Bending properties have been determined by mechanical testing [modulus of elasticity (MOE) and modulus of rupture (MOR)] and by means of longitudinal (L) and transverse (T) vibration nondestructive methods on 150 sawn timber pieces of Pinus radiata D. Don, with the dimensions of 80 × 120 mm cross-section and 2500 mm long, from Catalonia, Spain. The fundamental vibration frequency was measured by recording the sound produced by hitting the piece in L and T directions, and this signal was analyzed by fast Fourier transform sound analyzer. The dynamic MOE was obtained for both procedures and compared with static MOE and MOR. The notion of concentrated knot diameter ratio (CKDR) was introduced to improve the prediction of MOR. CKDR gives better results when this parameter is referred to the central portion of piece length. Both methods (L and T frequencies) have similar accuracy in prediction of mechanical properties, but the first one is simpler and has some practical advantages. The timber graded with this nondestructive method offers better results than the visual grading rules for the same output.

Boron‐based formulations are used to improve the service life of timber. On the one hand, boron‐treated wood increases resistance to biological attacks (e.g. by fungi and insects), and on the other hand, it renders wood more resistant to burning. In the present study, we analyse the fire behaviour of some water‐borne formulations containing boron. A completely inorganic formulation (disodium octaborate tetrahydrate (DOT)) is compared with new‐generation tannin‐based wood preservatives in which the flavonoid network is used to fix the boron to wood. The study of the fire behaviour was carried out according to four specific fire tests: (i) dripping; (ii) short‐term exposure; (iii) long‐term exposure and (iv) the limiting oxygen index. The Scots pine (Pinus sylvestris L.) specimens treated with DOT have shown a complete efficacy against fire after all tests were completed. It should also be noted that very positive results have also been achieved by the tannin‐based solutions. DOT has to be preferred when high performance is required, but exclusively for interior applications. The use of tannin‐based formulations can be suitable for outdoor fire protection and also for indoor applications when specific aesthetic requirements should be fulfilled. Copyright © 2013 John Wiley & Sons, Ltd.

1The effect of epsomite as flame retardant for wood has been investigated and compared with a

Wood is a widely used material in the construction sector, both in structural and nonstructural applications. Tropical species are appreciated for their high quality and durability in furniture, outdoor and indoor claddings and floors. However, limited information exists about fire reaction of tropical wood. Density is one of the factors that influence the rate of pyrolysis reactions and consequently the charring rate. However, other wood characteristics such as the mineral content also exert an influence on the pyrolysis combustion of wood. Hardwoods present a complex morphological structure and a significant amount of minerals, extracts and exudates. In this work, we study the fire reaction of seven species of tropical hardwood using various fire tests. Results are compared from one test to other one and are discussed in relation with physicochemical properties of wood species. The results show that although there is some correlation between high density and ignition time, parameters such as morphology and mineral content are also relevant.

The use of large cross-section timber for structural purposes has increased in Spain, and knowledge of its properties is strategically necessary. The Spanish visual strength-grading standard UNE 56544 (2011) efficiency applied to large cross-section structural timber was analyzed using a sample of 363 specimens of radiata pine (Pinus radiata D. Don.) from the Basque Country and Catalonia, Spain. Different sizes were tested (80 × 120 × 2400 mm ). Bending strength, modulus of elasticity, and density were obtained, and characteristic values were determined in order to assign strength class according to European standard EN 338 (2010). Knots and twists were the most relevant singularities for visual strength grading. It was concluded that large crosssection Spanish radiata pine timber was suitable for structures, and it was assigned to the C20 strength class.