We recently took a look at Type I construction and the characteristics associated with it. Basically, Type I construction is also referenced as fire resistive construction. The question always becomes, what is fire resistive?
We have to remember that a Type I building has structural components that are non-combustible and then is rated, usually at two hours or higher. In addition, the components are commonly protected. This protection comes from fire resistive products applied to the structural components.
So, what is Type II construction. The easiest way to define a Type II building is that is has the same structural characteristics as a Type I in that it is non-combustible construction. The major difference is that it is not protected.
For example, in a Type I building we will see columns and beams covered with fire resistive spray on material as seen in the first picture. In a Type II building these columns and beams are not protected and will be exposed during a fire.
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A Type II building can be sprinklered but is still considered Type II based on the rating of the structural components. A rule of thumb is typically a Type II building will have rating requirements of one hour or less. A Type I building will require a rating of components of two hours or more. Again, this is a rule of thumb and not always the case in all examples and codes.
Just remember, that the structural components will be attacked quickly in Type II buildings because they are not protected with any fire resistive materials.
I know this is pretty basic stuff but I find it to be a good reminder of what we are looking at when we get around to these buildings. Chiefs and company officers must know the differences and be able to expect the building to react certain ways based on the type of construction. We all know that the building type and materials can affect how we attack the fire and deploy our people.
Stay safe and be careful.
Thoughts and prayers with the CFD and all families and friends affected.