Manufacturers are ready to meet this demand with simple, two-pole, wall-switch sensors or more capable digital lighting management systems that can support more complex requirements (Figure 2).
Vacancy detection systems are now required for room lighting in newly constructed hotels. A control device will be mandatory near the entrance door in new construction projects to control all permanently installed luminaires and switched receptacles. A common approach to error-proofing this process is to employ a device requiring the room keycard be inserted in a slot to activate the lighting circuits. Additionally, a vacancy sensor will be required to automatically turn off lighting in the bathroom within 60 minutes of the occupant leaving the space.
Often an area identified for energy savings, stairway lighting control is one new requirement using the new sequence of operations of lighting controls. All enclosed stairwells must
reduce lighting power by at least 50 per cent within 30 minutes of all occupants leaving the space.
Controls will also benefit lighting designers. As previously mentioned, when additional control methods are employed on top of mandatory requirements, an interior lighting power allowance may be generated to offset lighting loads in other locations. For example, occupancy sensors controlling open-office cubicle lighting fixtures employing continuous dimming operation for personal light level control could provide a 30 per cent interior lighting power allowance bonus. The allowances are calculated as lighting power under control multiplied by the applicable space control factor.
Taking advantage of daylight is mandatory for both ‘primary sidelighted areas’ (i.e. windows) and ‘toplighted areas’ (e.g. skylights and clerestories). When an enclosed space meets the minimum floor area requirement (23 m2 for sidelighted areas and 84 m2 [900 sf] for toplighted areas), lighting automation with three control steps is required:
- off to 35 percent;
- 50 per cent to 70 per cent; and
- fully on.
The ranges allow for daylighting requirements to be accommodated by bi-level switching systems, but this is another example of a good application for continuous dimming systems to provide unobtrusive daylighting control. Allowances are also made for sunlight blocked by adjacent buildings or other structures that can significantly reduce the daylighting opportunity.
To ensure the lighting control system is understood and implemented according to requirements, the goals and conditions must be documented as part of the submittals. Once installed, lighting controls must also be functionally calibrated, programmed, and tested, according to manufacturer’s instructions and new minimum test procedures now provided in the code. Written certification must be provided to verify conformance.
Minimum test procedures include such common items as verifying occupancy sensor placement, sensitivity, and time-outs, as well as confirming low-voltage switches and time schedules are programmed to turn off lighting. Daylight harvesting systems must demonstrate they will reduce lighting power based on available natural light. The tests must not be performed by the individuals involved in the design or construction of the systems, and this responsible party must be stated in the construction documents. Finally, due to the increased complexity, reliance on technology, and proper setup to achieve higher levels of energy efficiency, the code also ensures the owner is provided with all necessary information to understand, use, and maintain the systems.
Expanded scope: receptacle loads
Automatic receptacle control is a completely new requirement added to ASHRAE 90.1, Chapter 8, “Power.” Plug loads have increased to the point of becoming the largest category of electrical energy use, perhaps in part by assuming some task lighting loads as lighting power densities have been squeezed (Figure 3). While not exclusively intended for control of task-lighting plug loads, receptacles can be conveniently tied into lighting time-of-day schedules or by occupancy detection systems to meet the requirement. At least 50 per cent
of all 125-V 15- and 20-amp receptacles in computer classrooms, along with private and open offices (including modular partitions), must now be controlled.
The next generation of standards is expected to continue to push energy efficiency and sustainability by continued expansion of existing control requirements (e.g. adding more light level steps or requiring continuous dimming in certain spaces). Control zone size will be constricted, ultimately to individual fixture control capability. Automated receptacle control will be required in more spaces.
Adding new technologies and techniques provides tools to generate further savings (e.g. control of emergency circuited lighting together with general lighting, while providing a reliable and safe response to emergency situations). Automated reduction of lighting loads at times of peak electrical demand will begin to be a requirement, rather than a feature implemented by certain demand-response programs.
Lighting quality requirements will be considered in parallel with further lighting power density reductions with a goal of also improving overall indoor environmental quality. One example already available is personal lighting control that allows each occupant to select the appropriate light level for their task at hand (Figure 4). Finally, energy monitoring will provide the means to sustain energy efficiency by supplying the tools required to determine how and where energy is being wasted.
The amendment to adopt ASHRAE 90.1-2010 maintains Ontario’s status as a Canadian leader in using its provincial code to regulate energy efficiency in new buildings. Control of lighting energy use plays a vital role toward helping meet the increasing need for energy conservation. To date, no other Canadian jurisdiction has set a building code energy efficiency requirement for large buildings that meets or exceeds MNECB by more than 25 per cent. This amendment to OBC will provide flexibility for designers and builders in meeting the code’s energy efficiency requirements without compromising important objectives related to energy efficiency.
Andrew Parker, P.Eng., LC, LEED AP, is a controls and lighting specialist at Salex/Marnik Inc. With more than 20 years of experience in lighting, electronics, and controls, he is a member of Illuminating Engineering Society of North America (IESNA) and is the communications chair for the Toronto Section. Parker can be reached via e-mail at email@example.com.