Windows are the weakest part of most commercial buildings and often the first line of defence against security threats. Window security film uses a pressure sensitive adhesive that will hold your windows together if they are broken, giving you, your staff and your assets protection against airborne shards of glass. If you're planning on installing window security film, this guide will help you choose the appropriate thickness, length and attachment method.

Thickness and Length

Security film is manufactured using polyester and ranges between 4 mils and 14 mils in thickness. Most films come packaged in rolls of 36, 48, 60 or 72 inches, and vary between 50 and 100 feet in length. Thicker films have a greater a break, tear and puncture threshold than thinner films.

Four mils should be sufficient for buildings in low-risk areas; eight mils or above is suitable for average-risk areas; and 14 mils or above is recommended for high-risk areas, government buildings, and establishments that harbour goods of significant financial value, such as banks. You can increase the thickness of your security film by adding new layers if you'd like to enhance security after the initial installation.

Daylight Attachment

The "daylight" method is the most commonly used method of film installation. The film is applied to the glass with an adhesive, leaving a slight gap between the edges of the film and the window frame. This method is considered sufficient for low to average-risk properties. The daylight method doesn't always provide adequate protection against explosions and gunshots; therefore, a stronger binding should be used for high-risk properties.

Anchored Attachments

There are two types of anchored attachment: "mechanical" and "wet." Both offer a greater degree of protection than the daylight method and are suitable for high-risk properties.

The "mechanical" method requires a physical attachment. The film is applied to the glass with an adhesive and anchored to the window frame using metal baton strips. Depending on the desired level of strength, it can be attached on either one, two or all four sides of the window frame.

The "wet" method requires two types of sealant. The film itself is applied using the daylight method but with a smaller gap between the film and the edge of the window frame. A stronger adhesive is then applied to the outer edges of the film to create a tighter bond. The only downside is that the stronger adhesive is visible.

An ounce of prevention is worth a pound of cure. While security cameras and motion detectors can be effective deterrents, they cannot defend your property against physical threats from vandals, burglars and terrorists. The simple addition of window film can play a major role in your security plan by making your property more resilient and difficult to penetrate.