Noise exposure of employees in retail trade
Jan SELZER(1) , Florian SCHELLE(1) , Andrea WOLFF(1) , Frank ROKOSCH(2) , Anne GEHRKE(3)(1) Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA), Germany, jan.selzer@dguv.de(2) German Social Accident Insurance Institution for Trade & Distribution Industry (BGHW), Germany, f.rokosch@bghw.de(3) Institute for Work and Health of the German Social Accident Insurance (IAG), Germany, anne.gehrke@dguv.de

Abstract
Noise can lead to extra-aural effects, which can diminish the health of employees in the long term. To protect
the employees from extra-aural noise effects, a new national regulation for measurement and rating of noise
at workplaces became active in Germany by means of a technical rule. In order to assess the situation of employees in retail trade, measurements of noise exposure were carried out following the mentioned technical ruleand ISO 9612. Personal sound exposure meters were used to determine the physical exposure at the ear of
employees. Stationary measurements next to the cashiers area were performed additionally. For psychologicalevaluation of working-condition-perception, a validated questionnaire (BASA II) was used. Furthermore, room
acoustic measurements were performed in representative retail stores as well as binaural recordings for psychoacoustic analysis purposes. Outcomes of this project will be presented and discussed for personal and stationary
sound pressure levels. Measurement method and rating of results in German legal requirements turned out tobe difficult to apply for these types of workplaces, as will be discussed in detail. In addition, the results of themeasurements and the questionnaire will be reviewed to show the relationship between perceptual and analyticalvariables.
Keywords: Noise, Workplace, extra-aural, Retail

1

INTRODUCTION

Employees in retail trade are exposed to different types of sounds in their everyday work. Depending on
the activity performed, the auditive input comes from different sound sources like customers talking, children
crying and screaming, the own and the tills beeps of the other colleagues and many other different sources.
To protect the employees from extra-aural effects, which do not affect aural damages to the inner ear, a newnational regulation for measurement and rating of noise at workplaces became active in Germany by means of atechnical rule. It is called “Technical Rule for Workplaces ASR A3.7 Noise” (short: ASR A3.7) [1] and is used
to protect employees at workplaces with an A-weighted sound pressure level lower than 80 dB. It concretes
the minimum requirements according to the German Workplaces Regulation. Measurements and evaluation ofsound pressure levels at workplaces above 80 dB are regulated in the “Ordinance on noise and vibrations
protection” and the according technical rules (short: TRLV noise) [2]. Those technical rules are connected tothe measurement methods described in ISO 9612:2009 [3] evaluating the daily noise exposure level LEX,8h as
descriptor for protection of aural health. Sound pressure levels lower then 80 dB were expected in this projectin retail trade, but still ISO 9612 is important for this paper, because of different lacks in the measurement
method of ASR A3.7.
The aim and motivation for this project is first to capture the exposition of employees in retail trade systematically, especially in textile and food retail. First, there is a huge interest from the occupational safety and healthpoint of view. Despite the changing world of work, noise is one of the most widespread reasons for complaints.
Second, since the release of ASR A3.7 media and trade unions demand for better protection of employees inretail trade in Germany.

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2

METHOD AND MEASUREMENTS

To capture the noise exposure of employees in retail trade, measurements are performed by the responsible
occupational noise measurement service of the German Social Accident Insurance Institution for Trade & Distribution Industry and IFA in the period of time from March to September 2018. Following measurands are
determined• A-weighted sound pressure level at employees ears, measured with personal sound exposure meters,• A-weighted and A- and impulse-time-weighted sound pressure level in the cashiers area, measured stationary,• reverberation time in representative retail stores,• psychological evaluation of working-condition-perception with the help of a validated questionnaire [4].
Additionally binaural recordings are performed in representative retail stores for psychoacoustic analysis purposes. A special focus is set to the first three points of this enumeration. The different methods for determining
the above mentioned points are presented subsequent.
2.1 Person-related measurements
Activities carried out by employees in retail trade are rarely stationary, except cashing. Therefore, measurementswith personal sound exposure meters are performed. To ensure the correct position of the personal sound exposure meter according to ISO 9612 [3], suspenders are used. The correct position is very important for thedetermination of the correct sound exposure. With retail sector specific knowledge of the corresponding social
accident insurance institution diverse activities are collected into a catalogue: stocking goods, cashing, storage
activities, garbage disposal, breaks, cleaning, sales. This activity-catalogue helps to observe the employees during
the measurements with personal sound exposure meters and is needed for the activity-based evaluation of themeasurements. In addition, sound pressure level profile sections can be evaluated considering the relevant activities and not only as a whole job-based measurement. Inherent noise is not excluded from the measurements, as
demanded by ASR A3.7 [1], because of manifold reasons: first, a large part of the activities carried out causes
inherent noise, like cashing, sales and stocking goods onto their sale-places. Second, the definition of inherent
noise by ASR A3.7 is not clearly differentiated for those types of workplaces [1]. For that reasons the physicalexposure to the employees ears is the result of those measurements.
2.2 Stationary measurements in cashiers area
Stationary measurements are performed in the cashiers area. Therefore, sound level meters are located at nonoccupied tills. The measurands are L pAIeq and L pAeq .
2.3 Room acoustics measurements
Measurements of reverberation times are conducted in representative retail stores of both branch sectors during the opening hours. Room impulse responses are collected with MLS method (maximum length sequence).
Reverberation times are calculated from the room impulse responses.
2.4 Binaural recordings
For psychoacoustic analysis purposes binaural recordings with an artificial head are performed in representative
retail stores, especially in the cashiers area. Those recordings will also be used for further investigations andlistening tests.

