Security Lighting: Urceri MT-912 Light Meter

Security lighting is an important part of a security program and it provides three main functions:

1. It can act as a deterrent for criminal or unwanted activity during night-time hours.
2. It provides a life-safety function for locations, e.g. lighting sidewalks, pathways, and parking locations.
3. Provides lighting for video surveillance subsystems.

When using security lighting the illumination of the desired object or area should be adequate enough to meet one or all the above mentioned functions. This means the light on the object or area needs be measured. We can do this by using a light meter, but first let’s talk about how light is measured. Light is measured in a few ways; first being its efficiency of light output per watt which is known as lumens. This measurement is based on the light output when new, but light output declines over time with use. Also the further the illuminated object or area is away from the light source the low the lumens on the object or area. The second way is to measure the intensity of light falling on the surface of an area or object known as luminance, and is measured in foot-candles (fc) or lux (lx). Foot-candles is the number of lumens per square foot, and lux is the number of lumens per square meter. One fc is equal to 10.76 lux or represented as a 1:10 ratio.

Using a light meter when performing security assessments is how you can check the lighting in an area or on an object. I recently started using the Urceri MT-912 Light Meter. This light meter is light weight, easy to use, and the 4-digital color LCD screen makes for easy to read outputs.

Some key features are:

• Measures luminosity from 0 to 200,000 lx, and it can measure in fc.
• Measures ambient temperature in both F or C
• High accuracy of ±3% rdg ± 8 dgts (10,000 Lux)

When checking lighting in an area or on an object you need to have a standard to follow. There are many standards that reference lighting and how it is to be uses in various settings. A good place to start is your state’s energy and lighting standards, but if your state does not have any standards there are other resources you can check out. The chart below illustrates various applications for light and recommended fc as per different standards.

Application	Minimum Lighting Level- IES Standards (foot-candles)	Other Recommendations
Perimeter Fence Open Parking Lot Covered Parking Structure Pedestrian Walkway Pedestrian Entrance Gatehouse Office General Use Retail Store	0.50 fc 0.20 fc – 0.90 fc 5.00 fc 0.20 fc 5.00 fc 30.00 fc 30.00 fc – 50.00 fc 50.00	NRC: 0.20 fc IES High Vehicle Traffic: 2.00 fc   IES: 7.50 fc @ ATMs DoAFM: 2.00 fc
IES: Illuminating Engineers Society of North America NRC: Nuclear Regulatory Commission DoAFM: Department of the Army Field Manual fc: foot-candles