Approved Test Procedures -
AT# G1000/August 1998
Gloves
1. Purpose
1.1 The purpose of this test procedure is to determine
the electrical resistance and relative static charging propensity
of gloves used for ESD control applications.
1.2 It is not the purpose of this test procedure
to set standards of acceptance.
2. Scope
This test procedure is intended for use with gloves
of all construction and materials.
3. Principle
3.1 The beneficial contribution of electrical
conductivity to the dissipation of static charges generated by
persons using gloves in ESD control work functions has long been
recognized. Gloves with reasonable conductivity across the surface
and to the hand help keep static charges to a minimum. However,
conductivity is not sufficient to characterize the ESD performance
of a glove for work with all products and materials.
3.2 When gloves have a reasonable conductivity
they typically will keep to a minimum the static charges on conductive
materials which are being handled. When insulative materials such
as plastic IC packages and fiberglass substrates are handled,
many gloves - even though conductive - impart high static charges
through triboelectric effects.
3.3 This test procedure characterizes gloves for
their electrostatic effects on most products.
4. Safety Precautions
4.1 Note: these safety precautions are for information
purposes only. The precautions are ancillary to the testing procedures
and are not intended to be all inclusive. It is the users responsibility
to use safe and proper techniques in handling materials in this
test method. Manufacturers MUST be consulted for specific details
such as material safety data sheets and other manufacturers recommendations.
All OSHA standards and rules must also be consulted and followed.
4.2 Where electrical instrumentation is required,
all manufacturers' recommendations for safety must be adhered
to as well as all applicable electrical codes of practice. If
test personnel are not familiar with safety precautions, a competent
electrical technician or electrician must be consulted.
5. Apparatus and Materials
5.1 Test area: Standard test conditions
for this test method require a room or large enclosure which can
be maintained at 22 +/- 2 C and at a relative humidity of 12 +/-
3 % and suitable means for monitoring these conditions. Special
requirements of end use may dictate the use of other testing conditions.
Audit measurements shall be at the recorded ambient conditions
during the tests.
5.2 Ohmmeter: Electrical resistance measurement
instrumentation capable of reading the expected range of resistances.
Typically this range for static protective gloves should be between
10 kilo Ohms and 100 Gig Ohms. The electrical resistance measuring
instrument should have a regulated output voltage capability of
ten (10) to 100 volts. Ten (10) volts should be used for more
conductive gloves and 100 volts for the more resistive gloves.
5.3 Resistance Electrodes: Two cylindrical
2.3 kg metal electrodes with a diameter of 63.5 mm each having
contacts of electrically conductive elastomeric material with
a thickness of approximately 6.35 mm and Shore-A (IRHD) durometer
hardness of approximately 50. The resistance between the two electrodes
should be less than 100 k Ohms when measured at 10 volts on a
conductive metal surface. Standard electrodes constructed in accordance
with NFPA 99 and ASTM F-150 may be modified to achieve these characteristics.
A surface that has a point-to-point resistance of greater than
1.0 Tera Ohms shall be used as the specimen support surface for
all resistance measurements except those involving the human hand.
5.4 Charged Plate Monitor: The charged
plate monitor shall have an aluminum plate approximately 7 cm
by 12 cm with a total capacitance of approximately 15 picofarads.
The charged plate monitor shall be capable of measuring 2,000
volts, +/- 10%.
5.5 Faraday Cup & Coulomb Meter: The
Coulomb meter shall be capable of measuring 200 nano Coulombs,
+/- 10%. The Faraday cup shall be able to receive the specimen
under test inside the cup with a minimum of 25 mm distance to
the top of the cup.
5.6 Triboelectric Test Material: For this
procedure the material chosen to represent the tribocharging propensity
for gloves is a 26 mm X 26 mm BGA (ball grid array) IC which is
composed of an epoxy IC package on a fiberglass and metal contact
substrate. Special requirements may dictate the use of other materials.
5.7 Wrist Strap: A standard fabric style
wrist strap connected directly to the resistance measurement instrument.
5.8 Air Ionizer: A forced air high voltage
ionizer with an imbalance of less than +/- 1 volt.
