SIST EN ISO 20650:2026

• Abstract:

  This document is applicable to small floating working machines used for work in, over, or on, inland waters. This document specifies safety-related requirements and test methods.; This document specifies minimum requirements for small floating working machines with a length of < 10 m and a product of length, width and depth of less than 30 m3, with temporarily or permanently installed work equipment or machines used on inland waters.; These small floating working machines can be used for activities such as extraction work, lifting work, sampling, mowing and clearing work or comparable tasks.

• Status: Published
• Public Enquiry End Date: 29-Apr-2026
• Publication Date: 12-Jul-2026
• ICS: 47.060 - Inland navigation vessels
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 08-Jul-2026
• Due Date: 12-Sep-2026
• Completion Date: 13-Jul-2026
• Ref Project: EN ISO 20650:2026 - Inland navigation vessels - Small floating working machines - Requirements and test methods (ISO 20650:2025)

• Refers: oSIST IEC 60364-5-54:2010 - Low-voltage electrical installations - Part 5-54: Selection and erection of electrical equipment - Earthing arrangements, protective conductors and protective bonding conductors
• Effective Date: 01-Jul-2026

Overview

SIST EN ISO 20650:2026 sets out comprehensive safety requirements and test methods for small floating working machines used on inland waters. Applicable to vessels less than 10 meters in length and with a hull volume under 30 m³, this international standard focuses on ensuring the safety, stability, and performance of machines equipped for various operations in rivers, lakes, and similar environments. The document is particularly relevant for boats engaged in extraction work, lifting, sampling, mowing, clearing, and comparable activities. Standardization under ISO 20650:2025 helps manufacturers, operators, and regulatory bodies improve safety and efficiency in the inland waterway workboat sector.

Key Topics

Critical Areas Covered by ISO 20650:2025:

• General Safety and Design Requirements: Ensures structural strength, stability, and watertightness to support safe operation in inland waters.
• Collision and Machinery Bulkheads: Specifications for watertight bulkheads to maintain buoyancy and flotation even if a compartment is flooded.
• Stability and Buoyancy: Requirements for minimum freeboard, residual safety clearance, and resistance to sinking, including tests and mathematical verification methods.
• Steering and Helm Systems: Outlines requirements for steering mechanisms, helm station visibility, and operator controls.
• Engine and Propulsion Systems: Sets out standards for propulsion-diesel, LPG, or electric-including safety features, exhaust, ventilation, and fire protection.
• Electrical Installations: Details on electrical safety, voltages, navigation lights, generators, batteries, switchgear, and cabling.
• Work Equipment: Guidance for the integration and safe use of accessories such as cranes, winches, and other temporarily or permanently installed machinery.
• Safety at Workstations: Provides measures for operator safety, including fall prevention, access, exits, emergency procedures, and noise/vibration reduction.
• Testing and Marking: Defines procedures for visual inspections, mechanical tests, and proper vessel marking with type plates.

Applications

The standard is essential for several types of inland navigation vessels and their operators, especially those using compact machines for:

• Dredging and Extraction: Machines equipped with dredging arms or pumps for sediment removal in rivers or lakes.
• Water Plant Management: Vessels for mowing aquatic plants to maintain navigable waterways.
• Sampling and Monitoring: Boats with scientific or environmental equipment for water quality sampling or ecological assessment.
• Lifting and Maintenance Work: Small cranes and lifting devices used for infrastructure repair, debris clearing, or bridge maintenance.
• Rescue and Emergency Operations: Specialized small workboats for search, rescue, or pollution control.

By adhering to these consolidated requirements and rigorous test methods, manufacturers, operators, and authorities ensure higher levels of safety, reliability, and operational readiness.

