ASTM E1593-94(1999)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:E1593–94 (Reapproved 1999)
Standard Practice for
Assessing the Efficacy of Air Freshener Products in
Reducing Sensorily Perceived Indoor Air Malodor Intensity
This standard is issued under the fixed designation E1593; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 1.6 Air freshener products are sold commercially with the
intent of providing a means of improving the odor quality of a
1.1 This practice covers standardized procedures for the
volume of air, relative to some existing environmental condi-
quantitative sensory assessment of the reduction of perceived
tion. This typically involves the application of an odorous
olfactory intensity of indoor malodors, for the purpose of
substance into the air space by means of some mechanical or
assessing the deodorant efficacy of air freshener products.This
physical mechanism. When the existing environment includes
practice is confined to static conditions only.
some undesirable odor source, or malodor, reduction of the
1.2 The determination of this efficacy can be useful for
perception of the malodor is usually accomplished with other
establishing performance claims for a given formulation, and
odorous substances by masking. This procedure is also appli-
for substantiation of those claims in product advertising.
cable to other mechanisms of odor reduction.
However, one must be aware that certain types of claims exist
1.7 Thepurposeofthispracticeistoassesstheabilityofair
that this type of testing will not support.
freshener products to reduce indoor air malodor intensity from
1.3 This practice is limited to the assessment of a specific
a control state. Several experimental hypotheses are possible,
malodorintensitybytrainedjudgesundercontrolledlaboratory
dependingontheobjectiveofthetest.Possibleobjectiveswith
conditions. Methods that reflect actual consumer environmen-
respective hypotheses are given in Appendix X1.
talconditionsarevalidforselectedsensorytasks,buttheymay
1.8 This standard does not purport to address all of the
be less sensitive. Methods that include highly controlled
safety concerns, if any, associated with its use. It is the
environmentalconditionswillincreasethechancesofdetecting
responsibility of the user of this standard to establish appro-
small differences among treatments. The degree of control of
priate safety and health practices and determine the applica-
extraneous experimental factors in an experiment is variable
bility of regulatory limitations prior to use. Specific precau-
andisgovernedbythepurposeofthetest,amountofresources
tionary statements are given in Section 6 and X3.6.3.7.
availabletoprovidethatdegreeofcontrol,anddesiredlevelof
statistical sensitivity (see Appendix X3).
2. Referenced Documents
1.4 Selectionofrepresentativemalodorsourcesisofcritical
2.1 ASTM Special Technical Publications.
importance. The malodor source must be readily available and
STP 434, Manual on Sensory Testing Methods
of a consistent odor quality. A reasonable malodor source
STP 758, Guidelines for the Selection and Training of
should be chemically and aesthetically correct. The experi-
Sensory Panel Members
menter and client must agree upon the appropriateness of a
STP 913, Physical Requirement Guidelines for Sensory
malodor source before further details of the test design are
Evaluation Laboratories
worked out. Experimental variation will be reduced by using
uniform malodor sources. Information collected on malodor
3. Terminology
reduction will thus be more comparable from experiment to
3.1 Definitions:
experiment and from laboratory to laboratory.
3.1.1 activation time—the length of time that a product is
1.5 It is recognized that, while sometimes desirable, the use
permitted to be exposed in a chamber prior to evaluation by
of actual “live” malodors is often impractical due to the
panelists.
inherent variability of the malodor sources. A true malodor
3.1.2 malodor—an olfactory stimulant that, when detected,
source may be used when practical. However, the use of a
is considered unpleasant or undesirable by the target popula-
formulated odor source has several advantages, including
tion.
consistency and availability.
3.1.3 malodor control—atreatmentconsistingofachamber
containing a malodor without any additional treatment.
This practice is under the jurisdiction of ASTM Committee E18 on Sensory
Evaluation of Materials and Products and is the direct responsibility of Subcom-
mittee E18.07 on Personal Care and Household Evaluation.
