CLASSIFICATIO\ OF BRICK Bricks used in structural work may he classified as follows: Common bricks are those used for brickwork, where appearance is not of special importance. "1'hey are burned at moderate temperatures. The best. well-burned common bricks are known as hard or cl rry bricks, or sometimes as Stock bricks. Those next the fire and heavily burned are known as clinker or arch bricks. Those from the underburned portion of the kiln are known as salmon, pale or soft bricks. The relative proportions of each kind in a kiln vary with the material and the skill used in burning.
Pressed. face or front bricks are those made with greater care, so as to secure uniformity of form and color. They are used for facing walls of common brick and where appearance is important, and are usually dry-pressed or repressed ],rick, Vitrified bricks are made from a more refractory clay and burned at a high heat to the point of vitrification. so that considerable softening and shrinkage occurs, though the brick still hold its shape. These brick; are commonly made in larger sizes than common bricks, called pacing blocks, and are used in street pavements. They are also frequently used in building construction, where obtainable at moderate prices. Blocks too lightly burned for use in pavements
often make good material for building construction.
Fire bricks are trade from clay which is lacking in fluxing ingredi ents. They are usually light in color, on account of the absence of iron oxide, and are u-ed when high temperatures are to be resisted.
Lnrlmckd brick; are made by coating the surface of pressed or re-pressed bricks before burning Nvith a slip, which will burn to the proper color, and covering with a glaze. The enamel is usually applied to a siuglc surface of a brick The following designations are also frequently employed: Sewer bricks are those common bricks which are so hard burned as to be practically non-absorbent of moisture, and are commonly used for lining sewers.
Compass bricks are shorter on one edge than the other, for use in circular walls.
bricks are made wedge shaped, for use in arches. Furring bricks are those having a surface grooved for plastering. Ornamental bricks are those having designs stamped in relief upon their faces, or bricks of special forms intended for use in making an ornamental surface design.