Interplast manufactures a range of fittings made of Random polypropylene (type 3) in accordance with DIN 16962. The Aqua-plus fittings are available in cross-section ranging from 20mm to 315mm and have been designed to PN 25 Pressure Series specifications, while ordinary polypropylene fittings are manufactured to PN 20 Pressure Series. The fittings are certified by SKZ.

“PN 20” and “PN 25” relate to two fundamental parameters:

Pressure power and consequent lifespan In terms of pressure testing PN 25 means that during the one-hour test the test samples are subjected to 80 atm. pressure at 20°C. For the PN 20 series the same test is performed at 64 atm. pressure.

Another major reason the company has chosen to design and manufacture PN 25 fittings is the fact that the greater wall thickness of PN 25 fittings enables the design of improved internal geometry in fittings, thus reducing hydraulic loss and substantially improving system flow. For example, the local resistance factor [æ] of the 90° angle for ordinary PN 20 fittings is 1.2, while for PN 25 fittings it is 0.9, i.e. 25% lower.