|As we have stated previously, we are going to be taking the ideas developed in this column over the last couple of years and developing them into design practices. This is how it works. We will provide the basic narrative here for one design practice each week. We will keep it open for comments for one month. After that, we will finish it in formal form and offer it for sale at a modest price. Here is where you come in. If you make a substantive contribution to a standard, the organization for which you work will be granted a pro bono license to use that standard with its current issue number for as long as you like. We have had good response so far! Contribute, please.|
This week's: PVC Air Piping (LGM 2013.006.01 when issued)
Properly encased plastic Polyvinyl Chloride (PVC) piping is a quick and economical way of transporting air. However, plastic air piping does not always conform to local building codes and standards. See 'Considerations' below.
To utilize plastic PVC piping as a means of transporting air.
It is important to note that plastic PVC piping was designed for the transmission of liquids, and is inappropriate for the above-ground transport of compressed air and gases EXCEPT where shatter resistant material of sufficient strength to provide protection from external damage and deterioration encases the pipelines. PVC material does not have shatter resistant properties; pipe and fitting failure under stress from compressed gas may result in an explosion hazard.
If used above ground PVC pipe must be specifically designed to carry compressed air, and must have a pressure rating for compressed gas stamped on the outside of the pipe.
OSHA regulations require black pipe, and most OSHA inspectors are familiar with the black pipe requirement. Also ensure that the pipe is installed so compressed air suitability labels are clearly visible - don't use it when piping is concealed behind walls and structures where labeling is not visible.
The design parameters to be considered for above ground applications include: Thermoplastic piping strength at the operating temperature, the pressure, the energetics and specific failure mechanism need to be evaluated. The strength of PVC decreases as the operating temperature increases and allowable working pressures must be decreased at higher temperatures.
So, give us your comments by 13 March 13, please!
Still open for comments Lightweight aggregate concrete (Open until 6 March 13)
Still open for comments Felted Dryer Drives with integral motor pulleys (Open until 27 Feb 13)
Still open for comments Fabric Roofs (Open until 20 Feb 13)
As always, your comments will be appreciated.
Brian Brogdon, Ph.D.
Send us your comments!