SH/T 0248-2006 Determination of cold filter plugging point of diesel and domestic heating oils

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.

SH/T 0248-2006 specifies the determination of the cold filter plugging point of distillate fuels used in diesel engines and domestic heating installations, and this page summarizes its historical identity, scope, principle, reagents, apparatus, cooling conditions, sampling, calibration, test procedure, reporting and precision.

Evidence note: historical study material for the 2006 edition, which the 2019 record explicitly replaces; the old status entry conflicts. Not the full standard text or an operating procedure, technical review is pending, and the specific applicability and figures remain to be verified.

Method identity and historical version: Original PDF 1–3, cover and foreword; official 2006/2019 records. SH/T 0248-2006, Determination of cold filter plugging point of diesel and domestic heating oils. The original cover gives publication on 2006-05-13 and implementation on 2006-11-01, replacing SH/T 0248-1992. The foreword states modification adoption of IP 309/99, and standard equivalence is not inferred. This page is historical study material for the 2006 edition. The official 2019 record explicitly states full replacement of this edition, implemented on 2020-05-01; the old 2006 entry still shows current, and this status conflict is retained, so the old entry alone cannot establish that this edition still applies to a current task. Specific contracts, products and accreditation scopes must be checked separately, and this page does not replace the 2019 edition.

Scope and use boundaries: Original PDF 4, Chapter 1. The object is distillate fuels used in diesel engines and domestic heating installations, which may contain flow improvers and other additives. Both manual and automatic instruments fall within the scope of this edition. The result evaluates the low-temperature filterability of the fuel under specified conditions and cannot directly guarantee the minimum operating temperature of all engines or heating systems. The installation of the equipment filter, and the difference between pour point and cold filter plugging point, affect the interpretation of use. Hazardous materials and operations are involved, and actual work requires a separate controlled safety procedure.

Principle and end point: Original PDF 4–5, Chapters 3–4. The sample is cooled stepwise and drawn under controlled vacuum through a specified filter into a pipette; the flow and return are observed repeatedly after each 1 °C decrease. The cold filter plugging point is recorded as the temperature at the start of suction when the trigger conditions occur, including a time greater than 60 s for 20 mL of sample to pass, or the liquid failing to return completely by gravity. The set temperature of the cooling bath must not be taken as the cold filter plugging point of the sample.

Reagents and verification materials: Original PDF 5, Chapter 5. This edition lists n-heptane and acetone, both analytical grade, and also lint-free filter paper and calibration standards. Cleaning and sample pre-filtration have different uses and are not interchanged. The original gives no specific product item numbers, batch values or supply relationships that could be confirmed from it; this page adds no product applicability commitment.

Apparatus composition and key components: Original PDF 5–8, Chapter 6 and 12–19, Figures 1–8. The manual system consists of the test jar, jacket, insulation and positioning parts, thermometer, pipette and filter, cooling bath, three-way valve and vacuum regulating device; the automatic system also contains detection and control devices. The 45 mL mark of the test jar is for filling the sample, and the 20 mL ± 0.2 mL mark of the pipette is for observing the end point; the two have different uses. The filter mesh has a pore size of 45 μm, and the old mesh number of the 1992 edition is not used instead. The dimensions of Figures 1–8 and the complete assembly of parts have not been reconstructed and are not used for equipment manufacture or verification.

Cooling conditions and distinction of quantities: Original PDF 7, Table 1 and 6.1.12–6.1.14. Table 1 is the cooling bath arrangement of this edition; it is not a product storage temperature. When several jackets are in the same bath, the jacket walls are at least 50 mm apart; when only a refrigerating device is used, it should reach the next temperature point within 2.5 min. The vacuum source air flow is 15 L/h ± 1 L/h; the water column difference of 200 mmH₂O ± 1 mmH₂O is a pressure control condition and must not be written as the sample height. The stopwatch has a resolution of 0.2 s or better and an accuracy of 0.10% within 10 min. Expected cold filter plugging point | Cooling bath temperature arrangement Above −20 °C | −34 °C ± 0.5 °C −20 °C to −35 °C | −34 °C ± 0.5 °C, then −51 °C ± 1.0 °C Below −35 °C | −34 °C ± 0.5 °C, then −51 °C ± 1.0 °C, finally −67 °C ± 2 °C

Sampling and sample preparation: Original PDF 8, Chapters 7–8. Unless otherwise specified, sample according to GB/T 4756 as cited by this edition. Sample preparation is carried out at a room temperature not below 15 °C, and 50 mL of sample is pre-filtered through dry lint-free filter paper. The 50 mL pre-filtered and the 45 mL filled into the test jar must be distinguished; this page does not use this room temperature condition to infer storage or opening restrictions for a specific product.

