IS 303 vs IS 710 — what the standards actually mean

The one-line summary

• IS:303 governs BWR — boiling water resistant plywood.
• IS:710 governs BWP — boiling waterproof plywood.

A board sold as "waterproof" without an IS:710 stamp is a marketing claim, not a specification.

What the standards actually test

Both standards test glue-line performance under sustained water immersion. The difference is duration and severity:

• IS:303 (BWR) — the glue line must survive 8 hours of boiling water without failing.
• IS:710 (BWP) — the glue line must survive 72 hours of boiling water without failing.

The standards also test bending strength, density, and dimensional stability. Full details in the IS documents (available from the Bureau of Indian Standards).

How to check a real board

Every certified sheet carries an ISI mark with the standard number. Look for:

• IS:710 printed or stamped on the edge (BWP)
• IS:303 for BWR
• No stamp = no standard = no guarantee

When each is enough

See our guide MR vs BWR vs BWP for the decision table. Short version: BWR is fine for kitchen carcases away from the sink; BWP is required for bathrooms, wet areas, and anywhere with standing water.