EN ISO 19901-5:2003

SLOVENSKI STANDARD
01-maj-2004
Petroleum and natural gas industries - Specific requirements for offshore
structures - Part 5: Weight control during engineering and construction (ISO 19901
-5:2003)
Petroleum and natural gas industries - Specific requirements for offshore structures -
Part 5: Weight control during engineering and construction (ISO 19901-5:2003)
Erdöl- und Erdgasindustrie - Offshore-Plattformen - Teil 5: Gewichtskontrolle während
der Auslegung und Konstruktion (ISO 19901-5:2003)
Industries du pétrole et du gaz naturel - Exigences spécifiques relatives aux structures
en mer - Partie 5: Contrôles des poids durant la conception et la fabrication (ISO 19901-
5:2003)
Ta slovenski standard je istoveten z: EN ISO 19901-5:2003
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.

EUROPEAN STANDARD
EN ISO 19901-5
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2003
ICS 75.180.10
English version
Petroleum and natural gas industries - Specific requirements for
offshore structures - Part 5: Weight control during engineering
and construction (ISO 19901-5:2003)
Industries du pétrole et du gaz naturel - Exigences Erdöl- und Erdgasindustrie Besondere Anforderungen an
spécifiques relatives aux structures en mer - Partie 5: Offshore- Bauwerke - Teil 5: Gewichtskontrolle während der
Contrôles des poids durant la conception et la fabrication Auslegung und Konstruktion (ISO 19901-5:2003)
(ISO 19901-5:2003)
This European Standard was approved by CEN on 10 July 2003.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 19901-5:2003 E
worldwide for CEN national Members.

Foreword
This document (EN ISO 19901-5:2003) has been prepared by Technical Committee ISO/TC 67
"Materials, equipment and offshore structures for petroleum and natural gas industries" in
collaboration with Technical Committee CEN/TC 12 "Materials, equipment and offshore
structures for petroleum and natural gas industries", the secretariat of which is held by AFNOR.
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 January 2004, and conflicting national
standards shall be withdrawn at the latest by January 2004.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium, Czech
Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and
the United Kingdom.
NOTE FROM CMC  The foreword is susceptible to be amended on reception of the German
language version. The confirmed or amended foreword, and when appropriate, the normative
annex ZA for the references to international publications with their relevant European
publications will be circulated with the German version.
Endorsement notice
The text of ISO 19901-5:2003 has been approved by CEN as EN ISO 19901-5:2003 without any
modifications.
INTERNATIONAL ISO
STANDARD 19901-5
First edition
2003-07-15
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: Contrôles des poids durant la conception et la fabrication

Reference number
ISO 19901-5:2003(E)
©
ISO 2003
ISO 19901-5:2003(E)
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ii © ISO 2003 — All rights reserved

