Basic Firebrick sizes and shapes

Every business has a certain amount of terminology that is fairly specific to its field.  The refractory industry is no exception; following is a brief list of the more common terms we use along with a brief description or definition:

Fire Brick - This is a generic term that covers a huge variety of hard (dense) and soft (insulating) materials that are typically either pressed or extruded and then fired.  They come in various sizes and shapes as explained below:
Straights – The standard straight is 9” L x 4½” W x 2½” thick or 9”L x 4½”W x 3” thick.  Straights are available in larger sizes up to 18” in length, 9” in width and 4½” in thickness.

Square Edge Tile – This term refers to “big” straights which comprise 12” x 12” up to 24” x 12” with thickness ranging from 1½” to 3”.

Soaps – A term used to describe a half brick in width such as a 9” x 2¼” x 2½” or 9” x 2¼” x 3”.

Splits – A term used to describe the thickness of a brick thinner than 2½”, i.e. splits come in 1”, 1¼”, 1½”, and 2” thicknesses.

Arch - This shape tapers in thickness along the width over its entire length and is used to make sprung or circular barrel arched roofs either 4½” or 6” in thickness.  They are available in different tapers as follows:

      In 2½ thick brick a #1 Arch tapers from 2½” to 2 ⅛”
                                #2 Arch tapers from 2½“ to 1¾”
                                #3 Arch tapers from 2½” to 1”

      In 3” thick brick a  #1 Arch tapers from 3” to 2¾”
                                #2 Arch tapers from 3” to 2½”
                                #3 Arch tapers from 3” to 2”
                                #4 Arch tapers from 3” to 1”

Wedge - This shape tapers in thickness along the entire length of the brick and is used to make sprung or circular barrel arches 9”, 12” & 13” in thickness.  They are available in different tapers as follows:

      In 2½” thick brick a #1XW tapers from 2½” to 2¼” 
                                 #1W tapers from 2½” to 1⅞”
                                 #2W tapers from 2½” to 1½”
      In 3” thick brick a   #1W tapers from 3” to 2¾”
                                 #2W tapers from 3” to 2½”
                                 #3W tapers from 3” to 2”

NOTE: Larkin can easily calculate sprung or barrel arches if you will provide us with the span, desired rise and overall length of the arch.

Skew – A shape having a certain taper on one side or end to enable a sprung arch to be built.  Four major types are available in both side and end skews that relate to the rise of the arch, i.e. 1½”, 1.608”, 2” and 2.302” rise per foot of span.

Span - The horizontal distance between the inside of 2 parallel walls.

Catenary Arch – This type of arch begins on a horizontal plane and does not use a special skew.  In geometric terminology, it has the shape of a hyperbola. Unfortunately, there are no available tabulated combinations of arches or wedges to allow us to tell you how many of what tapered brick would be required to produce a catenary arch. Trial and error using different tapered bricks is the only way known to date.