[Federal Register Volume 60, Number 8 (Thursday, January 12, 1995)]
[Rules and Regulations]
[Pages 2896-2899]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-751]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
49 CFR Part 572
[Docket No. 95-01, Notice 1]
RIN 2127-AF48
Anthropomorphic Test Dummy; Six-Year Old Dummy
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation.
ACTION: Final rule; technical amendment.
-----------------------------------------------------------------------
SUMMARY: This document makes a minor correction to the thorax assembly
and test procedure in NHTSA's regulation for the six-year-old child
dummy. This document corrects inconsistencies between the figure in the
regulation that illustrates the test set-up for calibrating the dummy's
thorax and the regulatory text that describes the calibration test
procedure. This action removes potential sources of concern and
confusion for manufacturers and users of the dummy about whether a
particular six-year-old child dummy meets the specifications of NHTSA's
regulation for the dummy (part 572, subpart I).
EFFECTIVE DATE: The changes made in this rule are effective January 12,
1995.
FOR FURTHER INFORMATION CONTACT: Mr. Stan Backaitis, Office of Vehicle
Safety Standards, National Highway Traffic Safety Administration, 400
Seventh Street SW., Washington, DC 20590. Telephone: (202) 366-4912.
SUPPLEMENTARY INFORMATION: On November 14, 1991, NHTSA published a rule
that added specifications for a 6-year-old child test dummy to NHTSA's
set of regulations for ``Anthropomorphic Test Dummies'' (49 CFR part
572). The agency explained in the rule that the 6-year-old child dummy
would be used to test child restraint systems for older children. The
dummy is instrumented with accelerometers for measuring accelerations
in the head and thorax during dynamic testing. The rule adopted
performance criteria as calibration checks to assure the repeatability
and reproducibility of the dummy's dynamic performance. These
specifications for the dummy are set forth in subpart I of 49 CFR part
572.
In February 1994, First Technology Safety Systems, Inc. (First
Technology), a manufacturer of test dummies, informed the agency that
figure 41 in subpart I appears to have two errors. Figure 41
illustrates the test set-up for calibrating the dummy's thorax (figure
41, ``thorax impact test set-up''). Both errors are due to
inconsistencies between figure 41 and the regulatory [[Page 2897]] text
in subpart I that describes the test procedure for calibrating the
dummy's thorax (49 CFR section 572.74(c)(2)). In the calibration test,
the dummy's chest is impacted by a test probe at a specific point and
the accelerometer's measurements are evaluated.
First Technology described the first error thusly:
The thorax test procedure [of section 572.74] states that the
impact point should be 2.25 inches below the centerline of the
clavicle retaining screw. The impact point based on that dimension
would fall between the first and second rib. In contrast, figure 41
* * * shows the centerline of the impactor in line with the
centerline of the third rib.
The second error relates to how the dummy is positioned for the
thorax impact test. Section 572.74(c)(2) specifies that the dummy is
adjusted ``so that the longitudinal centerline of the No. 3 rib is
horizontal.'' In contrast, an instruction in figure 41 specifies that
the dummy is set up with the centerline of the number three rib
horizontal ``\1/2\ [inch].'' First Technology stated in its
letter, ``[T]he tolerance on figure 41 is \1/2\ inch, which
would result in 14 degrees variation.''
Technical Amendment
NHTSA has examined First Technology's concerns and agrees that
figure 41 and section 572.74 need to be amended so that they are
consistent. As to the first error, the correct specification for the
location of the impact point for the impactor is in section 572.74, and
not in figure 41. The centerline of the impactor and the centerline of
the third rib were drawn on figure 41 to be coincident instead of being
slightly apart. This makes it appear that the impactor's first contact
occurs at the centerline of the third rib, instead of approximately
1\3/8\ inch above it, in accordance with section 572.74. NHTSA is
correcting figure 41 to depict the centerline for the thorax impactor
as being slightly above the depicted centerline of the dummy's third
rib.