ISO 19901-5:2003(E)
Contents Page
Foreword. v
Introduction . vii
1 Scope. 1
2 Normative references. 2
3 Terms, definitions and abbreviated terms. 2
3.1 Terms and definitions. 2
3.2 Abbreviated terms. 7
4 Weight control classes. 7
4.1 General. 7
4.2 Class A: High definition of weight and CoG requirements. 7
4.3 Class B: Medium definition of weight and CoG requirements. 8
4.4 Class C: Low definition of weight and CoG requirements . 8
4.5 Selection of weight control class . 8
5 Weight and load budget (WLB). 9
5.1 General. 9
5.2 Requirements. 10
5.3 Weight and load budget (WLB) content. 10
5.3.1 General. 10
5.3.2 50/50 weight estimate . 11
5.3.3 Weight reserves. 12
5.3.4 Future weights and loads. 12
5.3.5 Loading conditions and parameters . 13
5.3.6 Weight and load budget (WLB) formats and levels. 14
5.3.7 CoG constraints. 15
6 Weight reporting. 15
6.1 General. 15
6.2 The weight control procedure . 16
6.3 Requirements to the weight report . 17
6.3.1 Introduction to the report. 17
6.3.2 Summary and conclusions to the report. 17
6.3.3 Area/module reports. 19
6.3.4 Special reports (optional). 20
6.3.5 Annexes to the report. 21
7 Requirements for weight data from suppliers and weighing of bulk and equipment. 22
7.1 General. 22
7.2 Provision of weight information . 22
7.3 Requirements for weighing. 23
7.4 Weighing equipment. 23
7.5 Weighing procedure. 23
7.6 Notification and witnessing of weighing . 24
7.7 Calibration of weighing equipment . 24
7.8 Weighing operation. 24
7.9 Temporaries during weighing. 25
7.10 Items excluded during weighing . 25
8 Requirements for weighing of major assemblies. 25
8.1 Weighing procedure. 25
8.2 Environmental conditions. 25
8.2.1 Light. 25
ISO 19901-5:2003(E)
8.2.2 Wind.26
8.2.3 Temperature and humidity .26
8.3 Weighing.27
8.3.1 Number and timing of weighings.27
8.3.2 Weighing procedure.27
8.3.3 Notification and witnessing of weighings .28
8.3.4 Preparation of the weighing.28
8.3.5 Weighing equipment.29
8.3.6 Calibration of weighing system .31
8.3.7 Foundation and supports .32
8.3.8 Structural integrity.32
8.3.9 Weighing operation.32
8.3.10 CoG calculations.33
8.3.11 Weighing certificate.34
8.3.12 Weighing report.34
9 Requirements for “as-built” weight documentation.35
Annex A (informative) Weight data sheets — Tagged equipment .36
Annex B (informative) Weighing certificates .38
Annex C (informative) Weight and load budget (WLB) formats and levels .42
Annex D (informative) Major elements of the weight displacement .43
Annex E (informative) Supplier weighing procedure .44
Annex F (informative) Guidelines for displacement measurement of floaters.46
Bibliography.50

iv © ISO 2003 — All rights reserved

ISO 19901-5:2003(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 19901-5 was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore structures
for petroleum, petrochemical and natural gas industries, Subcommittee SC 7, Offshore structures.
ISO 19901 consists of the following parts, under the general title Petroleum and natural gas industries —
Specific requirements for offshore structures:
 Part 4: Geotechnical and foundation design considerations
 Part 5: Weight control during engineering and construction
The following parts of ISO 19901 are under preparation:
 Part 1: Metocean design and operating considerations
 Part 2: Seismic design procedures and criteria
 Part 3: Topsides structure
 Part 6: Marine operations
 Part 7: Stationkeeping systems for floating offshore structures and mobile offshore units
ISO 19901 is part of a series of standards for offshore structures. The full series consists of the following
standards:
 ISO 19900, Petroleum and natural gas industries — General requirements for offshore structures
 ISO 19901 (all parts), Petroleum and natural gas industries — Specific requirements for offshore
structures
 ISO 19902, Petroleum and natural gas industries — Fixed steel offshore structures
 ISO 19903, Petroleum and natural gas industries — Fixed concrete offshore structures
 ISO 19904, Petroleum and natural gas industries — Floating offshore structures
ISO 19901-5:2003(E)
 ISO 19905-1, Petroleum and natural gas industries — Site-specific assessment of mobile offshore
units — Part 1: Jack-ups
 ISO/TR 19905-2, Petroleum and natural gas industries — Site-specific assessment of mobile offshore
units — Part 2: Jack-ups commentary
 ISO 19906, Petroleum and natural gas industries — Arctic offshore structures
vi © ISO 2003 — All rights reserved

