ISO 11228-1:2021

INTERNATIONAL ISO
STANDARD 11228-1
Second edition
2021-10
Ergonomics — Manual handling —
Part 1:
Lifting, lowering and carrying
Ergonomie — Manutention manuelle —
Partie 1: Manutention verticale vers le haut, manutention verticale
vers le bas et manutention horizontale
Reference number
© ISO 2021
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Risk reduction for manual lifting or carrying tasks . 3
4.1 General . 3
4.2 Risk assessment (step model) . 3
4.2.1 Using the step model . 3
4.2.2 Recommended limit for manual lifting, lowering and carrying . 6
4.2.3 Cumulative mass of carrying . 9
4.3 Risk reduction . 10
4.4 Additional considerations . 10
Annex A (informative) Ergonomics approach to the design of lifting and carrying tasks .11
Annex B (informative) Reference mass determination .17
Annex C (informative) Assessment method for recommended limits for mass, frequency
and object position .19
Annex D (informative) Lifting index .27
Annex E (informative) Simplified model for RML and LI calculation .29
Annex F (informative) Multi-task manual lifting .31
Annex G (informative) Examples of manual handling of objects .42
Annex H (informative) Carrying.52
Annex I (informative) Exposure and risk: the basis for Table D.1 .55
Bibliography .61
iii
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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committee has been established has the right to be represented on that committee. International
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
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 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
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on the ISO list of patent declarations received (see www.iso.org/patents).
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expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 3,
Anthropometry and biomechanics.
This second edition cancels and replaces the first edition (ISO 11228-1:2003), which has been
technically revised.
The main changes to the previous edition are as follows:
— revision of the scope to include lowering;
— expansion of the risk estimation;
— expansion of Annexes A, B and C;
— addition of Annexes D to I to include updated information; expansions of the RNLE (revised NIOSH
lifting equation); more examples for lifting and carrying; detailed information on the scientific
background and recommended interpretation of the RNLE.
A list of all parts in the ISO 11228 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
0.1  General
The ISO 11228 series establishes ergonomic recommendations for different dynamic manual handling
tasks. It provides information for designers, employers, employees and others involved in work, job and
product design. The ISO 11228 series provides information on the evaluation of static postures.
Disorders of the musculoskeletal system are common worldwide and one of the most frequent
disorders in occupational health. The risk-assessment model in this document allows the estimation
of the risk associated with a manual material handling task. It takes into consideration the hazards
(unfavourable conditions) related to manual handling tasks and the time spent performing them.
Unfavourable conditions can include factors such as the size and mass of the object being handled,
working posture (e.g. twisting, bending, overreaching), quality of grip on items, and the frequency and
duration of manual handling. Any of these can, alone or in combination, lead to a hazardous handling
activity and increase the risk of musculoskeletal disorders. Accordingly, these factors are considered
when determining a recommended safe limit of the mass of objects being handled.
The method of determination of safe recommended limits in this document is based on the integration
of data derived from four major research approaches, namely the epidemiological, the biomechanical,
the physiological and the psychophysical approach.
0.2  The ergonomic approach
0.2.1  General
Ergonomics pursues the specific goals of optimizing human well-being and overall system performance.
This is achieved through contributions to the design and evaluation of tasks, jobs, production,
environment and systems in order to make them compatible with the needs, abilities and limitations
of people. It strives to design or to modify a work system to accommodate, as far as possible, a broad
range of people in order to meet the needs of workers with various characteristics, including people
with special requirements. Thus, the development of special solutions for individuals can be minimized.
Achieving these goals also contributes to organizational sustainability and social responsibility.
Manual handling tasks in the workplace occur within the context of work systems. Interactions of
humans with items, information, environment and other people must be taken into consideration when
designing or modifying tasks and work areas. The ergonomics approach can be used to prevent manual-
handling-related injuries from occurring by being used proactively in the design of processes, systems
or work organization, in addition to when modifications to existing systems are being considered.
The ergonomic approach considers tasks in their entirety, taking into account a range of relevant
factors including the nature of the task, the characteristics of objects handled, the working environment
and the individuals performing the task. It considers environmental conditions (e.g. lighting, noise,
temperature), as well as an individual’s characteristics and experiences. An individual’s characteristics
include physical and mental capabilities, skills, work techniques, behaviour and their perception of the
work environment and its social characteristics.
