ISO 21171:2006

INTERNATIONAL ISO
STANDARD 21171
First edition
2006-05-01
Medical gloves — Determination
of removable surface powder
Gants à usage médical — Détermination de la poudre de surface
amovible
Reference number
©
ISO 2006
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©  ISO 2006
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ii © ISO 2006 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Principle. 1
3 Terms and definitions. 1
4 Apparatus. 2
5 Reagents. 2
6 Sampling. 2
7 Method A — Procedure for powdered gloves. 2
8 Calculation of the result (method A). 3
9 Methods B and C — Procedure for “powder-free” gloves . 3
10 Precision. 6
11 Test report. 8
Bibliography . 9

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 21171 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee
SC 3, Raw materials (including latex) for use in the rubber industry.
This International Standard is based on ASTM D 6124-01, Standard Test Method for Residual Powder on
Medical Gloves, copyright ASTM, used with permission of ASTM.
For the purposes of this International Standard, the CEN annex regarding fulfilment of European Council
Directives has been removed.
iv © ISO 2006 – All rights reserved

Introduction
Depending on their method of manufacture, some medical gloves can have on their surface a small amount of
powder, normally modified corn-starch, which is intended to assist donning. Current thinking is that the
presence of excessive amounts of such powder can present a health hazard. The methods for the
determination of removable surface powder in this International Standard are based on those given in
ASTM D 6124-01, from which they differ in the method for determining removable powder from powder-free
surgeon's gloves and in the precision data.

INTERNATIONAL STANDARD ISO 21171:2006(E)

Medical gloves — Determination of removable surface powder
WARNING — Persons using this International Standard should be familiar with normal laboratory
practice. This standard does not purport to address all of the safety problems, if any, associated with
its use. It is the responsibility of the user to establish appropriate safety and health practices and to
ensure compliance with any national regulatory conditions.
1 Scope
This International Standard specifies methods for the determination of readily removable powder on the
surface of gloves for medical use. Three methods are specified: method A for powdered gloves and
methods B and C for powder-free gloves. This International Standard does not address safety issues that may
be associated with the presence of powder on gloves nor does it prescribe limits on the amounts that may be
present. The applicability of this International Standard to medical gloves not made from rubber has not been
established.
2 Principle
The surfaces of a glove are washed with water to remove the water-insoluble powder which is then
determined by filtration followed by weighing. The number of gloves used for the procedure depends on
whether the gloves are nominally powder-free or powdered.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
powder
all water-insoluble material on the surface of a glove that is removed by washing under the conditions of the
test
3.2
powdered gloves
gloves for which a powder has been used as a part of the manufacturing process, generally to facilitate
donning, and described by the manufacturer as “powdered”
3.3
powder-free gloves
gloves which are described by the manufacturer as “powder-free”
NOTE Gloves should always be clearly labelled as to whether they are powdered or powder-free (unlabelled gloves
would normally be unacceptable to consumers). Nevertheless, if a sample of gloves does not carry the designation
“powdered” or “powder-free”, the gloves should be analysed as if they were powdered.
4 Apparatus
Normal laboratory glassware and tweezers, together with the following:
4.1 Balance, accurate to 0,1 mg.
4.2 Mechanical shaker, capable of a minimum oscillation frequency of 1,7 Hz (102 cycles/min).
4.3 Drying oven, capable of maintaining 100 °C ± 5 °C.
4.4 Filters, 90 mm and 47 mm glass microfibre filters of 2,7 µm pore size, together with suction filtration
apparatus.
4.5 Desiccator.
5 Reagents
5.1 Wherever water is called for, distilled or deionized water shall be used.
6 Sampling
Randomly select an appropriate number of gloves from each lot to be evaluated. For determinations on
powdered gloves, use two gloves and for determinations on powder-free gloves use five gloves except in the
case of surgeon's gloves for which use three pairs (i.e. six gloves).
7 Method A — Procedure for powdered gloves
7.1 Before use, rinse all glassware and tweezers with water.
7.2 The test shall be carried out at 25 °C ± 5 °C on two gloves randomly selected.
7.3 Take a 90 mm, 2,7 µm pore size filter and place it in the desiccator for not less than 30 min. Remove
the filter and immediately weigh it on the balance, determining the mass to the nearest 0,1 mg. Record the
mass in grams (m ).
NOTE The use of a PTFE (polytetrafluoroethylene) base is suggested if experience shows that there is a risk of
tearing the filter on removal from a glass surface.
7.4 Place the filter in the suction apparatus.
7.5 Carefully remove a glove from its packaging and insert it into a 1 l capacity conical flask, or other
suitable container, containing 500 cm of water so that 1 cm to 3 cm of the cuff projects out round the rim of
the flask. Pour approximately 250 cm of water into the glove while holding a small portion of the cuff away
from the rim of the flask to allow air to be vented from the flask. While pouring the water into the glove ensure
that the projecting part of the cuff is rinsed. Tightly seal the flask with a rubber stopper covered by a small
piece of polypropylene sheet so that the flask does not leak. Place the sealed flask in the mechanical shaker
and oscillate for 30 s at a speed of not less than 1,7 Hz. Ensure that all the surfaces of the glove are well
washed.
7.6 Take the flask from the shaker and remove the stopper. Pour the water from inside the glove through
the filter in the suction filtration unit. Remove the glove from the flask and pour any remaining water from
inside the glove through the filter, followed by the water in the flask.
7.7 Using the same glove repeat the procedure of 7.5 and 7.6 with a further 500 cm of fresh water in the
flask and 250 cm in the glove.
2 © ISO 2006 – All rights reserved

