For the applications pictured above these types of shrapnel guards could be effective in providing an added layer of safety (though I don't think that the breaking of asphalt would ever generate shrapnel). I don't see how they would work for my application though. I break bedrock and the angles required often would make the chains drift out of position and render them ineffective. There are a couple reasons that I don't like the carpet/mudflap option either. First is that my tool ("point" or "gad"...the part that sticks out and actually contacts the material to be broken) is about 5' long and about 3' sticks out below the housing. That would require a pretty big piece of carpet. Second is the fact that one must use precision to place the tool to the rock. Most of the time this requires that one be able to clearly see what he is doing and the carpet (and to a lesser degree) even the chains create visual obstructions. Fortunately we don't usually have ground personnel near the work, nor do we have to worry about cars, etc. (as in the pictures above). If we are close to buildings, etc. we would use something like plywood. This could even be employed in situations like those portrayed above. What we do have to worry about is the windows of the carrier and those can get expensive now that all the MFRs like to put curved glass on the cabs. For this I have employed plexi-glass window guards that can be easily removed when not hammering. In my experience, most materials that we commonly break do not tend to generate much shrapnel. Experience with the breaker, choosing the correct tool for the material, and the angles of attack that the operator employs also can reduce shrapnel. Some materials will, however be prone to producing shrapnel.
So far, the manufacturers I contacted don't make covers for breaker chisels like the ones shown above. But let's try and spread word about this feature for all breakers..