Template For ENG STDS
WORLDWIDE
ENGINEERING Test Procedure GMW3205
STANDARDS
Determining the Resistance to Odor Propagation
of Interior Materials
1 Introduction
Note: Nothing in this standard supercedes applicable laws and regulations.
Note: In the event of conflict between the English and domestic language, the English language shall take
precedence.
1.1 Purpose. This standard shall be used to determine the odor propagation of automotive interior materials
(e.g. fabric, coated fabrics (vinyls), carpets, padding, insulators, felts, plastic parts, interior paints etc.) when
subjected to elevated temperatures and high humidity.
1.3 Applicability. Automotive interior materials (e.g. fabric, coated fabrics (vinyls), carpets, padding, insulators,
felts plastic parts, interior paints, etc.).
1.3 Remarks. This standard is written to communize the determination of odor propagation within GM.
2 References
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Note: Only the latest approved standards are applicable unless otherwise specified.
2.1 External Standards/Specifications.
None
2.2 GM Standards/Specifications.
None
2.3 Additional References.
VDA 270
3 Resources
3.1 Facilities.
3.1.1 Calibration. The test facilities and equipment shall be in good working order and shall have a valid
calibration label.
3.1.2 Alternatives. Alternative test facilities and equipment may also be used. However, all measuring variables
as specified in this standard shall be determined correctly with respect to their physical definition.
3.1.3 Air circulating oven capable of maintaining the required temperature to within ± 2 °C.
3.2 Equipment.
3.2.1 One (1) test container is required for each coding plus a control container. The test container, lid and rack
shall not release or absorb any odorous volatiles. Do not use plastic containers or plastic lids. Only containers
and lids of metal or containers of glass shall be used. The recommended metal containers (paint style cans) are
≈ 1 l. The lids may be pressure sealed for each test. If all glass containers are used, the lid shall be sealed by
means of a plain ground joint. Sealing grease or sealing rings shall not be used. Use of tape to keep desiccators
lids from sliding off the desiccators during the oven exposure is recommended if necessary.
Any necessary support shelves or racks within the container shall be made of glass/glazed ceramics or stainless
steel. Make sure that if glazed ceramics are used, that the plates are fully covered but the glaze so that no odor
absorption will occur.
The test container including lid and possibly the insert shall be cleaned carefully prior to each test. It shall have
no individual smell.
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3.2.2 Suitable cutting tools for preparation of test specimens.
3.2.3 Distilled or deionized water.
3.3 Test Vehicle/Test Piece. The size of the test specimens shall be governed by the amount of the material
used in the vehicle, and shall be selected to give the approximate ratios of test specimen volume and test
container volume according to Table 1 for cut goods (e.g. textiles, plastic roll good, leather, etc.), for weighable
parts (e.g. speaker panels, instrument panel, door panel) use the formula in Table 2.
For parts that consist of more than one individual part (e.g. door panel) the test shall be performed individually
for each material.
Typical composite materials shall be evaluated as a composite.
Table 1: Coding for Cut Goods
Coding Test specimen volume : Test container volume Example of materials for test
1 1 : 20 Padding felts
2 1 : 50 Carpets, fabrics
3 1 : 100 Plastic films
4 1 : 500 Parts for paneling
5 1 : 1000 Small parts as speaker panels
6 1 : to specification to requirements
Table 2: Formulas for Weighable Parts
P T
4
< 500 g = ×P×V
1000 l
3 g
500 g < P < 1000 g = × P + 0.5 ×V
1000 l l
2 g
1000 g < P < 3000 g = × P + 1.5 × V
1000 l l
1 g
3000 g < P = × P + 4.5 × V
1000 l l
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P = Mass of the part in g
V = Volume of the test container in l
T = Mass of the test piece in g
The specific coding will be shown on the individual engineering drawings, material specifications etc. The coding
system is defined in paragraph 8.
Where test specimens are taken from large components, they shall be cut to a thickness of 20 mm max.
A test specimen may consist of several individual pieces.
Run a minimum of one test for each required coding.
3.3.1 To calculate the test specimen size according to Table 1, first define the test specimen area that will fit flat
on the support shelf or rack. Define the thickness of the material and calculate the volume in mm 3. Multiply the
test specimen volume by 10-6 to convert to l (Liters). Define the air volume of the test container in l. Divide the
test container volume by the test specimen volume. If the ratio does not equal the required ratio, then cut a
second test specimen the same size, double the thickness value and calculate the ratio as above. Use the
number of test specimens that comes the closest to the required ratio.
