Skip to product information
1 of 9

PayPal, credit cards. Download editable-PDF & invoice in 1 second!

GB/T 6678-2003 English PDF (GBT6678-2003)

GB/T 6678-2003 English PDF (GBT6678-2003)

Regular price $135.00 USD
Regular price Sale price $135.00 USD
Sale Sold out
Shipping calculated at checkout.
Delivery: 3 seconds. Download true-PDF + Invoice.
Get QUOTATION in 1-minute: Click GB/T 6678-2003
Historical versions: GB/T 6678-2003
Preview True-PDF (Reload/Scroll if blank)

GB/T 6678-2003: General principles for sampling chemical products
GB/T 6678-2003
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.100.01
G 04
Replacing GB/T 6678-1986
General Principles for Sampling Chemical Products
ISSUED ON: OCTOBER 11, 2003
IMPLEMENTED ON: MAY 01, 2004
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 4
4 Purposes of Sampling ... 4
5 Basic Principle of Sampling ... 6
6 Sampling Plan ... 6
7 Sampling Technology ... 7
8 Sampling Safety ... 11
9 Sampling Records and Sampling Report ... 11
10 Sample Container and Storage ... 12
11 Measuring One-Time Sampling Inspection ... 12
Appendix A (Informative) Relevant Examples of this Standard ... 19
Appendix B (Normative) Relevant Schedules of this Standard ... 24
General Principles for Sampling Chemical Products
1 Scope
This Standard specifies the terms and definitions of chemical product sampling, sampling
purposes, basic principles of sampling, sampling plans, sampling techniques, sampling safety,
sampling records and sampling reports, sample containers and storage, and metering one-time
sampling inspection.
This Standard applies to the sampling of chemical products.
2 Normative References
The provisions in following documents become the provisions of this Standard through
reference in this Standard. For dated references, the subsequent amendments (excluding
corrigendum) or revisions do not apply to this Standard; however, parties who reach an
agreement based on this Standard are encouraged to study if the latest versions of these
documents are applicable. For undated references, the latest edition of the referenced document
applies.
GB/T 3723 Sampling of Chemical Products for Industrial Use - Safety in Sampling (GB/T
3723-1999, idt ISO 3165:1976)
GB/T 4650 Chemical Products for Industrial Use – Sampling – Vocabulary (GB/T 4650-
1998, idt ISO 6206:1979)
GB/T 6679 General Rules for Sampling Solid Chemical Products
GB/T 6680 General Rules for Sampling Liquid Chemical Products
GB/T 6681 General Rules for Sampling Gaseous Chemical Products
3 Terms and Definitions
For the purposes of this Standard, the terms and definitions given in GB/T 4650 apply.
4 Purposes of Sampling
The basic purpose of sampling is to obtain a representative sample from the overall material to
be tested, and to obtain data within the allowable error through the detection of the sample, so
4.4.3 To classify materials by hazard, etc.
5 Basic Principle of Sampling
The basic principle of sampling is to make the collected samples fully representative.
When the cost of sampling (such as material cost, operation cost, etc.) is high, the sampling
error and cost can be properly considered when designing the sampling plan, but the
requirements for sampling error shall be met.
6 Sampling Plan
6.1 Factors influencing the sampling plan
6.1.1 The nature, physical state and range of the overall material to be collected. The range can
be a certain delivery batch agreed by the purchaser and supplier, or a certain production batch
produced intermittently; and in the case of continuous production, it can be the material
produced within a certain time interval;
6.1.2 The possibility of contamination or deterioration of the overall material during or after
production;
6.1.3 Acceptable sampling error;
6.1.4 Specifications of inspected materials;
6.1.5 Characteristic definition of material judgment standard;
6.1.6 Precision of the detection method;
6.1.7 Value of the material;
6.1.8 Possibility to simplify sampling operations.
6.2 Basic content of sampling plan
6.2.1 Determine the range of the overall material;
6.2.2 Determine the sampling unit and the secondary sampling unit;
6.2.3 Determine the number of samples, the quantity of samples and sampling location;
6.2.4 Specify sampling operation methods and sampling tools;
6.2.5 Specify the processing method of the sample;
The variability of the overall material characteristic values and their types are the basis for
designing a sampling plan. They exist objectively, but it is expensive and difficult to operate to
estimate them through the detected data. Therefore, the actual measurement is generally not
carried out when designing the sampling plan, but inferences and assumptions are made based
on experience and the material information that has been mastered.
7.4 Sampling of uniform material
7.4.1 The uniformity of uniform materials may vary with the size of the specified unit to be
investigated. For example, 10 t of material packed in 50 kg barrels has no significant difference
in the average value of characteristics between barrels. Therefore, this batch of materials are
uniform materials for the barrel unit. If the materials in the barrel are segregated during
processing, there will be differences in the average characteristic values between 500 g portions
of materials taken from different parts of the barrel. Therefore, for the 500 g material as the
inspection unit, the material is non-uniform.
7.4.2 Sampling of uniform materials can, in principle, be carried out at any part of the materials.
But beware:
7.4.2.1 Impurities shall not be brought into during the sampling process.
7.4.2.2 Avoid material changes (such as water absorption, oxidation, etc.) during the sampling
process.
7.5 Sampling of non-uniform materials
For the sampling of non-uniform materials, in addition to paying attention to the same two
points as uniform materials, random sampling is generally adopted. The obtained samples are
measured separately; and the results of all samples are aggregated to obtain an estimate of the
average and variability of the characteristics of the overall material. If several equal samples
(or unequal samples taken in proportion to the amount of represented material) are randomly
selected from the overall materials, combined into a large sample, and then reduced into the
final sample; then the estimate quantitative error of the average value of the characteristics
obtained from it is large, meanwhile, the information about the variability of the characteristic
value cannot be obtained.
Designing the sampling plan according to the variability types of the acquired characteristic
values can make the collected samples better represent the overall materials and save the cost.
7.5.1 Sampling of random non-uniform materials
A random non-uniform material refers to a material in which the average value of the
characteristics of any part of the overall material is independent of the average value of the
characteristics of the adjacent parts. The sampling can be randomly selected or non-randomly
selected.
7.5.2 Sampling of oriented non-random non-unform materials
Oriented non-random non-uniform materials refer to materials in which the characteristic
values of the overall material change along a certain direction. For example, when the solid
granular material is conveyed, the material that is separated vertically and horizontally due to
the difference in particle size and weight. Another example is that after filling at high
temperature, it gradually solidifies from the near wall to the center, and the materials that the
impurities content must form a gradient with the solidification sequence. Such materials shall
be sampled in layers, and samples that can represent the layer of materials shall be taken from
each layer with diff...
View full details