7.8 Repeat the procedure of 7.7 twice more, to make a total of four fresh water rinses for a single glove.
Finally, rinse the flask and stopper covering with fresh water, to ensure that all material on them has been
transferred to the filter.
7.9 Using a second glove repeat the procedure of 7.5 to 7.8 (in the case of surgeon's gloves, use the other
one of the pair).
7.10 Remove as much water from the filter as possible by suction. Discard the filtrate. Carefully remove the
filter and transfer it to a washed and dried watch glass or Petri dish. Dry in an oven at 100 °C ± 5 °C for 1 h
then transfer to the desiccator to cool for not less than 30 min. Weigh the filter immediately after removal from
the desiccator to minimize re-adsorption of moisture. Record the mass, in grams, to the nearest 0,1 mg (m ).
8 Calculation of the result (method A)
The mass of powder, in milligrams, on the two gloves is given by
(m – m ) × 1 000
1 0
The average mass (m ) of powder per glove, in milligrams, is given by
A
mm−
m=×1 000
A
9 Methods B and C — Procedure for “powder-free” gloves
9.1 General
The procedure to be used for “powder-free” gloves is generally similar to that described above (see Clause 7).
However, it employs a smaller filter and five gloves, except in the case of surgeon's gloves when six are used
(see the Note) and the same water is used for rinsing each of them. Because only a small amount of powder
should be present, it is also necessary to run a blank.
NOTE Surgeon's gloves are packaged in pairs. As the right hand and the left hand are not normally produced at the
same time, it is important to test the same number of each hand.
9.2 Method B — Procedure for “powder-free” gloves other than surgeon's gloves
9.2.1 Before use, rinse all glassware and tweezers with water.
9.2.2 The test shall be carried out at 25 °C ± 5 °C on five gloves randomly selected.
9.2.3 Take a 47 mm, 2,7 µm pore size filter. Transfer it to the suction apparatus, rinse it with three portions
of 50 cm of water and suck free of water. Place the filter on a watch glass or Petri dish and dry it in an oven
at 100 °C ± 5 °C for 1 h. Transfer the filter to a desiccator to cool for at least 30 min before use. Remove the
filter and immediately weigh it on the balance, determining the mass to the nearest 0,1 mg. Record the mass
in grams (m ).
NOTE The use of a PTFE (polytetrafluoroethylene) base is suggested if experience shows that there is a risk of
tearing the filter on removal from a glass surface.
9.2.4 Place the filter in the suction apparatus.
9.2.5 Carefully remove a glove from its packaging and insert it into a 1 l capacity conical flask, or other
suitable container, containing 500 cm of water so that 1 cm to 3 cm of the glove projects out round the rim of
the flask. Pour approximately 250 cm of water into the glove while holding a small portion of the cuff away
from the rim of the flask to allow air to be vented from the flask. While pouring the water into the glove, make
sure that the projecting part of the cuff is rinsed. Tightly seal the flask with a rubber stopper covered by a small
piece of polypropylene sheet so that the flask does n
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