The ISI mark on plywood is not just a sticker — it guarantees your product has been tested to Indian standards for strength, moisture resistance, and formaldehyde emission. Here's what it means.
What is ISI Certification?
ISI stands for Indian Standards Institute — now the Bureau of Indian Standards (BIS). The ISI mark (IS:303 for plywood) certifies that a product has been independently tested and conforms to the specified Indian Standard.
What ISI Certification Tests
- Glue Bond Strength: Tensile shear strength of the adhesive joint
- Moisture Resistance: Cyclic boiling water test for BWP; cold water soak for MR
- Formaldehyde Emission: E1 level (≤1.5 mg/L) mandatory for indoor use
- Bending Strength: Modulus of rupture and modulus of elasticity
- Face and Core Quality: Void percentage, delamination, core gap limits
How to Verify an ISI Mark
Every ISI-certified panel must have: the ISI mark logo, the IS number (e.g., IS:303), the manufacturer's licence number, and the batch/date of manufacture. You can verify any licence number on the BIS website at bis.gov.in.
Warning: The market is flooded with uncertified plywood carrying fake ISI stamps. Always buy from authorised dealers and ask for the mill's BIS licence number.