0.2.2  Organizational considerations
Work organization (e.g. task duration, job duration, recovery time, shift patterns) is a contributing
factor in the prevention or development of musculoskeletal disorders. For example, recovery periods
help to mitigate possible muscular fatigue and help to avoid the overuse of similar muscle groups over
the duration of the work shift. Job rotation, job diversification and job enlargement are all methods of
structuring the work to facilitate variation and recovery within the work period.
Work organization includes appropriate training of workers, including how to safely perform tasks,
how to recognize and respond to hazardous conditions in workplaces, and which procedures and
communication channels to use to report and correct hazards. Regularly and properly maintained
equipment and facilities contribute to safer work, including manual handling tasks. The selection of
v
equipment and supplies which are appropriate for the workplace and task conditions helps to make
work demands safer.
0.2.3  Psychological health and safety and the ergonomics approach
The ergonomics approach considers the cognitive or psychological demands on humans, as well
as the psychosocial environment in which work takes place. Psychological response to work and
workplace conditions (psychosocial factors) has an important influence on mental, physiological and
musculoskeletal health. Psychosocial factors in the workplace include the design, organization and
management of work, work content, job complexity, job demands (cognitive and physical), job content
and the overall social environment (i.e. the context of work).
Undesirable psychosocial aspects of a job can include:
— little or no control over work methods or organization;
— high levels of attention and concentration required;
— poor use of skills;
— little or no involvement in decision-making;
— repetitive, monotonous tasks only;
— machine- or system-paced work;
— work demands perceived as excessive;
— payment systems which encourage working too quickly or without breaks;
— work systems that limit opportunities for social interaction;
— high levels of effort not balanced by sufficient reward (e.g. resources, remuneration, self-esteem,
status);
— no training and skill enhancement encouraged or supported;
— poor co-worker or supervisory support.
Many of the effects of these factors on workers occur via stress-related processes, which can in turn
have a direct effect on biochemical and physiological responses, which can increase the likelihood of
experiencing musculoskeletal injury. Thus, for the prevention of musculoskeletal disorders (MSDs),
these psychosocial stressors should be controlled in addition to the biomechanical risk factors. For
more information on the effects of the psychosocial stressors on MSDs, see References [63] to [66]. For
further information on psychological health and safety in the workplace, see References [1] to [42]
vi
INTERNATIONAL STANDARD ISO 11228-1:2021(E)
Ergonomics — Manual handling —
Part 1:
Lifting, lowering and carrying
1 Scope
This document specifies recommended limits for manual lifting, lowering and carrying while taking into
account the intensity, the frequency and the duration of the task. It is designed to provide requirements
and recommendations on the assessment of several task variables, allowing the health risks for the
working population to be evaluated.
This document applies to manual handling of objects with a mass of 3 kg or more and to moderate
walking speed, i.e. 0,5 m/s to 1,0 m/s on a horizontal level surface.
This document is based on an 8 h working day, but also covers more prolonged working times, up to
12 h. It also addresses the analysis of combined lifting, lowering and carrying tasks in a shift during a
day.
This document does not cover the holding of objects (without walking), the pushing or pulling of objects
or manual handling while seated. The pushing and pulling of objects are covered in the other parts of
the ISO 11228 series.
This document does not cover handling people or animals. (For further information on handling people,
refer to ISO/TR 12296.)
This document does not address the manual lifting of objects while using lift-assistive devices such as
exoskeletons and does not address the needs of pregnant women or persons with disabilities.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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
manual handling
activity requiring the use of human force to lift, lower, carry or otherwise move or restrain an object
3.2
lifting
manually (i.e. without using mechanical assistance) moving an object from its initial position
3.3
lowering
manually (i.e. without using mechanical assistance) moving an object from its initial position
downwards
Note 1 to entry: Included in lifting.
3.4
carrying
manually (i.e. without using mechanical assistance) moving an object which is held with either one or
two hands, or positioned on one or two shoulders or on the neck, by walking one metre or more
Note 1 to entry: Does not include the use of backpacks.
3.5
risk assessment
overall process comprising a risk analysis and risk evaluation
3.6
reference conditions
set of conditions (environmental, physical, biomechanical and task-design-related) which are
considered to be the ideal conditions for safe manual handling to take place
Note 1 to entry: See 4.2.1, 4.2.3.2, A.4 and H.1 for detailed definitions of lifting and carrying conditions.
