C     Class 1  General undertakings of road works

C1   Class 1  Current sewer works

C2   Class 1  Water distribution and installation of various canalisations

D     Class 4  General undertakings of buildings

D1   Class 4  All building frame works and bringing under roof of buildings

D4   Class 3  Acoustical or thermal insulation, light partitions, falls ceilings and

raised floors, prefabricated or not

D5   Class 3  General woodwerk, roofs and wooden staircases

D8   Class 4  Roof coverings with asphalt based products

D10 Class 3  Tiling

D12 Class 4  Covering other then metal or asphalt

D16 Class 4  Sanitary installations and heating installations, gas installations

or by seperate engins

D22 Class 4  Metal roof coverings and zinc works

E     Class 1  General undertakings of civil works

G    Class 1  General undertaking of earthworks

P1 Class 3 Electrical building installations, comprising installations

of electrical generation sets, fire protection and burgler devices,

teletransmission inside buildings and their surroundings and

installations or devices for mixte telephone

P2 Class 1 Electrical and electro-mechanial installations of artworks or

industrial works and external electrical installations

P3 Class 1 Installation of air lines for electrical transport

S1 Class 1 Telephone and telegraph equipments