ISO 15686-7:2006

Buildings and constructed assets - Service life planning - Part 7: Performance evaluation for feedback of service life data from practice

ISO 15686-7:2006 provides a generic basis for performance evaluation for feedback of service life data from existing buildings and constructed assets, including a definition of the terms to be used and the description of how the (technical) performance can be described and documented to ensure consistencies.

Bâtiments et biens immobiliers construits — Prévision de la durée de vie — Partie 7: Évaluation de la performance de l'information en retour relative à la durée de vie, issue de la pratique

General Information

• Status: Withdrawn
• Publication Date: 27-Feb-2006
• Withdrawal Date: 27-Feb-2006
• ICS: 91.040.01 - Buildings in general
• Technical Committee: ISO/TC 59/SC 14 - Design life
• Drafting Committee: ISO/TC 59/SC 14 - Design life
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 24-Apr-2017
• Completion Date: 13-Dec-2025

Relations

• Revised: ISO 15686-7:2017 - Buildings and constructed assets - Service life planning - Part 7: Performance evaluation for feedback of service life data from practice
• Effective Date: 17-Dec-2011

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 15686-7
First edition
2006-03-01
Buildings and constructed assets —
Service life planning —
Part 7:
Performance evaluation for feedback of
service life data from practice
Bâtiments et biens immobiliers construits — Prévision de la durée de
vie —
Partie 7: Évaluation de la performance de l'information en retour relative
à la durée de vie, issue de la pratique

Reference number
©
ISO 2006
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ii © ISO 2006 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Methodological framework . 3
5 Performance surveys . 5
Annex A (informative) Guidance on Factor E — Environmental classification systems and
methods for assessment in microenvironment. 16
Annex B (informative) Prediction of (residual) service life on the object (single building) level and
on the network level (population of buildings). 21
Annex C (informative) Worked example of RSL data records from “Inspection of buildings”. 23
Bibliography . 26

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 15686-7 was prepared by Technical Committee ISO/TC 59, Building construction, Subcommittee SC 14,
Design life.
ISO 15686 consists of the following parts, under the general title Buildings and constructed assets — Service
life planning:
⎯ Part 1: General principles
⎯ Part 2: Service life prediction procedures
⎯ Part 3: Performance audits and reviews
⎯ Part 5: Whole life costing
⎯ Part 6: Procedures for considering environmental impacts
⎯ Part 7: Performance evaluation for feedback of service life data from practice
⎯ Part 8: Reference service life
iv © ISO 2006 – All rights reserved

Introduction
ISO 15686, with the general title Buildings and constructed assets — Service life planning, of which this
document is Part 7, is an important contribution to the development of a policy for design life. A major impetus
for the preparation of the parts of ISO 15686 is the current concern over the inability to predict service life,
costs of ownership and maintenance of buildings and constructed assets. Common methods and standards
for performance assessment and proper feedback of data from practice are decisive in order to make
experience data from the building stock consistent and comparable. The purpose of this part of ISO 15686 is
therefore to describe the principles for service life performance surveys and evaluation with an emphasis on
technical recommendations. It aims to describe a generic methodology, including the terms to be used, that
provide guidance on the planning, documentation and inspection phases, as well as on analysis and
interpretation of performance evaluations, both on the object (single building) and network (stock of buildings)
level. Maintenance planning is outside the scope of this part of ISO 15686.
ISO 15686-7 is intended for all members of a building team, i.e. building owners and developers, professional
advisors, constructors, assessors, manufacturers of building products, managers of both publicly and privately
owned constructed assets.
INTERNATIONAL STANDARD ISO 15686-7:2006(E)

