ECMA-74
19th Edition / December 2021

Measurement of
Airborne Noise emitted
by Information
Technology and
Telecommunications
Equipment

Reference number
ECMA-123:2009© Ecma International 2009

Contents

Page

1

Scope ...................................................................................................................................................... 1

2

Normative references ............................................................................................................................ 2

3
3.1
3.2
3.3

Terms and definitions ........................................................................................................................... 3
General definitions ................................................................................................................................ 3
Acoustical definitions ........................................................................................................................... 5
Definitions related to uncertainty ........................................................................................................ 8

4

Conformity requirements...................................................................................................................... 8

5
5.1
5.1.1
5.1.2
5.1.3
5.1.4
5.1.5
5.1.6
5.1.7
5.2
5.3

Installation and operating conditions ................................................................................................. 9
Equipment installation .......................................................................................................................... 9
General ................................................................................................................................................... 9
Floor-standing equipment .................................................................................................................... 9
Table-top equipment ........................................................................................................................... 10
Wall-mounted equipment.................................................................................................................... 10
Rack-mounted equipment .................................................................................................................. 10
Hand-held equipment .......................................................................................................................... 10
Sub-assemblies ................................................................................................................................... 10
Input voltage and frequency .............................................................................................................. 11
Equipment operation ........................................................................................................................... 11

6
6.1
6.2
6.3
6.3.1
6.3.2
6.4
6.4.1
6.4.2
6.4.3
6.4.4
6.4.5
6.4.6
6.5
6.6
6.6.1
6.6.2

Method for determination of sound power levels of equipment in reverberation test rooms .... 12
General ................................................................................................................................................. 12
Measurement uncertainty ................................................................................................................... 12
Test environment ................................................................................................................................. 12
General ................................................................................................................................................. 12
Meteorological conditions .................................................................................................................. 13
Instrumentation ................................................................................................................................... 13
General ................................................................................................................................................. 13
The microphone and its associated cable ........................................................................................ 13
Frequency response of the instrumentation system ....................................................................... 13
Reference sound source..................................................................................................................... 13
Filter characteristics ........................................................................................................................... 13
Calibration ............................................................................................................................................ 14
Installation and operation of equipment: General requirements ................................................... 14
Microphone positions and source locations .................................................................................... 14
General ................................................................................................................................................. 14
Number of microphone positions, reference sound source locations and equipment
locations ............................................................................................................................................... 14
6.6.3 Microphone arrangement ................................................................................................................... 14
6.7
Measurement of sound pressure level .............................................................................................. 15
6.7.1 General ................................................................................................................................................. 15
6.7.2 Measurement time interval ................................................................................................................. 15
6.7.3 Corrections for background noise .................................................................................................... 15
6.8
Measurement of the sound pressure level of the reference sound source .................................. 15
6.9
Calculation of the mean time-averaged band sound pressure levels ........................................... 15
6.10
Determination of sound power level ................................................................................................. 15
6.10.1 Calculation of band sound power levels ........................................................................................... 15
6.10.2 Calculation of A-weighted sound power level .................................................................................. 16
7
7.1

Method for determination of sound power levels of equipment under essentially free-field
conditions over a reflecting plane ..................................................................................................... 18
General ................................................................................................................................................. 18© Ecma International 2021

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7.2
7.3
7.3.1
7.3.2
7.4
7.4.1
7.4.2
7.4.3
7.4.4
7.4.5
7.4.6
7.5
7.6
7.6.1
7.6.2
7.7
7.7.1
7.7.2
7.7.3
7.8
7.9
7.9.1
7.9.2

Measurement uncertainty .................................................................................................................. 19
Test environment ................................................................................................................................ 19
Essentially free field over a reflecting plane .................................................................................... 19
Meteorological conditions ................................................................................................................. 20
Instrumentation ................................................................................................................................... 21
General ................................................................................................................................................. 21
The microphone and its associated cable ....................................................................................... 21
Frequency response of the instrumentation system ...................................................................... 21
Reference sound source .................................................................................................................... 21
Filter characteristics ........................................................................................................................... 21
Calibration ........................................................................................................................................... 21
Installation and operation of equipment: General requirements ................................................... 21
Measurement surface and microphone positions ........................................................................... 22
General ................................................................................................................................................. 22
Microphone positions on the measurement surface ...................................................................... 23
Measurement of sound pressure levels ........................................................................................... 23
General ................................................................................................................................................. 23
Measurement time interval ................................................................................................................ 23
Corrections for background noise .................................................................................................... 23
Calculation of surface time-averaged sound pressure level ......................................................... 24
Determination of sound power levels ............................................................................................... 24
Calculation of band time-averaged sound power levels ................................................................ 24
Calculation of A-weighted sound power level ................................................................................. 24

8
8.1
8.2
8.3
8.3.1
8.3.2
8.4
8.5
8.6
8.6.1
8.6.2
8.6.3
8.6.4
8.7
8.7.1
8.7.2
8.7.3
8.8
8.8.1
8.8.2
8.8.3

Method for determination of emission sound pressure levels at defined operator andbystander positions ............................................................................................................................ 24
General ................................................................................................................................................. 24
Measurement uncertainty .................................................................................................................. 25
Test environment ................................................................................................................................ 26
General ................................................................................................................................................. 26
Meteorological conditions ................................................................................................................. 26
Instrumentation ................................................................................................................................... 26
Installation and operation of equipment .......................................................................................... 26
Microphone positions ........................................................................................................................ 27
General ................................................................................................................................................. 27
At the operator position(s) ................................................................................................................. 27
At the bystander positions ................................................................................................................ 27
Microphone orientation ...................................................................................................................... 28
Measurement of sound pressure levels ........................................................................................... 29
General ................................................................................................................................................. 29
Measurement time interval ................................................................................................................ 30
Corrections for background noise .................................................................................................... 30
Determination of emission sound pressure levels ......................................................................... 30
Calculation of band emission sound pressure levels..................................................................... 30
Calculation of A-weighted emission sound pressure levels from band levels ............................ 30
Calculation of the mean emission sound pressure level at the bystander positions ................. 31

9

Measurement uncertainty .................................................................................................................. 31

10
10.1
10.1.110.1.210.1.310.1.410.1.5
10.2

Information to be recorded and reported ......................................................................................... 32
Information to be recorded ................................................................................................................ 32
General ................................................................................................................................................. 32
Equipment under test ......................................................................................................................... 33
Acoustical environment ..................................................................................................................... 33
Instrumentation ................................................................................................................................... 34
Acoustical data ................................................................................................................................... 34
Test report ........................................................................................................................................... 36

Annex A (normative) Test accessories .......................................................................................................... 39
A.1
Standard test table.............................................................................................................................. 39
A.2
Typing robot ........................................................................................................................................ 40ii© Ecma International 2021

Annex B (normative) Measurement surfaces ................................................................................................. 43
B.1
Hemispherical measurement surface ................................................................................................ 43
B.2
Cylindrical measurement surface ...................................................................................................... 44
B.2.1 General ................................................................................................................................................. 44
B.2.2 Selection of size of cylindrical measurement surface ..................................................................... 44
B.2.3 Selection of microphone positions on the cylindrical measurement surface .............................. 45
B.2.4 Calculation of the mean time-averaged sound pressure level over the cylindricalmeasurement surface ......................................................................................................................... 46
Annex C (normative) Installation and operating conditions for specific equipment categories .............. 49
C.1
General ................................................................................................................................................. 49
C.2
Equipment category: Typewriters ..................................................................................................... 52
C.2.1 Description ........................................................................................................................................... 52
C.2.2 Installation ............................................................................................................................................ 52
C.2.3 Operation .............................................................................................................................................. 53
C.2.4 Measurement time interval ................................................................................................................. 54
C.3
Equipment category: Character and line printers ............................................................................ 55
C.3.1 Description ........................................................................................................................................... 55
C.3.2 Installation ............................................................................................................................................ 55
C.3.3 Operation .............................................................................................................................................. 56
C.3.4 Measurement time interval ................................................................................................................. 58
C.4
Equipment category: Teleprinters ..................................................................................................... 59
C.4.1 Description ........................................................................................................................................... 59
C.4.2 Installation ............................................................................................................................................ 59
C.4.3 Operation .............................................................................................................................................. 59
C.4.4 Measurement time interval ................................................................................................................. 60
C.5
Equipment category: Keyboards ....................................................................................................... 61
C.5.1 Description ........................................................................................................................................... 61
C.5.2 Installation ............................................................................................................................................ 61
C.5.3 Operation .............................................................................................................................................. 61
C.5.4 Measurement time interval ................................................................................................................. 61
C.5.5 Measurement uncertainty ................................................................................................................... 61
C.6
Equipment category: Copiers (duplicators) ..................................................................................... 62
C.6.1 Description ........................................................................................................................................... 62
C.6.2 Installation ............................................................................................................................................ 62
C.6.3 Operation .............................................................................................................................................. 63
C.6.4 Measurement time interval ................................................................................................................. 64
C.7
Equipment category: Card readers and card punches ................................................................... 65
C.7.1 Description ........................................................................................................................................... 65
C.7.2 Installation ............................................................................................................................................ 65
C.7.3 Operation .............................................................................................................................................. 65
C.7.4 Measurement time interval ................................................................................................................. 65
C.8
Equipment category: Magnetic tape units ........................................................................................ 66
C.8.1 Description ........................................................................................................................................... 66
C.8.2 Installation ............................................................................................................................................ 66
C.8.3 Operation .............................................................................................................................................. 66
C.8.4 Measurement time interval ................................................................................................................. 67
C.9
Equipment category: Disk units and storage subsystems ............................................................. 68
C.9.1 Description ........................................................................................................................................... 68
C.9.2 Installation ............................................................................................................................................ 68
C.9.3 Operation .............................................................................................................................................. 68
C.9.4 Measurement time interval ................................................................................................................. 69
C.10
Equipment category: Visual display units and terminals ............................................................... 70
C.10.1 Description ........................................................................................................................................... 70
C.10.2 Installation ............................................................................................................................................ 70
C.10.3 Operation .............................................................................................................................................. 70
C.10.4 Measurement time interval ................................................................................................................. 70
C.11
Equipment category: Electronic units ............................................................................................... 71
C.11.1 Description ........................................................................................................................................... 71
C.11.2 Installation ............................................................................................................................................ 71© Ecma International 2021

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C.11.3 Operation ............................................................................................................................................. 71
C.11.4 Measurement time interval ................................................................................................................ 71
C.12
Equipment category: Microform readers ......................................................................................... 72
C.12.1 Description .......................................................................................................................................... 72
C.12.2 Installation ........................................................................................................................................... 72
C.12.3 Operation ............................................................................................................................................. 72
C.12.4 Measurement time interval ................................................................................................................ 72
C.13
Equipment category: Facsimile machines (telecopiers) and page scanners .............................. 73
C.13.1 Description .......................................................................................................................................... 73
C.13.2 Installation ........................................................................................................................................... 73
C.13.3 Operation ............................................................................................................................................. 74
C.13.4 Measurement time interval ................................................................................................................ 74
C.13.5 Reporting ............................................................................................................................................. 75
C.14
Equipment category: Cheque processors ....................................................................................... 76
C.14.1 Description .......................................................................................................................................... 76
C.14.2 Installation ........................................................................................................................................... 76
C.14.3 Operation ............................................................................................................................................. 76
C.14.4 Measurement time interval ................................................................................................................ 77
C.15
Equipment category: Personal computers and workstations ....................................................... 78
C.15.1 Description .......................................................................................................................................... 78
C.15.2 Installation ........................................................................................................................................... 78
C.15.3 Operation ............................................................................................................................................. 81
C.15.4 Measurement time interval ................................................................................................................ 82
C.16
Equipment category: Single-function printers printers (SFP) ....................................................... 83
C.16.1 Description .......................................................................................................................................... 83
C.16.2 Installation ........................................................................................................................................... 83
C.16.3 Operation ............................................................................................................................................. 83
C.16.4 Measurement time interval ................................................................................................................ 84
C.16.5 Reporting ............................................................................................................................................. 85
C.17
Equipment category: Self-service automatic teller machines ....................................................... 86
C.17.1 Description .......................................................................................................................................... 86
C.17.2 Installation ........................................................................................................................................... 86
C.17.3 Operation ............................................................................................................................................. 86
C.17.4 Measurement time interval ................................................................................................................ 86
C.18
Equipment category: Rack-mountable units and rack-enclosed systems ................................... 87
C.18.1 Description .......................................................................................................................................... 87
C.18.2 Installation ........................................................................................................................................... 87
C.18.3 Operation ............................................................................................................................................. 91
C.18.4 Measurement time interval ................................................................................................................ 92
C.18.5 Calculation of the system A-weighted sound power level and system A-weighted
emission sound pressure level from individual rack-mountable unit sound levels .................... 92
C.18.6 Calculation of A-weighted sound power level and A-weighted emission sound pressurelevel for low noise level rack-mountable units ................................................................................ 92
C.18.7 Reporting ............................................................................................................................................. 93
C.19
Equipment category: CD-and DVD-ROM drives .............................................................................. 94
C.19.1 Description .......................................................................................................................................... 94
C.19.2 Installation ........................................................................................................................................... 94
C.19.3 Operation ............................................................................................................................................. 94
C.19.4 Measurement time interval ................................................................................................................ 95
C.20
Equipment category: Data projectors............................................................................................... 96
C.20.1 Descriptions ........................................................................................................................................ 96
C.20.2 Installation ........................................................................................................................................... 96
C.20.3 Operation ............................................................................................................................................. 97
C.20.4 Measurement time interval ................................................................................................................ 97
C.21
Equipment category: Multi-function printers (MFP) ........................................................................ 98
C.21.1 Description .......................................................................................................................................... 98
C.21.2 Installation ........................................................................................................................................... 98
C.21.3 Operation ............................................................................................................................................. 98
C.21.4 Measurement time interval .............................................................................................................. 100

iv© Ecma International 2021

C.21.5 Reporting ............................................................................................................................................ 101
C.22
Equipment category: Hand-held computing and media playback devices ................................. 102
C.22.1 Description ......................................................................................................................................... 102
C.22.2 Installation .......................................................................................................................................... 102
C.22.3 Operation ............................................................................................................................................ 102
C.22.4 Measurement time interval ............................................................................................................... 102
C.23
Equipment category: Digital media recorders and playback units for consumer use .............. 103
C.23.1 Description ......................................................................................................................................... 103
C.23.2 Installation .......................................................................................................................................... 103
C.23.3 Operation ............................................................................................................................................ 103
C.23.4 Measurement time interval ............................................................................................................... 104
C.24
Equipment category- Large format printers (LFP) ......................................................................... 105
C.24.1 Description ......................................................................................................................................... 105
C.24.2 Installation .......................................................................................................................................... 105
C.24.3 Operation ............................................................................................................................................ 105
C.24.4 Measurement time interval ............................................................................................................... 106
C.24.5 Colour pattern scaling ...................................................................................................................... 107
C.24.6 Reporting ............................................................................................................................................ 107
Annex D (informative) Identification and evaluation of prominent discrete tones .................................. 109
D.1
Scope .................................................................................................................................................. 109
D.2
Information to be reported................................................................................................................ 109
Annex E (informative) Background information on the method formerly used for the detection of
impulsive noise .................................................................................................................................. 111
Annex F (informative) A hearing model approach to calculate psychoacoustic parameters ................. 113
Annex G (informative) Identification and evaluation of prominent tonalities using a
psychoacoustic tonality calculation method.................................................................................. 115
Annex H (informative) Identification and evaluation of prominent roughness using a
psychoacoustic roughness calculation method ............................................................................ 117© Ecma International 2021v

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© Ecma International 2021

Introduction
ECMA-74 specifies methods for the measurement of airborne noise emitted by information technology andtelecommunications equipment. Hitherto, a wide variety of methods have been applied by individual
manufacturers and users to satisfy particular equipment or application needs. These diverse practices have, inmany cases, made comparison of noise emission difficult. This Standard simplifies such comparisons and is
the basis for declaration of the noise emission level of information technology and telecommunications
equipment.
In order to ensure accuracy, validity and acceptability, this Standard is based on the basic Standards fordetermining the sound power level and for determining the emission sound pressure level at the operator
position(s) and bystander position(s). Furthermore, implementation is simplified by conformance with theseInternational Standards.
In many cases free-field conditions over a reflecting plane are realised by hemi-anechoic rooms. These rooms
may be particularly useful during product design to locate and to improve individual contributing noise sources.
Reverberation test rooms may be more economical for production control and for obtaining sound power levels
for noise emission declaration purposes.
The method for measuring the emission sound pressure level at the operator or bystander positions (based on
ISO 11201) is specified in a separate clause, as this level is not considered to be primary noise emission
declaration information. The measurements can, however, be carried out in conjunction with those for soundpower determination in a free field over a reflecting plane.
For comparison of similar equipment it is essential that the installation conditions and mode of operation are thesame. In Annex C these parameters are standardized for many categories of equipment.
The first edition of this Standard was issued in September 1981. It was contributed to ISO/TC 43 and formed
the base for ISO 7779:1988, first edition. The second edition of ECMA-74 was issued in December 1987. The
third edition was issued in December 1992 and was submitted to ISO for fast-track processing as a revision to
ISO 7779 in the spring of 1993. The document was balloted by ISO from November 1994 to May 1995 and wasapproved with 18 of 20 P members in favour and 2 of 22 member bodies opposed. The fourth edition was issued
in December 1996, taking into account most of the comments that accompanied the voting. The fifth edition was
issued December 1997 to add a new equipment category – CD- and DVD-ROM drives as C.19.
ISO 7779, second edition, was published August 1st, 1999. The sixth edition of ECMA-74 was adapted to thefinal wording of new ISO 7779 and also included additional provisions for CD- and DVD-ROM drives as C.19.
Now C.19 with minor modifications was adopted as ISO/DIS 7779 Amendment 1.
The C.19 changes that are in ISO/DIS 7779 Amendment 1 along with a revised Annex B and a revised Annex D
are included in the seventh edition of ECMA-74, which was approved in December, 2002. The Annex B includes
a provision allowing the use of a 0,5 m radius hemispherical surface for measuring the sound power emitted bysmall noise sources such as disk drives. Annex B also allows the use of a cylindrical measurement surface. The
revised Annex D in the seventh edition includes prominence ratio in addition to tone-to-noise ratio, provides
improved figures illustrating the tone-to-noise and prominence ratio calculations, and contains new criteria forprominent discrete tones. The new criteria are a result of a three-year study by Ecma TC26 and ITI TC6.
For the eighth edition, the reference list was updated and some text modified to account for the changes. The
cylindrical measurement surface section of Annex B was re-worded to more closely follow the wording used in
the draft of ISO 3744. Annex C contains additional figures in section C.15 on personal computers andworkstations. A new equipment category, C.20, for data projectors was added. Also Annex D was expandedwith additional figures, equations and examples.
For the ninth edition, only Annex D was modified. Changes were made in part to better define the critical bandedges, including changing from geometric critical bands to arithmetic critical bands for frequencies below 500 Hz.
Also, curves were fitted to the band edges for the lower and upper critical bands when calculating prominence
ratio, thus eliminating the need to use iteration for the calculations. Clarifications were added on frequency
range of interest and elsewhere. The criteria for prominence did not change.

© Ecma International 2021vii

For the 10th edition, changes were made to the main body of the Standard to be in agreement with upcomingchanges in the underlying standards: ISO 3741, ISO 3744, ISO 3745 and ISO 11201. Two new equipment
categories were added to Annex C: 1) multi-function devices (MFDs) and 2) hand-held computing and media
playback devices. The addition of these categories included some changes in the main body of the Standard
as well as some of the other print-related categories. Annex D was revised to give clearer direction on
determining the prominence of tones as well as introducing the concept of Threshold of Hearing when analyzing
very low-noise equipment.
For the 11th edition, changes were made to the Standard to align more closely with ISO 7779:2010, 3rd edition.
A new equipment category was added to Annex C, Digital media recorders and playback units for consumer
use. Also the document was reformatted with the new Ecma standards template.
For 12th edition, there were several updates as follows:
−
−
−
−

−

In Clause 3, the wording of some definitions was updated to be more consistent with the basic
standards (ISO 3741, ISO 3744, ISO 3745, ISO 11201).
In 7.3.1 and related sections, an expanded criteria on the environmental correction K2 was added toaddress its more detailed treatment in the basic standards.
In Annex B, the minimum number of fixed microphone positions on the cylindrical measurement
surface was made consistent with ISO 3744 Annex D.
In Annex C, the clarity and consistency of procedures for imaging equipment under C.3, C.13, C.16
and C.21 were improved. Inkjet printers were categorized under C.16. Procedures for measuring idle
mode noise were made uniform. The measurement of functional operations under C.13, C.16 andC.21 were aligned with one another and with the typical use prescription of C.1. The consistency ofmedia use and reporting procedures across C.13, C.16 and C.21 was improved. Hand-heldcomputing and media playback devices under C.22 having neither air moving devices nor a hard disk
drive were generally exempted from reporting requirements.
In Annex D, bibliographical references [40], [41] and [42] were replaced by ISO 28961 [9].

For 13th edition, there were several updates as follows:
−
−

−

−
−

In 6.4.6 and 7.4.6, the microphone calibration procedures were amended to be consistent to those of
the basic standards (ISO 3741 and 3744, respectively).
In 7.3.1, the procedure for test environment qualification was amended to clarify that any frequency
bands, typically low in frequency, not significantly affecting A-weighted sound power level need notmeet the hemi-anechoic room qualification criteria for the purposes of determining A-weighted soundpower level.
In Annex B, B.2, a procedure for reducing the microphone positions on cylindrical measurement
surface was introduced. This procedure is not presently in ISO 3744 but is expected in future versionsof ISO 3744. In addition, editorial improvements were made, and equations were renumbered.
In Annex D, some editorial improvements were made, and references to content within the annex
were corrected (no technical changes).
In Annex E, the method for detecting impulsive noise was removed. Because, by the recent update of
IEC 61672-1:2013, the time-weighting I, which was the technical basis of the previous detection
method in Annex E, had been removed. However, for historical reasons and also for the possibility of
future development of another method detecting for impulsive noise, this informative Annex E remains
with the same title, at least, in the 13th edition.

For 14th edition, there were several updates as follows:−

Annex C, C.21 Multi-function devices and its related categories were updated to harmonize theirgrammages and to refine MFD’s mandatory test conditions.

For 15th edition, there were several updates as follows:viii© Ecma International 2021

−

−
−

In Annex D descriptions were amended to clarify that Annex D permits using FFT data below 89,1 Hz
and above 11 200 Hz to calculate tone-to-noise ratio and prominence ratio. Notes were added toindicate that new metrics are under development for detecting prominent discrete tones for small fanswhose noise emissions consist of many harmonic components and other discrete tones.
A new Annex F was included on a hearing model approach to calculate psychoacoustic parameterssuch as prominent tonalities contained in the new Annex G and other psychoacoustic parameters.
A new Annex G was included on the identification and evaluation of prominent tonalities using a
psychoacoustic tonality calculation method, which is based on the hearing model approach in Annex
F. This method complements the procedures for determining prominent discrete tones contained in
Annex D.

For the 16th edition, changes were made to the Standard to align more closely with ISO 7779:2018, 4th edition[14].
In addition, Annex C was revised to add a new product category “Large Format Printers, and the productcategory “multi-function devices” (MFD) was renamed to “multi-function printers” (MFP). There were several
updates as follows:
−

−
−

−
−
−
−

−

In Clause 3, 3.1 General definitions and 3.2 Acoustical definitions were updated to be consistent withthose of International counterpart, ISO 7779 which relies on basic standards, such as ISO/TR 25417,
ISO 80000-8 etc., 3.3 Definitions related to uncertainty was newly added, corresponding to new
Clause 9.
In Clause 7, 7.3.1 was divided into 7.3.1.1 to 7.3.1.3, and amended to clarify that this Standard
permits applying either ISO 3744 or ISO 3745 for hemi-anechoic room qualification.
In Clause 8, 8.6, new 8.6.1 was inserted to clarify the method of defining operator position andbystander positions. And, references to new 8.6.2 (operator position) and new 8.6.3 (bystander
positions) were amended accordingly
In Clause 9, Measurement uncertainty was newly inserted.
In relation to Clause 9, 3.3 was also added, and the descriptions of Tables 1, 5 and 6 (in 6.2, 7.2 and8.2 respectively), and 10.2 were amended.
In Annex B, B.2.3 was amended to make the descriptions of measurement surface and the number ofmicrophone positions consistent with those of International counterpart, ISO 7779.
In Annex C, C.24 Large format printers was newly standardized, with related updates to C.1, C.16 andC.21. C.21 Multi-function devices (MFD) was renamed to “Multi-function printers (MFP)”, andmandatory mode of operation was revised, with related updates to C.1. Relating to the above,
distinctions between printing devices C.3, C.16, C.21 and C.24 were improved.
In Annex D, in D.9.7 and D.10.7, NOTES were amended to mention that new metrics proposed by
ECMA TR/108 for detecting prominent discrete tone, (1) total tone-to-noise ratio and (2) total
prominence ratio are under development.

For the 17th edition, there were several updates as follows:
−

−
−

−

The rounding of recorded sound pressure levels and sound power levels in 10.1.5 was changed to 0,1
dB deleting the option permitting rounding to 0,5 dB. A similar change was made for reported levels in
10.2.
Two definitions were added in Clause 3.2: Prominent Discrete Tones and Prominent Tonality.
Annex C, C.24 Large format printers was revised to clarify the definitions of professional printerswhich are excluded from scope of this category. And acceptable grammage of paper for graphics
applications was expanded to 200-300 g/m2.
Annex F, Modified outer and middle-/inner ear transfer function (Figure F.3, Table F.1) and the LTQ(Figure F.4, Table F.3) have been introduced in order to simulate the equal loudness contours
according to ISO 226-2003 for all frequencies. In the 15th edition, for frequencies above 1 kHz thesimulated equal loudness contours were matching the ISO 226-2003 values and for lower frequencies© Ecma International 2021ix

the ISO 226-1987 values. The newer data corresponds better to results of recent listening tests. The
filters used in the 15th edition lead to an overestimation of tonalities at frequencies below 500 Hz.
−

Annex G, Corrections of two mathematical formulations ((G.1) and (G.4)); constraints for searching
tonal components were removed (Formula (G.6) in 15th edition) to improve the algorithm, and somevariables were renamed for reasons of clarity.

For the 18th edition, there were several updates related to the creation of the psychoacoustic standards ECMA418-1 and ECMA-418-2, the introduction of new operating conditions for personal computers and workstations
in Annex C.15, and the introduction of operator positions for rack-mountable units and rack-enclosed systems
in Annex C.18:−

In Clause 3 the term operator was defined.

−

In 8.6.2, Figure 1 was divided into three figures by category: floor-standing equipment, table-top
equipment, and hand-held equipment.

−

Clause 10 was changed to require reporting of the maximum of the measured operator soundpressure levels when multiple operator positions are measured for rack-mountable units or rackenclosed systems.

−

New operating conditions for personal computers and workstations in Annex C.15.3. The modes ofoperation were designed to represent typical use of the whole system for the relevant segments. The
idle mode remains, and four (4) new operating conditions were defined. These are system level tests,
but a note is included with references to component level tests.”−

Table C.1 was altered to require measurement of sound pressure level at either operator or bystander
positions for rack-mountable units and rack-enclosed systems. Procedures for measuring andreporting sound pressure levels at operator positions for rack equipment were introduced in C.18.

−

In Annex C.18, figures were renumbered to accommodate new figures illustrating operator positions
for rack-mountable units and rack-enclosed systems. Figure C.5 of the 17th edition showing a print
test pattern was renamed as Figure C.8.

−

Annex D was reduced to a single page citing the new standard ECMA-418-1, Psychoacoustic metrics
for ITT equipment - Part 1 (prominent discrete tones). The technical content of Annex D in the 17thedition was moved to ECMA-418-1.

−

Annex F was reduced to a single page citing the hearing model content in the new standard ECMA418-2, Psychoacoustic metrics for ITT equipment - Part 2 (models based on human perception). The
hearing model content of Annex F in the 17th edition was moved to ECMA-418-2.

−

Annex G was reduced to a single page citing the prominent tonality content in the new standard
ECMA-418-2, Psychoacoustic metrics for ITT equipment - Part 2 (models based on humanperception). The prominent tonality content of Annex G in the 17th edition was moved to ECMA-418-2.

−

Annex H was introduced citing the roughness content in the new standard ECMA-418-2,
Psychoacoustic metrics for ITT equipment - Part 2 (models based on human perception).

