Formaldehyde emissions are obviously a big focus area in the wood-based panels sector. Demonstrating accurate formaldehyde emissions levels is a key requirement for wood-based panels manufacturers but this sometimes can be a lengthy process with the established methods available.
Dr Manuel Fleisch, product manager for Fagus-GreCon, told delegates at the 12th Wood-based Panels Symposium in Hamburg that this process can be significantly optimised.
Fagus-GreCon is a measurement and fire protection technology specialist with extensive experience and applications in the wood-based panels manufacturing sector.
Dr Fleisch outlined the main factory production control (FPC) methods used globally, usually fitting to regions – the US, Russia, Europe and Japan.
The commonly used method in Europe for formaldehyde analysis is wet chemistry based formaldehyde detection via photometry.
An emission test according to ISO 12460-3 using this test method takes four hours, with the photometric sample analysis taking 90mins and calculation of the gas emission value 30mins.
Disadvantages of this, Dr Fleisch said, included errors, the cumbersome testing method and that it was time-consuming. Laser infrared (IR) absorption spectroscopy (LAS) developed by Fagus-GreCon is an alternative method to use to optimise the process and works by IR laser light passing through sample gas and getting attenuated by HCHO. The gas concentration is calculated on IR-light absorption.
Fagus-GreCon’s GasAnalyser technology, using Simplelab, is a way of comparing detector and wet chemistry results directly, with continuous measurement of the formaldehyde concentration within seconds – effectively determination of the formaldehyde emission in real time.
Dr Fleisch said laser spectroscopy gives a Pbp detection limit, high calibration stability, high selectivity and no chemicals used. In addition there is easy device operation with full device control via the GA 6000 touch screen; automated calculation of gas emission values; and it is easily operatable for non-laboratory staff.
The GA 6000 can be upgraded to use with Simplelab and GA 5000 can be upgraded to GA 6000.
Basically, it is designed to give an excellent correlation for a wide range of emission levels and materials (PB, MDF, OSB).
Testing of the system has been carried out with different products at nine different locations.
A customer testing trial with Pfleiderer showed high repeatability and a standard deviation between the laser method and wet chemistry of less than 2%, with detection limit at the level of the wet chemistry.
The conclusion of testing was that LAS worked reliably at different customers and at a Farunhofer WKI trial (EN 7171-1 test chamber).
But this left the question – is there potential besides only reducing the amount of manual laboratory work?
The ambition of reducing test time to less than one hour was therefore looked at. The potential stumbling block to reach such a lofty mark is the time required to reach a stable emission level (heating time).
A way of solving this was to achieve a lower test temperature of 25°C – effectively close to room temperature. The emission level gets stable much faster at a temperature of 25°C and a relative humidity (RH) of 50%.
In fact, a test time of 15min is sufficient with these conditions. This method does not lose quality, in fact the first correlation tests to EN 717-1 and ISO 16516 reference methods show a slight increase in correlation quality.
ISO was approached to check the potential to expand the ISO 12460 standard and the results are proposed amendments of ISO 12460-1 and 12460-3.
The first amendment – regarding formaldehyde emission by 1m3 chamber method – is “the addition of a note allowing other suitable analytical procedures”, as long as they prove to give equivalent results.
This would allow the usage of state-of-the-art analysers in the future.
ISO 12460-3 amendments (gas analysis method) – proposes the addition of LAS to the list of options for analytical procedures.
The revision of ISO 12460-2 by nine experts from the US, Poland, Italy, the UK and Germany was started in March 2022 and is based on a small scale chamber method for FPC, using the 25°C test temperature and 50% RH, with LAS added to Annex C as an alternative analytical method.
GreCon says the benefits of using the new ISO 12460-2 Test Method are that it is more flexible in that it allows users of the standard to pick the test chamber volume and analytical procedure based on their personal preference and available equipment.
Also, it is reliable because real-time analytical methods can only be used if they provide identical results to the wet chemical reference methods.
It is also global because 12460-2 is based on widespread US and European test methods, meaning it should increase the global acceptance of the new standard.
Dr Fleisch summarised by saying that LAS can drastically simplify analytical procedures as described in ISO 12460-3.