This message is from: "coy...@acrec.com" <coy...@acrec.com>
You are comparing apples and oranges. The issue of polystyrene degrading in a landfill is not related to a helmet keeping its full impact-cushioning properties after years of normal handling and use.
A helmet is designed to be a sacrificial safety item. It has to be fragile enough to crush and deform correctly under the types of impacts for which it was designed.
Even during normal use and handling, a helmet will gets slightly flexed and bumped. Over time, the polystyrene layer can become slightly compressed and even get tiny surface fractures. Also polystyrene gets more brittle with exposure to air pollutants and UV light.
It isn't just the polystyrene layer that is of concern -- the outer shell and the inner harness are also important. The outer shell spreads the force of an impact over more area -- very important for the polystyrene to function correctly to dissipate energy. The inner harness keeps the helmet correctly in place during an impact. With normal use and handling and exposure to sunlight and air, these elements will wear and can become less effective.
These changes resulting from normal use and time might be small, maybe not even visible to the naked eye, but they can gradually reduce the helmet's effectiveness. You need to be reasonably certain that the helmet you are wearing will work the way it is supposed to work upon impact, hence the recommendation to replace a helmet after "X" years of use.
It hasn't come up in this discussion, but I'll also add that motorcycle helmets or bicycle helmets are not substitutes for horse riding helmets. Each helmet is designed for particular types of impacts, including the direction of force and the total force, that are the most common for a particular activity. --DeeAnna
Corinne Logan wrote:
...my helmets all have styrofoam in them ... that stuff never breaks down in our landfills....
Important FjordHorse List Links: Subscription Management: http://tinyurl.com/5msa7e FH-L Archives: http://tinyurl.com/rcepw Classified Ads: http://tinyurl.com/5b5g2f
