Saturday, November 30, 2013

Sally Port Security - Medieval To Modern

Dealing as we do every day in the business of security, we are used to hearing the wide range of words that it encompasses. There are, however, occasions when we come across a term that is familiar yet unusual at the same time. Today we're going to take a look at such a term; one that many of you will have heard and perhaps used, particularly if you are involved in prison and correctional facility security, yet don't fully appreciate its relevancy and origins. That term is sally port.

First of all we need to travel back in time, about 700 years in fact to medieval Europe when it was commonplace for castles to be attacked. Often the attack took the form of a siege where those inside the castle would have to endure bombardment and attack over a period of days, sometimes weeks. The attacking force would be camped outside the castle's perimeter walls making all manner of attempts to breach them from using siege engines like the trebuchet or siege towers. Those inside the castle had few options of defence so castle construction evolved to offer more options for a successful defence. These included the introduction of the portcullis and the sally port.

Metal portcullis in medieval castle perimeter wall
The portcullis is something most people are familiar with - a massive metal or wooden gate mounted on vertical grooves within the perimeter wall, usually at the main entrance to the castle. The portcullis could be raised or lowered via a winch attached to rope or chain. Sometimes two portcullis would be constructed so that, if attacked, one portcullis would be raised inviting attackers to enter then once they were at the second, closed portcullis, the first would be lowered, trapping them in between.

A sally port, on the other hand, is little known by most people. In medieval times, it was an opening or door within a castle perimeter wall which could allow defending troops to quickly exit the castle and mount a surprise attack on those laying siege outside. The troops would then return just as quickly through the sally port. Needless to say, the sally port was always carefully guarded. Some medieval castles even built underground sally ports for the same purpose - surprise attacks on besieging troops on the outside perimeter - and great examples of these can still be seen today such as at the sally ports at Knaresborough Castle in England.

If you look at the two words in the term it becomes self-evident what a sally port is:
'sally' is of  Latin origin (salire) meaning to jump (ie. surprise attack)
'port' is of Latin origin (porta) meaning a door

Prison buildings often have sally ports
Today, the word sally port is still used with essentially the same meaning - ie. a guarded doorway or opening for the control of movement of personnel/people. Many sites actually use 2 doors within the sally port area (just as the old double portcullis worked 700 years ago).

Modern, high security sites using sally ports include nuclear weapons and munitions storage areas, currency production facilities and correctional facilities.

Those guarding the sally port usually do so remotely, monitoring and controlling the space between the two doors. Strict, pre-set numbers of people will be allowed through one door whilst the second door remains closed. Then in the 'secured' space they will be checked whilst the first door is then locked. Once given clearance the second door will be opened allowing them through. When through, that second door will be closed whilst the secured area is double-checked before the procedure can be re-commenced.

Why, as suppliers of perimeter security systems, should we talk about sally ports? Well, one of the increasingly popular uses of our security technology is to protect prison perimeters including their sally ports. A good example is this retrofit prison electric fence supply that we were involved in for a US Dept Of Corrections prison which has two sally ports.

So next time you hear a term with a slightly unusual ring to it, spend a little time investigating .... you never know you might be in for an interesting history lesson!

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Wednesday, November 13, 2013

Sensor Technology – From Nature To Microwave Security

The word sensor is possibly one of the most important in the entire vocabulary of the security industry. Putting it simply, to keep something safe you need to be able to detect movement in that area and sensors play a vital role in monitoring and detecting movement. However, before we go into the detail of our particular type of sensor technology as used in a holistic perimeter security system, let us take a look at where the idea of using sensors actually comes from - nature.

As this Wikipedia section on sensors in nature explains, every living organism on the planet has sensors - biological sensors. It seems nature has created a range of specialized cells that help living things sense the world (and its dangers) around them. These cells have a myriad of capabilities ranging from the ability to sense vibration and magnetic fields to moisture and temperature. There are special cells that can even detect toxins and nutrients in the environment. Within our own human biology, we have cells that can sense levels of oxygen and glucose. So when you read about the latest sensor technology, no matter how clever it might seem, bear in mind that it's probably a replication of a system that nature developed first.

Returning then to our world of sensors, the most recent development in our product range has been that of microwave sensors which we produced to assist with intrusion detection.

Essentially, microwave beams are generated to create a zone of protection and should a difference within that zone be detected then analysis (certain pre-set criteria are checked) followed by the triggering of an alarm result. The system comes with a wide range of adjustment features and, very importantly, is not affected by bad weather. A good example of our Flexiguard™ Microwave Barriers working effectively in this context is on the perimeter of a storage facility of a famous whisky company in Scotland - where there can readily be fog, heavy rain or snow! If you missed it, click here to read our post telling the story of how this installation came about.

If that hooks your interest you can learn more about the technical side of these microwave detection sensors, the features offered, frequency spec, power supply requirements, etc. Download here.

Distilleries and breweries also use other products in our range such as our electric fencing and fence detection technology. Click here to read about perimeter security for this particular industry.

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