GAS NETWORKS UNI 7129-X and UNI 11528

  • The internal system (pipes, valves, fittings, taps, joints, special parts) and the materials used must meet the requirements set forth in Article 3, paragraph 2. The sizing of gaseous fuel supply pipes, accessories, devices, special parts, and any pressure reducers forming part of the internal system must ensure the proper functioning of the utilization devices, in compliance with the pressures established for each device by the respective manufacturer. The leak test must be performed in accordance with current technical standards or equivalents. The measuring unit (device not included in the internal system), where applicable, must be installed in accordance with current technical standards or equivalents. The route between the delivery point and the utilization devices must be as short as possible and, outside and/or inside the buildings, must be constructed in accordance with current technical standards or equivalents. In particular, the following installation methods are permitted within buildings where the cases listed below apply:
  • in special fire-resistant housings, when passing through or through buildings or rooms intended for civilian use or for activities subject to fire prevention inspections and inspections pursuant to Annex 1 of Presidential Decree no. 151 of 1 August 2011;
  • in steel sheathing when passing through rooms not included in the previous point, permanently ventilated hallways, or cavities, provided that the route is accessible for inspection. In the rooms where the appliances are installed, the piping route is permitted to be visible and in any case in accordance with the methods established by current technical standards. Furthermore, in the hallway or – where applicable – in the smoke-proof filter (as defined pursuant to Ministerial Decree 30.11.83), installation in housings or sheathing is not necessary provided that the penetrations through the fire-resistant structures are sealed. When passing through horizontal load-bearing elements, the pipe must be protected by a sheath protruding at least 20 mm from the floor, and the cavity between the pipe and the sheath must be sealed with suitable materials. The use of plaster is prohibited. In the case of above-ground entrance halls and not above basement levels, the installation of pipes under the floor is permitted, protected by a sheath equipped with vents at the ends towards the outside. 10. For installations serving rooms or buildings used for industrial activities, the provisions of the Minister of Economic Development decree of 16 April 2008 apply. 11. Pressure reducers that are not an integral part of the installed user appliances and whose conformity is not included in that of the user appliance itself, must be installed outside the buildings. 12. Any free sockets in the internal system must be closed with threaded caps and are permitted inside the rooms if intended exclusively for the installation of appliances. 13. Outside the appliance installation rooms, a manual shut-off valve with a quick-closing mechanism for 90° rotation and a limit stop in the fully open and fully closed positions must be installed on each gas supply pipe, in a visible and easily accessible position. This valve may also be installed in any access room, filter, or fireproof cavity, provided it is easily accessible from the outside in an emergency. 14. In the case of cavities that are ventilated from above and connected to an open space, sheathing is not required, provided the pipes are metal with welded or brazed pipes. 2.3.3.1 Sheaths 1. 2. 3. 1. 2. The sheaths must be:
  • exposed;
  • made of steel with a minimum thickness of 2 mm and a diameter at least 2 cm larger than that of the gas pipe;
  • equipped with at least one vent to the outside. If one end of the sheath faces inward, it must be sealed internally with non-combustible material. Pipes must not have mechanical joints inside the sheaths. Flame-retardant metal or plastic sheaths are permitted when passing through external walls or attics. 2.3.3.2 Fire-resistant housings The fire-resistant housing must:
  • be gas-tight;
  • be made of Italian class 0 or European class A1 materials;
  • have fire resistance characteristics equal to those required for the walls of the room or compartment being passed through and in any case not less than REI/EI 30. The ducts must not have mechanical joints inside the non-inspectable housings. The housings must be permanently ventilated to the outside with openings at both ends. The ventilation opening at the lowest level must be equipped with a flame arrester and, in the case of gas with a density greater than 0.8, must be located above ground level, at a distance measured horizontally of at least 10 metres from other openings at the same or lower level.

    • Fire safety regulations for residential buildings

    Point 6 of Ministerial Decree no. 246 of 16 May 1987, concerning "Fire safety regulations for residential buildings", states: "The main combustible gas pipes must be external to the building and exposed. Crossing rooms is permitted provided that the pipes are placed in a metal sheath open at both ends, communicating with the outside, and with a diameter at least 2 cm larger than the diameter of the internal pipe." "Main pipes" are defined as pipes serving the building's utilities supplied by the gas system, i.e., sub-columns and risers. The installation of "main pipes" is permitted inside the building in a special housing which: ▪ exclusively serves the gas system; ▪ has gas-tight walls; ▪ is permanently ventilated with openings at both ends; The lowest ventilation opening must be equipped with a fireproof mesh and, in the case of gas with a density greater than 0.8, must be located above ground level, at a distance, measured horizontally, of at least 10 m from other openings at the same or lower level; ▪ It must be equipped, on each floor, with a gas-tight inspection hatch with a fire resistance of at least REI 30. The aforementioned housing may also be used to house meters for users of the various floors of the building. The relevant offices are requested to take the above into account when carrying out fire prevention services. The main conductors are therefore the risers and sub-columns. Currently, these are external to the building and therefore compliant with technical regulations.

    RTV 13 – V.13.4.3 - Safety of technological and service systems

    In linea con il D.M. 246/87 e D.M. 25 gennaio 2019

    Download technical specifications

    SYNTHESIS

    The position of methane gas pipes on building facades is regulated by specific regulations to ensure safety and efficiency.

