Formaldehyde - test methods
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- A formaldehyde content test produces information on, how much formaldehyde is in the product.
- A free formaldehyde content test tells about how much formaldehyde can be released during lifetime of the product.
- An emissions chamber test shows the contribution of the product to indoor formaldehyde air concentration after a certain elapsed time.
- Some liquid products contain preservatives in bounded form from which formaldehyde is released slowly until the product is spread out on a surface.
- Total formaldehyde tests set free all potentially formed formaldehyde at once.
- Free formaldehyde determines actual formaldehyde concentrations in the product.
- The details of the testing protocol (pH value, extraction agent etc.) determine to which extent formaldehyde is captured and analyzed, or hidden, with such testing methods.
- Case 1:
If formaldehyde is brought into the product and diffuses out slowly, then the normal VOC emissions test protocols can be applied to formaldehyde accordingly. Just the air sampling and analysis method has to be specific for formaldehyde (e.g. the acetyl acetone method, as in EN 717-1) or for volatile aldehydes in general (the DNPH method, as in TS / EN 16516, ISO 16000-3, CDPH method, ASTM D5197 and more).
An emissions chamber test shows the contribution of the product to formaldehyde air concentration after a certain elapsed time - in Europe after 3 and/or after 28 days, and in the USA after 14 days, or after 7 days for furniture, or after 20 hours for wood-based panels in a large test chamber. All these approaches serve as indicator for long-term indoor air exposure.
- Case 2:
If formaldehyde is produced continuously, e.g. by hydrolysis of a binder in contact with normal air humidity, then a steady-state-concentration will be reached in a test chamber, typically after some days or weeks. Several test methods determine the steady-state-concentration by taking air samples almost every day to establish the decay curve. Then it is calculated which concentration will be the stable one, and when this will be reached, from that decay curve (EN 717-1, ISO 12460-1, ASTM D6007).
In most cases, the steady-state-concentration and the emissions test result after 28 days correlate well, as long as the testing parameters are similar.
- Air humidity:
- Loading factor
EN 717-1 (which is the basis of E1 formaldehyde class), in comparison with TS / EN 16516 and ISO 16000, operates with
- the same testing temperature;
- 1.0 air change per hour (EN 717-1) instead of 0.5;
- a fixed loading factor of 1.0 (EN 717-1), instead of loading factors depending on the application scenario, such as floor, wall etc.;
- and EN 717-1 prefers air sampling and monitoring with the acetyl acetone method, but it allows the use of the DNPH method (ISO 16000-3 and TS / EN 16516) as well, as these are known to be equivalent for formaldehyde.
Yes and no.
It cannot be used if you read the letters of the standards alone, because TS / EN 16516 and ISO 16000 do not determine the steady-state concentration.
But TS / EN 16516 and ISO 16000 test results obtained after 28 days can be used if the following considerations can be accepted:
Also here, it is possible if the following considerations can be accepted:
- The ventilation rate during testing is close to EN 717-1 ventilation rate for all these standards.
- Some US standards (ASTM E1333, ASTM D6007) operate at a higher test temperature than the other standards which gives higher test results (25 °C versus 23 °C in Europe).
- Several of the US standards (ASTM D5116, ASTM D6670, CDPH, ANSI/BIFMA M7.1) have a shorter testing duration than EN 717-1 (which goes for testing until equilibrium, but not longer than 28 days). This may lead to higher test results if equilibrium is not reached when the US test was stopped.
A number of simpler tests are in use for daily factory production control, and sometimes even for evaluation of formaldehyde product emissions:
- Gas analysis: EN 717-2, ISO 12460-3;
- Flask test: EN 717-3;
- Perforator test: EN 120, ISO 12460-5;
- Desiccator test: ISO 12460-4, ASTM D5582, JIS A1460.
If a manufacturer needs formaldehyde and VOC emission testing for markets in several countries, then Eurofins can try to help saving money by combining all required testing into one test setup, and by selecting the worst-case test method to obtain test data covering all requirements. This service is unique in the whole world. No single other testing laboratory is approved for emission chamber testing by the same number of both US and European specifications and regulations for low-emitting products.