Buildings and constructed assets — Service life planning —
Part 7:
Performance evaluation for feedback of service life data from
practice
1 Scope
This part of ISO 15686 provides a generic basis for performance evaluation for feedback of service life data
from existing buildings and constructed assets, including a definition of the terms to be used and the
description of how the (technical) performance can be described and documented to ensure consistencies.
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 6241:1984, Performance standards in building — Principles for their preparation and factors to be
considered
ISO 15686-1:2000, Buildings and constructed assets — Service life planning — Part 1: General principles
ISO 15686-2:2001, Buildings and constructed assets — Service life planning — Part 2: Service life prediction
procedures
1)
ISO 15686-8:— , Buildings and constructed assets — Service life planning — Part 8: Reference service life
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 15686-1, ISO 15686-2 and the
following apply.
3.1
consequence degree
expression of the seriousness of consequences in relation to a defined reference level
3.2
network level
stock of objects (facilities, e.g. bridges, tunnels, power plants, buildings) under management and maintenance
of an owner
1) In preparation.
3.3
object level
basic unit of the network serving a specific function
3.4
performance survey
total survey (defining of the task, planning, examination, evaluation and reporting) at a given time in
accordance with this part of ISO 15686
3.5
performance assessment
all material that accounts for an item’s performance throughout its service life
3.6
performance degree
expression of the performance of an item in relation to a defined reference level
3.7
performance control
comparison between performance and defined requirements
3.8
refurbishment
modification and improvements to an existing item to bring it up to an acceptable condition
[ISO 6707-1]
3.9
repair
return a product/component/assembly/system to an acceptable condition by renewal, replacement or mending
of worn, damaged or degraded parts
[ISO 6707-1]
3.10
renewal
demolition and rebuilding of an existing item
3.11
replacement
change of parts of an existing item to regain its functionality
3.12
risk
probability of an event (e.g. failure, damage) multiplied by its consequences (e.g. cost, fatalities, exposure to
personal or environmental hazard)
3.13
symptom
indicator of the loss of performance of an item
3.14
in-use condition
any circumstance that contributes to or causes the degradation of a building/constructed assets or a part of it
under normal use
NOTE In order to encompass all of the seven factor classes of the Factor method, this definition has been extended
relative to that given in ISO 15686-2:2001, 3.3.5, thus being in accordance with ISO 15686-1:2000, 3.1.2, where “in-use
condition” is referred to as influencing any of the seven factors.
2 © ISO 2006 – All rights reserved

