Posted By Jane Blunt Dear Gary You are not giving enough information. EN141 is the standard for respiratory protective devices - gas filters and combined filters. Whether the filter you have on the shelf is right for the application you have in mind will be indicated by a further code number which should be on the device. A stands for certain organic gases and vapours with boiling point greater than 65 degrees C, as specified by the manufacturer. B stands for certain inorganic gases and vapours as specified by the mnaufacturer. E stands for acidic gases such as sulphur dioxide, as specified by the manufacturer. K is for ammonia and ammonia derivatives, as specified by the manufacturer. P is for particulates whichmay include solids and liquids. and then there are certain special codes. Therefore you need to look at the 'small print' and probably refer back to the manufacturer with your particular application. By the way 'fume' is technically particulate fume from welding. The 'fumes' from acids are different - probably better referred to as acid gases or acid vapours. The standards 12941 and 12942 refer to various types of power assisted respirators. However the important thing is the filter. Jane