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