3.15
usage conditions
in-use conditions due to users of a building/constructed assets, and human activity adjacent to a
building/constructed assets
NOTE In this part of ISO 15686, the Factor class F is designated “usage conditions” rather than “in-use condition” as
used but not defined in ISO 15686-1. This is called for in order to distinguish the factor class from the term “in-use
condition” as defined in ISO 15686-2 as “environmental condition under normal use”.
3.16
factor class
label of an in-use condition indicating which factor of the Factor method the condition will influence
3.17
in-use condition grading
act of collective judgement of all qualitative information of in-use conditions within a factor class
3.18
in-use condition grade
outcome of an in-use condition grading
4 Methodological framework
4.1 Service life planning
In ISO 15686-1, the concept of reference service life (RSL) is defined as the “service life of a
product/component/assembly/system that is known to be expected under a particular set, i.e a reference set,
of in-use conditions and which may form the basis of estimating the service life under other in-use conditions”.
A person working with the service life planning (SLP) of a design object is faced with the problem of
forecasting the service life of its components. Even if there are certain service life data available, i.e. RSLs,
these can rarely be used directly. This is because the project-specific in-use conditions, to which the object’s
components are subjected, are usually different from those under which the service life data are valid, i.e. the
reference in-use conditions.
In ISO 15686-1:2000, Clause 9, the Factor method is described as a means to overcome this problem. The
Factor method is used to modify an RSL to obtain an estimated service life (ESL) of the components of a
design object, while considering the difference between the project-specific and the reference in-use
conditions. This is carried out by multiplying the RSL by a number of factors, each of which reflect the
difference between the two sets of in-use conditions within a particular factor class:
ESL = RSL × Factor A × Factor B × Factor C × Factor D × Factor E × Factor F × Factor G
The factor classes are given in Table 1.
NOTE The Factor method will be moved to ISO 15686-8 when ISO 15686-1:2000 is revised.
Table 1 — Factor classes of the Factor method
Factor classes of the Factor method
Factor class Designation
A quality of components
B design level
C work execution level
D indoor environment
E outdoor environment
F usage conditions
G maintenance level
The evaluation of an ESL according to the Factor method requires the input of an RSL as well as the numbers
of the Factor classes A to G. A proper choice of the numbers of the factors depends on the difference
between the project-specific and the reference in-use conditions. Therefore, in order to enable estimations of
the Factor classes A to G jointly with RSL, the reference in-use conditions in terms of the factor classes
should, as far as possible, be included when providing data.
Currently, there are a limited number of systematic studies on service life prediction and there is an urgent
need for data. For the provision of RSL data, the capturing of existing data of any kind is acceptable.
4.2 Performance assessment of service life in the course of the construction life cycle
4.2.1 Relation to service life design and reference service life (RSL)
The performance levels of the construction and its components change during the life cycle of the construction
(see Figure 1). The in-use conditions can also be subject to change. Therefore, a proper assessment of the
service life during the construction life cycle should include a thorough assessment of the existing in-use
conditions, and record any changes to the levels used in the design process, if applicable.
A main objective of this part of ISO 15686 is to provide a basis for objective assessment and to describe how
information retrieved during performance assessments can become new input in the RSL data, as described
in ISO 15686-8. As such, this part of ISO 15686 adds further to the data generating method of inspection of
the building specified in ISO 15686-1:2000, 8.2.5 b).
4.2.2 Life cycle performance of construction
Figure 1 illustrates scenarios in the development of the performance (bold line) of construction works from
delivery through the maintenance and operation phase. There is a deviation (gap) in performance from the
client’s expectations and requirements from the brief (initial) phase until the delivery (“as built”) phase, often
due to failures or damage during fabrication. The expectation gap is increased further due to the continuous
rise in new requirements and upgrading, business development, etc.
After the delivery, performance decreases during operation, due to wear and tear, or simply the age factor, if
left with no maintenance. Therefore, the construction and its components are subjected to various corrective
actions, or maintenance, in order to keep up with required performance. These actions can be proactive,
which is preferred, or reactive, which is largely the current practice. In both cases, inspections and
performance assessments should be the basis for maintenance planning. This applies to all functionalities.
This part of ISO 15686 defines a generic protocol and terms for how to evaluate the service life performance
during this life cycle. Maintenance planning is outside the scope of this part of ISO 15686, but for the sake of
illustration, Figure 1 relates the assessed performance levels to various known maintenance actions, as
defined in ISO 15686-1. The content of, and relations between, such levels and actions should be defined by
users separately.
4 © ISO 2006 – All rights reserved

Key
Y quality/function 5 preventative and periodic maintenance
X operation and management of building over time 6 limit states
1 expectation/achievement gap 7 refurbishment
2 building failure/damage 8 repair
3 new requirements — public 9 replacement
— market
10 performance without preventative actions
— business
11 renewal
4 development upgrading 12 “as built”
a
Performance degrees (PD) are defined in 5.3.4.2.2.
Figure 1 — Life cycle performance of construction
5 Performance surveys
5.1 General
The main purpose of this part of ISO 15686 is to be an aid in the planning and preparation of required general
and specific working documents for the performance survey of items of various character and different
purpose. General and specific working documents supplementary to carrying out performance surveys can be
described in three levels, as given in Table 2.
Table 2 — Overview of document levels
Document Main function Content
This part of Provides a standardized framework Definitions, method and content
ISO 15686 for planning and for terms and
methods
General working Provides agreed (objective) fixed Specific symptom lists and/or illustrated catalogues, for
documents for terms (reference level) for the example:
performance performance of a building product or
—  concrete;
surveys construction method
—  masonry;
—  external wood;
—  steel;
—  ventilation ducts.
Checklists for likely locations of failure prepared on the
basis of this part of ISO 15686
Specific working Provides specific directions on how a Complete work guidance for the performance survey of a
documents for type of item should be handled. type of item, for example:
performance
Should also provide the reference —  bridges;
surveys
level for performance degrees for the —  old town buildings;
relevant type of item —  stave churches;
—  ventilation systems.
These should be prepared by those who request the
survey for a type of item (facility manager, property owner,
etc.) on the basis of the standard and general working
documents
This part of ISO 15686 can be used
a) directly as an aid for performance surveys when no other working documents exist, or as a supplement
when the working documents are incomplete;
b) to prepare general working documents;
c) to prepare specific working documents.
5.2 Registration level and user-oriented types of inspection
There are three levels of registration as follows:
a) level 1 (preliminary): Performance registration of a general character consisting of visual observations
combined, if necessary, with simple measurements.
b) level 2 (regular): Performance registration of a general character, but more exhaustive and detailed than
Level 1. It includes examination of supporting data, e.g. drawings, specifications and other documentation.
More extensive registrations or measurements should be carried out to establish the construction and
performance of the item when required.
c) level 3 (detailed): Performance registration of a special character that includes only specific items
(building elements, construction elements, work sections) or specific problems. Such performance
registration implies the application of especially accurate measurement or test methods and, if
appropriate, laboratory testing.
Types of inspection should be designed from these various levels of registration according to user needs and
required competence of inspectors, as given in Table 3.
6 © ISO 2006 – All rights reserved

