Evaluation of Precision for the ASTM E648-91A Standard Test Method for Critical Radiant Flux of Floor-Covering Systems.
Evaluation of Precision for the ASTM E648-91A Standard
Test Method for Critical Radiant Flux of Floor-Covering
Systems.
(428 K)
Lawson, J. R.
NISTIR 4799; 34 p. August 1992.
Sponsor:
Carpet and Rug Institute, Dalton, GA
Available from:
National Technical Information Service
Order number: PB92-238682
Keywords:
floor coverings; ASTM E 648; carpets; critical radiant
flux; fire tests; flammability; interlaboratory
evaluation; precision
Abstract:
The primary goal of this project was to develop data to
be used in writing a precision statement for the newly
revised ASTM E 648 test procedure. Revisions to the
standard included the use of a new line pilot burner,
improved control over air flow through the test chamber
and an extended chamber equilibration time before the
apparatus is calibrated. An interlaboratory test
program was conducted to develop the precision data. In
this study, seven laboratories performed tests on seven
sets of flooring materials. Six carpets and one
resilient flooring material were selected for the
evaluation. The interlaboratory study was designed and
carried out using procedures recommended in ASTM E 691
standard on interlaboratory studies. Results from the
program show that precision for the revised ASTM E 648
method is generally well within the range expected for
standard fire test procedures. Coefficients of
variation for repeatability ranged from 2.2 to 19.7
precent, and coefficients of variation for
reproducibility ranged from 3.6 to 25.2 percent. In
addition to these findings, a carpet variability problem
apears to have been identified. A large variation in
test results for two carpet products appears to be
associated with carpet non-uniformity. Recommendations
are made for research to develop an understanding of the
variations associated with the specific style of
carpeting. Recommendations are also made for studies to
further improve the test standard.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899