3.7
repetitive lifting
lifting an object more than once every 10 min
Note 1 to entry: Infrequent lifting at one lift every 10 min is defined in Reference [57], where a multiplier of 1,0 is
applied for all duration scenarios at a frequency of 1 lift per 10 min.
3.8
mid-sagittal plane
vertical plane in the anterior-posterior direction that divides a person assuming a neutral body posture
into equal left and right halves
Note 1 to entry: See Figure C.1
Note 2 to entry: A neutral body posture is an upright standing posture with the arms hanging freely by the side
of the body.
3.9
plane of asymmetry
vertical plane passing through the midpoint of the line between the inner ankle bones and the centre
of gravity of the load when the load is at its most extreme displacement from the neutral, mid-sagittal
plane
3.10
angle of asymmetry
angle formed between the lines that result from the intersections of the mid-sagittal plane and the
plane of asymmetry
Note 1 to entry: If the feet are repositioned during the lift or lower sequence, the referent planes shall be
determined at the point in the action sequence where the largest degree of asymmetrical twist is encountered
(see Figure C.1).
3.11
reference mass
mass considered appropriate for use with an identified user population during the application of the
risk-assessment method described herein
3.12
cumulative carried mass
product of the carried mass and the carrying frequency
Note 1 to entry: The cumulative mass for carrying is defined in kilograms per minute to represent the risk for
short-term carrying, in kilograms per hour to represent the risk for medium-term carrying and in kilograms per
8 h to represent the risk for long-term carrying.
3.13
recovery time
time used for determining the work/recovery pattern, which is the period of light work activity Note 1
to entry: Light work activity can include monitoring activities, light assembly work using the upper
limbs, work not involving lifting or lowering or carrying > 3 kg, and work not involving pushing or
pulling.
4 Risk reduction for manual lifting or carrying tasks
4.1 General
Risk assessment is the overall process of risk identification, risk analysis and risk evaluation, the results
of which are ultimately used in the effort to reduce risk. The goal in manual materials handling risk
reduction is to take measures to improve the design of the task, the object and the working environment
relative to the characteristics of the individuals performing the work.
In those cases where manual handling cannot be avoided, a risk assessment shall be completed to
determine if, and to what extent, modifications are recommended. The risk assessment takes into
account the mass of the object, the grip on the object, the position of the object relative to the position of
the body, and the frequency and duration of a specific task.
The risk assessment is accomplished using the step-by-step approach illustrated in Figure 1 (step
model). With each successive step, the evaluator analyses the interrelated aspects of the tasks.
If recommended limits are exceeded, the task shall be adapted in such a way that all questions in the
step-by-step approach are satisfied.
Employees engaged in manual handling should be provided with adequate information and training on
how to perform these tasks safely. The provision of this information and training does not, in isolation,
ensure safe manual handling in all cases. However, it is an integral part of the ergonomics approach,
and the risk of injury can be reduced by adopting safe ways of manual handling (see A.6).
4.2 Risk assessment (step model)
4.2.1 Using the step model
The step model illustrated in Figure 1 describes the steps involved in beginning, and working through,
a risk assessment of manual handling tasks, including lifting and carrying. Initially, the mass of the
object being handled is determined; if it is more than 3 kg, the risk assessment is continued. The task is
further analysed to determine if the mass exceeds recommended limits for handling (step 1).
The user shall make modifications where limits are exceeded. In those tasks where lifting and carrying
is repetitive, the assessment is continued using the quick assessment procedure (step 2). Based on the
outcome of step 2, the task will possibly:
— require immediate modifications for safety (see Annex A for further information);
— be determined to be acceptable; or
— need further, more detailed, risk evaluation (step 3).
Step 3 is also used for evaluating tasks which take place using non-ideal postures.
The reference condition of manual lifting and lowering posture for manual handling is:
— an upright symmetrical trunk posture (no twisting or lateral bending);
— sagittal trunk inclination of no more than 15° (the minimum inclination observable with the human
eye) from the vertical to accommodate the natural posture of the back;
— the horizontal distance between the object being handled and the centre of mass of the worker as
close as possible;
— the grip height lying within knuckle and elbow height for lifting or between knuckle and shoulder
height for carrying (for anthropometric measurements see ISO 7250-3).
Steps 4 and 5 assist with the further evaluation of the task for cumulative mass for lifting and carrying.
