NB/SH/T 0868-2013 Determination of cleanliness of jet fuel — Portable automatic particle counter method

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Card type: Test method

1. Method number / full title / English title / replacement relationship

• Method number: NB/SH/T 0868—2013
• Chinese full title: Determination of cleanliness of jet fuel — Portable automatic particle counter method
• English title: Determination of the level of cleanliness of aviation turbine fuel—Portable automatic particle counter method
• Replacement relationship: not provided in the available source (the foreword only addresses the adoption relationship and does not list any replaced standard)
• Adoption relationship: modified adoption by the redrafting method of the Energy Institute standard IP 565/10 "Determination of cleanliness of aviation turbine fuels — Portable automatic particle counter method"
• Structural changes compared with IP 565/10: the warning in the scope is moved to the front; the clauses of Chapter 5 and Chapter 6 are swapped
• Technical differences compared with IP 565/10: use GB/T 4756 instead of IP 475 (see 7.1); add reference to GB/T 14039 instead of ISO 4406 (see 3.3); add content on the automatic shaking device (see 9.1)
• Editorial modifications: the standard title is changed to "Determination of cleanliness of jet fuel — Portable automatic particle counter method"; add the note after clause 7.1; in the references add IP 367 and IP 564, and use GB/T 18854 instead of ISO 11171
• Publication/implementation: published on 2013-06-08, implemented on 2013-10-01
• Issuing authority: National Energy Administration
• Secretariat: Subcommittee on Petroleum Fuels and Lubricants of the National Technical Committee for Standardization of Petroleum Products and Lubricants (SAC/TC280/SC1)
• Drafting organization: Sinopec Research Institute of Petroleum Processing
• Main drafter: Zhang Cuijun

2. Applicable scope and non-applicability

• Applicable to the determination of the degree of dispersion of dust particles and small water droplets with particle sizes from 4μm to 30μm in jet fuel.
• The maximum cumulative count per milliliter of sample that can be determined is 60000.
• Note 1: water droplets are treated as particles, and agglomerated particles are determined as a single blurred entity; only the projected area of the particles is measured, but the diameter is reported.
• Note 2: particle size refers to the particle size measured with the instrument described in GB/T 18854.
• Not applicable: no explicit non-applicability clause is provided in the available source.
• Warning: this standard involves certain hazardous materials, operations and equipment, but does not purport to address all safety problems; users should establish appropriate safety precautions before use and determine the applicability of relevant regulatory limitations.

3. Method principle

The sample is drawn from the sample container at 30mL/min, passes through the optical measurement chamber, and then enters the waste liquid container. The automatic test program first rinses the optical measurement chamber and tubing with 50mL of sample, followed immediately by three tests, each using 10mL of sample, and the final result given is the average of the three. Because particles/droplets entrained in the sample attenuate light, a voltage drop is produced; the voltage drop is proportional to the particle/droplet diameter. (At the end of this paragraph in the source, after "after the test is completed," the content is missing and requires confirmation against the source standard (source-text extraction))

4. Reagents and materials (purity / preparation)

• 6.1 Solvent containing medium test dust (MTD): purity and preparation details are not provided in the available source (source-text extraction missing, requires confirmation against the source standard (source-text extraction)).
• 6.2 n-Heptane: analytical reagent grade, filtered through a filter membrane with a nominal pore size of 0.45μm. The filtered n-heptane is stored in a container made of suitable material; the container must be rinsed three times with filtered n-heptane before use.
• 6.3 Filter membrane: cellulose or polycarbonate with a nominal pore size of 0.45μm.
• 5.3 Filtration device: a filtration device with a filter membrane of nominal pore size 0.45μm, used for filtering n-heptane.

5. Instruments and equipment

• 5.1 Portable automatic particle counter (APC): a portable or non-fixed instrument used in the laboratory; it includes an optical measurement chamber, an integral dual-head pump, an automatically switchable valve, an electron tube (the component name is unclear in the source transcription; the exact tube type remains unverified), and software for analyzing, displaying and measuring data (see Annex A). Instrument calibration can be traced to initial equipment calibrated according to the method of GB/T 18854.
• 5.2 Sample container: cylindrical, made of glass or plastic, with a volume of at least 125mL; a lid with a suitable inner sealing ring must be selected; a glass container should be used to avoid particles adhering to the inner wall of the container due to static electricity generated by certain samples; ensure that the test sample is above the bottom of the container by 10mm.
• 5.3 Filtration device: filter membrane with a nominal pore size of 0.45μm, used for filtering n-heptane.
• Automatic shaking device (see 9.1, the foreword mentions this newly added content).
• Annex A Instrument composition: A.1.1 the instrument consists of an optical measurement cell connected to a computer that controls a dual pump system through an automatic switching valve; A.1.2 the automatic switching valve enables test rinsing and measurement to be carried out automatically under computer control and maintains unidirectional sample flow (directly from the test container into the optical measurement cell); A.1.3 the dual pump is computer-controlled and driven by a constant-speed motor, ensuring a nominal constant flow rate of 30mL/min through the optical measurement cell; A.1.4 the optical measurement cell consists of an optical sensor and a laser diode light source of 5mW and wavelength 670nm±5nm; A.1.5 the delivery tube installation includes transparent flexible tubing on the connector and a cover to prevent dust from entering, etc. (part of source-text extraction is missing, requires confirmation against the source standard (source-text extraction)).