As to the second error, the instruction in figure 41 that specifies
that the dummy is ``set up with centerline of #3 rib horizontal
\1/2\ inch'' is inconsistent with the instruction in
section 572.74(c)(2) concerning dummy set-up. The regulatory text
states: ``adjust the dummy so that the longitudinal centerline of the
No. 3 rib is horizontal.'' The ``\1/2\ inch'' tolerance
provided in figure 41 is inconsistent with the regulatory text since
the centerline of the No. 3 rib of a dummy adjusted to the allowable
limit could be far from horizontal. On the other hand, NHTSA believes
that the tolerance should not be altogether eliminated. A 1 degree
tolerance in section 572.74(c)(2) would provide some flexibility while
ensuring that the centerline of the rib will be essentially, if not
exactly, horizontal. Accordingly, NHTSA amends section 572.74(c)(2) to
provide for 1 degree of tolerance. In addition, the
instruction in figure 41 that specifies the dummy is ``set up with
centerline of #3 rib horizontal \1/2\ inch'' is revised to
provide for the 1 degree of tolerance.
The regulatory text of section 572.74(c)(2) is also revised with
regard to its reference to the ``longitudinal centerline'' of the No. 3
rib as the portion of the dummy that must be horizontal. Using the word
``longitudinal'' is inaccurate, since ``longitudinal'' describes a
characteristic of a line, while what was actually meant was the
alignment of the dummy in a plane. To more accurately describe the
positioning of the dummy, the direction in section 572.74(c)(2) that
the ``longitudinal centerline of the No. 3 rib is horizontal'' is
changed to ``the plane that bisects the No. 3 rib into upper and lower
halves is horizontal'' (1 degree). This text is also added
to the instruction on positioning the dummy in figure 41.
NHTSA believes this rule is needed to avoid potential sources of
complaint and confusion. In the past, dummy manufacturers have urged
NHTSA to correct any inconsistency between the part 572 specifications
and the actual design and manufacture of the test dummies. (See, e.g.,
correction of NHTSA's regulation for the side impact test dummy, 59 FR
52089; October 14, 1994.) These manufacturers are concerned that
customers could complain that a dummy they purchased does not meet the
specifications of the part 572 regulation, even when the problems are
with the regulation rather than the dummy, and are relatively minor.
This document does not impose any additional responsibilities on
any vehicle or dummy manufacturer. NHTSA confirmed with several test
facilities that they locate the impactor according to section 572.74,
and not figure 41. Since this rule does not impose any additional
burdens, and because it corrects minor inconsistencies in the
regulation and removes potential sources of question for dummy
manufacturers, NHTSA finds for good cause that notice and an
opportunity for comment on this document are unnecessary, and that this
rule should be effective upon publication.
These minor technical amendments were not reviewed under E.O.
12866. NHTSA has considered costs and other factors associated with
these amendments, and determined that these amendments do not change
any of the conclusions in the November 1991 final rule regarding the
impacts of that final rule, including the impacts on small businesses,
manufacturers and other entities.
List of Subjects in 49 CFR Part 572
Motor vehicle safety.
In consideration of the foregoing, NHTSA amends 49 CFR part 572 as
follows:
PART 572--[AMENDED]
1. The authority citation for part 572 is revised to read as
follows:
Authority: 49 U.S.C. 322, 30111, 30115, 30117 and 30166;
delegation of authority at 49 CFR 1.50.
Subpart I--6-Year-Old Child
2. In Sec. 572.74, paragraph (c)(2) is revised to read as follows:
Sec. 572.74 Thorax assembly and test procedure.
* * * * *
(c) * * *
(2) Establish the impact point at the chest midsagittal plane so
that the impact point is 2.25 inches below the longitudinal center of
the clavicle retainer screw, and adjust the dummy so that the plane
that bisects the No. 3 rib into upper and lower halves is horizontal
1 degree.
BILLING CODE 4910-59-P
[[Page 2898]]
* * * *
* * *
3. Figure 41 in subpart I is revised to read as follows:
[GRAPHIC][TIFF OMITTED]TR12JA95.000
BILLING CODE 4910-59-C
[[Page 2899]] Issued on January 5, 1995.
Ricardo Martinez,
Administrator.
[FR Doc. 95-751 Filed 1-11-95; 8:45 am]
BILLING CODE 4910-59-P