    Here are some general indications based on Italian legislation (UNI 7129 and related standards):


    1. Routes and positioning

    External routing preference: If possible, pipes should be routed outside the building to reduce the risk of gas leaks inside.

    Distance from openings: They must be installed at least 30 cm from doors, windows, vents and other openings to prevent gas accumulation in the event of a leak.

    Distance from electrical systems: They must be positioned at least 10 cm away from electrical cables and appliances and must not cross electrical ducts without adequate protection.

    Distance from the ground: They must be installed at least 2.2 metres above ground level if they cross pedestrian or passage areas.


    1.1 Positioning on the facade

    • Preference for external routesGas pipes should be routed outside buildings whenever possible to reduce the risk of gas accumulation in the event of a leak.
    • Minimum ground clearance:
    • If installed in pedestrian or transitable areas, they must be placed at least 2.2 meters above the ground to avoid accidental impacts.
    • In case of lower height, they must be protected with special mechanical barriers.
    • Distances from openings and electrical systems:
    • At least 30 cm from windows, air vents, manholes, ventilation grilles and other openings.
    • At least 10 cm from electrical cables and electrical devices to avoid interference and possible fires in case of leakage.
    • Distances from balconies and overhangs:
    • Avoid walking under balconies or canopies without adequate ventilation. If unavoidable, ensure adequate ventilation or protection.


    2. Type of materials

    Steel, copper, or polyethylene: The materials must be certified and corrosion-resistant. If the pipes are copper, they must have a protective sheath where they pass through walls.

    Protection against impacts and atmospheric agents: If installed on the facade, they must be protected against impacts and fixed with suitable brackets.

    • Galvanized steel: Painted or coated to prevent corrosion, with welded or threaded joints.
    • Copper: It must be equipped with a protective sheath if laid outdoors.
    • Polyethylene (PE): Only allowed underground, is not permitted for visible installations on facades.


    3. Brackets and fixings

    Pipes must be securely attached to the facade with brackets spaced according to regulations (generally every 1-2 meters, depending on the material). If they pass through structural joints or areas subject to movement, they must include expansion joints.

    • Brackets and supports:
    • They must be positioned at regular intervals (approximately 1.5 m for steel pipes and 1 m for copper pipes).
    • Weatherproof and corrosion-resistant fasteners.
    • Impact protection:
    • If installed in areas at risk of impact, they must be protected with metal casings or suitable ducts.
    • If they pass near moving structures (e.g. gates), they must be equipped with flexible joints to absorb expansion.


    4. Prohibitions and restrictions

    They must not be installed under balconies or in closed spaces without ventilation.

    Avoid long routes with too many curves to limit load losses.

    🚫 Prohibition of installation in closed, unventilated spaces (e.g. false walls, non-inspectable shafts).
    🚫         Prohibition on crossing high fire risk areas (e.g. garages, flammable material storage areas).
    🚫         Do not install directly into the wall without protective sheath and inspectionability.


    The position of gas pipes on the facades of buildings is regulated by Italian legislation, in particular by UNI 7129:2015 and from UNI 11528:2014 for higher-power systems. Below are the main guidelines for safe and compliant installation.

    DISTANCES FROM COMBUSTIBLE MATERIALS The safety distances of gas pipes from combustible materials are regulated by UNI 7129:2015 and UNI 11528:2014 for larger systems. These standards establish fundamental requirements to prevent fires, ensure safety, and comply with correct separation distances. 1. Minimum distances from combustible materials General minimum distance: Gas pipes must be installed at least 10 cm from combustible materials (wood, plasterboard, plastic, etc.), unless adequately protected. Protection with sheaths or coatings: If the pipe is made of steel or uncoated copper, it must be at least 5 cm away from combustible materials or be insulated with heat-resistant protective sheathing. If the pipe is made of coated copper or painted galvanized steel, it can be installed in contact with combustible materials without specific distances, as long as the surface temperature does not exceed safety limits. Plastic materials or polyethylene (PE) pipes: They cannot be installed exposed inside buildings. If buried or recessed, they must be placed inside protective sheaths. 2. Penetrations of combustible walls and floors Protection with metal sheath: If a gas pipe penetrates a wall or floor made of wood or other combustible material, it must be protected with a metal sheath or other fire-resistant material (e.g., self-extinguishing PVC). Internal distance in the sheath: The sheath must ensure at least 5 mm of free space around the pipe to allow ventilation and prevent overheating. 3. Distance from chimneys and heat sources Minimum distance from chimneys, ovens, or other heat sources: 20 cm if the pipe is made of galvanized steel or copper. 40 cm if the pipe is made of plastic with a protective sheath. If these distances cannot be respected, a thermal insulation barrier must be provided between the pipe and the heat source. 4. Additional protection standards ✅ Brackets and fixings: Pipes must be fixed with fireproof metal brackets if installed on combustible surfaces. ✅ Fireproof paints: If the pipe is in contact with flammable materials, it can be treated with intumescent paints to increase heat resistance. ✅ Ventilated areas: Install pipes in well-ventilated areas to reduce the risk of gas accumulation in the event of a leak.