Related Standards

ISO 20650:2025 references and aligns with a range of related standards to provide a robust approach to inland waterway vessel safety and performance, including:

• ISO 7010: Safety signs and graphical symbols
• ISO 1035 series: Dimensions for steel bars
• ISO 2922 & ISO 2923: Measurement of noise emissions from vessels
• ISO 4254-1 & ISO 12100: Machinery safety and risk assessment
• ISO 7165: Fire extinguisher performance
• ISO 10240: Owner’s manual requirements for small craft
• ISO 12402-2 & ISO 12402-3: Lifejacket safety requirements
• ISO 13297: Electrical installations in small craft
• ISO 13857: Safety distances for machinery
• ISO 17631: Fire and life-saving plans for vessels
• IEC 60529: Degrees of protection (IP code)
• IEC 62619 & IEC 62620: Lithium battery safety for industrial use

These and other cross-references ensure that SIST EN ISO 20650:2026 remains aligned with best practices in maritime and machinery safety, electrical installations, and environmental protection-supporting harmonized safety standards for inland navigation workboats worldwide.

SLOVENSKI STANDARD
01-september-2026
Plovila za celinske vode - Majhni plavajoči delovni stroji - Zahteve in preskusne
metode (ISO 20650:2025)
Inland navigation vessels - Small floating working machines - Requirements and test
methods (ISO 20650:2025)
Fahrzeuge der Binnenschifffahrt - Kleine schwimmende Arbeitsmaschinen -
Anforderungen und Prüfverfahren (ISO 20650:2025)
Bateaux de navigation intérieure - Petites machines de travail flottantes - Exigences et
méthodes d’essai (ISO 20650:2025)
Ta slovenski standard je istoveten z: EN ISO 20650:2026
ICS:
47.060 Jezerska in rečna plovila Inland navigation vessels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 20650
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2026
EUROPÄISCHE NORM
ICS 47.060
English Version
Inland navigation vessels - Small floating working
machines - Requirements and test methods (ISO
20650:2025)
Bateaux de navigation intérieure - Petites machines de Fahrzeuge der Binnenschifffahrt - Kleine
travail flottantes - Exigences et méthodes d'essai (ISO schwimmende Arbeitsmaschinen - Anforderungen und
20650:2025) Prüfverfahren (ISO 20650:2025)
This European Standard was approved by CEN on 11 June 2026.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 20650:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 20650:2025 has been prepared by Technical Committee ISO/TC 8 "Ships and marine
technology” of the International Organization for Standardization (ISO) and has been taken over as
which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by December 2026, and conflicting national standards
shall be withdrawn at the latest by December 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 20650:2025 has been approved by CEN as EN ISO 20650:2026 without any modification.

International
Standard
ISO 20650
First edition
Inland navigation vessels — Small
2025-05
floating working machines —
Requirements and test methods
Reference number
ISO 20650:2025(en) © ISO 2025
ISO 20650:2025(en)
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 20650:2025(en)
Contents Page
Foreword .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 General requirements . 3
4.1 General requirements .3
4.2 Strength .3
4.3 Stability .4
4.4 Residual safety clearance.4
4.5 Residual freeboard .4
4.6 Sinking resistance .4
4.7 Draught marks .4
4.8 Manoeuvring characteristics . .4
4.9 Driving noise of the small floating working machine .4
4.10 Alarm signal .4
4.11 Stability and strength of working equipment .5
5 Steering system . 5
5.1 General .5
5.2 Drive unit of the steering system . .5
5.3 Indicators and monitoring devices .5
5.4 Penetrations for the rudder stocks .5
6 Helm station . 6
6.1 General .6
6.2 Unobstructed view .6
6.3 Control, indicating and monitoring equipment .8
6.3.1 General requirements .8
6.3.2 Specific requirements concerning control and monitoring equipment of main
engines .8
6.4 Elevating helm stations .8
7 Engine rooms . 9
7.1 General .9
7.2 Fire protection .9
7.3 Heat detector .9
8 Requirements on engine design . 9
8.1 General .9
8.2 Safety equipment .9
8.3 Propulsion systems .9
8.4 Engine exhaust systems of internal combustion engines .10
8.5 Fuel tanks, pipes and accessories for liquid fuels or hydraulic oils.10
8.6 Tanks, pipes and accessories for LPG .10
8.6.1 General .10
8.6.2 Cylinders .11
8.6.3 Fuel system components .11
8.6.4 Installation .11
8.6.5 Installation of cylinders . 12
8.6.6 Gas pipes and hoses . 13
8.6.7 Electro installation.14
8.6.8 Gas detection .14
8.6.9 Forced ventilation . 15
8.7 Bilge pumping and draining systems . 15
8.8 Penetrations for the propeller shafts . 15
9 Electrical equipment and installations .15

