LIBRARY OF CONGRESS CLASSIFICATION OUTLINE 

CLASS T - TECHNOLOGY

(Click each subclass for details) 

Subclass T Technology (General)

Subclass TA Engineering (General). Civil engineering

Subclass TC Hydraulic engineering. Ocean engineering

Subclass TD Environmental technology. Sanitary engineering

Subclass TE Highway engineering. Roads and pavements

Subclass TF Railroad engineering and operation

Subclass TG Bridge engineering

Subclass TH Building construction

Subclass TJ Mechanical engineering and machinery

Subclass TK Electrical engineering. Electronics. Nuclear engineering

Subclass TL Motor vehicles. Aeronautics. Astronautics

Subclass TN Mining engineering. Metallurgy

Subclass TP Chemical technology

Subclass TR Photography

Subclass TS Manufactures

Subclass TT Handicrafts. Arts and crafts

Subclass TX Home economics
Subclass T 

T1-995 Technology (General)

T10.5-11.9 Communication of technical information

T11.95-12.5 Industrial directories

T55-55.3 Industrial safety. Industrial accident prevention

T55.4-60.8 Industrial engineering. Management engineering

T57-57.97 Applied mathematics. Quantitative methods

T57.6-57.97 Operations research. Systems analysis

T58.4 Managerial control systems

T58.5-58.64 Information technology

T58.6-58.62 Management information systems

T58.7-58.8 Production capacity. Manufacturing capacity

T59-59.2 Standardization

T59.5 Automation

T59.7-59.77 Human engineering in industry. Man-machine systems

T60-60.8 Work measurement. Methods engineering

T61-173 Technical education. Technical schools

T173.2-174.5 Technological change

T175-178 Industrial research. Research and development

T201-342 Patents. Trademarks

T351-385 Mechanical drawing. Engineering graphics

T391-995 Exhibitions. Trade shows. World's fairs
Subclass TA 

TA1-2040 Engineering (General). Civil engineering (General)

TA164 Bioengineering

TA165 Engineering instruments, meters, etc. Industrial instrumentation

TA166-167 Human engineering

TA168 Systems engineering

TA170-171 Environmental engineering

TA174 Engineering design

TA177.4-185 Engineering economy

TA190-194 Management of engineering works

TA197-198 Engineering meteorology

TA213-215 Engineering machinery, tools, and implements

TA329-348 Engineering mathematics. Engineering analysis

TA349-359 Mechanics of engineering. Applied mechanics

TA365-367 Acoustics in engineering. Acoustical engineering

TA401-492 Materials of engineering and construction. Mechanics of materials

TA495 Disasters and engineering

TA501-625 Surveying

TA630-695 Structural engineering (General)

TA703-712 Engineering geology. Rock mechanics. Soil mechanics. 

Underground construction 

TA715-787 Earthwork. Foundations 

TA800-820 Tunneling. Tunnels 

TA1001-1280 Transportation engineering 

TA1501-1820 Applied optics. Photonics 

TA2001-2040 Plasma engineering. Applied plasma dynamics 
Subclass TC 

TC1-978 Hydraulic engineering

TC160-181 Technical hydraulics

TC183-201 General preliminary operations. Dredging. Submarine building

TC203-380 Harbors and coast protective works. Coastal engineering. 

Lighthouses 

TC401-506 River, lake, and water-supply engineering (General) 

