In residential and commercial buildings, most components of electrical installations are hidden from sight - only elements like lighting fixtures and receptacles are exposed, since their function requires it. The role of electrical systems in building interiors is much more evident in industrial settings, where there are no dropped ceilings or dry walls to hide conduit, junction boxes and other accessories.
Practically all building systems have at least one electrical component, even if the main energy input is not electricity. For example, space heating systems rely on motor-driven fans to distribute air, and gas-fired equipment in commercial kitchens uses electronic controls. Electricity is normally associated with lighting fixtures, power outlets and air conditioners, but its coverage is much broader!
Electricity is the fastest and cheapest energy transmission method known by modern society, but this also makes it dangerous. If a high-magnitude current is not interrupted quickly, it can easily start a fire.
The mechanical systems for residential projects are generally straightforward by in large. With commercial systems, however, the complexity increases ten-fold. Take for instance, a residential kitchen versus a commercial kitchen. Of the two, a commercial kitchen produces considerably more food, and depending on the manner in which it is prepared (i.e. grilling or frying), it will also generate significantly more grease and smoke.
At home, foods prepared in a similar manner are often cooked outdoors to eliminate such hazards. In a commercial kitchen, food preparation is primarily performed indoors, intended to be served to those dining in a neighboring room – from restaurant patrons to residents of a senior living facility. It is paramount that the smoke and grease generated from these activities remain within the kitchen area and not enter the dining room. If these elements were to expand beyond the kitchen, it would create, at best, an unpleasant experience for diners, and at worst, health concerns for those sensitive to contaminates in the air.
To combat this, a commercial kitchen exhaust hood system must be in place. These commercial grade systems are far more complex than the typical range hood or combination microwave/hood with a 3-speed fan, light and small mesh grease filter, commonly found in most homes. Commercial kitchen exhaust hood systems also must meet stringent mechanical code requirements such as the size of the kitchen hood, the amount of air needed to be exhausted by the fan, as well as the materials of which these items are constructed and how and when the system needs to operate.
Electrical design is as equally complex. In both residential and commercial projects, engineers must first analyze the building’s power requirements before specifying the electrical installation required to supply the power at the correct voltage. From there, the similarities diverge.
Take again, the example of the commercial kitchen. Local and state health department codes often require precise lighting levels in certain areas throughout a commercial kitchen to ensure that food preparation and clean-up is performed under adequate lighting. For instance, North Carolina code calls for a 50 foot candle — the base measurement for describing luminous intensity — for those areas.
Code also requires that electric designers use shatter-proof or shielded light bulbs in a commercial kitchen’s food preparation, storage, and display areas. Given the volume of food prepared and the number of employees needed to adequately staff a commercial kitchen, the kitchen environment can quickly become hectic, giving rise to potentially dangerous situations. For example, harried employees could accidentally hit and shatter the bulbs, injuring themselves or contaminating patrons’ food with shards of glass. The bulbs could also easily fail, forcing employees to work with sharp kitchen utensils in insufficient light.