Over the last few years there has become a wider industry acceptance for the installation of double blocking gas valves that are all built into one housing. In Europe, these types of units have been widely accepted for many years, and in the late 1990’s they started to appear in more North American installations.
The popularity of these safety shut off valves continues to rise amongst engineers, contractors, and end users alike. Each finding these units to be less cumbersome, easier to pipe, wire, and control. They take up less space on a manifold and some units can include gas pressure switches, proof of closure, proof of opening, pressure taps, and even gas pressure and zero regulators. Being able to package all these components into one housing has been a driving factor in their increased popularity.
These multi functional gas control devices are generally more expensive than buying the components separately. An example is on a pilot line; two solenoid valves and a reducing regulator are required to satisfy most North American Authority Having Jurisdiction. The three parts require more space and take more time to install, however with the double blocking valve combination control, the installer requires less space on the valve train, and less time to complete the installation, thus the cost factor seems to equalize regardless if one decides to use individual components or one multi function component.
Another added benefit is the time saved in sourcing the equipment from one only supplier, as opposed to multiple component from a few sources. Siemens and Dungs have taken the lead on such components, however the Karl Dungs line of components, customer service, and availability seem to out weight all the competition.
