What is a Class A fire rating?
A “Class A” fire rating is given to materials with a flame spread index between 0 and 25 and a smoke development rating between 0 and 450. The flame spread index measures how fast a material burns. The smoke development rating indicates the concentration of smoke a material gives off as it burns.
| Flame Spread Index | Smoke Development Index | |
| Class A | 0-25 | 450 max |
| Class B | 26-75 | 450 max |
| Class C | 76-200 | 450 max |
Class A fire resistance standard is frequently required in commercial and residential structures. To receive this rating, one must undergo the American Society of Testing and Materials (ASTM) E-84 test. This assesses the surface burning characteristics of a material.
Read a complete overview of what the ASTM E-84 test entails.
What materials are Class A rated?
Temporary wall systems by TWS carry a Class A fire rating. Other materials known to achieve the rating are brick, fiber cement, and other types of stone and metal.
Which is better, a Class A or Class C fire rating?
A Class A rating is better. It’s the highest a material can get. Class C materials have a flame spread index of between 76 and 200. Plywood is a common example of Class C material.
How long can a Class A material burn?
Materials that receive a Class A rating can burn for approximately one hour. Some Class A-rated materials can burn for up to two hours, exhibiting some flame spread while still meeting other standards. Review a product’s certificate and testing data, if available.
What industries most commonly require materials with a Class A fire rating?
Class A materials are a common requirement in the construction, aviation, healthcare, manufacturing, education, and hospitality industries. TWS proudly provides modular containment solutions to all of these industries.
How does a Class A fire rating impact the safety of a building’s occupants?
Class A-rated materials can reduce or slow fire spread, increasing evacuation time. These materials also produce less smoke during testing, which indicates better air quality and visibility during a fire than lower-rated materials.
What are the benefits of using Class A fire-rated materials in construction projects?
Class A-rated materials can benefit code compliance, the cost of damage from fire, insurance policies, and your company’s reputation. That comes in addition to enhancing occupant and equipment safety on every job site.
TWS Class A-rated modular wall systems are also more sustainable, low-maintenance, and eco-friendly than other materials.
