Fire doors are designed to delay the spread of fires, smoke and heat. Smoke and heat are often as deadly as the flames themselves, and their travel must be limited if people are to escape fire disasters unharmed. Fire doors also need to be easy to operate when a fire occurs, otherwise they’ll impede people’s escape attempts. As a result of these goals, the glazing material used in fire doors has to meet approved regulations.
The glazing, or glass panels that allow you to see through the fire door, must meet standards established by NFPA 80. Section 1-7.1 of this important code dictates that only glazing materials that are labeled as fire resistant and meet proper standards may be used.
The standards this rule mentions are specific impact safety ratings for glass strength. These ratings designate that glass must not break when subjected to the impact of a certain weight when it is swung from a certain height. For this reason, many types of approved glazing are reinforced, either by chemical or manufactured means. Various types of approved glazing include materials such as:
• Ceramic glass
• Borosilicate glass
• Wire mesh reinforced glass, which stands a better chance of withstanding fire
• Double-pane glass filled with sodium silicate, also known as water glass, which swells with heat exposure to block heat transfer
Each type of glazing is rated for certain temperature and impact strength. The glazing best for your fire doors should not only withstand generic fires like electrical and waste paper fires, but also potential high temperature blazes caused by the combustion of any industrial materials you might have on site.
It’s important to ensure that every component of your fire doors meets applicable safety regulations. Although fire doors are supposed to stop the spread of hazards, the fact that they are rarely built as monolithic units means that they usually have weak points, and glazing is a common one. Make sure that all windows in your fire doors meet standards by consulting with a fire protection company before you install them.