11
Water intake apparatus; fittings for gas and water apparatus and pipes; water-softening apparatus; desalination plants; filters for drinking water; gas generators (installations); purification installations for sewage; cooling installations; cooling installations for water; feeding apparatus for heating boilers; regulating and safety accessories for water apparatus; clarifying installations; pipes and tubes; forming parts of hot water systems; coils (parts of distilling, heating or cooling installations); safety equipment for water and gas apparatus or for water and gas pipes; water-heating installations; air valves for steam-heating installations; regulating accessories for water or gas apparatus and pipes; safety accessories for water or gas apparatus and pipes; water distribution installations; water-filtering apparatus; water supply installations; pipes (parts of sanitary installations); water conduits installations; water softening apparatus and installations; water purification installations; water-purifying apparatus and machines; flushing apparatus; heat pumps; heat exchangers (not parts of machines)
37
Irrigation devices installation and repair; drilling of wells; construction; pipeline construction and maintenance; pump repair; plumbing; rental of earth-moving machines; underwater construction; underwater repair; heating equipment installation and repair; rental of excavators
42
Geological prospecting; geological surveys; engineering; construction drafting; engineering drawing