Preparation, cleaning and calibration: Original PDF 8–9, Chapter 9. Both manual and automatic instruments require calibration at least twice a year; where appropriate, certified reference materials are used and checks are made with working standards of known cold filter plugging point according to a schedule. A check difference exceeding repeatability or a QC anomaly requires further investigation. After cleaning, the manual system must be dried and the connections, filter and seals and thermometer calibration checked; automatic instruments must be treated together with the manufacturer's instructions. The temperature indicator and platinum resistance thermometer are verified at least once a year. The complete cleaning safety procedure and calibration acceptance rules must be confirmed from the actual controlled documents.

Manual and automatic procedures: Original PDF 9–11, Chapter 10. This edition fills 45 mL, and the sample is placed in the appropriate apparatus at 30 °C ± 5 °C; when the cloud point is known, start from 5 °C above it. The manual method repeats suction and return observation after each 1 °C decrease, and the suction time and return behaviour must not be merged into a single timing judgement. When the sample has cooled to −20 °C without reaching the end point, transfer to the −51 °C ± 1 °C bath; when it has cooled to −35 °C without reaching the end point, transfer to the −67 °C ± 2 °C bath. Automatic instruments must also check the case of incomplete return; where the lower photosensitive element is absent, the original requires observing the corresponding return according to the manual steps and reporting it. This section is a principle learning summary, not a directly executable operating procedure.

Results and the low-temperature no-blockage report: Original PDF 10–11, 10.1.11–12 and Chapter 11. Report the cold filter plugging point as the sample temperature at the start of the suction that meets the end point condition. Even if the time to fill 20 mL is less than 60 s, if the liquid cannot return completely by gravity, the reading is still judged according to the rules of this edition. When the end point is still not reached after cooling to −51 °C, the original requires stopping and reporting not blocked at −51 °C; this must not be filled in directly as cold filter plugging point = −51 °C. Abnormal suction in automatic and manual operation requires retaining the original records and the test differences.

Precision and formula boundaries: Original PDF 11, Chapter 12 equation 1 and PDF 20, Figure 9. At the 95% confidence level of this edition, the difference between two consecutive results by the same operator on the same instrument under the same conditions should not exceed 1 °C. The reproducibility expression for independent results from different laboratories is R = 0.103 × (25 − X), where X is the mean of the two results compared, in °C. The note to Figure 9 states that the samples used to establish the precision had a cold filter plugging point not lower than −35 °C, so this precision cannot be extended to the not-blocked report at −51 °C or to all colder samples. Method repeatability/reproducibility is not product batch uncertainty; this page provides no on-machine judgement or calculator.

Test report checklist: Original PDF 11, Chapter 13. The report should retain at least the product type and number, the test method used, the sampling procedure, the result, any deviation from the specified procedure and the test date. The method number in the report must distinguish the 2006 and 2019 editions, and the year must not be omitted because the names are the same. A method learning page alone does not mean that a specific product has the corresponding certificate or applicability.

References, original and unverified items: Original PDF 4, Chapter 2 and all 20 pages. This edition cites GB/T 514, GB/T 4756 and GB/T 6003.1; the versions and adoption relationships involved in the latter two follow the original pages of this edition, and a citation record does not mean that the current version has been checked. This learning card is compiled from the 20 physical pages of the original scan of the same edition. In the bound volume the printed pages after 37 are 39–57, and the scan held does not include page 38; the actual body Chapters 1–13 and Figures 1–9 have been located, and a jump in page numbers alone cannot be used to assert that technical text is missing or that the text is complete. The dense figure dimensions, component tolerances, complete controlled manual and automatic operations and actual technical applicability still require review; the original scans are not published, and figures or product relationships are not guessed.

Direct answers to common questions: Original PDF 4, 7, 10–11, 20. Is the cold filter plugging point the cooling bath temperature? No, it is the sample temperature corresponding to the report and end point conditions. Can not blocked at −51 °C be written as a cold filter plugging point of −51 °C? No, the not-blocked report specified by this edition should be retained. Do 45 mL and 20 mL conflict? The former is the sample fill of the test jar, the latter the observation mark of the pipette. Can the precision be used as product uncertainty? No; its collaborative study range is also limited to not lower than −35 °C.

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