For the 19 th edition, there were revisions related to Annex C.16. The title of C.16 was revised to “Singlefunction printers”, and the scope of C.16 was revised to allow equipment capable of printing rolled
stationery and to include inkjet and laser printers explicitly. Specifications were introduced for rolled
stationary grammage along with print pattern and print area for paper sizes smaller than A4.
This Ecma Standard was developed by Technical Committee 26 and was adopted by the General
Assembly of December 2021.

x© Ecma International 2021

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xi

xii

© Ecma International 2021

Measurement of Airborne Noise emitted by Information
Technology and Telecommunications Equipment

1

Scope

This Ecma Standard specifies procedures for measuring and reporting the noise emission of information
technology and telecommunications equipment.
NOTE 1This Standard is considered part of a noise test code (see 3.1.2) for this type of equipment, and is based on
basic noise emission standards (see 3.1.1) ISO 3741, ISO 3744, ISO 3745 and ISO 11201.

The basic emission quantity is the A-weighted sound power level which can be used for comparing equipmentof the same type but from different manufacturers, or for comparing different equipment.
Three basic noise emission standards for determination of the sound power levels are specified in this EcmaStandard in order to avoid undue restriction on existing facilities and experience. ISO 3741 specifies comparison
measurements in a reverberation test room; ISO 3744 and ISO 3745 specify measurements in an essentially
free field over a reflecting plane. Any one of these three basic noise emission standards can be selected andused exclusively in accordance with this Standard when determining sound power levels of a machine.
The A-weighted sound power level is supplemented by the A-weighted emission sound pressure level
determined at the operator position or the bystander positions, based on the basic noise emission standard
ISO 11201. This sound pressure level is not a worker's noise immission at a work station (see 3.2.12), but it can
assist in identifying any potential problems that could cause annoyance, activity interference or hearing damage
to operators and bystanders.
Method for determination of whether the noise emission includes prominent discrete tones is specified in
Annex D.
Annexes G and H reference psychoacoustic methods described in ECMA-418-2 on the identification andevaluation of prominent tonalities and prominent roughness generated by information technology andtelecommunications equipment
This Standard is suitable for type tests and provides methods for manufacturers and testing laboratories toobtain comparable results.
The methods specified in this Standard allow the determination of noise emission levels for a functional unit
(see 3.1.4) tested individually.
The procedures apply to equipment which emits broad-band noise, narrow-band noise and noise which contains
discrete-frequency components, or impulsive noise.
The sound power levels and emission sound pressure levels obtained can serve noise emission declarationand comparison purposes (see ECMA-109).
NOTE 2The sound power levels and emission sound pressure levels obtained are not intended to be considered as
installation noise immission levels; however they can be used for installation planning (see ECMA TR/27[16]).

If sound power levels obtained are determined for a number of functional units of the same production series,
they can be used to determine a statistical value for that production series (see ECMA-109).

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2

Normative references

The following referenced documents are indispensable for the application of this Standard. For dated references,
only the edition cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
ECMA-108 Determination of High-frequency Sound Power Levels Emitted by Information Technology and
Telecommunications Equipment
NOTE
ISO 9295[3] is ISO counterpart of ECMA-108. It is noted that, after the revision in 2015, the scope of ISO 9295
covers machinery and equipment in general, not limited to information technology and telecommunications equipment.

ECMA-418

Psychoacoustic metrics for ITT equipment - Part 1 (prominent discrete tones)

ECMA-418

Psychoacoustic metrics for ITT equipment - Part 2 (models based on human perception)

ISO 3741
Acoustics — Determination of sound power levels and sound energy levels of noise sources using
sound pressure — Precision methods for reverberation test rooms
ISO 3744
Acoustics — Determination of sound power levels and sound energy levels of noise sources using
sound pressure — Engineering methods for an essentially free field over a reflecting plane
ISO 3745
Acoustics — Determination of sound power levels and sound energy levels of noise sources using
sound pressure — Precision methods for anechoic test rooms and hemi-anechoic test rooms
ISO 6926
Acoustics — Requirements for the performance and calibration of reference sound sources used
for the determination of sound power levels
ISO 10302-1 Acoustics — Method for the measurement of airborne noise emitted and structure-borne vibrationinduced by small air-moving devices — Part 1: Airborne noise measurement
ISO 10302-2 Acoustics — Method for the measurement of airborne noise emitted and structure-borne vibrationinduced by small air-moving devices — Part 2: Structureborne vibration measurement
ISO 11201 Acoustics — Noise emitted by machinery and equipment — Determination of emission soundpressure levels at a work station and at other specified positions in an essentially free field over a reflecting
plane with negligible environmental corrections
ISO 11203 Acoustics — Noise emitted by machinery and equipment — Determination of emission soundpressure levels at a work station and at other specified positions from the sound power level
IEC 60942

Electroacoustics — Sound calibrators

IEC 61183

Electroacoustics — Random-incidence and diffuse-field calibration of sound level meters

IEC 61260-1 Electroacoustics — Octave-band and fractional-octave-band filters — Part 1: Specifications
IEC 61672-1 Electroacoustics — Sound level meters — Part 1: Specifications
ISO/IEC 10561:1999 Information technology — Office equipment — Printing devices — Method for measuring
throughput — Class 1 and Class 2 printers
NOTE 1

C.3 refers to ISO/IEC 10561:1999.

ISO/IEC 11160-1:1996
Information technology — Office equipment — Minimum information to be includedin specification sheets — Printers — Part 1: Class 1 and Class 2 printers
NOTE 22

C.3 refers to ISO/IEC 11160-1:1996.

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3

Terms and definitions

For the purposes of this Ecma Standard, the terms and definitions given in ISO 3744, and ISO 11201, and thefollowing apply.
NOTE

If a definition is identical to that in another standard, that standard and definition number is given in brackets.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:—

ISO Online browsing platform: available at https://www.iso.org/obp—

IEC Electropedia: available at http://www.electropedia.org/

3.1

General definitions

3.1.1
basic noise emission standard
B-type standard
standard which specifies a procedure for determining the noise emission of machinery and equipment in sucha way as to obtain reliable, reproducible results with a degree of accuracy[SOURCE: ISO 12001:1996[8], 3.1]
3.1.2
noise test code
C-type standard
standard that is applicable to a particular class, family or type of machinery or equipment which specifies all theinformation necessary to carry out efficiently the determination, declaration and verification of the noise emission
characteristics under standardized conditions[SOURCE: ISO 12001:1996[8], 3.2, modified — NOTE 1 to entry was added.]
NOTE
This Standard (ECMA-74) together with ECMA-109[15] comprises the noise test code for ITT Equipment. These
Standards are Ecma counterparts of ISO 7779[14] and ISO 9296[4], respectively. Both set of noise test codes (Ecma andISO) are consistent with guidelines specified in ISO 12001.

3.1.3
information technology and telecommunications equipment
ITT equipment
equipment for information processing, and components thereof, used in homes, offices, server installations,telecommunications installations, or similar environments
NOTE
Annex C, which specifies particular requirements for use with this Standard, may be useful in identifying manyof the categories of ITT equipment.

3.1.4
functional unit
unit of information technology and telecommunications equipment, either with or without its own end-use
enclosure, that is tested or intended to be tested according to the procedures of this Standard
NOTE 1
A functional unit can comprise more than one unit of ITT equipment when such units are to be tested together
in accordance with the methods of this Standard. A functional unit can also comprise one or more units of ITT equipment
coupled to one or more units of non-ITT equipment, such as power modules, water pumps, or refrigeration units, when such
equipment is necessary for the normal operation of the ITT equipment.
NOTE 2Functional units of ITT equipment can take on a wide range of forms, including commercially-available products,
prototype units under development, or sub-assemblies and components thereof.

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3.1.5work station
operator's position
position in the vicinity of the equipment under test which is intended for the operator
NOTE 1

Adapted from ISO 11201:2010, 3.11.

NOTE 2This term does not refer to a computer “workstation”, which denotes a high-performance, single-user computer.

3.1.6
operator
individual whose work station is in the vicinity of equipment and who is performing a work task associated withthat equipment
NOTE

Adapted from ISO 11201:2010, 3.12.

3.1.7
operating modecondition in which the equipment being tested is performing its intended function(s)3.1.8
idle mode
one or more steady-state conditions in which the equipment being tested is energized but is not operating
3.1.9
floor-standing equipment
functional unit which is intended to be installed on the floor
3.1.10table-top equipment
functional unit which has a complete enclosure and which is intended to be installed or used on a table, desk or
separate stand3.1.11wall-mounted equipment
functional unit which is normally mounted against or in a wall and which does not have a stand of its own
3.1.12sub-assembly
functional unit, generally without its own end-use enclosure, intended to be installed in another unit of ITT
equipment or assembled together with other sub-assemblies or units of ITT equipment into a single end-use
enclosure
3.1.13rack-mountable unit
functional unit that is designed to be installed in an end-use enclosure in the form of a rack, frame, or cabinet,
either fully-enclosed, partially-enclosed, or open-frame
3.1.14rack-enclosed system
functional unit in the form of a rack, frame, or cabinet containing one or more rack-mountable units
NOTE
Rack-enclosed systems represent a wide variety of ITT equipment, depending on the particular configuration of
the rack-mountable units in the rack or enclosure. These can be server systems, storage systems, I/O systems, networking
systems, or “integrated” systems of these or other types of rack-mountable units.

3.1.15hand-held equipment
functional unit, generally small and lightweight, intended to be supported in one’s hand(s) during operation

4© Ecma International 2021

3.1.16
standard test table
rigid table having a top surface of at least 0,5 m2 and length of the top plane not less than 700 mm
NOTE

3.2

The design for the standard test table is shown in A.1.

Acoustical definitions

3.2.1
emissionnoise emission
airborne sound radiated by a well-defined noise source (e.g. the equipment under test)
NOTE
Noise emission descriptors can be incorporated into a product declaration and/or product specification. The
basic noise emission descriptors are the sound power level of the source itself and the emission sound pressure levels at
an operator position (work station) and/or at bystander positions (if no operator position is defined) in the vicinity of thesource.

3.2.2
sound pressurepdifference between instantaneous total pressure and static pressure
NOTE 1

Sound pressure is expressed in pascals.

NOTE 2The symbol p for instantaneous sound pressure, is often used without modification to represent a root-meansquare (RMS) sound pressure.
NOTE 3

See ISO 80000-8:2007[10], 9.2.

3.2.3
sound pressure level,Lp
ten times the logarithm to the base 10 of the ratio of the square of the sound pressure, p, to the square of areference value, p0
L p = 10lg

p2
p 02

dB

NOTE 1

Sound pressure level, Lp, is expressed in decibels with a reference value, p0, of 20 µPa (20 × 10-6 Pa).

NOTE 2This definition is technically in accordance with ISO 80000-8:2007[10], 8.22.

[ISO/TR 25417:2007[11], 2.2, modified — NOTES to entry were removed.]
3.2.4
time-averaged sound pressure level
Lp,T
ten times the logarithm to the base 10 of the ratio of the time average of the square of the sound pressure, p,during a stated time interval of duration, T (starting at t1 and ending at t2), to the square of a reference value, p0,
expressed in decibels

 1 t2p 2 ( t ) dt 
T

t
 dB
L p ,T = 10 lg  1
2


p0









© Ecma International 20215

where the reference value, p0, is 20 μPa
NOTE 1
Because of practical limitations of the measuring instruments, p2 is always understood to denote the square ofa frequency-weighted and frequency-band-limited sound pressure. If a specific frequency weighting as specified in
IEC 61672-1 and/or specific frequency bands are applied, this should be indicated by appropriate subscripts; e.g. Lp,A,10 sdenotes the A-weighted time-averaged sound pressure level over 10 s.
NOTE 2
Lp,T can be interpreted as the sound pressure level of a stable and permanent noise that will have the same
average energy as the noise under study.

3.2.5
emission sound pressure levelLpsound pressure level at a specified position near a machine, when the machine is in operation under specified
operating and mounting conditions on a reflecting plane surface, but excluding the effects of background noise
as well as the effect of reflections other than those from the plane or planes permitted for the purpose of the
test
NOTE 1The emission sound pressure level is expressed in decibels with a reference value, p0, of 20 µPa (20 × 10-6 Pa).

NOTE 2Clause 8 specifies the method for determination of emission sound pressure level.

[SOURCE: ISO 11205:2003[6], 3.6, modified — NOTE 1 to entry was elaborated and NOTE 2 to entry wasadded.]
3.2.6
time-averaged emission sound pressure level
LpeqT
emission sound pressure level of a continuous steady sound that, within a measurement time interval, T, has
the same mean-square sound pressure as a sound under consideration which varies with timeT

L peqT = 10lg

p 2 (t ) p 02 dt dB
0

NOTE 1
The time-averaged emission sound pressure level is expressed in decibels with a reference value, p0, of 20 µPa(20 × 10-6 Pa).
NOTE 2The emission sound pressure level is determined at the specified position(s) required by the noise test code (i.e.
this Standard, for specific families of ITT equipment).
NOTE 3
Clause 8 of this Standard specifies the method for the determination of time-averaged A-weighted emission
sound pressure level, LpA, for ITT equipment defined in 3.1.3.
NOTE 4
In general, the subscripts “eq” and “T” are omitted since time-averaged emission sound pressure levels arenecessarily determined over a certain measurement time interval.

3.2.7
C-weighted peak emission sound pressure level
LpCpeakhighest instantaneous value of the C-weighted emission sound pressure level determined over an operational
cycle
NOTE
10-6 Pa).

6

The C-weighted peak sound pressure level is expressed in decibels with a reference value, p0, of 20 µPa (20 ×© Ecma International 2021

3.2.8sound powerPthrough a surface, product of the sound pressure, p, and the component of the particle velocity, un, at a point on
the surface in the direction normal to the surface, integrated over that surface
NOTE 1

Sound power is expressed in watts.

NOTE 2The symbol, P, is often used without modification for the mean value (over time) of the sound power.

NOTE 3The quantity relates to the rate per unit time at which airborne sound energy is radiated by a source.

[SOURCE: ISO/TR 25417:2007[11], 2.8]
3.2.9
sound power level
LW
ten times the logarithm to the base 10 of the ratio of the sound power, P, radiated by the sound source under
test to the reference value, P0
LW = 10 lg

P
dB
P0

NOTE 1

Sound power level LW is expressed in decibels with a reference value of 1 pW (10-12 W).

NOTE 2Clauses 6 and 7 of this standard specify the method for the determination of the A-weighted sound power level,
LWA, for ITT equipment defined in 3.1.3.

[SOURCE: ISO/TR 25417:2007[11], 2.9, modified — NOTE 2 to entry was added.]
3.2.10reference sound source
device which is intended for use as a stable source of sound, which has a known, broad-band sound power
spectrum determined in full conformance with ISO 6926 over the frequency range of interest.
3.2.11
frequency range of interest
range of one-third-octave bands with centre frequencies from 100 Hz to 10 000 Hz inclusive
NOTE
For equipment which emits discrete tone(s) in the 16 kHz octave band, the procedures specified in ECMA-108
are used; see Table 4.

3.2.12noise immission at a work station
any noise that arrives, whether or not a worker is present, over a specific time period T, at a measuring point(work station) in the actual situation; i.e. noise coming from the machine, noise coming from the other soundsources and noise reflected by the ceiling, the walls and any fittings[SOURCE: ISO 11690-1:1996[7], 3.3.1, modified — NOTE 1 to entry and the reference to Figure 1b) weredeleted.]3.2.13prominent discrete tone
a discrete tone is one of many causes of tonality, Annex D describes two methods to evaluate whether prominent
discrete tones are contained in a measurement.

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3.2.14
prominent tonality
tonality arises from discrete tones, elevated or sloped noise spectra, and conjunctions of these phenomena.
Annex G describes a psychoacoustic method to evaluate the prominence of these sources of tonality (including
discrete tones) based on the hearing model in Annex F.

3.3

Definitions related to uncertainty

3.3.1
standard deviation of repeatability
σrstandard deviation of noise emission values obtained under repeatability conditions, that is the repeatedapplication of the same noise emission measurement method on the same noise source within a short intervalof time under the same conditions (same laboratory, same operator, same apparatus)[SOURCE: ISO 7574-1:1985[2], 3.16]
3.3.2
standard deviation of reproducibility
σR0standard deviation of noise emission values obtained under reproducibility conditions, that is the repeatedapplication of the same noise emission measurement method on the same noise source at different times andunder different conditions (different laboratory, different operator, different apparatus)
NOTE 1The standard deviation of reproducibility, therefore, includes the standard deviation of repeatability (see 3.3.1).

NOTE 2
An estimate of σR0 to be given in the measurement test code for the family of machines should preferably bederived from an interlaboratory test. In the absence of such a test, σR0 may be agreed upon provisionally.

[SOURCE: ISO 7574-1:1985[2], 3.17, modified — The last part of the definition was moved to a new NOTE 1 toentry and NOTE 1 to entry was renumbered as NOTE 2 to entry.]
3.3.3
round robin testing
testing of identical materials at different test facilities for the comparison of results[SOURCE: ISO 14624-3:2005[34], 3.7]
3.3.4
overage factor
knumerical factor used as a multiplier of the combined standard uncertainty in order to obtain an expanded
uncertainty
NOTE

A coverage factor is typically in the range from 2 to 3.

[SOURCE: ISO/IEC Guide 98-3:2008[13]]4

Conformity requirements

Measurements are in conformity with this Standard if they meet the following requirements:a) the measurement procedures, the installation and the operating conditions specified by this Standard
shall be taken fully into account.
b) for the determination of sound power levels, one (and only one) of the methods specified in Clause 6
or Clause 7 is shall be used.

8© Ecma International 2021

c) for the determination of emission sound pressure level at the operator or bystander positions, themethod specified in Clause 8 shall be used.

5

Installation and operating conditions

5.1

Equipment installation

5.1.1

GeneralThe equipment shall be installed in accordance with its intended use. Requirements are given in this clause forgeneral types of equipment. Specific installation conditions for many different categories of ITT equipment are
specified in Annex C, and these shall be followed insofar as they represent the intended use of the equipment.
If the normal installation associated with intended use is unknown or ambiguous or if several possibilities exist,
a representative condition shall be selected for the measurements and reported.
Care shall be taken to ensure that any electrical conduits, piping, air ducts or other auxiliary equipment
connected to the equipment being tested do not radiate significant amounts of sound energy into the test room.
If practicable, all auxiliary equipment necessary for the operation of the equipment shall be located outside thetest room and the test room shall be free from all objects which can interfere with the measurements.
NOTE
If the equipment is mounted near one or more reflecting planes, the sound power radiated by the equipment
can depend upon its position and orientation. It is possible that the determination of the radiated sound power is of interest
either for one particular equipment position and orientation or from the average value for several positions and orientations.

5.1.2
5.1.2.1

Floor-standing equipment
Requirements for reverberation test rooms

Floor-standing equipment (see 3.1.9) shall be located at least 1,5 m from any wall of the room and no major
surfaces shall be parallel to a wall of the reverberation test room.
5.1.2.2

Requirements for hemi-anechoic rooms

Floor-standing equipment (see 3.1.9) shall be installed on the reflecting (hard) floor at a sufficient distance (morethan 2 m, if possible) from the walls, unless otherwise specified in Annex C.
The equipment shall be installed in a way which allows access to all sides except the reflecting plane(s). The
dimensions of the reflecting plane(s) shall extend beyond the test object by at least the measurement distance.
Information on reflection is given in 7.3.1.1, NOTE 1. The plane(s) shall not contribute to the sound radiation
due to their own vibrations.
5.1.2.3

Common requirements

If the equipment being tested consists of several frames bolted together in an installation or is too large fortesting purposes, the frames may be measured separately. In such circumstances, additional covers can berequired for the frames during the acoustical evaluation. These additional covers shall be acousticallycomparable with the other covers on the equipment. If a unit is mechanically or acoustically coupled to anotherunit so that the noise emission levels of one are significantly influenced by the other, the equipment being tested
shall, where practicable, include all units coupled together in this way.
Floor-standing equipment which is to be installed only in front of a wall shall be placed on a hard floor in front ofa hard wall (information on reflection are given in 7.3.1.1, NOTE 1). The distance from the wall shall be inaccordance with the manufacturer's instructions or as specified in Annex C. If such information is not available
there, the distance shall be 0,1 m.

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5.1.35.1.3.1

Table-top equipment
Requirements for reverberation test rooms

Table-top equipment (see 3.1.10) shall be placed on the floor at least 1,5 m from any wall of the room unless atable or stand is required for operation in accordance with Annex C (e.g. printers which take paper from or stack
paper on the floor). Such equipment shall be placed in the centre of the top plane of the standard test table inaccordance with A.1.
5.1.3.2

Requirements for hemi-anechoic rooms

Table-top equipment (see 3.1.10) shall be placed on the floor, unless a table or stand is required for operationin accordance with Annex C (e.g. printers which take paper from or stack paper on the floor). Such equipment
shall be placed in the centre of the top plane of the standard test table in accordance with A.1. In any case themeasurement surface defined in 7.6 terminates on the floor.
5.1.4

Wall-mounted equipment

Wall-mounted equipment (see 3.1.11) shall be affixed to a wall of the reverberation test room at least 1,5 mfrom any other reflecting surface, unless otherwise specified. Alternatively, if operation permits, the equipment
may be laid with its mounting surface on the floor at least 1,5 m (more than 2 m, if possible, in hemi-anechoic
rooms) from any wall of the room.
If the equipment is usually installed by being recessed into a wall or other structure, a representative structure
shall be used for mounting during the measurements and described in the test report.
5.1.5

Rack-mounted equipment

Rack-mounted equipment includes both individual rack-mountable units (see 3.1.13) and rack-enclosed
systems (see 3.1.14). Rack-mountable units shall either be tested outside of the rack or installed in a rack
enclosure in accordance with the requirements of C.18.2. Rack-enclosed systems shall be tested either as floorstanding equipment (see 5.1.2) or as table-top equipment (see 5.1.3) in accordance with the type and size ofsystem. The specific installation and operation requirements of C.18.2 and C.18.3, respectively, shall befollowed.
For rack-enclosed systems that are available in more than one configuration of rack-mountable units, theparticular configuration to be measured is usually governed by the purposes of the test and is thus not specified
in this Standard (see C.18.1 for more information).
5.1.6

Hand-held equipment

Hand-held equipment (see 3.1.15) shall be supported 0,25 m ± 0,03 m above the reflecting plane by a vibrationisolating stand or fixture, or by appropriate vibration-isolating elements. If a hemispherical measurement surface
is used with any radius less than 1 m (see B.1), the hand-held equipment support height shall be reduced to
0,125 m ± 0,015 m. The method of supporting the hand-held equipment shall not interfere with the propagationof airborne sound from the equipment or generate any additional sound radiation.
5.1.7

Sub-assemblies

A sub-assembly (see 3.1.12) shall be supported 0,25 m ± 0,03 m above the reflecting plane by a vibrationisolating stand or fixture, or by appropriate vibration-isolating elements. If a hemispherical measurement surface
is used with any radius less than 1 m (see B.1), the sub-assembly support height shall be reduced to 0,125 m± 0,015 m. The method of supporting the sub-assembly shall not interfere with the propagation of airborne soundfrom the sub-assembly or generate any additional sound radiation.
If the above-specified support height is not adequate to allow the manufacturer’s recommended air flow at the
sub-assembly’s air inlet, the height may be adjusted accordingly but shall not exceed 0,5 m. The new height
shall be documented in the test report.

10© Ecma International 2021

5.2

Input voltage and frequency

The equipment shall be operated at its nominal rated voltage and the rated power line frequency.
Phase-to-phase voltage variations shall not exceed 5 %.

5.3

Equipment operation

During the acoustical measurements the equipment shall be operated in a manner typical of normal use.
Annex C specifies such conditions for many categories of equipment and shall be followed. However, if thespecified conditions are clearly contrary to the objective of providing uniform conditions closely corresponding
to the intended use of the product, then an additional mode or modes closely related to the intended use shallbe defined, tested and described in the test report. Any subsequent declaration shall either:−declare both values, indicating that one is based on Annex C and that the other is declared by the
manufacture to be typical use for intended application; or−

declare only the latter, indicating that it is not based on Annex C but is declared by the manufacturer to be
typical use for intended application.

When there are multiple operating modes specified in Annex C, at a minimum, the most typical operating modeshall be chosen for the measurement. This mode shall be clearly described in the test report.
The equipment shall be operated for a sufficient period of time before proceeding with the acoustical test toallow temperature and other pertinent conditions to stabilize.
The noise shall be measured with the equipment in both the idle and operating modes. If the equipment isdesigned to perform different functions, such as manual typing and automatic printing of stored information, orfor printing in different print qualities, unless otherwise specified in Annex C, the noise of each individual modeshall be determined and recorded. For equipment which, in normal functional operation, performs several
operating modes, such as document insertion, reading, encoding, printing and document eject, and for which atypical operation cycle has not been defined in Annex C, such a typical cycle shall be defined for themeasurements. This mode shall be clearly described in the test report.
For rack-mounted equipment in which the operation of several functional units is possible, the units intended tooperate together shall do so during the test; all other units shall be in idle mode. In the absence of operational
specifications provided by Annex C or by the manufacturer, an operating mode that represents the most typicalusage shall be defined and tested. This mode shall be clearly described in the test report.
Some equipment does not operate continuously because of its mechanical design or its mode of operation
under program control. Long periods can occur during which the equipment is idle. The operating modemeasurements shall not include these idle periods. If it is not possible to operate the equipment continuously
during the acoustical evaluation, the time interval during which measurements have to be made shall be definedand clearly described in the test plan, equipment specifications or other documentation.
Some equipment has operational cycles that are too short to allow reliable determination of the noise emissions.
In such cases, a typical cycle shall be repeated several times.
If the equipment being tested produces attention signals, such as tones or bells, such intermittent sound shallnot be included in an operating mode. During the acoustical evaluation in the operating mode(s), such attention
signals shall be inoperative or, if this is not possible, they shall be set to a minimum.
NOTE
For certain applications, such signals as well as the maximum response of feedback signals of keyboards canbe of interest. Such measurements can be made, but they are not part of the methods specified in this Standard.

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6
Method for determination of sound power levels of equipment in reverberation
test rooms
6.1

GeneralThe method specified in this clause provides a comparison procedure for determination of the sound power
levels of ITT equipment in a reverberation test room, in accordance with the comparison method specified in
ISO 3741. It applies to equipment which radiates broad-band noise, narrow-band noise, noise which contains
discrete frequency components or impulsive noise.
It is strongly recommended that the room be qualified for discrete-frequency components in accordance withthe relevant procedure specified in ISO 3741. This avoids the need to determine the number of microphone
positions and equipment locations each time equipment is measured.

6.2

Measurement uncertainty

Measurements carried out in accordance with this method yield standard deviations of reproducibility for thefrequency range of interest of this Standard which are equal to, or less than, those given in Table 1.
Table 1 — Typical upper bound values of the standard deviation of reproducibility in determining
sound power levels in a reverberation test room in accordance with Clause 6
Octave band
centre frequencies

One-third-octave band
centre frequencies

Standard deviation of
reproducibility, σR0

Hz

Hz

dB

125

100 to 160

3,0

250

200 to 315

2,0500 to 4 000

400 to 5 000

1,5

8 000

6 300 to 10 000

3,0NOTE 1
For most ITT equipment, the A-weighted sound power level is determined by the sound power levels in the
250 Hz to 4 000 Hz octave bands. The A-weighted sound power level is determined with a standard deviation of
approximately 1,5 dB. A larger standard deviation can result when the sound power levels in other bands determine theA-weighted sound power level.
NOTE 2The standard deviations of reproducibility, σR0 (see 3.3.2), given in Table 1, reflect the cumulative effects of allcauses of measurement uncertainty, including variations from laboratory to laboratory, but excluding variations in the soundpower level from equipment to equipment or from test to test which can be caused, for example, by changes in the installation
or operating conditions of the equipment. In quantitative sense, the repeatability, σr (see 3.3.1), of the test results for thesame piece of equipment and the same measurement conditions can be considerably better (i.e. smaller standard
deviations) than indicated by the values given in Table 1.
NOTE 3
If the method specified in this clause is used to compare the sound power levels of similar equipment that areomnidirectional and radiate broad-band noise, this comparison yields a standard deviation which is less than that given in
Table 1, provided that the measurements are carried out in the same environment.

