Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This document is developed in accordance with the rules given in GB/T 1.1-2020 Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents.
This standard replaces GB/T 261-2008 Determination of flash point - Pensky-Martens closed cup method, with respect to which, the following main technical changes have been made in addition to structural adjustment and editorial changes:
a) the scope is changed from "applicable to samples with flash point higher than 40℃" to "applicable to samples with flash point in the temperature range of 40℃ to 370℃" (see Chapter 1; Clause 1 of Edition 2008);
b) the expression that Procedure A is applicable to biodiesel blends samples is added in the scope (see Clause 1);
c) Procedure C, which is applicable to BD100 biodiesel samples, including scope, sampling, test conditions, test procedures and precision, is added (see Clauses 1, 8, 10 and 13);
d) contents related to some apparatus are modified and added, including the requirements for built-in pressure gauges, barometers, temperature measuring devices and explosion-protected ovens of automated apparatus and the installation positions of apparatus (see Clause 6; Clause 6 of Edition 2008);
e) contents of sampling and sample treatment are partially refined and supplemented (see Clause 8; Clause 8 of Edition 2008);
f) the atmospheric pressure range for accurately correcting the flash point in the flash point correction equation is expanded (see Clause 11; Clause 11 of Edition 2008);
g) the tolerance value of verification reference materials is added in Annex B, Table B.1 (see Annex B);
h) in order to cooperate with the use of automatic temperature measuring device, Annex D "Thermometer adapter" in GB/T 261-2008 is deleted, and contents related to electronic temperature measuring equipment are added (see Annex D, D.1).
This standard is modified in relation to ISO 2719: 2016 Determination of flash point - Pensky-Martens closed cup method.
This standard is changed from ISO 2719: 2016 in structure; the comparison between this standard and ISO 2719: 2016 in clause number is listed in Annex A.
The main technical differences with respect to ISO 2719: 2016 and their justifications are as follows:
——the adjustments on technical differences have been made for the normative references of this standard to adapt to the technical conditions in China, which are mainly reflected in Clause 2 "Normative references”, with the following specific content:
? ISO 15528 is replaced by GB/T 3186 which is identical to the international standard (see 8.1);
? ISO 3170 is replaced by GB/T 4756 which is modified in relation to the international standard (see 8.1);
? ISO 1513 is replaced by GB/T 20777 which is identical to the international standard (see 9.2);
? ISO 3171 is replaced by GB/T 27867 which is identical to the international standard (see 8.1).
The following editorial changes have also been made in this standard:
——in order to be consistent with the expression of product standards, "FAME (B100)" is changed to "BD100 biodiesel";
——in order to meet the actual needs of China, the note "This standard may also be applicable to jet fuels with flash point below 40℃" and the note on the applicability of used lubricating oil are added in the scope;
——in order to meet the actual needs of China, the note "The reproducibility herein is not applicable to 20# aviation lubricating oil" is added to the precision;
——for references, the corresponding international standards are replaced by Chinese standards which have consistent correspondence with international standards.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This standard was proposed by and is under the jurisdiction of National Technical Committee on Petroleum Products and Lubricants of Standardization Administration of China (SAC/TC 280).
The previous editions of this document are as follows:
——this standard was firstly issued as GB 261-1964 in 1964, firstly revised in 1977, secondly revised in 1983, and thirdly revised in 2008;
——this edition is the fourth revision.
Introduction
Flash point values are used in shipping, storage, handling, and safety regulations, as a classification property to define “flammable” and “combustible” materials. Precise definition of the classes is given in each particular regulation.
A flash point value may indicate the presence of highly volatile material(s) in a relatively non-volatile or non-flammable material and flash point testing can be a preliminary step to other investigations into the composition of unknown materials.
It is not appropriate for flash point determinations to be carried out on potentially unstable, decomposable, or explosive materials, unless it has been previously established that heating the specified quantity of such materials in contact with the metallic components of the flash point apparatus, within the temperature range required in this standard, does not induce decomposition, explosion or other adverse effects.
Flash point values are not a constant physical-chemical property of materials tested. They are a function of the apparatus design, the condition of the apparatus used, and the operational procedure carried out. Flash point can therefore be defined only in terms of this test method, and no general valid correlation can be guaranteed between results obtained by different test methods or with test apparatus different from that specified.
