<Strong>Procedure for production conformity testing</Strong>
1.
This appendix describes the procedure to be used to verify production conformity for the emissions of pollutants.
2.
With a minimum sample size of three engines, the sampling procedure shall be set out so that the probability of a lot passing a test with 30 % of the engines defective is 0,90 (producer's risk = 10 %) while the probability of a lot being accepted with 65 % of the engines defective is 0,10 (consumer's risk = 10 %).
3.
The following procedure is used for each of the emission pollutants (see Figure 2.1):
Let
n
the current sample number.
4.
Determine for the sample the test statistic quantifying the cumulative number of nonconforming tests at the nth test.
5.
Then:
If the test statistic is less than or equal to the pass decision number for the sample size given in Table 2.1, a pass decision shall be reached for the pollutant;
If the test statistic is greater than or equal to the fail decision number for the sample size given in Table 2.1, a fail decision shall be reached for the pollutant;
Otherwise, an additional engine is tested in accordance with point 6.2 and the calculation procedure shall be applied to the sample increased by one more unit.
In Table 2.1 the pass and fail decision numbers shall be calculated by means of the International Standard ISO 8422/1991.
<Emphasis>Table 2.1</Emphasis>
Test statistics for production conformity testing
| Minimum sample size: 3 | Minimum sample size for pass decision: 4 |
| Cumulative number of engines tested (sample size) | Pass decision number | Fail decision number |
|---|
| 3 | — | 3 |
| 4 | 0 | 4 |
| 5 | 0 | 4 |
| 6 | 1 | 5 |
| 7 | 1 | 5 |
| 8 | 2 | 6 |
| 9 | 2 | 6 |
| 10 | 3 | 7 |
| 11 | 3 | 7 |
| 12 | 4 | 8 |
| 13 | 4 | 8 |
| 14 | 5 | 9 |
| 15 | 5 | 9 |
| 16 | 6 | 10 |
| 17 | 6 | 10 |
| 18 | 7 | 11 |
| 19 | 8 | 9 |