Factors, such as ignition temperature, smoke toxicity and flame-spread potential, are crucial when considering the fire safety rating of building materials. The U.S. is dominated by red cedar, and this type of lumbar has a Class B rating, which has higher levels of chemical retention in comparison to Class C ratings. Many construction projects require materials from places like Rocky Mountain Forest Products with a minimum Class B rating. If you are considering the option of using red cedar, familiarizing yourself with the concept behind flame-spread rating, understanding how it is measured, and being able to compare the rating of the red cedar with other alternatives can help you make a more informed decision.
What Is a Flame-Spread Rating?
The flame-spread rating describes the rate of which the flame is able to spread across a certain surface area. It is one of the most tested properties of construction materials, will influence the safety of residences within a building, and is separated into 3 distinct categories: Class A (0 - 25), Class B (26 - 75) and Class C (76 - 200). A lower flame-spread rating will indicate that the fire will spread in a slower manner across the surface. On the contrary, a higher flame-spread rating will indicate that the fire will spread quickly. Naturally, a lower rating will indicate that the construction material has a higher fire resistance and will be able to better control the rate of which the fire is spreading.
Since red cedar falls in Class B, it has a relatively low flame-spread rating. This means that red cedar lumber is suitable for a wide variety of different purposes, as it is mostly resistant to fire.
How Is the Flame-Spread Rating Measured?
The flame-spread rating is typically measured through the tunnel testing. The tunnel testing is designed to measure the rate and distance of which the fire is able to spread across a certain test surface. Generally speaking, the tunnel test is conducted by having a strip of material installed and exposed to gas flames at one end. The rate of which the fire spreads, along with the distance that it travels to, is then measured to produce a fire-spread rating.
Depending on the data that has been collected above, the frame-spread rating is generally expressed as a number on the continuous scale, which is then divided into three different classes
What Is The Flame-Spread Rating of Red Cedar, and How Does It Compare With Other Alternatives?
Western red cedar has a flame-spread rating of approximately 69 even when it has not been treated. This is relatively low and helps to ensure that red cedar is an appropriate construction material choice for numerous jobs. In comparison, Douglas fir has a flame-spread rating of approximately 90, and maple has a flame-spread rating of approximately 104.
By comparing the flame-spread rating of different woods, homeowners will have a better appreciation of the value of the wood, as well as the amount of security and longevity that the wood can offer in the long run. Keep in mind that U.S. codes have specified that the maximum flame-spread rating for interior wall and ceiling finishes is roughly at 20.
Depending on the likelihood of a fire happening in your area, you may wish to invest in red cedar lumber as your primary choice as a construction material. Red cedar does not only possess a low flame-spread rating, but it can also offer durability, rot resistance, decay resistance, among many other favorable qualities. Red cedar lumber is extremely versatile in nature and can be incorporated into many different projects making it a common choice for many businesses. Its low flame-spread rating, in particular, has helped it give a name for itself.