FAQs concerning the horizontal EU testing method CEN/TC 351

You cannot find your question concerning the harmonised testing method? You would like to know more about the CEN/TC 351? Do not hesitate to contact us!

What kind of requirements for construction products in terms of their VOC emissions are applicable in Europe today?


"The construction works must be designed and built in such a way that they will, throughout their life cycle, not be a threat to the hygiene or health and safety of workers, occupants or neighbours, nor have an exceedingly high impact, over their entire life cycle, on the environmental quality or on the climate during their construction, use and demolition, in particular as a result of any of the following: the emissions of dangerous substances, volatile organic compounds (VOC), greenhouse gasesor dangerous particles into indoor or outdoor air (cf. also Annex I "Basic requirements for construction works", No 3 "Hygiene, health and the environment").

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What is the reason for a new horizontal method of testing?

  • The harmonisation of the modus operandi during emission testing is to ensure the reproducibility and reliability of test results of different laboratories.
  • The prevalent testing method of the ISO standard series 16000 is too imprecise in certain fields, especially in terms of the sample preparation. The new harmonised testing method bases on the ISO 16000 but has been complemented by further specifications.

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What will be different due to the harmonised testing method?


  • The most relevant alteration will be the definition of the European reference room as reference value for calculation of test results in terms of their impact on the indoor aor concentration. This reference room is mandatory for all products and purposes of use. It will be specified bigger than in the context of ISO 16000 (Sizes and more details please see here).
  • Additionally further specifications for sampling and sample preparation have been stipulated (More details please see here).
  • The harmonised testing method defines tighter variation values of air change rate and factor of loading (More details please see here).

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What will stay the same despite of the new testing method?

  • Alongside with the new harmonised testing method the existing method for formaldehydes EN 717-1 will continue to be effective due to existing regulations for the determination of formaldehyde equilisation for wood-based materials.

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For which products is the testing method applicable?

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Does the harmonised testing method stipulate limit values for VOC emissions from contruction products?


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What impacts on existing legal regulations will the new harmonised testing method will have?

  • The future aim is to substitute the national approvals by the CE marking. After the publication of the harmonised testing method as EN standard, a VOC emission classification comparable to the French VOC label is to be launched.
  • All existing national regulations (Ü mark, French VOC A+ label, Belgian regulation etc.) will then take up the CE classifications and determine which level of classification they want to apply.

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How will the sampling and the sample preparation be handled in the harmonised testing method?


  • Sampling off production: as early as possible (according to ISO 16000) but no earlier than at that point of time when the product is ready for shipping to the customer or provider, so drying and hardening processes at production site can be considered.
  • Selection of sample has to be representative for the whole volume of production.
  • Random sampling: selection either of common sample or of worst case sample.
  • Airtight packaging of sample: as early as possible but in any case on the same working day when it was sampled off the production.
  • Safe transport to testing laboratory and avoidance of extreme physical and thermic circumstances.
  • Arrival of sample at laboratory: 14 days after sampling the latest.
  • Start of testing: 8 weeks after sampling the latest (after 4 months after sampling if bottled liquid product). Usually the eco-INSTITUT starts testing after 1 week after arrival of sample.

Sample preparation and conditioning

  • Materials being mostly exposed to the indoor air via their surfaces (e.g. floor covering) are taped (airtight) at their edges and backsides.
  • Liquid samples (e.g. varnishes and adhesives) are applied onto carrier materials (e.g. glass or metal).
  • Liquid samples that need to dry are preconditioned in a seperate chamber having the same climate and airing conditions as the test chamber.
  • After conditioning the sample is immediately transferred to the test chamber. 

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In how far will the conditions of the test chamber change due to the harmonised testing method?


  • In terms of the ISO 16000-9 the reference room and the factor of loading will be different. The conditions, however, correspond with those of the AgBB scheme respectively the requirements of the principles of the German Institute of the Structural Engineering (DIBt) and those of the French VOC A+ regulation.
  • Reference room
    • Determination of an European reference room being mandatory for all products and purposes of use.
    • This reference room is no test chamber, it only serves as reference value for evaluation of test results in terms of their impact on the indoor air concentration.
    • The test chamber simulates the parameters of the reference room.
    • Sizes of the reference room:
      • Area 3 x 4 m (12 m2)
      • Height 2,5 m
      • A door 2 x 0,8 m (1,6 m2)
      • A window 2 m2 
      • (in comparison: ISO 16000-9: area 7 m2, height 2,49 m)
  • Parameter of test chamber
    • Temperature: 23 ± 1 °C
    • Relative humidity: 50 ± 5%
    • Air change rate/h: 0,5 (deviation 0,25 - 1,5)
    • Loading
      • Floor, ceiling: 0,4 m2/m3
      • Walls 1,0  m2/m3
      • small surfaces (e.g. a door): 0,05 m2/m3
      • very small surfaces (e.g. sealants): 0,007m2/m3
      • (deviation: ± 50% (max. 2,0))
    • Air velocity on the surface: 0,1 -0,3 m/s
    • Size of test chamber: depending on sample 20 l minimum
  • If the designated operating conditions offer the possibility a product may be applied onto more than one of the abovementioned surfaces, the according areas and factors of loading may be added up or the largest surfaces and loading factors applicable may be used depending on the existing stipulations of national regulations.

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How will the chemical analysis take place in the harmonised testing method?


  • Analysis of test chamber air after 3 and 28 days (according to ISO 16000-9), a shorter duration of testing possible if the 28 days limit values are met earlier (but: early termination is determined in the according product standards; cf. measurement of DIBt may be terminated after 7 days the earliest).
  • Adsorbents: tenax TA for VOC and SVOC; DNHP for volatile aldehydes and further carbonyle compounds (equal to ISO 16000-3 and -6).
  • Determination limit for VOC analysis 1 µg/m3, lowest reliable evaluation limit: 5 µg/m3 (equal to AgBB/DIBt, AFFSET).
  • Definition of TVOC as total of all VOC in the range from N-hexane to N-hexadecane on a 100% nonpolar GC column (equal to ISO 16000-9).
  • NEW! The gaschromatic/massspectormetric (GC/MS) analysis is performed with only one kind of detector (MS) and only one kind of separation column
  • NEW! Appliance of a lightly polar gaschromatically graphic separation column for single substance analysis; thus a better separation of complex mixtures with polar VOCs (in ISO 16000-6 a 100 % nonpolar separation column is applied).
  • Double air sampling and analyses are necessary, back up sampling, however, are not envisaged. 
  • Restriction of air sampling volume up to 5 litres max. in order to avoid VOC losses.

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Are my existing test results still applicable?

  • All test results in compliance with the harmonised testing method can still be used (e.g. results of testing according to AgBB/DIBt or to the criteria of the French VOC A+ label).
  • New tests are not necessary if the 'old' ones cover the preliminaries of the harmonised testing method, e.g. the measuring points of time after 3 and 28 days.

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