ISO/TS 20646:2014

TECHNICAL ISO/TS
SPECIFICATION 20646
First edition
2014-02-01
Corrected version
2014-02-15
Ergonomics guidelines for the
optimization of musculoskeletal
workload
Lignes directrices ergonomiques pour l’amélioration des charges de
travail musculo-squelettiques
Reference number
©
ISO 2014
© ISO 2014
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ii © ISO 2014 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Terms and definitions . 1
3 General guiding principles . 2
3.1 Basic principles to improve MSWL . 2
3.2 Basic framework and responsibilities of MSWL-improvement activities . 2
3.3 Processes for MSWL risk assessment including implementation of risk reduction activity 3
Annex A (informative) Schedule form for principles, plan, and implementation .7
Annex B (informative) Checklist for hazard identification concerning musculoskeletal workload .8
Annex C (informative) Action-oriented checklist .12
Annex D (informative) Questionnaire for monitoring the effects of risk reduction measures
concerning musculoskeletal workloads .15
Annex E (informative) Evaluation form for the risk reduction measures .17
Bibliography .18
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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electrotechnical standardization.
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different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
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The committee responsible for this document is ISO/TC 159, Ergonomics, Subcommittee SC 3,
Anthropometry and biomechanics.
ISO/TS 20646 cancels and replaces ISO/TS 20646-1:2004, of which it constitutes a technical revision.
This corrected version of ISO/TS 20646:2014 incorporates the following corrections: the title has been
changed from Ergonomic procedures for the improvement of local muscular workloads to Ergonomics
guidelines for the optimization of musculoskeletal workload.
iv © ISO 2014 – All rights reserved

Introduction
The onset of work-related musculoskeletal disorders, such as low back pain and upper and lower limb
disorders, is becoming a great ergonomic concern in both industrialised and industrialising countries.
The high incidence of work-related musculoskeletal disorders is an important problem to be solved not
only to improve workers’ health and the quality of working life, but also to improve productivity.
In order to solve the problem of work-related musculoskeletal disorders, it is important to work out
primary preventive measures, through improving working conditions and providing adequate health
guidance and training, as well as to establish measures for secondary prevention, treatment, and
reassignment of the workers after a long sick leave.
Above all, the establishment of primary preventive measures, mainly measures to improve
musculoskeletal workloads (MSWL), are considered to be the most cost-effective solution and improve
the quality of working life. Various activities to improve MSWL have already been promoted. In addition,
regarding ISO/TC 159/SC 3, new standards are developed to improve working conditions relating to the
factors causing MSWL. However, in order to improve MSWL, it is indispensable to take a comprehensive
work-related perspective and find a solution, in consideration of the aforementioned factors.
TECHNICAL SPECIFICATION ISO/TS 20646:2014(E)
Ergonomics guidelines for the optimization of
musculoskeletal workload
1 Scope
This Technical Specification provides information and guidelines to properly utilize various ergonomics
standards concerning the factors related to musculoskeletal workload (MSWL), and helps develop
activities to reduce or optimize MSWL in workplaces and non-professional activities, in an effective
and efficient manner. The activities are intended to be based on a risk assessment. This Technical
Specification is intended primarily for employers, ergonomics and occupational health-related staff and
workers in enterprises, and workers. Prevention of MSWL is not always a matter of reducing the load.
The approach to reducing MSWL also involves assessing the work environment and organization as a
system to identify how changes can help to safely manage MSWL. Although this Technical Specification
provides ideas of effective and efficient measures to reduce or optimize MSWL, it does not certify the
complete prevention of health problems caused by MSWL.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
musculoskeletal workload
MSWL
loads on the musculoskeletal system required for working motions, maintaining working postures, and
exerting forces
2.2
harm
physical injury or damage to health
[SOURCE: ISO 12100]
2.3
hazard
potential source of harm
[SOURCE: ISO 12100]
2.4
risk
combination of the probability of occurrence of harm and the severity of that harm
[SOURCE: ISO 12100]
2.5
risk assessment
overall process comprising a risk analysis and risk evaluation
[SOURCE: ISO 12100]
2.6
risk analysis
combination of the specification of work description, hazard identification, and risk estimation
2.7
risk estimation
defining likely severity of harm and probability of its occurrence
[SOURCE: ISO 12100]
2.8
risk evaluation
judgment on the basis of successive risk analysis of whether the risk reduction objectives have been
achieved
[SOURCE: ISO 12100]
2.9
work space
volume of space allocated to one or more persons in the work system to complete a work task
[SOURCE: ISO 9241-5]
2.10
workstation
combination of work equipment for a particular person in a work space
Note 1 to entry: It is possible that several persons share a particular workstation, or that several persons alternate
between several workstations within any period of time (i.e. hourly, daily, weekly basis).
[SOURCE: ISO 11064-2]
3 General guiding principles
3.1 Basic principles to improve MSWL
Management should clarify in writing existing and predicted MSWL and possible health- and
productivity-related problems, and publish improvement goals and targets, a basic schedule to achieve
the targets, and the organization to implement the improvement (see Annex A).
3.2 Basic framework and responsibilities of MSWL-improvement activities
3.2.1 General
As organizations draft, implement, and assess MSWL-reduction plans, organizations at the enterprise
level and department level, and advisory organizations, should develop activities in a collaborative
manner. The participation of workers and/or their representatives is essential.
3.2.2 Enterprise level
A structure to manage MSWL should be established at the enterprise level, either as part of existing
management systems for work design or occupational safety and health, or as a specifically designated
project activity. The owner or executive director with overall management authority should be
responsible for the establishment and the conduct of this organization.
3.2.3 Department level
This refers to an organization within an individual department, for which the departmental manager
should be responsible. Its function is to draft, implement, and assess the improvement plans for the
department.
2 © ISO 2014 – All rights reserved

