R-2 or R-4 with four or more habitable stories.

Interior common areas in multifamily buildings include areas such as interior hallways, lobbies, entertainment rooms, pool houses, club houses, and laundry facilities. Lighting requirements for these spaces depend on the characteristics of the buildings. Low-rise buildings are those three stories or less, and while high-rise buildings are four stories or higher.

### 6.4.1 Low-Rise Multifamily – Common Area Lighting Requirements

The residential lighting requirements apply to lighting within dwelling units in multifamily buildings. In addition to the residential lighting requirements, if the interior common area of a low-rise multifamily building is greater than 20 percent of the total floor area, the lighting in the common areas must comply with the nonresidential lighting standards.

Lighting requirements in common areas of low-rise multifamily buildings depend on the percentage of the total interior common area in each building. Buildings in which the interior common area equals 20 percent or less to the floor area have one set of requirements. Buildings whose total interior common area is greater than 20 percent of the total floor area have different requirements.

A. If The Common Area Equals 20 Percent or Less of The Total Building Floor Area

In low-rise multifamily buildings where the total interior common area in a single building is 20 percent or less of the total floor area, all permanently installed lighting in interior common areas must comply with Table 150.0-A and be controlled by occupancy sensors.

B. If The Common Area is Greater Than 20 Percent of The Total Building Floor Area

In low-rise multifamily buildings where the total interior common area in a single building is greater than 20 percent of the total floor area, permanently installed lighting in common areas must meet the applicable nonresidential lighting control and power requirements. Corridor and stairwell lighting must be controlled by occupant sensors.

The relevant nonresidential lighting requirements that apply are:

1. 110.9 – Mandatory Requirement for Lighting Controls

2. §130.0 – Lighting Systems and Equipment, and Electrical Power Distribution Systems – General

3. §130.1 – Mandatory Indoor Lighting Controls

4. §140.6 – Prescriptive Requirements for Indoor Lighting

5. §141.0 – Additions, Alterations, and Repairs to Existing Nonresidential, High-Rise Residential, and Hotel/Motel Buildings, to Existing Outdoor Lighting, and to Internally and Externally Illuminated Signs

These sections cover allowable equipment, controls requirements for various space types, allowable lighting power densities for various space types, and requirements for additions and alterations to existing buildings. More information about the nonresidential lighting requirements that apply is in Chapter 5 of the Nonresidential Compliance Manual.

In addition to meeting the applicable nonresidential lighting requirements, lighting in corridors and stairwells in these buildings must meet the following occupancy control requirements:

1. Occupancy controls must reduce stairway and corridor lighting power by at least 50 percent when the spaces are unoccupied.

2. Occupancy controls must be capable of turning stairwell and corridor lighting fully on and off from all designated paths of ingress and egress.

Example 6-12: Multifamily common areas: low rise

Question

Does the lighting for an interior common-area hallway of a low-rise residential building with a total common area of 10 percent of the total building area have to comply with the residential or nonresidential lighting requirements?

Answer

The lighting of an interior common-area hallway of any low-rise residential building with total common area of 20 percent or less of the total building area must comply with only the residential lighting requirements.

Example 6-13: Egress lighting for common areas in low-rise multifamily buildings

Question

What is the egress lighting requirement for interior common areas in low-rise multifamily buildings?

Answer

The only Energy Standards requirement is that all luminaires must be high efficacy. Refer to California Code of Regulations, Title 24, Part 2, Chapter 10, for emergency egress lighting requirements.

### 6.4.2 High-Rise Multifamily – Common Area Lighting Requirements

Lighting within residential units in high-rise multifamily or high-rise residential buildings is required to comply with the residential lighting requirements. Common areas in all high-rise multifamily buildings must meet all applicable nonresidential lighting requirements. In addition, any outdoor lighting attached to a high-rise residential building controlled from within a residential unit must meet the residential lighting requirements.

Common areas in all high-rise multifamily buildings (four stories or greater) must meet all applicable nonresidential lighting requirements in the following sections:

1. §110.9 – Mandatory Requirement for Lighting Controls.

2. §130.0 – Lighting Systems and Equipment, and Electrical Power Distribution Systems – General.

3. §130.1 – Mandatory Indoor Lighting Controls.

4. §130.4 – Lighting Control Acceptance and Installation Certificate Requirements.

5. §140.6 – Prescriptive Requirements for Indoor Lighting.

6. §141.0 – Additions, Alterations, and Repairs to Existing Nonresidential, High-Rise Residential, and Hotel/Motel Buildings, to Existing Outdoor Lighting, and to internally and Externally Illuminated Signs.

These sections cover allowable equipment, controls requirements for various space types, allowable lighting power densities for various space types, and requirements for additions and alterations to existing buildings. More information about the nonresidential lighting requirements that apply can be found in Chapter 5 of the Nonresidential Compliance Manual.

Dwelling units within high-rise multifamily buildings must comply with the residential lighting requirements.

Example 6-14: Multifamily common areas: high rise

Question

Does the lighting for an interior common-area hallway of a high rise residential building have to comply with the residential or nonresidential lighting requirements?

Answer

The lighting of an interior common-area hallway of a high-rise residential building must comply with the nonresidential lighting standards. All the lighting in common areas must comply with the nonresidential standards. Lighting inside the dwelling units must comply with the residential lighting requirements.

Hallways and stairwells are required to have partial off occupancy sensors that switch off at least half the lighting load when the hallway or stairwell is unoccupied.