Thanks for that info, Dave.
Doing a little Googling, I ran into this (my brain will be mush after I process all of this)
There are many construction types for imact protectors including Knox's plastic honeycomb(single-use) pieces, T-Pro's rubber-based foam pieces, viscoelastic/temperfoam(memory foam) pads, dual-density plastic foams, various hard plastic pieces and sandwiched-plastics, and Rukka's air-filled protectors.
Soft and hard doesn't differentiate performance levels. If you look at the construction of most CE approved armor you will find that the highest performing products are soft foams(Asterne/Astrosorb 8mm). At less than a centimeter thick, they may even seem flimsy. However, these pieces fall in to the "extreme performance" category for CE impact energy absorption. There are only a few "hard-shell" impact protectors that are rated to the basic level and most are not CE approved. Alpinestars, Dainese, and Erbo all sell hard(harder)-shelled protectors that claim meet the CE basic levels.
Some hard armor may protect against penetration or provide slightly better abrasion resistance than other forms, but penetration injuries are rare. A hard object underneath an outer layer may also damage that outer layer in an impact or slide by reducing the surface area and increasing the pressure at contact points. Flexibility of softer components should also equate to greater comfort and better fit.
You may also see the term "GP" armor used t describe a hard-plastic over foam design, but keep in mind that the "GP" label is a marketing term, and does not imply any real value or meaning, or any exact specification that provides a level of performance. If a European company is selling non-CE approved GP-style pieces alongside its CE approved options, then that should be a clue to the real crash-worthiness of those particular pieces, as they would be using that construction to pass the tests if it was superior.
Similar to Snell and DOT standards for helmets, CE standards for motorcyclist's protective clothing establish a unified testing procedure for products sold in Europe as motorcylcist PPE(Personal Protective Equipment). Under the CE directives, all products have to be tested and approved by an independent, government approved test house.
There are CE standards that cover each part of the body and each category of protective qualities associated with motorcyclist clothing. These include abrasion resistance, tear strength, impact protection, and seam strength. There are standards covering motorcyclist's suits, jackets, pants, and impact protectors("armor"), as well as gloves and footwear.
CE testing in Europe is mandatory for impact protectors, however, it is also required for any motorcyclist clothing claiming or marketing protective qualities. In other words, if a company claims their product is built for protective purposes, it must be backed-up with the independent testing proof of the CE standards. For example, manufacturers can market armor as "impact protectors" only if the pieces meet the requirements or simply "padding" if it is not intended to provide a safety advantage.
The CE standards for impact protectors do not specify any type of construction, strictly performance and coverage area.
There are 2 standards that cover motorcylcist impact protectors. One for limb/joint pieces and the another for back protectors. Each provides various levels of performance based on energy absorption/force transmission.
The CE LIMB/JOINT PROTECTOR standard is labeled EN1621-1.
It allows joint/limb armor to transmit no more than 35kN of force.
Ratings are based on performance at an impact energy of 50, 75, or 100 joules creating three levels of performance within this standard.
LEVEL 1, BASIC--50 joules
LEVEL 2, HIGH PERFORMANCE--75 joules
LEVEL 3, EXTREME PERFROMANCE--100 joules
The CE BACK PROTECTOR standard is labeled EN1621-2. The test is performed with a 5kg "kerbstone" dropped from one meter to create the test impact energy of 50 Joules. The standard contains two levels of force transmission performance, using the same impact energy.
passes LEVEL 1 compliance.
passes LEVEL 2 or "high performance" compliance.
The fact that CE approved armor is tested and proven is the most important point. No other forms of so-called "armor" make claims of protection and/or provide credible evidence of performance. If a company is not willing to show performance results, we shouldn't be buying their products when other, actual certified products exist.
Here's some additional sources of info on proper impact protectors and CE testing: