How many bricks should I take from a truckload of 10,000 bricks for testing?

For visual and dimensional checks, take 20 bricks. For physical tests (like strength and water absorption), take 10 bricks. (Tables 1 & 2)

What is considered a 'lot' of bricks?

A 'lot' is a collection or consignment of bricks of the same class, size, and from the same source, manufactured under similar conditions. The tables cover lot sizes up to 50,000 bricks. (Clause 3.1)

What happens if a sample fails the visual and dimensional tests?

If the number of defective bricks in the sample is greater than the permissible number (e.g., more than 1 for a sample of 20), the entire lot is deemed not to conform to the requirements and is liable for rejection. (Table 1)

How many samples are needed for compressive strength test?

From the overall sample drawn for physical tests (e.g., 10 bricks), a subset of 5 bricks is to be used for the compressive strength test. (Clause 5.2.1 and IS 3495 Part 1)

IS 5454

: 1978

Methods of sampling of clay building bricks

CurrentFrequently UsedTesting MethodMaterials Science · Clay and Stabilized Soil Products

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This standard specifies the statistical sampling procedure for burnt clay building bricks to assess conformity to requirements. It covers the scale of sampling for visual, dimensional, and physical tests, and provides criteria for acceptance or rejection of a lot.

Methods of sampling of clay building bricks

Quick Reference Values

Sample size for visual check (Lot of 2001-10000)20 bricks

Permissible defectives for visual check (Sample of 20)1 brick

Sample size for physical tests (Lot of 10001-35000)15 bricks

Number of bricks for compressive strength test from sample5 bricks

Number of bricks for water absorption test from sample5 bricks

Maximum lot size mentioned in tables50000 bricks

Practical Notes

Ensure that the lot from which samples are drawn consists of bricks from a single source and batch to ensure homogeneity. Do not mix bricks from different suppliers or trucks into one lot.

The selection of bricks must be truly random. Avoid the common mistake of picking easily accessible bricks from the top or sides of a stack. Follow the procedure in Clause 4.3.

This standard only covers sampling. The actual tests on the sampled bricks must be conducted as per IS 3495 (Methods of Tests of Burnt Clay Building Bricks).