6.3
6.3.1

Test environment
General

Guidelines specified in ISO 3741 for the design of the reverberation test room, as applicable, shall be used.
Criteria for room absorption and the procedure for room qualifications, specified in ISO 3741 shall be used.
ISO 3741 shall be followed with regard to the following:

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a) test room volume;b) level of background noise.
6.3.2

Meteorological conditions

The requirements of ISO 3741 shall be followed.
The following conditions are recommended:a)ambient pressure: 86 kPa to 106 kPa;b)temperature: within the range defined by the manufacturer for the equipment, if a range is defined; if norange is so defined by the manufacturer, the recommended range is 15 °C to 30 °C;c)relative humidity: within the range defined by the manufacturer for the equipment, if a range is defined; forprocessing of paper and card media only, if no range is so defined by the manufacturer, the recommended
range is 40 % to 70 %.

For equipment whose noise emissions vary with ambient temperature in a prescribed manner (e.g. by varying
the speeds of air-moving devices), the room temperature during the measurement shall be 23 C  2 C.
For equipment whose noise emissions vary with altitude in a prescribed manner (e.g. by varying the speeds of
air-moving devices), either the altitude of the test room shall either be less than or equal to 500 m, or theequipment shall be tested under conditions simulating its operation at an altitude less than or equal to 500 m.
NOTEThis variation of speed of air-moving devices does not refer to the changing speed that is already accounted forin the correction for ambient pressure described in 6.10.1, NOTE.

6.4
6.4.1

Instrumentation
GeneralThe requirements of this subclause (6.4), as well as the instrumentation requirements of ISO 3741, shall befollowed.
Digital integration is the preferred method of averaging.
6.4.2

The microphone and its associated cable

The instrument system, including the microphone and its associated cable, shall meet the requirements of
ISO 3741. If the microphone is moved, care shall be exercised to avoid introducing acoustical or electrical noise(e.g. from gears, flexing cables, or sliding contacts) that could interfere with the measurements.
6.4.3

Frequency response of the instrumentation system

The requirements of ISO 3741 shall be followed.
6.4.4

Reference sound source

The reference sound source shall meet the requirements specified in ISO 6926 over the frequency range ofinterest.
6.4.5

Filter characteristics

The requirements for an instrument specified in accordance with IEC 61260, class 1 shall be followed.

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6.4.6

Calibration

The microphones shall be calibrated for random incidence as specified in IEC 61183.
Before and after each series of measurements, a sound calibrator meeting the requirements of
IEC 60942, class 1 shall be applied to each microphone to verify the calibration of the entire measuring system
at one or more frequencies within the frequency range of interest. Without any further adjustment, the difference
between the readings made before and after each series of measurements shall be less than or equal to 0,5 dB.
If this value is exceeded, the results of the series of measurements shall be discarded.
NOTE
A “series” of measurements does not require that this verification be conducted “daily”. Other methods forchecking the calibration of the measurement system to insure this requirement will be met can be available. For example,
see JBMIA-TR-28[18].

The calibration of the sound calibrator, the compliance of the instrumentation system with the requirements of
IEC 61672-1, the compliance of the filter set with the requirements of IEC 61260-1 and, if used, the complianceof the reference sound source with the requirements of ISO 6926 shall be verified at intervals in a laboratory
making calibrations traceable to appropriate standards preferably by meeting the requirements of
ISO/IEC 17025[12].
The sound calibrator should be calibrated at intervals not exceeding 1 year, the reference sound source should
be calibrated at intervals not exceeding 2 years, the compliance of the instrumentation system with therequirements of IEC 61672-1 should be verified at intervals not exceeding 2 years, and the compliance of thefilter set with the requirements of IEC 61260-1 should be verified at intervals not exceeding 2 years.

6.5

Installation and operation of equipment: General requirements

See Clause 5.

6.6
6.6.1

Microphone positions and source locations
GeneralThe major cause of uncertainty in determining sound power level in a reverberation test room is the spatial
irregularity of the sound field. The extent of this irregularity and, hence, the effort required to determine the timeaveraged sound pressure level accurately are greater for discrete-frequency sound than for broad-band sound.
It is strongly recommended that the room be qualified for the measurement of discrete-frequency components
in accordance with the relevant procedures of ISO 3741. This avoids the need to determine the number ofmicrophone positions and equipment locations each time equipment is measured.
If the room has not been qualified for the measurement of discrete-frequency components, the procedures
specified in ISO 3741 shall be used to determine the minimum number of microphone positions and to evaluate
the need for additional noise source locations prior to each measurement. The results of these procedures
depend on the presence or absence of significant discrete-frequency components or narrow bands of noise in
the sound emitted by the source. When these are present, the number of microphone positions and equipment
locations may be large.
6.6.2

Number of microphone positions, reference sound source locations and equipment locations

The requirements of ISO 3741shall be followed.

6.6.3

Microphone arrangement

The requirements of ISO 3741shall be followed.

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6.7
6.7.1

Measurement of sound pressure level
GeneralThe requirements of ISO 3741 shall be followed, as applicable.
NOTE
Depending on the purposes of the test, it may be the case that one or more repeated measurements are taken
for either the sound pressure levels of the reference sound source (see 6.8) or the source under test (see 6.9), or both.
Provided that each of the measurements in the repeated set represent identical conditions for the reference sound sourceor the source under test, and that they are each valid measurements in accordance with the requirements of this Standard,
the arithmetic average of the measured sound pressure levels, in decibels, should be taken as the measurement result fromthis clause.

6.7.2

Measurement time interval

The requirements below in addition to those of ISO 3741 shall be followed, as applicable.
For equipment which performs repetitive operation cycles (e.g. enveloping machines), the measurement timeinterval shall include at least three operation cycles. For equipment which performs a sequence of varying
operation cycles, the measurement time interval shall include the total sequence. Annex C specifies additional
requirements for many categories of equipment.
6.7.3

Corrections for background noise

The requirements of ISO 3741 shall be followed, as applicable.
NOTE
When the background noise levels in the test room are extremely low and very controlled, it is possible that theenvironment satisfies the absolute and/or relative criteria for background noise in accordance with ISO 3741.

6.8

Measurement of the sound pressure level of the reference sound source

The requirements below in addition to those of ISO 3741 shall be followed.
For the purposes of determining the sound power level of the equipment by means of reverberation test rooms,
this Standard uses exclusively the comparison method specified in ISO 3741. This method has the advantagethat it is not necessary to measure the reverberation time of the test room. The comparison method requires
the use of a reference sound source with characteristics and calibration in accordance with ISO 6926 and forwhich the sound power levels have been determined in full conformance with ISO 6926 over the frequency
range of interest (see 3.2.12). The reference sound source shall be operated, as described in its calibration
chart, in the presence of the equipment being tested and in the presence of the operator, if required to operate
the equipment.

6.9

Calculation of the mean time-averaged band sound pressure levels

The requirements of ISO 3741 shall be followed.

6.10
6.10.1

Determination of sound power level
Calculation of band sound power levels

The sound power level, under reference meteorological conditions, of the equipment in each one-third-octave
band within the frequency range of interest (see 3.2.11) is obtained by using the comparison method of ISO
3741.
NOTE
The procedures in ISO 3741 are used to determine the sound power level under reference meteorologicalconditions (ambient pressure 1,013 25 × 105 Pa, temperature 23,0 °C, relative humidity 50 %).

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The sound power level in the k-th octave band, LWoct, k in decibels, if needed, shall be based on one-third-octave
band data, and calculated from:3k

LW oct,k = 10lg

 100,1LW 1/ 3, j

j =3 k − 2

dB

(1)

where
k

is an identification number of octave band within the frequency range of interest (see Table 2);

LW1/3, jis the sound power level in the j-th one-third-octave band, in decibels (see Table 3);j
is an identification number lying within the range of (3k – 2) and 3k, which identifies the three one-thirdoctave bands which make up the k-th octave band.
6.10.2

Calculation of A-weighted sound power level

The A-weighted sound power level, LWA in decibels shall be based on the frequency range of interest, andcalculated as per Formula (2):21

LW A = 10lg

10
j =1

(

0,1 LW 1/ 3, j + A j

)

dB

(2)

where

NOTE
Clause 7.

LW1/3, jis the sound power level, in decibels, in the j-th one-third-octave band;

Aj

is the A-weighting value corresponding to the j-th one-third-octave band (see Table 3);j

is an identification number of a one-third-octave band within the frequency range of interest(see Table 3).
Formulae (1) and (2), as well as Tables 2 and 3, are intended for common use for not only Clause 6, but also

Table 2 — Identification number, k for octave bandsk

Octave-band centre frequency
Hz

16

1

125

2

250

3

500

4

1 000

5

2 000

6

4 000

7

8 000

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Table 3 — Values of A-weighting, Aj, for one-third-octave bands
One-third-octave-band
centre frequency

A-weighting
Aj

Hz

dB

1

100

– 19,1

2

125– 16,1

3160– 13,44200– 10,9

5

250

– 8,6

6

315

– 6,6

7

400

– 4,8

8

500

– 3,2

9

630

– 1,9

10

800

– 0,8

11

1 000

0,0

12

1 250

0,6

13

1 600

1,0

14

2 000

1,2

15

2 500

1,3

16

3 150

1,2

17

4 000

1,0

18

5 000

0,5

19

6 300

– 0,1

20

8 000

– 1,1

21

10 000– 2,5jSome ITT equipment emits high-frequency noise in the 16 kHz octave band. Depending upon the nature ofnoise emissions, Table 4 shows how to handle each situation.
For the determination of A-weighted sound power levels from band levels, this Standard does not extend thefrequency range of interest to include the 16 kHz octave band.

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For equipment which emits discrete tone(s) in the 16 kHz octave band, each frequency and level of the tone(s)that is (are) within 10 dB of the highest tone level in the band shall be determined in accordance with theprocedures specified in ECMA-108 (see Table 4). The derived levels are not frequency weighted.
CAUTION

The 16 kHz octave band contribution is not included in the determination of the A-weighted level.
Table 4 — Type of noise and determination of sound power levels

Type of noise in the frequency range of theoctave bands centred at
Sound power level to be determined
125 Hz to 8 kHz

16 kHzNo significant noise

A-weighted level (consisting of contribution from 125 Hz to
8 kHz octave bands) in accordance with this Standard

Broad-band noise

A-weighted level (consisting of contribution from 125 Hz to
8 kHz octave bands) in accordance with this Standard andone-third-octave-band sound power levels in 16 kHz octave
band in accordance with the procedure of ECMA-108

Broad-band
or Discrete tone
narrow-band noise aA-weighted level (consisting of contribution from 125 Hz to
8 kHz octave bands) in accordance with this Standard andthe level and frequency of the discrete tone in accordancewith ECMA-108

Multiple tones

A-weighted level (consisting of contribution from 125 Hz to
8 kHz octave bands) in accordance with this Standard andthe levels and frequencies of all tones in the 16 kHz octave
band that are within 10 dB of the highest tone level in theband in accordance with ECMA-108

Discrete tone

Level and frequency of the discrete tone in the 16 kHz octave
band in accordance with ECMA-108

Multiple tones

Levels and frequencies of all tones in the 16 kHz octave bandthat are within 10 dB of the highest tone level in the band inaccordance with ECMA-108

No significant noise b

For noise in 125 Hz to 8 kHz octave bands, sound power level in one-third-octave bands and in octave bands may also
be reported.
a

A significant noise contribution not within the 125 Hz to 8 kHz octave band lies outside the scope of this Standard; inthat case, only ECMA-108 is applicable.
b

7
Method for determination of sound power levels of equipment under essentially
free-field conditions over a reflecting plane
7.1

GeneralThe method specified in this clause provides a direct procedure for determination of the sound power levels of
ITT equipment using essentially free-field conditions over a reflecting plane as specified in ISO 3744 or
ISO 3745. It applies to equipment which radiates broad-band noise, narrow-band noise, noise which contains
discrete frequency components or impulsive noise.
The measurement shall be carried out in an environment qualified in accordance with ISO 3744 or ISO 3745.

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7.2

Measurement uncertainty

Measurements carried out in accordance with this method yield standard deviations of reproducibility for thefrequency range of interest of this Standard which are less than or equal to those given in Table 5.
Table 5 — Typical upper bound values of the standard deviation of reproducibility in determining
sound power levels in a free field over a reflecting plane in accordance with Clause 7
Octave band
centre frequencies
Hz

One-third-octave band
centre frequencies
HzStandard deviation of
reproducibility, σR0dB

125

100 to 160

3,0

250 to 500

200 to 630

2,0

1 000 to 4 000

800 to 5 000

1,5

8 000

6 300 to 10 000

2,5

NOTE 1
For most ITT equipment, A-weighted sound power level is determined by the sound power levels in the 250 Hz
to 4 000 Hz octave bands. The A-weighted sound power level is determined with a standard deviation of approximately
1,5 dB. A larger standard deviation can result when the sound power levels in other bands determine the A-weighted soundpower level.
NOTE 2The standard deviations of reproducibility, σR0 (see 3.3.2), given in Table 5, reflect the cumulative effects of allcauses of measurement uncertainty, including variations from laboratory to laboratory but excluding variations in the soundpower level from equipment to equipment or from test to test which can be caused, for example, by changes in the installation
or operating conditions of the equipment. In quantitative sense, the repeatability, σr (see 3.3.1), of the test results for thesame piece of equipment and the same measurement conditions can be considerably better (i.e. smaller standard
deviations) than the uncertainties given in Table 5 indicate.
NOTE 3
If the method specified in this clause is used to compare the sound power levels of similar equipment that areomnidirectional and radiate broad-band noise, this comparison yields a standard deviation which is less than that given in
Table 5, provided that the measurements are carried out in the same environment.

7.3
7.3.1
7.3.1.1

Test environment
Essentially free field over a reflecting plane
GeneralThe test environment shall provide an essentially free field over a reflecting plane. Criteria for suitable test
environments are defined in ISO 3744 and ISO 3745.
NOTE 1
A plane (floor, wall) is considered to be reflecting (hard) if its absorption coefficient  is less than 0,06 over thefrequency range of interest (e.g. concrete floor:  < 0,01, plastered wall:   0,04, tiled wall:   0,01).
NOTE 2
It is ideal for the test environment (an essentially free field over a reflecting plane, such as a hemi-anechoicroom) to be qualified in accordance with the latest edition of ISO 3744 and/or ISO 3745 as applicable. In practice, however,in case of the existing test environment, it will take some years (so called, transition period) to complete the re-qualification
testing according to applicable updated standards. Such a testing can be needed for test laboratories which meet therequirements of ISO/IEC 17025[12].

7.3.1.2

Qualification in accordance with ISO 3744

For test environments qualified in accordance with ISO 3744, the environmental correction, K2, shall be equal
to or less than 2 dB in each one-third octave band over the frequency range of interest.

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The above requirement for K2 may not be achievable in all frequency bands, even if the test environment issuitable for determining A-weighted sound power levels. Therefore, if the A-weighted sound power level is tobe determined from one-third-octave band levels, the following steps shall be followed to determine whether
this quantity meets the environmental correction criteria of this Standard:a) the A-weighted sound power level is computed in accordance with the procedures in ISO 3744 using
the data from every one-third-octave band within the frequency range of interest and corrected for K2
using the values determined from Annex A in ISO 3744 even when those values exceed K2 = 2,0 dB;b) the computation is repeated, but excluding those bands for which K2 exceeds 2 dB.
If the difference between these two levels is less than 0,5 dB, the A-weighted sound power level determinedfrom the data for all bands can be considered as conforming to the test environmental correction criteria of thisStandard.
7.3.1.3

Qualification in accordance with ISO 3745

For test environments qualified in accordance with ISO 3745, the environmental correction, K2 is assumed to
be 0 dB in each one-third octave band over the frequency range of interest. The above requirement for
qualification in accordance with ISO 3745 may not be achievable in all frequency bands, even if the test
environment is suitable for determining A-weighted sound power levels. Therefore, if the A-weighted soundpower level is to be determined from one-third-octave band levels, the following steps shall be followed todetermine whether this quantity meets the environmental qualification criteria of this Standard:a)the A-weighted sound power level is computed in accordance with the procedures in ISO 3744 using thedata from every one-third-octave band within the frequency range of interest for which the chamber
qualifies in accordance with ISO 3745;b)

the computation is repeated, but excluding those bands for which the chamber does not qualify inaccordance with ISO 3745.

If the difference between these two levels is less than 0,5 dB, the A-weighted sound power level determinedfrom the data for all bands can be considered as conforming to the test environmental qualification criteria of
this Standard.
7.3.2

Meteorological conditions

The requirements of ISO 3744 as applicable shall be followed.
The following conditions are recommended:a)ambient pressure: 86 kPa to 106 kPa;b)temperature: within the range defined by the manufacturer for the equipment, if a range is defined; if norange is so defined by the manufacturer, the recommended range is 15 C to 30 C;c)relative humidity: within the range defined by the manufacturer for the equipment, for processing of paperand card media only, if no range is so defined by the manufacturer, the recommended range is 40 % to70 %.

For equipment whose noise emissions vary with ambient temperature in a prescribed manner (e.g. by varying
the speeds of air-moving devices), the room temperature during the measurement shall be 23 C  2 C.
For equipment whose noise emissions vary with altitude in a prescribed manner (e.g. by varying the speeds of
air-moving devices), either the altitude of the test room shall be less than or equal to 500 m, or the equipment
shall be tested under conditions simulating its operation at an altitude less than or equal to 500 m.
NOTEThis variation of speed of air-moving devices does not refer to the changing speed that is already accounted forin the correction for ambient pressure specified in 7.9.1.

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7.4
7.4.1

Instrumentation
GeneralThe requirements of 7.4, as well as the instrumentation requirements of ISO 3744 or ISO 3745, shall be followed.
Digital integration is the preferred method of averaging.
7.4.2

The microphone and its associated cable

The instrument system, including the microphone and its associated cable, shall meet the requirements of
ISO 3744 or ISO 3745, as applicable. If the microphone is moved, care shall be exercised to avoid introducing
acoustical or electrical noise (e.g. from wind, gears, flexing cables or sliding contacts) that could interfere withthe measurements.
7.4.3

Frequency response of the instrumentation system

The requirements of ISO 3744 or ISO 3745, as applicable, shall be followed.
7.4.4

Reference sound source

The reference sound source shall meet the requirements specified in ISO 6926 over the frequency range ofinterest.
7.4.5

Filter characteristics

The requirements for an instrument specified in accordance with IEC 61260-1, class 1 shall be followed.
7.4.6

Calibration

Before and after each series of measurements, a sound calibrator meeting the requirements of IEC 60942, class
1 shall be applied to each microphone to verify the calibration of the entire measuring system at one or more
frequencies within the frequency range of interest. Without any adjustment, the difference between the readings
made before and after each series of measurements shall be less than or equal to 0,5 dB. If this value is
exceeded, the results of the series of measurements shall be discarded.
NOTE
A “series” of measurements does not require that this verification be conducted “daily”. Other methods forchecking the calibration of the measurement system to insure this requirement will be met can be available. For example,
see JBMIA-TR-28[18].

The calibration of the sound calibrator, the compliance of the instrumentation system with the requirements of
IEC 61672-1, the compliance of the filter set with the requirements of IEC 61260-1 and, if used, the complianceof the reference sound source with the requirements of ISO 6926 shall be verified at intervals in a laboratory
making calibrations traceable to appropriate standards preferably by meeting the requirements of
ISO/IEC 17025 [12].
The sound calibrator should be calibrated at intervals not exceeding 1 year, the reference sound source should
be calibrated at intervals not exceeding 2 years, the compliance of the instrumentation system with therequirements of IEC 61672-1 should be verified at intervals not exceeding 2 years, and the compliance of thefilter set with the requirements of IEC 61260-1 should be verified at intervals not exceeding 2 years.

7.5

Installation and operation of equipment: General requirements

See Clause 5.

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7.6

Measurement surface and microphone positions

7.6.1

GeneralExcept as specified in Annex B, the requirements of ISO 3744 or ISO 3745 shall be followed as applicable. For
most ITT equipment, the preferred measurement surface is hemispherical. If a hemispherical surface is used,then one of the following shall be applied:
a)

B.1;

b)

relevant annex of ISO 3745; orc)relevant annex of ISO 3744 (but, with a minimum of five different microphone heights) .

However, for equipment with tall aspect ratios, such as equipment racks, frames, or cabinets, the cylindricalmeasurement surface specified in B.2 may be preferred. For sources which have a relatively large foot print,
the parallelepiped measurement surface can be more practical than a hemispherical. The conditions of Clause
5 above shall however be followed. The number and location of the microphone positions shall be as specified
in ISO 3744 or ISO 3745, as applicable, except as specified in Annex B of this Standard.
In some cases, e.g. when small equipment emits very low-level noise, it can be helpful to use a hemisphericalmeasurement surface with a smaller radius. For such situations, B.1 defines measurement conditions with ahemisphere radius less than 1 m, but at least 0,5 m.
In order to facilitate the location of the microphone positions, a hypothetical reference surface is defined. Thisreference surface, or “reference box”, is the smallest possible rectangular box (i.e. rectangular parallelepiped)
that just encloses the equipment and terminates on the reflecting plane(s). It has length l1, width l2 and heightl3. Elements protruding from the equipment being tested which are unlikely to contribute to the noise emission
may be disregarded. The microphone positions lie on the measurement surface, a hypothetical surface of area
S, which envelops the equipment as well as the reference box and terminates on the reflecting plane.
The location of the equipment being tested, the measurement surface and the microphone positions are definedby a co-ordinate system with horizontal axes x and y in the ground plane parallel to the length and width of thereference box and with the vertical axis z passing through the geometric centre of the reference box. The x axis
points towards the front of the equipment. The position of the origin for the coordinates of the microphone
positions is:a)for floor-standing equipment: on the floor in the centre of the plane of the reference box which is coplanarwith the room floor;b)

for table-top equipment on a table or on the floor: as for a);c)

for wall-mounted equipment: in the centre of that plane of the reference box which is coplanar with themounting surface;d)for rack-mounted equipment: as for a);e)for hand-held equipment: as for a);f)

for sub-assemblies: as for a).

NOTE
For fixed microphone arrays, either a single microphone can be moved from one position to the next sequentiallyor a number of fixed microphones can be used and their outputs sampled sequentially or simultaneously. Alternatively, acontinuous microphone traverse can be used as specified in ISO 3744.

Near air exhausts, the microphone position shall be selected in such a way that the microphone is not exposedto the air stream, otherwise a windscreen shall be used.

22© Ecma International 2021

The microphones shall be oriented in such a way that the angle of sound incidence is the same as the angle forwhich the microphone has the most uniform frequency response as specified by the manufacturer. For mostpractical cases this will be an orientation towards the origin of the co-ordinate system on the floor.
7.6.2

Microphone positions on the measurement surface

Except as stated in the next paragraph, microphone positions shall meet the requirements of ISO 3744 or
ISO 3745, as applicable, including the requirements for additional microphone positions and for the reductionin the number of microphone positions, where applicable.
If large equipment is to be measured in small rooms providing free-field conditions over a reflecting plane inaccordance with ISO 3745, it can be easier to place the equipment not in the centre of the room but closer to acorner and to arrange the microphone positions in the free field of the room. The equipment should be turned
around so that noise radiation from the different sides of the machine can be determined sequentially.

7.7

Measurement of sound pressure levels

7.7.1

GeneralMeasurements of the sound pressure levels shall be carried out in accordance with ISO 3744 or ISO 3745 andwith the following requirements.
Measurements of the sound pressure level shall be carried out at the microphone positions specified in 7.6 with
A-weighting and/or for each frequency band within the frequency range of interest, if required.Record:−−

the A-weighted sound pressure levels and/or the one-third-octave band sound pressure levels, for the
specified modes of operation of the equipment;
the A-weighted sound pressure levels and/or the one-third-octave band sound pressure levels of the
background noise (including noise from support equipment).

When using a sound level meter, the person reading the meter shall not disturb the sound field at the microphone.
NOTE
Depending on the purposes of the test, it may be the case that one or more repeated measurements are taken
for the source under test. Provided that each of the measurements in the repeated set represent identical conditions for thesource under test, and that they are each valid measurements in accordance with the requirements of this Standard, thearithmetic average of the measured sound pressure levels, in decibels, should be taken as the measurement result from
7.7.

7.7.2

Measurement time interval

The requirements below, in addition to those of ISO 3744, shall be followed, as applicable.
For equipment which performs repetitive operational cycles (e.g. enveloping machines), the measurement timeinterval shall include at least three operational cycles. For equipment which performs a sequence of varying
operational cycles, the measurement time interval shall include the total sequence. Annex C specifies additional
requirements for many types of equipment.
7.7.3

Corrections for background noise

The requirements of ISO 3744 shall be followed, as applicable.
NOTE
When the levels of the background noise in the test room are extremely low and very controlled, it is possiblethat the environment satisfies the absolute and/or relative criteria for background noise in accordance with ISO 3744.

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7.8

Calculation of surface time-averaged sound pressure level

Calculation of surface time-averaged sound pressure level over the measurement surface shall be inaccordance with the relevant procedure of ISO 3744. This includes corrections for background noise, K1, andtest environment, K2. For hemi-anechoic rooms meeting the qualification requirements of ISO 3745, no K2
correction is applied.

7.9
7.9.1

Determination of sound power levels
Calculation of band time-averaged sound power levels

When band data are required, the sound power level, under reference meteorological conditions, of theequipment in each one-third-octave band within the frequency range of interest shall be based on the surface
time-averaged sound pressure level and determined in accordance with the procedure of ISO 3744.
NOTE
The procedures given in ISO 3744 is used to determine the sound power level under reference meteorologicalconditions (ambient pressure 1,013 25 × 105 Pa, temperature 23,0 °C, relative humidity 50 %).

The sound power level in the k-th octave band, LWoct, k, in decibels, if needed, shall be based on one-third-octave
band data, LW1/3, j, and calculated from Formula (1).
7.9.2

Calculation of A-weighted sound power level

For the purposes of this Standard, the A-weighted sound power level, LWA, in decibels, under reference
meteorological conditions, can be derived either directly from A-weighted sound pressure levels, or by
calculation from one-third-octave-band data using the A-weighting values for each band in accordance with theprocedures of ISO 3744.
NOTE
The procedures given in ISO 3744 are used to determine the sound power level under reference meteorologicalconditions (ambient pressure 1,013 25 × 105 Pa, temperature 23,0 °C, relative humidity 50 %).

In the latter case, the A-weighted sound power level, LWA, in decibels, shall be based on the frequency range ofinterest, and calculated from Formula (2).
Some ITT equipment emits high-frequency noise in the 16 kHz octave band. Depending upon the nature ofnoise emissions, Table 4 shows how to handle each situation.
For the determination of A-weighted sound power levels from band levels, this Standard does not extend thefrequency range of interest to include the 16 kHz octave band.
For equipment which emits discrete tone(s) in the 16 kHz octave band, each frequency and level of the tone(s)that is (are) within 10 dB of the highest tone level in the band shall be determined in accordance with theprocedures specified in ECMA-108 (see Table 4). The derived levels are not frequency weighted.
CAUTION — The 16 kHz octave band contribution is not included in the determination of A-weighted level.

8
Method for determination of emission sound pressure levels at defined operator
and bystander positions
8.1

GeneralThe method specified in this clause defines the conditions for determination of the emission sound pressurelevels of ITT equipment at the work station (operator position) and, if there is no operator position, at the
bystander positions in an essentially free field over a reflecting plane in accordance with ISO 11201, accuracy
grade 2 (engineering method). It applies to equipment which radiates broad-band noise, narrow-band noise,
noise which contains discrete frequency components, or impulsive noise.

24© Ecma International 2021

NOTE

The determination specified in this clause is historically based on the engineering method.

Table C.1 identifies whether the types of equipment identified in Annex C shall be measured at the operator
position or bystander positions. If the equipment under test is not specifically included in Annex C (or in
Table C.1), the requester of the test shall specify whether or not the equipment is considered operator-attended.
If so, an operator position shall be defined in accordance with 8.6.2; if not, bystander positions shall be definedin accordance with 8.6.3.
This determination does not apply to sub-assemblies. However, where desired for sub-assemblies, determine
an emission sound pressure level from a previously obtained sound power level using Q = Q1 = 8 dB in
accordance with ISO 11203. This value of Q corresponds to a radial distance of 1 m from a small sub-assemblyradiating hemispherically; for uniformity this value of Q is applicable to all sub-assemblies. Optionally, actual
emission sound pressure levels may be determined at operator or bystander positions, as described in thefollowing.
Determination of whether the noise at the operator position or at the bystander positions contains prominent
discrete tones is specified in Annex D. The method is applicable to both ITT equipment and sub-assemblies.
Determination of whether the noise at the operator position or at the bystander positions contains prominent
tonalities is specified in Annex G based on the hearing model approach in Annex F. The method is applicable
to both ITT equipment and sub-assemblies.

