Every building is different by virtue of its location, construction and by its contents, therefore the crime risk created varies accordingly. The best time to address the security of a building is during its design, when your local Police Architectural Liaison Officer can give free, impartial and site-specific advice.

Many modern business buildings are built speculatively for rent; the developers do not therefore know what the end use is going to be. It is vital, when assessing the viability of a building as to its suitability for business, that the in-built security measures are correct to protect that business.

The Building Shell
This includes all roofs, walls, doors and windows and any other area where intruders can gain access.

Flat roofs with roof lights, cellars with party walls to adjoining cellar space or access hatches, and even sewer tunnels can be exploited by criminals if the perceived gain is high enough.

Although doors and windows are the usual entry points for burglars, insulation and metal foil construction or even single skin brick walls used in some modern commercial buildings can easily be cut through with saws or disc cutters. When carrying out a risk assessment the structure should be examined closely.

Doors
Some general points for all external doors:

• Doors should be flush with the building line, avoiding recesses.

• The door should fit the frame well enough to prevent forcing open with jemmies or crowbars.

• Frames should be as strong and as securely fixed as the door itself.

• Wooden doors should be at least 44mm thick.

• Care should be taken with the strength and durability of other materials such as aluminium and Upvc.

• External hinges should be protected and hinge pins made non-removable.

• All glazing in doors should be of laminated glass or fitted with security film to prevent accidents and to deny entry (see Windows page 12).

• External doors and security doors should be fitted with a closer. These should always be on the inside face of the door.

Fire Doors and Emergency Exits
The fire escape door outside which the smokers gather, or which is propped open in hot weather, is a common area where business security is compromised.

• External doors should be covered by the building alarm and have a 'door open' warning, even when the alarm is not set.

• Fire doors require particular attention. Security must not impede escape.

• The fire officer must be consulted before any alteration to external doors. Failure to do so may result in contravention of the fire certificate.

Letterboxes
Letterboxes are another potential weakness. Letter cages should be used. If the risk assessment indicates any possibility of arson or mail-borne threats such as letter bombs, fire suppressing and blast-containing letterboxes must be considered.

Windows
These are often the most vulnerable part of any building especially those on the ground floor and particularly at the rear of the building.

• It is advisable to reduce the amount of opening panes to the minimum.

• All ground floor windows should have substantial window locks.

• For health & safety reasons all low-level glazing (windows and doors) requires safety glass. These should be glazed with laminated glass or have a suitable security film applied to the inner face.

• Appropriate window films are available to address risks of terrorism, vandalism and accidental breakage and the risk of injury from flying glass fragments.

• Window bars can be fixed to deny unwanted access but should only be considered where emergency exit in the case of fire would not be affected.

• The use of blinds or reflective film to enhance privacy and prevent easy view of high value equipment or stock inside ground floor rooms should be considered.

• Particularly vulnerable windows can be fitted with grilles or shutters.

Grilles, Shutters & Bars
Sliding grilles and shutters can be used to effectively protect windows, doors and emergency exits in most commercial premises.

Grilles can be folded to the side of the door or window when the building is occupied. They can be made of expanded metal, galvanised steel or welded mesh and can be coated in a variety of colours to give aesthetically pleasing security without interference to natural light or ventilation.

Shutters can be fitted either externally or internally and can be manually or electronically operated.

Your local fire officer should be consulted in cases of emergency exit protection.

Locks and Keys
The simplest form involves a mechanical lock that uses a key to control one door. The principle of suites of locks, allowing senior staff to access a range of doors throughout the building with a single key, but limiting others to their zones of responsibility only, is a more sophisticated use of key locking.

This does have disadvantages in that stringent key management is vital and any lost keys place the security of the whole building at risk.

Nominated staff members need to be appointed as key holders to attend out of hours in the event of fire, crime or other emergency. Many alarm and security companies provide a key holding service. In addition, some will organise urgent repairs, boarding up etc. on your behalf. This will usually be done in conjunction with your alarm company, to comply with Police alarm response policy.

Care should be taken to ensure that key holders are not compromised or called to the building under a false pretence only to be threatened and forced to allow access to the building and switch off alarms.

Electronic access control is now common. Door entry phones - many with visual verification by small video cameras and swipe cards or tags which are 'read' by computer operated detectors are all readily available.