Green light is the least effective for plants because they are themselves green due to the pigment Chlorophyll. Different color light helps plants achieve different goals as well. Blue light, for example, helps encourage vegetative leaf growth. Red light, when combined with blue, allows plants to flower.
Gardeners primarily use green grow lights to water, navigate the grow room, or inspect plants during the dark cycle because the green lights do not interrupt the plant's "night" period. Green light mimics moonlight, so even if a plant is aware of the light, it does not trigger photosynthesis or photoperiod hormones.
Exit Sign & Egress Lighting Codes & Standards
Larger grow rooms and buildings will need to follow code requirements. Green exit signs and egress illumination are two things to consider.
Green vs Red Exit Sign
There are several regulatory agencies out there that govern emergency lighting and sign requirements. The regulating authorities include the Occupational Safety and Health Administration (OSHA), National Fire Protection Association (NFPA), Join Commission on Accreditation of Healthcare Organization (JCAHO), International Building Code, and International Fire Code.
If the list of regulatory agencies wasn’t long enough, the local authorities having jurisdiction (AHJ) over specific exit sign requirements, such as colors. The local AHJ is responsible for monitoring and enforcing local building codes.
Although emergency exit signs with red or green lettering are generally acceptable, some states have adopted specific preferences for the color of exit signs. If you’re unsure who to reach out to regarding local emergency exit requirements, the fire marshal or inspector is a good starting point.
OSHA defines “exit route” as, “a continuous and unobstructed path of exit travel from any point within a workplace to a place of safety (including refuge areas).” An exit route includes all vertical and horizontal areas along the route and consists of the following three parts:
Exit access − The portion of an exit route that leads to an exit. An example of an exit access is a corridor on the fifth floor of an office building that leads to a two-hour fire-resistance-rated enclosed stairway (the Exit).
Exit − The portion of an exit route that is generally separated from other areas to provide a protected way of travel to the exit discharge. An example of an exit is a two-hour fire-resistance-rated enclosed stairway that leads from the fifth floor of an office building to the outside of the building.
Exit Discharge− The part of the exit route that leads directly outside or to a street, walkway, refuge area, public way, or open space with access to the outside. An example of an exit discharge is a door at the bottom of a two-hour fire-resistance-rated enclosed stairway that discharges to a place of safety outside the building.
Egress Lighting
Egress lighting is that which illuminates the travel path from any occupied space of a structure out to a public way. Emergency egress lighting is similar, except that it must remain on during a loss of normal utility power and use emergency power. Various codes outline the requirements for both, but it is the latter that often requires the most thought and planning, so let’s focus on that part for now.
The two most widely enforced codes in our region on emergency egress lighting requirements are the Life Safety Code (NFPA 101) and the International Building Code (IBC). Further reading can be found specifically in NFPA 101 Section 7.9, and IBC Section 1008.3, but in summary, these codes require the following:
“Emergency illumination shall be provided for a minimum of 1½ hours in the event of failure of normal lighting. Emergency lighting facilities shall be arranged to provide initial illumination that is not less than an average of 1 footcandle and, at any point, not less than 0.1 footcandle, measured along the path of egress at floor level. (NFPA 101 7.9.2)”
Growlite by Barron Lighting Group
Growlite is known for LED Grow Lights, but they also have a series of plant-safe, green work lights as well as exit signs for commercial buildings.
The GLE-S Green Exit Series is specifically designed to provide plant-safe Soft Green egress lighting for horticultural applications. The plant-safe, green light provides a safe means of egress while not adversely affecting plant growth during dark cycles. The GLE-S is the brightest, most visible sign in the industry in both normal and smoke-filled environments.
The GLE-GL is a purpose-built LED luminaire designed for safely lighting the dark cycle when growing short-day plants. Growlite's plant-safe soft green LEDs cannot be easily "seen" by plants allowing for critical tasks to be performed in the grow rooms during the dark cycle without the light adversely affecting the growth stage of the plant.
The GLE-GL is also available with a 90 minute battery backup to provide plant-safe egress lighting for grow facilities without disrupting critical photoperiod times.
