CLC Commercial & Retail Lighting 2 — Questions and Answers
Question 1: In a retail apparel store, which color rendering index (CRI) minimum is recommended to accurately show fabric colors?
- CRI 70
- CRI 80
- CRI 90 (Correct answer)
- CRI 60
Correct answer: CRI 90
Apparel retail requires CRI 90 or higher so customers can evaluate true fabric colors under conditions similar to natural daylight.
Question 2: What is 'accent lighting' primarily used for in a retail environment?
- General area illumination
- Highlighting merchandise to draw customer attention (Correct answer)
- Emergency egress lighting
- Task lighting for cashier stations
Correct answer: Highlighting merchandise to draw customer attention
Accent lighting directs focused beams onto featured products to create visual hierarchy and stimulate purchase intent.
Question 3: A commercial office space has an average maintained illuminance of 300 lux. According to IESNA recommendations, is this adequate for general office work?
- No, general office work requires at least 500 lux (Correct answer)
- Yes, 300 lux meets the minimum for general office tasks
- No, offices require at least 750 lux
- Yes, but only if supplemented with daylight
Correct answer: No, general office work requires at least 500 lux
IESNA recommends approximately 500 lux (50 fc) for general office tasks such as reading and computer work.
Question 4: What is the purpose of a 'layered lighting' strategy in a commercial retail space?
- To reduce the number of luminaires required
- To combine ambient, accent, and task lighting for visual interest and function (Correct answer)
- To layer multiple ceiling fixtures in a single row
- To stack lighting controls on a single dimmer circuit
Correct answer: To combine ambient, accent, and task lighting for visual interest and function
Layered lighting integrates ambient, accent, and task layers to serve multiple purposes simultaneously, improving both aesthetics and merchandising effectiveness.
Question 5: Which lamp type is most susceptible to color shift when dimmed, potentially affecting merchandise appearance in retail stores?
- LED
- Halogen
- Fluorescent T8
- Metal halide (Correct answer)
Correct answer: Metal halide
Metal halide lamps experience significant color shift and flicker when dimmed, making them unsuitable for applications requiring consistent merchandise color rendering.
Question 6: In a supermarket, what lighting technique is commonly used over produce displays to enhance the appearance of fruits and vegetables?
- Cool white LED with high CCT (6500K)
- Warm white LED with high CRI and targeted beam angles (Correct answer)
- Blue-tinted fluorescent strips
- Indirect cove lighting only
Correct answer: Warm white LED with high CRI and targeted beam angles
Warm white sources (2700–3000K) with CRI 90+ and directional beams make produce look vibrant, fresh, and appetizing to shoppers.
Question 7: What does 'uniformity ratio' describe in commercial lighting design?
- The ratio of maximum to minimum illuminance across a surface (Correct answer)
- The ratio of lumens to watts for a luminaire
- The percentage of usable light emitted downward
- The ratio of color rendering to correlated color temperature
Correct answer: The ratio of maximum to minimum illuminance across a surface
Uniformity ratio (max/min or avg/min illuminance) indicates how evenly light is distributed across a work plane or area.
CLC Commercial & Retail Lighting 2
In a retail apparel store, which color rendering index (CRI) minimum is recommended to accurately show fabric colors?