Emission of Volatile Oganic Compounds from Wood and Wood-Based Materials

Appendix 3:WoodBased Products Standard Test Method for the Determination of VOC Emission

Contents

0. Preface

1. Scope, Principle and Field of Applications
1.1 Scope and Principle
1.2 Field of Application

2. Normative and Informative References

3. Definitions and Abbreviations

4. Emission Testing
4.1 Sampling from Production
4.2 Preparation of Test Specimens
4.3 Conditioning of Test Specimens
4.4 Standard Test Conditions
4.5 Measurement Times
4.6 Chemical Analysis
4.6.1 Initial analyses, optional
4.6.2 Chemical Emission Testing
4.6.3 Result of Chemical Emission Testing
4.7 Evaluation of Result

0. Preface
This standard was coordinated internationally with the work in CEN/TC 264/WG7:"Indoor air quality - Emissions of chemical substances from building materials." Concerning wood-based products the content was coordinated with Nordic Wood research institutes.

This standard specifies a general laboratory test procedure for the determination of the chemical emission of volatile organic compounds from wood-based products to the indoor air.

Test specimens (representing the product to be tested) with a known surface are placed in a test chamber with well defined and constant test conditions, including air temperature, relative humidity and air velocity parallel over the test specimen.

Gases and vapours emitted from the test specimen are mixed with the air in the test chamber. The air is analyzed by chemical analyses.

The measured emission of individual compounds are given as concentration (in test chamber) and emission rates. The emission can be converted into concentrations of individual compounds in the indoor air by use of a model room calculation.

The emission measurements are carried out under defined climate conditions in emission test chambers.

The test chamber in principle is given in Annex 1 of this standard. For further description of the chambers, chamber requirements, chamber materials etc. please refer to e.g. Ref.1.

The standards cover the following wood-based materials and products: boards, panels, floors and furniture including accessories and subsidiaries as they are delivered from the supplier/manufacturer.

The emission determined according to this standard can be used as documentation of emission from wood and wood-based materials and products to the indoor air.

This standard is based on:

3. Definitions and Abbreviations

Air exchange rate n [h^-1]

The ratio of volume of clean air brought into the test chamber hourly and chamber volume measured in identical units.

Emission

Emission of gases and vapours from a material to the surrounding air.

Emission rate R [µg/(m²h) or mg/(m²h)]

The term is in this context used as the mass emitted per time unit and area unit.

Emission profile

Curve with the concentration as function of the time.

Headspace-analysis

A method primary to determine which gases are emitted from a material. The method is used prior to the testing or at the start of the testing to identify the compounds, which the specimen emits.

Indoor climate (indoor air quality)

The air including contaminants inside rooms for human beings e.g. residences, institutions and offices. In other contexts indoor climate is often used in a wider sense.

Loading factor [m²/m³]

The ratio of the surface area of the test specimen and the volume of the chamber.

VOCs (Volatile Organic Compounds)

The VOC“s are gases under normal indoor climate conditions. The VOC's can be divided into different chemical groups:

Standard room

A fictive model room used as the basis for general calculations of indoor air concentrations for comparison of measured material related concentration with acceptable concentrations of the indoor air. The dimensions of the room and the size of the exposed surface of different building products in the room are defined in this standard.

Test chamber

The chamber can be considerably smaller than general living rooms. The test chambers have controlled climate and shall fulfil a number of requirements.

In the following test conditions and procedures on how to perform the test are given in brief. For further details please refer to e.g. Ref. 1 or Ref. 2.

Recovery studies shall include toluene and dodecane. A recovery of ³ 80% shall be guaranteed for each target compound.

The manufacturer and supplier sample the test specimen(s) directly from the production. The test specimen shall be representative for the production, the production time and the product.

The samples shall be marked with an unmistakable identification code. Solvent-based ink pens or other marking methods that may contribute with VOCs must not be used.

The specimen(s) shall be accompanied by a data sheet where the following data is to be registered:

Production week and other production data

Sampling from production of the individual wood products are stated below.

Boards

Minimum 2 boards are sampled from the production, as panels about 1 meter in length (in actual manufactured width and panel thickness) is cut from the middle of the board according to the sketch below. The panels are sealed airtight, e.g. in polyethylene foil and the sample is forwarded for testing.

Panels

Samples taken from the production are stacked and packed as panels are normally packed. The samples are forwarded for testing.

Floors

Samples are taken from the production stacked and packed as wood for floors are normally packed. The samples are forwarded for testing. Possible additives such as glue and varnish are delivered for testing in unbroken packing.

Furniture

Samples are sampled from the production and packed as normal prior to shipment.

The furniture is forwarded for testing.

The laboratory will adjust the test specimen area in relation to chamber volume in order to obtain the required load. A ratio of n/L = 1, where L = loading factor and n = air exchange rate is recommended.

