ISO 20321:2020

INTERNATIONAL ISO
STANDARD 20321
First edition
2020-03
Petroleum, petrochemical and natural
gas industries — Safety of machineries
— Powered elevators
Industries du pétrole, de la pétrochimie et du gaz naturel — Sécurité
des machines — Élévateurs motorisés
Reference number
ISO 20321:2020(E)
©
ISO 2020

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ISO 20321:2020(E)

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© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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ISO 20321:2020(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Abbreviated terms . 5
5 Safety requirements and/or protective/risk reduction measures . 5
5.1 General requirements for powered elevators . 5
5.2 Mechanical strength . 5
5.3 Safety design of powered elevators . 5
5.3.1 General. 5
5.3.2 Ergonomic design . 5
5.3.3 Fastening methods and DROPS prevention of parts . 5
5.3.4 Suspension points . 6
5.3.5 Moving parts, pinch points and guards . 6
5.4 Other protective measures . 7
5.4.1 Risks due to surfaces, edges or angles . 7
5.4.2 Size and type verification (errors of fitting) . 7
5.4.3 Static electricity . 7
5.4.4 Loss of stability . 7
5.4.5 Explosion prevention . 7
5.4.6 Controls . 7
5.4.7 Elevator coating . 7
5.4.8 Noise . 8
5.5 Specific risks for powered elevators . 8
5.5.1 General. 8
5.5.2 External power source . 8
5.5.3 Feedback signals . 8
5.5.4 Danger zone . 8
5.6 Stops for an assembly of machinery . 9
5.6.1 General. 9
5.6.2 Start of the movement . 9
5.6.3 Normal stop . 9
5.6.4 Operational stop . 9
5.6.5 Emergency shutdown . 9
5.7 Failure of power supply .10
5.8 Verification of safety requirements and/or protective/risk reduction measures .10
5.8.1 General.10
5.8.2 Service life .10
5.8.3 Fatigue life .10
5.8.4 Maintenance .10
6 Functions for preparing the elevator for a safe lift — Wrapping, securing, locking
and verification .10
6.1 General .10
6.2 Black box approach .11
6.3 Wrapping.11
6.4 Securing.12
6.5 Locking .13
6.6 Verification of readiness for safe lift .13
7 Closed-ring powered elevator .14
7.1 Wrapping.14
7.2 Securing and locking .14
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ISO 20321:2020(E)

7.3 Verification .14
8 Instructions for use .14
8.1 General .14
8.2 Instruction handbook .14
9 Marking of powered elevators.17
Annex A (informative) Relation between the clauses of European Directive on machinery
(Directive 2006/42/EC) and this document .19
Annex B (normative) Verification tests for powered elevators .23
Bibliography .25
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ISO 20321:2020(E)

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
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
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
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
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 67, Materials, equipment and offshore
structures for petroleum, petrochemical and natural gas industries, Subcommittee SC 4, Drilling
and production equipment, in collaboration with the European Committee for Standardization
(CEN) Technical Committee CEN/TC 12, Materials, equipment and offshore structures for petroleum,
petrochemical and natural gas industries, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
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.
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ISO 20321:2020(E)

Introduction
This document is a type-C standard as stated in ISO 12100.
This document is of relevance, in particular, for the following stakeholder groups representing the
market players with regard to machinery safety:
— machine manufacturers (small, medium and large enterprises);
— health and safety bodies (regulators, accident prevention organizations, market surveillance, etc.)
Others can be affected by the level of machinery safety achieved with the means of the document by the
above-mentioned stakeholder groups:
— machine users/employers (small, medium and large enterprises);
— machine users/employees (e.g. trade unions, organizations for people with special needs);
— service providers, e. g. for maintenance (small, medium and large enterprises);
— consumers (in case of machinery intended for use by consumers).
The above-mentioned stakeholder groups have been given the possibility to participate at the drafting
process of this document.
The machinery concerned and the extent to which hazards, hazardous situations or hazardous events
are covered are indicated in the Scope of this document.
When requirements of this type-C standard are different from those which are stated in type-A or
type-B standards, the requirements of this type-C standard take precedence over the requirements of
the other standards for machines that have been designed and built according to the requirements of
this type-C standard.
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INTERNATIONAL STANDARD ISO 20321:2020(E)
Petroleum, petrochemical and natural gas industries —
Safety of machineries — Powered elevators
1 Scope
This document specifies general safety requirements for the design, testing and production of powered
elevators. The requirements are applicable for onshore and offshore applications of such elevators in
the petroleum and petrochemical industries.
This document does not cover any other type of elevator. It is not applicable to the following types of
products:
— remote control devices;
— lifting nubbins;
— lifting plugs;
— lifting subs;
— internal gripping devices;
— equipment for lifting tubular from and onto a vessel;
— elevator links or bails.
This list is not exhaustive.
This document is not applicable to powered elevators manufactured before the date of this publication.
NOTE Annex A provides the relation between the clauses of the European Directive on machinery (Directive
2006/42/EC) and this document, for potential significant hazards and the safety requirements dealing with
them for powered elevators.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3864 (all parts), Graphical symbols — Safety colours and safety signs
ISO 12100, Safety of machinery — General principles for design — Risk assessment and risk reduction
ISO 13849-1, Safety of machinery — Safety-related parts of control systems — Part 1: General principles
for design
ISO 13534, Petroleum and natural gas industries — Drilling and production equipment — Inspection,
maintenance, repair and remanufacture of hoisting equipment
ISO 13535:2000, Petroleum and natural gas industries — Drilling and production equipment — Hoisting
equipment
ISO 13850, Safety of machinery — Emergency stop function — Principles for design
ISO 13854, Safety of machinery — Minimum gaps to avoid crushing of parts of the human body
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ISO 20321:2020(E)