ISO 19901-5:2003(E)
Introduction
The offshore structures International Standards ISO 19900 to ISO 19906 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.
The offshore structures International Standards 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.
INTERNATIONAL STANDARD ISO 19901-5:2003(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 and materials.
This part of ISO 19901 differentiates between projects where considerations with regard to weight and CoG
have a high priority as a result of weight and/or CoG sensitivity, and projects where weight and CoG are of
little consequence. This differentiation has been made by the introduction of three different classes of
structure (Class A, Class B and Class C). Depending on the degree of control necessary, different clauses of
this part of ISO 19901 will apply; Clause 4 provides guidelines for assigning one of these classes.
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 status reports or management reports for all classes,
 specifies requirements for weight and load budgets for offshore installations,
 specifies the methods and requirements for the weighing of major assemblies, and the determination of
weight and centre of gravity,
 specifies requirements for weight information from suppliers, including weighing of equipment and bulk
materials for offshore installations;
and may be used
 as a basis for planning and presentation of the contractor's weight-reporting system;
 as a basis for evaluation of the contractor's weight-reporting system;
 as a means of refining the structural analysis/model;
 as a contract reference between the ordering client and the contractor;
 as a basis for costing.
ISO 19901-5:2003(E)
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.
Guide to the expression of uncertainty in measurement (GUM), BIPM, IEC, IFCC, ISO, IUPAC, IUPAP and
OIML
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
assembly
designed and fabricated group of bulk and equipment items which form one unit
3.1.2
ballast
variable solid or fluid content used to trim a floating structure and/or keep a certain draft
3.1.3
base weight estimate
weight estimate used for budgeting purposes which does not include any unforeseen quantity growth,
estimating errors or unnamed events
3.1.4
base weight contingency
weight addition, based on risk analysis or experience, used to transform a base weight estimate into a 50/50
weight estimate accounting for uncertainties
3.1.5
budget weight
weight reference figures as defined in the weight and load budget and related to the initial or changed design
concept
3.1.6
bulk
component or arrangement of components defined as stock materials or of low complexity
NOTE Bulk items support the equipment items by providing infrastructure around and between them.
3.1.7
client weight reserve
weight addition with CoG (usually a fixed weight) controlled by the client and used to cater for any orders for
variation to the contractual design concept
3.1.8
CoG envelope
defined constraint volume within which the CoG of an assembly must remain for design purposes
3.1.9
consumables
variable content, which is solid in stores and fluid in utility tanks
EXAMPLES Fuel, provisions, service/potable water, operating utilities.
2 © ISO 2003 — All rights reserved

ISO 19901-5:2003(E)
3.1.10
contractor weight reserve
weight addition (usually a fixed weight) controlled by the contractor and used to cater for any design growth
due to development of the initial design concept
3.1.11
deadweight
total carrying capacity of a floating structure
NOTE Includes weight of crude oil, deck cargo, temporaries, water, snow and ice accumulations, marine growth,
ballast water, consumables, crew and their effects.
3.1.12
displacement
weight of the volume of water displaced by a floating structure, which is the sum of lightweight and deadweight
3.1.13
dry weight
weight of a component, weight item or an assembly in its dry installed condition including permanent utilities
NOTE 1 Examples of permanent utilities are gearbox oil, hydraulic oil, filter sand, etc.
NOTE 2 Any content of operating fluid flowing through a component, weight item or an assembly is excluded.
3.1.14
equipment
component, or arrangement of components, built for specific function(s)
NOTE The component/assembly normally has unique documentation due to its function and complexity.
3.1.15
first fill
initial filling of liquid in equipment items, piping lines or tanks
NOTE First fill typically takes place towards the end of site construction, prior to tow-out and prior to filling for normal
operations.
3.1.16
float-out
loading condition in which a major assembly is transferred from a dry construction site to become self-floating
3.1.17
fluid content
all fluids flowing through a component, weight item or an assembly
EXAMPLES Process gases, liquids, powders, etc.
3.1.18
future weight
weight of a component or an assembly to be installed after the start of production
NOTE Start of production is also known as “first oil”.
3.1.19
grillage
temporary structural foundation assemblies for modules or sections during transportation
3.1.20
gross reported weight
sum of the net weight and weight allowance
ISO 19901-5:2003(E)
3.1.21
gross WTO
gross weight take-off
sum of the net WTO and weight allowance
3.1.22
gross weight/WTO contingency
difference between the gross reported weight and the gross WTO at any time during the project execution
3.1.23
hook-up
installation and commissioning of components or assemblies after the modules have been installed in their
final position
3.1.24
hook weight
sum of lift weight and lifting gear weight
3.1.25
lifting gear
rigging
equipment needed during a lifting operation
EXAMPLES Slings, spreader bars, lifting frames, shackles, etc.
3.1.26
lift weight
weight of a component, an assembly or a module at padeyes, including temporaries and residual fluid content
but excluding lifting gear
3.1.27
lightweight
lightship
dry weight and utility systems required for a minimum operation of a floating structure
3.1.28
live load
load on a deck area according to its defined function
3.1.29
loading condition
defined event or operation during which loads occur
NOTE For each loading condition, all weight items and variable loads that are known or predicted to occur are
identified, quantified and located.
3.1.30
load-out
loading condition in which a major assembly or a module is transferred from land onto a floating structure by
horizontal movement
3.1.31
mating
loading condition in which a major assembly supported on vessel(s) is joined onto its temporary or permanent
substructure
4 © ISO 2003 — All rights reserved

