07 MATHEMATICS. NATURAL SCIENCES 07.100 Microbiology 07.100.20 Microbiology of water 13 ENVIRONMENT. HEALTH PROTECTION. SAFETY 13.060 Water quality 13.060.20 Drinking water 13.060.99 Other standards related to water quality 19 TESTING 19.060 Mechanical testing 19.100 Non-destructive testing 19.120 Particle size analysis. Sieving23 FLUID SYSTEMS AND COMPONENTS FOR GENERAL USE 23.040 Pipeline components and pipelines 23.040.20 Plastics pipes 23.040.40 Metal fittings 23.040.45 Plastics fittings 23.040.99 Other pipeline component 23.060 Valves 23.060.50 Check valves 23.060.99 Other valves 23.100 Fluid power systems 23.100.40 Piping and couplings 71 CHEMICAL TECHNOLOGY 71.040 Analytical chemistry 71.040.01 Analytical chemistry in general 71.040.10 Chemical laboratories. Laboratory equipment 71.040.20 Laboratory ware and related apparatus 71.040.30 Chemical reagents 71.040.40 Chemical analysis 71.040.50 Physicochemical methods of analysis 71.040.99 Other standards related to analytical chemistry 71.060 Inorganic chemicals 71.060.01 Inorganic chemicals in general 71.060.10 Chemical elements 71.060.20 Oxides 71.060.30 Acids 71.060.40 Bases 71.060.50 Salts 71.060.99 Other inorganic chemicals 71.080 Organic chemicals 71.080.01 Organic chemicals in general 71.080.10 Aliphatic hydrocarbons 71.080.15 Aromatic hydrocarbons 71.080.20 Halogenated hydrocarbons 71.080.30 Organic nitrogen compounds 71.080.40 Organic acids 71.080.50 Anhydrides 71.080.60 Alcohols. Ethers 71.080.70 Esters 71.080.80 Aldehydes and ketones 71.080.90 Phenols 71.080.99 Other organic chemicals 71.100 Products of the chemical industry 71.100.80 Chemicals for purification of water 91 CONSTRUCTION MATERIALS AND BUILDING 91.140 Installations in buildings 91.140.60 Water supply systems 91.140.70 Sanitary installations |