Standard

SAE J2189

Revised

Note: This standard has a new edition: SAE J2189

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Abstract

1. Scope--This document is set forth as an SAE Information Report, notas an SAE Recommended Practice, because of the general inexperience intesting the interaction between child restraint systems (CRS) anddeploying airbags and the lack of real-world accident data. Whenstatistically significant real-world data are available, in whichairbags have contacted a variety of child restraints, and there is moretesting experience with this interaction, it may be appropriate todevelop an SAE Recommended Practice. This document addresses only the effects of the interactions betweendeploying airbags and child restraint systems that would have beenconsidered properly installed and used in the right and center frontpassenger positions before the advent of passenger airbags and may beproperly installed there in the future. Child restraint misuse is nototherwise addressed in this document. During its inflation process, an airbag generates a considerable amountof kinetic energy and, as a result, substantial forces can be developedbetween the deploying airbag and the CRS. (For background on airbagdesign and deployment, see References 1 and 2.) Although there is verylittle experience with vehicles equipped with passenger airbags,preliminary laboratory tests have indicated that these forces can besufficient to produce serious injury to the CRS occupant. NHTSA hasrecommended that rear-facing child restraints of current design be usedonly in the rear seat of vehicles equipped with such airbags (Reference3). Even so, many children may be restrained in either rear- orforward-facing CRSs in the front seat of such vehicles, and the childand/or the CRS may interact with the airbag. These guidelines weredeveloped to improve the understanding of such interactions and to aidin the assessment of future designs. This document describes dummies, procedures, and configurations thatcan be used for investigating the interactions that occur between adeploying airbag and a CRS. Static tests may be used to sort CRS/airbaginteraction on a comparative basis in either an actual or a simulatedvehicle environment. Systems that appear to warrant further testing maybe subjected to an appropriate dynamic test at a speed near that neededto deploy an airbag or at a higher speed commonly used to evaluate CRSperformance. No test matrix is specified at this time for evaluatingeither a CRS or an airbag during interaction with each other. Instead,engineering judgment based on prior experience with CRS and/or airbagtesting should be used in selecting the tests to be conducted with eachindividual system. Such tests may be aimed not only at producinginteractions with the most severe results but also at identifying thoseconditions that produce the least interaction and/or satisfactory CRSperformance results. Baseline tests to indicate the performance of aCRS in the absence of airbag deployment are also recommended forcomparison purposes. Mild-severity and high-severity crash pulses are described in 7.2.These pulses are not vehicle-specific but represent generalacceleration-time histories for two crash conditions. The mild-severitypulse approximates a crash that would just deploy a typical airbag.This pulse would be used to evaluate the effect of the energy of thedeploying airbag when the CRS and dummy are exerting the least amountof inertial force in the forward direction, but the dummy and/or CRS ismoved forward by that inertial force. The high-severity pulse issimilar to that specified in FMVSS 213 to evaluate CRS performance andwould be used here to evaluate the airbag as an additional variable ina well-documented crash environment. These generic pulses or othervehicle-specific pulses may be used as appropriate. Differences inshape between the generic and the vehicle-specific pulses are expectedto be greater for the high-severity than the mild-severity, withcorresponding differences expected in dummy responses. This document encourages the use of a wide range of test configurationsand conditions, while recognizing that the range of possibleinteractions is essentially limitless and beyond testing capability.Further, measurements of primary importance for the variousconfigurations are given in Section 9, Table 1, but performance limitsare not specified. References 4 and 5 and SAE J885, SAE 840884, SAE826048, and SAE 841656 in Section 2 give some background on humanimpact tolerance and criteria, describe scaling techniques fordifferent-sized occupants, and offer interpretations of dummy responsesrelative to human injury potential that may be helpful in theevaluation. However, the 3-year-old-size child dummy used to obtain thedata in SAE 826048 and SAE 841656 has been extensively modified sincethese interpretations were given, so caution should be exercised indrawing conclusions from the responses of the modified dummy untilpossible differences have been verified. These and additionalbackground papers on airbag development and deployment can be found inSAE PT-31 and SAE SP-736.

Document information

  • Standard from SAE_AC
  • Published:
  • Version: 0
  • Document type: IS
  • Additional information
    • March 1993