EN ISO 19901-5:2016

SLOVENSKI STANDARD
01-maj-2016
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SIST EN ISO 19901-5:2004
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Petroleum and natural gas industries - Specific requirements for offshore structures -
Part 5: Weight control during engineering and construction (ISO 19901-5:2016)
Erdöl- und Erdgasindustrie - Besondere Anforderungen an Offshore-Bauwerke - Teil 5:
Gewichtskontrolle während der Auslegung und Konstruktion (ISO 19901-5:2016)
Industries du pétrole et du gaz naturel - Exigences spécifiques relatives aux structures
en mer - Partie 5: Contrôle des poids durant la conception et la fabrication (ISO 19901-
5:2016)
Ta slovenski standard je istoveten z: EN ISO 19901-5:2016
ICS:
75.180.10 Oprema za raziskovanje in Exploratory and extraction
odkopavanje equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 19901-5
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2016
EUROPÄISCHE NORM
ICS 75.180.10 Supersedes EN ISO 19901-5:2003
English Version
Petroleum and natural gas industries - Specific
requirements for offshore structures - Part 5: Weight
control during engineering and construction (ISO 19901-
5:2016)
Industries du pétrole et du gaz naturel - Exigences Erdöl- und Erdgasindustrie - Besondere
spécifiques relatives aux structures en mer - Partie 5: Anforderungen an Offshore-Bauwerke - Teil 5:
Contrôle des poids durant la conception et la Gewichtskontrolle während der Auslegung und
fabrication (ISO 19901-5:2016) Konstruktion (ISO 19901-5:2016)
This European Standard was approved by CEN on 30 January 2016.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 19901-5:2016 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
European foreword
This document (EN ISO 19901-5:2016) has been prepared by Technical Committee ISO/TC 67
"Materials, equipment and offshore structures for petroleum, petrochemical and natural gas industries"
in collaboration with Technical Committee CEN/TC 12 “Materials, equipment and offshore structures
for petroleum, petrochemical and natural gas industries” the secretariat of which is held by NEN.
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 September 2016, and conflicting national standards
shall be withdrawn at the latest by September 2016.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document supersedes EN ISO 19901-5:2003.
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, Former Yugoslav Republic of Macedonia, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands,
Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 19901-5:2016 has been approved by CEN as EN ISO 19901-5:2016 without any
modification.
INTERNATIONAL ISO
STANDARD 19901-5
Second edition
2016-02-15
Petroleum and natural gas
industries — Specific requirements
for offshore structures —
Part 5:
Weight control during engineering
and construction
Industries du pétrole et du gaz naturel — Exigences spécifiques
relatives aux structures en mer —
Partie 5: Contrôle des poids durant la conception et la fabrication
Reference number
ISO 19901-5:2016(E)
©
ISO 2016
ISO 19901-5:2016(E)
© ISO 2016, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

ISO 19901-5:2016(E)
Contents Page
Foreword .v
0 Introduction .vi
1 Scope . 1
2 Normative references . 1
3  Terms and definitions . 2
4 Abbreviated terms . 8
5 Weight control classes . 8
5.1 General . 8
5.2 Class A: High definition of weight and CoG . 8
5.3 Class B: Medium definition of weight and CoG. 8
5.4 Class C: Low definition of weight and CoG . 9
5.5 Selection of class of weight control . 9
6 Weight and load budget (WLB).10
6.1 General .10
6.2 Requirements .11
6.3 Content .11
6.3.1 General.11
6.3.2 Weight reserves .12
6.3.3 Future weights and loads .13
6.3.4 Loading conditions and parameters .13
6.3.5 Formats and levels.14
6.3.6 CoG envelopes .14
7 Weight control procedure .15
8 Weight reporting .16
8.1 General .16
8.2 Weight report requirements .17
9  Requirements for suppliers’ weight data and weighing of equipment and bulks .20
9.1 General .20
9.2 Provision of weight information .20
9.3 Weighing requirements .20
9.4 Weighing equipment .21
9.5 Weighing procedure .21
9.6 Notification and witnessing of weighing .22