6. Recommended operating conditions

• Flow rate: 30mL/min (see 4, 10.2.2, A.1.3).
• Rinsing: the automatic test program first rinses the optical measurement chamber and tubing with 50mL of sample (see 4, 11.6).
• Testing: three tests, each using 10mL of sample, and the result is the average of the three (see 4, 11.6).
• Operating mode: ensure that the operating mode is selected as the R mode (see 8.2, the wording of source-text extraction is incomplete, requires confirmation against the source standard (source-text extraction)).
• Pre-test checks (performed automatically): light source on, light source intensity, sensor status, power supply voltage; the mode is also displayed in the printed results (see 8.3).
• Blank test: when the count of ≥4μm particles in the tested sample exceeds 20000 particles/mL, rinse the system with filtered n-heptane before the next sample and carry out a blank test according to steps 11.3 to 11.6; the ≥4μm particle count in the blank test should be less than 50 particles/mL (see 11.7 and the note).

7. Sampling and sample preparation

• 7.1 Unless otherwise specified, sampling is generally carried out in accordance with GB/T 4756 and the additional requirements of 7.2 and 7.3, and at least 125mL of sample is taken. Note: the sample should be tested as soon as possible to avoid changes in the sample due to prolonged standing.
• 7.2 The sample container must not introduce contamination into the sample; the container should be selected as an epoxy resin-lined metal container, an amber glass bottle, or a polytetrafluoroethylene (PTFE) container.
• 7.3 Before filling, the sample container must be rinsed at least three times with the sample to be tested.
• 9.1 Sample preparation: invert and shake the sample container no fewer than 60 times (manually or with an automatic device).
• 9.2 Use a clean sample container, or a container whose interior has been rinsed three times with the sample to be tested, or a sample container thoroughly cleaned with filtered n-heptane (see 6.2), and then dry it in a clean environment.
• 9.3 Pour the shaken sample into the sample container, then cover with a clean lid (the source has source-text extraction missing, requires confirmation against the source standard (source-text extraction)).
• 9.4 Ensure that at least 10% of sample remains in the container after the test is completed.
• 11.1 Before the test begins, invert and shake the sample with the sample mixer according to 9.1 to 9.3 for at least 1min (about once per second). Note: to prevent (source-text extraction missing, requires confirmation against the source standard (source-text extraction)), do not shake the sample too vigorously.
• 11.2 If only this test is to be performed, and both the sample container and the sample volume meet the requirements, it is permissible to sample directly from the sample container. Note: sampling directly from the sample container reduces the possibility of local contamination entering the sample, but because it may cause contamination, the sample is then unsuitable for other tests.
• 11.3 Ensure that the clean sample delivery tube remains below the fuel surface after about 80mL of sample has been used for the test.
• 11.4 Ensure that the sample delivery (tube does not touch) the wall or bottom of the sample container (the wording of source-text extraction is incomplete, requires confirmation against the source standard (source-text extraction)).

8. Analytical procedure

• 8.1 Follow the instrument manufacturer's (instructions) (source-text extraction missing, requires confirmation against the source standard (source-text extraction)).
• 8.2 Ensure that the operating mode is selected as the R mode (the wording of source-text extraction is incomplete, requires confirmation against the source standard (source-text extraction)).
• 8.3 During the test, the following checks are performed automatically before analysis: light source on, light source intensity, sensor status, power supply voltage; the mode is also displayed in the printed results. If any of the above checks does not pass, APC (the source is interrupted, requires confirmation against the source standard (source-text extraction)).
• 8.4 To ensure the cleanliness of the metal sample inlet tube (and the production delivery tube installation part), its exterior must be rinsed with filtered n-heptane before each test.
• 8.5 Before any routine test begins, start the measurement according to the procedure described in Chapter 11 (source-text extraction missing, requires confirmation against the source standard (source-text extraction)); inject at least 120mL of filtered n-heptane into a clean sample container and proceed according to the procedure in Chapter 11.
• 11.5 Start the automatic test program according to the instrument manufacturer's (instructions).
• 11.6 The dual-head pump draws 50mL (sample rinse) through the delivery tube and optical measurement chamber; then each time it draws 10mL of sample into the optical measurement chamber for measurement; the results of the three tests and the average are printed. Note 1: the results can be permanently stored and reproduced on a personal computer or other computing device. Note 2: among the three test results, when the difference in (particle count) data for ≥4μm exceeds 10% or 200 particles/mL, it may indicate a problem with sample introduction.
• 11.7 When the particle count of ≥4μm in the tested sample exceeds 20000 particles/mL, before testing the next sample, the system shall be flushed with filtered n-heptane (see 6.2), that is, a blank test shall be carried out according to the steps of 11.3 to 11.6, to avoid cross-contamination between samples. Note: When filtered n-heptane is used to test the measurement chamber and connected tubing, the particle count of ≥4μm in the test result should be less than 50 particles/mL; if it is greater than 50 particles/mL, it indicates that the measurement chamber and connected tubing are contaminated or the n-heptane is contaminated.
• 11.8 Record the sample number as required.