8.2

Measurement uncertainty

Measurements carried out in accordance with this method yield standard deviations of reproducibility for thefrequency range of interest of this Standard which are equal to, or less than, those given in Table 6.
Table 6 — Typical upper bound values of the standard deviation of reproducibility in determining
emission sound pressure level at the operator and bystander positions in an essentially free field overa reflecting plane in accordance with Clause 8
Octave-band centre
frequencies
Hz

One-third-octave-band
centre frequencies
HzStandard deviation of
reproducibility, σR0dB

125

100 to 160

3,0

250 to 500

200 to 630

2,0

1 000 to 4 000

800 to 5 000

1,5

8 000

6 300 to 10 000

2,5

NOTE 1
For most ITT equipment, the A-weighted emission sound pressure level is determined by the emission soundpressure levels in the 250 Hz to 4 000 Hz octave bands. The A-weighted emission sound pressure level is determined witha standard deviation of approximately 1,5 dB. A larger standard deviation can result when the emission sound pressurelevels in other bands determine the A-weighted emission sound pressure level.
NOTE 2
In free-field conditions over a reflecting plane, the standard deviations of reproducibility, σR0 (see 3.3.2), given
in Table 6, reflect the cumulative effects of all causes of measurement uncertainty, including variations from laboratory tolaboratory, but excluding variations in the emission sound pressure level from equipment to equipment or from test to test
which can be caused, for example, by changes in the installation or operating conditions of the equipment. In quantitative
sense, the repeatability, σr (see 3.3.1), of the test results for the same piece of equipment and the same measurement
conditions can be considerably better (i.e. smaller standard deviations) than indicated by the values given in Table 6.
NOTE 3
If the method specified in this clause is used to compare the emission sound pressure levels of similar equipmentthat are omnidirectional and radiate broad-band noise, this comparison yields a standard deviation which is less than thatgiven in Table 6, provided that the measurements are carried out in the same environment.

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8.3
8.3.1

Test environment
GeneralThe measurements shall be carried out in a qualified environment in accordance with ISO 11201, accuracy
grade 2 (engineering method). For convenience, the measurements may be carried out in conjunction with those
performed in accordance with Clause 7.
CAUTION — Installation conditions are not always identical between Clause 7 and Clause 8.
8.3.2

Meteorological conditions

The requirements of ISO 11201, accuracy grade 2 (engineering method) shall be followed.
The following conditions are recommended:a)ambient pressure: 86 kPa to 106 kPa;b)temperature: within the range defined by the manufacturer for the equipment, if a range is defined; if norange is so defined by the manufacturer, the recommended range is 15 C to 30 C;c)relative humidity: within the range defined by the manufacturer for the equipment, if a range is defined;
for processing of paper and card media only, if no range is so defined by the manufacturer, therecommended range is 40 % to 70 %.

For equipment whose noise emissions vary with ambient temperature in a prescribed manner (e.g. by varying
the speeds of air-moving devices), the room temperature during the measurement shall be 23 °C ± 2 °C.
For equipment whose noise emissions vary with altitude in a prescribed manner (e.g. by varying the speeds of
air-moving devices), either the altitude of the test room shall be less than or equal to 500 m, or the equipment
shall be tested under conditions simulating its operation at an altitude less than or equal to 500 m.
NOTEThis variation of speed of air-moving devices does not refer to the changing speed that is already accounted forin the correction for ambient pressure described in the 8.8.1, NOTE.

8.4

Instrumentation

Instrumentation shall meet the requirements of ISO 11201, accuracy grade 2 (engineering method) and the
additional requirements of 7.4.

8.5

Installation and operation of equipment

Equipment shall be installed and operated in accordance with the requirements of Clause 5 except for handheld and table-top equipment.
Hand-held equipment shall be installed so that the equipment is flat on a standard test table, with the front edgeof the device aligned with the front edge of the table. Hand-held equipment may be optionally isolated from thesurface by a small number of elastomeric feet, approximately 12 mm high.
Table-top equipment shall be installed centred on a standard test table, unless otherwise specified in Annex C.
Any table-top equipment combination which includes a keyboard shall be installed such that the smallest
rectangle in the plane of the table and encompassing the keyboard and other units is centred on the top of thestandard test table or as specified in Annex C. Any table-top equipment combination which normally is operated
with a detachable keyboard but which is tested without the keyboard shall be centred on the test table as in thepreceding sentence and as if the keyboard were present, unless otherwise specified in Annex C.
For optional measurement of sub-assemblies intended for use in table-top products, install the sub-assembly inthe centre of a standard test table and isolated from the surface by a small number of elastomeric feet,

26© Ecma International 2021

approximately 12 mm high. For optional measurement of sub-assemblies intended for use in other enclosuresor racks, install the sub-assembly as specified in 5.1.7.

8.6
8.6.1

Microphone positions
General8.6.2 and 8.6.3 specify the ways to define operator and bystander positions, respectively.
For equipment already standardized, Annex C specifies which position(s) is (are) applicable to each category.
See Table C.1.
NOTE
These requirements are in accordance with, but more specific than, those of ISO 11201, accuracy grade 2(engineering method).

8.6.2

At the operator position(s)One or more operator positions shall be specified for equipment which requires operator attention while in theoperating mode.
For equipment operated from a standing position, the microphone shall be located 1,50 m  0,03 m above thefloor [see Figure 1 a), position P1].
For equipment operated from a seated position, the microphone shall be located 1,20 m  0,03 m above thefloor [see Figure 1 b), 2 a) or 2 b), position P2, P3 or P4].
The horizontal distance from the reference box shall be 0,25 m  0,03 m, unless this distance is not
representative of the operator position; in the latter case, the representative operator position shall be describedand used.
For table-top equipment which normally has a detachable keyboard and which is tested without the keyboard(e.g. a desk-top personal computer or a video display unit that is tested without a keyboard), the distance fromthe front end of the reference box, for purposes of determining the operator position, shall be 0,50 m  0,03 m[see Figure 2 b), position P4].
For optional measurement of sub-assemblies intended for use in equipment with a defined operator position,
the above position shall be used for the sub-assembly measurement (i.e. 0,25 m ± 0,03 m if table-top equipment
does not have a detachable keyboard, and 0,50 m ± 0,03 m otherwise from front of reference box, and1,20 m ± 0,03 m above the reflecting plane).
During this measurement the operator should be absent, if possible, or move aside, so that he/she can still
operate the equipment but does not significantly disturb the sound field around the microphone.
For hand-held equipment, the microphone shall be located 1,0 m ± 0,03 m above the floor, and the horizontal
distance from the reference box shall be 0,125 m ± 0,01 m [see Figure 3, position P5].
NOTE
If the sound pressure level at the operator position is measured on operator-attended equipment, thenmeasurement of sound pressure level at a bystander position is not required.

8.6.3

At the bystander positions

For equipment which does not require operator attention while in the operating mode, an operator position may
not be specified. In this case, at least four bystander positions shall be selected and specified to determine themean emission sound pressure level (see 8.8.3). For reporting and/or declaration purposes, this mean value isapplicable, rather than the value at each bystander position.
The bystander positions shall be at a horizontal distance of 1,00 m  0,03 m from the sides of the reference box
and at a vertical distance of 1,50 m  0,03 m above the floor. The four preferred bystander positions are centred© Ecma International 2021

27

horizontally at the front, rear, right and left sides of the reference box. If the length of any side of the referencebox exceeds 2,0 m, additional bystander positions at 1,0 m intervals should be used. For wall-mounted
equipment or for equipment placed against the wall, the three preferred bystander positions are centred at thefront, right, and left sides of the reference box.
For optional measurement of sub-assemblies intended for use in equipment which does not require operator
attention while in the operating mode, install the sub-assembly in accordance with 5.1.7, define the referencebox and apply the provisions of the preceding two paragraphs to define the bystander positions.
8.6.4

Microphone orientation

The microphones shall be oriented in such a way that the angle of sound incidence is the same as the angle forwhich the microphone has the most uniform frequency response. For most practical cases, the primary soundsource is assumed to be either 30° or 45° below horizontal (see Figures 1, 2 and 3).
Dimensions in metresa) Standing operatorb) Seated operator

Figure 1 — Examples of microphone positions for operators of floor-standing equipment
Dimensions in metresa) Seated operator for table-top equipment(case 1: with keyboard)b) Seated operator for table-top equipment(case 2: without keyboard)

Figure 2 — Examples of microphone positions for operators of table-top equipment
Dimensions in metres

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Operator for hand-held equipment
Figure 3 — Example microphone position for operators of hand-held equipment

8.7

Measurement of sound pressure levels

8.7.1

GeneralMeasurements of the sound pressure level required by this clause shall be carried out at the microphone
positions specified in 8.6 with A-weighting and/or for each frequency band within the frequency range of interest.
Record:a) the A-weighted sound pressure levels and/or the one-third-octave band sound pressure levels, for the
specified modes of operation of the equipment;b) the A-weighted sound pressure levels and/or the one-third-octave band sound pressure levels of the
background noise (including noise from support equipment).
When using a sound level meter, the person reading the meter shall not disturb the sound field at the microphone.
If spatial fluctuations occur, due to interferences or standing waves, it is recommended that the microphone be
moved by approximately 0,1 m in a vertical plane around the nominal measurement position, and the averagesound pressure level recorded.
In order to obtain the emission sound pressure level at a specified position, only background noise corrections
K1 (K1A for A-weighted sound pressure level) shall be applied to the measured sound pressure level, in
accordance with the procedure of ISO 11201, accuracy grade 2 (engineering method) (see 8.7.3.);
environmental corrections, K2 (K2A for A-weighted sound pressure level) shall not be applied.
NOTE 1
Determination of whether the noise emission at the operator position or at the bystander positions contains
prominent discrete tones is specified in Annex D. Determination of whether the noise at the operator position or at the
bystander positions contains prominent tonalities is specified in Annex G based on the hearing model approach in Annex F.

Measurements of the C-weighted peak emission sound pressure level, LpCpeak, shall be carried out at the
microphone positions specified in 8.6 if any of the C-weighted peak sound pressure levels at the specified
positions exceeds 120 dB.
NOTE 2
Some regulations require declaration of C-weighted peak emission sound pressure levels greater than 130 dB.
Contemporary ITT equipment is unlikely to emit C-weighted peak emission sound pressure levels (LpCpeak) greater than
120 dB, which is set in this Standard as a conservative threshold above which measurement and reporting are required.
NOTE 3
Depending on the purposes of the test, it may be the case that one or more repeated measurements are taken
for the source under test. Provided that each of the measurements in the repeated set represent identical conditions for thesource under test, and that they are each valid measurements in accordance with the requirements of this Standard, thearithmetic average of the measured sound pressure levels, in decibels, should be taken as the measurement result of thisclause.

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8.7.2

Measurement time interval

The measurement time interval shall be as specified in 7.7.2.
8.7.3

Corrections for background noise

The requirements of ISO 11201, accuracy grade 2 (engineering method) shall be followed.
NOTE
When the background noise levels in the test room are extremely low and very controlled, it is possible that theenvironment satisfies the absolute and/or relative criteria for background noise in accordance with ISO 11201, accuracy
grade 2 (engineering method).

8.8

Determination of emission sound pressure levels

8.8.1

Calculation of band emission sound pressure levels

The emission sound pressure level, under reference meteorological conditions, of the equipment in each onethird-octave band within the frequency range of interest (see 3.2.11) is obtained by using the procedure of
ISO 11201, accuracy grade 2 (engineering method).
NOTE The procedures given in ISO 11201 are used to determine the emission sound pressure level underreference meteorological conditions (ambient pressure 1,013 25 × 105 Pa, temperature 23,0 °C, relative
humidity 50 %).
The emission sound pressure level in the k-th octave band, Lpoct, k in decibels, if needed, shall be based on onethird-octave band data, and calculated as per Formula (3):3k

L poct,k = 10 lg

 10

j =3k − 2

0,1L p1/ 3, j

dB

(3)

where
k

is an identification number of an octave band within the frequency range of interest (see Table 2);

Lp1/3, jis the emission sound pressure level, in decibels in the j-th one-third-octave band (see Table 3);j
is an identification number lying within the range of (3k – 2) and 3k, and which identifies the three one-thirdoctave bands which make up the k-th octave band.
8.8.2

Calculation of A-weighted emission sound pressure levels from band levels

For the purpose of this Standard, A-weighted emission sound pressure levels, LpA, in decibels, can be derived
either directly from A-weighted sound pressure level, or by calculation from one-third-octave band data using
the A-weighting values for each band in accordance with the procedures of ISO 11201, accuracy grade 2(engineering method).
NOTE
The procedures in ISO 11201 are used to determine the emission sound pressure level under reference
meteorological conditions (ambient pressure 1,013 25 × 105 Pa, temperature 23,0 °C, relative humidity 50 %).

In the latter case, the A-weighted emission sound pressure level, LpA, in decibels, shall be based on theapplicable frequency range of interest, and calculated as per Formula (4):21

L pA = 10lg

10
j =1

(

0,1 LW 1/ 3, j + A j

)
dB

(4)

where

30

© Ecma International 2021

Lp1/3j is the emission sound pressure level, in decibels, in the j-th one-third-octave band;
Aj

is the A-weighting value corresponding to the j-th one-third-octave band from Table 3;jis an identification number of one-third-octave band within the frequency range of interest.

Some ITT equipment emits high-frequency noise in the 16 kHz octave band. Depending upon the nature ofnoise emissions, Table 4 shows how to handle each situation. For the purposes of Clause 8, “sound power level”
or “level” in Table 4 shall be replaced by “emission sound pressure level”. The derived levels are not frequency
weighted.
For the determination of A-weighted emission sound pressure levels from band levels, this Standard does notextend the frequency range of interest.
For equipment which emits discrete tone(s) in the 16 kHz octave band, each frequency and level of the tone(s)that is (are) within 10 dB of the highest tone level in the band shall be determined in accordance with theprocedures specified in ECMA-108 (see Table 4).
CAUTION — The 16 kHz octave-band contribution is not included in the determination of the A-weighted level.
8.8.3

Calculation of the mean emission sound pressure level at the bystander positions

If bystander positions are defined, the mean A-weighted emission sound pressure level, LpA, and the mean band
emission sound pressure levels, Lp, in decibels (reference: 20 µPa), if required, at bystander positions definedin 8.6.3, shall be calculated as specified in Formula (5):
1 N
0,1L pi L p = 10lg 
10 N i =1

dB



(5)

where
Lpi is the band emission sound pressure level, in decibels (reference: 20 µPa), resulting from measurement at
the i-th bystander position;N

is the number of bystander positions.

For the A-weighted emission sound pressure level, the symbols Lp and Lpi are replaced by LpA and LpAi,
respectively.

9

Measurement uncertainty

The uncertainties of sound power levels, u(LW), in decibels, and emission sound pressure levels, u(Lp), in decibels,
determined in accordance with this Standard are estimated by the total standard deviation, σtot, in decibels, as given in
Formulae (6) and (7):u ( LW )   tot( )u L p   tot

(6)

(7)

This total standard deviation is obtained by using the modelling approach described in ISO/IEC Guide 98-3[13]. This requires
a mathematical model, which in case of lack of knowledge, can be replaced by results from measurements, including resultsfrom round robin testing.
The guidance on the development of information on measurement uncertainty contained in the relevant clauses of ISO 3741,
ISO 3744 and ISO 11201 (only engineering method), as applicable, can be used for this Standard.

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In this context, the total standard deviation, σtot, is expressed by the standard deviation of reproducibility of the method, σR0,
in decibels, and the standard deviation, σomc, in decibels, describing the uncertainty due to the instability of the operating
and mounting conditions of the equipment under test in accordance with Formula (8):2
 tot =  R2 0 +  omc.

(8)

For determination of the total standard deviation, see Table 7.

Table 7 — Parameters to determine the total standard deviation,  tota

Measurement
methodQuantity to be
determinedStandard deviation of Uncertainty due to the instability of theoperating and mounting conditions ofreproducibility, σR0
the equipment under test, σomc

Clause 6

Sound power level

See Table 1a

See relevant clause and annex of
ISO 3741

Clause 7

Sound power level

See Table 5a

See relevant clause and annex of
ISO 3744 or ISO 3745, as applicable

Clause 8

Emission soundpressure level

See Table 6a

See relevant clause and annex of
ISO 11201 (engineering method only)

For details of the values of Tables 1, 5 and 6, see Reference [19].

If the uncertainty of measurement is to be reported, the expanded measurement uncertainty, U, in decibels, canbe calculated from σtot as per Formula (9):U = k tot(9)

The value of U depends on the degree of confidence that is desired. In general, it is 95 %, and the practicalexamples are as follows:— For a normal distribution of measured values, there is 95 % confidence that the true value lies within therange (LW − U) to (LW + U) [or (Lp − U) to (Lp + U)]. This corresponds to a coverage factor of k = 2.
— If the purpose of determining the sound power level or emission sound pressure level is to compare theresult with a limit value, it can be more appropriate to apply the coverage factor for a one-sided normal
distribution. In that case, the coverage factor k = 1,6 corresponds to a 95 % confidence level.
NOTE
For each quantity to be determined (see Table 9), the details of determination of the value of U (including
statistical concepts, such as confidence level, coverage factor, normal distribution, etc.) are explained in each of the relevant
clause and annex of the basic noise emission standards (i.e. ISO 3741, ISO 3744, ISO 3745 or ISO 11201), as applicable.

10

Information to be recorded and reported

10.1

Information to be recorded

10.1.1

GeneralThe information specified in 10.1.2 to 10.1.5 shall be recorded, when applicable. In addition, any deviation fromany requirement in this noise test code or from the basic noise emission standards (i.e. ISO 3741 for Clause 6,
ISO 3744 or ISO 3745 as applicable for Clause 7, or ISO 11201 for Clause 8) upon which it is based shall berecorded together with the technical justification for such deviation.
All requirements for recording and reporting specified in the basic noise emission standards are also
requirements of this Standard. That is, the requirements below are necessary but not sufficient.

32© Ecma International 2021

10.1.2

Equipment under test

The following information shall be recorded:a) a description of the equipment under test (including main dimensions; name, model and serial numberof each unit; name, model and serial number of noise-producing components and sub-assemblies inthe equipment under test);b) a complete description of the idle and operating modes, including operating speed, data medium used
and the test programme in terms that are meaningful for the type of equipment being tested;c) a complete description of the installation and mounting conditions;d) the location of the equipment in the test environment;e) the location and functions of an operator, if present;f) the nominal power line frequency, in hertz (e.g. 50 Hz), and the measured power line voltage, in volts;g) a sample of typical hardcopy output of the product being tested, which, when applicable, should be
filed as part of the recorded data;h) a statement as to whether the noise emission depends on room temperature, if known.
The following information is given for recording the time signal.
For each operating mode, for the operator position (if defined), otherwise for the bystander position (if defined)with the highest A-weighted sound pressure level, the time signal of sound pressure may be recorded, of atleast the measurement time interval specified in 8.7.2, with relevant information of the name of the product, thetest mode, the microphone position, and the A-weighted sound pressure level of the signal. Dolby1 or otherdigital noise reduction features shall not be used. This Standard does not require that a separate calibration
signal be recorded. The bias information used in recording shall be filed with the time signal data.
10.1.3

Acoustical environment

The following information shall be recorded.
a) If the sound power level is determined in accordance with Clause 6 (ISO 3741):
1) a description of the test room, including dimensions, shape, surface treatment of the walls, ceilingand floor; a sketch showing location of source and room contents;
2) a description of diffusers, or rotating vanes, if any;3) qualification of reverberation test room in accordance with ISO 3741;
4) the air temperature, in degrees Celsius, relative humidity, as a percentage, and ambient pressure
in kilopascals.
b) If the sound power level is determined in accordance with Clause 7 (ISO 3744 or ISO 3745):
1) a description of the acoustical environment, if indoors, the size and acoustic characteristics of theroom, including absorptive properties of the walls, ceiling and floor; a sketch showing the locationof the equipment under test;2) environmental corrections, K2, resulting from the acoustical qualification of test environment inaccordance with the relevant procedure of ISO 3744, unless the environment has been qualified
in accordance with ISO 3745 - in the case of compliance with ISO 3745, this fact should bestated;3) the air temperature, in degrees Celsius, relative humidity, as a percentage, and ambientpressure, in kilopascals.
c) For emission sound pressure level at the operator and bystander positions in accordance with
Clause 8 [ISO 11201, accuracy grade 2 (engineering method)]:1)

Dolby is an example of a suitable product available commercially. This information is given for theconvenience of users of this Standard and does not constitute an endorsement by Ecma of this product.

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NOTE 1
The type of information below is the same as for sound power level determination, just described, but the values
can differ from those recorded for sound power level. If the information recorded for sound power level determination inaccordance with the preceding paragraph is applicable here, it is sufficient to so note in the test file.

1) a description of the acoustical environment, if indoors, the size and acoustic characteristics of theroom, including absorptive properties of the walls, ceiling and floor; a sketch showing the location of
the equipment under test;2) environmental corrections, K2, resulting from the acoustical qualification of test environment inaccordance with the relevant procedure of ISO 3744, unless the environment has been qualified inaccordance with ISO 3745; in the case of conformance with ISO 3745, this fact should be stated;
NOTE 2
Environmental corrections K2 are not intended to be used to modify the measured values but is included as partof the test record as an indication of the quality of the measurement.

3) the air temperature in degrees Celsius, relative humidity as a percentage, and ambient pressure inkilopascals.
10.1.4

Instrumentation

The following information shall be recorded:a) equipment used for the measurements, including name, type, serial number and manufacturer;b) bandwidth of frequency analyser [including a digital Fast Fourier Transform (FFT) analyser, if used in
Annex D];c) frequency response of the instrumentation system;d) method used for daily checking of the calibration of the microphones and other system components;e) the date and place of any required periodic calibrations;f) the test method used for determination of:1) the mean time-averaged sound pressure level in accordance with ISO 3741; or the surface
time-averaged sound pressure level in accordance with ISO 3744;
2) the mean value of the emission sound pressure level at the operator or bystander positions, asapplicable, in accordance with ISO 11201;
10.1.5

Acoustical data

The following information shall be recorded.
a) If the sound power level is determined in accordance with Clause 6 (ISO 3741):
1) location and orientation of the microphone traverse (path) or array (a sketch should be included if
necessary);2) the corrections, if any, in decibels, applied in each frequency band for the frequency response of
the microphone, frequency response of the filter in the passband, background noise, etc.;
3) the values of the difference between the sound power and sound pressure levels produced by thereference sound source (LWr – Lpr), in decibels, as a function of frequency;
4) the band pressure level readings, in decibels, to at least the nearest 0,1 dB for the calculations inaccordance with ISO 3741;
5) the sound power levels in decibels (reference: 1 pW) in octave and/or one-third-octave bands,
tabulated or plotted, rounded to the nearest 0,1 dB;
6) the sound power level in decibels (reference: 1 pW), under reference meteorological conditions, inoctave and/or one-third-octave bands, tabulated or plotted to the nearest 0,1 dB;
7) the A-weighted sound power level in decibels (reference: 1 pW) rounded to the nearest 0,1 dB;
8) the A-weighted sound power level in decibels (reference: 1 pW), under reference meteorologicalconditions, rounded to the nearest 0,1 dB;

34© Ecma International 2021

9) the date, time and place that the measurements were carried out, and the name of the person
who carried out the measurements.
b) If the sound power level is determined in accordance with Clause 7 (ISO 3744):
1) the shape of the measurement surface, the measurement distance, the location and orientation of
microphone positions (including both key microphone positions and additional ones, if required) orpaths used plus, if traversing microphones were used, the maximum traversing speed along apath and microphone orientation;2) the area, S, in square metres, of the measurement surface;3) the corrections, if any, in decibels, applied in each frequency band for the frequency response of
the microphone, and the frequency response of the filter in the passband;4) the background noise correction, K1 (A-weighted or in frequency bands), for the surface
time-averaged sound pressure levels;
5) the background noise level measured at each point and the average background sound pressurelevels;6) the environmental corrections, K2 (A-weighted and in frequency bands), and the method by which
they were determined in accordance with one of the procedures of ISO 3744;
7) the A-weighted surface time-averaged sound pressure level and the band surface time-averaged
sound pressure level, L p , for each frequency band of interest, rounded to the nearest 0,1 dB;
8) the sound pressure levels, Lpi (A-weighted or in frequency bands), at each measuring point, i;9) the A-weighted sound power level, LWA, and the band sound power level, LW, for each frequency
band of interest, rounded to the nearest 0,1 dB;
10) the A-weighted sound power level, LWA, and the band sound power level, LW, under reference
meteorological conditions, for each frequency band of interest, rounded to the nearest 0,1 dB;
11) the date, time and place that the measurements were carried out, and the name of the person
who carried out the measurements.
c) For emission sound pressure levels at the operator or bystander positions, as applicable, in
accordance with Clause 8 [ISO 11201, accuracy grade 2 (engineering method)]:1) the measurement positions and microphone orientations (preferably including a sketch);
2) if one or more operator positions are defined in accordance with 8.6.2, the A-weighted emission
sound pressure level LpA, the band emission sound pressure levels, if required, and the
C-weighted peak emission sound pressure level, LpC,peak, if greater than 120 dB, measured at theoperator position(s), for both the idle and operating modes, in decibels, rounded to the nearest
0,1 dB;3) if bystander positions are defined in accordance with 8.6.3, the A-weighted emission soundpressure levels at the bystander positions, the mean A-weighted emission sound pressure level
LpA, and the mean band emission sound pressure levels, if required, calculated in accordance with
8.8.3 and the C-weighted peak emission sound pressure level LpCpeak, if greater than 120 dB (seeNOTE 2 to 8.7.1) at the bystander position with the highest A-weighted emission sound pressurelevel, for both the idle and operating modes, in decibels, rounded to the nearest 0,1 dB;4) all emission sound pressure levels, in decibels, under reference meteorological conditions;5) optionally, the frequency, in hertz, of any prominent discrete tones identified in accordance withthe procedures of Annex D and the value of the tone-to-noise ratio ∆LT and/or prominence ratio∆LP as applicable, in decibels, associated with that prominent discrete tone, or the frequency, in
Hertz, of prominent tonalities identified in accordance with the procedures of Annex G and thecorresponding psychoacoustic tonality value;
6) A-weighted background noise levels and background noise correction, K1A, at each specified
position, and as required, background noise levels and correction, K1, in frequency bands;
7) the date, time and place where the measurements were carried out, and the name of the person
who carried out the measurements.

© Ecma International 2021

35

10.2

Test report

The test report shall contain at least the following information:a) A statement of whether the sound power levels and the emission sound pressure levels at operator or
bystander positions, as applicable, have been obtained in full conformity with the procedures specified
in this Standard, i.e. ECMA-74:2019, and ISO 3741, ISO 3744 or ISO 3745, as applicable, andISO 11201. Any deviation from any requirement of these International Standards shall be reported,
together with the technical justification for such deviation;b) A statement that these sound power levels are expressed in decibels (reference: 1 pW) rounded to
the nearest 0,1 dB and that these emission sound pressure levels are expressed in decibels(reference: 20 µPa), rounded to the nearest 0,1 dB;c) A statement that “Measured values in this report are for use in planning or in determining declaredvalues. They are not to be confused with the declared values”.
d) The name(s) and model number(s) of the equipment under test;e) The A-weighted sound power level, LWA, under reference meteorological conditions, in decibels, for
the idle mode and the operating mode(s) (reference: 1 pW).
f) The sound power levels, LW, under reference meteorological conditions, in decibels, in octave or onethird-octave bands, if required, for the idle mode and the operating mode(s); the bandwidth used shallbe stated (reference: 1 pW);g) If one or more operator positions are defined in accordance with 8.6.2, the highest A-weighted
emission sound pressure level, LpA, and if required, the band emission sound pressure levels, underreference meteorological conditions, in decibels (reference: 20 µPa), at the operator position(s) for theidle and operating modes;h) If bystander positions are defined in accordance with 8.6.3, the mean A-weighted emission soundpressure level, LpA, and, if required, the mean band emission sound pressure levels in decibels(reference: 20 µPa), under reference meteorological conditions, at the positions specified in 8.6.3
around the equipment for the idle and operating modes;i) A detailed description of operating and installation conditions of the equipment being tested withreference to the specific subclause of Annex C (including publication date and edition), if applicable(e.g. “operating and installation conditions in accordance with C.20 of ECMA-74:2019, 16th edition”). If
additional, or substitute, operating conditions or operating modes have been defined in accordancewith 5.3, these shall be clearly described in the report.
j) For each of the reported sound power levels or emission sound pressure levels, respectively, if theuncertainty of measurement is required, the corresponding expanded measurement uncertainty canbe reported according to Formula (9).
NOTE 1
To avoid confusion between emission sound pressure level in decibels (reference: 20 µPa) and sound power
levels in decibels (reference: 1 pW), sound power level can be expressed in bels, using the identity 1 bel = 10 decibels.
NOTE 2For the determination of declared noise emission values for ITT equipment in accordance with ECMA-109 apositive number is added to the average measured value in decibels of sound power level based on statistical considerations
to account for both random measurement errors and production variations; the sum is divided by 10 and expressed in bels.