9.7 Calibration of weighing equipment .22
9.8 Weighing operation .22
9.9 Temporaries during weighing .23
9.10 Items not installed during weighing .23
10  Requirements for weighing of major assemblies .23
10.1 Weighing procedure .23
10.2 Environmental conditions .23
10.2.1 Light .23
10.2.2 Wind .24
10.2.3 Temperature and humidity .24
10.3 Weighing .25
10.3.1 Number and timing of weighing .25
10.3.2 Weighing procedure .25
10.3.3 Notification and witnessing of weighings .26
10.3.4 Preparation of the weighing.26
10.3.5 Weighing equipment .27
10.3.6 Calibration of weighing system .30
ISO 19901-5:2016(E)
10.3.7 Weighing foundation and supports .30
10.3.8 Structural integrity .31
10.3.9 Weighing operation .31
10.3.10 CoG calculations .32
10.3.11 Weighing certificate.33
10.3.12 Weighing report .33
11  Requirements for “as-built” weight documentation .34
Annex A (informative) Weight data sheets — Tagged equipment .35
Annex B (informative) Weighing certificates .37
Annex C (informative) Weight and load budget (WLB) formats and levels .41
Annex D (informative) Major elements of the weight displacement .42
Annex E (informative) Supplier weighing procedure.43
Annex F (informative) Guidelines for displacement measurement of floaters .45
Annex G (informative) Requirements for weight control during operations .49
Annex H (informative) Requirements for topside weight estimation — New builds/green field .65
Annex I (informative) Executive summary description .70
Annex J (informative) Weighing result uncertainty .72
Annex K (informative) Weight control database structure .73
Bibliography .75
iv © ISO 2016 – All rights reserved

ISO 19901-5:2016(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 on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 67, Materials,equipment and offshore structures
for petroleum, petrochemical and natural gas industries, Subcommittee SC 7, Offshore structures.
This second edition cancels and replaces the first edition (ISO 19901-5:2003), which has been technically
revised.
ISO 19901 consists of the following parts, under the general title Petroleum and natural gas industries —
Specific requirements for offshore structures:
— Part 1: Metocean design and operating considerations
— Part 2: Seismic design procedures and criteria
— Part 3: Topsides structure
— Part 4: Geotechnical and foundation design considerations
— Part 5: Weight control during engineering and construction
— Part 6: Marine operations
— Part 7: Stationkeeping systems for floating offshore structures and mobile offshore units
— Part 8: Marine soil investigations
The following parts are under preparation:
— Part 9: Structural integrity management
ISO 19901-5:2016(E)
0 Introduction
0.1 General
The International Standards ISO 19900 to ISO 19906 relating to offshore structures constitute a
common basis covering those aspects that address design requirements and assessments of all offshore
structures used by the petroleum and natural gas industries worldwide. Through their application the
intention is to achieve reliability levels appropriate for manned and unmanned offshore structures,
whatever the type of structure and the nature of the materials used.
It is important to recognize that structural integrity is an overall concept comprising models for
describing actions, structural analyses, design rules, safety elements, workmanship, quality control
procedures and national requirements, all of which are mutually dependent. The modification of one
aspect of design in isolation can disturb the balance of reliability inherent in the overall concept or
structural system. The implications involved in modifications, therefore, need to be considered in
relation to the overall reliability of all offshore structural systems.
ISO 19900 to ISO 19906 relating to offshore structures are intended to provide a wide latitude in the
choice of structural configurations, materials and techniques without hindering innovation. Sound
engineering judgement is therefore necessary in the use of these International Standards.
0.2 Preface
It is proposed to canvass the TC 67/SC 7 member countries to widen the scope of this part of ISO 19901
for the third edition. As a consequence, the title might change.
