Reference: Norma NBR 9256 - Installation of galvanized pipes and fittings for cold water installations.

Item 4.3 - The wrapping of the tube with moisture-permeable heterogeneous materials or infiltrations of water, and the intimate contact of the tube with other metal materials to prevent the formation of potential differences in corrosion, shall be avoided.

Item 4.4 - Tubes should not be installed on toilet floors, kitchens, and similar compartments to prevent detergent or other cleaning materials from seeping into the tubing liner.

Item 4.5 - All pipes buried in gardens or applied in humid places must be protected with bituminous paint and / or with polyethylene or polyvinyl plastic tape, or other materials and products that in a similar way ensure the same protection

Item 4.6 - The grounding of any electrical appliance in the galvanized pipes is strictly forbidden, for safety and in order to avoid harmful conduction of its constituent parts.

Reference: NBR 14570 - Internal installations for alternative use of NG and LPG gases - Design and execution

Item 4.3.3 Buried or buried pipelines shall

  • a) Have a minimum distance of 0.30 m of electricity conductors if they are protected by conduits, and 0.50 m in the opposite cases;
  • b) Having a spacing from the other pipes sufficient to be maintained in them;
  • c) Have a distance of at least 2 m of lightning rods and their respective grounding points or according to NBR 5419;
  • d) Be encased in a solid coating, when embedded in a wall.

NBR 14570 - Item 4.4 Pipe Installation - Internal distribution network

Item 4.4.1 - The internal distribution network may be built-in or apparent and shall receive the appropriate treatment for external surface protection (when necessary).

Annex E (informative) Pipe care

E.1 The metallic materials used to conduct the fuel gas specified in this standard may suffer corrosion (the natural tendency of the materials to return to their state found in nature by releasing energy), and for this reason they must be installed properly to minimize this phenomenon.

E.2 To minimize the effects of corrosion, consider whether the piping is:

  • buried in soil or in wet areas of the building: properly cover it with a material that guarantees its integrity such as: asphalt coating, plastic coating, with tapes, epoxy paint, or carry out a cathodic protection system to the network (this process requires the knowledge of a specialist).
  • apparent: the local atmospheric and environmental conditions must be analyzed to define the necessary protection, and even the protection applied in buried pipes or paint can be used. The finish, regardless of the type of corrosion protection used, must comply with 4.5 of this standard

Item 4.5 - Identification: All apparent piping shall be painted in yellow according to Munsell system standard 5Y8 / 12

Reference: NBR 5626 - Installation of cold water.

Item 4.2 Protection against corrosion or degradation.

Item 4.2.1 - Corrosion of metallic materials and degradation of plastic materials are particularly important phenomena to consider from the component selection stage to the use phase of the cold water building. They are complex phenomena to which factors of various natures contribute. Annex D deals with the theme presenting considerations, parameters and correlations that translate the stage of the current knowledge of the subject.

Item 4.2.2 - Cold water building inhalations shall be protected, enforced and used in order to avoid or minimize corrosion or degradation problems. To this end, at least the recommendations in Annex D shall be observed.

Item 5.2.4 - No piping shall be installed buried in contaminated soils. In the absence of care, effective protection measures should be adopted.

Item - No tubing susceptible to deterioration, when in contact with a particular substance, may be installed where such substance may be present, unless measures are taken to avoid contact of such substances with the piping.

NBR 5626 - Item 5.6.3 Piping installed inside walls or floors.

Item - Installing pipes inside walls or floors (covered or recessed tubing) should consider two basic issues: maintenance and movement of pipes in relation to walls or floors. With regard to handling in particular, it is necessary to preserve the physical and functional integrity of the pipes in front of the displacements provided in the walls or floors.

Item 5.6.5 - Buried pipelines - Buried pipelines shall withstand the action of the soliciting forces resulting from traffic loads as well as be protected against corrosion and be installed in such a way as to avoid damaging deformations arising from soil settling. When there is ground level flooring, it is recommended that the buried piping be installed in the duct to ensure accessibility for maintenance.

Item - In soft soils, subject to settling, or in terrains of differentiated characteristics, special cradles must be designed, taking into consideration the requests to which it will be subjected to the piping in function of the efforts applied to the surface of the terrain.

Item - The installation of piping inside structural masonry wall is allowed, provided that it is pipe covered in a specially designed duct. In this case, the design of the building structure should contemplate, as an integral part of this the solution adopted for the cold water building.

Item - In the case of buried pipelines, when the intended conditions are unfavorable, suitable for corrosion, the pipeline should receive paint with bituminous paint or other type of antioxidant protection (see Annex D).

NBR 5626 - Annex D (normative) - Corrosion, aging and degradation of pipes used in cold water facilities.

D.1 generalities - Corrosion, aging and degradation are phenomena that deserve particular attention in view of the consequences they have on cold water facilities. These phenomena are extremely complex due to the amount of factors that influence them to occur. The durability of the materials depends, fundamentally, on the nature of the environment and the conditions to which the installations are exposed, and is therefore difficult to predict.

D2.5 Galvanized pipes In zinc - plated (galvanized) carbon steel pipes, the zinc layer largely avoids the occurrence of corrosion. For the good performance of this material in cold water facilities, the following recommendations should be taken into account:

  • Consideration should be given to the medium in which the pipes are installed and, where necessary, to provide some type of protection against external corrosion of the pipes. In embedded pipes, it is recommended that the piping be installed in such a way as to be in contact with the homogeneous material, preferably alkaline, as for example the material provided by the mortar, provided they have low chloride contents, frequent in the additives of picking and hardening;
  • Buried pipes must be protected so that soils containing aggressive agents do not cause external corrosion of galvanized steel. For protection, the pipes can be placed in concrete shields, painted with bituminous material or undergo other types of protection.

In addition to all the normative requirements explained above it is very important to also consider the following recommendations

If the tube has to be coated or insulated, care must be taken in respect of the products used which, while offering adequate insulation, may be aggressive to the tube;

In the case of the use of mortar as a medium the piping, we refer to the standards DIN 1164 (cement), NBR 6118 (Design and execution of works of reinforced concrete and NBR 7211 (Aggregate for concrete) and taking into consideration the traces of mortar, it is recommended that it has a maximum content of 0.001% of chlorides and PH between 12,5 and 13);

In industry, in laboratories, in regions with marine atmosphere or others that contain a high content of pollutants and aggressive elements the piping, it is not convenient to use the tubes without a suitable environment such as mortars, paints, varnishes etc. and always trying to control the degree of aggressiveness of this environment;

In the surroundings of the pipes, materials with pH around 12.5 and with low levels of chlorides and sulphates should always be used.