Key
m mass of object to be lifted
M reference mass for identified user population group
ref
M cumulative mass (carried)
cum
d duration (of carrying)
c
LI lifting index
Figure 1 — Step model
4.2.2 Recommended limit for manual lifting, lowering and carrying
4.2.2.1 Weight of the object
Whenever an object of 3 kg or more is lifted or carried, a risk assessment shall be performed, beginning
with the initial screening, step 1. Note that throughout the text whenever the term “lifting” is used the
act of “lowering” is implied.
4.2.2.2 (Step 1) Initial screening
An initial screening of non-repetitive lifting and carrying (performed with reference conditions in
place) requires the determination of the object's mass (step 1). The recommended limit for the mass of
the object, referred to as the reference mass, m , and based on population characteristics, is presented
ref
in Annex B. For general guidance for designers and additional information related to step 1, see Annex A.
4.2.2.3 (Step 2) Quick assessment of repetitive lifting and carrying
Screening of repetitive lifting and carrying tasks of objects of 3 kg or more is performed using the quick
assessment procedure.
The quick assessment procedure aims to identify, without the need for calculation, the presence of two
opposite exposure conditions:
— acceptable condition, where unacceptable risk has not been identified;
— critical condition, where unacceptable risk has been identified.
When either of these conditions is met, it is not necessary to perform a more detailed evaluation of
the exposure level. Instead, either no further modifications need to be considered (acceptable risk, see
Table 1 and Table 2) or modifications should be made immediately (see Annex A for guidance) due to the
presence of a critical condition (see Table 3). In either case, Table 4 shall also be referenced to identify
the presence of any unfavourable working environment or object circumstances which can further
increase the risk of the task (additional factors).
When neither of the two extreme conditions is met, it is necessary to conduct further risk evaluation by
methods presented in step 3 (see 4.2.2.4).
Table 1 and Table 2 are used for establishing the acceptable risk condition. If all of the listed conditions
are present (yes for each condition), the examined task is acceptable and it is not necessary to continue
with a risk evaluation. If any answers are no, then Table 3 shall be used to confirm if there are critical
conditions. If any of these conditions is met (a yes response), the task shall not be performed before
modifications are made.
In either case, Table 4 shall also be systematically used to identify the presence of any unfavourable
working environment or object characteristics which will potentially further increase the risk of the
task. These factors can be related to the work environment or to the object characteristics, and they
shall be addressed to help reduce risk.
Table 1 — Lifting and lowering — Quick assessment — Acceptable condition
Lifting and lowering
Asymmetry (e.g. body rotation, trunk twisting) is absent No Yes
Load is maintained close to the body (e.g. where space between the body and No Yes
the item is minimized)
3 kg to 5 kg
Load vertical displacement is between hips and shoulders No Yes
Maximum frequency: less than five lifts per minute No Yes
Table 1 (continued)
Asymmetry (e.g. body rotation, trunk twisting) is absent No Yes
Load is maintained close to the body (e.g. where space between the body and No Yes
the item is minimized)
> 5 kg to 10 kg
Load vertical displacement is between hips and shoulder No Yes
Maximum frequency: less than one lift per minute No Yes
More than 10 kg Loads of more than 10 kg are absent No Yes
If all of the questions are answered yes, then the examined lifting task is acceptable and it is not necessary to
continue the risk evaluation, except to review Table 4 for other factors to be considered.
If at least one of the questions is answered no, the evaluation shall continue (see Table 3 and Table 4).
Table 2 — Carrying — Quick assessment — Acceptable condition
Carrying
Calculate the cumulative mass (total kg carried during the given durations for the given distance below).
Is the carried cumulative mass less than or equal to recommended cumulative masses values considering distances
(±5 m) and duration (1 min; 1 h; 4 h; 8 h)?
Distance 1 m to ≤ 5 m per
Duration Distance > 5 m to 10 m per action
action
6 h to 8 h 4 800 kg 3 600 kg No Yes
4 h 4 000 kg 3 000 kg No Yes
1 h 2 000 kg 1 500 kg No Yes
1 min 60 kg 45 kg No Yes
Acceptable conditions for carrying: carry with two hands over a maximum
distance of 10 m, picking up and setting down the object at height, where the
pick-up and set-down height ranges between 0,75 m and 1,10 m, with the full
cycle including returning back to the start point empty-handed over the same
No Yes
distance. The carrying exercise is performed in a comfortable indoor envi-
ronment, on a hard, flat, non-slip floor, without any obstacles in the way, and
in a workspace allowing free body movement and posture. No constraints are
placed on the subject. Awkward postures during the carrying are not present.
