The British standard BS 1088 is the most followed marine ply standard in the world. Two versions are available now. They are BS1088:2003 and BS1088:2018. The similar standard in Australian & New Zealand is AS/NZS 2272. A similar standard in China is GB-T17657-2013. There are many plywood manufacturers claiming their products to be BS 1088 compliant. Some of them are not because we can see excessive core gaps and face veneers not thick enough.
Face Veneer Quality
- No more than 6 pin knots per square meter
- No more than 2 closed splits per meter of panel width, with a total length of 200mm
- No open splits
- No more than 2 small worm holes per square metre
- No fungal decay
- Low contrast color variation
- No repairs
- Glue penetration is only allowed near the permitted defect. Area no more than 5% of the outer ply
- Up to 5% sapwood is allowed
Face Veneer Thickness
- For 3mm ply, face veneer thickness should be 0.6-0.9mm
- For 3.6mm ply, face veneer thickness should be 0.7-1.1mm
- For ply thicker than 3.8mm, face veneer thickness should be more than 1.0mm
Core Veneer Quality
- No limit on pin knots.
- No limit on closed splits.
- On 4 edges of the marine plywood sheet, each edge only allow maximum one open splits (core gap). The open split, if any, should not be more than 0.5mm.
- Small wormholes are ok.
- No limits on edge joints.
- In the core, each square meter can not have more than 3 repairs.
- Up to 5% sapwood is allowed.
Core Veneer Thickness
Maximum thickness to be 4.8mm
Core Veneer Structure
- Adjacent plies to be laid with grains at the right angle.
- Panels less than 6.5mm should have at least 3 plies.
- Panels more than 6.5mm should have at least 5 plies.
- Center veneers can be two veneers glued together with their grains in same direction.
- Must not have core gaps, overlaps, pleats, blisters, hollows, bumps or imprints.
Permitted Timber Species
Any species which has at least a natural resistance to fungal attack as instructed in BS EN 350-2.
Standard Marine Plywood
The density of timber species should be greater than 500 kgs per cubic meters. Fungal resistance rating class 3 or better.
Lightweight Marine Plywood
The density of timber species should be less than 500 kgs per cubic meters. Fungal resistance rating class 4 or better.
- Adjacent plies to be laid with their grain at right angles.
- Minimum of 3 plys for panels less than 6.5mm thick.
- Minimum of 5 plies for panels thicker than 6.5mm.
- Not less than 40% of the grain and not more than 65% of the grain can run in any one direction.
- The panel is to be built with veneers on either side of its center line matched in thickness, timber type, cutting method, and grain direction.
- The center veneer can be made up of two veneers glued together with their grain running in the same direction.
- Must not have core gaps (but see above under core veneers permitted defects) overlaps, pleats, blisters, hollows, bumps or imprints.
The glue can be melamine-formaldehyde resin containing enough phenol to meet BS EN341-1. Or a phenolic resin. Glued edge joints are to be made with phenolic or an aminoplastic resin with a moisture resistance standard MR or better. It is highly resistant to weather, micro-organisms, cold and boiling water, steam and dry heat.
BS 1088 plywood must have a moisture content between 6% and 14% when it leaves the factory.
The BS1088-1:2003 requires the following infomation to be included.
- UNBALANCED (if the panel is constructed in an unbalanced way.
- TREATED if any rot treatment has been applied.
- the nominal panel thickness
- manufacturers name or mark
- country of manufacture
- panel type, standard or light weight
- name of the timber species
e.g. BS 1088-1:2003 MARINE/3.6mm/MD/Malaysia/LW/Gaboon