— It is proposed to expand and re-structure this part of ISO 19901 to more comprehensively address
topsides weight engineering principles, roles, responsibilities and objectives for a complete platform
life cycle.
— It is proposed to re-format into a more traditional ISO document layout.
— The use of weight class A, B and C tables will be reviewed.
— There will be an outline of how to control topside weight, and of the aims and expectations of a
Weight Review Panel (or similar).
— A common topside operating philosophy will be included with a matrix of coincident drilling loads,
operating loads, and laydown / storage loads to be included in topside weight databases.
— It is proposed to give guidance on applied design contractor allowances during detailed design, plus
the use of client operational and management reserves.
— The weight and CoG accuracy expected from weighings will be addressed.
— Separate clauses will be added to give clarity to specific requirements of floating structures and
jackets
— The contents and terminology will be coordinated to interface with ISO 19902, Design of offshore
structures, and the forthcoming ISO19901-9, Structural integrity management (due to be published
in 2017).
It is proposed to give more guidance on a range of topics encountered during the phases of a platform
life cycle, typically:
a) Weight control principles
Overview of principles, aims and objectives
Roles and responsibilities
Competency
vi © ISO 2016 – All rights reserved

ISO 19901-5:2016(E)
Software selection
Deliverables for each project phase
Weight report contents
b) Floating structures and jackets
Specific requirements for floating structures
c) Concept and feasibility phase
Use of historical volumetric weight norms
Use of area based weight calculations
Use of footprint ratios
d) Front end engineering design phase
Design parameters to be fixed prior to setting Not-to-Exceed weights
e) Detailed design phase
Control of weight using a Weight Review Panel or similar
Use of contractor allowances
Use of client reserves
Discipline reporting responsibilities
Coincident operating loads
Coincident drilling loads
Coincident laydown and storage loads
Laydown and storage drawings and area signage
Vendor weighing requirements
f) Fabrication phase
Fabricator responsibilities
Reporting of site run materials
Weighing requirements
Preparations for weighing
Expected weight and CoG accuracy from weighings
Predictions and witnessing of weighings
Post-weighing reconciliation and weighing corrections
g) Installation and hook-up phase
Reporting of hook-up weights
h) Operational phase
Control of weight and CoG for topside modifications
ISO 19901-5:2016(E)
Interfaces with ISO 19901-9 and ISO 19902
i) Decommissioning phase
Preparations for decommissioning
Some of the above proposed changes are outlined in Annex G of this document (informative).
It is proposed that preparation of the third edition of this part of ISO 19901 will begin immediately
after the issue of this edition with a target publication date of 2017.
viii © ISO 2016 – All rights reserved

INTERNATIONAL STANDARD ISO 19901-5:2016(E)
Petroleum and natural gas industries — Specific
requirements for offshore structures —
Part 5:
Weight control during engineering and construction
1 Scope
This part of ISO 19901 specifies requirements for controlling the weight and centre of gravity
(CoG) by means of mass management during the engineering and construction of structures for the
offshore environment. The provisions are applicable to offshore projects that include structures of all
types (fixed and floating) and materials. These structures can be complete new installations or the
modifications to existing installations. Maintaining the weight control of existing installations is not
part of the main body of this part of ISO 19901, but some guidance on this is included in the Annex G.
This part of ISO 19901:
— specifies quality requirements for reporting of weights and centres of gravity;
— specifies requirements for weight reporting;
— provides a basis for overall project weight reports or management reports for all weight control
classes;
— specifies requirements for weight and load budgets;
— specifies the methods and requirements for the weighing and the determination of weight and CoG
of major assemblies;
— specifies requirements for weight information from suppliers, including weighing of equipment and
bulk materials for offshore installations.
It can be used:
— as a basis for planning, evaluating and presenting the client’s, contractor’s or fabricator’s weight
management and reporting system;
— as a means of refining the structural analysis or model;
— as a contract reference between client, contractor and suppliers;
— as a basis for costing, scheduling or determining suitable fabrication method(s) or location(s).