ISO 19901-5:2003(E)
3.1.32
net weight
weight (excluding any allowances or contingencies) obtained either by estimation as estimated from early
design documents or present sketches, calculated take-off from drawings or 3D model, or as given in vendor
data-sheets or obtained by physical weighing
3.1.33
net WTO
net weight take-off
weight derived from calculated take-off or from 3D model, given in vendor data-sheets or weighed, excluding
any allowances or contingencies
3.1.34
not-to-exceed weight
NTE weight
maximum acceptable weight
3.1.35
operating weight
sum of the dry weight and the fluid content weight
3.1.36
project management
dedicated management personnel with the task of implementing weight policy, objectives and procedures
3.1.37
residual fluid content
fluid content remaining after testing or commissioning and present during the subsequent loading condition
until the start of production
3.1.38
sea fastening
items used for temporary fastening to keep movable items in position during transportation at sea
3.1.39
tagged equipment
equipment tagged in accordance with the project coding manual
3.1.40
temporaries, noun pl
components, assemblies or utility items which are temporarily installed during a specific loading condition and
removed afterwards, either prior to or after installation
3.1.41
test weight
sum of the dry weight plus the fluid content required to test the equipment and assembly
3.1.42
tow-out
final towing of a complete floating structure to the offshore production field
3.1.43
transport
loading condition in which a major assembly or a module is transferred from one inshore/at shore location to
another location or to the offshore production field
ISO 19901-5:2003(E)
3.1.44
weight allowance
quantified weight addition accounting for definable components which could not be specified at the actual
project stage
NOTE Weight allowance is expressed either as a percentage or as a lump sum.
3.1.45
weight contingency
weight addition, based on risk analysis or experience, used to transform a base weight estimate to a 50/50
weight estimate accounting for uncertainties and/or definable components which could not be specified at the
actual project stage
NOTE Weight contingency is expressed either as a percentage or as a lump sum.
3.1.46
weight item
defined collection of bulk and/or equipment, design volume or assembly suitable for weight reporting purposes
3.1.47
weight installation code
computer code which verifies whether a component or a weight item is physically installed or not in an
assembly or module
3.1.48
weight management
all planned and controlled activities which deal with the
 definition and publication of the project weight objective and policy,
 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.
NOTE The project management, the engineering disciplines and the weight control discipline are actively cooperating
and taking part in and influencing the weight management process by means of adequate working methods and tools, to
include weight optimization, weight consciousness and weight reductions.
3.1.49
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
3.1.50
weight phase code
computer code defining in which loading conditions a component or a weight item is present
3.1.51
weight policy
statement by the project management based on the weight objective and how it will be achieved
NOTE The statement should as a minimum describe
 the weight objective's importance to the project aims and results,
 the priority, profile and control at different levels in the project,
 a philosophy for responsibility and authority within and between project groups engaged in weight/CoG matters.
6 © ISO 2003 — All rights reserved

