As the name suggests, blast-rated doors can withstand the force emanating from highly compressed air spreading outwards after an explosion. The doors are usually constructed using thick steel and come with features designed to withstand high pound-force per square inch (psi) associated with blast events. Blast-rated doors are categorized based on the psi they can withstand.
Importance of Blast-Rated Doors
Blast-rated doors provide essential protection for staff and visitors in buildings at risk of terrorist attacks or factory facilities that manufacture or handle dangerous chemicals. In addition to saving lives, they also protect an organization from negligent death and injury lawsuits.
For a blast-rated door to be effective, the door and the building must be a Single Degree of Freedom system (SDOF). The degree of freedom refers to the number of parameters that define the state of a physical system. An example of an SDOF would be a blast-resistant building rated for 8 psi but has a window only rated for 5 psi. The lower psi for the window lowers the whole building's blast rating due to the single degree of freedom concept. A blast-rated door is only as strong as its weakest component, the Single Degree of Freedom.
Weight and Material
The materials used to construct blast-rated doors depend on the resistance level. Concrete, aluminum, and timber are common, but for high blast-resistance, steel is the best material for the following reasons:
Steel can withstand a high level of pressure waves.
Steel is fire-resistant. It has a low heat transfer rate and a high melting point.
It withstands expansion better than most materials. Steel bends and absorbs pressure, thus minimizing hazards and extending durability.
Steel has a much higher tensile strength when compared to aluminum, concrete, and timber.
A blast door's weight depends on its specifications, but the mean weight is about 450 pounds.
A lot of research and engineering goes into the design of blast-rated doors. It is, therefore, imperative that you use the door(s) in the way intended by the manufacturer. Below are pain points to avoid:
Keep the door closed: Blast-rated doors are over four times heavier than regular doors. This feature makes it tempting to leave them open or propped open for easier entry and exit. Unfortunately, doing this negates the benefits of having the door in the first place because it allows the blast force to enter the building instead of passing over it.
Regular maintenance: The sheet weight of a blast-rated door makes it susceptible to sagging. Loose hinges or latches can cause misalignment so that the door no longer fits in the frame. The hydraulic system that prevents the door from slamming and making it easier to open and shut should be checked regularly to ensure it is in perfect working order. You should schedule regular maintenance of blast-rated doors between every thirty to sixty days based on the advice from a qualified technician upon building install. The manufacturer's agent or a qualified technician should conduct the maintenance.