ISO 14120, Safety of machinery — Guards — General requirements for the design and construction of fixed
and movable guards
ISO 80079-36, Explosive atmospheres — Part 36: Non-electrical equipment for explosive atmospheres —
Basic method and requirements
ISO 80079-37, Explosive atmospheres — Part 37: Non-electrical equipment for explosive atmospheres — Non-
electrical type of protection constructional safety “c”, control of ignition sources “b”, liquid immersion “k”
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
control system
system that responds to input signals from parts of the elevator (3.5), operators, external control
equipment or any combination of these, and generates corresponding output signals to the elevator
actuators, causing the elevator to perform in the intended manner
3.2
danger zone
space within, under and/or around machinery in which a person can be exposed to a hazard
[SOURCE: ISO 12100:2010, 3.11]
3.3
design verification
process of examining the result of a given design or development activity to determine conformity with
specified requirements
[SOURCE: ISO/TS 29001:2010, 3.1.8]
3.4
DROPS
dropped objects
industry-wide initiative focused on preventing dropped objects
Note 1 to entry: DROPS ultimate goal is delivering a second nature dropped objects prevention strategy across
the industry.
3.5
elevator
lifting accessory to be used for lifting and handling of tubular in the on- and offshore drilling industry
on or in the vicinity of the drill floor
3.6
fatigue life
number of stress cycles of a specific character that an elevator (3.5) sustains before failure of a specified
nature occurs
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ISO 20321:2020(E)

3.7
feedback signal
signal generated by the elevator (3.5) that can be used for monitoring or functional use
Note 1 to entry: Examples of feedback signals include elevator set for safe lifting, weight in elevator, and
elevator open.
3.8
insert
gripping/holding device, with or without teeth that embed into the side of the tubular, which can create
friction in order to suspend the tubular
3.9
interface
connection of the elevator (3.5) with the associated external infrastructure and vice versa
Note 1 to entry: The interface can be any transfer of signals or power by means of for example hydraulics,
pneumatics, electrics or wireless.
3.10
internal control device
device located on the elevator (3.5) itself
Note 1 to entry: Internal control devices are parts of the control system (3.1), which detect input signals and/or
generate output signals.
3.11
locking
ensuring that the securing is maintained
3.12
movement of the powered elevator
movement of parts of the elevator (3.5), excluding movements of the elevator (e.g. generated by the
top drive)
3.13
pick up
lifting tubular from a non-vertical (typical near horizontal) position outside the drill floor area into a
vertical position in the drill floor area
3.14
powered elevator
lifting accessories to be used for lifting and handling of tubular in the onshore and offshore drilling
industry on or in the vicinity of the drill floor, of which the movement of the mechanics is done partly or
completely mechanically using a power source (3.15)
3.15
power source
engine or motor which provides mechanical energy for linear or rotational movement
[SOURCE: ISO 11449:1994, 3.2]
3.16
primary feedback signal
signal generated by the elevator status that indicates the elevator (3.5) is set for safe lifting
3.17
product verification
evaluation of the implementation of the product against the requirements to determine that they have
been met
[SOURCE: ISO 16404:2013, 3.3]
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ISO 20321:2020(E)

