Much of what our rooms are equipped with contributes to “poor” indoor air quality. The assessment of indoor air quality based on measurements of construction products in the so-called test chamber should be carried out according to standardized guidelines, just like the measurement of indoor air in finished rooms, in order to ensure the comparability of the results.
Text and photos Caterina Dawid
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What is indoor air quality?
The term considers those aspects of indoor air that have an impact on people’s well-being, health and productivity. According to a survey by the German Federal Environment Agency, people in Germany spend an average of 80 to 90 % of their lives indoors and breathe in between 10 and 20 m³ of air per day, depending on their age and activity level. This corresponds to a mass of 12 to 24 kg of air. Annex A of ÖNORM EN ISO 16000-1 [1] lists the most important types of indoor spaces and the sources of air pollution frequently encountered in them.
In general, people, building materials, furnishings, renovation materials, cleaning agents, products containing biocides such as disinfectants or preservatives, ventilation and air conditioning systems, outdoor air and heating appliances are cited as examples of emitting sources. However, cooking processes, tobacco smoke, fireplaces, cosmetics, hobby work or toys can also be a source of air pollution.
The following non-exhaustive list of the most frequently detected substances shows which components can come from which sources:
- Impurities generated by the user’s body (humans and pets):
- very volatile substances such as acetone and alcohols,
- from deep fryers, open fires and tobacco smoke: acrolein, benzene, polycyclic aromatic hydrocarbons (PAH),
- from dyes, paints, coatings or wood preservatives: toluene, terpenes, pinene, limonene and medium to low volatile halogenated hydrocarbons such as lindane or pentachlorophenol,
- from chipboard, furniture, open fires, tobacco smoke, insulating materials and disinfectants: Formaldehyde.
Guidelines for indoor air quality
While limit and guideline values according to the Technical Rules for Hazardous Substances (TRGS) apply to workplaces where hazardous substances are handled, this does not apply to rooms. The maximum workplace concentration (MAK) known from occupational health and safety is not used to assess indoor air.
Austria has a guideline value for each pollutant, the WIR (Wirkungsbezogener Innenraum Richtwert), which is set by the Indoor Air Working Group at the Ministry of the Environment together with the Academy of Sciences. An indoor air guideline value represents the concentration below which, according to current knowledge, there is no harmful effect on humans. [2]
As construction products can contribute significantly to indoor air pollution through their emissions, the Committee for Health-related Evaluation of Construction Products (AgBB) has developed test and evaluation criteria and published an evaluation scheme for VOC emissions [3]. The AgBB is based at the German Federal Environment Agency. The requirements for indoor air quality in buildings (2021 edition) state: “Indoor air quality in occupied rooms that is acceptable in terms of health must be ensured by limiting the substance loads from construction products.” Furthermore, reference is also made to ÖNORM EN 16516 [4] as a building authority verification procedure for the assessment of emissions of volatile organic compounds. The emission of substances from construction products is highly dependent on the conditions under which these construction products are tested. The air temperature, relative humidity, air exchange rate and air velocity in the chamber, as well as the quantity or surface area of the material, have a decisive influence on what and how much is found.
The Association for Low-Emission Flooring Installation Materials, Adhesives and Construction Products has also issued a test seal, the Emicode® seal, which also names different emission categories. The tests required for the award of the Emicode® seal must be carried out exclusively by laboratories that have mastered the defined GEV test method and whose accreditation in accordance with ÖNORM EN ISO 17025 [5] also includes tests in accordance with ÖNORM EN 16516. The normative basis for the examination is therefore ÖNORM EN 16516 and ÖNORM ISO 16000 Part 9 [6] to Part 11 [7].
Standards, what for?
Standards are created with general approval and adopted by recognized standards institutions. They are the basis for the standardization of processes. Therefore, the results of the tests are comparable if they were carried out in accordance with the cited standards, even if they were performed by different testing institutes. The Emicode® seal goes one step further with regard to the comparability of different testing institutes, which also requires accreditation in accordance with ÖNORM EN ISO 17025. Accreditation in accordance with ÖNORM EN ISO 17025 is a highly valued proof of competence at national and international level and ensures that the analysis results are credible, correct and comparable. Accreditation guarantees that work is always carried out in accordance with the latest standards or guidelines and that the quality of the tests is monitored. A very important instrument for monitoring quality is participation in interlaboratory comparisons, which is mandatory for an accredited company. Several laboratories receive an identical sample, which must be analyzed under specified (standardized) conditions. The results are processed statistically and thus the measurement accuracy of the laboratories is evaluated.
Checking the indoor air quality
Indoor air quality can be measured in two different ways:
- The investigation of emissions from building products before installation in the rooms
- The examination of indoor air in new buildings, renovated or newly equipped rooms
Chamber examination
Sampling and sample transportation have a major influence on the results. As volatile substances are to be determined, ÖNORM EN ISO 16000-11 regulates the point at which the sample is to be taken, e.g. from a meter of material, but also the way in which the sample is to be packaged so that not too many of the substances to be tested can disappear during transport. The handling of liquid samples is also regulated in this section. As the emission chamber is a model room, the size of the test piece also has an influence on the emission results. This is specified in the so-called loading factor and should correspond to the ratio in a real room.
