GB/T 16984-2008 English PDF (GBT16984-2008)

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GB/T 16984-2008: Raw hemp
GB/T 16984-2008
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 59.060.10
W 30
Replacing GB/T 16984-1997
Raw Hemp
ISSUED ON: AUGUST 7, 2008
IMPLEMENTED ON: DECEMBER 1, 2008
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative References ... 4 
3 Terms and Definitions ... 4 
4 Technical Requirements ... 5 
5 Instruments and Tools ... 7 
6 Sampling ... 7 
7 Standard Atmospheres for Pre-conditioning, Conditioning and Testing ... 8 
8 Inspection Procedures ... 8 
9 Grading ... 9 
10 Calculation of Conditioned Weight ... 9 
11 Packaging, Marking, Transportation and Storage ... 10 
Raw Hemp
1 Scope
This Standard specifies the technical requirements, test methods, inspection rules,
packaging, marking, transportation and storage of raw hemp.
This Standard is applicable to hemp bast that has received the processing of peeling,
including water retted hemp, sunned hemp and peeling hemp from green straw, etc.
2 Normative References
Through the reference in this Standard, the clauses of the following documents
become clauses of this Standard. In terms of references with a specified date, all the
subsequent modification sheets (excluding the corrected content) or revised versions
are not applicable to this Standard. However, the various parties that reach an
agreement in accordance with this Standard are encouraged to explore the possibility
of adopting the latest version of these documents. In terms of references without a
specified date, the latest version is applicable to this Standard.
GB 6529 Textiles - Standard Atmospheres for Conditioning and Testing
GB/T 8170 Rules of Rounding off for Numerical Values and Expression and Judgement
of Limiting Values
GB/T 12411 Test Methods for Jute and Kenaf Fibers
GB/T 12945 Jute Fiber
3 Terms and Definitions
The following terms and definitions are applicable to this Standard.
3.1 Hemp
Hemp belongs to the Cannabaceae and Cannabis. It is a collective term for industrial
hemp1 plant, hemp bast and hemp fiber.
3.2 Raw Hemp
Raw hemp refers to industrial hemp bast used as the raw material of textiles, including
water retted hemp, sunned hemp and peeling hemp from green straw, etc.
1 Industrial hemp refers to low-toxic (the content of THC is below 0.3%) and non-toxic (the content of
THC is below 0.1%) hemp.
3.3 Water Retted Hemp
Water retted hemp refers to hemp bast obtained from industrial hemp stems through
retting, washing, peeling and drying.
3.4 Sunned Hemp
Sunned hemp refers to hemp bast obtained from industrial hemp stems through drying
in the air, stacking and exposure to the sun before peeling.
3.5 Peeling Hemp from Green Straw
Peeling hemp from green straw refers to hemp bast obtained from industrial hemp
directly peeled after harvesting.
3.6 Speck
Speck refers to a defect of raw hemp of industrial hemp as a result of pests, wind
damage and mildew that would affect the use of textiles.
3.7 Trash
Trash refers to hemp leaves, hemp chips, hemp roots and bast with no processing
value, and other mixed substances in raw hemp of industrial hemp.
4 Technical Requirements
4.1 Rules of Grading
4.1.1 Raw hemp is classified into Grade-1, Grade-2 and Grade-3, and those that fail
to reach Grade-3 are considered to be inferior to grading.
4.1.2 Raw hemp takes sensory characteristics, bundle fiber specific breaking tenacity
and effective length as the grading conditions, and the lowest one among them shall
be used to determine the grade. The rules of grading of raw hemp are: see Table 1 for
water retted hemp; see Table 2 for sunned hemp; see Table 3 for peeling hemp from
green straw.
4.2 Moisture Regain Rate
The conventional moisture regain rate of raw hemp is 12%; the actual moisture regain
rate shall be not greater than 15%. When the actually measured moisture regain rate
of a batch of hemp exceeds 15%, it shall be dried before being delivered for sales.
4.3 Impurity Rate
4.3.1 The conventional impurity rate of raw hemp is 3%.
4.3.2 In terms of water retted hemp, the impurity rate shall be not greater than 3% for
Grade-1, not greater than 4% for Grade-2 and not greater than 5% for Grade-3.
4.3.3 In terms of sunned hemp, the impurity rate shall be not greater than 3% for all
grades.
4.3.4 In terms of peeling hemp from green straw, the impurity rate shall be not greater
than 3% for Grade-1, not greater than 4% for Grade-2 and not greater than 5% for
Grade-3.
4.3.5 When the impurity rate of raw hemp is excessively high, impurities shall be
removed first, and delivered for sales after satisfying the requirements.
5 Instruments and Tools
5.1 Balance: measuring range of 100 g, division value of 1 mg; platform balance:
measuring range of 5 kg, division value of 0.1 g; weighing scale: measuring range of
100 kg, division value of 0.1 kg.
5.2 Oven: temperature control range of 50 °C ~ 150 °C, temperature control accuracy
of 1 °C; attached balance: measuring range of 100 g, division value of 10 mg.
5.3 Bundle fiber strength tester: effective distance of sample-clamping is 200 mm;
tensile speed is 200 mm/min; measuring range is not less than 900 N; division value
is not greater than 1 N.
5.4 Steel tape: measuring range of 3 m, division value of 1 mm.
5.5 Steel ruler: measuring range of 300 mm, division value of 0.5 mm.
6 Sampling
6.1 The inspection and sampling of raw hemp shall be conducted in accordance with
the methods specified in GB/T 12411. From each batch of raw hemp, randomly select
6 samples; each sample shall be not less than 3 kg. Three of them shall be used for
the inspection of sensory characteristics, and the remaining three of them shall be used
Pi---average tensile breaking strength of the test specimen, expressed in (N);
Pt---average bundle fiber specific breaking tenacity, expressed in (cN/dtex);
k---unit conversion factor; the value is 0.003.
The calculation result shall be rounded off to two decimal places in accordance with
the stipulations of GB/T 8170.
8.4 Inspection of Hemp Bundle Effective Length
Measure from the base to the tip of the hemp bundle. Take the length of 80% of the
total number of hemps as the effective length of hemp bundle.
8.5 Inspection of Impurity Rate
Conduct the inspection in accordance with the methods specified in GB/T 12411.
9 Grading
In accordance with the inspection results of sensory characteristics, hemp bundle
specific breaking tenacity and hemp bundle effective length, and the stipulations of 4.1,
determine the grading.
10 Calculation of Conditioned Weight
Conditioned weight shall be calculated in accordance with Formula (2):
Where,
G---conditioned weight, expressed in (kg);
G0---actually measured weight, expressed in (kg);
Wk---conventional moisture regain rate, 12%;
W---actually measured moisture regain rate, expressed in (%);
Fk---conventional impurity rate, 3%;
F---actually measured impurity rate, expressed in (%).
The calculation result shall be rounded off to one decimal place in accordance with the
stipulations of GB/T 8170.