GB/T 9169-2010 Determination of thermal oxidation stability of jet fuel — JFTOT method

Summary page. This page is a compiled excerpt/summary of the standard — it is not the full standard text and does not replace it. Verify every value against the official standard and the product certificate before use.

GB/T 9169-2010 specifies the determination of the thermal oxidation stability of jet fuel with the jet fuel thermal oxidation tester (JFTOT), and this page summarizes its identity, scope, results, apparatus, materials, sample quantities, key conditions, rating rules, reporting and precision.

Evidence note: a 14-section original historical learning card compiled from the 30-page original of the same edition, not the full standard text or a controlled operating procedure. This edition was abolished on 2023-12-01 and fully replaced by the 2023 edition; this card cannot replace the current edition. Technical review is pending; apparatus figures, colour standards and complete controlled operations have not been reconstructed; no calculator is provided, and no equivalence, product applicability, batch value or supply is inferred.

Identity, version and source: Original PDF pages 1, 3–4 and official version records. The original PDF cover number is GB/T 9169—2010, published 2011-01-10 and implemented 2011-05-01, replacing the 1988 edition; the year must not become 2011 because of the publication date. The identity of the original has been checked; this page does not publish the scanned original. The foreword is a modification adoption of ASTM D3241-08a; the structural and technical differences are given in the foreword and informative Annex A; no equivalence is inferred.

What is measured and the scope: Original PDF pages 5–6, Chapters 1 and 4. Chapter 1 assesses the tendency of jet fuel to form deposits in the engine fuel system and applies to jet fuels. Chapter 4 passes the fuel at a fixed flow through a temperature-controlled heated tube and a downstream precision filter, observing tube-wall deposits and filter blockage separately, and does not take a single differential pressure or colour as the whole result.

The two evidence chains of the result: Original PDF pages 6, 15–17, Clause 3.5 and Annex B. The main results are the visual rating of tube deposits and the filter differential pressure record. The discrete ratings of §3.5 are 0, <1, 1, <2, 2, <3, 3, <4, 4 and >4, 10 grades in total; continuous interpolation or simple colour averaging is not permitted. Abnormal A and peacock blue P are reported separately according to the rules of Annex B.

Apparatus, models and controlled operation: Original PDF pages 6–7, Chapter 5, Tables 1–2. Table 1 distinguishes 202, 203, 215, 230, 240 and 230 Mk III; pressurization, pump type and differential pressure recording device vary with model. The dedicated instrument, the heated tube assembly and the visual tube rater cannot be replaced by a summary. 5.3 states that the dedicated instrument participates in the definition of the method; operation must use the controlled manual for the corresponding model, and this card does not reconstruct interlock, assembly or maintenance procedures.

Materials and consumables evidence: Original PDF pages 7–8, informative Annex D. One test uses a new heated tube and a new test filter with a nominal pore size of 17 μm; fuel pre-filtration uses a separate 0.45 μm membrane, which must not be confused with the same filter. Cleaning involves specific clauses for toluene, acetone, trimethylpentane or n-heptane, and Annex D gives hazard warnings; no product packaging, stock, transport/storage or applicability relationship is inferred. The tube material described in Table 2 is 6061-T6 aluminium, with a magnesium to silicon mass ratio not exceeding 1.9:1 and an Mg₂Si content not exceeding 1.85%; the machined surface finish is 50 ± 20 nm, and per the original GB/T 6062 and GB/T 10610 the average of measurements over four 1.25 mm evaluation lengths is taken. This is the definition of the dedicated tube for this edition and cannot be generalized to all product specifications. The unique and consecutive number on each tube serves to identify the manufacturer and the raw material batch; website product models and item numbers must not be taken as the specific tube batch or certificate number on this basis. Original Table 2 item | Dimension/mm | Tolerance/mm Tube length | 161.925 | ±0.254 Middle section length | 60.325 | ±0.051 Shoulder outer diameter | 4.724 | ±0.025 Middle section outer diameter | 3.175 | ±0.051 Inner diameter | 1.651 | ±0.051 Total indicator deflection (maximum) | 0.013 | This row has no tolerance column value in the original table

Sample preparation and the difference in quantities: Original PDF pages 7–9, Chapters 7 and 8 and 11.1.3. Chapter 7 samples according to GB/T 4756, with container material and cleanliness per the original edition. §8.1 requires at least 450 mL for the test and about 50 mL for the system; §8.2 prepares 1 000 mL for filtration/aeration, and Table 2 separately mentions a 600 mL aerated sample and a 450 ± 45 mL test reservoir. The numbers belong to different actions or devices and are not merged into a single purchase specification. No more than 1 h from aeration to the start of heating (11.1.3).