2 Normative references
The following referenced documents are indispensable for the application 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/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
ISO 19901-5:2016(E)
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
assembly
designed and fabricated group of bulk and equipment items which form one unit
3.2
budget weight
weight reference figures as defined in the weight and load budget and related to the initial or changed
design concept
3.3
bulk
component or arrangement of components defined as stock materials or of low complexity
Note 1 to entry: Bulk items support the equipment items by providing infrastructure around and between them.
3.4
centre of gravity
CoG
average location of the weight of an item
Note 1 to entry: For assemblies, modules or topsides, the aggregate CoG is the mathematical weighted average
of the CoGs of the individual items (comprising the completed assembly, module or topsides) measured from a
common reference point.
3.5
client
organisation for which a weight report is prepared
Note 1 to entry: This is the project owner (oil company/operator, fabricator, engineering sub-contractor,
lift/transportation contractor, etc.).
3.6
client weight reserve
weight addition (usually a lump sum weight) controlled by the client and used to account for any orders
for variation to the contractual design concept
3.7
CoG envelope
defined constraint volume within which the centre of gravity (CoG) of an assembly shall remain
3.8
consumables
variable content that does not remain at a constant level due to consumption during the operation of an
offshore installation
EXAMPLE Potable/service water, diesel fuel, crew provisions, bulk drilling powders for creation of mud
and/or cement.
3.9
contents
fluids or bulk powders held within bulks (piping or structural tanks) or equipment at their normal
operating levels
Note 1 to entry: Typical contents are hydrocarbons, cooling and heating mediums, chemicals, fuels, condensates,
seawater, fresh water, dry powders (drilling cement and mud additives), dry stores for workshops, sack stores,
etc. Fluids that are expected to be continuously installed in an item of equipment (e.g. coolants and lubricating
oils) are not to be considered as contents. See dry weight (3.16) for further explanation.
2 © ISO 2016 – All rights reserved

ISO 19901-5:2016(E)
3.10
contractor
organization tasked with constructing a portion of, or an overall project facility
3.11
contractor weight reserve
additional weight (either a lump sum weight or percentage of a total weight) at a specified CoG,
controlled by the contactor and used to account for any design growth within their control
3.12
deadweight
total carrying capacity of a floating structure
Note 1 to entry: Includes weight of crude oil, deck cargo, temporaries, water, snow and ice accumulations, marine
growth, ballast water, consumables, crew and their effects.
Note 2 to entry: See Annex D.
3.13
discipline
discrete branch of engineering reflecting a single aspect in the project
EXAMPLE Architectural, drilling, electrical, HVAC, instrumentation, loss control (safety), piping, structural
and telecommunications.
3.14
discipline check list
document detailing the weight items that are within the discipline’s control
3.15
displacement
weight of the volume of water displaced by a floating structure
Note 1 to entry: The sum of lightweight and deadweight including mooring system load, appendences and/or
appurtenances e.g. structures outside the moulded hull
Note 2 to entry: See Annex D.
3.16
dry weight
weight of a component, weight item or an assembly in its dry installed condition including permanent
utilities
Note 1 to entry: Examples of permanent utilities are gearbox oil, hydraulic oil, filter sand.
Note 2 to entry: Any content of operating fluid flowing through a component, weight item or an assembly is
excluded.
3.17
equipment
component or arrangement of components, built for specific function(s)
Note 1 to entry: The component/assembly normally has unique documentation due to its function and complexity.
Note 2 to entry: Refer to tagged equipment (3.41) for further explanation.
3.18
estimated weight
weight determined based on previous experience
ISO 19901-5:2016(E)
3.19
first fill
initial filling of specific contents in items of equipment or piping prior to start of operation of an offshore
facility
Note 1 to entry: First fill typically takes place towards the end of site construction, prior to tow-out and prior to
filling for normal operations.
