Within the food industry, the marine and on/offshore industry, in agriculture and horticulture and in swimming pools, specific requirements are frequently stipulated. Customised air treatment units offer a solution. The design of these units centres around hygiene, robustness and cleanability. For instance, we develop customised air treatment units (NKD) for the shipping sector, where the damp environment is a central consideration in the design. One solution, for example, is to construct the air treatment unit entirely from stainless steel.