9. Qualitative and Quantitative Determination and Calculation Formulas

• 12.1 Cumulative count: the number of particles per milliliter of sample with particle sizes ≥4μm, ≥6μm, ≥14μm, ≥21μm, ≥25μm and ≥30μm (particles/mL).
• 12.2 ISO grade code: according to the expression method of GB/T 14039, the corresponding codes for the three preset particle sizes, which are ≥4μm, ≥6μm and ≥14μm respectively (see the note in 10.2.1).
• 3.2 Definition of cumulative count: the total number of particles per milliliter of sample passing through each preset particle size channel (≥4μm, ≥6μm, ≥14μm, ≥21μm, ≥25μm and ≥30μm).
• 3.3 Definition of ISO grade code: according to the result expression method specified in GB/T 14039, that is, x/y/z, where x, y and z are respectively the codes corresponding to the number of particles per milliliter of sample with particle sizes ≥4μm, ≥6μm (original text "≥Oum", requires confirmation against the source standard (source-text extraction)) and ≥14μm.
• 3.1 Definition of particle size: the equivalent diameter of the projected area of particles passing through the detection chamber, expressed in micrometers (μm).
• Calculation formula: not provided in the available source (the precision table 1 gives the calculation formulas for r and R, see Section 10).

10. Precision

• 13.1 Overview: The precision data given in 13.2 and 13.3 come from an interlaboratory comparison test in the year 2007, using 7 instruments, 7 operators and a sample set containing 10 jet fuels, with statistical analysis carried out with reference to the IP 367 procedure; because particles may be introduced during sampling and transportation, this study was conducted in one location; the bias of the statistical analysis was also correlated with IP 564. The reliability of test results shall be judged at the 95% confidence level.
• 13.2 Repeatability r: The difference between two test results obtained by the same laboratory, the same operator, using the same instrument, on the same sample shall not be greater than the value in Table 1.
• 13.3 Reproducibility R: The difference between two single and independent test results obtained by different operators in different laboratories, using different instruments, on the same sample shall not be greater than the value in Table 1.
• Note 1: Because the cumulative particle counts in these particle size ranges are quite small, and because of sample handling related to particle sedimentation, the precision values for the particle size ranges ≥21μm, ≥25μm and ≥30μm are poor; this also leads to the reproducibility results for the two largest particle size ranges (≥25μm and ≥30μm) failing to meet the normally acceptable minimum degrees of freedom of 30 recommended by IP 367.
• Note 2: Because the process of associating with the ISO grade code after rounding is carried out in a non-normal (non-Gaussian) manner, the calculation of repeatability and reproducibility for the ISO grade code is statistically invalid; the ISO grade code is widely used in industry because it is simple and easy to use; for indicative precision values see Appendix B, for reference only.

Table 1 Precision

Note: x is the average value of the cumulative particle count per milliliter of sample.

• Appendix B (Informative Appendix) Precision corresponding to ISO grade: B.1 overview follows the spirit of 13.3 Note 2; the judgment rules for B.2 repeatability and B.3 reproducibility (R) are the same as 13.2 and 13.3; the values in Table B.1 source-text extraction are severely missing (only fragments such as 1.025, 1.025, 11.373 are seen), requires confirmation against the source standard (source-text extraction).

11. Report

• 12 Report: The report shall print or display the final result for each milliliter of sample (the average of three tests).
• 14 The test report shall include the following contents: a) reference to this standard; b) the type of product tested and the complete label; c) test date and time; d) test results obtained from 12.1 and 12.2; e) deviations from the procedure as agreed or specified.
• In case of dispute, the instrument model used and the installed software version shall also be reported.
• Appendix C (Informative Appendix) Typical example of determination and result format: gives fields such as jet fuel (instrument mode), software version, time and date, operator, sample name, standard version, measurement volume 10mL, dilution ratio/%, etc.; example of cumulative counts for 3 tests (particles/mL): ≥4 is 2101/2051/2055, ≥6 is 295/280/265, ≥14 is 38/37/36, ≥21 is 12/13/11, ≥25 is 7/ (missing)/(missing), ≥30 is 2/2/ (missing); average values 2069, 280, 37, 12, 7, 2; ISO grade code 18/15/12.

12. Referenced Documents

• GB/T 4756 Petroleum liquids — Manual sampling (GB/T 4756—1998, eqv ISO 3170:1988)
• GB/T 14039 Hydraulic fluid power — Fluids — Method for coding the level of contamination by solid particles (GB/T 14039—2002, ISO 4406:1999, MOD)
• References:
  • [1] GB/T 18854 Hydraulic fluid power — Calibration of automatic particle counters for liquids (GB/T 18854—2002, ISO 11171:1999, MOD)
  • [2] IP 367 Determination and application of precision data in relation to methods of test
  • [3] IP 564 Determination of the level of cleanliness of aviation turbine fuel - Laboratory automatic particle counter method

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick Reference for Questions and Answers