3.20
float-out
loading condition in which a major assembly is transferred from a dry construction site to become self-
floating
3.21
future weight
weight of a component or an assembly to be installed after the start of production
3.22
grillage
steel structure, secured to the deck of a barge or vessel, designed to support the cargo and distribute
the loads between the cargo and the barge or vessel
3.23
gross weight
sum of the net weight and weight allowances
3.24
hook-up
installation of components or assemblies after the modules have been installed in their final position, to
connect to the existing installation
3.25
hook weight
sum of component, assembly or module lift weight and lifting gear
3.26
operating
at the start of steady-state production
Note 1 to entry: All bulk and equipment items are present with contents at nominal operating levels.
3.27
lifting gear
equipment needed during a lifting operation
EXAMPLE Slings, spreader bars, lifting frames, shackles.
3.28
lift weight
weight of a component, assembly or a module, including temporaries and residual fluid content but
excluding lifting gear
3.29
lightship weight
dry and invariable weight of a floating unit, including minimum utility content to secure a safe condition
Note 1 to entry: See Annex D.
4 © ISO 2016 – All rights reserved

ISO 19901-5:2016(E)
3.30
loading condition
defined event for which a weight and CoG need to be controlled
Note 1 to entry: For each loading condition, all weight items and variable loads that are known or predicted to
occur are identified, quantified and located.
Note 2 to entry: Typical loading conditions are dry installed offshore, float-out at assembly site, future operating
installed offshore, operating installed offshore, load-out to offshore transport vessel, transport to offshore field, etc.
3.31
load-out
transfer by way of horizontal movement of an assembly, module or topsides from its land-based
fabrication site onto a floating or grounded transport barge or vessel
Note 1 to entry: The following are typical load-out operations:
— skidded: load-out using a combination of skid-ways, skid-shoes or runners, propelled by towing engines,
jacks or winches;
— trailer: load-out using multi-axle trailers [self-propelled modular transporter (SPMT)].
3.32
master equipment list
MEL
project -specific database for control and management of technical data for tagged equipment
3.33
mating
transfer of a major assembly supported on barge(s) or vessel(s) to a temporary or permanent support
structure
3.34
module
major assembly of items forming a major building block which needs to be controlled with respect to
weight and CoG
3.35
net weight
calculated or estimated weight of an item excluding allowances
3.36
not-to-exceed weight
NTE weight
maximum acceptable weight for any given loading condition, with an associated limiting CoG envelope
3.37
operating weight
sum of the dry weight and the content weight
3.38
project management
management personnel tasked with implementing weight policy, objectives and
procedures
3.39
residual content
content in bulks and equipment remaining after testing or commissioning, and being present during
the subsequent loading conditions up to the start of production
ISO 19901-5:2016(E)
3.40
sea fastening
items used for temporary fastening to keep all items in position during transportation at sea
3.41
tagged equipment
equipment identified and labelled in accordance with the project coding manual and tracked in MEL
3.42
temporary items
temporaries
items temporarily installed during a loading condition and removed afterwards
Note 1 to entry: Temporaries do not form part of a structure’s permanent dry or operating weight.
3.43
test weight
sum of the dry weight plus the content required to test the equipment or assembly
3.44
tow-out
towing of a complete floating structure to the offshore installation site
3.45
transport
transfer of an assembly or module from one inshore or at shore location to another
location, or to the offshore installation site
3.47
weight allowance
weight additions to account for expected general growth due to immaturity of the current project stage
and/or components which are not estimated in detail at the current project stage
3.48
weight and load budget
WLB
document defining the weight and CoG limits for each loading condition, major assembly (and disciplines
for the dry installed offshore load condition)
Note 1 to entry: The WLB are to act as a comparison reference for:
a) weight, load and CoG control and reporting for the duration of the project through the engineering,
construction, installation and operation phases;
b) structural capacity requirements for individual sections or modules and for the total topsides or supporting
structure;
c) temporary and permanent bearing capacity and stability of the total facility;
d) overall cost and schedule control.