Current edition approved Feb. 15, 1994. Published April 1994. Available from ASTM, 100 Barr Harbor Drive, Conshohocken, PA 19428.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E1593
3.1.4 malodor reduction effıcacy—the degree to which a est, and availability for testing. This screening of potential
product treatment or process reduces perceived malodor inten- panelists should be divided into two phases (interview and
sity.
testing). The two phases should be conducted as separate
3.1.5 masking—the reduction or elimination of olfactory
sessions (see STP 758 for panelist selection considerations).
perception of a defined odor stimulus by means of another
7.2 Panelist Recruitment—In order to ensure an adequate
odorous substance without the physical removal or chemical
number of panelists for testing, a larger number should be
alteration of the defined stimulus from the environment.
recruited. This is to offset the attrition experienced in inter-
3.1.6 product control—a treatment consisting of a chamber
viewing, testing, and training based on the assumption that
containing product only.
roughly half the number of recruits will fail.Afinal number of
3.1.7 spraytime—thelengthoftimeinsecondsforwhichan
panelists should be selected in advance. A panel size of 20 is
aerosol air freshener is sprayed with the actuator depressed
typically recommended for a scaling experiment. Refer to STP
fully.
434 or Kraemer and Thieman (1), or both, for other consid-
3.1.8 synthetic model—a mixture of components used to
erations affecting sample size.
represent an odor.
7.3 Interview (15 min)—During the interview, it is impor-
4. Summary of Practice tantthatthejudgefullyunderstandthenatureofthetestingfor
which she/he is volunteering, including the types of malodors
4.1 The procedures described herein provide for the selec-
to be used in malodor testing. In addition, she/he should be
tionofindividualsandtheirtrainingtoperformthefunctionsof
made aware of and agree to the time commitment expected,
judges,andforthepresentationoftreatedoruntreatedsamples,
scheduling of testing, and “good testing practices” such as the
or both, to these judges, in order to evoke an assessment of
following: refraining from smoking for at least 1 h before
perceived malodor intensity. These assessments are performed
testing, refraining from wearing perfume or after-shave on the
under controlled laboratory conditions in order to determine
the effect of a given product in reducing the intensity of a dayoftesting,etc.Ashortquestionnaireregardingtheperson’s
physical health should be administered to determine whether
standard malodor intensity.
4.2 Airfreshenerproductsshouldbetestedinamannerthat the candidate has nasal or upper respiratory allergies, asthma,
maximizes test sensitivity while remaining consistent with or is prone to frequent colds. These conditions may result in a
normal product usage.
decrease in judge sensitivity.
7.4 Testing—The key concept in this phase of screening is
5. Significance and Use
to ensure that the panelists are able to (1) discriminate and (2)
5.1 The procedure recommended can be used for assess-
detect the malodorant(s) being studied. One example of how
ment of the malodor efficacy of an air freshener product on
this can be accomplished is by using a sequential analysis
either an absolute or relative basis.
technique (2).
5.2 These procedures are applicable in the assessment of
7.4.1 Recruits should be tested to determine their ability to
any products that reduce the perception of any malodor,
detect and discriminate the malodors of interest. Appropriate
regardless of the mode of action.
testing methods for assessing ability include discrimination,
5.3 The determination of product efficacy can be useful in
ranking, or intensity scaling, or combination thereof.
several situations, including product development, substantia-
7.4.2 The malodorant(s) in question should be the focus of
tion of performance claims in product advertising to consum-
the screening. Several concentrations of each of the malodor-
ers, and facilitation of communication of efficacy among
ant(s) should be chosen for this testing. The concentrations
product manufacturers and suppliers.
should be representative of intensities experienced during
5.4 These procedures are applicable to aerosol/spray and
regular malodor efficacy testing. Different levels of difficulty
continuous/solid air freshener products. It should be noted that
should be included in the test set. Each level of difficulty is
while aerosol/spray and continuous/solid product evaluations
established by pretesting.
are fundamentally the same, differences in technique are
necessary due to the difference in the product delivery system.
7.4.3 Selected concentrations of each of the malodorants
5.5 These procedures can be used to assess efficacy against
should be presented to recruits in a manner consistent with the
any standard malodor.
difference testing procedure described in STP 434.