TC530-537 River protective works. Regulation. Flood control 

TC540-558 Dams. Barrages 

TC601-791 Canals and inland navigation. Waterways 

TC801-978 Irrigation engineering. Reclamation of wasteland. Drainage 

TC1501-1800 Ocean engineering 
Subclass TD 

TD1-1066 Environmental technology. Sanitary engineering

TD159-168 Municipal engineering

TD169-171.8 Environmental protection

TD172-193.5 Environmental pollution

TD194-195 Environmental effects of industries and plants

TD201-500 Water supply for domestic and industrial purposes

TD419-428 Water pollution

TD429.5-480.7 Water purification. Water treatment and conditioning. Saline

water conversion 

TD481-493 Water distribution systems 

TD511-780 Sewage collection and disposal systems. Sewerage 

TD783-812.5 Municipal refuse. Solid wastes 

TD813-870 Street cleaning. Litter and its removal 

TD878-894 Special types of environment 

Including soil pollution, air pollution, noise pollution 

TD895-899 Industrial and factory sanitation 

TD896-899 Industrial and factory wastes 

TD920-934 Rural and farm sanitary engineering 

TD940-949 Low temperature sanitary engineering 

TD1020-1066 Hazardous substances and their disposal 
Subclass TE 

TE1-450 Highway engineering. Roads and pavements

TE175-176.5 Highway design. Interchanges and intersections

TE177-178.8 Roadside development. Landscaping

TE200-205 Materials for roadmaking

TE206-209.5 Location engineering

TE210-228.3 Construction details

Including foundations, maintenance, equipment 

TE250-278.8 Pavements and paved roads 

TE279 Streets 

TE279.5-298 Pedestrian facilities 

TE280-295 Sidewalks. Footpaths. Flagging 

TE298 Curbs. Curbstones 
Subclass TF 

TF1-1620 

TF200-320 

TF340-499 

TF501-668 

TF670-851 

TF840-851 

TF855-1127 

TF1300-1620 

Railroad engineering and operation 

Railway construction 

Railway equipment and supplies 

Railway operation and management 

Local and light railways 

Elevated railways and subways 

Electric railways 

High speed ground transporation 
Subclass TG 

TG1-470 Bridge engineering 
Subclass TH 

TH1-9745 Building construction

TH845-895 Architectural engineering. Structural engineering of buildings

TH900-915 Construction equipment in building

TH1000-1725 Systems of building construction

Including fireproof construction, concrete construction 

TH2025-3000 Details in building design and construction 

Including walls, roofs 

TH3301-3411 Maintenance and repair 

TH4021-4977 Buildings: Construction with reference to use 

Including public buildings, dwellings 

TH5011-5701 Construction by phase of the work (Building trades) 

TH6014-6081 Environmental engineering of buildings. Sanitary engineering of 

buildings 

TH6101-6887 Plumbing and pipefitting 

TH7005-7699 Heating and ventilation. Air conditioning 

TH7700-7975 Illumination. Lighting 

TH8001-8581 Decoration and decorative furnishings 

TH9025-9745 Protection of buildings 

Including protection from dampness, fire, burglary 
Subclass TJ 

TJ1-1570 Mechanical engineering and machinery

TJ163.13-163.25 Power resources

TJ163.26-163.5 Energy conservation

TJ170-179 Mechanics applied to machinery. Dynamics

TJ181-210 Mechanical movements

TJ210.2-211.47 Mechanical devices and figures. Automata. Ingenious mechanisms. 

Robots (General) 

TJ212-225 Control engineering systems. Automatic machinery (General) 

TJ227-240 Machine design and drawing 

TJ241-254.7 Machine construction (General) 

TJ255-265 Heat engines 

TJ266-267.5 Turbines. Turbomachines (General) 

TJ268-740 Steam engineering 

TJ603-695 Locomotives 

TJ751-805 Miscellaneous motors and engines 

Including gas, gasoline, diesel engines 

TJ807-830 Renewable energy sources 

TJ836-927 Hydraulic machinery 

TJ940-940.5 Vacuum technology 

TJ950-1030 Pneumatic machinery 

TJ1040-1119 Machinery exclusive of prime movers 

TJ1125-1345 Machine shops and machine shop practice 

TJ1350-1418 Hoisting and conveying machinery 

TJ1425-1475 Lifting and pressing machinery 

TJ1480-1496 Agricultural machinery. Farm machinery 

TJ1501-1519 Sewing machines 
Subclass TK 

TK1-9971 Electrical engineering. Electronics. Nuclear engineering

TK301-399 Electric meters

TK452-454.4 Electric apparatus and materials. Electric circuits. Electric

networks 

TK1001-1841 Production of electric energy or power. Powerplants. Central 

stations 

TK2000-2891 Dynamoelectric machinery and auxiliaries 

Including generators, motors, transformers 

TK2896-2985 Production of electricity by direct energy conversion 

TK3001-3521 Distribution or transmission of electric power 

TK4001-4102 Applications of electric power 

TK4125-4399 Electric lighting 

TK4601-4661 Electric heating 

TK5101-6720 Telecommunication 

Including telegraphy, telephone, radio, radar, television 

TK7800-8360 Electronics 

TK7885-7895 Computer engineering. Computer hardware 

TK8300-8360 Photoelectronic devices (General) 