Table 3 — Types of inspection and competence level required of inspectors
Type of
Purpose Minimal inspector qualification
inspection
Preliminary Introductory inspection of a general character consisting Has a technical education, knows the
of visual observations and basic measurements to get a building and is able to identify the
very rough overview concerned parts and critical phenomena
Regular Inspection at regular intervals, such as Architect, civil engineer, facility
manager, craftsmen, technician
—  every 1 to 2 years, for analysis of weak points or
failures in the construction;
—  every 3 to 10 years, for
—  design and preparation of tenders in restoration
and rehabilitation project,
—  defining the inspection plan, programming the
object-individual questions for inspection,
—  planning of renovation, control of adequate use,
cost estimates for maintenance measures
Specific/detailed Special tasks, such as
Proofed/certified specialist in the
(ordered from the relevant field, e.g. scientist, laboratory
—  detailed specification of the extent of any damage
levels above) engineer, software engineer
—  difficult and/or unusual situations
—  research work
5.3 Phases and activities in the performance survey
5.3.1 General overview
A performance survey should consist of the following main phases:
a) defining the task;
b) planning;
c) examination;
d) evaluation;
e) reporting.
NOTE A more detailed analysis of this process is given in Table 4.
Performance surveys should be carried out by personnel having the relevant technical background within the
field being surveyed (see Table 3). All fields that are relevant to the purpose of the performance survey should
be covered.
5.3.2 Defining the task
5.3.2.1 General
The purpose, extent and resources required for the performance survey should be established, described and
documented.
5.3.2.2 Purpose
A prerequisite of the performance survey is to define the purpose of the survey, i.e. to clarify what the survey
should be used for. For example, the purpose of performance surveys in relation to construction works or
construction works elements can be to:
a) provide performance documentation and RSL data for manufacturer’s product documentation;
b) form the basis for maintenance plans;
c) determine (in the case of urban city renewal) whether a construction works should be demolished or
renovated;
d) inspect for completion and for notification of defects;
e) assist with purchase and sale;
f) assist in undertaking valuation (technical part);
g) assist in preparing conservation documentation.
Table 4 — Phases and activities in the performance assessment protocol
Main phase Activity/content Examples/elaboration
Defining the task Purpose Planning of maintenance, repair and renovation. Evaluation of damage and
Residual Service Life. Valuation. Conservation documentation
Extent/level Item: field, building, construction work, elements. Evaluate, define the
registration level. Sampling. Cost calculation of action
Cost of analysis Own cost and purchased services
Planning Basic material Drawings, specifications, performance documentation
Registration scheme Systematic, orientation system, statistical selection, aids
Plan Examination, inspection, meetings information, access
Recording of age, Examination Symptoms, in-use conditions
in-use conditions
Performance degree Description of performance via pictures and measurements
and performance
levels
Documentation Photographs
Evaluation In-use conditions Critical properties and performance requirements/prediction of service life
Performance control Requirements set by authorities, regulations. Requirements set by the
client/user requirements
Failure Definition from reference level, insufficient documentation
Probabilities and Reconsider the extent of the registration, failure distributions and
consequences consequence degrees
Risk Evaluated and used as a basis for action profiles
Actions Recommendations, priorities/costs if appropriate
Reporting Introduction Purpose. Identification of the item, main structure, construction age, extend
of level, time of survey, client and contractor, other parties involved.
Conclusion Main conclusion, summary, performance, recommended actions, costs,
economy, recommendation for further progress
Main report Definitions, reference level, registrations, inspections, evaluations and
recommendations, costs
Enclosure Basic material, supplementary material, drawings, photographs, form
8 © ISO 2006 – All rights reserved