3.49
weight item
item or collection of bulk and/or equipment, content or assembly identified for weight reporting
purposes
6 © ISO 2016 – All rights reserved

ISO 19901-5:2016(E)
3.50
weight management
all planned and controlled activities which deal with:
— definition and publication of the project weight procedures, objectives and policies;
— identification of information about and evaluation of alternative design solutions;
— selection and implementation of an optimal design with respect to weight, CoG, volume, functionality,
cost and progress;
— monitoring and reporting weight data throughout the complete life cycle of an installation to assess
present and potential weight status
Note 1 to entry: Project management, engineering disciplines and weight control discipline shall cooperate and
participate to influence the weight management process by means of adequate working methods and tools.
3.51
weight objective
defined set of engineering goals necessary to fulfil the project contractual weight/CoG requirements
and intentions in order to contribute to the correct design quality as defined by the management
3.52
weight phase code
code used to identify the loading conditions in which a weight item is present
3.53
weight policy
statement from the project management, based on the weight objective, defining how the weight
objective is to be achieved
Note 1 to entry: As a minimum, the policy should include:
— the importance of the weight objective to the project aims and results;
— the priority, profile and control of weights at different levels in the project;
— a philosophy for responsibility and authority within and between project groups engaged in weight matters
3.54
weight report
regularly issued project document that details the weight and CoG for required assemblies and load
conditions based on best available information
Note 1 to entry: This document provides the basic load case for the project Structural Integrity models.
3.55
weight status code
code, based on the maturity of the design, used to identify the level of accuracy of the weight of a
weight item
Note 1 to entry: The weight status code is often used to assess the value of the weight allowance applied. As a
design matures, the weight status code will change so that an item’s weight allowance is reduced.
ISO 19901-5:2016(E)
4 Abbreviated terms
CoG Centre of Gravity
FEED Front End Engineering Design
MEL Master Equipment List
NTE Not to Exceed
WLB Weight and Load Budget
WTO Weight Take-Off
5 Weight control classes
5.1 General
In order to select the most appropriate level for weight control and reporting according to the degree of
weight and/or CoG sensitivity of the project, three classes of weight control have been defined. These
classes may also be used to determine the level of effort required in the weight management activities
for a project.
The tender documents and final contract shall specify the applicable weight control class, so that the
contractor can allocate the required resources.
5.2  Class A: High definition of weight and CoG
Class A shall apply if the project is weight and/or CoG sensitive for any of the anticipated loading cases,
or has many contractor interfaces.
Class A weight projects shall:
a) regardless of the source, have full traceability of all weight and CoG data;
b) record weight and CoG data using a relational database from the commencement of detail
engineering, with integration of suppliers’, fabricators’ and weighing results into the system;
c) verify the calculated weight and CoG of assemblies, modules or topsides by means of physical
weighings;
d) update weight data per weight item produced during the design phases to “as-built” status during
the fabrication.
5.3  Class B: Medium definition of weight and CoG
Class B shall apply to projects where the focus on weight and CoG is less critical for any of the anticipated
loading cases than for projects where Class A is applicable.
Class B weight projects shall:
a) based on the complexity of the project, determine whether a relational database or spread sheet
software is required for recording of weight and CoG data;
b) verify the calculated weight and CoG of assemblies, modules or topsides by means of physical
weighings;
c) have less stringent requirements for updating “as-built” status during fabrication.
8 © ISO 2016 – All rights reserved

ISO 19901-5:2016(E)
5.4  Class C: Low definition of weight and CoG
Class C shall apply to projects where requirements for updating “as-built” status during fabrication is
not critical.
Class C weight projects shall:
a) as a minimum use a spread sheet software for recording weight and CoG data;
b) verify the calculated weight and CoG of assemblies, modules or topsides by means of physical
weighings;
c) provide supporting weight and CoG documentation consisting of equipment weights and
summarized bulk weights by drawing;
d) have no requirements for updating “as-built” status during fabrication.
5.5 Selection of class of weight control
The design b
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