Independent definition of key conditions: Original PDF pages 7–9, Table 2, Chapter 8, 11.1.2. §8.3 pressure 3.45 ± 0.345 MPa; 8.4 thermocouple located at 39 mm; 8.7 flow 3.0 ± 0.3 mL/min; 8.9 test time 150 ± 2 min. The control temperature of the test heated tube is determined by the original clause of the fuel specification/method used; calibration at 232 °C or 327 °C cannot replace the test temperature, still less serve as a product storage temperature. §11.1.2 retains 15–32 °C during aeration separately.

Checks, calibration and flow rate: Original PDF pages 9–11, 26–27, Chapters 10–11 and Annex E. The frequencies and model applicability in Chapter 10 must be checked in the controlled original and the manual. Check the flow rate at the beginning and in the last 15 min of the test, and normally record the differential pressure every 30 min. Annex E: 20 drops with a gear pump is 9 ± 1 s, 20 drops with a plunger pump is 19 ± 1 s; the volumetric referee method for a plunger pump gives 4 min 33 s to 5 min 33 s for 15 mL. Drop counts and pump types must not be interchanged, and the calibration alloy melting point is kept separate from the sample test temperature.

Tube wall colour rating: Original PDF pages 15–17, normative Annex B. Normative Annex B requires evaluation of the darkest area and rating by the maximum, and the deposit area must not be averaged. B.8.1 requires rejection of the tube if the pre-test defect area is greater than 2.5 mm²; B.9.2.1 rates only deposit bands or spots with an area greater than 2.5 mm² and a width greater than 0.8 mm after the test; the two rules must not be merged; P/A and normal colour coexisting have their own reporting rules. The colour standards, light box conditions and original figures are not reconstructed by this learning card.

Differential pressure and alarm boundaries: Original PDF pages 12, 19, Chapter 13 and C.2.2.3. Chapter 13 records the maximum differential pressure or the time at which 25 mmHg (3.3 kPa) is reached. The common alarm in C.2.2.3 is 125 mmHg (16.66 kPa), with a legible leading 1 on original PDF page 19. The alarm and reporting thresholds differ and must not be interchanged, and neither directly declares the sample acceptable. Maintenance checks in C/E have other conditions such as 100 mmHg and 50 mmHg, none of which are product limits added by this card.

Reporting and incomplete tests: Original PDF pages 11–12, 11.8.3, Chapter 13. Chapter 13 includes the heated tube control temperature, the deposit rating and the maximum differential pressure/time of specification; if 150 min is not completed, record the corresponding time and rating, and do not treat a termination as a complete normal test. Report the fuel consumption and the tube serial number. §11.8.3 states that the original edition considers the test invalid if the consumption is less than 405 mL; this differs from the 450 mL test quantity.

Precision and bias: Original PDF pages 12, 17, Chapter 14, B.11. The collaborative study background of original 14.1 cannot be converted into usable precision limits. 14.2 states explicitly that the results cannot be analysed by standard statistical classification methods and that precision cannot be determined; 14.3 reads literally that this property is defined only by this method, so the method has no bias; this is the method definition formulation and does not mean that actual measurement has no error or that any batch value is unbiased. The rating precision of B.11 is under determination. r/R, confidence intervals, batch assigned values or uncertainty must not be written independently.

Annex status and the break point: Original PDF pages 3–4, 28, foreword and Annex F. A, D, E and F are informative; B and C are normative. The F break point is the highest control temperature that meets the tube rating and differential pressure specification requirements; through a series of tests, x °C passes and x+5 °C fails, and x °C is reported accordingly. This explanation does not reconstruct a table look-up/equipment calculator, and does not provide current specifications or judgement for any sample.

References, gaps and review boundaries: Original PDF pages 5, 29, Chapter 2 and references. Chapter 2 lists GB/T 4756, GB/T 6062, GB 6537, GB/T 10610, GJB 560A and GJB 2376; the dated/undated references and adoption relationships follow the original edition, and the current status of these citations is not guessed. ASTM D4306 is listed separately in the references and is not merged with the normative references. The dimensions and tolerances below Table 2 were cross-checked line by line against original PDF page 7; the remaining figure-based equipment procedures, colour standards and independent technical acceptance still require verification. This learning card adds no product relationships, does not alter the 2023 page and does not publish the scanned original.

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