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2.5 Questionnaire: working-condition-perception of employees
To inspect the employees working-condition-perception, a validated questionnaire is used. BASA II is a screening procedure used for determination of promotional and impairing conditions at work [4]. 16 items are added
to the survey to highlight the topic “noise exposure” in more detail. Furthermore, the German short noisesensitivity questionnaire with nine items is added as well [6]. The questionnaire encompasses 128 items in
total. The employees respond anonymously and online using a provided tablet during working time and after
the measurements. No personal data is collected.

3

GERMAN NATIONAL REGULATION: ASR A3.7

For presenting the actual stage of this project, an overview of German national regulations is essential. Releasedin May 2018, during the already ongoing project, the Technical Rules for Workplaces ASR A3.7 “Noise” defines
the minimum requirements for protection of employees from extra-aural effects [1]. The requirements are split
in two parts: first there is the so called “rating level” Lr , which is defined for three different types of activities(“activity-categories”) and must not be exceeded. Second, there are prescribed reverberation times depending on
the room usage.
The “rating level” Lr is defined as the A-weighted equivalent sound pressure level with penalties for tonal andinformation-containing noise (KT ) as well as for impulse noise (KI ) (Equation 1).
Lr = L pAeq + KI + KT

(1)

KI is calculated from the difference between the A- and impulse-time-weighted (time-weighting with τ↑ = 35 ms,τ↓ = 1500 ms) and A-weighted sound pressure level. This difference is only evaluated and added to L pAeq if it
is between three and six decibels. Values lower then three are set to zero and values higher then six are set tosix decibels (Equation 2).
0
KI = L pAIeq − L pAeq


6

if
if
if

(L pAIeq − L pAeq ) < 3 dB
3 dB ≤ (L pAIeq − L pAeq ) ≤ 6 dB
(L pAIeq − L pAeq ) > 6 dB

(2)

The penalty for tonal and information-containing noise KT is evaluated subjectively by the person performing
the measurement. It is possible to set the penalty to 3 or 6 dB, dependent on the perceived prominence of theinformation-containing or tonal noise at the workplaces. The sum of both penalties KI + KT is limited to 6 dB.
In ASR A3.7 three categories of activities are mentioned. The activity-category I is characterized as “highconcentration or high speech intelligibility”, e.g. “making decisions with high impact under time pressure,formulation and/or understanding of complex texts, ...”. For this activity-category a rating level of 55 dB mustnot be exceeded. “Mid concentration or mid speech intelligibility” is demanded for the fields of activities in
the category II. The rating level limit is set to 70 dB for activities like “making decisions with low impact andwithout time pressure, easy to process, recurring tasks, ...”. For the activity-category III rating levels must be
reduced as far as possible, taking into account noise abatement measures. This category is described as “lowconcentration or low speech intelligibility” and includes routine and simple work.
The measurement method for evaluation of the rating level relates to DIN 45645-2 [5]. After analysing thefields of activity, which are carried out cumulatively for at least one hour on a representative working day, ameasurement of the sound pressure level in the height of the employees ears excluding the inherent noise isnecessary. Inherent noise is described as “noise as a result of conversations with other persons and communication
signals assigned to the workstation, e.g. telephone, computer keyboard, ...”. To exclude those inherent signals
during a measurement, the measurement has to be interrupted. Otherwise a measurement has to be performed
without the employee in question and its communication equipment. The penalties are calculated after themeasurement in the way described above. Finally, the rating level can be determined and compared with the7074

