Installing a Central Vac in a Plenum Environment

Recently a customer emailed us this question:

"If the central vac is being installed in a plenum environment, is there anything special required? Can PVC pipe be used?"

When I saw this I thought, "What the heck is a plenum environment"  so I forwarded the email onto Brad, our resident expert.  Brad was a central vacuum and intercom installer for 25 years before we brought him in to work with our online customers.  Brad is standing by ready to answer any questions you might have about central vacs, intercoms, and the installation of both.  Our toll free number is 1-800-221-8227.  Here is Brad's answer about a plenum environment:

Good Morning Judy,

A plenum environment is one that is used to transfer air as in return and feed of  HVAC systems.  You should check with local codes to see if PVC is allowed.We have in the past used steel andin rare occasions 2" copper tubing for such applications.Also you will be required to use plenum rated wire.  I believe all this is required to minimize smoke in case of fire.