Standards related to:

GB/T 18146.2-2015**GB/T 18146.2-2015: PDF in English (GBT 18146.2-2015) **

GB/T 18146.2-2015

GB

NATIONAL STANDARD OF THE

PEOPLE’S REPUBLIC OF CHINA

ICS 59.060.10

B 32

Replacing GB/T 18146.2-2000

Hemp fiber - Part 2: Raw white hemp sliver

ISSUED ON: JULY 03, 2015

IMPLEMENTED ON: OCTOBER 01, 2015

Issued by: General Administration of Quality Supervision, Inspection and

Quarantine of the People's Republic of China;

Standardization Administration of the People's Republic of China.

Table of Contents

Foreword ... 3

1 Scope ... 4

2 Normative references ... 4

3 Technical requirements ... 4

4 Sampling quantity and sampling method ... 5

5 Test methods ... 6

6 Quality assessment ... 9

7 Handover acceptance ... 9

8 Packaging, marking, transportation and storage ... 10

Hemp fiber - Part 2: Raw white hemp sliver

1 Scope

This Part of GB/T 18146 specifies technical requirements, sampling quantity and

sampling method, test method, quality assessment, inspection rules, packaging,

marking, transportation and storage for raw white hemp sliver.

This Part is applicable to quality assessment of raw white hemp sliver.

2 Normative references

The following referenced documents are indispensable for the application 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 8170, Rules of rounding off for numerical values and expression and

judgement of limiting values

GB/T 9995, Determination of moisture content and moisture regain of textile - Oven-

drying method

GB/T 18147.1, Test method for hemp fibre - Part 1: Test method for oil content of

hemp fibre

GB/T 18147.3, Test method for hemp fiber - Part 3: Test method for length of hemp

fiber

GB/T 18147.4, Test method for hemp fiber - Part 4: Test method for fineness of hemp

fiber

GB/T 18147.5, Test method for hemp fiber - Part 5: Test method for breaking

strength of hemp fiber

GB/T 18147.6, Test method for hemp fiber - Part 6: Test method for defect in hemp

fiber

3 Technical requirements

3.1 The raw white hemp sliver is divided into first, second and third categories

according to the fineness. Each category is divided into first class and second class. The

products lower than the second class are substandard.

4.2.1.1 Sampling for moisture regain test: Randomly draw a hemp ball from each piece.

Each hemp ball is sampled about 50g (half shall be taken from the core and the outer

layer of the hemp ball). Immediately pack into an airtight container for moisture regain

testing.

4.2.1.2 Sampling for appearance quality inspection: Take 2 hemp silvers from each

hemp ball in each piece. Each silver is 3m. There are 10 silvers in total, for appearance

quality inspection.

4.2.1.3 Sampling for quality coefficient of variation inspection per meter: From the

samples after appearance quality inspection, extract 2 from each piece. Each one is 1m.

There are 20 in total. Measure the coefficient of variation of the mass per meter.

4.2.1.4 In the specimens for which the coefficient of variation of mass per meter has

been measured, randomly extract 3 hemp slivers to form a laboratory sample for test

sampling:

a) Sampling for oil content test: Take 1 specimen from each hemp sliver. Each is

about 5g. Measure the oil content.

b) Sampling for length test: Take 1 specimen from each hemp sliver. Each is about

500mg. Measure the fiber length.

c) Sampling for fineness test: Take 1 specimen from each hemp sliver. Each is about

300mg. Measure the fineness.

d) Sampling for breaking strength test: Take 4 specimens from each hemp sliver.

Each is about 8mg. Measure the breaking strength.

e) Sampling for hemp grain and hard strip rate test: Take 1 specimen from each hemp

sliver. Each is about 1g. Measure the hemp grain and hard strip rate.

4.2.2 Batch sampling

For multiple batch samples, each batch shall be sampled and tested according to the

provisions of 4.2.1. The arithmetic mean of the test data is the test result of the batch.

5 Test methods

5.1 Moisture regain

Through hand touching and visual inspection, it is confirmed that the moisture regain

of hemp fiber in the hemp piece has no obvious abnormality. Carry out according to

GB/T 9995.

5.2 Appearance quality

5.3.2.4 Calculate the coefficient of variation of mass per meter according to formula

(3). The result is rounded to one decimal place.

Where,

CV - The coefficient of variation of mass per meter;

S - Standard deviation of mass per meter, in grams (g);

m - The average mass of the specimen per meter, in grams (g).

5.3.2.5 The numerical rounding of the calculation results is carried out according to

GB/T 8170.

5.4 Oil content

According to GB/T 18147.1.

5.5 Average length, short fiber rate

According to GB/T 18147.3.

5.6 Fineness

According to GB/T 18147.4.

5.7 Breaking strength

According to GB/T 18147.5.

5.8 Hemp grain and hard strip rate

According to GB/T 18147.6.

5.9 Official mass

5.9.1 The official mass inspection is based on batches. Weigh each batch. Record the

gross weight.

5.9.2 According to the batch size, according to the sampling quantity specified in 4.1,

weigh the mass of the package. Calculate the average mass of a single package. The

result is rounded to two decimal places.

5.9.3 Calculate the net weight of each batch of hemp fibers according to formula (4).

The result is rounded to three decimal places.

......

Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.