Purge & Pressurization – Simple Solutions to Complex Problems
Hazardous locations provide some of the greatest challenges to facility and electrical equipment safety. Fortunately, many protection concepts can be utilized when placing electrical equipment in hazardous locations. Some of the most widely used are Explosion-Proof or Intrinsically Safe concepts which focus on containment or prevention of ignition.
However, one of the easiest to understand and use is Purge and Pressurization (Ex p) – a simple protection concept that excludes any hazardous material from the equipment installation.
Ex p offers many advantages over other protection concepts - since general-purpose electrical equipment and enclosures can be used, it makes system design, assembly, and commissioning simpler. Safety is greatly enhanced, as Ex p is an active protection method – if there is a loss of enclosure pressure an alarm or shutdown will result. This is typically not the case with other protection methods. Certification is generally faster and lower cost than other methods.
How does it work?
With virtually no limitations on the type of equipment that can be protected, Purge & Pressurization is more flexible and cost-effective than a typical Explosion-Proof solution.
Purge: The purge system supplies clean, dry instrument air to the enclosure at a high flow rate for a pre-set time, expelling any potentially flammable atmosphere remaining inside. Enclosure pressure and purge flow are monitored. The electrical equipment inside the enclosure is not energised.
Pressurization: After purge is complete, the system supplies sufficient air to maintain a constant pressure inside the enclosure, compensating for any small leaks, preventing ingress of the outside atmosphere. Enclosure pressure is monitored. The electrical equipment inside the enclosure can be energised.