iii
ISO 20650:2025(en)
9.1 General . 15
9.2 Protection against access to hazardous parts, against solid foreign objects, against
ingress of water .16
9.3 Maximum permissible voltages . .16
9.4 Generators, engines and transformers .17
9.5 Accumulators (batteries) and their charging devices .17
9.6 Switchgears .19
9.6.1 Switchboards .19
9.6.2 Switches, protective devices .19
9.6.3 Placement of switchboards .19
9.7 Installation fittings .19
9.8 Cables, insulated cables and cable systems .19
9.9 Lighting installations . 20
9.10 Navigation lights . 20
9.11 Additional requirements for electronic installations . 20
10 Special provisions applicable to electric vessel propulsion motor .20
10.1 General . 20
10.2 Generators, transformers and switchgear for electric vessel propulsion .21
10.3 Electric propulsion engines for electric propulsion .21
10.4 Power electronics for electric vessel propulsion .21
10.5 Monitoring equipment . 22
10.6 Control, regulation and automatic power limitation . 22
10.7 Protection of the electric vessel propulsion . 22
11 Equipment .23
11.1 Lifebuoys and lifejackets . 23
11.2 Anchor equipment . 23
11.3 Portable fire extinguishers . . 23
11.4 Additional equipment . 23
12 Safety at workstations .24
12.1 General .24
12.2 Protection against falling .24
12.3 Access to workstations . 25
12.4 Exits and emergency exits. 26
12.5 Ladders, steps and similar devices . 26
12.6 Interior rooms . 26
12.7 Protection against noise and vibration . 26
13 Working gear .27
13.1 Accessory equipment .27
13.2 Mobile and temporary machinery/work equipment .27
13.3 Winches .27
13.4 Cranes .27
14 Fuel-fired heating equipment .28
15 Owner’s manual .29
15.1 Basics . 29
15.2 Range of use . 29
15.3 References to tests to be carried out during operation . 29
15.4 Cranes . 29
15.4.1 Cranes operating instructions . 29
15.4.2 Periodic inspection of cranes by an expert . 29
15.4.3 Regular checks of cranes by a competent person . 30
15.5 Electric propulsion. 30
16 Marking of small floating working machines (machine type plate) .30
17 Testing.30
17.1 General . 30
17.1.1 Range . 30

iv
ISO 20650:2025(en)
17.1.2 Individual testing and type testing . 30
17.1.3 Specimen selection for type testing . 30
17.2 Basic tests .31
17.2.1 Visual inspection and measurement .31
17.2.2 Presentation of manufacturer's certificates.31
17.3 Strength .31
17.4 Stability .31
17.5 Safety against sinking .31
17.6 Manoeuvring characteristics . .31
17.7 Noise limit values .31
17.8 Cranes .32
17.9 Electrical propulsion .32
17.10 Stairs .32
17.11 Climbing devices .32
Annex A (normative) Proof of stability .33
Annex B (normative) Manoeuvrability .36
Annex C (normative) Safety requirements on stairs and ladders .37
Annex D (normative) Safety requirements for winches . 41
Bibliography .44

v
ISO 20650:2025(en)
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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 8, Ships and marine technology, Subcommittee
SC 7, Inland navigation vessels.
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.