Information in a) to j) may be supplemented by one of the following statements, which describe the character ofthe noise as determined in accordance with Annex D:1) no prominent discrete tones;
2) prominent discrete tones;
Items 1) and 2) shall be supplemented with a statement of the method used to identify prominent discrete tones.
Additional statements on the character of the noise in accordance with Annex G may also be given:a) no prominent tonalities;b) prominent tonalities

36© Ecma International 2021

NOTE 3130 dB.

Some regulations require the reporting of the C-weighted peak emission sound pressure level if greater than

© Ecma International 2021

37

38

© Ecma International 2021

Annex A(normative)
Test accessories

A.1 Standard test table
The design for the standard test table is shown in Figure A.1. The top of the table shall be bonded laminatedwood, 0,04 m to 0,10 m thick, having a minimum area of 0,5 m2 and lateral dimensions 0,75 m - 0,05 m/+ 0.03 m.
The height of the table shall be 0,75 m  0,03 m. The table may have a slot in its top plate to allow paper to beinserted for printers which feed the paper from underneath their bottom cover. A slot 0,015 m by 0,400 m inlateral dimensions has been found practical for most printer paper.
0,75 m0,04 to 0,10 m

Legs & braces:
screwed &bonded0,75 mIsolatingpads

97-0036-A

Figure A.1 — Standard test table
Dimensions in metres© Ecma International 2021

39

A.2 Typing robot
The typing robot shall be designed to operate a keyboard in the manner specified in this Standard. The robot
here described uses eight solenoids, each being individually adjustable to operate one of the selected keyboard
keys.
The requirements for this robot are:a) the noise of the robot shall meet the requirements for background noise of this Standard;b) the stroke of each solenoid plunger shall fully release the key in its upper position and push itcompletely down to its stop; a total stroke of 6 mm to 7 mm should be sufficient for most types ofkeyboards including typewriters;c) the electrical input signal shall be a rectangular pulse of 50 ms duration, and of adjustable amplitude;d) the solenoid characteristics shall provide an increasing force during key-down motion, as shown in
Figure A.2 — a suitable design is shown in Figure A.3;e) the plunger mass shall be 20 g ± 1 g; its end shall be soft (e.g. closed-cell foam, 40 Shore A).
A complete operation of a single key includes the following three steps, which are shown in Figure A.4:a) Home position
The plunger rests under its own weight with its soft end on the key.
b) Key operation
When excited by the solenoid, the plunger pushes the key down until it has reached its stop position. The
adjustment of the solenoid should give a plunger clearance of 1 mm; an appropriate mark at the upper plunger
end will facilitate this adjustment;c) Key return
The plunger is returned only by the key spring. The plunger return stop shall be soft and allow a maximum
overshoot of 0,5 mm; the plunger returns to its home position, resting on the key.
NOTE

40

The specification is based on the design of the robot described in Reference [21].

© Ecma International 2021

Magnetic force (N)

12
10
8
6
4
2

97-0037-A

0

1

2

3

4

5

6

7

8 Stroke (mm)Figure A.2 — Solenoid characteristics for a plunger stroke of 4 mm

97-0038-A

Figure A.3 — Solenoid cross section© Ecma International 202141

4-6 mm

0,5 mm max
overshoot97-0039-A

Step 1.
Home position

Step 2.
Key operation

Step 3.
Key return

Figure A.4 — Individual steps of the solenoid operation

42© Ecma International 2021

Annex B(normative)
Measurement surfaces

B.1 Hemispherical measurement surface
Refer to ISO 3744 for the requirements for microphone locations and geometry of the hemisphericalmeasurement surface and microphone array, supplemented by the following additional conditions:a) When using fixed microphone positions, the microphone positions given in ISO 3744 for sources
emitting discrete tones shall be used for all sources. The co-ordinates for this array are reproduced inTable B.1;b) When using the coaxial circular paths arrangement specified in ISO 3744, it is recommended that aminimum of 10 heights be used.
Other acceptable alternatives are described in the relevant annexes of ISO 3745.
Table B.1 — Co-ordinates of microphone positions for equipment emitting discrete tones
Position

x/r

y/r

z/r

1

0,16

- 0,96

0,22

2

0,78

- 0,60

0,20

3

0,78

0,55

0,31

4

0,16

0,90

0,41

5

- 0,83

0,32

0,45

6

- 0,83- 0,400,38

7- 0,26- 0,65

0,71

8

0,74

- 0,070,67

9- 0,26

0,50

0,83

10

0,10

- 0,100,99

For the purpose of this Standard, for small equipment which emits very low level noise, a hemisphericalmeasurement surface with a radius less than 1 m, but at least 0,5 m, may be used, provided that the reduced
radius is greater than or equal to twice the characteristic source dimension (specified in ISO 3744). If the radius
is reduced below 1 m, the lower end of the frequency range of interest becomes higher. To minimize the nearfield effects, the 0,5 m radius would have a corresponding lower frequency limit of approximately 172 Hz (basedon a requirement of one-quarter of the wavelength of sound at the lowest frequency of interest). Additional
information is given in References [22], [23] and [24].

© Ecma International 2021

43

B.2 Cylindrical measurement surface
B.2.1

GeneralFigure B.1 illustrates the cylindrical measurement surface, having microphones located along the side and topof the cylinder. The cylinder shall be centred around the reference box with the centre of the cylinder’s basecorresponding to the centre of the reference box base. The dimensions of the reference box, l1, l2, and l3, andthe reference distances to the cylinder, d1, d2, and d3 are as shown. For the purposes of this annex, thedimensional labels shall be assigned so that l1  l2.

B.2.2

Selection of size of cylindrical measurement surface

The microphone positions lie on the measurement surface, a hypothetical cylindrical surface enveloping thesource and having a total area S equal to the sum of the area of the top circular surface, Stop, and the area ofthe side vertical surface, Sside are given by Formulae (B.1) to (B.3):
S = Stop + Sside(B.1)

Stop = R2(B.2)

Sside = 2RH

(B.3)

where

R

is the radius of the cylinder, given by Formula (B.4)

R = l1/2 + d1 = l 2 /2 + d2
H

(B.4)

is the height of the cylinder, given by Formula (B.5)
H = l3 + d3.

(B.5)

Due to the fact that the microphones are associated with unequal sub-areas, both d 3 and d 1 may be selected
arbitrarily based on the size of the equipment under test or other considerations. It is recommended that bothof these be set to the same value, preferably 1 m, but neither shall be less than 0,5 m. Furthermore, none ofthe distances d1, d2, or d3 shall be greater than 1,5 times either of the others (e.g. this condition is met for d1 andd2 provided d1 ≥ l1 – l2). With d 3 and d 1 selected, H and R are defined and d2 defaults to
d2 = R – l2/2.

(B.6)

In certain cases, such as for large machines where l1 and l2 are of the same magnitude, the side microphones
can pass too close to the machine during their traverse even when the above constraints are met. In view ofthis, the radius, R, shall be large enough such that the side microphones remain more than 0,25 m from any
corner of the reference box.

44

© Ecma International 2021

B.2.3

Selection of microphone positions on the cylindrical measurement surface

The microphones on the cylindrical measurement surface are associated with unequal sub-areas, as describedin the following. The microphones are located along the top circular and side vertical measurement surfaces of
the cylinder and may either sweep out continuous paths (circular traverses) along these measurement surfaces
or be located at fixed positions on equally spaced “slices” of the cylindrical vertical surface. It is recommended
that continuous paths be used for the microphones for sources emitting steady noise. Fixed microphone
positions shall be used when the source emits non-steady noise. However, for either steady or non-steady noise,
if fixed microphone positions are used to sample over the circular traverses, at least 12 equally spaced angular
positions (i.e., at 30° spacing or less) shall be used, starting from an initial angular position perpendicular to oneof the sides of the reference box. The traverses may be implemented by either rotating the microphones,
keeping the source stationary, or rotating the source, keeping the microphones stationary. When fixedmicrophone positions are used, the number of angular positions may be reduced if preliminary investigations
for a particular family of noise sources show that the surface sound pressure levels determined using the
reduced number of positions deviate by no more than 0,5 dB from those using the complete set of positions.
This can be practical, for example, when the pattern of sound emission from the source is symmetrical.
The following requirements govern the number of side microphones, Nside, the number of top microphones, Ntop,

and the associated sub-areas:a) Nside  H / H0

(B.7)

where H0 is set to 0,5 m to achieve adequate vertical sampling by limiting the spacing to 0,5 m or less.
b) Nside  4(B.8)c) Ntop  R/R0

(B.9)

where R0 is set to 0,5 m to achieve adequate radial sampling by limiting spacing to 0,5 m or less.
d) Ntop  2.

(B.10)The vertical side microphones are associated with equal sub-areas, Si, where Si = Sside / Nside, and positioned
such that the i-th microphone is at a height, from the floor, hi, given by Formula (B.11):hi =(i − 1/ 2) H
N side .

(B.11)The mean time-averaged sound pressure level over the side vertical measurement surface, L p, side is given
by Formula (B.12):
 1 N side
0,1L p, side, i dB
L p, side = 10 lg 10
 N side i =1






(B.12)

where L p,side,i is the frequency-band time-averaged sound pressure level, in decibels, measured along the i-th
microphone traverse or at the i-th microphone position on the side surface.
The top microphones are associated with unequal sub-areas, Sj, and are spaced equally along the radius of the
top circular measurement surface. The outer radius of the j-th sub-area is given by Formula (B.13):
R j = jR / N top(B.13)and the position of each top microphone is given by Formulae (B.14) and (B.15):© Ecma International 2021

45

(

)

r j = R j −1 + R j − R j −1 2 for j > 1(B.14)

r1 = R1 2.

(B.15)

andThe mean time-averaged sound pressure level over the top circular surface is given by Formula (B.16):
N top


1
0,1L p, top, j L p, top = 10 lg 
S j 10dB
 S top

j
=
1





(B.16)

where
L p,top, jis the frequency-band time-averaged sound pressure level, in decibels, measured along the j-th
microphone traverse or at the j-th microphone position on the top circular measurement surface.

Stop is the total area of the top circular measurement surface.

(

S j =  R 2j − R 2j −1) for j > 1(B.17)

S 1 =  R12(B.18)

Figure B.2 illustrates an example of the cylindrical microphone array for five vertical side microphones and four
top microphones.

B.2.4
Calculation of the mean time-averaged sound pressure level over the cylindricalmeasurement surface
The mean time-averaged sound pressure level from the array of microphones over the cylindrical measurement
surface, for the chosen mode of operation of the equipment under test, is given by Formula (B.19):
L p = 10lg

1
0,1L p,top
0,1L p,side 
S top 10
+ S side 10
 dB
S 


(B.19)

where S, L p,top and L p,side are given by Formulae (B.1), (B.16) and (B.12), respectively.
NOTE 1

The quantity L p above is equivalent to the quantity Lp(ST) in ISO 3744; i.e. the quantity that is subsequently

corrected for background noise and the test environment before computing the surface time-averaged sound pressure level.
NOTE 246

Additional details about the cylindrical measurement surface can be found in References [25], [26] and [27].

© Ecma International 2021

KEY
1 to 6 side microphone paths
7 to 9 top microphone paths
10 reference box
11 reflecting planed1, d2, d3 reference distances to the cylinder
H cylinder height
l1, l2, l3 reference box dimensions
R cylinder radiusFigure B.1 — Example 1: Illustration of the cylindrical measurement surface and circular microphone
traverses showing the arrangement using six side microphones and three top microphones.

© Ecma International 2021

47

KEY
1 axis of rotation of microphone traversing mechanism
2 dimensions of corresponding areas of cylinder
3 locations of microphone traverses
H cylinder height
R cylinder radiusFigure B.2 — Example 2: Illustration of the cylindrical measurement surface and microphone arrayshowing an arrangement using five side microphones and four top microphones.

48© Ecma International 2021

Annex C(normative)
Installation and operating conditions
for specific equipment categories

C.1 General
This annex specifies installation and operating conditions for many specific categories of Information
Technology and Telecommunication (ITT) equipment. During testing of such equipment, the specified conditions
shall be satisfied in order to be in compliance with this Standard. In general, the conditions specified in thisannex are considered to be typical of average end use. Because the noise emission levels of the equipment
covered by this annex may vary significantly depending on how the equipment is installed and operated during
the tests, the primary purpose of specifying the installation and operating conditions is to ensure that the
acoustical measurements are taken uniformly across different laboratories testing the same type of equipment.
Reported noise emission levels for ITT equipment measured in compliance with this Standard may then becompared or otherwise assessed without having to know the specific details of the installation and operating
conditions used during the tests.
For categories of equipment not covered in this annex, the actual installation and operating conditions usedduring the test shall be described and justified (e.g., as to their representation of typical operating conditions)and test conditions used shall be described and justified (e.g., as to their representation of typical operating
conditions) in the test report.
The operating conditions are strictly the same for the determination of both sound power levels and emission
sound pressure levels at specified positions (see Clause 3 for definitions of these quantities).
The following categories of equipment are included:© Ecma International 2021

49

C.2
C.3
C.4
C.5
C.6
C.7
C.8
C.9
C.10
C.11
C.12
C.13
C.14
C.15
C.16
C.17
C.18
C.19
C.20
C.21
C.22
C.23
C.24

Typewriters
Character- and line-printers
Teleprinters
Keyboards
Copiers (duplicators)
Card readers and card punches
Magnetic tape units
Disk units and storage sub-systems
Visual display units and terminals
Electronic units
Microform readers
Facsimile machines (Telecopiers) and page scanners
Cheque processors
Personal computers and workstations
Single-function printers (SFP)
Self-service automatic teller machines
Rack-mountable units and rack-enclosed systems
CD- and DVD-ROM drives
Data projectors
Multi-function printers (MFP)
Hand-held computing and media playback devices
Digital media recorders and playback units for consumer use
Large format printers

For equipment capable of performing the functions of more than one category, for example printing and facsimiletransmission, see 5.3.
When emission sound pressure level information is needed for the above categories of equipment, Table C.1
shall be used to determine whether an operator position or bystander positions measurements are required.

50© Ecma International 2021

Table C.1 — Equipment measurement position(s) for the determination of emission sound pressurelevel aEquipment categories

Operatorposition

Bystander
positions

C.2

Typewriters

X

C.3

Character- and line-printers

X

C.4

Teleprinters

X

C.5

Keyboards

C.6

Copiers (duplicators)

X

C.7

Card readers and card punches

X

C.8

Magnetic tape unitsX

C.9

Disk units

X

X

Storage sub-systems
C.10

Visual display units and terminals

C.11

Electronic units

C.12

Microform readers

C.13

Facsimile machines (Telecopiers) and

X
X
X
X
X

page scanners
C.14

Cheque processors

X

C.15

Personal computers and workstations

C.16

Single-function printers (SFP)

C.17

Self-service automatic teller machines

X

C.18

Rack-mountable units and rack-

Xb

X
X

Xb

enclosed systems
C.19

CD- and DVD-ROM drives- In case of use in end use equipment

X- In case of sub-assembly

X

C.20

Data projectors

X

C.21

Multi-function printers (MFP)

X

C.22

Hand-held computing and media

X

playback devices
C.23

Digital media recorders and playbackX

units for consumer use
C.24

Large format printers

X

a Reporting emission sound pressure levels from other positions is optional.
b Either operator or bystander positions shall be used. Both operator and bystander

positions may be used if desired. See C.18.1.

© Ecma International 2021

51

Fans, also called “air moving devices”, are often incorporated into the design of ITT equipment to provide airflow
for cooling. To measure such a fan as a component, for example as part of the process of selection for design
use in a computer, refer to ISO 10302-1 and ISO 10302-2.

C.2 Equipment category: Typewriters
C.2.1

Description

This category covers equipment with a keyboard for manual information entry. The information is either keyedin and immediately printed on paper character-by-character (manual typing), or keyed-in and stored for word orline editing with following automatic print-out (interactive operations). Typewriters which are equipped with afull-page storage are considered as typewriters during manual typing and as printers (see C.3) during automatic
print-out on a full page.

C.2.2

Installation

C.2.2.1

GeneralThe typewriter shall be placed in the centre of the top plane of the standard test table. For measurements inaccordance with Clause 7, the measurement surface terminates on the floor. Alternatively, the typewriter may
be placed on a hard reflecting floor. The condition used shall be reported.
C.2.2.2

Type font

If the typewriter allows the use of different type fonts or different type elements, a fine line typestyle (e.g. pica,
elite, and not bold) shall be used with a character pitch of 10 characters per 25,4 mm.
C.2.2.3

Paper

Single sheets of paper of grammage 70 g/m2 to 80 g/m2 in the ISO A4 or equivalent format shall be used unlessthe typewriter is designed for special paper having a different grammage. In this latter case, the special paper
shall be used. Paper shall be inserted in vertical format with the left-hand edge at zero; the leading edge of thepaper sheet shall be fed through to approximately one-third of the paper length, or 100 mm lower than the
trailing edge (see Figure C.1). Paper shall have been stored unpacked and exposed to the environmental
conditions specified in 6.3.2, 7.3.2 or 8.3.2 as applicable, for at least 24 h immediately prior to the test.

100 mm97-0044-A

Figure C.1 — Insertion of single sheet of paper

52© Ecma International 2021

C.2.3Operation

C.2.3.1

Idle mode

The power shall be switched on. Paper shall be inserted in accordance with Figure C.1.
NOTE

If the typewriter has both standby and ready mode, the idle mode corresponds to the standby mode.

If the typewriter has several idle modes, the mode(s) used for measurement shall be reported.
C.2.3.2

Typing mode

C.2.3.2.1

GeneralThe typing mode consists of keying-in the specified character pattern and printing it on paper. Keying-in should
preferably be performed with a suitable robot (see A.2) to simulate manual keystrokes. The noise level due tothe operation of the robot alone shall be at least 6 dB and preferably more than 10 dB below the level ofoperation.
Typing shall start after the paper has been inserted, as specified in Figure C.1 and shall continue for not morethan 100 mm.
NOTE

If a typing robot is not available, manual typing may be used.

C.2.3.2.2

Settings

The following settings, when applicable, shall be used.
a)Impression control: as recommended for a single sheet of paper.

b)Multi-copy control: set for a single sheet.

c)Line spacing: double-line spacing.

d)Margin: 25 mm from the edges; the end-of-line indicator (bell) shall be disconnected.

e)Paperbail rollers: the paperbail rollers shall be set 25 mm from the edges of the paper; the others shallbe equally spaced between.

C.2.3.2.3

Character pattern

The test pattern characters shall be

etnaiv etnaiv etnaiv etnaiv...
and so on until a full printline of approximately 60 characters has been completed.
The single space between each group of six characters is required as part of the pattern. The carriage return
after each line is part of the operation.
NOTE 1
robot.

A maximum of two characters may be replaced by other small letters, if there is a need for adjustment of the

NOTE 2
Should small letters not be available, capital letters may be used instead; equivalent conditions may be selected
for typewriters with non-Latin character sets.

C.2.3.2.4

Operating speed

For manual operations the typing speed shall be five characters per second.

© Ecma International 2021

53

The specified characters shall be keyed in at a rate of five characters per second until the buffer is filled up; amaximum buffer capacity of one printline shall not be exceeded. The stored information shall then be
immediately printed (maximum one line) at the maximum printing speed.

C.2.4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable, during the following operations.
For manual operations: measure during continuous typing over at least three full lines.
For interactive operations: measure during keying-in and printing-out until at least three full lines have been
printed.

54© Ecma International 2021

C.3 Equipment category: Character and line printers
C.3.1

Description

This category covers electronically controlled equipment which prints stored information on paper in steps ofcharacter or line and is not normally keyboard-operated, and the noise output of which depends on the print
pattern. The output may be obtained by means of impact printing (e.g. typebar-, train-, chain- or band-printers,
printwheel, type-element or matrix printers) or by non-impact printing (e.g. electro-erosion or thermal printers)
and excludes inkjet and laser printers.
For inkjet and laser printers, see C.16.
For equipment which offers print and any one or more of the following functions, follow the procedures in C.21
instead of the procedures in C.3:
•
•
•

scan
copy
facsimile

C.3.2
For equipment capable of printing on paper 420 mm or more in width, follow theprocedures in C.24.Installation
C.3.2.1

GeneralFloor-standing printers shall be installed on the hard reflecting floor.
Printers which are normally placed on a special stand or table shall be installed on such a stand on the reflecting
floor. Printers which are placed on an office table or desk and which take paper from, or stack paper on, thefloor, shall, if possible, be placed in the centre of the top plane of the standard test table, using the floor to
support the paper. For such measurements in accordance with Clause 7, the measurement surface terminates
on the reflecting floor.
Table-top printers, which do not use the floor for the paper supply or exit stack, shall be placed on the hardreflecting floor for measurements in accordance with Clause 6 or Clause 7, and on the standard test table formeasurements in accordance with Clause 8.
C.3.2.2

Type style

For printers that support multiple type styles or type elements, a type style typical of normal use, with a pitch of
10 characters per 25,4 mm and 6 lines per 25,4 mm shall be used. If this is not possible, an adjustment as close
as possible to these values shall be chosen. Condensed or extended characters shall not be used.
C.3.2.3

Paper

Either single sheets of paper of grammage 60 g/m2 to 80 g/m2 or continuous, folded or rolled stationery ofgrammage 50 g/m2 to 60 g/m2 shall be used, unless the printer is designed for special paper having a different
grammage. In this latter case, the special paper shall be used. The quantity of paper available for printing shallbe as close as possible to the maximum capacity of the printer. The form width shall be the widest that iscommonly available for the printer and shall be described in the test report. For special applications (e.g. whenthe material to be printed is a passbook or cheque) the material shall be typical for customer usage and shallbe described in the test report.
Paper storage and unpacking shall follow the machine manufacturer's instructions. If there are no such
instructions, paper shall have been stored unpacked and exposed to the environmental conditions specified in
6.3.2, 7.3.2 or 8.3.2 as applicable, for at least 24 h immediately prior to the test.

© Ecma International 2021

55

C.3.3Operation

C.3.3.1

Paper position

For continuous folded or rolled stationery, the paper length fed through the printer shall be at least ten times its
width. For single sheet paper, the print area shall be vertically centred and span at least 60 % of the sheet
length.
C.3.3.2

Idle mode

Idle mode is a steady state condition that occurs after completion of print operation. Printers may have several
idle modes, each with unique noise and duration, for example, step-down or variable speed cooling fan operation.
Idle noise shall be measured after print job completion with the power switch of the printer remaining on. The
idle mode lasting at least one minute with highest noise emissions shall be measured and reported.
The measurement time interval of idle noise measurement shall be in accordance with C.3.4.
C.3.3.3

Operating mode (Print mode)

C.3.3.3.1

GeneralPrinters with single-sheet feeding devices shall be tested in best quality mode. Paper of size ISO A4 or of anequivalent format (portrait) is automatically fed.
Printers with continuous stationery shall be tested in draft mode with maximum paper width.
Printers capable of printing both single sheets of paper and continuous stationery shall be tested in bothconfigurations.
The print mode consists of printing a character pattern specified in C.3.3.3.3.
For graphic printers whose print speed is specified in accordance with ISO/IEC 11160-1 while printing graphic
mode in accordance with ISO/IEC 10561, a second operating mode shall be tested and reported: the second
mode consists of printing the test pattern in ISO/IEC 10561:1999, Annex D.
C.3.3.3.2

Settings

The following settings, when applicable, shall be used.
a)Impression control: as recommended for a single sheet of paper.

b)Multi-copy control: set for a single sheet.

c)Line spacing: double-line spacing and skip 20 mm to 30 mm on each side of the paper fold.

d)Margin: 25 mm from the edges (excluding the perforation strip) except when the printer characteristics
restrict the available line length; in the latter case, typical margin length shall be used and reported.

C.3.3.3.3

Character pattern

The full content of a 40-character test pattern is specified below. The character pattern shall be arranged ingroups of five printed characters followed by five spaces. The position of the pattern should preferably be shiftedby five characters on each line, using an end-around shift over the available line length. The printing area shallbe left-justified and centred vertically. If the line comprises fewer characters, the left-most ones shall be used.

J1YY7

56

2DA90

8S8=2

6AI8Q

B31AJ

5FTOE

PG1TK

X6D-4

© Ecma International 2021

If some of the specified characters are not available, alternative characters of up to 20 % of the characters in
one line may be substituted. For printers which print only non-Latin characters or numerical information arandom set of characters or numbers shall be selected and reported.
NOTE
The number of characters to be printed in one line depends on the printer itself and is specified in Table C.2.
Examples of test patterns are shown in Figures C.2 and C.3.

C.3.3.3.4

Operating speed

The rated speed for which the printer is designed shall be used. If several speeds are provided, the one which
is typical for the majority of the uses shall be selected and described in the test report. Additional conditions
may be specified for special applications and shall be described in the test report.

20 - 30 mm skip

Available Line Length
65 characters

margin
25mm

JIYY7

2DA90
JIYY7

8S8=2
2DA90

JIYY7
5FTOE

JIYY7
5FTOE

B3IAJ

2DA90

5FTOE
6AI8Q

8S8=2

JIYY7

6AI8Q
2DA90

JIYY7

8S8=2
2DA90

JIYY7

8S8=2

JIYY7
5FTOE

2DA90
JIYY7

5FTOE
B31AJ

5FTOE
6AI8Q

8S8=2

JIYY7

6AI8Q
2DA90

JIYY7

8S8=2
2DA90

JIYY7

2DA90

8S8=2

6AI8Q

6AI8Q
2DA90

JIYY7

8S8=2
2DA90

JIYY7

B31AJ

2DA90
JIYY7

5FTOE
B31AJ

6AI8Q

6AI8Q
8S8=2

5FTOE

6AI8Q
8S8=2

B31AJ

8S8=2
2DA90

5FTOE
B31AJ

5FTOE
B31AJ

6A18Q

2DA90

5FTOE

8S8=2
2DA90

B31AJ

JIYY7

B31AJ
6AI8Q

5FTOE

6AI8Q

JIYY7

B31AJ
6AI8Q

8S8=2

6AI8Q

5FTOE

JIYY7
5FTOE

8S8=2

JIYY7

2DA90
JIYY7

B31AJ

8S8=2

5FTOE
B31AJ

8S8=2
2DA90

8S8=2

5FTOE
B31AJ

2DA90

5FTOE
B31AJ

2DA90

8S8=-2

JIYY7

6AI8Q

2DA90
JIYY7

B31AJ
6AI8Q

JIYY7

6AI8Q

6AI8Q
8S8=2

5FTOE
B31AJ

8S8=2

6AI8Q
2DA90

5FTOE
B31AJ

B31AJ

8S8=2
2DA90

5FTOE
6AI8Q

2DA90

8S8=2
JIYY7

B31AJ
6AI8Q

5FTOE
B31AJ

6AI8Q

2DA90
JIYY7

B3IAJ
6A18Q

8S8=2

6AI8Q

2DA90

5FTOE

5FTOE
B31AJ

8S8=2

JIYY7

B31AJ

8S8=2
2DA90

8S8=2

5FTOE

5FTOE
B31AJ

6AI8Q

2DA90

5FTOE
B31AJ

B31AJ
6AI8Q

8S8=2

JIYY7

B3IAJ
6AI8Q

6AI8Q
8S8=2

2DA90

margin
25mm

JIYY7
5FTOE

B31AJ

5FTOE

20 - 30 mm skip

97-0045-A

Figure C.2 — Example of the test pattern for a line length of 65 characters© Ecma International 2021

57

Available Line Lenght
115 characters

margin
25mm

JIYY7

2DA90
JIYY7

858=2

6AI8Q

2DA90
JIYY7

858=2

JIYY7

B31AJ
6AI8Q

2DA90

858=2
2DA90

JIYY7

858=2
2DA90

JIYY7

space as required
to adjust margins

5FTOE
B31AJ

6AI8Q
6AI8Q

2DA90
JIYY7

6AI8Q

2DA90
2DA90
JIYY7

X6D-4
X6D-4
X6D-4

B31AJ

6AI8Q

2DA90

X6D-4

858=2
JIYY7

SFTO2

PGITK
X6D-4
SFTO2
PGITK
X6D-4
6AI8Q
B31AJ
SFTO2
PGITK
X6D-4
6AI8Q
B31AJ
SFTO2
PGITK
X6D-4
858=2
6AI8Q
B31AJ
SFTO2
PGITK
X6D-4
858=2
6AI8Q
B31AJ
SFTO2
PGITK
X6D-4
2DA90
858=2
6AI8Q
B31AJ
SFTO2
PGITK
X6D-4
2DA90
858=2
6AI8Q
B31AJ
SFTO2
PGITK
X6D-4
JIYY7
2DA90
858=2
6AI8Q
B31AJ
5FTOE
PGITK
X6D-4
JIYY7
2DA90
858=2
6AI8Q
B31AJ
5FTOE
PGITK
X6D-4
JIYY7
2DA90
858=2
6AI8Q
B31AJ
5FTOE
PGITK
X6D-4
B31AJ

B31AJ
B31AJ
6AI8Q
2DA90

B31AJ

PGITK
5FTOE

B31AJ
6AI8Q

858=2

X6D-4
PGITK

5FTOE

6AI8Q
858=2

JIYY7
JIYY7
JIYY7

X6D-4
PGITK

5FTOE

858=2
2DA90

X6D-4
PGITK

5FTOE

6AI8Q

2DA90
JIYY7

X6D-4
PGITK

5FTOE
B31AJ

858=2

JIYY7
X6D-4

PGITK

6AI8Q

2DA90

X6D-4
PGITK

5FTOE
B31AJ

858=2

JIYY77
X6D-4

PGITK
SFTO2

6AI8Q

2DA90

X6D-4
PGITK

5FTOE
B31AJ

858=2

JIYY7

PGITK
SFTO2

6AI8Q

2DA90

X6D-4
PGITK

5FTOE
B31AJ

858=2

JIYY7

PGITK

B31AJ

858=2

X6D-4
PGITK

5FTOE

6AI8Q

margin
25mm

X6D-4
PGITK

5FTOE
B31AJ

858=2

JIYY7

PGITK
5FTOE

B31AJ

858=2

20 - 30 mm skip

5FTOE
B31AJ

6AI8Q

B31AJ

2DA90
858=2
6AI8Q
2DA90
858=2
6AI8Q
2DA90
858=2
JIYY7
2DA90
858=2
JIYY7
2DA90
JIYY7
2DA90
JIYY7

20 - 30 mm skip

97-0046-A

Figure C.3 — Example of the test pattern for a line length greater than 110 characters
Table C.2 — Number of characters to be used

C.3.4

Available line length
in characters

Number of characters
to be used

 40

50 % of maximum line length
between margins

40-59

20 characters60-11030 characters 110

40 characters

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable, during the following operations:a) Single-page form: measure during continuous printing over at least 60 % of the page length; if the printerhas an automatic paper feed mechanism, at least three pages shall be printed.
b) Folded stationery: measure during continuous printing over at least three pages.
c) Rolled stationery: measure during continuous printing over a length equal to at least the paper width.
d) Passbook: measure during printing of a single line on the middle pages during a complete operation cyclefrom insertion to ejection (for details see C.17).

