Brian Ramsey
Part One
With high or rising crime rates in many Caribbean countries, most individuals turn to physical security measures as a means of protecting themselves against the possibility of being affected by crime at their homes. In most instances, those physical security measures usually involve fencing, gates, strengthened doors and burglar bars for doors and windows. Invariably all of these measures use iron or steel.
At the same time, we live in the Caribbean which means that our countries are surrounded by the Caribbean Sea and those beautiful turquoise waters that draw thousands of tourists to our shores every year, also exact a heavy price in terms of the impact on many of the common security measures.
�2 Dealing with sea spray
All buildings close to the sea experience fast rusting of metal and this is attributed to what is commonly called sea blast. This sea blast is actually the salt from the ocean being carried inland by the wind.
Many metals such as aluminium and iron naturally have a microscopic layer on their surface to protect from corrosion. For aluminium, this layer is called aluminium oxide, while for iron, the layer is iron oxide. In each case, this layer acts to prevent corrosion from occurring.
However, salt (sodium chloride), or actually the chloride part of salt, changes the ability of the oxide layer to protect the metal. Chloride always breaks down this layer causing pockmarks to form which is known as pitting, and once this occurs, then the rusting of the metal begins.
Another aspect of the sea blast is that in some locations the wind also carries fine particles of sand. This windblown sand has a double effect in that the sand constantly hitting on the metal causes pitting and the sand also has salt in it which begins to act on the pits, further breaking down the top layer of the metal.
Special attention, therefore, should be paid to the use of metal, especially iron and steel, in coastal environments. In addition, certain protective measures should be implemented. The effect of not taking the measures is that the metal surfaces corrode much faster and therefore the protective measures breakdown. Further, the building owner has higher maintenance costs because the various protective measures have to be replaced at a faster rate than at other locations.
�2 Screening with trees
One of the easiest measures for dealing with sea spray is to have a screen of trees on the perimeter of the property. As the wind blows in, the leaves strip the salt and sand from the wind lessening the amount of the sea blast that will actually reach to the building. In having this screen of trees, however, one should not violate the principles of Natural Surveillance for Crime Prevention through Environmental Design (CPTED).
The trees, therefore, should not block vision at the fence and should not provide an aid for people to surmount the fence.
Ideally, therefore, the trees should be planted outside the fence and as the trees grow, branches under eight feet should be cut off. The types of trees that are most beneficial for stripping the salt air are leafy varieties such as Almond and Sea Grape which have the added benefit of being able to live well in sandy, slightly salty soil.
Some fruit trees such as breadfruit and mango are also leafy varieties that are good for blocking the salt air. Fruit trees, however, have the disadvantages of attracting people to congregate in the area of the fence under the real or fictitious reason of coming for the fruits.
�2 Fencing at the seaside
Normal chain-link fences will rust at a fast rate in a coastal environment. Therefore, for those locations, it is recommended that a property owner use fencing that is coated with a polyvinyl chloride resin. The resin is hot extruded coated and is up to 22 mils (or .025 inch) thick.
This type of coated fence is smooth to the touch and will not rust, so it is ideal for installation in marine locations. In a Field Study of Fencing Materials conducted by the Naval Civil Engineering Lab at Port Hueneme, California, the evaluation indicates that "the vinyl-clad galvanised chain-link fence and accessories are performing better than other corrosion-resistant chain-link fences being investigated.
Although cost of the vinyl-clad fencing was slightly more (11 per cent) than the galvanised chain-link fence, the extra cost of the vinyl-clad fencing appears economically well justified because of its outstanding corrosion resistance, longer service life, and other benefits provided by the vinyl coating."
In the second part of this article, we will continue to look at chain-link fencing and also doors, windows and the type of paint to be used.
A wide range of professional development training courses on all areas of the security and public safety of businesses, properties, persons and communities are offered by the Caribbean Institute for Security and Public Safety at its scheduled classes and/or tailor-made in-house training to organizations. Please contact us at: 223-6999, info@caribbeansecurityinstitute.com or www.caribbeansecurityinstitute.com