How many samples should I take from a lot of 200 urinals?

For a lot size of 151 to 280, you should take a sample of 20 units as per Table 1.

If I inspect a sample of 20 units and find 2 defective ones, what should I do?

You should reject the entire lot, as the permissible number of defectives for a sample size of 20 is 1 (Table 1).

Does this standard apply to faucets and fittings?

No, this standard is specifically for vitreous and fire clay sanitary appliances like WCs, basins, and urinals. Fittings have their own sampling plans.

What is the smallest lot size covered by this standard?

The smallest lot size for which a sampling plan is specified is 'Up to 25' units, which requires a sample size of 3 (Table 1).

IS 9140

: 1996

Method for a sampling of vitreous and fire clay sanitary appliances

CurrentSpecializedTesting MethodMEP · Sanitary Appliances and Water Fittings

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This standard specifies the method of sampling and the criteria for conformity for vitreous china and fire clay sanitary appliances. It provides a statistical basis for accepting or rejecting a lot based on the inspection of a representative sample, primarily for quality control purposes during manufacturing or procurement.

Method for a sampling of vitreous and fire clay sanitary appliances

Quick Reference Values

Sample size for lot size 51-908 units

Permissible defectives for sample size 80 units

Sample size for lot size 151-28020 units

Permissible defectives for sample size 201 unit

Sample size for lot size 501-120050 units

Permissible defectives for sample size 503 units

Practical Notes

This code is used for bulk inspection (lot acceptance) at the factory or project site, not for evaluating single items.

The definition of a 'defective' item is not in this code; it must be sourced from the relevant product specification standard (e.g., IS 2556).

The sampling plan is a single sampling plan for normal inspection, based on statistical principles.