To determine the Dimension Tolerance Test of a Burnt Clay Brick.

To Determine the Dimension Tolerance Test of a Burnt Clay Brick.

INTRODUCTION:

Bricks used in the construction of buildings are always of variable dimensions. This variation may be negligible in the individual brick but proves to be significant when large numbers of bricks are laid in position. The dimension tolerance test is conducted to find out the accuracy of the dimensions in the bricks. This test proves to be significant in determining the quality of a brick.

MATERIALS REQUIRED:

• Bricks

APPARATUS REQUIRED:

• Meter Scale

THEORY:

Dimension Tolerance: It is defined as the amount or percentage of permissible limits of variations in the physical dimension of a material. Dimension may vary within certain practical limits without significantly affecting the functioning of equipment or processes. A variation beyond the tolerance is said to be non-compliant, rejected, or exceeding the tolerance. The dimensional test is carried out to determine the precision or accuracy of the dimensions of the bricks. The bricks should be of a fairly uniform size. Slight variation is unavoidable. Therefore, any variation from the prescribed dimensions of the bricks should be within the specified limits.
The test involves the measurement of the three dimensions of bricks (length, width, and height) separately for several bricks laid in a line along the respective dimension. In all twenty (20) bricks are taken at random from the main sample already collected. The surfaces are cleaned by removing small projections, blisters, and clay particles. All the twenty bricks are now placed in a line, in contact with each other, on a smooth surface. Their position depends upon the dimension which is going to be counted for. The total length is then precisely noted. The bricks are placed along the length when the length is to be determined along their width, when the total width is determined and along the height when the total height is to be determined.
For high class (A Class) bricks the size variation or tolerance should be very little. The standard twenty bricks of 19cm x 9cm x 9cm size when tested should fulfill the Following Requirements:

Procedure.

1. First, take a single brick and measure its length, breadth, and height with the help of measuring tape or scale.
2. Take twenty bricks randomly from the stacks as per the sampling rule. 3. Place the bricks on a smooth surface as shown in the figure for the respective dimensions of the bricks.
3. Measure the length, width, and height by the meter scale.

Figure 1. Bricks laid in length.

Figure.2.Bricks laid in width.

Pre-Cautions:

Observations:

Review Questions

1. Why random bricks are selected for sampling?
2. What are the Dimensions for First Class Bricks?
3. State the importance of this test.