‘High bay’ and ‘low bay’ are common descriptors for overhead lighting with industrial or commercial applications. Though it is not a technical term with a fixed definition, the difference is generally understood within the lighting industry and important to know when it comes to choosing a solution for your project.
High Bay vs. Low Bay Lighting
The primary difference between high and low bay lighting is the mounting height for which the luminaire or light is designed. Mounting height refers to the vertical distance between the light and the base of its fixture; or, in the case of a hanging or wall-mounted luminaire, the distance between the ground and the light.
High bay lighting refers to luminaires designed to be mounted at a vertical height of 20 feet or greater; low bay lighting is intended for heights of between 12 or 20 feet.
When customers ask for high bay lighting, they are typically looking to illuminate large, open rooms with great vertical and horizontal space, or vast outdoor spaces. High bay luminaires are built to sufficient light to illuminate a large surface area without the aid of natural light.
Common indoor applications for high bay lighting include:
- Factory warehouses
- Department stores
- Covered sports stadiums
Common outdoor applications for high bay lighting include:
- Sports fields
- Parking lots
- Public parks
To determine whether high or low bay lighting better suits your project, measure the distance between the floor and the ceiling (or in the case of an outdoor project, the ground and the intended mounting height). For heights exceeding 20 ft., it’s likely that high bay lighting will be an ideal solution.
Types of High Bay Lighting
The four main types of luminaires used for high bay lighting are:
- Metal Halide
- High-pressure sodium
In terms of pure illuminance and brightness, metal halides are usually the most powerful type of high bay lighting available. Metal halide lighting is often used to illuminate outdoor sports stadiums and very large warehouses. Unlike high-pressure sodium lights, metal halides provide good colour rendering, meaning they portray the colours of objects accurately compared to natural light; this is important for major games and other events that will be filmed and broadcasted.
The biggest downside to metal halides is the fact that they must ‘warm up’ before they reach their full illuminance, which can take up to half an hour.
High-pressure sodium and fluorescent lighting are types of gas luminaire, producing light inside of a transparent, gas-filled tube sealed at either end by electrodes. These luminaires are powerful and affordable, but they provide poor colour rendering and require a ballast to stabilize the light. Fluorescent lights contain mercury, which means they must be disposed of safely and carry higher maintenance costs.
Light emitting diodes or LED luminaires are highly efficient and durable, generating light in using solid-state materials inside of a microchip. This future-proof technology can be made even more efficient using automated lighting solutions for high bay LEDs, such as an energy management system. They provide good colour rendering and impressive illuminance, considering they come in a small package.
One of the chief concerns in choosing high bay lighting is maintenance. Since high bay luminaires are mounted at great heights, replacing and repairing them can be expensive in dangerous, requiring workers to use scaffolding, catwalks or hydraulic lifts in order to reach them. This makes the durability of LED luminaires appealing, and many companies are beginning to replace their existing gas luminaires with lighting solutions for high bay LEDS.