If you plan on installing an enclosure in a hazardous area, it is always paramount to install a ‘purge system’ that will withstand harsh surroundings and meet safety or regulatory compliance.
Purge systems are available in many different sizes and configurations, so it is wise to do the proper research and talk to a company or installer who has experience with this type of system. A poorly planned or poorly executed purge system can end up causing a disaster or explosion. But, first comes first, what is enclosure purging and how can it be used to protect computers and other essential peripherals?
How to find the best purge system for the application:
What is purging?
Purging is the process of supplying enclosures with compressed air or inert gas at the proper flow and pressure, in order to reduce the hazardous gas inside of the enclosure to a safe or more moderate level. Pressurization is the process of bringing compressed air within an enclosure to a pressure where there is no ingress of hazardous gases or combustible dust. Both purging and pressurization are required in a Class I or gas atmosphere. However, only pressurization is required in a Class II area or dust atmosphere.
What is used to purge/pressurize?The most common and practical method is compressed ‘instrument quality’ air that contains no more than small trace amounts of combustible vapor. Inert gases, such as nitrogen or argon are acceptable, but are usually expensive and quite impractical. It is vital to create a positive pressure inside of the purged enclosure.
What kind of computer enclosures can be purged?
A computer enclosure with a rating of NEMA 4 or 4X is suitable for a hazardous area. Enclosures that feature heavy-duty gasket and multiple door fasteners are ideal. It is also preferable to choose an enclosure that features an external keyboard tray vs. integrated keyboard drawers. Industrial keyboards or pointing devices (often integrated inside of a stainless steel or polycarbonate case) can then be purchased to accompany the enclosed computer or other peripherals.
How is equipment accessed in a purged computer enclosure?
Equipment mounted in a protected enclosure can be accessed if the area is known to be non-hazardous or if all power to the protected equipment has been de-energized. Internal equipment and electronics should be treated as if located in an explosion proof enclosure. Equipment mounted through the surface of a protected enclosure may be required via a sealed access door, if the equipment is not suitable for exposure to the surrounding atmosphere.
Purge systems are essential and ideal for any industrial setting that may be hazardous. It is best if the purge system is fully automated, so that the purged unit will shut down if the positive pressure is lost inside of the enclosure. However, manual purges also exist, which will alert a user that the purge has been lost and action needs to take place immediately.
Seek out an expert that can help you design the best purge system for your vital equipment.
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