7.4.4 The selection of panelists should first rest on the
6. Precautions
results of the acuity testing. Additional tests for selected
6.1 Extreme care should be taken when handling and
panelists may be necessary to accept or reject them. (That is,
preparing samples under conditions that will maintain the
their performance may indicate the need for more testing.) If
odorless state of the laboratory area.
the number of recruits is greater than required, the additional
6.2 Appropriate safety precautions should be taken when
information gained from the interview process should be
handling all chemical compounds.
applied.
7. Selection of Panelists
7.1 Purpose—Thepurposeofthisseriesoftestsistoscreen
potential panelists for a malodor efficacy panel. The screening
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
is for olfactory acuity, specific anosmia to malodorants, inter- this standard.
E1593
8. Training of Panelists its own merit. It is not within the scope of this practice to
enumerate the details of all techniques. However, it is impera-
8.1 Purpose—The purpose of the experimental procedures
tive that the results should indicate clearly that the synthetic
discussed here is to recommend a program of training for a
mixture is reasonably similar to the actual malodor as experi-
group of qualified people to act as malodor efficacy panelists.
enced by the consumer.
8.2 Panelist training is accomplished in three phases: (1)
9.2 The following criteria may be used to validate the
orientation, (2) mock deodorancy studies, and (3) regular
choice of malodorant(s). One or all of these criteria may be
monitoring of panelist performance (see STP 758 for panelist
appropriate, depending on the specific mode of action of the
training considerations).
products.
8.2.1 Orientation—Abrief orientation session may be held
9.2.1 Chemical Composition—If the product is meant to
for the trainees. The objective of the orientation is to familiar-
izethepanelistswiththetaskofevaluatingmalodorefficacyas function by some physical method (other than masking), the
chemical composition of the malodor model is critical. The
fully as possible in order to reduce the experimental error.The
objective can be achieved by doing such things as introducing chemical compositions of the malodor model and samples of
theactualmalodorsourceshouldbedeterminedbyappropriate
the panelists to each other and to test personnel involved in
conducting malodor efficacy, explaining the purpose of mal- analytical methods. Similarities and differences should be
noted and evaluated for relative importance.
odor efficacy testing in the company, orienting and training
judges to the selected rating scale, discussing typical testing
9.2.2 Multiple Choice Data—The data generated from a
procedures, describing panelist’s responsibilities, and provid-
multiple choice descriptor panel can be used to support a
ing a tour of the facilities used to conduct malodor efficacy
potential malodor model. Malodor samples should be pre-
testing.
sented at appropriate intensities. The number of panelists,
8.2.2 Mock Effıcacy Study—One or more mock studies may
malodor samples, and possible descriptors should be consid-
be arranged to give the panelists the opportunity to practice
ered before beginning any such test. Other factors to consider
making efficacy evaluations. Products for testing should have
include the sample presentation, descriptor terms, and accep-
known differences and may include all types of air care
tancecriteria.Foranexampleballotandprofiles,seeAppendix
products.The study may be similar to an actual efficacy test in
X2.
order to smooth the transition from training to regular testing.
9.2.3 Odor Profile Data—The data generated from an odor
Panelists should be given the opportunity to practice and
profile panel can also be used to support a potential malodor
demonstrate the ability to make odor intensity judgments. In
model. Although this procedure is more time- and resource-
addition, through discussion and feedback, panelists should be
intensive, it will provide more detailed information on major
trained to “smell through” any extraneous odor(s), such as the
and minor odor descriptors that are detected in a potential
fragrance of the product, to evaluate malodor intensity. Indi-
malodor model. The considerations discussed relative to the
vidual panelist performance can be monitored during the
multiplechoicetestsshouldalsobeconsideredforodorprofile
training phase by analyzing for variance due to panelists.
tests.Forinformationconcerningodorprofiling,seeDravnieks
Individuals who exhibit errant results should undergo addi-
(3) or Jeltema and Southwick (4), or both.
tional training and monitoring. However, repeated underper-
9.3 Toxicological Review—The synthetic model should be
formers should be dropped from the panel.
subjected to a safety review by the appropriate health and
safety professio
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