Lighting

A guide to energy code compliance in lighting systems

Architecture, engineering and construction professionals must apply emerging technologies to satisfy the rigorous demands of energy codes while meeting their clients’ operational goals and budgetary constraints

By Tim Milam and Ross Bush November 11, 2021
Courtesy: Jordan & Skala Engineers

 

Learning Objectives

  • Demonstrate the progression in building codes toward energy efficiency and identify the entities that establish standards for energy consumption in built environments.
  • Describe the pathways to achieving code-compliant lighting power densities with collaborative, qualified professionals.
  • Understand code requirements for lighting controls as critical components of lighting design, as well as how those requirements can differ by issuing entity.

Since building energy codes were first released, the approach to efficiency has evolved to include lighting system control and design. As the design team determines which code is best for its project, it’s important to understand how the codes developed to their current state, the nuances between each code and how different standards can impact lighting design.

The first official energy code began to take shape in the early 2000s. Code requirements were initially regarded as routine for project completion. Additionally, there were few significant updates for several years.

The building codes’ progression toward energy efficiency accelerated in 2009, when different lighting power densities were established for different types of spaces and general on/off controls were mandated. Lighting technology had developed to provide more advanced control strategies and more light output with less energy input. In turn, the codes and standards progressed rapidly, transforming many professionals’ design approach.

Lighting power densities have decreased as technology has advanced from incandescent lamps to LED technology. Daylight controls, as well as occupancy and vacancy controls, have become mandatory requirements in codes and standards; even considerations for skylights in certain types of spaces may be required to maximize natural daylight.

Today, ASHRAE and the International Energy Conservation Code set the standards for energy consumption in newly constructed buildings.

ASHRAE is a well-known entity that establishes globally accepted energy consumption standards. Around the world, ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings is used as a benchmark for setting minimum energy performance standards and energy codes, as well as minimum requirements for energy-efficient design. Compliance is performance-based, meaning that a building’s energy consumption report must be data-driven, with calculations and analyses to support the results of efficiency efforts. Reporting energy data to code officials is voluntary in areas of the United States without an existing building energy code. However, owners, developers and investors could reduce a typical building’s energy consumption by as much as 50% with ASHRAE’s practices.

This standard provides minimum energy-efficiency requirements for designing and constructing new buildings and new additions to existing buildings, including new lighting system design and equipment. It also outlines how design teams and project partners can ensure compliance with various requirements. ASHRAE 90.1 is updated continually to address more efficient technologies and emergent research as quickly as possible. While this standard provides the framework for many codes in the U.S., ASHRAE’s members are from over 132 different countries and their focus is on efficiency standards that can be applied around the world.

The IECC establishes baseline energy-efficiency standards for newly constructed projects. It addresses the design of walls, floors, ceilings, lighting, windows, duct leakage and more, in relation to energy efficiency. The IECC is sometimes referred to as the United States’ “model energy code” because there is no federal energy-efficiency code.

As a U.S.-based organization, its aim is to provide guidance for states adopting building energy codes. Every three years, officials across the nation vote on changes to IECC standards to ensure that new projects incorporate the latest best practices, systems and technologies to meet the most up-to-date thresholds for safety and efficiency.

Comparing the standards

ASHRAE Standard 90.1 and the IECC address many aspects of building energy consumption, including energy efficiency in plumbing, building envelopes, insulation, roofs, heating, ventilation and air conditioning and more. Both standards represent pathways to achieving code-compliant lighting design and controls; however, one standard might not be appropriate for certain buildings.

The ASHRAE standard does not address low-rise residential buildings, like single-family homes, making the IECC the primary resource for such projects in the U.S. Additionally, while one engineer or design professional may have extensive experience with ASHRAE, another professional may adhere to the IECC.

Many owners and developers who build and sell assets quickly aim to keep first costs low; contrastingly, long-term asset holders may be more interested in energy savings over time. The “right” standard is the one that meets the objectives; the choice of which standard to use for a project should be based on the efficiency goals and the standard that will best achieve them, as neither is inherently better than the other.

Collaboration among project partners, owners, developers and investors is key when deciding which standard is most appropriate for a project. Building types and mechanical systems are often drivers when determining which standard will be more first-cost effective or which will better support long-term energy savings. For example, high-rise residential buildings in certain climates need specific mechanical systems; however, ASHRAE doesn’t provide guidance for many of the equipment and systems that directly affect building occupants, including information technology equipment and elevators.

