The 8 mm thick acrylic lid of VLM top-loading test chests is a compromise between sufficient heat insulation and heat losses inside the test chamber during corrosion tests. The lid allows heat losses so there is a water condensation as required by the ISO 6270-2 respectively the ASTM D2247.
New: VLM offers hoods for additional thermal insulation for 600 L and 1000 L top loading salt spray cabinets. This is a further contribution to efforts to preserve energy, respectively to reduce the emission of carbon dioxide (CO2). There is a window in the front that allows a view into the test chamber.