Eurotubi Pressfitting – FAQ

Eurotubi Pressfitting - FAQ

Pressfitting system means the permanent joining of pipes and fittings through a mechanical pressing operation. A pressfitting system comprises the pipes, the fittings, the o-ring seals and, in the assembly phase, the pressing tools used to produce the joints.

A Pressfitting system is considered approved when it has successfully passed the tests carried out by a Product Certifying Body for a certain application. Eurotubi Pressfitting System has obtained the most important European certifications.
The system is deemed reliable when the requirements of this technical guide are respected, and in particular:

  • the operating conditions set in the accreditation;
  • the general use techniques;
  • the installation instructions.

Eurotubi Pressfitting System can be used for different applications, depending on the material:

  • stainless steel is mainly used for systems for the distribution of drinking water and gas;
  • carbon steel is mainly used for closed circuit hot water heating systems;
  • cupronickel is mainly used in the naval sector for carrying salt water.

The growing diffusion of this joining system has led the Eurotubi Pressfitting System to be used in a much wider range of industrial applications, as mentioned in Technical Guide sections 5, 6 and 7.

The design and installation of the system must respect local regulations, the guidelines developed by industry-best-practice and the requirements stated in this Guide. In Europe many regulations adopted by a country (Germany for example) are recognised as valid and sufficient also in other countries. In any case it is the task of the designer and/or the installer to ensure that the indications contained in Technical Guide are compatible with local legislation.

It is a good rule not to bend pipes, choosing the right fittings for the variable route of the path. However, if necessary, bends can be made, provided that the rule that sets the minimum bending radius at 3.5 times the diameter of the pipe is respected; for stainless steel, this condition only applies if the material is annealed.

There are currently no direct duration tests for seals but only indirect tests. The seals mounted in the Eurotubi joints have successfully passed the most stringent laboratory tests provided for by applicable regulations, intentionally exaggerated to obtain maximum safety.

Absolutely not, this action voids any guarantee, certification and accreditation for the entire system.

The definition “closed circuit” refers to a system characterised by the total absence of air. All the systems that do not belong to this type must be considered as “open circuits”.

Wet sprinkler systems are more common and reliable. The saying “wet” indicates that the pipes are filled with water under pressure. When a sprinkler is exposed to a temperature higher than the intervention temperature for a long enough time, the thermosensitive element breaks and lets the water flow immediately from the nozzles onto the area in flames.

The saying “dry” indicates that the pipes are filled with air under pressure rather than with water. Dry sprinkler systems are installed in spaces where the temperature may be so low that it freezes the water of the wet system, making it unusable. Dry systems are often used in buildings without heating. A special control valve called “dry valve” is positioned in a heated area to prevent the entry of water until a fire causes the activation of the sprinklers. When the nozzles open, air comes out and the pressure in the pipes decreases and causes the dry valve to open. It is only at that time that water enters the pipes and is dispensed through the open sprinklers.

Carbon pipes that are zinc coated both internally and externally supplied by Eurotubi are certified VdS and used in sprinkler fire fighting systems as they are explicitly requested by Guideline VdS – CEA 4001. The use of these pipes for other applications requires careful assessment also based on legal provisions, which vary from country to country.

Carbon connecting pipes that are zinc coated only externally are used for all the other applications. Eurotubi provides pipes that are both galvanically and hot zinc coated externally. The choice depends on the characteristics of resistance to corrosion required by the system (higher for pipes that are hot zinc coated).

Eurotubi Pressfitting systems may have anti freeze products inside them (ethylene glycol), provided these are of good quality. Due to the presence on the market of a large quantity of poor quality anti freeze products, you are responsible to check the characteristics of the products before using them in order to avoid possible serious damage.

These anti freeze products may reach a maximum concentration of 50%. It is not possible to use them with carbon steel pipes that are zinc coated internally (as in sprinkler fire fighting systems), because they cause the zinc to dissolve, with the consequent possible clogging of the installation. On the other hand, carbon steel pipes that are zinc coated only externally may use glycols inside of them.

