ENVIRONMENTAL SAFETY ISSUES
The preferred method for the removal of lead based paint, documented around the World, is to use water to eliminate the dust caused by dry sanding. The capture and containment of the liquid waste is also equally important. The Alderson Electric Sanders meet or exceed these documented Standards. We have mechanised the wet sanding standard. This means that the toxic waste simply runs down the vertical walls and is then captured in our Enviromat. It is in the waste capture that we exceed the Standards. The Standards envisage that plastic sheets are used to capture the waste. The problem is that plastic sheets allow the water and the waste to run off, ending up soaking into the ground. Our Enviromats are made from a woven synthetic material that lets the water through but captures the lead waste. Our tests have shown that we capture 99.2% of the lead waste and that 0.08% can go through the Enviromat. This is because the material that goes through the mat is very very fine. Putting all this into perspective though, the test results show that we captured 2,500 parts per million and the Enviromat allowed only 20 parts per million through the mat. The soil contamination standards are set by local Councils but most are fairly consistent. The allowable soil contamination around a kindergarten for example is 200 parts per million and in commercial areas it can be as high as 500 parts per million. So what lead that can pass through our Enviromats, is well inside generally accepted “allowable” limits. In addition to all this, because the waste from our system is localised, that is it runs down the wall rather than be blown everywhere, our 20 parts per million ends up around the basement area of the property being sanded. We use a minimal amount of water, just enough to lubricate the disc, at 1-2 liters per minute.
The second preferred method outlined in the NZ Standard involves the traditional removal of lead paint using toxic paint stripper, scraping and capturing the waste on plastic sheets. This is followed up by sanding the residual paint off using a dry sander with a vacuum and HEPA filter. Tests in the USA have shown that this sanding / vacuum process does not capture all the lead waste from the dry sanding process. It is better than nothing, but it is estimated that this process will capture only 60-70% of the dust waste – that is why in some States in the USA, the sanding machines have to be limited to no more than 1,500 rpm. The waste, captured in the plastic sheets, can also easily be disbursed in windy conditions and get blown all over the place. Some States in Australia ban the use of dry sanding if the wind is even likely to carry the dust into a neighbours property. They face pretty hefty fines if caught and sometimes these penalties are “sheeted” home to the owners of the property.
No other method such as heat guns, routers or grinder/planers are recommended.