Updated energy code will have big impact
The NJ State Department of Community Affairs (DCA) formally adopted the 2015 International Energy Conservation Code (IECC) on September 21, 2015. The six month grace period expired on March 21, 2016, so all building projects filing for permits as of that date must meet the new requirements. These new codes will have some significant impact on the design of new buildings and major renovations of existing buildings.
The IECC contains separate provisions for commercial buildings and low-rise residential buildings. The commercial requirements are based on ANSI/ASHRAE/IES Standard 90.1 – 2013. The previous code was based on the 2007 edition, so this adoption also includes changes that occurred in the 2010 edition, which were more radical than the more recent edition. The estimated savings for the most recent revisions is 8.7%, whereas the 2010 edition represented a 23.4% savings over 2007. So combined we should expect cost savings of about 30%.There are some slight differences between South Jersey (Climate Zone 4) and North Jersey (Climate Zone 5), but both zones have changes that impact the thermal envelope, HVAC systems, lighting and lighting controls. For commercial buildings, the building envelope now requires R-30 insulation on a flat roof, and R-49 insulation in an attic. Vertical Glazing maximum U values decreased depending on the type between 0.35 and 0.50; and the maximum Solar Heat Gain Coefficient is 0.40. The maximum U values for skylights depend on the type and the percentage of roof area. The vertical glazing is still limited to 40% of the gross wall area. Buildings exceeding this or any other prescriptive requirement must perform an energy model to demonstrate that the proposed design uses no more energy on an annual basis than a building designed according to the prescriptive requirements. For buildings seeking LEED Certification, an energy model is required to demonstrate that the proposed building is using LESS energy than would a building that met the prescriptive requirements.
One interesting new requirement is the need for skylights in most spaces, if the ceiling is 15 feet high. This sounds a little strange, but really makes sense. If a space can be lit with natural light, then there is much less need for artificial light. In addition, the orientation of vertical fenestration (windows) limits the quantity of east and west facing glass to each be equal to or less than ¼ of the total glass. Another new requirement is to provide a vestibule (air lock) or revolving door at all building entrances. This is to reduce infiltration of outside air, which is one of the major contributors to energy use.For HVAC systems, the minimum efficiencies for air conditioners and heat pumps are typically 15% to 20% higher. The minimum efficiency level depends on the type and size of the unit. The efficiencies for furnaces and boilers only increase marginally, as high-efficiency units are not (yet) required as the minimum. The bigger change in HVAC is with respect to the controls. DDC controls with graphics display and trending are now required on many systems, and there are many new control strategies that are necessary. Multiple boiler and chiller plants now require that all fluid flow is stopped through machines that are not operating.There are reductions to the Maximum Lighting Power Densities, with office buildings reduced from 1.0 to 0.82 W/Ft2 and schools from 1.2 to 0.87 W/Ft2. Exterior building lighting power is now restricted depending on the “Zone”, i.e. rural areas and state parks (Zone 1) are more restricted than a commercial business district (Zone 4). The number of exterior lighting applications is greatly expanded. Some of the power allowances are tradable, while some (i.e., building facades) cannot be exceeded by reducing the power for other applications.
Lighting control requirements change dramatically. In many space types, the lights cannot turn on automatically. There must be local control in the space. All lights must of course automatically turn off within 20 minutes of all occupants leaving the space. Automatic daylight responsive controls are required for sidelighting (windows) and for toplighting (skylights). Lighting controls must be tested to ensure they are properly calibrated and programmed.
Chapter 8 of ASHRAE 90.1 includes requirements for metering and controlling power to receptacles. However, the NJ adoption (in our infinite wisdom) makes this entire chapter “optional”. This will reduce the total energy savings expected from the standard. The minimum efficiency requirements for transformers are mandated by Federal Regulation (10 CFR 431), so what we previously used for high-efficiency (CSL-3) are now the minimum required. These changes are pretty comprehensive. The additional capital costs to implement these measures have been estimated and are justified by the energy cost savings. The new control measures have been made possible by advances in the technology and the reduction in their costs. We are seeing great success with new wireless controls that communicate via a mesh network, which further reduces the cost of implementation. It is an interesting and exciting time to be involved in this industry. I encourage everyone involved in building design and operation to learn the details of the new code requirements.
William Amann, P.E., DCEP, LEED Fellow is President of M&E Engineers, Inc. Board Member, USGBC-NJ.