LVL Handbook EUROPE

1. LVL AS A CONSTRUCTIONMATERIAL

1.12.3 Emissions and product safety

Phenolic adhesives that are cured at high temperature and

wood raw material both contain small quantities of free for-

maldehyde. In Europe, the formaldehyde emissions of LVL

products are tested according to the standards EN 717-1

(chamber method) or EN ISO 12460-3 (gas analysis method).

The Class E1 requirement according to EN 14374 correspond-

ing to ≤ 0,1 ppm (EN 717-1) can be easily achieved with LVL

products. LVL manufacturers commonly report significantly

lower formaldehyde emission levels of ≤ 0,03 ppm, and this

limit stated in the voluntary certification of some construction

product associations to demonstrate the low emissions of their

products. For example, the German Qualitätsgemeinschaft

Deutscher Fertigbau (QDF) für Holzwerkstoffe QDF-Positiv-

liste criteria states a formaldehyde limit of ≤ 0,03 ppm.

For volatile organic compounds (VOC) a European clas-

sification is currently under preparation, but for the present

different classification systems are used in different countries

either voluntarily or based on legislation. For example, in Fin-

land, LVL products are certified to show that they fulfil the M1

emission classification requirements of the Finnish Building

Information Foundation RTS for building materials. The M1

classification criteria set limit values for total volatile organic

compounds (TVOC), formaldehyde, ammonia, carcinogens

and sensory evaluation

After curing at high temperature, the adhesive bond be-

tween the LVL veneers becomes an inert polymer that does not

dissolve or react with other materials in the surrounding envi-

ronment. It is safe and non-hazardous to humans and animals.

Standard LVL products do not contain more than 0,1%

of any of the Substances of Very High Concern (SVHC) listed

in the Candidate List of the European Chemicals Agency, as

these substances are not intentionally added to the products

Manufacturers continuously monitor the Candidate List for

updates.

LVL does not contain anything classified as hazardous

waste, and has the following waste code in the consolidated

European Waste Catalogue:

- 17 02 01 Wood (Construction and Demolition Wastes)

After use at the end of its life cycle, LVL can be utilized e.g.

for bioenergy production

1.12.4 Acoustics

LVL members can be used in timber frame structures in sim-

ilar ways to other wood members to achieve the required

sound insulation levels. Sound insulation of timber structures

is usually good at high and middle frequencies if the struc-

tures have careful detailing so that they are airtight. Howev-

er, timber structures are light, which makes it challenging to

design adequate sound insulation structures against low fre-

quency sounds. Therefore, layered structures are necessary for

airborne sound insulation of intermediate walls between apart-

ments. In floor structures additional mass and resilient layers

are needed to keep the impact sound level at low frequencies

low enough.

Despite the challenges of low frequencies, real-life feed-

back from people living in well-designed wooden multi-storey

buildings has been positive. The buildings are considered silent

and the room acoustics of wooden buildings is usually regard-

ed to be comfortable. One reason for this is that the surfaces of

timber elements are less dense compared to steel or concrete,

which is beneficial for sound absorption.

Robust perforated LVL panels can be used together with

mineral wool insulation installed in cavities behind the panels

for sound absorption, e.g., in sport halls and schools. The good

impact resistance of these panels is also advantageous, e.g., in

walls of halls for ball games.

1.12.5 Fire safety

When wood burns, a layer of char forms on the wood surface.

This char layer serves as protective thermal insulation, inhibit-

ing further burning of the remaining wood cross section. This

makes the behaviour of wooden structures in fire predictable

and their resistance to fire can be calculated based on the char-

ring rates defined in EN 1995-1-2 (Eurocode 5). The one-di-

mensional charring rate β0 of LVL is 0,65 mm/min, and the

notional charring rate βn for beams and columns is 0,70 mm/

min when the characteristic density is ≥ 480 kg/m

As LVL cross sections are typically thin, with a product

thickness of max. 75 mm, they usually require additional pro-

tection to achieve the required fire resistance. This is usually

achieved with gypsum plasterboard panelling directly onto the

LVL members, or onto LVL frame structures with cavities that

are left empty or filled with mineral wool insulation. Eurocode

5 provides instructions for calculating resistance to fire.

The risk of flame spread is controlled by reaction to fire

class classifications of construction products. The class for un-

treated LVL is D-s2,d0, which is the same as solid wood, where

D is the combustibility class, s is smoke production and d is

burning droplets. The classification may be improved with fire

retardant treatments up to class B-s1,d0 for some structures,

mainly in indoor applications.

For more information about fire safety, please see Chap-

ter 6.

1.12.6 Structures for seismic areas

LVL structures can be used in seismic areas. Unless special as-

sessments are made, LVL structures are intended to be used

subject to static or quasi-static actions. In seismic areas the be-

haviour factor of LVL panels used for the design is limited to

non-dissipative or low-dissipative structures (q ≤1,5), defined

according to Eurocode 8 (EN 1998-1:2004 clauses 1.5.2 and

8.1.3 b) and to applicable national rules on construction work.

LVL structures have low weight which reduces the design

loads in seismic design. LVL-C panels are available in large siz-

es, so they can be used as robust panel bracing components to

LVL Handbook Europe