The lighting within a space is critical to ensure a safe and productive work environment. This is especially important when designing lighting for hospitals, and specifically the pharmacies within them. Lighting should be provided at an appropriate level for the task being performed as well as uniform to ensure there is minimal light contrast. While it is easy to overlook pharmacy lighting, it is just as important as lighting for an operating room, with some big challenges. The whole engineering team must be coordinated throughout the ceiling and the productivity level of the workers could depend heavily on the lighting in the room.
The coordination between engineering disciplines begins with lighting and HVAC equipment, with many different pieces of equipment needing ductwork run. Between Fan Filter Units, diffusers, and piping, the ceiling grid is left with a select few places for lights. However, lighting needs to be placed evenly through a space in order to achieve a high-quality uniformity ratio within the space (2:1 average to min ratio). Having an average to minimum ratio of close to 1:1 ensures equal light distribution throughout the space with no visible dark points. The farther the ratio gets from 1:1 means the dark spots will be significantly more visible against the brighter portions of the room. It can be challenging to achieve a high illumination level while still having a good uniformity ratio but many light fixtures for these spaces come in high output options with a brighter lumen package to throw more light so you can use less light fixtures while still maintaining proper light levels and ratios. Once all the lights are placed, sprinklers also must be coordinated with lights and HVAC equipment which have their own code restrictions to follow about spacing and coverage. Most traditional light designs within a pharmacy use an Ingress-Protection (IP) rated, recessed, 2x2 LED fixture that occupies its own ceiling grid tile. IP ratings define how sealed the enclosed fixture is from dirt, moisture, and other foreign elements. Each rating is for various enclosures and applications because not all areas require the same amount of protection. However, if space is very limited, an alternative product is a combination air handling light fixture that provides a two-in-one option to minimize ceiling tiles. Whichever concept is chosen, the ideal design is to use the least amount of space possible while maintaining a high foot-candle level. When looking at the ideal lighting levels for spaces, the Illumination Engineering Society of North America (IESNA) provides the standards to design towards. The IESNA lighting handbook recommends a well illuminated area in the pharmacy and designing the average foot-candle level for the pharmacy to be about 100fc ensures accuracy on the precision tasks required within the space. The task light level needs to be higher due to labeling that is very small or fast dispensing of drugs in order to ensure high visual accuracy.
While it is important to maintain a high foot-candle level throughout the pharmacy, the color temperature is also extremely important for productivity. Most lighting in pharmacies are blue-rich temperatures, between 4000-5000K. Studies have shown this color temperature range increases productivity as it improves alertness and focus, but only for daytime workers. In fact, blue-rich color temperatures can be extremely detrimental to night shift workers and their natural circadian rhythm. To combat this, a circadian rhythm controller can be installed to increase the blue-rich light during the day while minimizing it during the nighttime in order to get maximum productivity out of all workers at all times of the day. The downside to this is the rather high up-front cost of the lighting and controls, but the long-term savings of productivity and an increase in well-being for everyone can return those initial costs. If circadian rhythm is not used, a dimmer switch with an overhead occupancy sensor can be implemented so all workers, especially the night work staff, can reduce the light level in order to be their most productive self.
While there are other factors that come into consideration with pharmacy lighting, achieving high light levels in minimal space and productivity versus cost will always be challenging.
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Brian Drouse, EIT