In the flame-spread rating test, a score of 0 to 25 constitutes a Class 1 rating. The score is relative and balanced between asbestos cement sheet, with a score of 0, and pure red oak, with a score of 100. Building materials with a Class 1 fire rating are often man-made or nonorganic substances.
A fire-resistance rating typically means the duration for which a passive fire protection system can withstand a standard fire resistance test.This can be quantified simply as a measure of time, or it may entail a host of other criteria, involving other evidence of functionality or fitness for purpose.
As the name states, this rating pertains to how well a particular wallcovering performs in the event of smoke or fire. While a wallcovering will certainly burn, if it has a rating of Class A, that means that it reduces how quickly the fire spreads.
The Class 1 Fire Rating definition is the flame spread index and smoke development index, which means how fast a flame will spread when introduced to the material and how much smoke it produces. Building inspectors and code require the numbers stated above to reach that Class 1 Fire Rating – 450 or less for smoke development and less than 25 ...
This test does not replicate actual geometry and scale of fires in most industrial/commercial occupancies. FM Approved Class 1 interior wall and ceiling panels meet these minimum jurisdictional requirements, and go significantly further to test and certify the fire performance of these products.
What is Class 0 ? Class 0 is a Building Regulations rating and not a British Standard Classification. To attain Class 0, a sample must meet Class 1 for spread of flame and also meet the fire propagation requirements of BS476 Part 6. (Hence we quote Class 1/0 as our product meets both criteria).
The most stringent rating available for building materials is Class A. Class A materials have an FSR of 0 to 25. The classification system provided by the NFPA allows architects and engineers to select the best materials for fire safety when starting new projects.
For example, 1-hour fire-resistant construction will withstand the standard fire exposure for one hour before the structural integrity of the wall fails. Most home construction is currently non-rated. This is not to say that non-rated homes have no fire resistance, it’s just less than one hour.
Figure 1. This aluminum roof covering has a Class A fire rating “by assembly”. In this case, the roof assembly consists of the aluminum roof covering, overlapping layers of a capsheet roofing material (for the improved fire rating), and structural sheathing, all attached to the lumber framing.
Class F means that the product is not documented, the product does not meet the criteria for any class, or the manufacturer has not provided the fire properties for the product. Class F cannot be combined with any additional class either. When establishing the Euroclass for pipe insulation, the sub-index “L” is used (e.g., A2L – s1, d0).