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IS0
INTERN AT1 ON A L O R GA N IZ AT1 O N FOR STAN DA RD ILATION
IS0 RECOMMENDATION
R 950
CEREALS
SAMPLING (AS GRAIN)
1st EDITION
January 1969
COPYRlGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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ISO/R 950-1969 (E)
IS0 Recommendation January 1969
R 950
CEREALS
SAMPLING (AS GRAIN)
INTRODUCTION
Correct sampling is an operation that requires most careful attention. Emphasis cannot therefore be
too strongly laid on the necessity of obtaining a properly representative sample of grain. Careless or
inaccurate sampling could lead to misunderstanding and unwarranted financial adjustments.
I
The procedures given in this IS0 Recommendation are recognized as good practice and it is strongly
recommended that they be followed whenever practicable. It is recognized that it is difficult to lay
down fixed rules to be followed in every case, and particular circumstances may render some modifi-
cation of the method desirable, for example if it is desired to check the uniformity of a consignment
by the examination of individual primary samples.
In certain areas there are widely recognized trade associations which prescribe rules for the sampling
procedures to be used in contracts under their auspices. In no case will this IS0 Recommendation
override the rules laid down in such contracts.
1. SCOPE
1.1 This IS0 Recommendation specifies general conditions relating to sampling for the assessment
of the quality of cereal grains.
1.2 Field of application
This IS0 Recommendation does not apply to seed grain.
2. DEFINITIONS
Terms used in this IS0 Recommendation have the following definitions
2.1 Consignment. The quantity of grain dispatched or received at one time and covered by a
particular contract or shipping document.
2.2 Lot. A stated portion of the consignment which will allow the quality to be assessed.
2.3 Primary sample. A small quantity of grain taken from a single position in the lot.
A series of primary samples should be drawn, from different positions in the lot, which when
bulked will be representative of the lot.
2.4
Bulk sample. The quantity of grain formed by combining and mixing the primary samples drawn
from any one particular lot.
2.5 Final lot sample (laboratory sample). A sample representing the quality of the lot, obtained by
reduction of the bulk sample and intended for analysis or other examination.
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ISO/R 950-1969 (E)
3. GENERAL
3.1 Samples should be drawn jointly by sampling superintendents appointed by buyers and sellers
or by a sampling superintendent appointed jointly.
3.2 Samples should be fully representative of the lots from which they are drawn. Therefore, as
the composition of the lot is seldom uniform, a sufficient number of primary samples should be
drawn and carefully mixed, thus giving a bulk sample from which are obtained, by successive
divisions, the final lot samples.
3.3 It is essential that grain which is sea-damaged or otherwise damaged in transit or out of con-
dition should be kept separate from the sound grain and sampled separately. Samples of the
unsound material should not be mixed with samples of the sound material.
3.4 Special care is necessary to ensure that all sampling apparatus is clean, dry and free from foreign
odours.
Sampling should be carried out in such a manner as to protect the samples, the sampling instru-
ments and the containers in which the samples are placed from adventitious contamination
such as rain, dust, etc.
4. APPARATUS
The apparatus required falls under the foliowing headings. Examples are given under each heading.
(See also Fig. 1 to 9 in Annex A.)
4.1 Sampling from bunt
Shovels, hand-scoops, cylindrical samplers and apparatus for drawing primary samples periodi-
cally from a flow of grain.
4.2 Sampling from bags
Sack-type spears or triers.
4.3 Mixing and dividing
Shovels and dividing apparatus.
5. LOCATION OF SAMPLING
The location and time of sampling should be determined by the agreements between the parties
concerned. Particular recommendations applying to loading and discharge are given below.
5.1 Loading
It is important that grain which is to be dispatched by vessel should be sampled during loading,
or immediately before, at the place of loading.
5.2 Discharge
Most grain is received from ocean-going vessels or river transport. In both cases, sampling should
be carried out during discharge from the vessel.
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ISO/R 950-1969 (E)
6. METHOD OF DRAWING SAMPLES FROM CEREALS CARRIED IN BULK
6.1 Carriage by sea or inland waterway
6.1.1 Unless otherwise specified in the contract, consignments should be considered in lots of
500 tonnes* or such part thereof as constitutes a single consignment or balance.
6.1.2 When sampling takes place while the product is in motion, primary samples should be
drawn at time intervals dependent on the rate of flow.
6.1.3 When bulk grain is sampled in the hold during discharge, primary samples should be drawn
from as many places as possible, excluding the run, and at intervals determined by the rate of
discharge.
6.1.4 If sampling takes place from weigh hoppers, primary samples should be drawn by means of
cylindrical samplers, shovels, or mechanical samplers in accordance with the practice of the
port.
6.1.5 The procedure for silos or warehouses is necessarily dependent on local conditions.
6.2
Carriage by rail or road
6.2.1 Unless otherwise specified in the contract, each laden wagon or lorry should be sampled.
6.2.2 If sampling takes place from laden wagons or lorries, the primary samples should be drawn
throughout the whole depth of the layer, by means of a cylindrical sampler and at the
following points :
Wagons or lorries up to 15 tonnes :
five sampling points (middle and
approximately 50 cm from sides).
Wagons from 15 to 30 tonnes :
I' . :I
eight sampling points.
.
. .
Wagons from 30 to 50 tonnes
.
. eleven sampling points.
6.2.3 If the type of wagon does not allow samples to be drawn in this manner, or by agreement
between buyer and seller, the method of sampling should be as described in clause 6.1.2.
*
Metric tonnes. It = 1000 kg.
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ISO/R 950-1969 (E)
7. METHOD OF DRAWING SAMPLES FROM CEREALS CARRIED IN BAGS
Unless otherwise specified in the contract or unless the practice at a port requires otherwise, primary
samples should be drawn from different parts of the bag (for example, top, middle and bottom) by
means of a sack-type spear from the following numbers of bags :
to be sampled
in consignment
Each bag
up to 10
10, drawn at random
IO to 100
Square root (approximately) of total number,
More than 100
drawn according to a suitable sampling scheme*
8. BULK SAMPLE
The bulk sample sliould be formed by bringing together the primary samples and mixing them well.
9. FINAL LOT SAMPLES
The bulk sample should be divided down to the required number of final lot samples by use of
apparatus mentioned in section 4. The number of final lot samples to be drawn for analysis and
arbitration should be specified in the contract or otherwise agreed between buyer and seller.
10. SIZE OF SAMPLES
The following siLes of samples are usually suitable:
Primary Final loi
sample I sample I sample
All grains I 1 kg 1 100kg 1 5 kg I
500 tonnes (max.)
Larger or smaller final lot samples may be required in some cases. according to the tests to be carried
out.
*
See, for example, Annex B.
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ISO/R 950-1969 (E)
II. PACKAGING AND LABELLING OF SAMPLES
I I. I Packaging of samples
11.1.1 The final lot samples should be packed in unglazed, unbleached, insewn, cotton bags of
very close texture.*
11.1.2 Samples for the determination of moisture, or for other tests in which it is important to
avoid the loss of volatile matter (for example, examination for evidence of chemical treat-
m
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