Ambient lighting levels in infant spaces shall be adjustable through a range of at least 10 to no more than 600 lux (approximately 1 to 60 foot candles), as measured on a horizontal plane at each bedside. Both natural and electric light sources shall have controls that allow immediate darkening of any bed position sufficient for transillumination when necessary.

Electric light sources shall have a color rendering index (CRI)⁸ of no less than 80, and a gamut area index (GAI)⁹ of no less than 80 and no greater than 100. The optical reflectors in the luminaires (light fixture) shall have a neutral finish so that the color rendering properties of the light source are maintained. The sources shall avoid unnecessary ultraviolet or infrared radiation by the use of appropriate lamps, lens, or filters⁵.

No direct view of the electric light source or sun shall be permitted in the infant space (as described in Standard 5): this does not exclude direct procedure lighting, as described in Standard 23. Any lighting used outside the infant care area shall be located so as to avoid any infant's direct line of sight to the fixture.

The electric light sources that are supplied by 60 Hz alternating current shall not flicker more than a common 40 W incandescent light source. Specifically, the frequency and the depth of the light modulation produced by the source shall be no less than 120 Hz and no more than 13%, respectively¹⁰.

Lighting fixtures shall be easily cleaned.

Interpretation: Substantial flexibility in lighting levels is required by this standard so that the disparate needs of infants at various stages of development and at various times of day can be accommodated, as well as the needs of caregivers. In very preterm infants, there has been no demonstrable benefit to exposure to light. After 28 weeks gestation, there is some evidence that diurnally-cycled lighting has potential benefit to the infant11. Caregivers benefit from moderate levels of ambient light in order to perform tasks and maintain wakefulness.

Control of illumination should be accessible to staff and families, and capable of adjustment across the recommended range of lighting levels. Use of multiple light switches to allow different levels of illumination is one method helpful in this regard, but can pose serious difficulties when rapid darkening of the room is required to permit transillumination, so a master switch should also be provided.

Perception of skin tones is critical in the NICU; light sources that meet the CRI and GA values identified above provide accurate skin-tone recognition. Light sources should be as free as possible of glare or veiling reflections. When the light sources to be used are linear fluorescent lamps, these color criteria can be met by using lamps that carry the color designation "RE80".