Architects, electrical engineers and other project partners should compare compliance avenues not only among each other, but with owners and developers. Understanding whether first costs or operating costs are most important, selecting the best compliance route and ensuring adherence to both priorities takes a team of experts.

The coordination, communication and extensive, detailed knowledge required to meet each need and objective warrants combined expertise across multiple disciplines. The same standard must be adhered to by project partners, including architects, during the planning and design phases, as well. If an architect begins a project using IECC standards, for instance, it’s imperative that the engineer continues using the IECC. Otherwise, the building would be at risk of a code violation for combining ASHRAE Standard 90.1 and the IECC. Licensed professional engineers and sustainability experts can collaborate to help ensure that selected energy-efficient systems and equipment achieve code compliance and energy savings according to the priorities.

Lighting design and controls

Achieving code-compliant lighting power densities can be challenging without proper guidance. But collaborative, qualified professionals who understand the latest codes and the most effective technology can help meet project goals and code requirements.

In lighting design, “efficacy” is defined as the lumens per watt of a lighting fixture or luminaire, itself; the density is the number of watts per square foot allowed in a room based on the type of occupancy. Density requirements in building and electrical codes provide lighting control guidelines for different types of spaces, buildings, etc. They can involve controls for automatic shut-off, daylight responsiveness, bilevel switching (where alternate rows of light features or fixtures are independently controlled) and more.

The birth of LED technology was a significant step forward for lighting density standards. When it was first introduced, electrical codes decreased the allowable watts per square foot because LED made it possible to achieve better lighting with lower wattage. The density has been further reduced as LED technology has developed and become more common, as well as effective. Engineers and design professionals would be unable to meet current power density objectives using previous technologies, such as fluorescent, high-intensity discharge and incandescent lights, due to their high wattage.

Although residential units are exempt from lighting power density requirements, the IECC mandates that luminaires in these dwellings must meet a specific efficacy requirement; however, fluorescent and LED lighting easily help meet this requirement. The code drove innovation in the architecture, engineering and construction industry by providing incentives to manufacture and implement LED lighting, which has resulted in progress for density standards and, in turn, energy efficiency.

 

Lighting controls

Code requirements for lighting controls are critical components of lighting design. Once lights are designed to meet a certain wattage standard, lighting controls can be established to help ensure the optimal efficiency of lighting sensors, systems and more with automatic, timed-based settings.

Electrical codes have never had occupancy requirements to automatically turn lights on upon sensing activity, for example, but they do call for manual controls to turn lights on, as well as automatic controls to turn them off. It’s unnecessary to have lights turn on automatically in response to activity, as windows often provide more than enough natural light to see indoors during the day.

However, there was previously a requirement for either an occupancy sensor or two switches near the entrance to a room: one to turn lights on at 50% brightness and the other to turn lights on at full brightness.

NFPA 70: National Electrical Code is the most widely adopted electrical code in the U.S., as well as several other countries. This set of regulations acts as the standard for electrical safety in residential and commercial buildings, including the latest requirements for electrical wiring safety, overcurrent protection and watts per square feet.

While they share some basic similarities, the NEC, ASHRAE and the IECC are inherently different. All are updated every three years and make modern guidelines widely available. Any of the three can also be implemented by any jurisdiction internationally. Contrastingly, ASHRAE and the IECC address building energy consumption, while the NEC is specific to safety standards for electrical systems and equipment. NEC takes precedence over both IECC and ASHRAE, as governing bodies can codify their standards, including energy standards to be enforced by the NEC.

Different methods can be used to incorporate effective lighting controls design.

  • Wireless: The newest method, wireless systems involve a power pack installed on the line voltage circuit to provide power to luminaires. All controls are wireless, communicating with the power pack via a gateway that turns luminaires on/off and adjusts the fixtures’ light levels. Wireless controls do not require an electrician to install wiring to each control device; however, they do contain batteries that eventually need to be replaced. These systems are easily modified, as the controls can be moved anywhere. Additional controls can easily be added with no wires involved, providing future scalability for the owner or developer.
  • Low-voltage: Low-voltage lighting controls operate similarly to wireless controls, but with low-voltage cabling between the control device(s) and the power pack. Once installed, relocating or adding devices can be difficult because of the wiring connections; however, these controls allow for customization of lighting control zones. Low-voltage wiring can also be installed by someone other than a licensed electrician, which can help reduce labor costs.
  • Line voltage: Line-voltage lighting control is the longest-standing method and provides the basics required for lighting control. These systems connect to the line voltage of the lighting circuit and are not easily modified or adjusted once installed. All wiring for these systems must be installed by a licensed electrician.

