Formaldehyde has been very much on people’s minds this summer, with the Europe-wide move to expecting panels to meet E0.5 limits from August 6, 2026 under REACH Annex XVII.
You may have been wondering, what this E number is. European standard EN13986 sets limits of free formaldehyde emitted from wood based panels. Until recently this was to be E1 class emissions, and this is tested according to the chamber method, or EN 717-1. It is very different to the Total Extractable Formaldehyde (TEF) measurement which was featured in the summer edition of Technically Speaking.
Why? Well, the chamber method looks at the concentration that forms around the panels if left in a typical atmosphere – whereas the TEF test chemically extracts as much formaldehyde as possible to give a concentration per gram of panel. The two have very different uses to the scientist looking at panel performance.
Are you still wondering why this difference matters? The free formaldehyde that we’re talking about today is a much closer test to the ‘real world’ where the panels are installed in a building or a piece of furniture, or a camper van or other environment. The person sitting in their living room, or cooking in their kitchen, or relaxing in their camper van wants to know the air around them is safe. It would be reasonable to expect any VOC gases are kept below recognised limits, i.e. that if small quantities of formaldehyde migrate slowly from the panel these will not build up to troublesome levels.
As we discussed last time, the formaldehyde is chemically bound into the cross-linked resin holding the panel together. So how might it escape? The main reason is fluctuations in humidity in the air. If the air is humid then moisture from the air may lead to small amounts of hydrolysis occurring to the resin. Hydrolysis is when the water molecule reacts with the linkage in the UF resin, and breaks it. This is much more likely for urea formaldehyde resins and much less likely for phenol formaldehyde resins because of the type of chemistry present. Over time, small quantities of formaldehyde my be emitted back from the panel – however most resins are formulated to keep this as closely under control as possible. And industry may use scavengers to mop up any formaldehyde that would otherwise escape – further protecting against emission.
In our example, perhaps the fluctuations in relative humidity are small, and the air in modern houses is typically quite a low relative humidity – well ventilated, centrally heated homes are commonplace. So the other consideration is how many air changes happen per hour – i.e. if the ventilation will prevent build up of gas. As a result, in a chamber test the experiment is designed to mimic or control these two aspects. The relative humidity is tightly controlled, and the throughflow of air per hour is closely controlled too. In our labs we have a chamber which is one cubic metre in size, kept ultra clean and ready for this kind of tests. A fixed quantity of panels are introduced, and the concentration of formaldehyde is monitored over time.
The new target set under EU REACH regulations for E0.5 panels is to achieve 0.062 mg/m³ in the EN 717-1 test. This is a decrease from the long-established E1 levels in Europe, which was 0.124 mg/m³. Luckily, many resin manufacturers and panel producers have been preparing for this for many years – the technology is available and it is possible to optimise panels to meet these reduced formaldehyde levels.