58© Ecma International 2021

C.4 Equipment category: Teleprinters
C.4.1

Description

This category covers equipment operating as a send/receive machine basically comprising a keyboard, aprinting unit, a mechanical or electronic send/receive unit (line control unit) and (integrated or optional) a memory
unit (electronic, paper tape punch or reader, magnetic tape, disk or cassette).
Two typical uses are:a) Keyboard operation (when in local or transmission mode): the information is keyed-in by manual typing and
immediately printed on paper and/or stored in the memory.
b) Automatic operation (when in local or on-line mode): the machine prints automatically the information
received from line network or from the memory unit.
When a teleprinter is fitted with an auxiliary unit which produces noise (e.g. paper tape punch/reader, magnetic
tape, disk or cassette), the machine shall be tested with and without the unit in operation.
In some cases a teleprinter can be available in receive-only configuration (without keyboard). That machine isconsidered to be a character or line printer (in accordance with C.3).

C.4.2

Installation

C.4.2.1

GeneralFor keyboard operation of the teleprinter, the general installation conditions for typewriters shall apply (see C.2).
For automatic operation of the teleprinter, the general installation conditions for printers shall apply (see C.3).
C.4.2.2

Paper

Either single sheets of paper of grammage 70 g/m2 to 80 g/m2 or continuous, folded or rolled stationery ofgrammage 50 g/m2 to 60 g/m2 shall be used, unless the printer is designed for special paper having a different
grammage. In this latter case, the special paper shall be used. The quantity of paper available for printing shallbe as close as possible to the maximum capacity of the printer. The form width shall be the widest that iscommonly available for the printer and shall be described in the test report. For special applications (e.g. whenthe material to be printed is a passbook or cheque) the material shall be typical for customer usage and shallbe described in the test report.
If in typical use, multi-part stationery is employed, an additional test with such stationery shall be carried out anddescribed in the test report.
Paper storage and unpacking shall be carried out in accordance with the machine manufacturer's instructions.
If there are no such instructions, paper shall have been stored unpacked and exposed to the environmental
conditions specified in 6.3.2, 7.3.2 or 8.3.2 as applicable, for at least 24 h immediately prior to the test.

C.4.3
C.4.3.1

Operation
Idle mode

The power shall be switched on and paper shall be inserted.
NOTE

If the teleprinter has both standby and ready modes, the idle mode corresponds to the standby mode.

© Ecma International 2021

59

C.4.3.2

Operating mode (Print mode)

For keyboard operation of the teleprinter, the operating conditions specified for keyboards shall apply (see C.5).
For automatic operation of the teleprinter, the operating conditions specified for printers shall apply (see C.3).

C.4.4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable.
For keyboard operation of the teleprinter, the requirements specified for typewriters shall apply (see C.2.4).
For automatic operation of the teleprinter, the requirements specified for printers shall apply (see C.3.4).

60© Ecma International 2021

C.5 Equipment category: Keyboards
C.5.1

Description

This category covers equipment for manual data entry fixed or connected (via a cable or other data transmission
means) to other units, e.g. visual display units, computer console, hand-held calculator, etc.

C.5.2

Installation

Keyboards shall be installed in accordance with the relevant clauses of this Standard, except for measurementsin accordance with Clause 6 or Clause 7. The keyboard may be placed in the centre of the top plane of thestandard test table if required for operation, provided this is reported.

C.5.3
C.5.3.1

Operation
Operating mode (keying-in)

Keying-in shall be performed at a rate of five characters per second.
A suitable robot (see A.2) should be used to simulate manual keystrokes. The noise level due to the operationof the robot alone shall be at least 6 dB and preferably more than 10 dB below the level of operation.
If the keyboard has acoustical feedback, the minimum volume setting shall be used for the test.
NOTE

C.5.3.2

If a typing robot is not available, manual keying-in may be used.

Test patterna) For alphanumeric keyboards, the test pattern shall be as specified for typewriters (see C.2.3.2.3).
b) For numeric keyboards, the test pattern shall be four digits plus function key, the keys selected shall bereported.

C.5.4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable; the requirements specified for typewriters shall apply (C.2.4).

C.5.5

Measurement uncertainty

The measurement uncertainty for determining noise emission levels for keyboard operation has not yet beenverified and may be greater than those given in 6.2, 7.2 and 8.2.

© Ecma International 2021

61

C.6 Equipment category: Copiers (duplicators)
C.6.1

Description

This category covers equipment which can produce one or more copies from a master. Such equipment can becoupled with one or more additional attachments and features. These may be in the form of input, output orinternal devices for a variety of copying needs. Input devices can be in the form of master document loading,handling and registering, or special paper feeders for continuous stationery or label printing. Output devices canbe in the form of copy handlers such as sorters, automatic staplers, stackers and binders. The equipment may
have an internal reversing device(s) for handling two-sided originals and producing two-sided copies; i.e.
automatic duplexing. The copier may also offer full colour copying from full colour masters, or highlight colour
copying.
For equipment which offers print and any one or more of the following functions, follow the procedures in C.21
instead of the procedures in C.6:
•
•
•

scan
copy
facsimile

C.6.2

Installation

C.6.2.1

GeneralDue to the nature of product operation, noise emitted by the copier in operating mode(s) may fluctuatesignificantly with time. Therefore, for this category of equipment, sound power level determination in accordancewith Clause 6 (reverberation test room) may have restrictions to achieve reliable test results: only sound power
level of repeated, or cyclic operations will be determined with the uncertainty stated, and a measurement timeinterval longer than that in free field over a reflecting plane may be required.
Floor-standing copiers shall be installed on the hard reflecting floor.
Copiers which are normally placed on a special stand or table shall be installed on such a stand or table on thereflecting floor. Copiers which are placed on a normal office table or desk and which take paper from, or stack
paper on, the floor, shall, if possible, be placed in the centre of the standard test table, using the floor to support
the paper. For such measurements in accordance with Clause 7, the measurement surface terminates on thereflecting floor.
Table-top copiers, which do not use the floor for the paper supply or exit stack, shall be placed on the hardreflecting floor for measurements in accordance with Clause 6 or Clause 7, and on the standard test table formeasurements in accordance with Clause 8.
The same installation conditions shall be followed when the copier has attachments.
C.6.2.2

Paper

Either single sheets of paper of grammage 60 g/m2 to 80 g/m2 or continuous, folded or rolled stationery ofgrammage 50 g/m2 to 60 g/m2 shall be used, unless the copier is designed for special paper having a different
grammage. In this latter case, the special paper shall be used. The quantity of paper available for copying shallbe as close as possible to the maximum capacity of the copier. The form width shall be the widest that iscommonly available for the copier and shall be described in the test report. For special applications (e.g. whenthe material to be printed is a passbook or cheque) the material shall be typical for customer usage and shallbe described in the test report.
Paper storage and unpacking shall be carried out in accordance with the machine manufacturer's instructions.
If there are no such instructions, paper shall have been stored unpacked and exposed to the environmental
conditions specified in 6.3.2, 7.3.2 or 8.3.2 as applicable, for at least 24 h immediately prior to the test.

62© Ecma International 2021

C.6.3Operation

C.6.3.1

Idle mode

Power shall be switched on and the copier shall be loaded with a suitable paper supply.
C.6.3.2

Operating mode

C.6.3.2.1

GeneralThe nominal speed for which the copier has been designed shall be used; if several speeds are provided, theone which is typical for the majority of the uses shall be employed. The copier shall be adjusted to normal
exposure, and tests shall be carried out without using any reduction/enlargement facility, if provided.
Additional machine set-up conditions may be considered, as follows.
a) Copying without additional attachments
An operation cycle shall consist of continuously copying a single master.
b) Copying with additional attachments: input and output devices
When a copying system combines several features/attachments, a "full system" operation cycle shall comprisethe use of the maximum number of features/attachments allowable at least once. This may include using all thefeatures/attachments on the copier or just some of them. Where all the features/attachments cannot be used
together in one operation cycle, several different operating combinations should be considered. The
combination which is typical of use shall be selected and described in the test report.
C.6.3.2.2
a)Input devices

Automatic loading of originals

An operation cycle shall consist of placing five masters in the device input tray and making five copies of eachmaster. Copies are ejected into a single stationery output tray.
b)

Copying from continuous stationery

An operation cycle shall consist of feeding five pages of continuous stationery through the registering device
and making five copies of each master. Copies are ejected into a single stationery output tray.
C.6.3.2.3
a)Output devices

Sorting

The operation shall start with an empty sorter. An operation cycle shall comprise the registering of one masterand making five copies ejected into five consecutive sorter bins. (Any copies made during additional operation
cycles shall be sorted into the same five consecutive bins.)b)

Stacking

If the copier is equipped with an integral mechanism to separate copy sets generated sequentially, it will
generally be fitted with an input master loading device. The operation cycle shall comprise the placing of fiveoriginals into the device input tray and one copy of each shall be ejected into the stacker.
c)Automatic stapling

Automatic stapling may be provided in the form of a separate output device, or being fitted as integral to a sorteror stacker. Copiers equipped with this device will generally be fitted with an input master loading device. The© Ecma International 2021

63

operation cycle shall comprise the stapling of a set of copies from five masters for a total of five stapled sets,
and ejected into the output tray.
d)

Copying on continuous stationery

An operation cycle shall comprise copying one master on five pages for folded stationery or a 2-m length forrolled stationery.
e)

Auxiliary equipment

If a copier is supplied with an accessory or integral equipment (e.g. a binder), the tests shall be carried out withand without the use of this equipment in the operation cycle.
f)Two-sided copying

Copiers equipped with this feature can either
1) handle two-sided masters and produce from them one-sided or two-sided copies, or2) handle one-sided masters only, and produce from them one-sided or two-sided copies.
Copiers equipped with this device will generally be fitted with an input master loading device.
An operation cycle for type 1) above shall comprise the making of two one-sided copies (one of each of thesides of the master) or one two-sided copy from one two-sided master. This operation cycle is to be repeatedfive times. An operation cycle for type 2) above shall comprise the making of one two-sided copy from two onesided masters, this operation cycle is to be repeated five times.
g)Colour copying

The operation cycle for copiers fitted with this feature shall be the copying from one one-sided full colour master;
one copy is made and automatically ejected into a single stationery output tray.
h)Highlight-colour copying

The operation cycle for copiers fitted with this feature shall be as for monochrome. (Copies should containhighlight-colour from a full text master, e.g. four lines in highlight-colour using the test pattern as specified in
C.3).

C.6.4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least five operation cycles and for at least themeasurement time interval specified in 6.7.2, 7.7.2 or 8.7.2 as applicable.

64© Ecma International 2021

C.7 Equipment category: Card readers and card punches
C.7.1

Description

The category covers equipment which may perform a single function, such as reading the information from, or
punching it into, a punched card. The two functions may also be combined in one machine which allows the useof both functions in one process or to use them separately. The number of cards processed per unit timedepends for readers mainly on the nominal processing speed; for punches it may be significantly influenced by
the total number of columns to be punched per card.
For equipment which performs similar functions such as card duplicating machines, card verifiers, card or
document sorters and collators, code interpreters (with printing features), paper tape readers and punches, thefollowing installation and operating conditions may also be applied.

C.7.2

Installation

The equipment shall be installed in accordance with the relevant clauses of this Standard.

C.7.3
C.7.3.1

Operation
Idle mode

The power shall be switched on and the equipment shall be ready for reading or punching cards.
C.7.3.2

Operating mode (Reading or punching mode)If equipment of this category is capable of both reading and punching in one process, the operating mode shallconsist of both punching and reading cards as specified below. If equipment allows only the use of thesefunctions separately, the operating mode shall be punching.
The specified character pattern shall be read from, or punched into and/or read from, each card; approximately
40 % of the maximum number of columns (usually 80) shall contain information. The specified character patternshall be arranged in groups of five characters followed by five spaces:
J1YY7

C.7.4

2DA90

8S8=2

6AI8Q

B31AJ

5FTOE

PG1TK

X6D-4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable during processing of a random card deck of at least 10 cards.

© Ecma International 2021

65

C.8 Equipment category: Magnetic tape units
C.8.1

Description

This category covers equipment for writing on, and reading from, a magnetic tape wound on reels or within acassette or a cartridge. A unit may contain one or more separately operable tape drives.

C.8.2

Installation

Installation shall be in accordance with the relevant clauses of this Standard.

C.8.3

Operation

C.8.3.1

Idle mode

C.8.3.1.1

Idle unloaded mode

The power shall be switched on and the tape shall not be in the tape path.
C.8.3.1.2

Idle loaded mode

The power shall be switched on and the tape shall be loaded and the equipment shall be ready to receive andrespond to control line commands to any drive. In multiple drive units, all drives shall be loaded and ready.
C.8.3.2

Operating modes

C.8.3.2.1

General

One of the modes specified below shall be used as applicable.
In multiple drive units, only one drive shall be in operating mode; all other drives shall be in the idle loaded mode.
C.8.3.2.2

Read/Write mode

Start, read or write, stop — with command timing for capstan (or equivalent) operation as follows.
Capstan on-time, in milliseconds, is set at the time needed to pass 130 mm of tape at the rated tape speed, s,
defined as
130 mm
ms
sm s

(C.1)

rounded to the nearest millisecond.
The off-time is equal to 0,7 to 1 times the on-time.
NOTE
For a magnetic tape of 12,7 mm width, 130 mm of tape corresponds to a block length of 4 096 bytes at 32 bpmm.
Higher densities should use correspondingly larger block sizes, such that the total on-time for all density machines will beapproximately equal. At 63 bpmm, use a block length of 8 192 bytes; at 246 bpmm, use a block of 32 768 bytes.

C.8.3.2.3

Streaming mode

Logical forward run while writing.

66© Ecma International 2021

C.8.4

Measurement time interval

The time-averaged sound pressure level shall be measured, for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable, for at least twenty consecutive start/stop operations in accordance with
C.8.3.2.2 or streaming operations in accordance with C.8.3.2.3.

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C.9 Equipment category: Disk units and storage subsystems
C.9.1

Description

This category covers equipment for writing on, and reading from, one or more rotating magnetic or optical disks.
Disks may be removable or non-removable. Magnetic disks may be flexible or rigid. A unit may contain one ormore separately operable disk drives.
NOTE

C.9.2

For read-only optical disk drives (e.g. CD- and DVD-ROM drives), see C.19.

Installation

Installation shall be in accordance with 5.1 and 8.5. Disk units which form part of a personal computer, rackmounted equipment, or hand-held computing and media playback device shall be tested in accordance with
C.15, C.18 or C.22 as appropriate. Disk units which are tested as sub-assemblies shall be installed as subassemblies in accordance with 5.1.7.

C.9.3

Operation

C.9.3.1

Idle mode

C.9.3.1.1

Idle readyDisk(s) shall be loaded, power on, unit ready to receive and respond to control link commands with spindle up
to speed and read/write heads in track-following mode.
For systems having a single drive, the drive shall be as described above. For systems with multiple drives or forstorage subsystems, the number of drives that are simultaneously operable by the host CPU shall be operated
as specified above. All other drives shall be in the idle mode typical of normal use for the system.
C.9.3.1.2

Idle standby

If power-saving modes are available, such modes may be tested and if tested shall be described in the report.
C.9.3.2

Operating mode

For units having a single drive, the drive shall be operating as described below.
For units with multiple drives, or for storage subsystems, the number of drives that are simultaneously operable
by the host CPU shall be operated as specified below. All other drives shall be in the idle mode, typical of normal
use for the system.
Randomly select a cylinder/track to be sought in such a way that every cylinder/track has equal probability of
being selected. (If the drive incorporates an algorithm to perform seeks in a more efficient non-random order,
then this algorithm may be used. In this case the drive should be given a command or commands to read or
write a random selection of files, and the drive algorithm will decide the order in which the commands are
executed. The file length shall be adjusted to achieve the seek rate defined below). Seek to that track, thendelay for a time period tD achieving the required seek rate ns within  10 % in accordance with the following
formula:ns = 0,4 / (tT + tL)(C.2)

tD = 1,5 tT + 2,5 tL

(C.3)

where
ns

68

is the average seek rate, expressed in seeks per second;© Ecma International 2021

tT is the manufacturer's published time, in seconds, to seek from one random track to another without
including rotational latency;tL

is the time, in seconds, for the drive to rotate by half a revolution.

Repeat the seek process. No other intentional delay while selecting the cylinder is allowed. The average numberof seeks per second along with the seek algorithm shall be reported with the acoustical data.
If the drive is operating in a system and if the system is not capable of achieving the required seek rate, thedrive shall be operated at the maximum seek rate achievable.
If the drive is operating in a multiple drive system in a Redundant Array of Inexpensive Disks (RAID) environment,
the drive shall be operated at the maximum seek rate achievable compatible with the system RAID level in use.

C.9.4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable.
NOTE
Acoustical “beating” in multi-drive arrays can occur over periods of time that are long relative to the requirementsof 6.7.2, 7.7.2 or 8.7.2. The resulting variation in sound pressure level at microphone positions can have a significant effecton the variability of A-weighted sound power level determined for the equipment. This variability can be reduced byincreasing the measurement time to include several beating cycles.

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C.10 Equipment category: Visual display units and terminals
C.10.1

Description

This category covers equipment which displays information on a screen, and which may be equipped with akeyboard for information entry. The keyboard may be fixed to the display unit or connected to it by means of acable or other means of data transmission.
The units in this category may emit significant noise in the 16 kHz octave band. For equipment which emits
sound in the 16 kHz octave band, the procedures specified in ECMA-108 for reporting sound power levels shallbe used (see Table 4).

C.10.2

Installation

Installation shall be in accordance with the relevant clauses of this Standard.

C.10.3C.10.3.1

Operation
Idle mode

The power shall be switched on and the equipment shall be in a steady-state condition, with air-moving device(s),if any, running and the representative pattern shall be displayed on the screen. The keyboard shall not be
operated.
Preliminary tests should be run to determine if the emissions are significantly sensitive to the pattern displayedon the screen. If so, a pattern representative of maximum emission values for a typical user shall be determined.
If not, the representative pattern shall be defined to be a full character set displayed on the screen and repeateduntil all positions on the screen are used. The representative pattern used shall be documented and reported.
C.10.3.2

Operating mode (Typing mode), if applicable

The typing mode consists of keying-in the information specified for keyboards (see C.5).
C.10.3.3

Power saving mode

If power saving modes are available, such modes may be tested in addition to the modes defined in C.10.3.1,
described and reported.

C.10.4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable.

70© Ecma International 2021

C.11 Equipment category: Electronic units
C.11.1

Description

This category covers equipment such as processors, electronic memories and controllers, containing only
electronic circuits, power supplies but no moving mechanical parts except those associated with cooling.

C.11.2

Installation

Installation shall be in accordance with the relevant clauses of this Standard.

C.11.3C.11.3.1

Operation
Operating mode

Operate in the steady-state condition with normal load on all cooling devices, power supplies, and distributed
power supply elements. For electronic units, the idle and operating modes are deemed to be the same.
C.11.3.2

Power saving mode

If power saving modes are available, such modes may be tested in addition to the modes defined in C.11.3.1,
described and reported.

C.11.4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable.

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C.12 Equipment category: Microform readersC.12.1

Description

This category covers equipment to display micro-images. Microform readers may differ from each other,
depending on the different types of microforms to be used, such as microfiche, aperture cards and rollfilm.

C.12.2

Installation

Installation shall be in accordance with the relevant clauses of this Standard.

C.12.3C.12.3.1

Operation
Idle mode

The power shall be switched on and the equipment shall be ready to display.
C.12.3.2

Operating mode

The microform shall be inserted and the micro-image adjusted and displayed.
The following two operations may be performed with partial or full automation.
a)Equipment for microfiche and aperture cards: the micro-image shall be adjusted in two diagonal corners
by moving its support; an image shall be kept stationary.

b)

Equipment for rollfilm with a full reel of microfilm loaded into the device: the image approximately in the
middle of the film shall be sought and adjusted; the rollfilm shall be transported automatically.

The operation used during the test shall be described in the test report.

C.12.4

Measurement time interval

The time-averaged sound pressure level shall be measured for a minimum of three operation cycles and for atleast the measurement time interval specified in 6.7.2, 7.7.2 or 8.7.2 as applicable.

72© Ecma International 2021

C.13 Equipment category: Facsimile machines (telecopiers) and page scanners
C.13.1

Description

C.13.1.1

Facsimile machines

This category covers equipment operating as a send/receive machine, basically comprising a numeric keyboard,a paper feeding device, a scanner, a print unit and an electronic send/receive control unit. Telecopiers are used
for transmitting text, drawings and graphic information via public transmission networks.
C.13.1.2

Page scanners

This category covers equipment operating as a scanner which detects text, drawing and graphical informationfrom full sheets of paper and comprises a paper feeding device and a scanning mechanism.
For equipment capable of print and any one or more of the following functions, follow the procedures in C.21
instead of the procedures in C.13:
•
•
•

scan
copy
facsimile

C.13.2

Installation

C.13.2.1

GeneralFloor-standing machines shall be installed on the hard reflecting floor.
Machines which are normally placed on a special stand shall be installed on such a stand on the reflecting floor.
Machines which are placed on an office table or desk and which take paper from, or stack paper on, the floor,
shall, if possible, be placed in the centre of the top plane of the standard test table, using the floor to support
the paper. For such measurements in accordance with Clause 7, the measurement surface terminates on thereflecting floor.
Table-top machines, which do not use the floor for the paper supply or exit stack, shall be placed on the hardreflecting floor for measurements in accordance with Clause 6 or Clause 7, and on the standard test table formeasurements in accordance with Clause 8.
C.13.2.2

Paper

For sheet stationery operations, sheet stationery of grammage 60 g/m 2 to 80 g/m2 shall be used in accordancewith machine manufacturer’s instructions. A4 sheets shall be used whenever possible; otherwise, a sheet size
characteristic of typical use shall be used.
For continuous stationery operations, continuous folded or rolled stationery of grammage 50 g/m2 to 60 g/m2
characteristic of typical use shall be used in accordance with machine manufacturer’s instructions.
Paper storage and unpacking shall follow the machine manufacturer's instructions. If there are no such
instructions, paper shall be unpacked and exposed to the environmental conditions specified in 6.3.2, 7.3.2 or
8.3.2 as applicable, for at least 24 h immediately prior to the test.
The paper tray shall be filled as close as possible to its maximum capacity.

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73

C.13.3

Operation

C.13.3.1

Idle mode

Idle mode is a steady state condition that occurs after completion of sending, receiving or scanning. Facsimile
machines and page scanners may have several idle modes, each with unique noise and duration, for example,
step-down or variable speed cooling fan operation.
Idle noise shall be measured after send, receive or scan job completion with the power switch of the machineremaining on. The idle mode lasting at least one minute with highest noise emissions shall be measured andreported.
The measurement time interval of idle noise measurement shall be in accordance with C.13.4.
C.13.3.2

Operating modes

C.13.3.2.1

GeneralMachine operations shall use the pattern of Figure C.8. For monochrome printers, the monochrome mode shallbe tested. For colour capable machine with different colour and monochrome speeds, both colour andmonochrome modes shall be tested. For colour capable Machine with identical colour and monochrome speeds,
the colour mode shall be tested.
The pattern in Figure C.8 is based on JBMS-74-1:2005[17].

NOTE

The default resolution and the default speed shall be used for all functions, whether monochrome or colour.
Operation of facsimile machine or page scanner shall begin after warm-up periods have expired and all moving
parts are located in their home position.
C.13.3.2.2

Operating modes

Send and receive operations shall be measured and reported for facsimile machines. Printing of transmission
receipts shall be included if such printing is the default for send operation. Scan operation shall be measured
for page scanners.
C.13.3.2.3

Single sheet machines

One-sided sheet operation shall be measured unless two-sided operation is the default, in which case two-sided
operation shall be measured.
C.13.3.2.4

Continuous folded or rolled stationery machines

One-sided operation shall be measured. A page shall consist of the test pattern of Figure C.8 scaled to fit to the
maximum printable or scannable area of the machine, as appropriate to the operation.

C.13.4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable.
••

Single-sheet machines (equipped with feeding device): at least three (3) sheets
Continuous folded or rolled stationery machines: at least one (1) page

These measurement time intervals are applicable to both send and receive operations of facsimile machines
and scan operations of page scanners.

74© Ecma International 2021

C.13.5

Reporting

Noise emissions of idle and default operations shall be reported. Noise emissions of operations other than thedefault operations may be reported. The description “idle” shall accompany noise emissions reported for idle.
The following shall accompany the noise emissions reported for operations other than idle:•

Operation:•

Rendering: “mono” or “colour”•

Quality: “best”, “normal”, “draft”, etc.

•

Sidedness: "simplex" or "duplex"•

Input method:"ADF" or “flatbed”•

Media: format(“folded”, “rolled” or “sheet”), “paper size” and “grammage”“scan”, " facsimile send", “facsimile receive”© Ecma International 2021

75

C.14 Equipment category: Cheque processors
C.14.1

Description

The category covers equipment which may perform a single function such as printing (or encoding) information
onto cheques, reading information from cheques, printing lists, storing/retrieving information from a flexible disk
cartridge, or sorting cheques.

C.14.2

Installation

C.14.2.1

GeneralThe equipment shall be installed in accordance with the relevant clauses of this Standard.
C.14.2.2

Paper

C.14.2.2.1

Cheque stock

Typically, a large variety of cheque sizes and grammage of paper are used. To allow a standard method, thefollowing specification defines the properties of the cheques to be used.
a)Length: 140 mm to 160 mm.

b)

Height: 70 mm to 90 mm.

c)Grammage: 90 g/m2 to 100 g/m2.

C.14.2.2.2

Printer paper

If in typical use, multiple-part stationery is employed, an additional test with such stationery shall be performed
and reported.

