Sensors that detect the presence of people are called occupancy sensors. There are several technologies that detect occupancy, but infrared, microwave, ultrasonic, and video image processing are the most commonly used. These sensors will usually connect to the building's IoT(Internet of things) network and send data to building management systems and room booking systems that can automate lighting, HVAC, and ventilation control, and provide information to occupancy analytics systems to monitor desk usage, meeting room efficiency and occupancy. It is the combination of privacy and security protection, limited external impact, and the ability to deploy them in a variety of open concept interior spaces that makes these occupancy sensors so efficient.
Are occupancy sensors required by code?
It is a matter of course that occupancy sensors are required by the energy code, which is updated after every 3 years by IECC. So following IECC revisions in 2021, more buildings now need occupancy sensors. The new update has added break areas, workspaces, and open office spaces to the list.
The IECC version 2021 reduced lighting power allowances, control requirements, and outlined certain lighting-related issues. For new construction and renovations of buildings, many countries use the International Energy Conservation Code (IECC), which outlines energy-efficient design.
Furthermore, occupancy sensors do not seem to be necessary for open areas in warehouses, since time switches seem to be necessary. The final change is that turning off the lights in the space now requires manual control.
Take a look at a few more updates:
Power allowances for interior lighting: Interior lighting power allowances have been reduced in the IECC 2021. (It's all in watts/square foot.) As per the building space, light power indoors is decreased from 0.79 to 0.64, from 1.06 to 0.84 in retail, from 0.81 to 0.72 in schools and universities, and from 0.48 to 0.45 in warehouses. Consistent decline in allowances marks the maturation of LED.
Controls for lighting: The IECC contains a number of mandatory standards for lighting control. Accordingly, the lights must be automatically turned off or reduced, for that supplemental manual switches need to be provided. With the IECC, there are two ways to achieve compliance: the simplified path is built on luminaire-level controls, while the discrete path is based on discrete controls.
Sensors for occupancy detection: There are many places where occupancy sensors can be useful, such as in large open spaces and in closed spaces. The IECC 2021 adds corridors as a list of areas that must be monitored for occupancy and with lighting power reduced by at least 50% within 20 minutes if the corridor is empty. Open office lighting should be auto-on in the control zone, and lighting in other spaces can be turned on to 22% of full power or left off at all.
Light-reducing controls: A manual switch that adjusts the light must be installed in locations without occupancy sensors and daylight-responsive controls without requiring a 50% reduction in light. In IECC 2021, dimming options are clarified to include shutting down all luminaires or all luminaire rows to 30%–70% and continuously dimming from full light to less than 20% power.
Daylight-responsive lighting controls: IECC requires the control of general lighting in daylight-brightened side and top zones. According to IECC 2021, the secondary daylight zone is to be controlled next to the primary zone near vertical fenestration. A side light is now standard on all rooftop monitors. As part of IECC 2021, all applications need to include automatic dimmer settings so that daylight is automatically dimmed to at least 15%. Furthermore, daylight-responsive controls may reduce power further in open offices, warehouses and corridors that use occupancy sensing but not more than the occupancy-sensor level.
Parking garage lighting: IECC 2021 includes an entirely new section that requires occupancy sensors or time switches to control parking garage lighting. Furthermore, the power use needs to be reduced with an occupancy sensor along with a maximum control zone of 3,600 square feet. During sunset and sunrise, entrance and exit lighting should be reduced by at least 50%.
Control of plug loads: Control of plug loads is now possible through lighting controls, which is a big change. A minimum of half of all permanently installed 15/20A 125V receptacles must be controlled in certain applications. It is possible to install controlled receptacles in split-controlled receptacles, with the top part of the receptacle controlled, or set them apart from uncontrolled receptacles. Depending on the system, an occupancy sensor or timer switch may be used to control the receptacles.
Exterior lighting: In the evenings and in the daytime, exterior lighting must automatically be turned off. IECC 2021 suggests reducing the light level to 50% of the full level after hours for dusk-to-dawn lighting. When not in use, certain outdoor luminaires in parking lots must be dimmed by occupancy sensors. It is necessary to turn off exterior lighting when there is sufficient sunlight. Lighting on building facades and in the landscape must be turned off at night when they are no longer needed. If you have exterior lighting, either you should reduce it at a certain time or reduce it by occupancy during the night.
Additional energy savings:
Building new construction requires 10 credits out of 15 options, one of which is to achieve lighting-power reductions beyond what is outlined in the codes. Rather than requiring individual control of overhead lighting, digital controls provide users with the ability to operate their own lighting.
The occupancy sensors are playing an increasingly important role in controlling the building HVAC system. By regulating and providing demand control ventilation, these sensors not only help occupants feel more comfortable but also lead to a more sustainable environment. In commercial buildings, occupancy sensors can reduce energy usage tremendously when analyzing occupancy patterns and daily use. Commercial buildings must meet energy-efficiency codes to maintain their efficiency. Governments and states enact them and ask that they be followed.