Bicycle Helmet Safety Institute
The Helmet Update
Vol. 7, No. 2 - July 12, 1989
ANSI Committee Meets to Revise Standard
The ANSI Z90 Committee met in New York in June to mark up a draft of the new ANSI standard for bicycle helmets, due in final form sometime next year.
The biggest changes will be an increase in the flat anvil drop height from 1.0 to 1.5 meters and testing for strap strength after the impact tests. ANSI helmets will have to handle more impact energy without failing, a substantial but not extreme change from the current 1 meter drop requirement. (The Snell standard has a 2 meter flat anvil drop.) The committee left the drop on the hemispheric anvil at 1.0 meter to emphasize the flat anvil test, since most riders hit a flat surface.
Other less fundamental changes: inward-facing sharp edges inside the shell are prohibited, optional devices shall not cause injury, monorail test rigs are permissible, date and model markings inside helmets must be uncoded and visible, and test reports must be retained by the manufacturer.
Needed changes the committee did not make include addition of a retention test (a "roll-off" test as opposed to a simple strap strength test), a test for overloads on any particular point on the head, a specification for ventilation, one for sliding resistance of the shell, for conspicuity of the outer covering and perhaps for maximum weight. A subcommittee chaired by Jim Newman of Biokinetics and including BHSI is to work on the retention question, but without some laboratory test results the committee could not include retention tests and may not be able to do so for years. There is a need to look at the extent of coverage required and possible use of alternate test headforms. There is also a need to evaluate maximum acceptable g levels, since older riders and perhaps children may be more susceptible to injury, and some researchers believe that the current 300 g maximum limit is already too high for young adults. There is at present no differentiation for children vs. adults in drop height, headform weight or acceptable maximum g levels. There is also no testing of visors to see if they will shatter on impact or if they would snag and contribute to rotational injury. We need to look at the shape of the hemispheric impact anvil as well. In short, we have a long way to go in the standards area. The Z90 Committee is severely hampered by the lack of lab testing necessary to improve the standard and extend it to other parameters.
Look for a new ANSI Z90.4 standard sometime next year if you are an optimist.
Petition to CPSC for a Federal Bicycle Helmet Standard
A group of organizations led by the Consumer Federation of America as part of the Safe Kids campaign (and including BHSI and the Bicycle Federation among others) has petitioned the Consumer Product Safety Commission to adopt a Federal bicycle helmet standard. This will probably result in CPSC adopting the ANSI standard. That means that for the first time the ANSI standard could be policed, that bike shops could not sell hairnets and other aberrations, and that a shipment of junk helmets from abroad might not be permitted in. Unfortunately there are severe budgetary limits to what CPSC can do in this area. You can write to CPSC to support the petition (we have copies--$2). We'll also send you the Consumer Federation's info on how to write to Congress to support more funding for CPSC's operations.
BHSI Documentation Center Tops 200 Documents
The Bicycle Helmet Safety Institute Documentation Center now has available a total of 205 documents. Attached is an update of the bibliography you have already received adding 50 documents. Most of them are available from us. Please remember that where possible, we want the BHSI Documentation Center to be a two way street. We want to exchange documents--studies, articles, pamphlets, almost anything about helmets--with those who have things which are not on our list. The bibliography is being updated almost daily. You can get a new copy when needed by phoning or writing us.
1999 Note: BHSI closed the Documentation Center after putting up our Web server in 1995.
Wayne State Studying Sliding Resistance of Hard Shells vs. Soft Shells
Some of us suspect that soft shell helmets are "stickier" when they hit pavement than hard shells. In a high-speed crash they might increase rotational injury to the brain or strain the neck. Dr. Voigt Hodgson of Wayne State University in Detroit has set up an instrumented dummy crashing into slanted pavement to test the sliding resistance of hard shell vs. soft shell bicycle helmets and the effect on crash energy imparted to the dummy's head. Ron Brown, our Technical Director, and Randy Swart visited Dr. Hodgson's lab in April as the experiment was being set up. We do not yet have results from Dr. Hodgson's work, but are hopeful that it will measure the difference in sliding resistance at moment of impact and offer some basis for advising consumers on what to expect from either design. Meantime we are advising people that both designs do the basic job, but the hard shell is probably better if you crash while riding fast. We also emphasize the need for something like internal reinforcing or a thin shell on the outside to keep soft shell helmets from breaking up on initial impact.
BHSI Still Needs Funding for Our Test Rig and Other Encouragement
We are still actively seeking funding for our test laboratory If you can help with that we would like to hear from you. Actually, we would like to hear from you anyway. That will ensure that we stay in touch and that we will not drop you from the mailing list. If you are not in touch with us regularly, send us a new document to list or an endorsement letter, or a postcard from your vacation or something so we know you still care. Thanks!
This page was reformatted on: April 30, 2015.