For wood products, where the emission is expected to vary within the test pieces and from wood piece to wood piece, the following shall furthermore be registered when possible: Relative surface area of hardwood/sapwood and knots for the area of the individual test specimen which is exposed in the chamber.

Preparation of test specimens for the individual wood products are stated below.

Boards

Test specimen for emission testing will be sampled as shown on the sketch below.

The edges of the test specimens are sealed airtight by use of low emitting aluminum tape.

Panels

Test specimens for emission testing are sampled from the middle of the package.

Floors

Test specimens for emission testing are sampled from the middle of the package.

When testing parquet floors the parquet rods and boards are joined together according to the guidelines of the manufacturer/supplier. Test specimens for emission testing are cut according to the sketch below:

As a principal rule wooden floors are tested including the glue recommended by the manufacturer. Type of glue, description, brand, application method, application time and amount etc. are stated. To obtain conditions as close as possible to reality between jointings and surface, the test specimens for testing are cut, so that the width of the parquet rods (shortest side) makes out the longest side of the test specimen.

Testing of a varnish for treatment of floors is generally based on testing of the varnish coated on a wooden substrate. The substrate, application method, applied amount, number of coats, intervals between coating etc. follow the guidelines given by the manufacturer/supplier.

Furniture

As a principal rule furniture is tested so complete as possible and the emission from all materials are measured during the same chamber exposure that means including additives e.g. lacquer and oils, accessories e.g. hinges.

If it is necessary to cut up a piece of furniture, then all the cut edges should be sealed airtight with aluminum tape or foil.

When sampling parts of furniture, the relative area between the individual materials/material compositions has to be the same as that of the furniture in full size.

A miniature piece of furniture can be tested joined together as one object or in several parts, as long as the testing takes place by the same chamber exposure. If a test specimen is tested in several parts, then normally adjacent areas are sealed prior to exposure.

Surfaces and edges which in practice are untreated are as a principal rule tested without sealing, while surfaces and edges which in practice are surface treated are tested with the actual surface treatment. In cases where it in practice is hard to perform the actual surface treatment e.g. a cut edge, the edge in question could be sealed with tape. In this case the edge area sealed with tape does not form part of the area calculation.

The test procedure is initiated not later than 4 weeks after date of production. From the time the product is released from the manufacturer for sale to start of testing, the samples are stored in unbroken packing at the laboratory at normal room temperature. If the original packing is not air tight, the sample should be packed in emissionfree plastic, e.g. polyethylene foil.

If the samples have not been prepared immediately before the testing, they will be stored in emissionfree plastic at room temperature.

During the total conditioning period the test specimens kept at the standard test conditions, see part 4.4 Standard test conditions.

4.4 Standard Test Conditions

Standard test conditions:

4.5 Measurement Times

The time 0 is defined as the time when the packing is opened and the test specimen is placed in the test chamber.

Regarding products with an unknown emission profile the emission is determined over a period of at least 28 days with sampling in at least 3 periods after e.g.:

Additional measurements should be agreed upon in the individual cases.

The mean between the starting and closing time of sampling is used as the measuring time. Measuring-intervals depend on kind of chamber and test conditions.

There are no universal calculation models for determination of the emission profile.

4.6.1 Initial analyses, optional

Formulas, samples of materials/components etc. are given as supplementary information to the laboratory.

For unknown samples an initial qualitative headspace analysis could be carried out in order to determine the programme for analyses including selection of the gases and vapours, on which the evaluation is based.

The analysis programme is determined according to the detailed objective of the testing, considering as a minimum the following types of VOCs including:

4.6.2 Chemical Emission Testing

Chemical emission measurements include as a minimum:

The detection-limit for individual VOCs should be aimed at approx. 1 µg/m³ (test chamber concentration). All individual VOCs in concentrations in the test chamber) over 5 µg/m³ and compounds selected for determination should be identified.

4.6.3 Result of Chemical Emission Testing

The measured emission of individual compounds are given as concentration (in test chamber) and emission rates.

The emission can be converted into concentrations of individual compounds in the indoor air by use of a model room calculation according to Ref. 2, Ref. 3 and Ref. 4.

A test report should as a minimum contain the points given in Annex 2.

The reported results can be used in declarations. The results can e.g. be converted to time-values by comparing model room concentrations and threshold values for the individual compounds of concern.

ANNEX 1 LOOK HERE

Annex 2

A test report should as minimum contain the following:

Name and address of the testing laboratory
Unique identification number of the test report
Name and address of the assignor
Purpose of the test

Description and identification of the test objects, a.o.:

Date of unpacking
Date for receipt of the test objects.
Method of sampling.
Ageing and conditioning of test specimens.
Date for start and closing of the testing.
Description of test methods and test procedures.
Description of test chambers including type and test conditions.
Description of other equipment.
Any deviations from the test method

Measurements, assessments and concluded results a.o.:

Inaccuracy and uncertainty of the test results

Date and signature of the person who is technically responsible for the report.

Statement whether a result only relates to the examined specimen.