Thirteen Southern pine cross-laminated timber panels were tested in the intermediate scale horizontal furnace at the Forest Products Laboratory to determine the effects different adhesives and ply configuration had on fire performance. Four different adhesives were tested: melamine formaldehyde (MF), phenol resorcinol formaldehyde (PRF), polyurethane reactive (PUR), and emulsion polymer isocyanate (EPI). There were two ply configurations: Long-Cross-Long (LCL) or Long-Long-Cross (LLC) where “long” indicates the wood was parallel to the longer edge of the panel. The MF and the PRF prevented delamination and associated problems while the LLC configuration resulted in uneven charring patterns.
Cross laminated timber (CLT) has been developed to a worldwide well-known and versatile useable building material. Currently increasing rates in production volume and distribution can be observed. In fact CLT, thanks to its laminar structure making it well suited for use in construction, provides new horizons in timber engineering, in areas which had until now been the realm of mineral building materials like concrete and masonry.
After a short introduction, this paper aims to demonstrate current production processes used for rigid CLT. In section 2 the process steps are described and essential requirements, as well as pros and cons of various production techniques, are discussed. Latest results of R & D and of development and innovation in production technology are presented. In section 3 test and monitoring procedures in the area of the internal quality assurance, known as factory production control (FPC), are presented. Diverse regulations, in the form of technical approvals for CLT as well as in the CLT product standard prEN 16351 [1], are discussed. Additionally, some technological aspects of the product, CLT, together with a comparison of geometrical and production relevant parameters of current technical approvals in Europe are provided in section 4. In the final and main part of the paper, production and technology is presented in a condensed way. The outlook for current and future developments, as well as the ongoing establishment of the solid construction technique with CLT, is given. The product, CLT, comprises an enormous potential for timber engineering as well as for society as a whole. Standardisation and further innovation in production, prefabrication, joining technique, building physics and building construction make it possible for timber engineering to achieve worldwide success.