TK9001-9401 Nuclear engineering. Atomic power 

TK9900-9971 Electricity for amateurs. Amateur constructors' manuals 
Subclass TL 

TL1-4050 Motor vehicles. Aeronautics. Astronautics

TL1-484 Motor vehicles. Cycles

TL500-777 Aeronautics. Aeronautical engineering

TL780-785.8 Rocket propulsion. Rockets

TL787-4050 Astronautics. Space travel
Subclass TN 

TN1-997 Mining engineering. Metallurgy

TN263-271 Mineral deposits. Metallic ore deposits. Prospecting

TN275-325 Practical mining operations. Safety measures

TN331-347 Mine transportation, haulage and hoisting. Mining machinery

TN400-580 Ore deposits and mining of particular metals

TN600-799 Metallurgy

TN799.5-948 Nonmetallic minerals

TN950-997 Building and ornamental stones
Subclass TP 

TP1-1185 Chemical technology

TP155-156 Chemical engineering

TP200-248 Chemicals: Manufacture, use, etc.

TP248.13-248.65 Biotechnology

TP250-261 Industrial electrochemistry

TP267.5-301 Explosives and pyrotechnics

TP315-360 Fuel

TP368-456 Food processing and manufacture

TP480-498 Low temperature engineering. Cryogenic engineering. Refrigeration

TP500-660 Fermentation industries. Beverages. Alcohol

TP670-699 Oils, fats, and waxes

TP690-692.5 Petroleum refining. Petroleum products

TP700-746 Illuminating industries (Nonelectric)

TP751-762 Gas industry

TP785-869 Clay industries. Ceramics. Glass

TP875-888 Cement industries

TP890-933 Textile bleaching, dyeing, printing, etc.

TP934-945 Paints, pigments, varnishes, etc.

TP1080-1185 Polymers and polymer manufacture
Subclass TR 

TR1-1050 Photography

TR250-265 Cameras

TR287-500 Photographic processing. Darkroom technique

TR504-508 Transparencies. Diapositives

TR510-545 Color photography

TR550-581 Studio and laboratory

TR590-620 Lighting

TR624-835 Applied photography

Including artistic, commercial, medical photography, 

photocopying processes 

TR845-899 Cinematography. Motion pictures 

TR925-1050 Photomechanical processes 
Subclass TS 

TS1-2301 Manufactures

TS155-194 Production management. Operations management

TS195-198.8 Packaging

TS200-770 Metal manufactures. Metalworking

TS780-788 Stonework

TS800-937 Wood technology. Lumber

TS840-915 Wood products. Furniture

TS920-937 Chemical processing of wood

TS940-1047 Leather industries. Tanning

TS1060-1070 Furs

TS1080-1268 Paper manufacture and trade

TS1300-1865 Textile industries

TS1870-1935 Rubber industry

TS1950-1982 Animal products

TS2120-2159 Cereals and grain. Milling industry

TS2220-2283 Tobacco industry

TS2284-2288 Animal feeds and feed mills. Pet food industry
Subclass TT 

TT1-999 Handicrafts. Arts and crafts

TT161-170.7 Manual training. School shops

TT174-176 Articles for children

TT180-200 Woodworking. Furniture making. Upholstering

TT201-203 Lathework. Turning

TT205-267 Metalworking

TT300-382.8 Painting. Wood finishing

TT387-410 Soft home furnishings

TT490-695 Clothing manufacture. Dressmaking. Tailoring

TT697-927 Home arts. Homecrafts

Including sewing, embroidery, decorative crafts 

TT950-979 Hairdressing. Beauty culture. Barbers' work 

TT980-999 Laundry work 
Subclass TX 

TX1-1110 Home economics 

TX301-339 The house 

Including arrangement, care, servants 

TX341-641 Nutrition. Foods and food supply 

TX642-840 Cooking

TX851-885 Dining-room service 

TX901-946.5 Hospitality industry. Hotels, clubs, restaurants, etc. Food service 

TX950-953 Taverns, barrooms, saloons 

TX955-985 Building operation and housekeeping 

TX1100-1105 Mobile home living 

TX1110 Recreational vehicle living