Premises Security (part 9) Non-video surveillance

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In summary to-date
Part 1 discussed the different types of security systems.
Part 2 explained the differences between Local and Monitored alarms and Perimeter vs. State-change detection along with a look at some different video security surveillance cameras.
Part 3 looked at wireless vs. wired security systems.
Part 4 looked at setting up a video security installation
Part 5 covered remote monitoring of the video installation and security risks associated with that. It also considered using Motion Detection.
Part 6 Began an overview of NON-video surveillance devices.
It covered;
The “closed loop”, Micro/Magnetic-Reed/Thermatic & Pressure Mat switches
Part 7 Continued the overview of NON-video surveillance devices.
It covered detection of environment change rather than physical switch operation
It considered;
Pulsed Infra-red beams, Passive Infra-red (PIR) movement detectors, Proximity detection
Part 8 Completed the overview of NON-video surveillance devices.
We considered that security is more than just Intruder Detection so then looked at Temperature and Light/Darkness security sensors such as;
Thermal Fuses, Thermistor or semiconductor temperature monitors, LDR or Semiconductor light sensors.
And so to Part #9 of the series where we return to finish considering the two points raised in Part #1 of this series.

The first point was the trade-off of cost & size vs functionality, risk and aesthetics which led into the discussion of the various types of security system and the devices used (Parts #2 thru #8)
The second point was the possibility of having the "best of both" in a small easily installed surveillance system AND extended power coverage by use of a "UPS" for power assurance.

Let's now look at this second point.
The Trade-off

As I stated in Part #1, there is often a trade-off by the manufacturers of Digital Security systems, between size, cost and reliability. To keep size and cost down, battery capacity is minimised. Which is fine for 80-90% of the time.
We often have short-term power outtages of less than 2 hours and the supplied internal backup batteries work just fine.

Impact on Wireless Installations

In a wireless based security installation it is much less of a problem since the sensors all have their own battery power and are designed to operate 24x7 for many months on a new set of batteries.

Impact on Wired Installations

In a wired installation the sensors often source their power from the security control panel. If that is not the case then they derive their power directly from the mains supply.
In either of these scenarios, an extended loss of power supply can potentially render the system either totally inoperative or partially compromised.

Wireless or Central-Power Solution

If the system is wireless or all detectors source their power from the central panel, overcoming this weakness is relatively straightforward.
There are at-least two ways in which this can be addressed. Unfortunately both are quite bulky solutions sinc they both require the use of additional batteries.

1. Using Battery Extender Packs

If the system supports, or can be easily adapted to support, an external battery pack, then this is by far the cheapest, easiest and most efficient solution.
Essentially all that is required is some form of well-ventilated and secure housing for the desired quantity and capacity of batteries.

Technical Considerations

Technically you will need to consider the distance from the additional batteries to the security panel because of voltage loss over longer runs of wire. You will also need to stay within the manufacturer's specification for their battery charging circuitry.

Physical Considerations

The housing should be of sturdy construction capable of inhibiting fire and containing any possible battery explosion or leakage of battery acid.
Because batteries under charge give off explosive gases, the housing also needs to be well ventilated.

2. Using UPS Power Security

If your security system does NOT allow for attachment of additional battery capacity, an alternative may be to run the system off a UPS.

A UPS or Uninterruptible Power Supply generates utility-grade power (in many cases of superior quality) in the event of loss of supply to the premises.

UPS Ratings

UPS' come in all shapes and sizes and are rated in VA or Volt Amp units.
This measure is roughly equivalent to Watts which is the rating more commonly found on household appliances.

For the more technical readers, the VA rating takes into consideration Power Factor efficiency so the VA rating will always be higher than the Wattage rating (eg. a 1500VA UPS will deliver about 1200W)

Units start as small as 150VA but these are primarily designed to provide only a couple of minutes run-time on battery, sufficient only to automatically shutdown a small computer.

Calculating Your UPS Capacity

To calculate the UPS capacity required to support a system, an approximation can be made by taking the current draw of the system (either rated value or measured draw) then deciding how long you want the system to operate.

In the next installment, I'll work through an example calculation as we consider required run-time, battery life, and the different types of UPS.

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