All helmets are tested by the CEN (European Committee for Standardization), chiefly for shock and energy absorption and conical impact. Testing and the attendant certification are required for helmets sold in Europe but not necessarily for those in the United States, although, again, all do conform to the standard. Of note, helmets are mostly designed and tested for top-down impacts, such as being hit on the head by falling rock or ice. Side-impact protection, such as you would receive in a fall, are of secondary importance, if any at all. Still, a helmet will offer some measure of side-impact protection—better than nothing.
Suspension and Shell
Helmets come in two basic styles: the time-tested internal webbing-suspension system, and the newer polystyrene foam liner. Both systems have protective shells, and are constructed to absorb impact, though in different ways. Internal strapping systems stretch, with the shell providing the rigidity to ward off impacts and falling rocks or ice, while polystyrene liners deform or shatter to absorb the force. Anymore, most helmets are of the polystyrene type, which are lighter and sexier looking than plastic-shell models with suspensions. Plastic helmets are more durable, resistant to having crampons, ice screws and cams bash against them inside a pack, and for this reason are often the choice for schools, gyms and guides who need gear that can take abuse.
One new model, the Sirocco by Petzl, is made entirely of a durable, rubbery foam, and is the lightest weight available, if also among the most expensive. Expect to see more of this type of construction in the future.
Webbing-suspension helmets are very adjustable to individual head sizes, and may be one-size-fits-all. Their adjustability facilitates easy layering (taking off and putting on hats or liners) for the cold, or, don’t laugh, snugging the helmet after a close hair cut. Webbing suspension, by their nature, offer good ventilation by creating air pockets between your noggin and the helmet shell, a plus if you are climbing in warm temperatures. Generally, helmets of this type costs less than helmets with polystyrene-foam construction.
Polystyrene-foam construction are designed to be particularly light and comfortable, and as such are especially well-suited to summer or sport cragging. They come in different shell sizes, so size them carefully. You adjust the fit by adding or subtracting internal pad shims, or adjusting the headband. Take care to carefully pack a helmet of this design. Sharp objects such as ice tools, screws, nut tools, can gouge the lining.
Methods abound for fine-tuning the fit. Some helmets use simple dials to tighten or loosen the headband. Others use conventional straps and buckles. Either way, make sure your helmet fits snug—a loose-fitting helmet compromises its protection.
A key helmet option is a clips for headlamps, essential for climbers who tend to pre-dawn starts or long routes. Every helmet in this Gear Guide has a lamp mount. If you are shopping for a helmet not included here, make certain that it accommodates your headlamp.