Methane gas Pipe legislation

Methane gas pipes are fundamental components within the systems and, for this reason, the regulation that concerns them is essential to avoid malfunctions or problems of various kinds.
The main legislation dealing with this issue is UNI-CIG 7140, the latest version of which dates back to March 2013. This standard contains all the specifications regarding the materials, the production process and the test methods to be used for testing non-metallic flexible pipes used for installations inside domestic (and civil) systems and characterized by a rated thermal power of less than 35 kW.

A peculiar aspect of this standard is the subdivision of the pipes on the basis of the maximum nominal pressure. In fact, A1 and A2 type pipes, which are generally the categories of pipes that are supplied in the form of rolls, belong to the first class and are characterized by a maximum pressure of 0.2 bar. On the contrary, type B and C pipes, or pipes better known as "couplings", belong to the second class because they are characterized by a maximum pressure with values of two orders of magnitude higher than class one (about 20 bar).

Both classes are characterized by pipes that have a layered structure starting from a synthetic rubber substrate and subsequently articulating in a different way. In particular, the greatest difference that can be found is given by the central reinforcement layer:
The pipes of class I are characterized by a reinforcing layer braided textile material which guarantees both resistance and elasticity;
Class II pipes are characterized by a layer of oxidizable or stainless steel: in particular, the use of stainless steel, in addition to instilling the classic resistance deriving from steel, also allows greater resistance to corrosion, facilitating the work of the outer sheath.

An important aspect, for the purposes of identification and maintenance of methane gas pipes, is the marking, which is a code that uniquely identifies the type of product and which must be reported on the same. Both classes have a marking with the name of the manufacturer, the reference standard followed (in this case the UNI-CIG 7140), the class, the type of pipe and the nominal diameter. The real difference is given by the date of manufacture / replacement: class I has a date by which to replace the component, while class II indicates the date of manufacture.
Compliance with this legislation, or with a corresponding legislation, is essential to create and install qualitatively correct pipes for methane gas and to minimize the risks, improving the safety of the persons who are in contact with them.
 

Methane gas pipes, as previously seen, play a fundamental role in gas systems and must guarantee characteristics and properties that comply with the values indicated in the legislation.
In particular, the tests of interest for this category of components are:
- Visual inspection of the internal surface: carried out by trained and experienced staff, it is a visual investigation aimed at detecting surface defects or problems;
- Extraction test: the pipe must guarantee a minimum value of extraction to be declared compliant. In addition, the pull-out pressure is also evaluated;
- Tensile strength test: most widespread mechanical test aimed at determining the stress, known as breaking, which leads to component failure;
- Crushing resistance test: also in this case a minimum value is required;
- Bending test: aimed at evaluating the ovality of the pipe in the presence of a bend or curve;
- Burst test: it is necessary to find a minimum pressure value higher than that indicated in the standard;
- Hydrogen permeability test and the action of liquefied petroleum gases: necessary to evaluate the resistance to any contamination in operation which can create even significant problems.
Respect for these values is a necessary condition for compliance with the methane gas pipe legislation.

In the previous paragraphs, the subdivision of the standard and all the aspects concerning it has been accurately illustrated, from the division into classes up to the mechanical tests necessary to satisfy the standard, passing through the different markings that can be found on the hoses.
It is essential to emphasize that the absence of just one of these characteristics compromises compliance with the standard and this can be a problem of considerable importance both for the marketing of the products and for their intrinsic quality. For this it is necessary to have an efficient quality management department that checks (according to its own methods) that components are made that precisely comply with all the specifications to obtain the UNI CIG 7140 marking.
Furthermore, there are requirements that must also be followed by the installer so that the hose does not get damaged or deteriorate prematurely.
- Avoid positioning it in such a way as to subject it to tears, twists, bumps, bends;
- Avoid letting it heat above 50 ° C;
- Avoid contact with blades, sharp edges or other protrusions;
- They must not connect two rooms of the same structure by passing through walls.

Compliance with these precautions is as essential as the upstream production process to avoid compromising use and causing damage to nearby structures and persons.
 

I contenuti di questo sito non hanno carattere di periodicità e non rappresentano 'prodotto editoriale'.