Document ID: chunk:federal_register_of_legislation:F2012C00283:reg:21:p23
Version: federal_register_of_legislation:F2012C00283
Segment Type: reg
Provision Reference: reg 21 (pt 23/39)
Character Range: 320326–323460

of similar effect. Alternatively nullification of static effects may be achieved through equalisation of the static charge.
              1.3.4.4. A test filter shall be removed from the chamber no earlier than an hour before the test begins.
              1.4. Recommended System Description
               Figure 12 is a schematic drawing of the recommended particulate sampling system. Since various configurations can produce equivalent results, exact conformance with this figure is not required. Additional components such as instruments, valves, solenoids, pumps and switches may be used to provide additional information and co-ordinate the functions of component systems. Further components that are not needed to maintain accuracy with other system configurations may be excluded if their exclusion is based upon good engineering judgement.

Figure 12
Particulate Sampling System

               A sample of the diluted exhaust gas is taken from the full flow dilution tunnel DT through the particulate sampling probe PSP and the particulate transfer tube PTT by means of the pump P. The sample is passed through the particle size pre-classifier PCF and the filter holder(s) FH that contain the particulate sampling filter(s). The flow rate for sampling is set by the flow controller FC.
              2. Calibration and verification procedures
              2.1. Flow Meter Calibration
               The Technical Service shall ensure the existence of a calibration certificate for the flow meter demonstrating compliance with a traceable standard within a 12 month period prior to the test, or since any repair or change which could influence calibration.
              2.2. Microbalance Calibration
               The Technical Service shall ensure the existence of a calibration certificate for the microbalance demonstrating compliance with a traceable standard within a 12 months period prior to the test.
              2.3. Reference Filter Weighing
               To determine the specific reference filter weights, at least two unused reference filters shall be weighed within 8 hours of, but preferably at the same time as, the sample filter weighings. Reference filters shall be of the same size and material as the sample filter.
               If the specific weight of any reference filter changes by more than ±5µg between sample filter weighings, then the sample filter and reference filters shall be reconditioned in the weighing room and then reweighed.
               The comparison of reference filter weighings shall be made between the specific weights and the rolling average of that reference filter's specific weights.
               The rolling average shall be calculated from the specific weights collected in the period since the reference filters were placed in the weighing room. The averaging period shall be at least 1 day but not exceed 30 days.
               Multiple reconditioning and reweighings of the sample and reference filters are permitted until a period of 80 h has elapsed following the measurement of gases from the emissions test.
               If, prior to or at the 80 h