Good Quality Brick Specifications Based on ASTM, IS, and CSA
Madeh Izat Hamakareem
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Bricks are widely used in building construction because of their adequate strength, durability, availability and low cost. They can be made in desired shape and size. Bricks which are used for construction purposes shall poses good qualities otherwise the safety and serviceability of masonry structure would be compromised.
Hence, this article presents qualities of good bricks based on the IS 1077, IS 2180, ASTM C62, ASTM C216, and CSA A288 in the cases where it is different from ASTM.
Good quality brick specifications based on American Concrete Society for Testing and materials (ASTM), Indian Standard (IS), and Canadian Standard Associations (CSA) include:
compressive strength of bricks
shape of bricks
brick construction materials
1. compressive strength of bricks
According to ASTM C62, compressive strength of good quality brick shall be not smaller than those provided in Table 1. CSA A288 provides the same result for compressive strength but only for severe and moderate exposure conditions.
The crushing strength of the brick to be used in all types of works shall not be less than 7.356MPa unless otherwise specified when tested according to IS:3495 (Part-1).
Table 1 minimum compressive strength of bricks
Grade of bricks
Minimum Compressive Strength gross area, MPa
Average of 5 Brick
Fig.1: compressive strength test on brick
2. Shape of bricks
Brick are shaped during manufacture by molding, pressing, or extrusion using hand or machine. Ordinary bricks are rectangular solids. But sometimes bricks are given different shapes to make them suitable for particular type of construction.
They shall have regular and uniform size, sharp straight and right-angled edges.They shall have smooth rectangular faces with parallel sides and sharp corners.
Fig. 2: Shape of bricks
3. Brick construction materials
Bricks shall be constructed from suitable soil and kiln burnt. They shall be well burnt throughout but not over-burnt.
Similarly, ASTM standard specify that, brick shall be of clay, shale, fire clay, or mixtures thereof, and burned properly to meet good quality brick requirements.
If the bricks are burnt excessively or under burnt, they lose equality of color on the surface and strength.
4. Brick size
Good quality bricks shall have uniform size. The size of the conventional bricks shall be 225 x 110 x 75 mm. Only bricks of one standard size shall be used in one work unless specially permitted by the Client / Consultant. The following tolerances are permitted in the standard conventional size adopted on the particular work.
Length plus or minus 3.0 mm
Breadth plus or minus 1.5 mm
Depth plus or minus 1.5 mm
The size of the modular bricks shall be 190 x 90 x 90 mm or 190 x 40 mm.
As per ASTM C62, the size of Solid brick shall be as specified by the purchaser. The maximum permissible variation in dimensions of individual units shall not exceed those given in Table 2. Table 3 provides different sizes for hollow bricks.
Table 2 variations of dimensions of solid bricks
Specified dimension, mm
Maximum Permissible Variations from Specified Dimension, plus or minus, mm (CSA A288)
Up to 76, inclusive
Over 76 to 102, inclusive
Over 102 to 152, inclusive
Over 152 to 203, inclusive
Over 203 to 305, inclusive
Over 305 to 406, inclusive
Table 3Hollow Brick Minimum Thickness of Face Shells and Webs
Nominal Width of Units, mm
Face Shell Thicknesses, mm
End Shells or End Webs
Cored or Double Shell
76 and 101
Fig. 3: brick sizes
5. Brick color
Good quality brick needs to have uniform color. According to IS, good quality brick has deep cherry red and copper color.
Fig. 4: brick color
6. Brick appearance
According to Indian standard, bricks shall show a fine-grained, uniform, homogeneous and dense texture on fracture and shall be free from lumps of lime, lamination, cracks, air holes, soluble salts causing efflorescence or any other defect which may impair their strength, durability, appearance and usefulness for the purpose intended. They shall not have any part under-burnt.
Fig. 5: brick appearance
7. Water absorption
After immersion in cold water for 24 hours, absorption by weight shall not exceed 15 percent of the dry weight of the brick when tested according to IS:3495 (Part-2).
According to ASTM C62, maximum saturation shall conform to the values provided in Table 4. This requirement can be neglected If the brick are intended for use exposed to weather where the weathering index is less than 50 but compressive strength shall not be less than 17.2MPa
Table 4 Maximum water absorption of bricks
Grade of bricks
Maximum Water Absorption by 5-h Boiling, %
Average of 5 Brick (CSA A288)
Individual brick (CSA A288)
No limit (---)
No limit (---)
Fig. 6: water absorption
8. Brick cracks
Good quality bricks shall be free from cracks, flaws and nodules of free lime as per Indian standard. With regard to ASTM C62, brick unit shall not develop a crack that exceeds, in length, the unit’s least dimension
9. Brick soundness
They shall give a clear metallic ringing sound when struck by a mallet and shall not break when dropped on the ground on their flat face in a saturated condition from a height of 600 mm.
Efflorescence in bricks shall be within limits prescribed in (Not more than 10% of the exposed area of the brick shall be covered with a thin deposit of salts) IS:3495 (Part-3).
According to ASTM standard, bricks are not required to be tested for efflorescence unless requested by specifier.