The environmentally friendly nature of bamboo is well known, but what about the processes that turn the raw stalks into those products you see on the shelves? Bamboo is actually a type of grass, and to turn it from hollow, round sticks into a uniform material that you can make something out of requires separating the fibres or splitting the stalk, and gluing them together in different ways. Many wood products use glues to turn them into a uniform and stronger material, including Oriented Strand Board (OSB) and plywood used in construction, and the ubiquitous MDF (Medium Density Fibre-board, which is between 15 and 30% glue). As with everything some glues are better than others and as always there is a trade-off between cost, the environment and performance.
The most common timber glues are based on phenolic resin and urea-formaldehyde. Both contain formaldehyde (H2CO) which at high doses is toxic to humans, and a known carcinogen. Therefore formaldehyde emissions from glues need to comply with the formaldehyde emission standards for safe exposure levels. The glues are rated on the 5-level international E-scale, from E3 as the worst, to Super E-0 as the best. E0 is the level of emissions we are often exposed to as part of our natural environment. Want to know more detail about formaldehyde off-gas from building products, check out this article from weemakechange.co.nz
It has taken us 4 years of working with our bamboo supplier to get to the stage where we are happy with our wonderful bamboo plywood. Our final product is custom made from 5 layers of bamboo veneer, held together with a water based Super E-0 glue.
So how can we be sure that we really have Super-E0 glue? As we are working with our plywood every day, we wanted to be sure that we weren't being exposed to high levels of formaldehyde. Engineered wood products naturally off-gas H2CO, but the process of cutting them emits much more than the background levels. We invested in a special air quality meter, calibrated to test for airborne formaldehyde and volatile organic compounds (VOC). We use it to check our incoming shipments of bamboo, and also run it regularly inside the laser cutter to measure the emissions during the cutting process. The first picture below is one of our typical formaldehyde test readings, on a newly unloaded shipment of plywood. The latest EU safe working limit is 0.3 (ppm), as you can see we are at less than 0.7% of that limit!
It's great to be able to continuously improve our products, as we ourselves learn more and dig deeper into each aspect of what we do.