limit value of the corresponding activity-category.
For room acoustics purposes there are reverberation times defined for the octave bands from 250 Hz to 2000 Hz
for four different types of room usage (Table 1), which should not be exceeded. Three refer to offices and one
to educational institutions. One room usage is referred as “other rooms with usage for communication” with avalue of ᾱ ≥ 0.3 in the above mentioned frequency range.
Table 1. Reverberation times T in the octave bands from 250 Hz to 2000 Hz for different room types, whichshould not be exceeded according to ASR A3.7 [1]; with V as room volume in m3
Room usage
Call center
Multi-person and open plan office
One- or two-person office
Educational institutions

4

T
0.5
0.6
0.8
(0.32 · log(V ) − 0, 17) s

tolerance± 20 %EVALUATION AND RESULTS

4.1 Person-related measurements
Table 2. Overview: number and duration of personal sound exposure meter measurements
Retail sector
Measurement location
Number of measurements
Measurements with activity-based evaluation
Measurement duration [hh:mm:ss]

Food
12
26
15
53:28:07

Textile4
16
14
33:14:58

In total, approximately 87 hours of measurements with personal sound exposure meters are conducted in textile
and food retail. In Table 2 measurement locations, meaning the number of different retail shops, and the over
all number of measurements with personal sound exposure meters are shown. An activity-based evaluation is
not possible for all measurements performed, because of insufficient logging of activities or because of activity
combinations during the measurements.
Table 3. Activity-based measurement results of person-related measurements in food retail; arithmetic average
LAeq , standard deviation (SD) σ (LAeq ) and measurement duration t
Activity
Stocking goods
Cashing
Storage activities
Garbage disposal
Break
Cleaning
Sales

Arithmetic average [dB]
72,3
72,0
72,8
77,0
66,5
67,1
73,8

SD [dB]
4,0
4,7
4,2
7,8
3,1
6,9
7,7

t [min]
715,4
656,8
157,6
21,7
126,1
7,5
39,9

The activities cashing and stocking goods have the highest measurement duration independent of branch sector(Tables 3 and 4). Nevertheless, the deviation between the exposure at the employees ears, described by thesound pressure level LAeq as arithmetic mean for one activity across all stores of one branch sector, is small.

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90�����������������
87.5 o mean
x single measurement
85
I u
82.5
80
� 77.5"'d._____.� 75
72.5
70
67.5
65
62.5
60'-----'----.c____-'------L------'------'-------L..-----L..-----L-----'-------'------"-------"-------"-------L----'....,, 'v '\, '\,'v....,,,, ....,,"v' ....,,"v ,"v� ....,,"v�,�' � � $' �� 'v....,, "v' 'v'v 'v�
Retail Store
X

4

Cl.)

X
X

$

Figure 1. Evaluation of single measurements LAeq as energy-equivalent mean per retail store (code foranonymity) with combined standard uncertainty u according to [3] and single measurements “×”.
Therefore, no differentiation based on activity is possible. On that account an energy-equivalent mean per retailstore and the appurtenant combined standard uncertainty according to strategy 2 “job-based measurement” ofISO 9612 is calculated (Figure 1). High combined standard uncertainties are justified by a small amount of
single measurements in the particular retail store wit a quiet high deviation from one another.
Table 4. Activity-based measurement results of person-related measurements in textile retail; arithmetic average
LAeq , standard deviation (SD) σ (LAeq ) and measurement duration t
Activity
Stocking goods
Cashing
Storage activities
Sales

Arithmetic average [dB]
72,0
74,0
71,6
71,3

SD [dB]
3,6
1,4
3,1
3,1

t [min]
745,1
850,8
99,0
52,4

4.2 Stationary measurements in cashiers area
The arithmetic average A-weighted sound pressure levels in the cashiers area are 63.8 dB (min: 58.7 dB, max:
67.7 dB) for food and 62.3 dB (min: 57.3 dB, max: 67.9 dB) for textile retail sector. The difference between
LAIeq − LAeq for the evaluation of a possible penalty KI is higher than 6 dB, independent of the branch sector(Figure 2). For the activity cashing a penalty of 6 dB is necessary for calculation of a possible rating level Lr .
The noises contributing to the impulse penalty are, among others, the customer conversations, the music andadvertising announcements.
4.3 Room acoustics measurements
The determination of the room acoustic parameters during opening hours shows ᾱ ≥ 0.5 in all relevant octave
bands. Thus the target values according to ASR A3.7 are more than achieved. Those high values can be reached7076

