> FOCUS BY CRAIG DILOUIE
Today, a majority of energy codes are based on the following:
1. ASHRAE/IES Standard 90. 1, Energy Standard for Buildings Except Low-Rise Residential Buildings, published by
the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and the Illuminating
Engineering Society (IES). It is updated every three years.
2. The International Energy Conservation Code (IECC), published by the International Code Council. It is also updated
every three years. The IECC references 90. 1 as an alternative
standard, so designers have a choice.
To be clear, 90. 1 and the IECC are not codes. Instead, they
provide code-ready language that jurisdictions can use to
implement commercial building energy codes. Some states,
such as California, adopt unique codes.
For instance, in buildings that comply with a majority of
energy codes, lighting controls must turn off or reduce lighting
when not in use. These requirements have become more detailed
as codes evolved.
This article pores through 90. 1 and the IECC to summarize
New national reference standard
On Sept. 26, 2014, the U.S. Department of Energy (DOE)
named the ASHRAE/IES 90. 1 2013 energy standard as the
new national energy reference standard, superseding the
2010 version. This mandate requires all states to adopt an
energy code at least as stringent as 90. 1 2013 by October 2016
or justify noncompliance. Traditionally, 37 states have complied with these mandates, though that number dropped to
less than one-half of states for the earlier ruling recognizing
90. 1 2010.
The 2013 version of 90. 1 adjusted maximum allowable
lighting power allowances, with some up and some down. The
biggest changes to the standard imposed more detailed lighting
control requirements and a new tabular format for implementing lighting power allowances and controls by building
or space type. The tabular format was developed to simplify
application; the designer looks up a space type and sees at a
glance the requirements for that space. However, the control
requirements in the earlier text may appear confusing until one
realizes they are all directly connected to these tables.
For the space-by-space method, there are two tables: one
lists space types found in multiple building types, and the other
lists spaces generally found in one building type. The standard
contains language applicable to these tables that must be referenced separately.
For example, if using the space-by-space method in open
offices, a lighting power density (LPD) limit of 0.98 is prescribed. The room cavity ratio (RCR) threshold is 4, which
means an additional lighting power allowance of 20 percent
can be used if the actual RCR ( 2. 5 × room cavity height × room
perimeter length ÷ room area) is greater than the threshold.
Choices of controls are then listed.
In open offices, space controls are required for users, and all
lighting must be capable of reduction. If daylight is available,
daylight area lighting must be automatically, independently
controlled. The lights may be manual-on (ADD1) or partial-automatic-on (ADD1), and they must turn off automatically
based on either occupancy (ADD2) or a schedule (ADD2).
While energy codes cover new construction and major renovations, coverage is extending to lighting upgrades in existing
ASHRAE/IES 90. 1 and the IECC
C ommercial building energy codes impose design standards for nonresidential buildings’ energy efficiency. Many states have implemented an energy code to regulate building design. For lighting, the regulations combine prescriptive and mandatory requirements. Primary prescriptive
requirements include maximum lighting power allowances by building or space type. Primary mandatory requirements cover a wide range of lighting controls. There may also be administrative and testing requirements, such as
functionally testing lighting controls and turning over documentation to the owner.
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