In reply to captain paranoia:
Sure, but this isn't really my point if you read through my comments. A helmet you wear is better than a helmet you don't, and arguably, if the results of the study above are transferrable, the standard might not really be of much use. There's 2 main scenarios to protect one's head from; a falling object, or a knock when falling off.
Everyone I've known to have had a big hit on the head from a falling rock has had a significant and lifelong injury or terminally worse. Hence linking to the post above, the standard of 8kn is largely irrelevant if your neck breaks at as low as 1.7kn. A marginally compliant soft (EPP) helmet and a marginally non-compliant harder (EPS) helmet (the vapor must be between 8kn and 10kn) are both as much as useless in this scenario, in fact most helmets potentially are at forces approaching the UIAA standard. Looking at the link above one might reasonably conclude that all helmets will more or less protect from the smaller chunks of ice and rock to the point one's neck breaks as well as each other, if you have something coming towards you bigger, you're probably doomed anyway and therefore the standard doesn't really make much difference. I'm "comfortable" with that. I'd prefer it if my climbing partner didn't hack bits of ice down on my head, but I know the helmet I have protects me from that, but if a 10kg chunk comes at me from 25m up, then the helmet is probably not going to help.
Personally, I'm most interested in the second scenario, where I fall off and bash my head as the rope catches me or I clatter something on the way down (
https://www.youtube.com/watch?v=RQXgjTcM-tc). I rarely used to use a helmet outside of ice/mountains/gogarth, because frankly most of the helmets were clunky and/or uncomfortable (including the sirocco). As an example I couldn't actually do The Promise with a helmet (petzl elios) on, so took it off for the lead, and have since gotten out the habit using one at all. This scenario is most likely on something like the grit where hopefully 8kn worth of rock won't fall on my head but where there's a good chance I might fall off. The forces generated here are generally lower, and scenarios more difficult to mimc in testing and are very design specific, and any protection here is better than none.
Black Diamond went out to design a helmet that people actually wear, and they've achieved that. I'd prefer to use a sirocco, not because of the marginal difference in strength but because it's cheaper, however it doesn't fit, and therefore I wouldn't wear it as frequently, which for the reasons above is a stronger argument to not buy it for me.