ISO 19901-5:2003(E)
3.1.52
weight reporting
adequate and timely weight/CoG information reported with respect to content and presentation in order to fulfil
expectations and requirements from/needs of organizations involved in the project
3.1.53
weight status code
computer code related to the weight item level of accuracy
3.1.54
50/50 weight estimate
value representing the median value in the probability distribution of weight estimates
NOTE The actual weight value is equally likely to be smaller or larger than the 50/50 weight estimate.
NOTE The 50/50 weight estimate is used as the basis for weight budgeting.
3.2 Abbreviated terms
CoG centre of gravity
LCG longitudinal centre of gravity
MEL master equipment list
NTE not to exceed
TCG transverse centre of gravity
TLP tension leg platform
WLB weight and load budget
WTO weight take-off
4 Weight control classes
4.1 General
In order to select the most appropriate level for weight control and weight reporting according to the degree of
weight and/or CoG sensitivity of the project, three classes of weight control have been defined.
The tender documents and final contract shall specify the applicable weight control class, so that the
contractor can allocate the required resources.
4.2 Class A: High definition of weight and CoG requirements
Class A shall apply if the project is weight- or CoG-sensitive for lifting and marine operations or during
operation (with the addition of temporaries), or has many contractors with which to interface. Projects may
also require this high definition if risk gives cause for concern.
Full traceability of weights shall be given for this class, commencing with all documented weight data from
suppliers.
Recording of weight data for Class A requires the use of a relational-type database from the commencement
of detail engineering, with suppliers' data, fabricators' data and data from physical weighings integrated into
the system.
ISO 19901-5:2003(E)
The theoretical weight and CoG of assemblies shall be verified by means of physical weighings. Three
weighings are recommended and, as a minimum requirement, two weighings for each major assembly shall
be carried out.
The weight data, at piecemark level, produced in the design phases in the form of weight dossiers (if
applicable), shall be updated to “as-built” status during the fabrication stage.
4.3 Class B: Medium definition of weight and CoG requirements
Class B shall apply to projects where the focus on weight and CoG is less critical for lifting and marine
operations than for projects where Class A is applicable. The requirements for the “as-built” status are relaxed
and the number of physical weighings may be reduced.
The complexity of the project shall determine whether a relational-type database is necessary for recording of
the weight data, or whether spreadsheet software can be used.
4.4 Class C: Low definition of weight and CoG requirements
Class C shall apply to projects where the requirements for weight and CoG data are not critical.
A final weighing should be performed which would constitute the “as-built” weight.
Supporting documentation consisting of equipment weights and summarized discipline weights by drawing
shall be provided.
Spreadsheet software can be used.
4.5 Selection of weight control class
The design basis, NTE weight and CoG criteria, together with WLBs established at the close of the concept
phase, are major factors to be considered when selecting the weight control class.
Potential weight and CoG problems whether for load-out, transportation, mating, inshore lift, float-out, tow-out,
offshore lift or operating phase, also need to be assessed before selecting the weight control class. Even a
module or structure significantly under projected weight could lead to a serious problem if not diagnosed
before marine operations.
Class selection may be made from examination of Table 1, which is included as a guide for determining the
required degree of weight and CoG control needed for a project.
Table 1 — Guidance criteria for weight control class selection
Description Class A Class B Class C
Concept type new partly known well known
Weight sensitivity high medium low
CoG sensitivity high medium low
Weight data processing high medium low
requirement
Contract requirement detailed general none
Weight data external interfaces 4 to 6 1 to 3
> 6
(other contractors)
8 © ISO 2003 — All rights reserved

ISO 19901-5:2003(E)
5 Weight and load budget (WLB)
5.1 General
Class A Class B Class C
For all offshore installations, the total As Class A. As Class A, except that d) is not
weight and load situations shall be required.
controlled from the conceptual beginning.
Budget weights including CoG constraints
shall be worked out for the topsides,
substructure and individual modules
including temporaries (as appropriate)
corresponding to the appropriate loading
conditions, in cooperation with the
structural and marine disciplines in
addition to the management, and
presented in WLBs as a comparison
reference during an engineering and
construction project.
The main purposes of the WLBs 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 sub-structure;
c) bearing capacity and stability of the
total structure (temporary or
permanent);
d) overall cost and schedule control.

