ISO 21984:2018

Ships and marine technology - Guidelines for measurement, evaluation and reporting of vibration with regard to habitability on specific ships

ISO 21984:2018 gives guidelines for the measurement, evaluation and reporting of vibration with regard to habitability for all persons on board ships satisfying one or both of the following conditions: a) 2-stroke cycle, long-stroke, low-speed diesel engine directly coupled to the fixed-pitch propulsion propeller is installed. b) length of deck house (L) is limited as compared with its height (H) (i.e. deck house of around 1,0 and above in slenderness ratio of H to L). An example of length of deck house (L) and its height (H) for slenderness ratio is shown in Annex A. Overall frequency-weighted r.m.s. vibration values in the frequency range 1 Hz to 80 Hz are given as guidance values for different spaces on ships. ISO 21984:2018 is applicable to specific ships with intended voyages of 24 h or more. ISO 21984:2018 specifies requirements for the instrumentation and the procedure of measurement in normally occupied spaces. It also contains analysis specifications and guidelines for the evaluation of ship vibration with respect to habitability. This document is not applicable to machinery spaces, other than engine control rooms, where persons do not stay for prolonged periods of time. ISO 20283‑5 is generally applicable to all ships. Requirements for measurement, evaluation and reporting of vibration with regard to habitability for all persons on board passenger and merchant ships, including specific ships to which this document may also be applicable can be found in ISO 20283‑5. This document is neither complementary nor additional but supplementary to ISO 20283‑5. The shipbuilder can select either this document or ISO 20283‑5 to apply to any specific ship upon due consideration to individual design conditions of the ship and, if any, experience in building sister or similar ships, and that particular selection is intended to be agreed on by the shipowner. The evaluation of low-frequency ship motion which can result in motion sickness is covered by ISO 2631‑1. For the evaluation of the global structural vibration of a ship, however, see ISO 20283‑2.

Navires et technologie maritime — Lignes directrices pour le mesurage, l'évaluation et l'établissement de rapports des vibrations affectant l'habitabilité à bord des navires spéciaux

General Information

• Status: Published
• Publication Date: 01-Feb-2018
• ICS: 17.160 - Vibrations, shock and vibration measurements
• ICS: 47.020.01 - General standards related to shipbuilding and marine structures
• Technical Committee: ISO/TC 8/SC 8 - Ship design
• Drafting Committee: ISO/TC 8/SC 8 - Ship design
• Current Stage: 9093 - International Standard confirmed
• Start Date: 21-Jul-2023
• Completion Date: 13-Dec-2025

Overview - ISO 21984:2018 (Ships and marine technology - Vibration guidelines)

ISO 21984:2018 provides guidance for the measurement, evaluation and reporting of shipboard vibration with regard to habitability on specific ships. It targets vessels with intended voyages of 24 hours or more and applies where one or both of these conditions exist: a) a 2‑stroke, long‑stroke, low‑speed diesel engine directly coupled to a fixed‑pitch propeller; and/or b) a relatively slender deck house (height-to-length slenderness). The standard focuses on human comfort and habitability (crew and passengers) in normally occupied spaces, not on general machinery rooms (except engine control rooms).

Key topics and technical requirements

• Frequency range and weighting: Measurements are specified in the 1 Hz to 80 Hz band with frequency weighting W (per ISO 2631‑2) applied to all directions.
• Overall result metric: Results are reported as overall frequency‑weighted r.m.s. vibration values (velocity and/or acceleration) for habitability evaluation.
• Instrumentation: Measuring equipment must meet ISO 8041 requirements; calibration (at least every two years) and functional checks before/after measurement series are required.
• Measurement procedure:
  • Three translational axes (longitudinal, transverse, vertical) measured at key locations; vertical measurements required at most other locations.
  • Measurement duration: minimum 1 minute (recommended 2 minutes if significant components < 2 Hz).
  • Transducers mounted to capture the interface vibration between occupant and deck/floor (use of three‑spike plates or suitable mounting on soft floor coverings).
• Measurement conditions: Free‑route straight course, constant propulsion power and rotational speed, full propeller immersion, and normal operation of ship systems (HVAC, auxiliaries). Deviations must be recorded.
• Evaluation and reporting: Guidance values for acceptable vibration are provided for different spaces (accommodation, offices, wheelhouse, engine control room, open‑deck recreation, other work spaces). The test report must document locations, conditions, instrumentation, and any beating phenomena.

Applications and practical value

• Use ISO 21984:2018 to:
  • Verify that vibration levels meet habitability requirements during sea trials and acceptance tests.
  • Compare vibration performance across sister ships or design iterations.
  • Inform remedial measures (isolation, structural modification, operational changes) to improve onboard comfort.
• Typical users: shipbuilders, shipowners, naval architects, vibration engineers, owners’ representatives, and classification society surveyors involved in ship acceptance testing and habitability assessment.