Figure 2. Boxplot: difference between LAIeq − LAeq in cashiers area for stationary measurements with arithmetic
average “×” and an outlier “◦” from 22 stationary measurements in food and 18 in textile retail.
due to absorptive ceilings in nearly every retail store. Additionally, in textile retail garments have an absorptive
effect and in food retail the shelves help to inhibit sound propagation.

5

CONCLUSIONS AND DISCUSSION

The person-related measurement results show, that a differentiation on activity-basis is neither useful nor meaningful. Additionally, the measurement observers could have different interpretations of one and the same situation. A central data analysis of various measurements could also lead to misinterpretations. For example, asales conversations could be catalogued as sales or stocking goods, if the employee is stocking goods and helps
out a customer to find the product of interest.
Therefore, an evaluation of the results on a retail store basis is more useful and represents the effective, physicalexposure at the employees ears in each retail store. The evaluation of the rating level according to ASR A3.7
[1] is questionable, because of the exclusion of the inherent noise. This inherent noise has a high temporalshare within the executed activities. It is not only the communication with the customers or colleagues, it isalso questionable which sound can be classified as inherent. The tills beeps for example can be apprehended
as an acoustic feedback to the employee, but it can also be a stressor. Furthermore, the definition of inherent
noise and the measurement method described in ASR A3.7 and DIN 45645-2 do not work for activities in retailtrade and is better applicable in office situations [1][5]. Performing measurements in absence of for example anemployee at the till is not that easy. The absence of the employee also entails the absence of the customers at
the checkout. There is no sound coming from talking customers and unloading the shopping cart on the belt.
Those and other difficulties have to be considered.
The stationary measurements show a situation comparable with the one demanded by ASR A3.7 at a nonoccupied till. Nevertheless, the measurement conditions can be incomparable among one another, because ofdifferent distances to the real workplace and different in-situ setup conditions of the sound level meters. However, the stationary measurements indicate a sound pressure level area from 57 to 68 dB. Calculating a ratinglevel a penalty of 6 dB has to be considered for the activity cashing.

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Noise abatement using room acoustic measures is not expedient, since nearly all retail stores do have absorptive
ceilings and the room acoustic situations are adequate. Other noise abatement measures could also help, like• insulating mats inside of collecting containers for clothes hangers or anti-theft tags,• stop dampers for cash drawers,• no positioning of freezers and bottles-/cans-deposit-machines in immediate proximity to the cashiers area,• tills beeps can be adjusted in sound pressure level.
In the further project progress the analytical variables will be connected to the perception-based parameters evaluated with the help of the questionnaire. A precise contemplation of the psychoacoustic analysis in combination
with the perceptual evaluation will be prepared. The monaural worn headset has also proved to be a challenge
for occupational safety and health in the retail trade.

REFERENCES[1] Technical Rules for Workplaces ASR A3.7 “Noise” [Technische Regeln für Arbeitsstätten ASR A3.7
“Lärm”], Federal Institute for Occupational Safety and Health, Germany, 2018.
[2] Technical Rules on Ordinance on noise and vibration protection, Part Noise [Technischen Regeln zur Lärm
und Vibrationsarbeitsschutzverordnung, Teil Lärm], Federal Institute for Occupational Safety and Health,Germany, 2017.
[3] ISO, International Standard ISO 9612: Acoustics – Determination of occupational noise exposure – Engineering method, Switzerland, 2009.
[4] Richter, G.; Schatte, M. Psychological Evaluation of Working Conditions – Screening for Occupants ofWorkplaces II (BASA II), Federal Institute for Occupational Safety and Health [BAuA], Dortmund (Germany), 2011.
[5] DIN, German National Standard DIN 45645-2: Acoustics – Determination of rating levels from measurement data - Part 2: Determination of the noise rating level for occupational activities at the work place forthe level range underneath the given risk of hearing damage, Germany, 2012.
[6] Zimmer, K.; Ellermeier, W. A short questionnaire to determine the noise-sensitivity [Ein Kurzfragebogen
zur Erfassung der Lärmempfindlichkeit], Umweltpsychologie, Vol 2 (2), 1998, pp 54-63.

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