To calculate the test specimen weight according to Table 2: Weight the part to be tested in g and calculate
according the applicable formula.
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3.4 Test Time. (24± 0.5) h heating and 2 h cool down plus 168 h conditioning at room temperature before the
test can be started.
3.5 Test Required Information. For test required information see GMW16853, "3.1.7 Test Required
information".
3.6 Personnel/Skills. Not applicable.
4 Procedure
4.1 Preparation. See paragraph 3.3.
4.2 Conditions.
4.2.1 Environmental Conditions. See paragraph 4.3.
4.2.2 Test Conditions. Deviations from the requirements of this standard shall have been agreed upon. Such
requirements shall be specified on component drawings, test certificates, reports, etc.
4.2.2.1 Test specimens shall be produced immediately upon receipt of parts or materials and tested shortly
thereafter. In the event that testing cannot begin immediately, the pieces or parts to undergo testing shall be
wrapped in an impermeable, odorless material such as aluminum foil until testing begins. This way the as-
received or installation condition is checked.
4.2.2.2 If the received part has an odor rating < 6, when evaluated per the odor panel procedure, no testing is
required. The sample does not meet the requirements.
4.3 Instructions.
Note: This Test Procedure depends on coding A, B or C for test specimen conditioning.
To obtain consistent data, carefully select your odor panel. Odor panelists shall not smoke heavily, wear cologne
or perfume, chew gum or tobacco or have sinus problems. The odor test shall be performed in an area that is
odor free. Persons evaluating odor shall rate the specimens individually and not share information before the
last odor panelist has evaluated the specimens.
4.3.1 Wet Condition - Coding A.
4.3.1.1 Sufficient distilled or deionized water shall be placed in the test container, so as to ensure that some
water remains at end of test.
If a 1 l metal can is used, place ≈ 2 ml of distilled or deionized water in the can.
If an all glass container is used, the container size may vary. Calculate the volume of the glass container and
use enough distilled or deionized water to fit it ≈ 10 % by volume.
4.3.1.2 For a glass container the test specimen shall be placed on a support shelf or rack in the test container to
exclude direct contact by the test specimen with the water. It is not necessary to reduce the container volume
by the volume occupied by the support rack.
To prevent direct contact of the test specimen with the water when using the can, the water (2 ml) shall be put
in a small ceramic crucible on the bottom of the can.
4.3.1.3 Pressure seal the lid of the metal can. If a desiccator is used, tape the lid closed to prevent the lid from
sliding during storage. The test container shall then be placed in the oven for (24 ± 0.5) h at (+70 ± 2) °C.
4.3.2 Dry Condition - Coding B.
4.3.2.1 The test specimen shall be placed in the test container. For a 1 liter can, pressure seal the lid. If a
desiccator is used, avoid specimen contact with the bottom, and tape the lid closed to prevent the lid from sliding
during storage.
4.3.2.2 The test container shall then be placed in the oven operating for (24± 0.5) h at (+70 ± 2) °C.
4.3.3 High Temperature Condition - Coding C.
4.3.3.1 The test specimen shall be placed in the test container. For a 1 l can, pressure seal the lid. If a desiccator
is used, avoid specimen contact with the bottom, and tape the lid closed to prevent the lid from sliding during
storage.
4.3.3.2 The test container shall then be placed in the oven operating for (24 ±0.5) h at (+105 ± 2) °C.
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4.3.4 Control Container Procedure.
4.3.4.1 An empty test container shall be placed in the oven with the containers that are used to test the specimens
for odor. The empty containers shall be identical to the test containers with the specimens inside. It is not
necessary to include an empty test container that contains water.
4.3.4.2 The test container shall then be placed in the oven operating for (24 /-0.5) h at (+70 ± 2) °C.
4.3.5 Odor Testing. If 1 liter metal cans are used, the odor test may be performed immediately upon removal
from the oven. When evaluating odor, the (empty) control container shall be held ≈ 15 cm from the odor panelist´s
nose. With a cupped hand, draw the air from the can to the nose an inhale slowly. The lid shall not be of the can
for longer than five seconds. Immediately, repeat the procedure for the first specimen to be evaluated and record
the rating. After at least 2 minutes, repeat the process again for the next specimen.