Related standards

• ISO 20283‑5 - Habitability vibration measurement for passenger and merchant ships (alternative/supplementary approach)
• ISO 2631‑1 - Evaluation of human exposure to whole‑body vibration (low‑frequency motion)
• ISO 20283‑2 - Global structural vibration assessment of ships
• ISO 8041 - Instrumentation for human response to vibration
• ISO 2041 - Vibration and shock vocabulary

Keywords: ISO 21984:2018, ship vibration guidelines, habitability vibration, vibration measurement, frequency‑weighted r.m.s., marine technology, ISO 20283‑5, ISO 8041.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 21984
First edition
2018-02
Ships and marine technology —
Guidelines for measurement,
evaluation and reporting of vibration
with regard to habitability on
specific ships
Navires et technologie maritime — Lignes directrices pour le
mesurage, l'évaluation et l'établissement de rapports des vibrations
affectant l'habitabilité à bord des navires spéciaux
Reference number
©
ISO 2018
© ISO 2018, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
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Fax [phone]
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www.iso.org
ii © ISO 2018 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Instrumentation . 2
4.1 General requirements . 2
4.2 Functional test . 3
5 Measurement locations and directions . 3
5.1 Measurement locations . 3
5.2 Measurement directions . 3
6 Measurement conditions . 3
7 Measurement procedure . 4
8 Evaluation . 4
8.1 Guidance values of acceptable vibration . 4
8.2 Beating . 5
9 Test report . 5
Annex A (informative) Example of length of a deck house (L) and its height (H) for
slenderness ratio . 6
Annex B (informative) Frequency weighting, W . 7
m
Annex C (informative) Example of report for evaluation of habitability on board ships in
accordance with this document . 9
Bibliography .10
Foreword
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URL: www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology,
Subcommittee SC 8, Ship design.
iv © ISO 2018 – All rights reserved

Introduction
Shipboard vibration that interferes with duties or reduces comfort is objectionable and often results in
adverse comments from crew and passengers. To quantify this vibration, this document gives guidelines
for the measurement, evaluation and reporting of habitability for all persons on board specific ships
including crew.
Vibration data acquired in accordance with this document are also useful for
— comparison with ship specifications,
— comparison with other ships, and
— further development and improvement of vibration regulations.
INTERNATIONAL STANDARD ISO 21984:2018(E)
Ships and marine technology — Guidelines for
measurement, evaluation and reporting of vibration with
regard to habitability on specific ships
1 Scope
This document gives guidelines for the measurement, evaluation and reporting of vibration with regard
to habitability for all persons on board ships satisfying one or both of the following conditions:
a) 2-stroke cycle, long-stroke, low-speed diesel engine directly coupled to the fixed-pitch propulsion
propeller is installed.
b) length of deck house (L) is limited as compared with its height (H) (i.e. deck house of around 1,0
and above in slenderness ratio of H to L). An example of length of deck house (L) and its height (H)
for slenderness ratio is shown in Annex A.
Overall frequency-weighted r.m.s. vibration values in the frequency range 1 Hz to 80 Hz are given as
guidance values for different spaces on ships.
This document is applicable to specific ships with intended voyages of 24 h or more.
This document specifies requirements for the instrumentation and the procedure of measurement in
normally occupied spaces. It also contains analysis specifications and guidelines for the evaluation of
ship vibration with respect to habitability.
This document is not applicable to machinery spaces, other than engine control rooms, where persons
do not stay for prolonged periods of time.
ISO 20283-5 is generally applicable to all ships. Requirements for measurement, evaluation and
reporting of vibration with regard to habitability for all persons on board passenger and merchant ships,
including specific ships to which this document may also be applicable can be found in ISO 20283-5. This
document is neither complementary nor additional but supplementary to ISO 20283-5. The shipbuilder
can select either this document or ISO 20283-5 to apply to any specific ship upon due consideration to
individual design conditions of the ship and, if any, experience in building sister or similar ships, and
that particular selection is intended to be agreed on by the shipowner.
The evaluation of low-frequency ship motion which can result in motion sickness is covered by
ISO 2631-1. For the evaluation of the global structural vibration of a ship, however, see ISO 20283-2.
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 2041, Mechanical vibration, shock and condition monitoring — Vocabulary
ISO 2631-1, Mechanical vibration and shock — Evaluation of human exposure to whole-body vibration —
Part 1: General requirements
ISO 2631-2, Mechanical vibration and shock — Evaluation of human exposure to whole-body vibration —
Part 2: Vibration in buildings (1 Hz to 80 Hz)
ISO 8041, Human response to vibration — Measuring instrumentation
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 2041 and the following 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 https:// www .electropedia .org/
3.1
accommodation space
space intended for recreational and administration use, namely cabins including day and sleeping
rooms, hospitals, mess rooms, recreation rooms
Note 1 to entry: Examples of recreation rooms are lounges, smoke rooms, cinemas, gymnasiums, libraries, hobby
rooms and game rooms.
3.2
office
space or room for carrying out a ship’s business
EXAMPLE Deck office, ship office, meeting rooms.
3.3
work space
space allocated predominantly for manual work, namely workshops, laundries, galleys and laboratories,
but not machinery space (3.4)
3.4
machinery space
space which contains steam or internal-combustion machinery, pumps, air compressors, boilers, oil fuel
units, major electrical machinery, oil filling stations, thrusters, refrigerating, stabilizing, steering gear,
ventilation and air conditioning machinery, etc., and tr
...