Friday, January 10, 2014

One type of occupancy sensor doesn’t solve all your problems

The use of occupancy sensors is a very good energy efficiency solution for your building lighting automation. That being said some solution providers and building managers tend to use a simplistic approach to this solution. They try to automate all areas of their building with the same type of occupancy sensor. Not only this is a wrong approach, it is one of the main reasons that occupancy sensors get discredited. The main reason is that you can’t solve all your lighting automation solutions with one type of occupancy sensor.

Let’s stop and analyze this for a moment. For starts you have three main technologies in occupancy sensing. These are passive infrared, ultrasonic and dual technology (a sensor that combines both passive infrared and ultrasonic technology). This gives you a very good hint as to where a sensor applies and where it does not. Second, if you look at a catalog of any of the mayor manufacturer of lighting controls, when you get to the occupancy sensor section you will find more than three sensors. Not only that, you will find a range of occupancy sensors, all with different characteristics as of sensing area, technology and mounting or installation. They also give you examples as to where they recommend that you use this sensor, specifically the area. 

That is why you have to first survey each area with the manufacturers catalog. With the specs of the occupancy sensor try to select the appropriate one. The following are some recommendations for the selection of occupancy sensors in an area:

1.    Identify the area where you are going to use the occupancy sensor. This is the first step and will guide you well as to what occupancy sensor to use. Define if it is an open office, an area with cubicles or a closed office. Also hallways, bathrooms and closets demand other types of sensors. 

2.       Size the area. You need to know the size of the area, to select the best occupancy sensor that has the best coverage area. 

3.       Identify all the fixed objects in the area. This will determine line of sight. Remember that there are always objects that can be move in a specific area. These objects can block a wall switch eliminating the possibility of a wall switch sensor to be used. 

4.       Know where you are going to mount the sensor. If it is in the ceilings, take in to account what type of ceiling it is. This will determine which tools you will need to install the occupancy sensor.

5.       Find out what is the main activity that is going to be done in each area. You have to know if it’s computer work or an activity that involves people moving frequently. In areas where you are going to have little movement we recommend ultrasonic or dual technology. In high traffic areas it is better and more cost effective to use a passive infrared occupancy sensor. 

6.       If it is a new or an old building try to get the plans. If it is a new building, there is no way you can specify a sensor without an architectural plan view. Try to get one that has all of the furniture that they are going to use and where it is going to be placed. 

Again it is very uncomfortable for the occupants when the lights go off when they are working. This can not only discredit your occupancy sensing solution, it will also discredit you. Follow these and other recommendations and you will be off to a good start. Also if you need additional help always go to a trusted source. For any questions you can email them to: or use the comment section below.

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