10. BS EN 636 - Plywood specifications

(Has replaced BS 6566 Part 1 - Specification for construction of panels and characteristics of plies including marking)

Dry - for interior applications with no risk of wetting, defined in hazard class 1, with a moisture content corresponding to environmental conditions of 20° C and 65% relative humidity (12% mc or less).

Humid - for use in protected exterior applications as defined in hazard class 2, with a moisture content corresponding to environmental conditions of 20° C and 90% relative humidity (20% mc or less).

Exterior - for use in unprotected external applications, as defined in hazard class 3, where the moisture content will frequently be above 20%.

See Table 1 of this document.

A new clause 4 classifies plywood on its bending properties. This classification is independent of the plywood's composition factors such as species, no of plies, thickness of plies etc. The respective bending strength class F given in Table 1 and the respective bending modulus class E given in Table 2 of EN 636 can be used to obtain the characteristic value for that particular plywood grade as appearing in prEN 12369-2: Wood-based panels- Characteristic values for structural design Part 2-plywood.

All three parts of BS EN 636 also include references to other standards and properties that may be required of panels in each category. These include:

• Dimension tolerances - EN 315
• Characteristic values for structural applications - EN 1058 & EN 789
• Bending properties - EN 1072
• Mechanical properties for non-structural applications - EN 310
• Formaldehyde class - EN 1084

Panel Marking:- Each panel will be marked with the following details:-

• Manufactures name, logo or code
• EN 636 and the conditions of use ( dry), (humid) or (ext)
• Type of panel
• Nominal thickness
• Third party certification body if appropriate

(APA plywood manufactured to PS1-95, PS2-92 and PRP-108 complies with this standard and therefore is eligible for consideration in Eurocode 5.)