The fact that carbon steel joints are zinc coated internally is not a problem as their percentage weight in a system is negligible.

For special applications it is indispensable to contact the Eurotubi Technical Department.

In so-called “mixed” installations, stainless steel and carbon steel can be used in contact with other non-ferrous metals without any problem. Direct contact between them, on the other hand, must be avoided to avoid bimetallic corrosion. This topic is described in detail Technical Guide points 10.1 and 10.3.

Stainless steel has an excellent resistance to corrosion, thanks to the high performance of the material. Local perforating corrosion may only occur in extremely aggressive environments that are absolutely outside the norm. This topic is described in detail in Technical Guide point 10.1.

Compared with systems for drinking water, there are no additional requirements to be respected. However, in extreme cases such as the presence of large concentrations of chlorine, salt, marine environments or high temperatures, normal stainless steel decay phenomena may occur. This consideration is valid in general terms and is not linked to the type of pressfitting proposed.

Yes, the extent of this phenomenon depends on the depth and width of the incision as well as on the material that caused it. The worst case lies in a deposit of ferrous material on the incision.

It is necessary to carry out a visual control test of the system and the seal test, as shown in Technical Guide at point 11.1 or according to the regulations in force locally, if more restrictive.

For solar systems we recommend using the stainless steel pressfitting system due to its high resistance to corrosion and the higher quality of the material.

The use of the carbon steel pressfitting system is not excluded but is subject to a perfect thermal insulation to avoid the risk of corrosion and can only apply to a closed circuit system, without the presence of air or steam. Carbon steel connecting pipes must not be zinc coated internally.

As regards o-rings, two solutions may be considered:

  • black o-ring in EPDM, resistant to a maximum continuous temperature of 120°C and even higher for shorter periods; it tolerates steam.
  • green o-ring in FPM, resistant to a maximum continuous temperature of 180°C; it does not tolerate steam.

Both seals are compatible with classic anti-freeze and anti-boiling products

Compressed air systems include a wide range of applications. As a general tip, choose materials based on an in-depth analysis of the requirements needed for the type of installation.

Compressed air systems usually have oil; therefore it is advisable, depending on the purity requirements, to have a dryer or oil separator available. If the amount of residual oil is high ( ≥ 5 mg/m3), we advise replacing the black EPDM o-ring with the red FPM o-ring (better known as Viton), which has a good resistance to oil and mineral grease, oil and synthetic grease and to gas oil.

For these systems, both the stainless steel and the carbon steel Eurotubi Pressfitting System can be used. In any case it is worthwhile to remember that the operating temperature and pressure are two fundamental elements to know when choosing the type of material. The maximum operating pressure is 16 bar.

In carbon steel systems, the presence of moisture may generate corrosion. Installing a dryer is essential.

Finally it is necessary to wet the o-rings with water before assembling the joints.

None, it is only the same initials in the English and German languages.

A system made with Eurotubi pressfittings, with approved connecting pipes, with the correct pressing tools and by closely following the instructions in the Technical Guide is bound to last at least 20 years. However, this indication does not constitute a legal guarantee.

Our company and our products strictly follow the legal provisions concerning the guarantees provided by the seller.

The two profiles are different in shape but in terms of performance there is no difference: they are identical. Both of them must meet the same operating standards, and the same rules and regulations. They must resist the same pressures and temperatures. The same pressing equipment is used. It’s the pressing terminals that change. There are terminals exclusively for the “M” profile, and others only for the “V” profile. The system standards are the same for both profiles. Historically, the first to emerge was the M, then the V was invented.

The choice between V and M profile is at the installer’s discretion and can suit habits and pressing tool availability.
However, as it stands the M profile range by Eurotubi boasts a higher number of certifications than the recent V profile, for which some are pending or scheduled.

To learn more about the topic: Pressfittings: “M” or “V” profile?