Description of BS EN 16351:2021 2021

This document sets out provisions regarding the performance of characteristics of the following Types of cross laminated timber for use in buildings and bridges:

1. Type 1: Straight or curved cross laminated timber comprising only timber layers but no large finger joints;

2. Type 2: Straight cross laminated timber comprising only timber layers and large finger joints;

3. Type 3: Straight cross laminated timber comprising timber and wood-based panel layers but no large finger joints.

This document covers cross laminated timber of all three Types of cross laminated timber:

1. manufactured according to this document, which sets up provisions for:

   1. boundary conditions during manufacture of cross laminated timber;

   2. moisture content and temperature of timber to be bonded;

   3. production of finger joints and bonds between layers;

2. to be used in service class 1 or 2 according to EN 1995?1?1 ;

3. made of coniferous species and poplar listed in this document;

4. which may be made of layers made of different species;

5. bonded with phenolic or aminoplastic or moisture curing one-component polyurethane or emulsion polymer isocyanate adhesives of adhesive Type I according to the respective standard;

6. made of timber laminations having a nominal width between 40 mm (including) and 300 mm (including);

7. built up of at least three orthogonally bonded layers (at least two of them timber layers);

8. which may have, depending on the number of layers, adjacent layers bonded parallel to the grain;

9. made of timber layers which are made of strength graded timber according to EN 14081?1 ;

10. made of timber layers having nominal thicknesses between 6 mm (including) and 47 mm (including);

11. made of timber layers which may comprise edge bonds;

12. having nominal overall thicknesses up to 500 mm.

Additional provisions of this document apply for straight cross laminated timber comprising only timber layers and comprising large finger joints (Type 2):

1. made from cross laminated timber pieces having the same cross-section and layup;

2. made from cross laminated timber pieces having nominal cross-sectional thicknesses from 51 mm (including) up to 345 mm (including) and nominal minimum thicknesses of the outer layers not less than 17 mm (including);

3. made from cross laminated timber pieces solely comprising timber layers;

4. made from plane cross laminated timber pieces;

5. with parallel x-axes of the jointed components;

6. with large finger joints having a finger length of at least 45 mm and fingers which are visible at the two narrow sides of the components;

7. having large finger joints bonded with phenolic or aminoplastic or moisture curing one-component polyurethane adhesives of adhesive Type I according to the respective standard.

Additional provisions of this document apply for straight cross laminated timber comprising timber and wood-based panel layers but no large finger joints (Type 3):

1. made of structural wood-based panels specified in this document;

2. made of one panel per layer and;

3. having thicknesses between 6 mm (including) and 45 mm (including).

This document applies to cross laminated timber untreated or treated against biological attack.

This document does not cover:

1. cross laminated timber treated with fire retardants;

2. cross laminated timber which is produced from re-used timber or wood-based panels comprising re-used timber.

It also lays down procedures for assessment and verification of constancy of performance (AVPC) of cross laminated timber.

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