What IS 710 (BWP marine plywood) is
IS 710 is the Bureau of Indian Standards specification for boiling-waterproof marine plywood. The veneers are bonded with a 100% phenol-formaldehyde (PF) glue line and built on a hardwood core, so the board survives prolonged immersion, steam and humidity without delaminating. It is the grade for boatbuilding, hulls and decks, constantly wet interiors and exterior marine joinery.
What IS 303 (commercial plywood) is
IS 303 is the specification for general-purpose commercial plywood. It is classified into two grades by water resistance:
- BWR (Boiling Water Resistant) — fortified glue line (melamine-fortified UF or PF), for kitchens, semi-humid and semi-exterior use.
- MR (Moisture Resistant) — urea-formaldehyde bonded, for dry interiors, furniture and panelling.
The common confusion is BWR vs BWP. BWR resists boiling water; BWP is waterproof. They are not the same grade — BWP (IS 710) is the higher, marine specification.
IS 710 vs IS 303 at a glance
| Attribute | IS 710 — BWP | IS 303 — BWR | IS 303 — MR |
|---|---|---|---|
| Grade | Marine / boiling-waterproof | Boiling-water-resistant | Moisture-resistant |
| Glue line | 100% phenolic (PF) | Fortified UF / PF | Urea-formaldehyde (UF) |
| Water resistance | Highest — withstands immersion | High — withstands occasional wetting | Moderate — humidity only |
| Typical use | Boats, decks, constant wet | Kitchens, bathrooms, humid areas | Furniture, dry interiors |
| Relative cost | Highest | Mid | Lowest |
How to choose
Match the grade to how much water the panel actually meets — over-specifying wastes money, under-specifying delaminates:
- Constant water / marine → IS 710 BWP.
- Occasional water (kitchen, bathroom, humid climate) → IS 303 BWR.
- Dry interior furniture and panelling → IS 303 MR.
For an exterior concrete-formwork panel you usually want film-faced shuttering plywood (IS 303 BWR core with a phenolic film), not bare marine ply — see film-faced shuttering plywood.
How to verify a grade
Look for the BIS standard mark and the grade stamp on the panel, ask for the test certificate, and — for marine — confirm the glue line passes the boil test. A genuine IS 710 board holds its bond after hours in boiling water; a mislabelled commercial board will not.