3.18
remote control device
device located at a distance from the elevator (3.5)
Note 1 to entry: Remote control devices are parts, which detect input signals and/or generate output signals.
3.19
safe lift
lifting of tubular in a safe way, without creating an unacceptable risk for equipment and personnel
Note 1 to entry: Safe lifts are ensured by maintaining sufficient contact between the elevator (3.5) and the
tubular to be lifted, preventing inadvertent loss of contact and verifying that these conditions are fulfilled.
3.20
safe working load
maximum load that can be handled by the manual elevator (3.5) after subtracting the foreseeable
dynamic load for the specific application from its rated load
3.21
secondary feedback signal
other signal than primary feedback signal (3.16) generated by the elevator status that indicates any
other state than readiness for safe lifting (e.g. weight indication)
3.22
securing
fastening of the wrap-around of an elevator (3.5) around a tubular
EXAMPLE 1 To latch (completing a circle).
EXAMPLE 2 To set slips (3.26).
3.23
service life
expected lifetime, or acceptable period of use in service
Note 1 to entry: Service life is the length of time that the elevator (3.5) can be expected to be “serviceable” or to
be supported by the manufacturer.
3.24
short ton
ston
2
unit of weight equal to 9,071 847·10 kg
2
Note 1 to entry: 1 ton (US) = 1 ston = 9,071 847·10 kg.
3.25
size component
replaceable component which is required in order to handle a specific size and/or type of tubular
3.26
slip
tapered or wedge-shaped size component (3.25) used to grip the tubular, and whose exterior is tapered
to match the taper of the elevator frame
Note 1 to entry: A slip either has non-replaceable teeth or is fitted with inserts (3.8).
3.27
verification
assurance that the elevator (3.5) is in the required condition for the action
to be performed, for any position or any allowable user situation for which the elevator is designed
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ISO 20321:2020(E)

3.28
wrapping
closing the elevator around the tubular in order to prepare the elevator for securing
4 Abbreviated terms
ESD emergency shutdown
HMI human machine interface
MSDS material safety data sheet
PL performance level
SWL safe working load
5 Safety requirements and/or protective/risk reduction measures
5.1 General requirements for powered elevators
The powered elevator shall comply with ISO 13535 and the additional requirements according to this
document. The requirements of this document take precedence over those of ISO 13535.
The powered elevator shall be designed according to the principles of ISO 12100 for relevant but not
significant hazards which are not dealt with by this document.
5.2 Mechanical strength
The mechanical strength of the powered elevator shall be in accordance with ISO 13535:2000, Clause 5.
Adequate mechanical design shall be verified by a static test in accordance with ISO 13535:2000 and
Annex B.
5.3 Safety design of powered elevators
5.3.1 General
The powered elevator design and product verification shall be carried out in accordance with Annex B.
5.3.2 Ergonomic design
The powered elevator shall allow safe handling of the elevator during all stages of the transport,
installation and operation process.
5.3.3 Fastening methods and DROPS prevention of parts
5.3.3.1 Primary-fixing
Primary fixing is the primary method by which an item is fixed to prevent unintentional dropping or
falling, e.g. bolted connection/welds.
5.3.3.2 Securing against loosening (secondary retention)
Secondary retention is the method for securing a part from unintended loosening resulting in loss of
clamping force and/or pre-tension and/or unscrewing and/or displacement and/or loss of any part.
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ISO 20321:2020(E)

All parts for which unintended loosening can create a hazard shall be fastened with a method preventing
unintended loosening, e.g. by tab-washer, spring washer.
The reliability of the retention method shall be assessed in accordance with ISO 12100.
5.3.3.3 Securing against dropping (DROPS prevention)
Appropriate design measures shall be taken for all parts, which can become a hazardous dropped
object in case of component failure.
The reliability of the securing method shall be assessed in accordance with ISO 12100.
The causes of failure taken into account shall include:
a) vibration;
b) improper maintenance;
c) corrosion;
d) shock loading;
e) collision.
The potential for dropped objects/falling objects shall be prevented by measures including but not
limited to:
a) design;
b) speciality fasteners;
c) lanyards, cabling or safety wire;
d) guarding.
5.3.4 Suspension points
The powered elevator shall be designed so that it cannot inadvertently disconnect from its suspension
points regardless of the angle of rotation relative to the suspension points.
When the powered elevator has secondary suspension points for suspending another elevator
underneath, these suspension points shall be tested in accordance with B.2. The rating of each secondary
suspension point, determined in accordance with ISO 13535, shall be marked at the suspension point
sufficient to indicate the maximum load that can be applied.
5.3.5 Moving parts, pinch points and guards
The powered elevator shall be designed to provide safe operator contact with designated areas for
operation. The provisions made shall include at least the following.
a) Dedicated areas for placing hands for operating the elevator shall be coloured green by means of
paint, grip points or otherwise.
b) Handles shall be designed so that an operator cannot be injured by other parts of the elevator. If
interference is unavoidable, adequate protective measures such as guards shall be provided.
c) When other measures are not practical, warnings shall be displayed near or on identified potentially
hazardous pinch points.
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ISO 20321:2020(E)

Any hazardous areas reachable for a second operator not visible to the first operator, shall be protected
as follows:
— minimum gaps provided to avoid crushing shall comply with the requirements given in ISO 13854;
— guards or parts providing the function of a guard shall comply with the requirements given in
ISO 14120.
5.4 Other protective measures
5.4.1 Risks due to surfaces, edges or angles
Sharp edges, rough surfaces and sharp angles shall be avoided
...