5.3.2.3 Extent and costs
The extent of the survey is determined by
a) what items and fields are included in the performance survey;
b) the registration level;
c) whether a calculation of costs of the recommended actions is to be carried out.
The extent of the performance survey should be subject to continuous reassessment. Choice of registration
level is dependent on the purpose of the performance survey and on the performance of the construction
works. Before the registration level is chosen, it should be considered whether there is a need for a
preliminary inspection. An estimate of quantities should be included if the costs of the recommended actions
are to be calculated.
In the use of sampling examinations, i.e. that the performance registration only includes a limited selection of
items on the network level, or a limited part of a larger item on the object level, the number of samples should
be determined based on the
a) required reliability/certainty;
b) consequences of failure (economy, safety);
c) costs of extended examination (larger number of samples).
It should be decided whether all items of each type that exist within the area covered by the performance
survey (the entire population) should be included in the performance registration or whether a selection
(sample) should be made. If the area for performance survey includes a large number of identical items or
large areas of identical structure, it can be appropriate, in terms of both work and costs, to limit the
performance registration to a selection.
For some items there might be standards or regulations that determine the sample size.
Costing calculations of the recommended actions is a highly comprehensive task involving the preparation of
an estimate of quantities and research into the cost of earlier similar work. In order to determine the extent of
the overall task and the required use of time, it is important to clarify whether costing calculations are
necessary at all.
5.3.3 Planning
It should be established whether drawings and/or specifications of the item “as built” (or rebuilt) exist, and
whether there is any documentation on operating and maintenance-related performances, e.g. repairs,
maintenance work and improvements that have been made. The amount of basic material that needs to be
provided or prepared should be determined, depending on the type of documentation that exists and on the
extent of the performance survey.
For sampling examinations, the items should be selected at random, i.e. selected without the influence of any
prior knowledge about the items.
A plan for the performance survey that includes preliminary meetings, inspection forms, reporting including
documentation level, any presentation of results, and suggestions for further action should be prepared. It
should be agreed who is responsible for notifying the user and for providing the necessary access.
5.3.4 Registration of in-use conditions and performance levels
5.3.4.1 General — In-use conditions
As stated, RSL data comprise service-life data and reference in-use conditions, as well as corresponding data
on critical properties and performance requirements for subsequent service life evaluations. For each
individual in-use condition listed, the factor class it belongs to should be indicated. Statements indicating the
data quality should be included, for instance, information that the RSL data have been generated on the basis
of a systematic study or that data are critically reviewed by a third party.
A quantitative description of the reference in-use conditions in terms of the factor classes should be given (see
ISO 15686-8:—, 7.2).
The reference in-use conditions corresponding to Factor class D, indoor environment, and/or Factor class E,
outdoor environment, whichever is applicable, are to be quantified in terms of degradation agent intensities
characterizing the reference in-use environment. Alternatively to discrete values, ranges of such intensities or
standardized classes corresponding to certain ranges of intensities are accepted (see Annex C).
NOTE For further information, references are given to systems for classification of exposure environments for
families of materials in terms of corrosivity, i.e. ISO 9223 (which classifies time of wetness, SO and chloride),
ISO 12944-2 and ISO 11844. Such systems can be directly applied.
Recording environmental exposure and impact should consist of collecting existing or in-field measurements
and models of important climatic and pollution degradation agent’s data (i.e. temperature, rain, wind, local
pollution). Models should be used directly for assessment on network level, while evaluation of the
micro-environmental conditions should be carried out for single objects. In order to do so, local exposure
conditions such as topography, shelters, surroundings, etc. should be registered (see A.3.4).
5.3.4.1.1 Grading of Factor classes A, B, C, F and G
For the reference in-use conditions corresponding to each of the Factor classes A, B, C, F and G, quantitative
information provided by the source should be used whenever available.
If possible, a detailed description of the material or component should be given for Factor class A: quality of
components.
When, but only when, quantitative information is lacking for the in-use conditions within any of the Factor
classes A, B, C, F and G, a grading of the in-use conditions within that factor class should be made. Any
qualitative information provided should be valued and interpreted to correspond to one of the in-use condition
grades 1 to 5 in accordance with Table 5. If no information is available, this is indicated by the grade 0.
Occasionally, if the factor class is not applicable, it is indicated by NA.
NOTE In-use condition grading is a means to quantify qualitative (or fuzzy) information of reference in-use conditions.
An in-use condition grade is not the same as, and is not to be confused with, the value of the corresponding factor, but is
information required to estimate this factor.
From general information of the material or component tested, it should always be possible to quantify the
in-use condition corresponding to Factor class A into one of the in-use condition grades 1 to 5 (if no
quantitative information are provided by the source).
10 © ISO 2006 – All rights reserved