If all of the questions are answered yes, then the examined carrying task is acceptable and it is not necessary to
continue the risk evaluation except to review Table 4 for other factors to be considered.
If at least one of the questions is answered no, the evaluation shall continue (see Table 3 and Table 4).
Table 3 — Lifting or carrying— Quick Assessment — Critical condition
Critical condition for lifting: task layout and frequency conditions exceeding the maximum suggested
The hand location at the beginning and end of the lift is
Vertical location No Yes
higher than 175 cm or lower than the surface at the feet
The vertical distance between the origin and the destination
Vertical displacement No Yes
of the lifted object is more than 175 cm
The horizontal distance between the body and load is greater
Horizontal distance No Yes
than full arm reach (>63 cm)
Extreme body twisting (to either side by more than 45°)
Asymmetry No Yes
without moving the feet
Table 3 (continued)
[56]
Frequency of lifts More than 15 lifts per min of short duration (manual han-
dling lasting no more than 60 min consecutively in the shift, No Yes
followed by at least 60 min of recovery time)
More than 12 lifts per minute of medium duration (manual
handling lasting no more than 120 min consecutively in the No Yes
shift, followed by at least 30 min of recovery time
More than 10 lifts per minute of long duration (manual han-
No Yes
dling lasting more than 120 min consecutively in the shift)
Critical condition for lifting or carrying: presence of loads exceeding the following limits (see Table B.2
for further information)
Females (20 to 45 years) 20 kg No Yes
Females (<20 or > 45 years) 15 kg No Yes
Males (20 to 45 years) 25 kg No Yes
Males (<20 or > 45 years) 20 kg No Yes
Critical condition for carrying: presence of cumulative carried mass greater than those indicated also
with acceptable conditions for carrying
Carrying distance (per
action) 1 m to 5 m over a 6 000 kg in 6 h to 8 h No Yes
6 h to 8 h period?
Carrying distance (per
action) 5 m to 10 m over a 3 600 kg in 6 h to 8 h No Yes
6 h to 8 h period?
Carrying distance (per
action) 10 m to 20 m over 1 200 kg in 6 h to 8 h No Yes
a 6 h to 8 h period?
Carrying distance (per
Carrying distance is usually more than 20 m No Yes
action) more than 20 m
If at least one of the conditions has a yes response, then consider risk as high and a critical condition is present.
Proceed with task redesign and continue to Table 4 to identify additional factors to be considered, and then con-
tinue to Annex A for identifying urgent corrective actions.
Table 4 — Lifting and carrying — Additional factors to be considered
Is the working environment unfavourable for lifting and carrying?
Presence of extreme (low or high) thermal stress (e.g. temperature, humidity, air movement) No Yes
Presence of slippery, uneven, unstable floor No Yes
Presence of insufficient space for lifting and carrying No Yes
Are there unfavourable object characteristics for lifting and carrying?
The size of the object reduces the worker’s view and hinders movement No Yes
The load centre of gravity is not stable (e.g. liquids, items moving around inside of object) No Yes
The object shape or configuration presents sharp edges, surfaces or protrusions No Yes
The contact surfaces are too cold or too hot No Yes
Improper handholds or coupling
Does the lifting or carrying task(s) last more than 8 h a day? No Yes
If at least one of the questions is answered yes, the specified condition shall be addressed and the risks minimized.
4.2.2.4 (Step 3) Recommended limits for mass, frequency and object position
When none of the two conditions identified in step 2 is met, it is necessary to conduct a risk evaluation
(step 3) to determine the recommended limits for the task.
To determine the recommended mass limit (RML; Annex C) while taking into account working posture,
object position and lifting frequency and duration, use Formulae (C.1) to (C.5). These formulae take
into account task variables (characteristics of the task). A lifting index (LI; Annex D) is also calculated
for further risk exposure information. The analyst first checks if the RML for lifting is exceeded and,
if so, checks if the LI exceeds appropriate limits (Table D.1). If both are exceeded then the task shall
be adapted by changing the mass, the lifting frequency, the lifting duration or the object position.
