ASHRAE 90.1 -2010, Electricity, and You
As Mississippi adopts its first energy code, many are wondering about the effects the code will have on future construction projects. Electrical engineer Shane Armour, P.E. answers those queries and more in today’s blog post on ASHRAE 90.1
The main question on everyone’s mind as Mississippi adopts ASHRAE 90.1 is what the new code will require of your building’s electrical system. The main electrical areas that affect end-users and construction costs involve both lighting and receptacle control. Adjusting lighting levels in response to incoming daylight through windows is now a requirement for many rooms in addition to occupancy sensor control of every room that does not pose a danger to health and safety. As the contribution of light from outside increases, the fixtures near the windows are required to dim and maintain as close to the same light level as possible, day or night, allowing for saving energy during the day.
Unoccupied rooms must have lights shut off automatically when no occupants are present, and the lights will only come fully back on when manually switched – automatically turning the lights on at half the design level is permitted but not required. Public areas such as corridors, restrooms, and stairwells are permitted to have the lights fully come on automatically rather than relying on manual switching.
As for receptacle control, half the receptacles in offices (private and open) and computer classrooms are now required to be switched with occupancy. This means that anything plugged in to a switched outlet will have the power cut off when someone leaves his/her office for an extended period. Computers and computer equipment are best left on the unswitched receptacles to avoid lost data and time rebooting. The switched receptacles are intended for things like desk lamps, fans, and other ancillary equipment that is not damaged by cutting power and doesn’t need to be operational at all times.
These controls are now required for all new commercial buildings in the state of Mississippi. Though the systems are designed to save energy and reduce the operational costs associated with new facilities, they do add a substantial amount to the initial construction cost of the electrical system beyond what is captured by typical historical cost trending. It is important to be aware of these increased costs when establishing a budget for any upcoming project, and when planning how much can be built within a budget.