However, guidelines for lighting control efficiency differ between ASHRAE and the IECC. For instance, the ASHRAE requirement for daylight responsiveness stipulates that lights within a certain number of feet from windows (typically 15 feet) must have sensors that automatically dim or brighten the artificial light according to how sunny it is outside. Versions of the IECC also require daylight responsive controls in spaces with more than 150 watts, based on the distance from the top fenestration height to the floor.

Regardless of which standard is selected, project partners across multiple disciplines (architecture, electrical engineering, etc.) must communicate to select and design around, the same standard. While adhering to one standard might save costs in some areas, it could have a different effect on another aspect of the project.

For example, if a project using ASHRAE includes a parking garage, it may trigger an immediate expense but lower long-term energy costs because recent versions of ASHRAE require automatic lighting controls in residential parking structures. Experienced electrical engineers, lighting designers and registered professional engineers collaborate with their clients to prioritize the standards and systems that meet owner and developer’s goals for first costs, as well as operating expenses.

In addition to varying guidelines, lighting design can prove challenging because every product is different and the technology is proprietary. Occupancy sensors, for example, differ significantly by manufacturer. Including each sensor in computer-aided design or Autodesk Revit renderings can also make the design appear cluttered.

Experienced electrical engineers and design professionals can mitigate these issues by taking a matrix approach and by collaborating to ensure that appropriate products and systems are applied throughout planning and design. Rather than draw every component, a matrix approach relies primarily on equipment schedules that are based on the types of rooms or buildings, as well as the types of lighting devices. Once the schedules are drawn, the contractor can learn how to control the different types of rooms’ lighting according to each type of device. ASHRAE and IECC standards can be just as nuanced as building code requirements, but skilled project partners can help navigate energy-efficient technologies to ensure compliance.

A guide to lighting design standards featuring a comparative look between ASHRAE 90.1-2013 and IECC 2015. Courtesy: Jordan & Skala Engineers

A guide to lighting design standards featuring a comparative look between ASHRAE 90.1-2013 and IECC 2015. Courtesy: Jordan & Skala Engineers

Green building programs

Today’s energy code standards are on par with those set by green building programs. Building code updates have even standardized many sustainability initiatives that are not necessarily related to a specific energy program. As a result, green building programs are not as costly as they used to be, although there are nuances in each program’s lighting standards.

Achieving both green building certification and energy code compliance may add another layer of complexity to a project. While some requirements overlap, different green programs can have different requirements, some of which might even seem more stringent than energy codes.

For example, the National Green Building Standard has 13 practices for multifamily lighting design and controls that address topics from induction cooktops to smart appliances; however, there are no similar practices provided by U.S. Green Building Council’s LEED. While LEED does not require a certain percentage of light fixtures in residential spaces to be high efficiency, the NGBS does.

Experienced third-party sustainability consultants also help meet building envelope requirements. Recent versions of the IECC and ASHRAE order commissioning and/or testing of lighting and lighting controls. During a project’s construction and final inspection, function testing is required to ensure that lighting and daylight controls were installed and operate as originally intended.

Energy-efficiency codes can also have prescriptive and performance specifications. The IECC and ASHRAE both include prescriptive specifications, which are energy-efficiency requirements that must be met. Performance specifications are based on energy modeling results and help determine whether a building in operation is meeting its efficiency objectives. How and when these specifications must be met are strategic decisions, best made by project partners who understand the owner or developer’s goals. When each partner intentionally communicates with the others, they help ensure that they’ll be the best stewards of the project’s budget and their client’s success.

The evolution of building energy codes provides multifamily owners, developers, and investors and with options to help maximize building efficiency and lower utility expenses. Each standard can differ significantly, however, in terms of their requirements and how they influence savings.


Tim Milam and Ross Bush
Author Bio: Tim Milam is a Principal with Jordan & Skala Engineers. He led the firm’s electrical discipline for more than two decades. Ross Bush is a Principal at Jordan & Skala Engineers. He brings more than 20 years of electrical design and leadership experience; he is the current leader of the firm’s electrical discipline.