6
Common metal, unwrought or semi/wrought; Alloys of common metal; Cast iron, unwrought or semi-wrought; Buildings of metal; Frames of metal for building; Containers of metal for storage and transport; Containers of metal for compressed gas or liquid air; Bottles of metal for compressed gas or liquid air; Closures of metal for containers
7
Separators; Garbage [waste] disposals; Generators; Steam engine boilers; Steam boilers [parts of machines]; Steam condensers [parts of machines]; Heat exchangers [parts of machines]; Turbocompressors; Compressors [machines]; Pumps [parts of machines, engines or motors]; Compressors for refrigerators
9
Fire-extinguishers
11
Purification installation for sewage; Installations for processing wastewater; Steam boilers [other than parts of machines]; Installations for biogas treatment; Refrigerating chambers; Cooling appliances and installations; Regulating accessories for water or gas apparatus and pipes; Heat exchangers [other than parts of machines]; Pressure water tanks; Furnaces for industrial use
37
Building and repairing construction work; Industrial device installation; Construction of buildings, factories and gasworks; Construction of purification installations for sewage and biogas stations; Construction and assemblage of reactors, water towers, gas holders and large-capacity containers; Installation, repair and overhaul of gas installations, pressure installations and gauges; Installation and repair of industrial furnaces; Transformation of vehicles for fuel gas; Vehicle service stations [refueling and maintenance]; Machinery maintenance; Construction and installation of steel buildings and technology installations; Installation, maintenance and repair of computer hardware; Repair of biogas installations and machines
39
Transport and transfer, except boat; Transport and storage of waste; Bottling services [fuel gas filling into pressure bottles and containers]; Fuel gas haulage and distribution; Distribution and transport of natural gas; Transport and storage of pressure containers; Intermediation of pressure bottling services
40
Custom assembling of materials for others; Metal treating; Treating of natural gas, biogas and gas mixtures; Treatment of waste; Treatment and purification of wastewater