21 MECHANICAL SYSTEMS AND COMPONENTS FOR GENERAL USE 21.020 Characteristics and design of machines, apparatus, equipment 21.040 Screw threads 21.040.20 Inch screw threads 21.040.30 Special screw threads 21.060 Fasteners 21.060.01 Fasteners in general 21.060.10 Bolts, screws, studs 21.060.20 Nuts 21.060.30 Washers, locking elements 21.060.40 Rivets 21.060.50 Pins, nails 21.060.60 Rings, bushes, sleeves, collars 21.060.70 Clamps and staples 21.060.99 Other fasteners 21.080 Hinges, eyelets and other articulated joints 21.100 Bearings 21.100.01 Bearings in general 21.100.10 Plain bearings 21.100.20 Rolling bearings 21.120 Shafts and couplings 21.120.01 Shafts and couplings in general 21.120.10 Shafts 21.120.20 Couplings 21.120.30 Keys and keyways, splines 21.120.40 Balancing and balancing machines 21.120.99 Other standards related to shafts and couplings 21.140 Seals, glands 21.160 Springs 21.180 Housings, enclosures, other machine parts 21.200 Gears 21.220 Flexible drives and transmissions 21.220.01 Flexible drives and transmissions in general 21.220.10 Belt drives and their components 21.220.20 Cable or rope drives and their components 21.220.30 Chain drives and their components 21.220.99 Other flexible drives and transmissions 21.240 Rotary-reciprocating mechanisms and their parts 21.260 Lubrication systems27 ENERGY AND HEAT TRANSFER ENGINEERING 27.010 Energy and heat transfer engineering in general91 CONSTRUCTION MATERIALS AND BUILDING 91.010 Construction industry 91.010.01 Construction industry in general 91.010.10 Legal aspects 91.010.20 Contractual aspects 91.010.30 Technical aspects 91.010.99 Other aspects 91.060 Elements of buildings 91.060.01 Elements of buildings in general 91.060.10 Walls. Partitions. Façades 91.060.20 Roofs 91.060.30 Ceilings. Floors. Stairs 91.060.40 Chimneys, shafts, ducts 91.060.50 Doors and windows 91.060.99 Other elements of buildings 91.080 Structures of buildings 91.080.01 Structures of buildings in general 91.080.10 Metal structures 91.080.13 Steel structures 91.080.17 Aluminium structures 91.080.20 Timber structures 91.080.30 Masonry 91.080.40 Concrete structures 91.080.99 Other structures 91.090 External structures 91.100 Construction materials 91.100.01 Construction materials in general 91.100.10 Cement. Gypsum. Lime. Mortar 91.100.15 Mineral materials and products 91.100.23 Ceramic tiles 91.100.25 Terracotta building products 91.100.30 Concrete and concrete products 91.100.40 Products in fibre-reinforced cement 91.100.50 Binders. Sealing materials 91.100.60 Thermal and sound insulating materials 91.100.99 Other construction materials 91.120 Protection of and in buildings 91.120.01 Protection of and in buildings in general 91.120.10 Thermal insulation of buildings 91.120.20 Acoustics in building. Sound insulation 91.120.25 Seismic and vibration protection 91.120.30 Waterproofing 91.120.40 Lightning protection 91.120.99 Other standards related to protection of and in buildings 91.180 Interior finishing 91.190 Building accessories93 CIVIL ENGINEERING 93.020 Earthworks. Excavations. Foundation construction.Underground works |