A security grille is unlike a shutter in that it provides the opening with protection while also remaining transparent to airflow and light. This is ideal for properties that will benefit from an opening for airflow and light, but also needs to maintain visibility for operation or appearance during the day.
Fixed Grilles
Fixed grilles are permanently installed with bolts or welds on the masonry adjacent to the window frame. The purpose of these grilles is that in order to remove them, one has to use power tools due to the fact that there are no hinges or locks to access. These grilles are of a steel or wrought iron bar design that is fixed to multiple points of a frame.
These types of grilles are ideal for situations that require a permanent protective grille without the need to remove a grille for access or maintenance. These types of grilles fit well with basement windows, ground floor windows that are of a commercial nature, and a vulnerable opening of an industrial or business nature. The ease of installation of these grilles is attractive as the fixings go through solid masonry or metal frames and stay that way.
While these types of grilles do provide protection, there are also some limitations. For instance, cleaning a window that is behind a grille becomes more difficult due to the obstruction provided by the bars. Maintaining the frame and painting it also becomes partially obstructed due to the grille’s position. These are issues that are associated with installing these types of grilles. Knowing what these issues are will assist during the placement of the grilles.
Fixed grilles used as emergency window exit routes must comply with fire safety and building regulations. Building regulations specify that all window exit route grilles must be easily removable from the inside. The quick release mechanism achieves this without tools and is compliant with the fire safety and building regulations.
Retractable Grilles
Retractable grilles are ideal for applications where an unobstructed area is vital. These grilles are foldable and can be retracted into a channel on one side of the opening. During use, the grille is extended to the other side of the opening and locked for security. For versatility, the grilles feature a concertina mechanism. For a wide opening, the grille is retracted.
Among several applications, retail outlets are one of the primary users of retractable grilles. These grilles are often retracted for use during business hours, while an extended grille is used for closing the retail outlet. A grille that is extended blocks the opening and provides security. This is especially important for outlets that are susceptible to theft.
The mechanism of a retractable grille requires frequent maintenance compared to fixed grilles, which is an added cost. Contaminants and debris buildup in the tracks and the system stiffens if not maintained. Twice daily opening and closing for a busy outlet requires a yearly maintenance to keep it running smoothly.
Electronic operation is better for large openings and multiple openings that share the same space. At the press of a button, a motor will extend or retract the opening grille. A battery backup allows the grille to remain operational during an outage. Manual opening is the best option for smaller openings or single doorways.
Internal vs External Mounting
External grills are installed on the outer frame of the window. They are designed to protect the glass itself from window strikes and vandalism, meaning an intruder would have to remove the grill first to strike the glass. For this reason, most commercial buildings opt to install external grills.
Internal grills are placed behind the window on the property. They can prevent entry into the window, but offer no protection from breaking the glass. Because they are less visible, they are a more aesthetically pleasing option, but come at the cost of breaking glass more frequently.
Materials
Steel is the most popular choice for security grilles. It is a cost effective, strong, flexible, and durable material. It resists rust when galvanized or powder coated. Security bars come in a variety of shapes and profiles with round, square, and flat bars available.
For historical or listed buildings, Wrought Iron is a good option. It can be shaped and formed in patterns to ensure the grilles appear less functional which is often ideal. It requires more maintenance than steel, but for the right building, is a much more pleasing option.
Aluminium window grilles are lightweight and non-rusting and are a good option in applications where there is less of a risk and a lower need for strength, in comparison to mild steel.
Domestic Applications
Most window grille applications are installed on ground floor windows, garage side door windows, and basement windows. These locations of the window offer easy access to any residential or commercial property that is not sufficiently controlled or protected by standard window locking systems. A ground floor, rear window grille removes an easy access point to the property without the need to install an additional security system or burglar alarm or upgrade the glazing.
Prior to any purchase, what are the external security permissions granted, especially on residential properties? No external security systems are permitted, and many local authorities do not grant approval for external security systems to be installed. An experienced installer will be informed of the planning policies in a particular area.
Fixed grilles are ideal security systems for second homes and properties that are unoccupied for lengthy periods of time.
Commercial Applications
Window grilles are a common, flexible security system application for use on shop fronts, service entrances, back office window systems, and dividing external partitions. The type of grille is determined by the function. A floor level back office window grille will be a fixed grille, while a grille on a shop front will have to be retractable and fold away for daily trading.
Internal security grilles isolate segments of a building. Different access points in a stock room in a store, a cash office in a warehouse, or a server room in an office; all can be concealed behind internal security grilles.
The extent of the security grilles installed in commercial buildings is often dictated by insurance concerns. Some insurance policies require certain specifications on type, bar spacing, or security rating. It is important to review the insurance policy prior to placing the grille order to ensure satisfaction of the insurance company’s requirements.
Industrial Applications
Grilles are common on industrial sites to secure windows on loading bays, vulnerable perimeters and internal high security areas. The specifications are designed to be more substantial than on regular commercial grilles; these may include thicker bars, deeper fixings, and wider frames fixed into openings in structural members of the building.
Mesh partitioning is a common means of securing a large open area in an industrial building. These partitioned enclosures, such as a secured stock area in a warehouse, an IT equipment secured area in a factory, or a secured area in a distribution center, can be large, yet removable. The system lends itself well to changes in the layout of an industrial building.
Fencing usually creates a perimeter, but not absolute building security. Anti-climb grilles or mesh add additional security beyond standard height fencing. These systems are most typically used on industrial sites where the building and perimeter security are of equal concern.
Bar Spacing and Specification
Bar spacing is designed to meet security standards. A gap of 100 to 125 mm provides adequate security for most applications. Reduced spacing provides even greater security but allows even less light through. The resistance to cutting and bending is increased during the manufacturing process if thicker bars are used. The specification of grilles for insurance purposes may be compromised if the bars are not of adequate thickness. The same may be true for specification when meeting a required security standard.