vi
International Standard ISO 20650:2025(en)
Inland navigation vessels — Small floating working machines
— Requirements and test methods
1 Scope
This document is applicable to small floating working machines used for work in, over, or on, inland waters.
This document specifies safety-related requirements and test methods.
This document specifies minimum requirements for small floating working machines with a length of < 10 m
and a product of length, width and depth of less than 30 m , with temporarily or permanently installed work
equipment or machines used on inland waters.
These small floating working machines can be used for activities such as extraction work, lifting work,
sampling, mowing and clearing work or comparable tasks.
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 1035-1, Hot-rolled steel bars — Part 1: Dimensions of round bars
ISO 1035-2, Hot-rolled steel bars — Part 2: Dimensions of square bars
ISO 1035-3, Hot-rolled steel bars — Part 3: Dimensions of flat bars
ISO 2922, Acoustics — Measurement of airborne sound emitted by vessels on inland waterways and harbours
ISO 2923, Acoustics — Measurement of noise on board vessels
ISO 4254-1, Agricultural machinery — Safety — Part 1: General requirements
ISO 7010, Graphical symbols — Safety colours and safety signs — Registered safety signs
ISO 7165, Fire fighting — Portable fire extinguishers — Performance and construction
ISO 9519, Ships and marine technology — Single rungs and rungs for dog-step ladders
ISO 10240, Small craft — Owner’s manual
ISO 11102-1, Reciprocating internal combustion engines — Handle starting equipment — Part 1: Safety
requirements and tests
ISO 11105, Small craft — Ventilation of petrol engine and/or petrol tank compartments
ISO 12100, Safety of machinery — General principles for design — Risk assessment and risk reduction
ISO 12402-2, Personal flotation devices — Part 2: Lifejackets, performance level 275 — Safety requirements
ISO 12402-3, Personal flotation devices — Part 3: Lifejackets, performance level 150 — Safety requirements
ISO 13297, Small craft — Electrical systems — Alternating and direct current installations
ISO 13857, Safety of machinery — Safety distances to prevent hazard zones being reached by upper and lower limbs

ISO 20650:2025(en)
ISO 14895, Small craft — Liquid-fuelled galley stoves and heating appliances
ISO 16180, Small craft — Navigation lights — Installation, placement and visibility
ISO 17631:2022, Ships and marine technology — Shipboard plans for fire control, damage control, life-saving
appliances and means of escape
ISO 18422, Ships and marine technology — Inland navigation vessels — Plate with instructions for rescue,
resuscitation and first aid for drowning persons
IEC 60092-504, Electrical installations in ships — Part 504: Automation, control and instrumentation
IEC 60364-5-54, Low-voltage electrical installations — Part 5-54: Selection and erection of electrical equipment
— Earthing arrangements and protective conductors
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 61000-4-2, Electromagnetic compatibility (EMC) — Part 4-2: Testing and measurement techniques —
Electrostatic discharge immunity test
IEC 61000-4-3, Electromagnetic compatibility (EMC) — Part 4-3: Testing and measurement techniques —
Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-4-4, Electromagnetic compatibility (EMC) — Part 4-4: Testing and measurement techniques —
Electrical fast transient/burst immunity test
IEC 62619, Secondary cells and batteries containing alkaline or other non-acid electrolytes — Safety
requirements for secondary lithium cells and batteries, for use in industrial applications
IEC 62620, Secondary cells and batteries containing alkaline or other non-acid electrolytes — Secondary lithium
cells and batteries for use in industrial applications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
small floating working machine
watercraft used on inland waters with a hull whose length is less than 10 m and whose product of length,
width and depth of less than 30 m , with temporarily or permanently installed working equipment or
machinery
EXAMPLE Mowing boats, watercraft for sampling, extraction work, keeping waters clean, lifting work.
3.2
residual safety clearance
shortest vertical distance between surface of the water and the lowest part of the small floating working machine
(3.1) beyond which it is no longer watertight, taking into account trim and heel resulting from the moments
3.3
residual freeboard
smallest vertical distance between the surface of the water and the upper surface of the deck at its edge
taking into account trim and heel
3.4
working area
area of inland water, where the work is carried out

