Quality is our main goal

Without VAG, water would not be supplied and distributed the way it is today. Wherever water is treated, moved, stored and distributed, VAG's gate valves and butterfly valves, plunger valves and hollow-jet discharge valves, control valves and hydrants play an important role.

There is barely a water, pump or wastewater treatment plant that does not use a VAG valve. Durability and decades of operational reliability matter. Repairing or replacing valves that often weigh several tons, such as those used in dams, is very costly. The supply and distribution of water and the treatment of wastewater are very demanding operations. Valves must be able to withstand high water pressures and extreme temperature and weather conditions. Whether they are used in a desert or a tropical climate, the material must suit the environment. We know from our customers that our valves work reliably for up to fifty years. In fact, some of our valves have been working for more than one hundred years!

While mainly laminar cast iron (GG), or in the case of greater pressure ratings, generally steel and cast steel were previously used, the range of applications of cast iron also changed with the development of GGG materials, so that nowadays in Germany and Europe, "ductile cast iron GGG“, which has similar tough properties to cast steel, is now also being used for higher pressure ratings. This is not only happening in water engineering; it is also happening for extremely demanding applications in the chemical industry and power plant construction. Valves made of ductile cast steel GGG-40.3 (EN-GJS-400-18) are also available for use in lower temperatures.

Certified quality

Company certificates

Product certificates

Coating tests

Coating thickness

Magnetic inductive test to determine the thickness of coatings or corrosion-inhibiting coating agents.
In the picture: Test according to GSK guidelines (Quality Association for the Heavy Duty Corrosion Protection of Powder Coated Valves and Fittings) minimum coat thickness > 250 µm.

Adhesion testing

The pull-off test (DIN EN ISO 4624) is used to test how well the coating is bonded to the raw material. Minimum adhesion > 12 N/mm2.

Impact testing

A pendulum that falls through a fixed distance is used for impact testing. The pendulum hits the coated surface with an energy of 5 Nm. The coating may neither crack nor peel.

Porosity testing

The coating is checked for freeness from porosity using a high-voltage test device at a defined test voltage. The test is performed using a rubber electrode.

Infiltration testing

The cathodic infiltration test is a corrosion test according to GSK guidelines and DIN 30677 that is carried out over a test period of 30 days at 23 °C. A defect is created on the coated surface of the test specimen, which is subjected to cathodic polarisation in a sodium chloride solution for the entire test period.

Pressure, leak and function testing

Pressure, leak and function testing

These pictures show the tests our valves are submitted to and the test benches used. Whether tested with water or air, all of our valves are submitted to pressure, leak and function tests.

Test bench gate valve

Test bench butterfly valves up to DN 600

Test bench butterfly valves bigger DN 600

AWWA Proof-of-design Test

This proof-of-design test is a durability test according to AWWA C 504-87 with 1,000 load alternations against one-sided pressure. (AWWA = American Water Works Association).


VAG Water Systems (Taicang) Co.,Ltd.
No. 15 East Guangzhou Road
Taicang 215400 Jiangsu Province,
People’s Republic of China
+86 (512) 5357 5357 +86 (512) 5357 1825 Write e-mail