ÖNORM EN ISO 16000-9 regulates the conditions in the chamber, such as temperature and relative humidity and also the so-called air exchange rate. According to ÖNORM EN 16516, the test climate must be recorded at intervals of 30 minutes and the average temperature in the test chamber must not deviate too much from the target value. The air sampling itself and the analytical methods for determining the volatile substances (VOC) are regulated in DIN ISO 16000-6 [8], ÖNORM EN ISO 16017 [9] and ÖNORM EN 16516.
Air sampling is carried out by means of pumps from the chamber exhaust air directly onto sampling tubes. Here it is particularly important that the pump draws in an exact volume of gas and can also indicate exactly how much has been drawn in, as the analysis results are converted from the sample volume to m³. The sampling tubes hold the analytes so that they can be taken to the analysis laboratory. The sampling tubes are filled with so-called sorbents. Not all sorbents are suitable for all tasks. The standard ÖNORM EN 16516 describes some sorbents and also specifies their area of application.
Indoor air measurement in accordance with ÖNORM EN ISO 16000 Part 5
If you want to test the indoor air quality in a new building that is ready for occupancy or a newly renovated room, ÖNORM EN ISO 16000-5 [10] specifies what needs to be observed in the run-up to such a measurement. As the sampling and preparation of the rooms for sampling have a greater influence on the accuracy of the measurement results than the actual analysis, particular care must be taken here to ensure a regulated and standardized procedure. The standard also addresses differences in the ventilation of rooms – rooms with and without ventilation systems are described.
The illustration shows a typical setup for sampling room air. Two pumps can be seen here, each drawing the room air through two sampling tubes. Here, too, it is important to know the exact sample volume drawn in. The substances captured on the tubes are analyzed in the laboratory.
Analysis of the air samples taken
The analysis is carried out using state-of-the-art equipment; ÖNORM EN ISO 16000-3 [11], ÖNORM EN ISO 16000-6 and ÖNORM EN 16516 specify the analysis systems. With one analysis, around 200 individual analytes can be identified and their quantity in the air sample taken can be determined if it is more than 5µg/m³. The substances are identified via so-called spectrum libraries or via the measuring system itself, while the quantity of the analytes is determined by calibrating the system. Here too, quality assurance is specified by the standards: Participation in round robin tests, determination of blank samples, checking the system with so-called reference substances.
Bibliography and list of standards
[1] ÖNORM EN ISO 16000-1: Indoor air contaminants. Part 1: General aspects of the sampling strategy, June 1, 2006.
[2] Tappler, P.; Moshammer, H.; Hutter, H-P.: Gesunde Raumluft in Arbeitsräumen, (PDF) WEKA Verlag GmbH.
[3] Committee for Health-related Evaluation of Building Products (AgBB): Requirements for indoor air quality in buildings: Health assessment of emissions of volatile organic compounds (VVOC, VOC and SVOC) from building products, (PDF) Umweltbundesamt Deutschland, 2021.
[4] ÖNORM EN 16516: Construction products: Evaluation of the release of dangerous substances – Determination of emissions to indoor air, January 15, 2021.
[5] ÖVE/ÖNORM EN ISO/IEC 17025: General requirements for the competence of testing and calibration laboratories, February 15, 2018.
[6] ÖNORM EN ISO 16000-9: Indoor air pollutants. Part 9: Determination of the emission of volatile organic compounds from building products and furnishing – Emission test chamber method, December 15, 2011.
[7] ÖNORM EN ISO 16000-11: Indoor air pollutants. Part 11: Determination of the emission of volatile organic compounds from building products and furnishing – Sampling, storage of samples and preparation of test specimens, June 1, 2006.
[8] DIN ISO 16000-6: Indoor air pollutants. Part 6: Determination of organic compounds (VVOC, VOC, SVOC) in indoor air and test chamber air by active sampling on adsorption tubes, thermal desorption and gas chromatography with MS or MS-FID, March 1, 2022.
[9] STANDARD EN ISO 16017: Indoor air, outdoor air and workplace air – Sampling and analysis of volatile organic compounds by sorbent tubes/thermal desorption/capillary gas chromatography. Part 1: Sampling with a pump, June 1, 2001.
[10] ÖNORM EN ISO 16000-5: Indoor air pollutants. Part 5: Sampling strategy for volatile organic compounds (VOC), June 1, 2007.
[11] DIN ISO 16000-3: Indoor air pollutants. Part 3: Measurement of formaldehyde and other carbonyl compounds in indoor air and in test chambers – Sampling with a pump, December 1, 2023.
[12] ÖVE/ÖNORM EN 45020: Standardization and related activities – General terms, 1 February 2007.