Table D.1 provides interpretation of the results and consequent measures. Annex E reports a simplified
model for RML and LI calculation. Annex F reports procedures for analysing multiple manual lifting
tasks (composite, variable and sequential lifting tasks), Annex G reports examples of analysis of simple
and variable lifting tasks. Annex I reports a brief review of the relevant literature regarding the
interpretation of the lifting index and is the basis for Table D.1.
4.2.3 Cumulative mass of carrying
4.2.3.1 General
For an object to be carried once for a modest distance (one or two steps or less than 1 m), only the limits
for lifting shall be applied as per steps 1, 2 and 3.
For screening the cumulative mass per day for carrying (step 4), the recommended limits in 4.2.2.2
and 4.2.2.3 shall initially be used. Once this has been completed, limits recommended in 4.2.3.2 for a
reference carrying condition shall be applied.
For determining the cumulative mass of carrying related to distance, time patterns and other
influencing factors, refer to 4.2.3.3 (step 5).
4.2.3.2 (Step 4) Recommended limit for cumulative mass per day
The cumulative mass in a certain period is calculated as a product of mass and frequency of carrying.
These two values are limited in steps 1, 2 and 3. In this way, the reference mass cannot exceed a
maximum of 25 kg (i.e. mass shall decrease from 25 kg as the frequency increases) and the frequency of
carrying should never exceed a maximum of 15 times per minute (i.e. frequency shall decrease from 15
times per minute when the mass being carried is increased).
Reference conditions are described as carrying an object with two hands over a distance of 2 m, picking
up and setting down the object at height, where the pick-up and set-down height ranges between 0,75 m
and 1,10 m, with the full cycle including returning back to the start point empty-handed over the same
distance. The carrying exercise is performed in a comfortable indoor environment, on a hard, flat,
non-slip floor, without any obstacles in the way, and in a workspace allowing free body movement and
posture. No constraints are placed on the subject.
Reference conditions regarding distance, way back and environmental and workspace conditions shall
be adopted for carrying on shoulder(s) or neck. The height of picking up and object release is about
shoulder height (125 cm to 155 cm). Alternatively, these actions are performed by a co-worker, for
example a co-worker placing a load on the shoulder of another worker who then carries it.
With reference conditions in place, the recommended limit for cumulative mass of carrying is 6 000 kg
per 8 h.
4.2.3.3 (Step 5) Recommended limit for cumulative mass of carrying related to time patterns,
distance and other influencing factors
For carrying with reference conditions in place, the recommended limits for cumulative mass
[11],[28],[36],[38]
considering the different duration scenarios for carrying are presented in Table 5 .
Table 5 — Recommended limits in the carrying reference conditions for cumulative mass
related to carrying duration during the shift (for general working population)
Carrying dis- kg per min kg per 1 h kg per 2 h kg per 3 h kg per 4 h kg per 5 h kg per 6 h
tance > 1 m and ≤ 2 m to 8 h
Recommended limits
for cumulative mass 75 2 500 3 400 4 200 5 000 5 600 6 000
for manual carrying
To evaluate the cumulative mass carried, the duration of the carrying tasks in a period of time shall
be considered. Table 5 provides recommended limit values of cumulative mass based on time devoted
to manual handling (including loads that are both lifted and then carried) in the shift and represents
the product of handling different possible masses at different frequencies. For example, the limit of a
cumulative mass of 75 kg for a single minute can be achieved by a mass of 12,5 kg × 6 times/min.
When carrying conditions differ from the reference condition, recommended limits in Table 5 shall
be adjusted by applying correction ratios (multipliers) into the calculation. The multipliers represent
true conditions of the task as observed (e.g. carrying distance, height of pick up or set down and other
relevant conditions). Multipliers are provided in Annex H.
4.3 Risk reduction
Risk reduction can be achieved by minimizing or excluding hazards resulting from the task, the object,
the workplace, the work organization or the environmental conditions; examples are given in A.3 to
A.5.
4.4 Additional considerations
Health surveillance should be provided by the employer with respect to work-related risks.
Health surveillance is preventive in nature and should ensure, before starting the job and then on
an ongoing basis, that the relationship between the individual’s health status and his or her working
conditions is satisfactory.
