Emailed to all the editors listed at Progressive Farmer magazine:

RE: March 2009 page 33 "Compressed Air in a Hoist"

Someone really messed up on this one  PVC air lines are a direct violation of OSHA rules, ANSI, ASME, and ASTM standards (see http://www.osha.gov/dts/hib/hib_data/hib19880520.html)  Besides that it is just unsafe and  ... dumb.

For further discussion see AgTalk http://talk.newagtalk.com/forums/thread-view.asp?tid=88338&post... or do an online search for PVC air shatter.

When steel or copper fails it splits.  When PVC fails it may shatter into shrapnel.

Here is a quote from www.woodworkersjournal.com Issue Date: 159, Posted On: 10/10/2006  (the address was too long to paste)
"Please be aware that OSHA does not recognize PVC as an acceptable means to contain high pressure air in a commercial shop. OSHA will shut down a shop the day they walk in if the shop has a PVC distribution system for high pressure air." – Larry Lyons

There are several quotes at http://torque1st.clubfte.com/OSHA_PVC_Pipe.htm  I find this quote from Jack Roach from Colonial Engineering, INc (a manufacturer I believe) explains it well:
The main problem with using PVC pipe and fittings for compressed gas is not that it spontaneously explodes but that PVC is a brittle material that can be broken or shattered with external force unless properly protected. Compressed gasses can be best described as being analogous to a coiled spring. When a PVC pipe or fitting fails when under stress from compressed gas it literally explodes like a bomb, sending shards of plastic flying several feet in all directions. Liquids, on the other hand, being compressed by only 1/10th of 1% contain very little stored energy. When pressurized systems with liquids fail, the energy is dissipated very quickly, thereby creating a much lower potential for hazard.

And there is always Farm Journal, Sept 28, 2005 http://findarticles.com/p/articles/mi_qn6208/is_20050928/ai_n243958...If you use polyvinyl chloride (PVC) plastic pipe to transport compressed air in your farm shop without a shatterproof protective cover, you're risking an explosion, possible injury and even a fine.PVC pipe is designed to transmit liquids, which leak if the pipe breaks. Gases, in contrast, expand and explode. PVC-pipe-compressed- air lines are known to explode into 1" to 2" shards. "It's a real hazard," says Kirk Lloyd, a farm safety consultant who operates Risk Management Resources in Salem, Ore."

Safety is one area magazine writers and editors need to work on.  I called a propane magazine to task a couple years ago because their cover shot of a new type of water heater showed a non-code fuel line installation. Their response was along the lines of "Well, we contracted the photos ..." That is totally irrelevant.  By printing it they are endorsing it.

Farm magazines have the same responsibility. When a magazine publishes an article or a photo it is implying by example everything in the article is safe.  It really does not matter if John Q Cornfarmer did it, if it is unsafe it should be pointed out as being unsafe or not used.

My personal opinion is this matter rates an article all its own.