OG 1 Civil and industrial buildings
This involves the construction, maintenance, or renovation of specific building projects necessary to support any human activity, whether direct or indirect. These projects include all required structures, electromechanical, electrical, telephone, and electronic systems, as well as all types of finishes and any related, complementary, or accessory works.
OG 2 Restoration and maintenance of protected immovable cultural heritage
This involves a coordinated set of specialized procedures necessary to recover, preserve, strengthen, transform, restore, renovate, and maintain historic properties that are protected under cultural and environmental heritage regulations. It also includes the installation of electromechanical, electrical, telephone, and electronic systems, as well as all types of finishes and any related, complementary, or accessory works within these properties.
OG 3 Roads, highways, bridges, viaducts, railways, tramways, subways, funicolars, airport runways, and related complementary works
This involves the construction, maintenance, or renovation of networked infrastructure necessary to support mobility by road, rail, and air, regardless of their level of importance. This includes all related, complementary, or accessory works, even on specific points, as well as the associated railway equipment and all required automatic, electromechanical, electrical, telephone, electronic, and electric traction systems needed to ensure a high standard of service for users in terms of usability, information, safety, and assistance.
OG 4 Underground works of art
This involves the construction, maintenance, or renovation of underground structures using specialized technical means, necessary to facilitate mobility by road and rail, regardless of their level of importance. This includes all related, complementary, or accessory works, whether specific or networked, such as access roads of any importance, at-grade or elevated interchanges, surface parking areas, slope reinforcement works, and all required electromechanical, electrical, telephone, and electronic systems, as well as railway equipment necessary to provide a high standard of service for users in terms of usability, information, safety, and assistance.
OG 5 Dams
This involves the construction, maintenance, or renovation of specific projects necessary for water collection for any purpose, located on watercourses and inland basins. These projects include all the necessary electromechanical, mechanical, electrical, telephone, and electronic systems to ensure their efficiency and effectiveness, as well as the networked works or services that support them.
OG 6 Aqueducts, gas pipelines, oil pipelines, irrigation and drainage works
This involves the construction, maintenance, or renovation of networked infrastructure necessary for implementing the „integrated water service,“ or for transporting gaseous or liquid fluids to points of use. These projects are to be complete with all related, complementary, or accessory works, including specific interventions, and all required electromechanical, mechanical, electrical, telephone, and electronic systems to ensure a high standard of service for users in terms of usability, operation, information, safety, and assistance for normal functioning.
OG 7 Maritime works and dredging
This involves the construction, maintenance, or renovation of specific projects in both freshwater and saltwater environments, serving as terminals for water-based mobility or as protective structures for land defense against these waters. These projects include all related, complementary, or accessory works, whether specific or networked, and all necessary electromechanical, electrical, telephone, and electronic systems to ensure a high standard of service for users in terms of usability, operation, information, safety, and assistance.
OG 8 River works, defenses, hydraulic systems, and land reclamation
This involves the construction, maintenance, or renovation of both specific and networked projects necessary for the management of natural or artificial watercourses, as well as for the protection of land from these watercourses. These projects are to be complete with all related, complementary, or accessory works, as well as all necessary electromechanical, electrical, telephone, and electronic systems.
OG 9 Electricity generation plants
This involves the construction, maintenance, or renovation of specific projects necessary for the production of electricity. These projects include all associated masonry works, complementary or accessory components, whether specific or networked, as well as all required electromechanical, electrical, telephone, and electronic systems needed for operation, information, safety, and support.
OG 10 High/medium voltage transformation and distribution system, alternating and direct current distribution systems, and public lighting
This involves the construction, maintenance, or renovation of networked infrastructure necessary for high and medium voltage distribution and for the transformation and low voltage distribution of electricity to the final user. This includes all related masonry works, complementary or accessory components, whether specific or networked, as well as the construction, maintenance, and renovation of public lighting systems to be installed outside of buildings.
OG 11 Technological systems
This refers, within the limits specified in Article 79, paragraph 16, to the supply, installation, management, and maintenance of a coordinated and functionally interconnected set of technological systems that cannot be executed separately, falling under the specialized works categories identified by the acronyms OS 3, OS 28, and OS 30.
OG 12 Remediation works and environmental protection systems
This involves the execution of specific or networked works necessary for environmental remediation and protection.
OG 13 Natural engineering works
This includes the construction, maintenance, or renovation of specific and widespread works or projects necessary for land protection and the restoration of compatibility between „sustainable development“ and the ecosystem, including all works and projects necessary for botanical and zoological activities.