ISO 19901-5:2003(E)
5.2 Requirements
Class A Class B Class C
Each participant in a project shall be As Class A. The contractor WLBs are established
allocated a separate WLB. Typically either by the client, and are included
WLB's for the client, the contractor and the in the project contract, or by the
sub-contractors are allocated. project contractor. Unless specified
by the client, the format and
The contractor WLBs shall be established
complexity is left to the discretion of
either by the client, in which case they
the contractor.
shall be included in the project contract, or
by the project contractor.
The project management/client shall hold
overall responsibility for deciding the
variations between the various WLBs.
WLBs for subcontractors and vendors
shall be established by the contractor.
No revisions to WLBs shall take place
under normal circumstances unless
concept or major design changes to the
design which impact on the weight, load or
CoG, are implemented by the project
management/client.
All participants in the project shall be
responsible for adherence to actual weight
and CoG WLB figures.
In the event that the project weight control
and weight reporting detects the possibility
of significant variations from the WLBs,
corrective actions shall be initiated by the
project management and the design
disciplines and closely followed up in
order that overruns do not occur or
implications are minimized.
5.3 Weight and load budget (WLB) content
5.3.1 General
Class A Class B Class C
The WLB consists of different types of As Class A. As Class A.
weights, loads and associated CoGs, see
Figure 1.
10 © ISO 2003 — All rights reserved

ISO 19901-5:2003(E)
Key
1 weight 8 not to exceed weight
2 base weight contingency 9 50/50 weight estimate
3 base weight estimate 10 time
4 contract award 11 as-built
5 gross weight contingency 12 weight allowance
6 future 13 gross WTO
7 reserves 14 net WTO
Figure 1 — General weight development figure
5.3.2 50/50 weight estimate
Class A Class B Class C
The primary basis for the WLB figures are As Class A. As Class A.
the weight, load and CoG estimates for
the chosen design concept, carried out
either by the client or the contractor.
If it is found necessary, the basis for the
WLBs may be verified by re-estimation at
the commencement of the engineering
phase.
Normally, the weight allowance and base
weight contingency are included as a part
of the estimated weight to determine the
50/50 weight estimate of the facility.

ISO 19901-5:2003(E)
5.3.3 Weight reserves
Class A Class B Class C
A contractor weight reserve may be added As Class A. As Class A.
on top of the WLB 50/50 weights.
The design maturity and the project policy
established by the project management
with respect to design control and
maximum tolerable design development
have an influence on the weight reserve
figure.
In addition to the contractor weight
reserve, the client may add its own client
weight reserve.
Any relevant variation orders issued by
the client after the contract issue can
affect the reserve figure and normally
necessitate a WLB revision.
In special situations, if the chosen design
concept is declared too heavy and thus
subject to weight reductions, the weight
reserve will be negative. This might create
a WLB weight below the current estimated
or reported weight.
5.3.4 Future weights and loads
Class A Class B Class C
Future weights and/or loads are not As Class A. As Class A.
included in the weight reserve, but shall
be identified separately in the WLBs.

12 © ISO 2003 — All rights reserved

ISO 19901-5:2003(E)
5.3.5 Loading conditions and parameters
5.3.5.1 General
Class A Class B Class C
A set of relevant loading conditions and As Class A. As Class A.
associated weight/load parameters shall
be defined for weight control and weight
reporting purposes during the fabrication,
installation and operating phases of the
project.
Corresponding WLBs shall be worked out Not required.
for the actual loading conditions in
cooperation with the structural and marine
disciplines especially, in addition to the
management.
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