More specifically, health surveillance aims to:
— identify any negative health conditions at an early enough stage to prevent them from worsening;
— identify people who require greater protective measures in addition to those adopted for other
workers;
— contribute, based on appropriate feedback, towards enhancing the accuracy of collective and
individual risk assessments;
— monitor preventive measures to ensure their continuing adequacy;
— collect exposure or injury data in order to compare different groups of workers and different
scenarios;
— collect data on absences caused by specific disorders so as to estimate the cost of non-prevention.
Health surveillance related to manual handling should be focused both on the spine and on other
parts of the body, especially considering the involvement of the shoulders and the upper limbs.
Personal mental health (e.g. depression) and work-related psychosocial factors (e.g. job satisfaction,
supervisory support) should also be considered in health surveillance for comprehensive prevention of
musculoskeletal injuries or disorders in the workplace.
Technical or mechanical means of reducing risk should be provided and complemented with information
and appropriate training on how to use manual materials handling aids appropriately (see A.6). All
workers should be provided with information regarding work-related hazards, their risks and how to
safely minimize exposure.
Annex A
(informative)
Ergonomics approach to the design of lifting and carrying tasks
A.1 General
Scientific knowledge stresses the importance of an ergonomic approach in removing or reducing the risk
of manual-handling-related injury. Ergonomics focuses on the design of work and its accommodation of
human needs and physical and mental capabilities.
In seeking to avoid injury from manual handling, it is pertinent to ask whether manual handling which
is hazardous or presents a risk of injury can be eliminated altogether. Those designing new systems of
work, or installing new plants, should consider introducing an integrated handling system that, where
appropriate, fully utilizes powered or mechanical handling rather than a manual system. It should,
however, be remembered that the introduction of automation or mechanization can create different
risks. Mechanization, for example, by the introduction of a lift truck, hoist, trolley, sack truck, chute
or pallet inverter, needs to be well maintained and a defect-reporting and -correction system should
be implemented. All handling aids should be compatible with the rest of the work system, effective,
appropriately designed and easily operated. Training concerning handling aids should cover their
appropriate usage, and knowledge of safe storage and procedures to be used in the event of breakdown.
Training should also include techniques on appropriate body positioning when using the equipment.
Operating instructions and safety concerns should be clearly placed on the equipment.
If manual handling cannot be avoided, technical aids should be available. Handling devices such as
hand-held straps, slide mats, hooks or suction pads can simplify the problem of handling an object.
A.2 Design of the work: task, workplace and work organization
A.2.1 Task
Stress levels on the back increase substantially as the distance between the object and the body
increases. Therefore, in the planning of tasks it is relevant to avoid long reaching, twisting, stooping,
bending and awkward movements or postures. Being able to gain secure and close footing to the object
is central to designing for good posture. Often obstacles that prevent this can be avoided; a common
example is long reaches across to an object from the far side of a pallet, which can be resolved by the
use of pallet-rotating equipment. Another example where awkward postures are seen and alternatives
are achievable is retrieving objects from the rear of deep shelves or racks less stressfully by installing
rollers. The best height for storage is between the mid-thigh and chest height of the workers involved,
with lighter items being stored above or below this region.
A good grip is essential for avoiding accidents with respect to handling and is often determined by the
characteristics of the object. This means that the object should normally be equipped with suitable
handles, cut-outs or finger slots. Objects with large dimensions should have two handles. The handles
should be of sufficient dimensions and should be placed so that the centre of gravity falls at the midpoint
of the line between the two handles.
A.2.2 Workplace
The work area should be designed to minimize the amount of manual effort, thus reducing the need
for twisting, bending, reaching and carrying. The distance that both typical and infrequently handled
objects have to be moved should be taken into account, together with the heights between which objects
can be transferred.
Gangways and other working areas should be large enough to allow adequate room to manoeuvre.
Sufficient space is a prerequisite for efficiently carrying out work in appropriate working postures.
Also, the use of suitable mechanical devices often requires more room than manual lifting.
A person carrying an object should have a clear view ahead, unobstructed by the object. Lifting and
carrying on stairways and on ladders should be avoided.
It is important to provide adequate space around the object and in the gangways, as well as sufficient
headroom to avoid stooping postures while handling an object.
Floor or ground surfaces should be level, well maintained, not slippery and clear of obstacles to avoid
potential slipping or tripping accidents. The presence of steps, steep slopes and ladders can increase
the risk of injury by adding to the complexity of movement when handling objects. Debris and materials
(e.g. used wrapping materials) can also pose tripping and slipping h
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