Escape 1800 Insert Installation and Operation Manual
36
If the extension of the masonry hearth is raised at least 4" (102mm) from the floor
protection, a non-combustible material without an R factor is sufficient.
If non-combustible material floor protection needs to be added in front of and level with the
hearth extension of the masonry fireplace, an R factor equal to or greater than 2.00 is
required.
The use of an R value is convenient when more than one material is going to be used in
the hearth extension to cover the combustible surface. This is because R values are
additive, whereas K values are not.
