while ( <> )
{
    my @in_range = grep { /^[\d.+-]+$/ &&
                          296.1 <= $_ && $_ <= 314.0 } split /,\s*/;
    # skip records with only 305.1 (room temp kelvin?) in range
    next if @in_range == 1 && approx_equal( $in_range[0], 305.1 );
    print;
}