NOCSAE Consensus Body Approves Field Hockey Headgear and Ball Standards
Digital or analog data acqusition systems Discussion
August 7, 2013
Digital or analog data collection for NOCSAE certification testing?
There appears to be some confusion among laboratories that desire to use computer software driven digital data acquisition systems for NOCSAE standard testing. The desirability of using a computerized digital system versus an analog system is unquestionable; this approach can sometimes streamline the reporting process. Digital systems have been shown to be capable of accuracy and repeatability at least equal to that of analog systems in many applications.
There is no question that digital acquisition systems can be designed for use in NOCSAE drop test standards that are demonstrably capable of providing Severity Index and Peak g results equivalent to the KME data acquisition system currently specified by NOCSAE across the range of critically important Severity Index results.
NOCSAE standards require that the user of equipment that has not been specifically called out in NOCSAE documents, including electronic data acquisition systems as well as mechanical systems, must demonstrate that the use of such equipment is equivalent and provides test results that are in agreement with the equipment that is currently specified in the NOCSAE standards, across the critical range. Currently the critical range is 300-2000 SI with particular emphasis at the 1200 SI pass/fail level.
The central component of the NOCSAE test systems are the NOCSAE headforms which must be calibrated in a very specific manner in order to verify its response when impacted on a verified 3” calibration MEP and when impacted with a projectile in accordance with NOCSAE docs ND001 and ND021.
In order to design a digital data acquisition system to correctly calibrate a NOCSAE headform to obtain the desired responses, careful consideration must be taken on how the analog system processes the accelerometer signals to accomplish the calibration. It turns out that this is not a trivial task and requires development of sophisticated software programing along with quality digital hardware systems.
NOCSAE has developed such a system that has been in use for many years with an update about to be released in the coming months. Of note this system is only for use in limited drop testing applications.
It has been and remains a desire of NOCSAE to implement a more automated digital data acquisition system that is capable of accurately replicating the results of the current analog system for all NOCSAE testing. The current technical challenge is projectile impacts. In projectile impacts the analog system is able to collect all data from each channel in real time. While this is an antiquated approach in the eyes of some, in many ways the speed of this approach is critical to the results in short time duration events. It may be possible to create a digital system for these events, but it requires very high speed and high quality digital acquisition equipment capable of simultaneous signal sampling. Such systems are currently cost prohibitive.
Towards this end, SIRC is working with developers on a digital system that we hope to validate in the near future.
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Projectile Impact Test Method-effective date extension
The Board voted in June 2013 to change the effective date of ND021-12m13 (Projectile Impact Testing Method and Equipment Used in Evaluating the Performance Characteristics of Protective Headhear, Faceguards or Projectiles) to no earlier than June 2014.
Youth football helmet moved from “proposed” to “draft”
After deliberation and consideration of input from multiple interested parties, the board voted in January 2012 to change the Youth Football Helmet Standard from “Proposed” to “Draft” so that more input can be received, and to permit development of that standard to follow a separate track. There was also concern that some may misinterpret the “proposed” status to indicate that NOCSAE has reached a tentative final decision with regard to the content and parameters of that standard, which is not the case. Significant hurdles remain to the development of a youth football helmet standard that will address the specific injury risks and biomechanical forces involved in youth football, and that data has not yet been well developed. Recently published studies such as Daniel RW, Rowson S, Duma SM. Head Impact Exposure in Youth Football. Annals of Biomedical Engineering. 2012:1-6 is an example of the data being developed. And other programs focused specifically on injury epidemiology in youth football, some directly funded by NOCSAE research grants, are still in the data collection and analysis stage, and will provide additional science necessary to support an effective and reliable performance standard for youth football helmets. A Draft version of the standard is available here ND006-11m11
Standard performance specification for newly manufactured baseball/softball fielder’s headgear moved to final status
The Board also voted in January 2012 to move to Final Status Standard Performance Specification For Newly Manufactured Baseball/Softball Fielder’s Headgear. ND029-11m11 (Effective no earlier than January 2013)
Board approved clarifications to Quality Control and Quality Assurance provisions in ND001-11m12
In June 2012, the Board approved changes to ND001-11m12 that clarify the mandates required by all NOCSAE standards regarding the acceptable level of Quality Assurance, Quality Control and sample certification testing procedures necessary for certification of equipment to NOCSAE standards. (Effective no earlier than June 2013) These changes are intended to allow manufacturers some discretion as to how they accomplish the quality control and quality assurance levels requried by the standards.
Low level impact requirement added along with a change to drop height requirement.
At the January 2011 meeting, the Board approved the addition of a low level impact requirement for newly manufactured football helmets. Also the current drop height test requirement for all NOCSAE specifications was changed to measure the drop velocity. This caused a revision of the following numerous standards found here which are effective February 2012.
Continued review and research to proposed changes on helmet linear impactor test standard
The Board continues to review and research the proposed changes to the helmet linear impactor test standard, which is currently identified as ND081-04m04 and it remains in proposed status.