By: Nathan Short, P.E. and Jonathon Pfantz, P.E.
Adjustments to the International Energy Conservation Code (IECC) have been made in efforts to achieve significant energy savings within the built environment. In recent months, several local jurisdictions such as Scottsdale and Chandler, have begun to adopt the 2015 IECC.
In regards to electrical power and lighting systems, new energy efficiency standards now apply. For example, automatic dimming controls are required in daylight areas adjacent to windows and below skylights. The associated energy savings will help decrease a building’s overall electrical needs while reducing the owner’s utility bill. There is also a decrease in the lighting power density requirements and the code now encourage the use of higher efficacy light fixtures (e.g. LED). More efficient design practices are encouraged in efforts to maintain light illumination levels in spaces all while meeting the allowed wattage of light fixtures.
There are also new mandates for automatic shutoff of interior and exterior lighting. Occupancy sensors are required in more space types and, where not required, a time based control with multiple schedules and override switches must be implemented. The dimming control and automatic response, based on the amount of available daylight for exterior lighting, will reduce energy use and unnecessarily illuminating open parking lots during hours of infrequent or non-use. Additional provisions include requirements for electrical transformer and motor efficiency, regenerative drives in escalators, and expanded requirements for existing or altered buildings.
Within the building mechanical systems section, several mandatory requirements have been modified and several new sections have been included. Minimum efficiency requirements of packaged AC equipment, chillers and cooling towers have increased, however not all equipment sizes have been impacted. Additionally, energy recovery units requirements have been modified based on the system operating hours per year; there are different minimum airflow requirements based on whether the system operates greater than or less than 8,000 hours per year. Ventilation systems that operate more than 8,000 hours per year are more likely to require energy recovery equipment over systems that operate less than 8,000 hours per year.
New mandatory requirements include the addition of;
zone isolation areas (zones that exceed 25,000 square feet or span more than one floor)
- must operate non-simultaneously
- shall be provided with isolation devices that automatically shut down airflow to and from isolation area
economizer fault detection and diagnostics
- direct expansion and VRF units that are provided with economizers to be installed with fault detection and diagnostics
- additional system sensors and system status points
- shall be capable of detecting faults and triggering alarms for building maintenance staff
enclosed parking garage ventilation controls
- contaminant sensing devices (such as CO sensors) that modulate fans to provide 50% or less airflow than design or operate fans intermittently 20% of the occupied time to maintain acceptable contaminant levels within a parking garage
kitchen exhaust systems
- replacement air for exhaust hoods and documents that hood exhaust rates that exceed 5,000 CFM will require factory-built commercial exhaust hoods.
computer room air conditioning units
New efficiency requirements:
- units that are installed for computer rooms must have more than five tons of sensible cooling