3.2.4 Advisory level
This refers to an organization offering advice concerning the validity of drafting, implementation, and
assessment of improvement plans. The organization can be established inside or outside the enterprise.
3.3 Processes for MSWL risk assessment including implementation of risk reduction
activity
3.3.1 General
An MSWL risk reduction plan should not be limited to a few specific factors causing loads. It should be
based on MSWL risk assessment in the workplace. On the basis of comprehensive risk assessment using
this multi-factorial analysis, specific action targets should be set to eliminate or reduce unacceptable
risks. Basic processes in achieving this target(s) are given in 3.3.1 to 3.3.4 (see ISO 12100).
3.3.2 Risk assessment
3.3.2.1 General
To study necessary activities to reduce the risks of MSWL, risk assessment should be implemented. This
includes a risk analysis with work description, hazard identification, and risk estimation as well as a
risk evaluation. Priority risks should be addressed immediately, so as to reduce risks or reinforce the
ongoing measures.
3.3.2.2 Specification of work situation
To study the characteristics of work, the following items should be described:
a) production process, contents of work, and tasks to be performed at the workplace;
b) statistics on occupational accidents, incidence of work-related diseases and other diseases, sick
leave, etc.;
c) work organization and shift systems;
d) work hours per day, week, month, or year;
e) operating time per day, continuous operating time, and a rest system;
f) characteristics of the workers, such as body size, muscle strength, history of injuries and diseases
affecting work, work experience, vocational education and training, and age;
g) characteristics of the work, such as static workload, physical inactivity, repetitive work, and manual
handling.
3.3.2.3 Hazard identification
The following factors are the main hazards for MSWL (see Annex B). They are divided into six sections.
3.3.2.3.1 Checklist section 1 — Work hours and work concentrations
a) long working shifts more than 8 h a day
b) frequent and long overtime work
c) long continuous operating time
d) insufficient rest breaks
e) insufficient days off
f) uneven work concentrations in a day, week, month, or year
g) uneven work concentrations between the workers
h) insufficient rest between shifts (less than 11 h)
3.3.2.3.2 Checklist section 2 — Type of work
a) lifting and carrying heavy objects (see ISO 11228-1)
b) work requiring great force
c) high pushing and pulling forces (see ISO 11228-2)
d) high repetitive work (see ISO 11228-3)
e) work requiring frequent finger, hand, or arm motions (see ISO 11228-3)
f) using hand-arm vibrating tools during the work
g) work using vehicles transmitting whole-body vibration
h) intensive work with a keyboard or other data entry devices
i) precision work
j) high visual requirements
3.3.2.3.3 Checklist section 3 — Postures and motions
a) awkward postures and motions (see ISO 11226)
b) continuous and/or highly frequent change in joint positions (see ISO 11228-3)
c)
...