Determination of flash point - Pensky-Martens closed cup method
Warning: Persons using this standard shall be familiar with normal laboratory practice. The use of this standard may involve hazardous materials, operations and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of users of this standard to take appropriate measures to ensure the safety and health of personnel, and fulfill statutory and regulatory requirements for this purpose.
1 Scope
This standard describes three procedures of using the Pensky-Martens closed cup tester for determining the flash point of combustible liquids, liquids with suspended solids, liquids that tend to form a surface film under the test conditions.
Note 1: Although, kerosene with a flash point above 40℃ may be tested using this standard, it is standard practice to test the flash point of kerosene according to GB/T 21789. New lubricating oils are normally tested according to GB/T 3536.
Note 2: This standard may also be applicable to jet fuels with flash point below 40℃, but this precision has not been verified.
Warning: For certain mixtures no flash point, as defined, is observed; instead a significant enlargement of the test flame (not halo effect) and a change in colour of the test flame from blue to yellowish-brown can occur. Continued heating can result in significant burning of vapours around the test cup.
This standard is applicable to samples with flash point in the temperature range of 40℃ to 370℃. This standard describes three procedures, A, B and C. Procedure A is applicable to distillate fuels (diesel, biodiesel blends, heating oil and turbine fuels), new lubricating oils, paints and varnishes, and other homogeneous liquids not included in the scope of Procedures B or C. Procedure B is applicable to residual fuel oils, cutback asphalt, used lubricating oils, liquids that tend to form a surface film under test conditions or are of such kinematic viscosity that they are not uniformly heated under the stirring and heating conditions of Procedure A. Procedure C is applicable to determination of BD100 biodiesel samples. This standard is not applicable to water-borne paints and varnishes.
Note 3: When monitoring the lubricating oil system, in order to compare the flash point of new lubricating oil and used lubricating oil, Procedure A may also be used to determine the flash point of used lubricating oil, but this precision is only applicable to Procedure B.
Note 4: Water-borne paints and varnishes may be tested using GB/T 5208. Liquids containing traces of highly volatile materials may be tested using GB/T 21775 or GB/T 5208.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 3186 Paints, varnishes and raw materials for paints and varnishes - Sampling (GB/T 3186-2006, ISO 15528: 2000, IDT)
GB/T 4756 Method for manual sampling of petroleum liquids (GB/T 4756-2015, ISO 3170: 2004, MOD)
GB/T 20777 Paints and varnishes - Examination and preparation of test samples (GB/T 20777-2006, ISO 1513: 1992, IDT)
GB/T 27867 Petroleum liquids - Automatic pipeline sampling (GB/T 27867-2011, ISO 3171: 1998, IDT)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
flash point
lowest temperature of the oil, at which application of an ignition source causes the vapour of the oil to ignite and flame
4 Method summary
The test portion is placed into the test cup and heated to give a constant temperature increase with continuous stirring at specified speed. An ignition source is directed through an opening in the test cup lid at regular temperature intervals with simultaneous interruption of stirring. The lowest temperature at which the application of the ignition source causes the vapour of the test portion to ignite and a flame propagate over the surface of the liquid is recorded as the flash point at the absolute barometric pressure. This temperature is corrected to standard atmospheric pressure using a specified equation.
5 Reagents and materials
5.1 Cleaning solvent, for removal of traces of sample from the test cup and cover. The choice of solvent will depend upon the previous material tested and the tenacity of the residue. Low volatility aromatic (benzene free) solvents may be used to remove traces of oil, and mixed solvents such as toluene-acetone-methanol may be efficacious for the removal of gum-type deposits.
5.2 Standard samples: see Annex B.
Foreword i
Introduction iv
1 Scope
2 Normative references
3 Terms and definitions
4 Method summary
5 Reagents and materials
6 Apparatus
7 Apparatus preparation
8 Sampling
9 Sample handling
10 Procedure
11 Calculation
12 Expression of results
13 Precision
14 Test report
Annex A (Informative) Structure difference comparison between this standard and ISO 2719:
Annex B (Informative) Apparatus verification
Annex C (Normative) Pensky-Martens closed cup test apparatus
Annex D (Normative) Temperature measuring device specification
Bibliography
