The RST (Retention Strength Testing) now calls for the helmet sample to be supported on its lower edge. This is intended to eliminate and test failure due to liner compression. This test's criteria are uniformly higher than the certification criteria in order to ensure that, during standards enforcement, measurement uncertainty will not reasonably cause a good helmet to fail.

However, RST testing calls for the same impact velocities as certification and which are also subject to measurement uncertainties. If velocity uncertainty should cause a helmet to fail in RST, the matter will be set tight in a second round of enforcement testing.

When a helmet fails in RST, three more samples are tested to confirm that failure. The same RST criteria apply but these samples are tested at deviation level velocities which are uniformly lower than certification test velocities. If all three samples meet the test requirements, the previous RST failure is thrown out. But if any of the samples fail, it's back to the drawing board for the manufacturer.

Helmet Sizing Concerns
Helmets must meet requirements over their entire range of head sizes. In previous Snell standards, if a helmet met impact requirements on the largest appropriate head form, it would also meet them reliably on smaller test head forms. But, for SA2010, helmets must be tested on the largest and smallest appropriate head forms if there is to be any confidence that helmets will meet requirements reliably throughout their intended size ranges. Snell has a procedure for determining the largest head form a helmet will fit but, unfortunately, it knows of no good way to determine which might be the smallest head form. Instead, SA2010 will require manufacturers to declare the intended size range of each helmet submitted for certification, as you can see outlined in Chart 2.

Head-and-Neck Restraints
One of our favorite topics here at CT is the head-and-neck restraint. As part of the new Snell standards the Foundation has added a standard specifically for HNRs in the form of an addendum. Helmets that meet all the requirements for SA2010 and which also meet the addendum's requirements will be eligible for SAH2010 certification labels indicating FHR (frontal head restraint) capability.

In order for a helmet with provisions for what many call "HANS clips" to be tested and (presumably) certified, it must pass a fairly stringent set of limitations before testing, including all necessary hardware is already fixed in the helmet shell with M6 female threads accessible through holes in the shell for the attachment of helmet tether assemblies. There will be at least four turns of thread securing the tether attachment within the shell fixed hardware. A minimum footing area between the tether attachment and the exterior surface of the helmet shell with minimum intrusion of the hardware into the helmet interior is required. The limitations also require that the inner surface of the helmet's shock liner be no closer than 20 mm to the innermost surface of the shell fixed hardware.

The head-and-neck restraint helmets are then subjected to three separate tests; symmetrical frontal impact tests at two different loads, and an offset test. In order for a helmet to achieve certification, it must pass all three tests. The procedures, which are shown in the photo on the following page and Illustrations 1 and 2, test the strength and durability of the clips, anchors, and tethers.

The Bottom Line
The new SA2010 specs functionally require helmet manufacturers to make more actual sizes of helmets, which results in overall better fitting helmets with a better size-to-weight ratio in many cases. Although the differences in testing criteria make SA2005 and SA2010 incompatible, Snell representatives say that the SA2005-certified helmets still offer a high level of protection. What the 2010 standards offer is a more realistic interpretation of human biological factors in the test methodologies. The bottom line is that there will be more and better head and head-and-neck protection for racers. By the time you read this, all of the major helmet manufacturers will have their SA2010 helmets on the shelves ready to ship to you. With the new season here, now may be the perfect time to upgrade from that old SA2005 helmet.