NFPA Conference & Expo

4  FM quick reads on security

1. Keep Security Equipment Cool To Extend Service Life


Managers can purchase video cameras, motion detectors, and other standalone security devices in enclosures that are rated IP65/66 or NEMA 4/4X, and they require nothing more than a sunshield. But in some cases, managers need to install equipment intended for interior use in exterior locations to support the security system. This equipment might include fiber optic converters, network switches, and power over Ethernet injectors.

Video cameras can feature a sunshield that stands off from the camera housing 1 inch or so and acts to absorb and dissipate heat before it reaches the housing.

Cooling systems can be classified as open or closed loop and active or passive systems. Open-loop systems use outside air to cool the components. They are often passive, using convection and heat dissipation. Closed-loop systems use internal air to cool the components. They are often active, using an external device or system to cool internal air.

Overheated components too often are a factor in the premature failure of security equipment. In some cases, the mean time between failure decreases exponentially as the heat increases beyond the operating range of the equipment.

It is also important for managers to ensure that equipment enclosures provide effective thermal management for the longevity of security equipment. The enclosure must be able to dissipate heat or prevent heat buildup beyond the equipment's maximum operating temperature. In very cold climates, managers might need to provide additional heat to keep the equipment from operating below the equipment's minimum operating temperature.

But since electronic equipment tends to reject heat inside an enclosure, overheating tends to be the greater problem. Too often, equipment is installed in an exterior enclosure with no thought to the heat load the equipment will generate inside the enclosure. The size or surface area of the enclosure plays a role in the amount of heat it can dissipate without using vents, fans, heat exchangers, or air conditioning.

The enclosure's location also might be a factor. If the enclosure is located in direct sunlight, it will have a significant increase in internal air temperature, and calculations to determine heat buildup become increasingly complex. The enclosure's color also takes on greater significance. For example, white enclosures will reflect much of the radiant heat from the sun.


2.  Use Equipment Properly To Ensure Security Success

As external threats to institutional and commercial facilities seem to grow daily, access control and security remain high on the priority lists of maintenance and engineering managers. In addition to specifying the most appropriate doors and door hardware to protect occupants and facilities, managers also need to understand the installation considerations related to security technology, such as video cameras and motion sensors, to avoid equipment failure.

One of the quickest ways to experience failure of any mechanical or electrical device is to install a device intended for interior use outside. Many security devices, including video cameras and motion detectors, are designed and made for interior use only. They will not withstand the extremes in temperature and humidity that weather can bring.

When selecting any of these devices, managers should look for an International Electrotechnical Commission (IEC) 60529 or a National Electrical Manufacturers Association (NEMA) 250 rating.

The NEMA 250 rating system also addresses enclosures resistance to the penetration of solid and liquid materials. But it also addresses such requirements as corrosion resistance, gasket aging, and construction practices that the ingress protection (IP) codes do not address. So while it is possible to select NEMA ratings that satisfy or exceed the IP code criteria, it is not possible to select IP codes that meet or exceed any given NEMA rating. Still, managers can use some rules of thumb to better select equipment suitable for indoor or outdoor use. Generally, equipment that is rated IP20 or NEMA 1 is intended for installation in a climate-controlled environment. Equipment that is suitable for exterior installation should have one of the following NEMA or IEC ratings: IP54 or NEMA 3 or 3R; IP65 or IP66 or NEMA 4 or 4X; IP67 or NEMA 6; or IP68 or NEMA 6P.

When specifying equipment for exterior applications in corrosive environments, managers must go beyond the IEC 60529 ratings. Saltwater or marine environments are corrosive environments for some equipment. Security devices installed within 12 miles of a coastline probably should be rated for a corrosive environment or enclosed in a housing designed to protect equipment from a corrosive environments.

Managers can purchase video cameras, motion detectors, and other standalone security devices in enclosures that are rated IP65/66 or NEMA 4/4X, and they require nothing more than a sunshield. But in some cases, managers need to install equipment intended for interior use in exterior locations to support the security system. This equipment might include fiber optic converters, network switches, and power over Ethernet injectors.


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