Ensure that all metal cans have been pressure sealed and returned to the oven for at least 15 minutes before
the next odor panelist evaluates the odor.
If all glass containers are used, following the specified period in the oven the test containers shall be removed,
and allowed to remain out of the oven for a minimum of two hours at (+23 ± 5) °C before evaluating odor. Odor
panelists shall slide the top of the desiccators open far enough to allow the panelist to insert his/her nose and
close the lid quickly. Do not raise the lid off the desiccators. After each evaluation, it is not necessary to place
the desiccators in the oven between odor panelists.
5 Data
5.1 Calculations. Not applicable.
5.2 Interpretation of Results. Any odor shall be evaluated by six individual test persons using the classification
given below. No more than half of the "odor committee" shall be chemists.
Table 3: Odor Classification
Rating Description for all materials except leather Description for leather materials
10 Odorless Odorless
9 Just noticeable Just noticeable
8 Noticeable, trace Noticeable, trace
7 Clearly noticeable, but not objectionable Clearly noticeable, agreeable leather fragrance
6 Tolerable Typical leather fragrance
5 Borderline tolerable Leather fragrance
4 Objectionable Strong leather fragrance
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3 Annoying Annoying leather fragrance
2 Severe Very severe leather fragrance
1 Intolerable Intolerable
Optional: In addition to the rating a description of the odor can be made. See Appendix A for example evaluation
sheet. This description then shall be provided with the results.
Calculate the average of individual ratings (see paragraph 5.3).
If difference between highest and lowest ratings is greater than five units, test shall be repeated with different
evaluators, if possible.
All of the results from the first and second test shall then be averaged.
5.3 Test Documentation. With reference to this standard, the resistance to odor propagation shall be indicated
as the overall average of the mean four (4) individual ratings (i.e. the highest and the lowest individual rating
shall be omitted) rounded to one decimal place: x.0 or x.5 under consideration of the rounding rule.
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6 Safety
This Engineering Standard may involve safety requirements for hazardous materials, the method of operations
and equipment. This standard does not propose to address all the safety issues associated with its use. It is the
responsibility of the user of this standard to ensure compliance with all appropriate safety and health practices.
This would include any specific training that may be required. The safety and health standards include site
specific rules and procedures, company rules and procedures, and Government Standards. Contact shall be
made with the appropriate site Safety and Health personnel for further direction and guidance in these matters.
7 Notes
7.1 Glossary. Not applicable.
7.2 Acronyms, Abbreviations, and Symbols. Not applicable.
8 Coding System
This standard shall be referenced in other documents, drawings, etc., as follows:
For example:
"Test to GMW3205 Coding A"
Coding A: Conditioning according to paragraph 4.3
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9 Release and Revisions
This standard was originated in January 1999. It was first approved by WWW Interior Trim Team in June 1999.
It was first published in May 1999.
Issue Publication Date Description (Organization)
1 MAY 1999 Initial publication.
2 DEC 2000 Reformat revision (GMNA)
3 JAN 2011 Content completely revised.
4 FEB 2011 Paragraph 5.2: “4 test persons” changed to “six individual test persons”
5 AUG 2016 5 year refresh update
Paragraphs 3.4, 3.5 text added
Paragraph 4.2.2.2 added
Appendix B: Rating Scale according to VDA 270 added
Minor changes
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Appendix A
A1 Definition
A1.1 Odor Propagation. Odor propagation as determined by this test method shall be defined as the tendency
for a test material to release volatile constituents of a smell, when subjected to elevated temperatures and/or
high humidity.
Table A1: Example for Evaluation Sheet Odor Description
Additional information regarding GMW3205-Odor
Date: Tester:
Test-ID:
Please comment on the odor
1. How does it smell:
(e.g. sweat, burnt, fishy, aromatic, rotten, pleasant, unpleasant, sweet, sour, like amines, like solvents, oily, tar,
agricultural etc.)
2. How does it affect you?
(e.g. nose biting, nose refreshing, makes head dizzy, nauseating, makes one caught, eye irritating etc.)
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3. Further comments
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Appendix B
B1 Cross Reference to replaced Local Specifications
Rating of
GMW3205 VDA 270
1 6.0
2 5.0
3 4.5
4 4.0
5 3.5
6 3.0
7 2.5
8 2.0
9 1.5
10 1.0
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