C.14.3C.14.3.1

Operation
Idle mode

The power shall be switched on and the equipment ready for use (i.e. stand-by mode).
C.14.3.2

Operating mode

When a cheque-processing system combines several features, a full system operation cycle shall comprise theuse of each of those features at least once as described below under their respective operation cycle.
a)Reading

Random alpha-numeric data shall be read from the cheques in this mode and any additional operations which
typically form part or are a result of this mode shall be performed (e.g. autofeed, listing, storing on flexible disk
cartridge and sorting cheques). Repeated read cycles shall be performed at a rate typical of that expected inuse.
b)Printing (or encoding)Equipment of the type described in this category will in some cases contain a number of print mechanisms
within one piece of equipment. The equipment shall be operated in a manner most typical of the expected use,with all print mechanisms operating in the proper sequence. Any additional operation which typically form partor result from this mode of operation shall be performed (e.g. autofeed, listing, storing on flexible disk cartridge

76© Ecma International 2021

and sorting cheques). The information to be printed by each type of printing mechanism (where appropriate) isdefined in Table C.3.
Repeated print cycle shall be performed at a rate typical of that expected in use.
c)Printing (listing)Repeated cycles of the character pattern shown below shall be printed at a rate typical of that expected in use.
The full content of a 40-character pattern is given; if the line contains fewer characters, the left-most ones shallbe used.
The characters shall be arranged in groups of five followed by five spaces and each subsequent line shall berotated five spaces to the right.
J1YY7

2DA90

8S8=2

6AI8Q

B31AJ

5FTOE

PG1TK

X6D-4

Any additional operations which typically form part or are a result of this mode shall be performed.
d)Storing/retrieving from disk

Consecutive seeks shall be carried out to a random track. Any additional operations which typically form part orare a result of this mode shall be performed.
e)Sorting

The cheques shall be sorted sequentially from the lowest numbered pocket to the highest numbered pocket andthis sort pattern repeated as necessary for the measurement time interval.
Table C.3 — Cheque processor printer types and corresponding print patterns
Printertype

C.14.4Characters to be printed
Print details

Encoder*0000000085124* (amount field only)

Programmable endorser

J1YY7

Fixed endorser

any character

2DA90

8S8=2

6AI8Q

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable. For the operating mode, the measurement time interval shall be at leastthat of eight complete operation cycles.

© Ecma International 2021

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C.15 Equipment category: Personal computers and workstations
C.15.1

Description

This category covers small systems such as personal computers, workstations and word processors, which
include a keyboard, visual display unit, and a processor unit which itself may contain combinations of one ormore flexible, rigid and/or optical disk drives, magnetic tape units or printers.
For equipment which emits sound in the 16 kHz octave
ECMA-108 for sound power levels shall be used (see Table 4).

C.15.2band,

theprocedures

specifiedinInstallation

The constituent units of the system may be tested individually and reported accordingly. In this case theinstallation conditions are as in 5.1, 8.5 and the relevant clauses of this annex.
Alternatively the equipment may be tested as a complete system. In this case for the measurement of soundpower levels, the equipment shall be mounted on the hard reflecting floor and the setup used recorded.
For the measurement of emission sound pressure levels at operator position, the separate enclosures which
comprise the system shall be arranged in a set-up that is typical of actual use. Solely table-top systems shallbe installed on the standard test table with all equipment front faces parallel to the front edge of the table. A “flat”
table-top system (i.e. the system’s width is greater than its height) shall be centred left to right on the test table(Figure C.4a).
A small tower table-top system (system’s height is greater than its width) shall be placed 0,05 m from the rightedge of the test table (Figure C.4b). If a monitor is placed on the table alongside the small tower, then a gap of
0,05 m shall be left between the monitor and the small tower. The keyboard shall be 0,05 m from the front edgeof the table. If the system has a detachable keyboard, the system shall be 0,30 m from the front edge of thetable. The operator position microphone then is 0,25 m in front of the keyboard or 0,50 m from a system with adetachable keyboard in accordance with 8.6.2.
Notebook computers shall be centred left to right on the test table and placed 0,05 m from the front edge of thetest table. It is recommended that the screens of notebook computers be adjusted to be perpendicular to an
imaginary line passing from the microphone at the operator’s position to the centre of the screen.
If parts of the system are floor-standing and others are table-top, the floor-standing equipment shall be installedon the floor to the operator’s right of the test table and oriented such that the front face of the equipment isparallel to the front edge of the table and even with the table and in the same vertical plane (Figure C.4c).
Equipment adjacent to the table shall be spaced 0,075 m away from the vertical plane formed by the edge ofthe top of the table. The table-top equipment shall be installed on the test table with all front faces parallel to thefront edge of the table. For non-parallelepiped equipment, the orientation shall represent typical use and shallbe documented in detail. If the processor is tested individually without the presence of keyboard or monitor, theprocessor shall be installed in accordance with this paragraph and Figure C.4a, C.4b, or C.4c.
All-in-one systems, where the display, processor, and storage functions are contained within a single unit, shallbe placed on the test table in accordance with Figure C.4c and Figure C.4d; in the case of Figure C.4c, the allin-one system shall be placed at the monitor position. The screen of an all-in-one system shall be aligned
according to Figure C.4d or as close thereto as allowed by the design of the unit. The distance to the operator
position shall be measured from the farthest forward portion of the system when the screen is aligned according
to Figure C.4d.

78© Ecma International 2021

Centre line

0,05m

0,25m

Test table

Desktop
processor

0,3m

Monitor

0,5m

Keyboard

X

Microphone at
operator position

Figure C.4a — Installation for system comprising “flat” table-top equipment

Centre line

0,05m
0,05m

0,3m

Keyboard

Small tower

Monitor

0,25m

0,5m

0,05m

Test table

Microphone at
operator position

Figure C.4b — Installation for a small tower table-top system© Ecma International 2021

79

Centre line

0,05m

0,25m

Test table

0,3m

0,5m

Keyboard

Floor standing
processor

MonitorX
0,075mMicrophone at
operator position

Figure C.4c — Installation for a floor standing system or all-in-one system (at the monitor location)

P3

10° ± 3°0,50 m0,25 mFigure C.4d — Screen angle for all-in-one system

80© Ecma International 2021

C.15.3

Operation

C.15.3.1

GeneralOperating conditions as required by Section 5.3 are described in this section. Installation shall follow Section
8.5. The modes of operation were designed to represent typical use of the whole system.
NOTE 1The operating modes in previous versions of this standard were defined in terms of operation of the individual
subsystems rather than the whole system. Methods to measure such subsystems are still available in this standard. For
equipment with flexible disk drives and rigid disk drives as specified in C.9. For combinations of rigid and flexible disk drives,
the operating mode is defined as one rigid disk drive operating, and all other drives idle as specified in C.9. For equipmentwith magnetic tape units as specified in C.8. For equipment with built-in character and line printers as specified in C.3; For
equipment with single-function printers as specified in C.16. For equipment with optical drives as specified in C.19.

In addition to the idle mode specified in C.15.3.2, at least two (2) of the other operating modes as described
C.15.3.3 shall be measured for the system under test. The operating modes selected shall represent the mostcommon intended use cases for the system under test. The tested modes shall be reported, and workload
details shall be documented as outlined in sections C.15.3.2 and C.15.3.3. The workloads in section C.15.3.3
represent typical use for that operating mode, and they are relatively steady state in nature. If any of the specified
workloads in sections C.15.3.3 are not officially natively supported for the system under test, a custom workloador script may be developed and used for that workload. Such a workload shall be similar in tasks, operations
and sequence to the specified workloads, and the procedure shall be documented in the test report. Any suchcustom workload and/or scripts shall be made available for acoustic testing and verification purposes.
For each of the operating modes in section C.15.3.3, an acoustical steady state should be attained before
measurement. This generally coincides with thermal steady state, i.e., when air mover speed is stable.
Monitoring of acoustical output, air mover speeds and temperature sensors may be required to ensure such a
steady state is attained.
NOTE 2

Generally, steady state may be attained by the third consecutive application of the operating mode workload.

Because system performance and acoustic noise levels are correlated, the system power management andperformance settings shall match the settings used to measure and report system performance. If noperformance testing was done, factory defaults shall be used. If multiple factory default power management
configurations exist, or if non-matching settings are used, the system power management and performancesettings, as selectable by a consumer, shall be selected and reported.
C.15.3.2

Idle mode

Power shall be switched on, the equipment shall be in a steady-state condition, and the user shall have logged
in with the screen displayed in its default settings and the system is ready to respond to user input.
C.15.3.3

Operating mode(s)C.15.3.3.1 Web browsing mode
From idle operating mode, a web browsing application shall completely fill the display, not including any
operating system control bar or menu bars, and by use of automated scripting, navigate to multiple popular
websites. The browser shall have at least 6 tabs open with a mix of content, including news, social media,
media streaming and a marketplace site. The script shall simulate user scrolling activity while viewing web
content through short intermediate scroll inputs to mouse buffer, interspersed with clicks on links within pages,
in a continuous loop to allow thermal stabilization of system on standard test table in chamber prior to acoustic
measurement. Measurement is to be taken with web browsing automation script active. Per section 5.3, audio
playback shall be muted for measurement of noise emissions.
NOTE 3
Examples of websites include CNN, New York Times and Washington Post for news, Facebook and Twitter forsocial media, YouTube for media streaming, and Amazon for a marketplace.

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C.15.3.3.2 Office productivity
For this operating mode, the most recent version of PCMark or SYSmark Productivity suite shall be used. The
test report shall indicate which of these workloads, and what version, was used. After running the suite multiple
times, the workload shall be re-started and then the acoustical measurement is taken.
C.15.3.3.3 Media content creation
For this operating mode, the Cinebench R20 “all cores”, SYSmark Creativity or Prime 95 suite shall be used.
The test report shall indicate which of these workloads, and what version, was used. After running the suite
multiple times, the workload shall be re-started and then the acoustical measurement is taken.
C.15.3.3.4 Power user & gaming
For this operating mode, the 3DMark Timespy, Unigen Heaven or Luxrender suite shall be used. The test reportshall indicate which of these workloads, and what version, was used. After running the suite multiple times, theworkload shall be re-started and then the acoustical measurement is taken.

C.15.4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable. Per section 5.3, the duration of the workload should be such that themeasurement concludes before the workload ends.

82© Ecma International 2021

C.16 Equipment category: Single-function printers (SFP)
C.16.1

Description

This category covers equipment which produces printed output from computers and includes but is not limited
to inkjet and laser printers. SFP usually are graphic capable, may be duplex capable, and may have peripheral
equipment such as staplers, binders, cutters, envelope feeders, sorters, and special paper feeders.
For equipment capable of impact printing or non-impact printing other than inkjet printers, follow the proceduresin C.3 instead of the procedures in C.16. See C.3.1 for a description of impact and non-impact print
technologies.For teleprinters, see C.4.For equipment capable of print and any one or more of the following
functions, follow the procedures in C.21 instead of the procedures in C.16:
•
•
•

scan
copy
facsimile

For equipment capable of printing on paper 420 mm or more in width, follow the procedures in C.24.

C.16.2

Installation

C.16.2.1

GeneralFloor-standing printers shall be installed on the hard reflecting floor. Printers which are normally placed on a
special stand or table shall be installed on such a stand or table on the reflecting floor. Printers which are placedon a normal table or desk and which take paper from, or stack paper on, the floor, shall, if possible, be placedin the centre of the top plane of the standard test table, using the floor to support the paper. For suchmeasurements in accordance with Clause 7, the measurement surface terminates on the reflecting floor.
Table-top printers, which do not use the floor for the paper supply or exit stack, shall be placed on the hardreflecting floor for measurements in accordance with Clause 6 or Clause 7, and on the standard test table formeasurements in accordance with Clause 8.
C.16.2.2

Paper

For sheet stationery operations, sheet stationery of grammage 60 g/m2 to 80 g/m2 shall be used in accordancewith machine manufacturer’s instructions. ISO A4 sheets shall be used whenever possible; otherwise, a sheet
size characteristic of typical use shall be used.
For continuous stationery operations, continuous folded or rolled stationery of grammage 50 g/m 2 to 60 g/m2
shall be used in accordance with machine manufacturer’s instructions. For printers designed for specificapplications, the paper shall be in accordance with C.24.2.2.
Paper storage and unpacking shall follow the machine manufacturer's instructions. If there are no such
instructions, paper shall be unpacked and exposed to the environmental conditions specified in 6.3.2, 7.3.2, or
8.3.2 as applicable, for at least 24 h immediately prior to the test.
The paper tray shall be filled as close as possible to its maximum capacity.

C.16.3C.16.3.1

Operation
Idle mode

Idle mode is a steady state condition that occurs after completion of print operation. Page printers may haveseveral idle modes, each with unique noise and duration, for example, step-down or variable speed cooling fan
operation.

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Idle noise shall be measured after print job completion with the power switch of the printer remaining on. The
idle mode lasting at least one minute with highest noise emissions shall be measured and reported.
The measurement time interval of idle noise measurement shall be in accordance with C.16.4.
C.16.3.2

Operating mode (Print mode)

C.16.3.2.1

GeneralPrinters shall be operated using the pattern of Figure C.8. For monochrome printers, the monochrome modeshall be tested. For colour capable printers with different colour and monochrome speeds, both colour andmonochrome modes shall be tested. For colour capable printers with identical colour and monochrome speeds,
the colour mode shall be tested.
The pattern in Figure C.8 is based on JBMS-74-1:2005[17].

NOTE

For printers whose maximum paper width capability is less than the A4 sheet width of 210mm, the print patternof Figure C.8 shall be uniformly scaled to span the print area width. The print area width is the paper width
reduced by the left and right margins, each of which may span up to 10% of the paper width.
The nominal default resolution and the nominal default speed shall be used for all functions, whether
monochrome or colour.
One-sided printing shall be measured unless two-sided printing is the default, in which case two-sided printing
shall be measured.
C.16.3.2.2

Operation cycle with features

When a printing system combines several features, a full system operation cycle shall comprise the use of eachof the features at least once as described under the respective operation cycle.
a)Sorter

The sorting operation shall start with an empty sorter. An operation cycle shall comprise the sorting of one pagein one bin. Pages printed during additional cycles shall be sorted into consecutive bins.
b)Stacking

If the printer is equipped with an accessory or integral mechanism to separate jobs generated sequentially, an
operation cycle shall comprise two jobs and print one page for each of them.
c)Auxiliary equipment

If the printer is supplied with auxiliary equipment (e.g. a mechanism for cutting continuous forms), the tests shallbe carried out with and without the use of such equipment in the operation cycle.

C.16.4

Measurement time interval

For each set-up the time-averaged sound pressure level shall be measured, for at least the measurement timeinterval specified in 6.7.2, 7.7.2 or 8.7.2 as applicable, and as follows:
•

•

84

Single sheet printers: at least three sheets (three pages) for one-sided simplex printing; at least three
sheets (six pages) for two-sided duplex printing. Ramp-up and ramp-down motion before and after
repetitive print cycles shall not be measured.
Printing with auxiliary features: at least one (1) sheet.

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C.16.5

Reporting

Noise emissions of idle and default operations shall be reported. Noise emissions of operations other than thedefault operations may be reported. The description “idle” shall accompany noise emissions reported for idle.
The following shall accompany the noise emissions reported for operations other than idle:•

Operation:•

Rendering: “mono” or “colour”•

Quality: “best”, “normal”, “draft”, etc.

•

Sidedness: "simplex" or "duplex"•

Media: format (“folded”, “rolled” or “sheet”), “paper size” and “grammage”“print”© Ecma International 2021

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C.17 Equipment category: Self-service automatic teller machines
C.17.1

Description

The category covers equipment mainly used in banking environments and provides various services tocustomers, such as cash dispense, funds transfer between accounts, account balance inquiry, balancestatement issuing and envelope deposit.
Depending on the purpose of the equipment, a variety of different functions can be performed and combined in
one machine. Typical examples for operating modes are specified in C.17.3; it is not assumed that these
conditions apply to all cases, therefore, the test conditions used shall be described in the test report.

C.17.2

Installation

The equipment shall be installed in accordance with the relevant clauses of this Standard.

C.17.3Operation

C.17.3.1

Idle mode

The power shall be switched on and the equipment shall be ready for use.
C.17.3.2

Operating mode

The operating mode which is typical for average customer usage shall be defined and reported. For someequipment, examples are defined as follows:a)Money dispenser

Operation comprises card insertion, key-in personal identification number (PIN), task selection (e.g. cash issue),selection of amount of money, issue card, open cash gate, issue cash, issue receipt and close cash gate.
b)

Passbook operation

Operation comprises−

insert passbook, read magnetic stripe data, key-in PIN, print one line in passbook, write and verify
magnetic stripe data and issue passbook, orinsert passbook, read magnetic stripe data, key-in PIN, task selection (e.g. cash issue), selection ofamount, write and verify magnetic stripe data, issue passbook and issue cash.

−c)Banking information print-out

Operation comprises check card insertion, key-in PIN, task selection (e.g. statement of account), issue card,
print output and issue output.
d)Cash envelope deposit

Operation comprises card insertion, key-in PIN, task selection (e.g. cash deposit), key-in amount of deposit,
insert envelope into depository device, remove card and receipt.

C.17.4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable. For the operating mode, an average value shall be determined for at least
three typical transactions, during which manual access may be needed, which however shall not be intentionally
delayed.

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C.18 Equipment category: Rack-mountable units and rack-enclosed systems
C.18.1

Description

This category covers both rack-mountable units (see 3.1.13) and rack-enclosed systems (see 3.1.14).
Rack-enclosed systems take several forms, including single- and dual-rack enclosed systems. A system of rackmountable units provided without rack/enclosure may be tested as individual units or as a rack-enclosed system.
When tested as a rack-enclosed system, the individual units shall be assembled into a rack/enclosure according
to manufacturer instructions.
For rack-enclosed systems that are available in more than one configuration of rack-mountable units, theparticular configuration to be measured is usually governed by the purposes of the test and is thus not specified
in this Standard. However, if the configuration has not been otherwise specified prior to the test, and if practical,
it is recommended that a typical configuration be measured as a minimum, possibly supplemented by otheridentifiable configurations (e.g., minimum configuration or maximum configuration, or both). In any event, theconfiguration(s) of the system shall be described in the test report in sufficient detail to uniquely identify the unit
under test.
For rack-mountable units and rack-enclosed systems, either the bystander or operator sound pressure level
shall be measured and reported, see Table C.1. Operator positions are described in C.18.2.1 and C.18.2.2.
Bystander positions and calculations are described in 8.6.3 and 8.8.3, respectively. Both the bystander andoperator sound pressure levels, as well as sound pressure levels for multiple operator positions, may bereported if desired; see C.18.7.
NOTE
Operator sound pressure level is representative of the noise experienced by personnel next to a rack-mountable
unit or rack-enclosed system equipment for installation, configuration, maintenance, or service [77]. Measurement andreporting of operator sound pressure level is recommended when concern over noise level close to the equipment exists orwhen personnel approaching the equipment are likely to interact physically with the equipment.

C.18.2

Installation

In general, the requirements of 5.1.1 and 5.1.5 shall be met. Specific installation requirements are given below.
Rack-mountable units that are not designed for a specific rack-enclosed system (e.g., units that may be used
in a variety of industry-standard racks) shall be tested outside of a rack and treated as “sub-assemblies” for the
purposes of this Standard (see 3.1.12 and 5.1.7).
NOTE 1
In addition to the above requirements, such units may optionally be tested installed in a rack in accordance withthe following paragraphs.

Rack-mountable units that are designed as part of, or intended to be installed in, a specific rack-enclosed systemshall be tested in that specific rack enclosure. The unit shall be installed as specified by the manufacturer orrequestor of the test, including the vertical position in the rack enclosure. If no position is specified, the unit shallbe mounted at approximately the same height as that required for sub-assemblies (see 5.1.7). If the specificrack enclosure is fully- or partially-enclosed, then all other positions in the rack shall either be filled with blankrack panels or populated with unpowered rack-mountable units. If the specific rack enclosure is of an openframe design, then filling the empty positions in the rack is not required and the unit may be installed alone in
the rack. Only the rack-mountable unit under test shall be powered on, and only the noise emission levels of
this unit shall be reported, together with its position in the rack enclosure.
NOTE 2
Individual rack-mountable units should be installed no lower than the minimum height for subassemblies (see5.1.7) [77].

If the above rack-mountable unit requires power, cooling, or other facilities from other units in the rack enclosurefor its operation, then one of the following approaches shall be used.

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(i) The rack-mountable unit shall be measured along with the other units required for its operation and the results
reported as the overall noise emission levels for the units taken together. The report shall describe the units thatwere tested together.
(ii) The rack-mountable unit shall be measured along with the other units required for its operation and theresults reported as an upper bound for the noise emission levels for the particular unit under test (e.g., when
the levels of the auxiliary units are much lower than the unit under test). The report shall describe the units thatwere tested together.
(iii) If practical, first the auxiliary units shall be measured together by themselves with the rack-mountable unit
under test powered off, and second the measurement shall be repeated with the rack-mountable unit powered
on. Appropriate computations (e.g., similar to the corrections for background noise in ISO 3741) shall be
carried out to “subtract out” the noise level of the auxiliary units, and the results reported as an estimate forthe noise emission levels for the particular unit under test. The report shall describe the units that were tested
together and the procedure used to determine the estimated noise levels of the unit under test.
When measuring operator sound pressure level of rack-enclosed systems or rack-mountable units tested inrack-enclosed systems, any access doors or covers shall be opened or removed according to the
manufacturer’s instructions for servicing while the equipment remains operable. Any extendible components,
assemblies, or subsystems on slide rails or equivalent shall be fully retracted.
C.18.2.1

Operator positions for rack-mountable units

Rack-mountable units, including units treated as a subassembly according to 5.1.7, are tested in a 0.25m
vibration isolating test stand or a rack-enclosed system, see Figure C.5.
Front and rear operator positions apply to rack-mountable units. The operator positions are centred across thewidth of the rack- mountable unit at a horizontal distance of 0,50 m  0,03 m from the nearest face of the unit
(not the vibration isolating test stand or the rack) and vertically at the median height of the unit above the floor.
See Figure C.5.

88

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Top
view

Side
view

a) On test standb) In rack-enclosed system

Figure C.5 — Front (F) and rear (R) operator positions for rack-mountable units (RMUs)

C.18.2.2

Operator positions for rack-enclosed systems

Standing and crouched operator positions apply to each accessible face of a rack-enclosed system. The
operator positions are centred across the width of the rack-enclosed system at a horizontal distance of
0,50 m  0,03 m from the nearest face of the rack-enclosed system (not the rack-mountable units within thesystem). The standing operator position is 1,50 m  0,03 m above the floor. The crouched operator position
1,00 m  0,03 m above the floor. See Figure C.6.
When multiple rack-enclosed systems are side by side, operator positions apply to each rack-enclosed system,
as shown for the dual-rack configuration in Figure C.7.
NOTE: The number of operator positions for each rack-enclosed system ranges from two to eight, depending on the numberof accessible faces. Rack-enclosed systems are typically accessible from their front and/or rear faces and sometimes froma side face.

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Figure C.6 — Standing (S) and crouched (C) operator positions for rack-enclosed systems

Top
view

Side
view

a) Single rackb) Dual rack

Figure C.7 — Examples of rack-enclosed systems containing rack-mountable units (RMUs) showing
the standing (S) and crouched (C) operator positions

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C.18.3

Operation

In general, the requirements of 5.3 shall be met. Specific operating requirements are given below for thefollowing modes of operation.
C.18.3.1

Idle mode

The power shall be switched on, and all rack-mountable units shall be in idle mode ready to receive commandsignals from the system CPU.
C.18.3.2

Operating mode

The operating modes for the equipment covered by C.18.1 are defined as follows. One or more of the following
operating modes shall be used as applicable:−

For equipment with rigid and flexible disk drives as specified in C.9;−

For equipment with magnetic tape units as specified in C.8;−

For equipment with built-in character and line printers as specified in C.3; equipment with single-function
printers as specified in C.16;−

For equipment with a central processing unit: the operating mode shall be the typical workloads
described below to best represent the noise levels that a majority of customers may encounter. The
central processing unit may include microprocessors, memory modules and add-in cards (for example,
graphics card), herein referred to as “subsystems” of the central processing unit. If operation of aparticular subsystem below does not result in an increase in fan speed(s) or an otherwise increase innoise level, that subsystem does not need to be tested. Operating of each subsystem shall follow:
1) Microprocessors subsystems: Typical workload of all microprocessors shall be taken as half of the
maximum load using microprocessor centric performance testing applications. If multiple
microprocessors are included in a central processing unit, this typical workload shall be evenly
distributed across all microprocessors, as far as practical.

NOTE 1
If load-scalable microprocessor-centric performance testing applications, such as Specpower, MaxPower or
ThermNow are used, then the acoustic measurement should be done at the 50 % of the maximum load setting as specified
above. However, if load non-scalable applications, such as Linpack and Prime95 are used, the load between maximum andidle may be modulated to approximate the 50% typical workload condition. Modulation should be adjusted such that a
steady-state noise emission condition is measured.

2) Memory subsystem: A memory subsystem consists of all memory modules within the central
processing unit, whether installed on a motherboard, or via multiple riser cards. Typical workload forthe memory subsystem shall be taken as half of the attainable platform performance bandwidth of thememory subsystem, with bandwidth equally distributed over all memory modules, as far as practical.
NOTE 2
Attainable platform performance bandwidth may be obtained by running a load-scalable memory performance
application at the maximum performance bandwidth setting. The acoustical testing should then be done at 50 % of thismaximum performance bandwidth setting.

3) Other identified subsystems: The workload for any other subsystem of the central processing unit notdescribed above shall be representative of the typical end-use workload for that subsystem andclearly defined and documented in the report, if tested.
−

For equipment with other components not listed above, the operating mode shall be representative oftypical end-use operation for that component and clearly defined and documented in the report.

NOTE 3
Measurements on individual disk drives should be made at the seek rate typical of the multiple-drive
configuration if system limitations do not allow the seek rate specified in C.9. This is necessary so as not to overestimate
the system noise emission levels as calculated in accordance with C.18.5 from individual measurements.

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C.18.4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable, and as further required in this annex for the operation of the rack-mountable
units.

C.18.5 Calculation of the system A-weighted sound power level and system A-weighted
emission sound pressure level from individual rack-mountable unit sound levels
The system A-weighted sound power level shall be calculated using the following formula:
n

10

i =1

LWA, sys = 10 lg

0,1LWAi

dB
(C.4)

where
LWA,sysis the system A-weighted sound power level, in decibels;

LWAi

is the A-weighted sound power level of the i-th rack-mountable unit installed in a rack
enclosure;n

is the number of rack-mountable units.

The system A-weighted emission sound pressure level shall be calculated using the following formula:
n

10

i =1

L pA, sys = 10 lg

0,1L pAi

dB
(C.5)

where
LpA,sysis the system A-weighted emission sound pressure level, in decibels;

LpAi

is the A-weighted emission sound pressure level of the i-th rack-mountable unit installed in a
rack enclosure;n

is the number of rack-mountable units installed and tested.

NOTE
The calculations in C.18.5 may be used by enclosures other than “rack enclosed systems”, such as, a server,
PC, or storage arrays. In this case the individual units are “sub-assemblies” instead of “individual rack-mountable units” in
C.18.5.

C.18.6 Calculation of A-weighted sound power level and A-weighted emission soundpressure level for low noise level rack-mountable units
In some cases the noise level of rack-mountable units may be within 6 dB of the background noise level which
would preclude an accurate value if measured individually. In this case enough identical rack-mountable units
shall be tested and measured in the enclosure, so that the noise level of the n rack-mountable units is sufficiently
greater than the background noise level (it may be convenient to test the maximum number allowed).
The rack-mountable unit A-weighted sound power level shall be calculated from the following formula:
LWA,s= LWA,sn − 10 lg n dB

(C.6)

where

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LWA,sis the averaged individual rack-mountable unit A-weighted sound power level, in decibels;

LWA,snis the total A-weighted sound power level for n identical installed rack-mountable units, indecibels;nis the number of rack-mountable units installed and tested.

The rack-mountable unit A-weighted emission sound pressure level shall be calculated from the following
formula:
LpA,s = LpA,sn − 10 lg n dB

(C.7)

where
LpA,s

is the rack-mountable unit A-weighted emission sound pressure level, in decibels;

LpA,snis the total A-weighted sound pressure level for n identical installed rack-mountable units, indecibels;nis the number of rack-mountable units installed and tested.

NOTE
The calculations in C.18.6 may be used by enclosures other than “rack enclosed systems”, such as, a server,
PC, or storage arrays. In this case the individual units are “sub-assemblies” instead of “individual rack-mountable units” in
C.18.6.

