Blockboards in India that carry the ISI mark, are manufactured as per the guidelines prescribed in the Indian Standards Document No. IS:1659 :2004 (Third Revision). Blockboard is made in two varieties, Interior MR grade and Exterior BWP/BWR grade, and each type has its own set of quality benchmarks defined.
Several types of tests are conducted on the samples of finished block boards to test their quality. Some examples of the types of checks carried out are listed below. For complete and accurate details readers are advised to refer to the actual IS quality document.
Dimensional stability (to check changes caused due to humidity).
Modulus of rupture and modulus of elasticity.
Resistance to water.
Adhesion of plies
Mycological tests (to check resistance to microorganisms)
Checking the boards for defects and finish
Recording the preservative treatments used for the core, cross bands and face veneers.
Moisture content of the core blocks before glueing (should not be greater than 12%)
Blockboard makers who manufacture blockboards as per the IS quality specifications can apply for and get the necessary certificate from BIS (Bureau of Indian Standards) after which they can use the ISI mark on their products.
Blockboards having genuine ISI marks, also have the IS specification number mentioned, as well as the CM/L number (Licence Number) that has been granted to the company.