ISO 20650:2025(en)
3.5
operating range
driving range from the berth to the working area (3.4), and from/to the working area itself
3.6
propulsion system
system consisting of internal combustion engine and/or electric drive engine with power source including
power electronics, gearbox, shaft, propeller, etc., used to move the craft in the water
3.7
propulsion
diesel, LPG (liquified petroleum gas), electric or diesel or gas-electric propulsion system (3.6) of a small
floating working machine (3.1) containing at least one propulsion engine (3.9)
3.8
main propulsion
propulsion (3.7) used to achieve the manoeuvring characteristics
3.9
propulsion engine
engine for driving the propeller shaft or the shaft of comparable drive systems such as water jet drives
3.10
expert
person recognised by the competent authority or by an authorised institution, having specialist knowledge
in the relevant area on the basis of his or her professional training and experience, fully conversant with
the relevant rules and regulations and the generally accepted technical rules (e.g. ISO standards, relevant
regulations, technical rules), and able to examine and give a thorough and knowledgeable assessment of the
relevant systems and equipment
3.11
competent person
person who has acquired sufficient knowledge in the relevant area on the basis of his or her professional
training and experience and is sufficiently conversant with the relevant rules and regulations and the
generally accepted technical rules (such as ISO standards, relevant regulations, technical rules) to be able to
assess the operational safety of the relevant systems and equipment
4 General requirements
4.1 General requirements
Small floating working machines shall be built in accordance with the manufacturer’s specification.
At least one watertight collision bulkhead and one machinery space bulkhead shall be fitted up to the deck
or to the upper edge of the ship’s side. The collision bulkhead shall be installed at an appropriate distance
from the bow so that when the watertight compartment forward of the collision bulkhead is flooded, the
buoyancy of the fully loaded vessel is maintained and a residual safety clearance of not less than 300 mm is
maintained.
4.2 Strength
The strength of small floating machines shall be sufficient to withstand the stresses to which they are
exposed, under the conditions of use specified by the manufacturer.
When using steel S 235 B according to ISO 630-2, the requirement above is fulfilled if the thickness of
the bottom and side plates is at least 3 mm. If other materials or lower material thicknesses are used, a
mathematical verification is required.

ISO 20650:2025(en)
4.3 Stability
The stability of small floating machines shall withstand the stresses to which they are exposed, under the
conditions of use specified by the manufacturer.
The stability of a small floating machinery shall be sufficient for the loads to which it is subjected, under
the conditions of use specified by the manufacturer. It shall be demonstrated mathematically by the test
conditions given in Annex A.
For small floating working machines where no change in heel or trim can be caused by their working
equipment and where a shift in the centre of gravity can be ruled out as far as possible, a mathematical
verification may be dispensed with.
4.4 Residual safety clearance
The residual safety clearance shall be at least 300 mm.
4.5 Residual freeboard
The residual freeboard shall be at least 300 mm.
4.6 Sinking resistance
Small floating working machines shall be safe against sinking in the event of flooding of one watertight
compartment.
The residual buoyancy force at the end of flooding of any compartment of the small floating working machine
shall be at least 100 N for each designated crew member.
4.7 Draught marks
The plane of maximum draught shall be marked on each side at each end of the small floating working
machine by indelible draught marks in a contrasting colour. These shall consist of a rectangle measuring
150 mm × 30 mm (L × H), with the base line horizontal and coinciding with the plane of the maximum
allowed draught.
4.8 Manoeuvring characteristics
Small floating working machines shall:
— have adequate driving and manoeuvring characteristics in accordance with Annex B;
— be able to reach a minimum speed of 4 km/h in relation to the water in the travel range.
4.9 Driving noise of the small floating working machine
The noise emitted by a small floating working machine under way at a lateral distance of 25 m from the
craft’s side shall not exceed 75 dB(A) measured in accordance with ISO 2922.
4.10 Alarm signal
There shall be an alarm signal that can warn all persons on board in case of general emergency.
The alarm signal shall be clearly distinguishable from other signals. It shall produce a sound pressure level
at all workstations that is at least 5 dB(A) higher than the maximum local sound pressure level.

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