DIMENSION TEST OF CLAY BRICKS

Dimension Tests ( IS: 1077) :

Table 1 : Scale of sampling and Permissible number of Defectives for Visual and Dimensional Characteristics

While preparing the estimates standard sizes of the bricks are considered and the number of bricks to be used in the structure are estimated. If the dimensions of the brick will have deviations more than the permitted, the estimated cost will inflate. Further, more number of brick-bats or plaster/mortar will be required to make up the standard dimensions specified on drawing for construction. This may disturb the regular specified type of pattern (bond) and may impair the strength and consequently cracks may develop. 20 pieces out of selected pieces (Table 1) are taken and are laid flat as shown in Fig. 1. The cumulative dimensions of the bricks should be as discussed in Sec. 2.5. The tolerances (Section 2.5) on the sizes of bricks are fixed by giving maximum and minimum dimensions, not on individual bricks but on batches of 20 bricks chosen at random. It follows from this method of measurement that batches are likely to contain, bricks outside the prescribed limit of tolerance. Such lots should be rejected to avoid complaints about the variation of perpends.

Fig.1 Measurement of Tolerance Common
 Building Bricks

Fig. 2 Arrangement of Bricks