6. Test Specimens
A minimum of 6 glove samples should be tested
after being chosen by a valid sampling procedure.
7. Conditioning of Specimens
7.1 All test gloves shall be preconditioned at
22 +/- 2 C and at a relative humidity of 12 +/- 3% for a period
of at least 48 hours.
7.2 Gloves being audited while in use may tested
at ambient conditions.
8. Test Procedures
8.1 Resistance - Palm to Fingers
8.1a Place the glove under test on the insulative
support. Position one electrode on the inside palm portion of
the glove and the other electrode on the thumb of the glove.
8.1b Record the resistance reading.
8.1c Leaving the first electrode on the palm of
the glove reposition the second electrode on each finger of the
glove separately. Record the resistance readings of each finger.
8.1d Repeat the above procedure for all six glove
specimens.
8.2 Resistance - Finger to Body
8.2a This test procedure shall be measured at
10 volts.
8.2b Place the glove under test on the technician's
hand of preference. Attach the ungrounded wrist strap to the wrist
of the gloved hand. Attach a wrist strap lead to the resistance
meter. Make sure the wrist strap makes a good connection with
the skin. Lotions may be used to assure good connection. Do not
contaminate the glove with the wrist lotion.
8.2c Attach one electrode to the other terminal
of the resistance meter. Press the index finger of the gloved
hand against the conductive rubber of the electrode.
8.2d Record the resistance reading between the
electrode being touched by the gloved hand and the wrist.
8.2e Repeat the above procedure for all five fingers.
8.2e Repeat the above procedure for all six glove
specimens.
8.3 Resistance - Palm to Body
8.3a This test procedure shall be measured at
10 volts.
8.3b Place the glove under test on the technician's
hand of preference. Attach the ungrounded wrist strap to the wrist
of the gloved hand. Attach a wrist strap lead to the resistance
meter. Make sure the wrist strap makes a good connection with
the skin. Lotions may be used to assure good connection. Do not
contaminate the glove with the wrist lotion
8.3c Attach one electrode to the other terminal
of the resistance meter. Pick up and grasp the electrode with
the gloved hand.
8.3d Record the resistance reading between the
electrode being grasped by the gloved hand and the wrist.
8.3e Repeat the above procedure for all six glove
specimens.
8.4 Triboelectric Charge Generation - Charged
Plate
8.4a Place the glove under test on the technician's
hand of preference. Attach the grounded wrist strap to the wrist
of the gloved hand. Make sure the wrist strap makes a good connection
with the skin. Lotions may be used to assure good connection.
Do not contaminate the glove with the wrist lotion.
8.4b With the gloved hand stroke the aluminum
plate vigorously five (5) times without lifting the gloved hand
and as the last stroke is complete, extremely quickly remove the
gloved hand from the aluminum plate.
8.4c Record the voltage readings.
8.4d Repeat the above procedure for all six glove
specimens.
8.5 Triboelectric Charge Generation - Faraday
Cup
8.5a Place the glove under test on the technician's
hand of preference. Attach the grounded wrist strap to the wrist
of the gloved hand. Make sure the wrist strap makes a good connection
with the skin. Lotions may be used to assure good connection.
Do not contaminate the glove with the wrist lotion.
8.5b Clean the BGA triboelectric sample with Isopropyl
alcohol. Dry the BGA sample and gloved hand under the air stream
of the air ionizer. Zero the Faraday cup.
8.5c With the gloved hand hold the BGA sample
between the thumb and forefinger. Rub the BGA sample five (5)
times with the thumb and forefinger and as the last rub is complete,
quickly drop the BGA sample into the Faraday cup.
8.5d Record the Coulomb readings.
8.5e Repeat the above procedures for all six glove
specimens. Neutralize the BGA sample and gloved hand under the
air stream of the ionizer between each test.
9. Audit Test Procedures
The above tests may be performed on gloves in
use in the field under the ambient conditions of the work areas.
The results may of course be only used as a comparison since the
ambient conditions may be favorable or not to any particular style
of glove.
10. Report of Data
- Report all readings .
- Report the average of all sets of readings.
- Report the date, time, humidity and temperature
of the tests.
