Equipment and supplies Design and construction 10 Air conditioning 5 Chemical engineering 5 Heating 5 Ventilation 5 Fluid dynamics 4 rhagor ... Maintenance and repair 4 Testing 4 Chemical plants 3 Chemical process control 3 Data processing 3 Heat 3 Heat exchangers 3 Refrigeration and refrigerating machinery 3 Boilers 2 Chemical processes 2 Chemistry 2 Chemistry, Technical 2 Combustion 2 Condensers (Steam) 2 Energy facilities 2 Environmental aspects 2 Environmental engineering 2 Extraction (Chemistry) 2 Materials 2 Natural gas 2 Oil storage tanks 2 Petroleum pipelines 2 Petroleum refineries 2 llai ...