C.18.7

ReportingAll reported operations shall be clearly described. Sound power level and either bystander sound pressure oroperator sound pressure shall be reported. If desired the bystander and operator sound pressure levels may
both be reported.
For bystander sound pressure level, the mean emission sound pressure level shall be reported. Bystander
microphone positions and calculations are defined in 8.6.3 and 8.8.3, respectively.
For operator sound pressure level, the highest sound pressure level measured at the operator positions
described in C.18.2.1 and C.18.2.2 shall be reported, as applicable to rack-mountable units or rack-enclosed
systems. If desired, the sound pressure level at multiple operator positions may additionally be reported.
NOTE It is recommended to report the highest operator sound pressure level at each accessible face.

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C.19 Equipment category: CD-and DVD-ROM drives
C.19.1

Description

The category covers equipment for reading electronic information from a rotating read-only optical disk (forexample, CD-ROM or DVD-ROM) or other optical media operated in a substantially sequential access manner.

C.19.2

Installation

C.19.2.1

GeneralInstallation shall be in accordance with 5.1 and 8.5. A drive which forms part of a personal computer or rack
mounted equipment shall be installed in accordance with C.15 or C.18 as appropriate. A drive which is tested
as a sub-assembly shall be installed as a sub-assembly in accordance with 5.1.7.
C.19.2.2Media

The unbalance Ud of test media, defined in the following formula, shall be 2,5 g·mm ± 10 %.
Ud = md · r

(C.8)

where
md

is the mass of the disk, in grams (g),ris the distance between the centre of gravity and the geometrical centre of the disk, inmillimetres (mm)NOTE 1More detailed and specific information on the disk media is available in Reference [30]. Since (1) the
measurement of unbalance is not an objective of this Standard, (2) test media satisfying this requirement is commerciallyavailable from several sources2, and (3) it is not possible for most users of this Standard to adjust media to meet the criteria
for unbalance, while they can only measure the value, it is recommended to use a dedicated test media which has theunbalance specified above.
NOTE 2This media unbalance requirement is based on several considerations as follows: C.1 requires that the operation
be “typical of average end use”. Conditions are to be “specified with a view to facilitate the operation of the equipment andto enhance the reliability of the acoustical measurements”. The disk unbalance of 2,5 g-mm  10 % is specified as “typicalof average end use” and is also consistent with reliable acoustical measurements, since this degree of unbalance avoids
causing some drives to slow down. Technical details justifying this are contained in Reference [31].

C.19.3C.19.3.1

Operation
Idle mode

Except for short-duration transients, idle modes are considered non-rotational and inaudible. Therefore
measurement of the idle mode is not required.
In cases where the drive under test incorporates cooling assemblies for its normal operation, the cooling noise
shall be measured as a part of noise of the drive.
C.19.3.2

Operating mode

For units having a single drive, the drive shall be operating as described below.

2 For instance, Almedio, 2-32-13 Sakae-cho, Higashimurayama, Tokyo, Japan, offers such disks (http://www.almedio.co.jp).

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For units with multiple drives the number of drives that are simultaneously operable by the host CPU shall be
operated as specified below. All other drives shall be in the idle mode, typical of normal use for the system.
Start sequential read at the inner radius of the disk (or media) such that the disk spins continuously at the fastest
speed sustainable with the specified media. Repeat the above read process until the measurement time interval
specified in C.19.4 elapses.

C.19.4

Measurement time interval

The time-average sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable.

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C.20 Equipment category: Data projectors
C.20.1

Descriptions

This category covers equipment driven by a computer input signal, for making an image projection, and by using
a built-in light valve (see Definition C.1) or other technology.
This category does not cover equipment that is intended or designed for permanent outdoor installation.
The equipment may also have video input, but equipment having only video input is excluded.
Definition C.1

light valve
a sub-system or key component of a projector which builds up an optical image from that
produced electrically within the image displaying element, by casting light from another lightsourceNOTE

Still-projectors for film media (e.g. slide, OHP etc.) are covered by ISO 10996 [5].

C.20.2

Installation

C.20.2.1

GeneralThe equipment shall be installed in accordance with the relevant clauses of this Standard (i.e., 5.1 and 8.5 asapplicable).
If the projector under test can make both front and rear screen projection (see Definitions C.2 and C.3), front
screen projection configuration is applicable.
Definition front screen projection
image projected on the audience side of a light-reflecting screen
Definition C.3

rear screen projection
image projected through a light transmitting screen to the audience side of the screen

NOTE
Definitions C.2 and C.3 above are consistent with those specified in IEC 61947-1:2002 and IEC 61947-2:2001,
respectively.

C.20.2.2

Warm up time

The equipment shall be operated for a sufficient period of time before proceeding with the acoustical test toallow the temperature to stabilize. If this time is unknown, the equipment shall be operated at least 30 min before
the acoustical test.
C.20.2.3

Special considerations for test personnel safety

Due to the nature of these products, a data projector emits a strong light beam. Therefore, it is necessary to
pay special attention to protect the test personnel’s eyes.
For the purposes of this Standard, it is strongly recommended to switch the lamp off while positioning the
microphones.

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C.20.3

Operation

C.20.3.1

GeneralFor the operation of this category of equipment (including idle mode), the lamp on or off are expressions basedon light valve technology. For projectors based on other technology, the corresponding operations are to be
defined in a similar manner to those contained below.
C.20.3.2

Idle mode

A stable condition in which the equipment is powered, but the lamp is not on. Transient periods, such as that
immediately after switching the lamp off, are excluded. For some projectors, operation during idle mode may
not be possible in which case noise measurements are not required.
C.20.3.3

Operating mode

A stable condition in which the equipment is powered with the lamp on. For the purposes of this Standard, if thenoise emissions are dependent upon the image projected, the equipment shall project the image of Figure A.1
of IEC 61947-1:2002 or of Figure A.1 of IEC 61947-2:2001, as applicable.
NOTE

IEC 61947-1 and IEC 61947-2 are applicable to projectors with fixed and variable resolution respectively.

Transient periods, such as those immediately after switching the lamp on, are excluded .

C.20.4

Measurement time interval

The time-averaged sound pressure levels shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable.

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C.21 Equipment category: Multi-function printers (MFP)
C.21.1

Description

This category covers equipment capable of print and any one or more of copy, scan and facsimile functions
defined in C.3, C.6, C.13 and C.16. MFP may be monochrome or colour capable, or both, and may be duplex
capable. MFP may have an automatic document feeder (ADF) for loading masters and output devices such as
stackers, sorters, staplers, binders and cutters, which are either included in the standard product configurationor are optionally purchased.
For equipment capable of printing on paper 420 mm or more in width, follow the procedures in C.24.

C.21.2

Installation

C.21.2.1

GeneralThe MFP shall be installed in accordance with its standard product configuration. Optionally purchased
peripheral devices are not considered to be part of the standard product configuration.
Floor-standing MFP shall be installed on the hard reflecting floor.
MFP which are normally placed on a special stand or table shall be installed on such a stand or table on thereflecting floor. MFP which are placed on a normal table or desk and which take paper from, or stack paper on,
the floor, shall, if possible, be placed in the centre of the top plane of the standard test table, using the floor to
support the paper. For such measurements in accordance with Clause 7, the measurement surface terminates
on the reflecting floor.
Table-top MFP, which do not use the floor for the paper supply or exit stack, shall be placed on the hard reflecting
floor for measurements in accordance with Clause 6 or Clause 7, and on the standard test table formeasurements in accordance with Clause 8.
C.21.2.2

Paper

For sheet stationery operations, the paper of grammage 60 g/m2 to 80 g/m2 shall be selected in accordancewith the machine manufacturer's instructions. ISO A4 sheets shall be used whenever possible; otherwise, asheet size characteristic of typical use shall be used.
Paper storage and unpacking shall follow the machine manufacturer’s instructions. If there are no such
instructions, paper shall be unpacked and exposed to the environmental conditions specified in 6.3.2, 7.3.2 or
8.3.2 as applicable, for at least 24 h immediately prior to the test.
The paper tray shall be filled as close as possible to its maximum capacity.

C.21.3C.21.3.1

Operation
Idle mode

Idle mode is a steady state condition that occurs after completion of print or copy operation. MFP may haveseveral idle modes, each with unique noise and duration, for example, step-down or variable speed cooling fan
operation.
Idle noise shall be measured after print or copy job completion with the power switch of the MFP remaining on.
The idle mode lasting at least one minute with highest noise emissions shall be measured and reported.
The measurement time interval of idle noise shall be in accordance with C.21.4.

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C.21.3.2

Operating modes

C.21.3.2.1

GeneralMFP operations shall use the pattern of Figure C.8. For monochrome printers, the monochrome mode shall betested. For colour capable MFP with different colour and monochrome speeds, both colour and monochromemodes shall be tested. For colour capable MFP with identical colour and monochrome speeds, the colour modeshall be tested.
The pattern in Figure C.8 is based on JBMS-74-1:2005[17].

NOTE

The nominal default resolution and the nominal default speed shall be used for all functions, whether
monochrome or colour.
Operation of MFP shall begin after warm-up periods have expired and all moving parts are located in their home
position.
C.21.3.2.2

Output devices

Standard output devices shall be included in the standard product configuration for measurement.
Output devices shall be empty at the start of the measured operation.
Standard output devices representative of typical use shall be operated. If several output devices are standard,
the combination of output devices representative of typical use shall be used. Output devices are used asfollows:•••

Binder (Stapler): An operation involves the binding (stapling) of a set of pages.
Sorter: An operation involves ejecting pages into consecutive sorter bins.
Stacker: An operation involves ejecting pages into a stacker.

C.21.3.2.3

Modes of operation

At least, one mode shall be chosen and measured according to manufacturer’s instruction. If there are no such
instructions, at least mode a) shall be measured.
The remaining mode(s) are optional and may be measured at the discretion of the equipment manufacturer.
a) Print
One-sided printing shall be measured unless two-sided printing is the default mode, in which case two-sided
printing shall be measured.
b) ADF copy
ADF copy shall be measured only if scanning and printing are simultaneous over some part of the copy operation.
For ADF equipped MFP that simultaneously scan masters and print copies, the making of one-sided copies
from one-sided masters shall be measured unless two-sided copying is the default, in which case default twosided copying mode shall be measured. In either case, one copy shall be made for each master.
c) ADF scan
The ADF shall be operated while scanning. The registration of one-sided masters shall be measured unless
two-sided registration is the default, in which case two-sided scanning shall be measured. The default scan
resolution and the default electronic output format shall be used.

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99d) Flatbed copy
The making of a single one-sided copy from a single master involves placing a master on the flatbed of the MFP
with cover closed against the master. The flatbed copy operation includes all events related to registration of
the master and generation of a single copy, from start of registration to delivery of the copy.
e) Flatbed scan
The making of a single one-sided scan from a single master involves placing the master on the flatbed of the
MFP with cover closed against the master. The flatbed scan operation includes all events related to registrationof the master, from start to finish.
f) Miscellaneous operations
Various operations may be measured at the discretion of the test requestor. Examples include:•

Alternative media, e.g. heavy paper, envelopes and transparencies•

Duplex printing, copying and scanning•Standard output devices not representative of typical use•

Optional (non-standard) output devices•

Optional (non-standard) input devices like high capacity input trays

C.21.4

Measurement time interval

The time-averaged sound level shall be measured at least for the measurement time interval specified in 6.7.2,
7.7.2 or 8.7.2 as applicable for the modes of operation described in C.21.3, as follows.
•

Print, ADF copy, and ADF scan: at least three sheets (three pages) for one-sided simplex operations; atleast three sheets (six pages) for two-sided duplex operations. Ramp-up and ramp-down motion before
and after repetitive cycles shall not be measured.

•

Flatbed copy and Flatbed scan: at least one (1) sheet. When a flatbed operation involving one sheet
does not fulfill the measurement time interval, additional flatbed operations shall be measured such thatthe sum of the durations of the individual operations fulfills the required measurement time interval.
Flatbed noise emission levels, L are computed as follows:k 1
L = 10 lg   Ti  10 0,1Li  Ttot i =1


(

)

(C.9)

where
Ti and Li are the duration and noise emission level (sound power level or emission sound pressure level)of i-th individual flatbed copy operation,kis the number of repeated flatbed operations (i = 1, 2, …k), which satisfies the measurement
time interval requirement of 6.7.2, 7.7.2 or 8.7.2 as applicable,

Ttot

is the total measurement time interval of repeated flatbed operations; Ttot =

k

T .
i

i =1

•

100

Miscellaneous operations involving output devices: five (5) sets of “N” sheets, where “N” is at least threeand enough to fulfill the required measurement time interval.

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C.21.5

Reporting

Noise emissions of the idle and default operations shall be reported. Noise emissions of operations other thanthe default operation may be reported. For the idle operation, only the operation description “idle” need beprovided. For operations other than idle, the following information shall accompany the noise emissions:•Operation:•

Rendering: “mono” or “colour”•

Quality: “best”, “normal”, “draft”, etc.

•

Sidedness: “simplex” or “duplex”•

Input method:•

Output devices: “binder”, “stapler”, “sorter”, “stacker”, etc.

•

Media: format (“folded”, “rolled” or “sheet”), “paper size” and “grammage”“print”, “copy” or “scan”“ADF”, “flatbed”, “high-capacity”, etc.

Colour(https://www.ecma-international.org/wp-content/uploads/colour_pattern.pdf)
Figure C.8 — Monochrome/colour pattern for noise emission testing of MFP (not to scale)

NOTE

Figure C.8 was previously Figure C.5b.

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C.22 Equipment category: Hand-held computing and media playback devices
C.22.1

Description

This category covers hand-held equipment for computing, office productivity software, internet browsing, digital
media playback, and similar functions. Devices may run a general purpose operating system or be optimized
solely for one or more of the functions listed above. Devices may be held in one or both hands during typicalusage, and do not have a keyboard large enough for touch-typing.
Ultra-mobile PCs (UMPC), hand-held MP3 players, tablet or slate devices, and hand-held digital video players
come under the scope of this category. Hand-held optical disk players do not come under the scope of thiscategory.
Equipment lacking both air-moving devices and hard disk (rotating media) storage need not be measured orreported.

C.22.2

Installation

The device shall be installed in accordance with 5.1.6, 8.5 and 8.6.1.

C.22.3Operation

C.22.3.1

GeneralOperation of the equipment shall be in accordance with 5.3 and 8.5 for the following modes of operation.
Intentional sound, such as music, speech, or user interface sounds, shall not be included in equipment
operations.
C.22.3.2

Idle mode

Power shall be switched on, and the equipment shall be in a steady-state condition, including thermal equilibriumwith the environment. Disk drives shall be in the idle ready mode as defined in C.9.3.1.1, and the standard userinterface shall be displayed on the screen. Any air-moving device(s) shall be running as needed to cool thesteady-state condition.
If power saving modes are available, such modes may be tested in addition to the above idle mode, and shallbe described in the test report, if measured.
C.22.3.3

Operating mode(s)One or more of the following operating modes shall be used where applicable. Noise due to keyboard operation
shall not be included. Any air-moving device(s) shall be running as needed to cool the operating mode at steadystate.
a) Equipment with rigid disk drives as specified in C.9.3.2.
b) Running a typical workload. For computing devices this may be running office productivity software or
rendering web pages. For digital media playback devices, this may be playing a video file (if capable of doingso) or audio file, but with no intentional sound output.

C.22.4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable.

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C.23 Equipment category: Digital media recorders and playback units for consumeruse
C.23.1

Description

This category covers systems used to record digital media contents in the form of audio visual signals from acommercial source such as (but not limited to) cable TV or satellite TV providers. Such systems can be referred
to as Personal Video Recorders (PVR), Digital Video Recorder (DVR), or Time Shifting Entertainment System.
Such systems can, and usually do incorporate some form of digital storage device for recording of programminge.g. HDD, SSD, or other future storage methods. When use of storage sub-systems and cooling fans isincorporated, the unit shall be tested as in 5.1, 8.5 and the relevant clauses of this annex.
For equipment which emits sound in the 16 kHz octave band, the procedures specified in ECMA-108 for soundpower levels shall be used (see Table 4).

C.23.2

Installation

The constituent units of the system may be tested individually and reported accordingly. In this case theinstallation conditions are as in 5.1, 8.5 and the relevant clauses of this annex.
Alternatively the equipment may be tested as a complete system. In this case for the determination of soundpower levels, the equipment shall be mounted on the hard reflecting floor and the setup used recorded.

C.23.3Operation

C.23.3.1

GeneralOperation of the equipment shall be in accordance with 5.3 and 8.5 for the following modes of operation.
C.23.3.2

Idle mode

Power shall be switched on, the equipment shall be in a steady-state condition, with air-moving device(s) running,
if any, optical drives, if any, in idle mode as in C.19, system operating disk drives in a “pass through” manner(neither explicitly recording nor explicitly playing back).
C.23.3.3

Operating mode(s)One or more of the following operating modes shall be used where applicable.
a)Equipment with rigid disk drives:
1)

Operating condition shall be determined in accordance with C.9.3.2 where ns shall be: 12Mb/s (HD)or 2Mb/s (SD), divided by the number of user data bits per track on the HDD multiplied by the total
number of read/write video streams.
If complete information for the previous paragraph is not available, the user can determine thenumber of tuners incorporated within the system. Once determined, simulate explicit recording of
the same number of media streams as there are tuners while simultaneously explicitly playing backone media stream or however many media streams are the system’s advertised capacity.

2)b)With air-moving device(s) running

Equipment with optical drives.
1)

Operate optical drives as described in C.19.

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2)
c)

With air-moving device(s) running

Equipment with other parts with operating modes not described above: name and operating conditions
shall be included in the report if a measurement is performed.

C.23.4

Measurement time interval

The time-averaged sound pressure level shall be measured for at least the measurement time interval specified
in 6.7.2, 7.7.2 or 8.7.2 as applicable.

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C.24 Equipment category- Large format printers (LFP)
C.24.1

Description

This equipment category covers electronically controlled office equipment capable of printing pre-recorded
information on sheet or roll paper stationery 420 mm or more in width. Some LFP may be capable of scan, copy
or facsimile operations in addition to printing.
NOTE 1420 mm is the smaller dimension of ISO A2 size paper

NOTE 2Equipment not suitable for the office is excluded. Examples include equipment producing noxious fumes, or
equipment requiring electrical, burn, or entrapment hazard safety training.
NOTE 3For character printers and line printers, see C.3; for teleprinters, see C.4; forsingle-function printers, see C.16;
for non-LFP multi-function printers, see C.21.

C.24.2

Installation

C.24.2.1

GeneralFloor-standing printers shall be installed on the hard reflecting floor. Printers which are normally placed on a
special stand shall be installed on such a stand on the reflecting floor. Printers which are placed on an officetable or desk and which take paper from, or stack paper on, the floor, shall, if possible, be placed in the centreof the top plane of the standard test table (see A.1), using the floor to support the paper. For such measurementsin accordance with Clause 7, the measurement surface terminates on the reflecting floor.
Table-top printers, which do not use the floor for the paper supply or exit stack, shall be placed on the hardreflecting floor for measurements in accordance with Clause 6 or 7 and on the test table for measurements inaccordance with Clause 8.
For the purposes of declaring A-weighted emission sound pressure level in accordance with ECMA-109, thebystander positions are applicable.
C.24.2.2

Paper

Paper shall be representative of the typical use of the LFP. Unless otherwise specified, gloss and/or semi-gloss
paper of grammage of 200-300 g/m2 shall be used for LFP designed for graphics applications, and plain paperof grammage of 60-90 g/m2 shall be used for LFP designed for CAD applications.
The width of the paper shall match the maximum width capability of the LFP.
When roll paper is used, the amount of paper on the roll shall be at least one-half of the amount of paper on a
new roll of paper. When sheet paper is used, the paper cartridge shall be at least half full.
Paper storage and unpacking shall be carried out in accordance with manufacturer's instructions. If there areno such instructions, paper shall have been stored unpacked and exposed to the environmental conditions
specified in 6.3.2 or 7.3.2 whatever appropriate, for at least 24 h immediately prior to the test.

C.24.3C.24.3.1

Operation
Idle mode

Idle mode is a steady state condition that occurs after completion of print or copy operation. Several idle modes
may be present, each with unique noise and duration, for example, step-down or variable speed cooling fan
operation.

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Idle noise shall be measured after print or copy job completion with the power switch remaining on. The idle
mode lasting at least one minute with highest noise emissions shall be measured and reported.
The measurement time interval of idle noise shall be in accordance with C.24.4.
C.24.3.2

Operating modes

C.24.3.2.1

GeneralOperations shall use the pattern of Figure C.8 scaled according to Section C.24.5 and Figure C.8.
Default quality operations shall be measured. For monochrome LFP monochrome operations shall be tested.
For colour capable LFP colour operations shall be tested, and monochrome operations shall also be tested ifcolour and monochrome operating speeds differ.
Print speed and print quality shall be at default settings for the type of paper type used.
C.24.3.2.2

Modes of operation

At least one mode shall be chosen and measured according to manufacturer’s instructions. If there are no such
instructions, at least mode a) shall be measured.
The remaining mode(s) are optional and may be measured at the discretion of the equipment manufacturer.
a) Print
One-sided continuous printing shall be measured unless two-sided printing is the default mode, in which casetwo-sided continuous printing shall be measured.
b) Miscellaneous operations
Various operations may be measured at the discretion of the test requestor. Examples include:
•
•
•
•
•
•

C.24.4

Alternative stationery, e.g. heavy paper, envelopes and transparencies
Duplex printing, copying and scanningStandard output devices not representative of use
Optional (non-standard) output devices
Optional (non-standard) input devices like high capacity input trays
Event combinations such as combined printing and paper cutting

Measurement time interval

The time-averaged sound pressure level shall be measured at least for three cycles of operation and theminimum duration specified in 6.7.2, 7.7.2 or 8.7.2 as applicable for the modes of operation described in C.24.3,
as follows.
For LFP having a print carriage moving perpendicular to advancing paper, a paper advance and the associatedcarriage stroke(s) across the width of the paper comprise an operating cycle. For such LFP the print carriage
may make one or two strokes depending on the sequence designed into the LFP.
For LFP without a moving carriage, for example printers with inkjets spanning the paper, steady-state printingof one sheet comprises an operating cycle. Other associated events like loading, cutting, and ejecting of paper
may be excluded from the measurement; however, these events may be included in the measurement when
their removal is not feasible because they are simultaneous or close together in time. The measurement shallexclude ramp-up behaviour at the start of a print job and shall exclude ramp-down behaviour at the end of a
print job.

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When an operation does not fulfil the measurement time interval, additional operations shall be measured suchthat their summed durations fulfil the required measurement time interval. In this case, noise emission levels L
are computed using formula C.9 with the word “flatbed” replaced by the appropriate operation.
NOTE
Paper loading, cutting, and ejecting tend to be less repeatable than the events comprising the operating cycle
and therefore may be omitted to increase measurement repeatability. Paper eject tends to be especially non-repeatable dueto the nature of the paper impacts against floor or printer structure that follow cutting, particularly for carriage equipped LFP.

C.24.5

Colour pattern scaling

The print pattern of Figure C.8 shall be uniformly scaled to span the print area width shown in Figure C.9. The
print area width is the media width reduced by a maximum 30 mm left margin and a maximum 30mm rightmargin.

C.24.6

Reporting

Noise emissions of the idle and default operations shall be reported. Noise emissions for operations other thanthe default operations may be reported. For the idle operation, the description “idle” shall be provided. For
operations other than idle, the following information shall be reported:••••

Media: Paper grammage weight
Operation:“print”, “copy” or “scan”
Rendering:“mono” or “colour”
Quality: “best”, “normal”, “draft”, etc.

Outer line of each
paper size

Print area width

Print area

Left margin

Right margin

Max 30 mm

Max 30 mm

Figure C.9 — Scaling of the Figure C.9 print pattern to the print area

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Annex D(informative)
Identification and evaluation of prominent discrete tones

D.1 ScopeThis Annex specifies two methods for determining whether or not noise emissions contain prominent discrete
tones by reference to ECMA-418 “Psychoacoustic metrics for ITT equipment - Part 1 (prominent discrete tones)”,which gives such details. They are referred to the tone-to-noise ratio method and the prominence ratio method.
The application of this Annex is optional and arbitrarily additional to the requirements of Clause 8. However,when applied, discrete tones occurring at any frequency within the one-third-octave bands having centre
frequencies from 100 Hz to 10 000 Hz (i.e., discrete tones between 89,1 Hz and 11 220 Hz) shall be evaluatedby either of the two methods in this Annex.
NOTE
At the discretion of the user of this Standard, both methods may be applied to same discrete tone of interest. In
such a case, it is noted that the evaluation results of the two methods are considered individual.

D.2 Information to be reported
For each discrete tone that has been identified as prominent in accordance with this Annex, the following
information shall be recorded:a)the frequency, ft, in hertz, of the discrete tone;b)details of the method used to evaluate the discrete tone (tone-to-noise ratio or prominence ratio), together
with a reference to ECMA-418-1 including its publication date and edition;c)

if the tone-to-noise ratio method was used, the tone-to-noise ratio, LT, in decibels or if the prominence
ratio procedure was used, the prominence ratio LP, in decibels;d)if the noise emissions under investigation include more than one identified prominent discrete tone, thefrequency of each tone, and either LT or LP for each tone.

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Annex E(informative)
Background information on the method formerly used for the detectionof impulsive noise

Since its publication of the 1st edition of 1981 September, this Standard had provided an objective test methodfor determining whether the noise emissions are impulsive in character, or not. The method had relied on timeweighting I specified in the well-known sound level meter’s International Standard, IEC 61672-1 (or IMPULSE
mode of its predecessor standards).
By the update of IEC 61672-1:2013, however, the technical specifications of time-weighting I have been
removed. It is also noted that, by the previous update of IEC 61672-1 in 2002, this IEC standard, in its Annex C,
mentioned the following:“Various investigations have concluded that time-weighting I is not suitable for rating impulsive sounds withrespect to their loudness. Time-weighting I is also not suitable for assessing the risk of hearing impairment, nor
for determining the “impulsiveness” of a sound. Because of the possibility of obtaining misleading results,
time-weighting I is not recommended for the purposes described above.”
Therefore, it was a matter of time for the specification to be withdrawn. Eventually, the method of this Annex E
became unable to maintain, and the technical contents have been removed. The 12th Edition ECMA-74 is thelast edition to contain Annex E with an objective method for the detection of impulsive noise using the timeweighting I.
For such historical reasons and also, however, for the possibility of future development of another method for
impulsive noise detection, this Annex E remains, but, the title was revised, accordingly.

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Annex F(informative)
A hearing model approach to calculate psychoacoustic parameters

The reader is referred to ECMA-418 “Psychoacoustic metrics for ITT equipment - Part 2 (models based onhuman perception)”. ECMA-418-2 Clause 5 describes the hearing model approach for determining the specificloudness of a sound. This result is used as basis for further psychoacoustic analyses. Noise data recorded per
ECMA-74 are used to implement the psychoacoustic methods of ECMA-418-2.

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Annex G(informative)
Identification and evaluation of prominent tonalities using a
psychoacoustic tonality calculation method

The reader is referred to ECMA-418 “Psychoacoustic metrics for ITT equipment - Part 2 (models based onhuman perception)”. ECMA-418-2 Clause 6 describes a perception-model-based procedure for determining
whether or not noise emissions contain prominent tonalities, and if present, their strengths: the psychoacoustic
tonality calculation method. Prominent perceived tonalities arise from a variety of causes including but notlimited to prominent discrete tones: discrete tones, non-pure tones, narrow elevated noise bands, combinationsof tones and narrow elevated noise bands, and combinations of these. Noise data recorded per ECMA-74 areused to implement the psychoacoustic methods of ECMA-418-2.

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Annex H(informative)
Identification and evaluation of prominent roughness using a
psychoacoustic roughness calculation method

The reader is referred to ECMA-418 “Psychoacoustic metrics for ITT equipment - Part 2 (models based onhuman perception)”. ECMA-418-2 Clause 7 describes a perception-model-based procedure for determining
whether or not noise emissions contain prominent roughness, and if present, their strengths: the psychoacoustic
roughness calculation method. Roughness originates for example from a multiplicative combination of two
vibrations – such as for example the gear mesh frequency and the rotational speed in a gear wheel – or fromsuperposition of two or more sounds with a similar frequency. In practice, roughness often occurs in rotating
components (engines, gearboxes, fans). Noise data recorded per ECMA-74 are used to implement thepsychoacoustic methods of ECMA-418-2.

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