Interplast is one of the few companies in Europe with vertically integrated production and the only company in Greece that manufactures all the components of the system while offering a guarantee on the entire heating-plumbing installation. The company's subsidiary ELVIOM S.A. manufactures brass fittings for the Como-pex system.

ELVIOM is a company with 33 years of experience in the production of brass fittings, which are manufactured in compliance with European standards 12164, 12165, 12167 and 12168. The threading on the fittings is constructed according to ISO 228, a standard specifying length and thickness.

The brass fittings comply with German standard DIN 50930/6 which specifies the brass constituents for suitability to drinking water. ELVIOM is certified to ISO 9001 by TUV Germany and its products are distributed to the market having passed the following tests.

• Visual Check of fittings by means of a special projector, where the thickness of the walls and threading is checked.
• Raw materials and final product are checked by a latest generation durometer.
• Pressure tests are carried out at the three company laboratories at pressures up to 6atm.
• The raw materials used by the company have undergone thermal processing (annealing). The fittings with female threading are subjected to thermal processing for a second time, remaining in the stove after production for 1 hour at 350°C. Thus processing stresses are eliminated and durability of the products is increased.
• Strength test by means of a special torque wrench to check torque.
• ELVIOM products are regularly tested in terms of alloy structure (metallography), chemical composition (spectrograph) and the mercury nitrate test for remaining stresses.
• Throughout production the threads, holes and dimensions are checked by means of special controllers. This is particularly important for certain fittings that cannot easily be measured by means of a thickness gauge or strap gauge.