Table 5 — Options of grading in-use conditions of Factor classes A, B, C, F and G
In-use condition
Description Comment
grade
0 not available Should never be applied for Factor class A. Not to be applied for Factor
classes B, C, F and G when service life data are based on ageing tests in
accordance with systematic studies such as ISO 15686-2.
1 very high/mild —
2 high/mild —
3 normal —
4 low/severe —
5 very low/severe —
NA not applicable Should not normally be applied.
NOTE An in-use condition rating is not the same as the value of the corresponding factor, but a piece of information to estimate this
factor.
5.3.4.2 Performance recording
5.3.4.2.1 Critical property and performance requirements
As the service life of a component is always related to a required function of that component, the service life
should be defined and related to a critical property, see ISO 15686-8.
5.3.4.2.2 Performance degrees
The performance recording should be done on building and/or component level, and is expressed by means
of performance degrees (PD). The performance degree should be based on an evaluation of one or more
individual symptoms or on an overall evaluation of a set of symptoms and their level of deterioration and/or
level of performance (see Annex B). The symptoms should indicate the performance in relation to the
reference level on which the evaluation of the performance is based. Five performance degrees with the
following main significance should be used.
⎯ Performance degree 0: No symptoms
⎯ Performance degree 1: Slight symptoms
⎯ Performance degree 2: Medium
⎯ Performance degree 3: Strong symptoms
⎯ Performance degree 4: Totally unacceptable, including collapse and malfunction
Significance and determination of performance degrees may be based on symptom descriptions. The use of
symptom descriptions contributes to an increased objectivity in the expression of performance. Such symptom
descriptions may, for instance, be formatted as illustrated catalogues.
5.3.4.2.3 Performance degrees and in-use condition gradings
The performance degrees should be related to the quantitative description of the in-use conditions in terms of
the factor classes, see Annexes A and C. In practice, however, the observed PD is due to the influence of one
or more critical factors. For example, an observed PD of 2 can be due to a maintenance factor class of “low”,
equal to 4 (see Table 5), or simply to the fact that the ESL is surpassed, and that the PD definition should be
set to the defined performance level while all the other factors can be high grade.
The performance (and failure) should be documented, with specifications, drawings, sketches and
photographs, if appropriate. The extent of the symptoms may be specified in writing as a percentage of the
total amount, as specific quantities, or with a reference to normative references.
The reference level on which the significance and determination of performance degrees are based should be
specified. If the reference level is not generally available, this should be specifically documented. The
assignment of in-use condition grades to respective performance degrees may be defined by users in
accordance with individual needs.
In practice, parts of the performance control are carried out at performance registration. If failure is registered,
it should be specified together with the reference level on which the evaluation of failure is based.
5.3.5 Evaluation
5.3.5.1 Performance control
The registered performance should be checked against the predefined requirements, e.g. requirements set by
the authorities, the client and user requirements. If a negative deviation from the defined reference level is
proven, this constitutes a registered failure.
5.3.5.2 Prediction of (residual) service life
The (residual) service life should be predicted from the performance assessment of distributions of
performance degrees over the construction, and the limit states or acceptance levels. The level of
deterioration of a component can be related to the performance degrees directly, and when the damage
functions are known, the service life can be directly calculated (see Annex B). The development over time of
the performance degree and, subsequently, the service life, can also be calculated by using the Markovian
chain model (see Annex B). Distributions of in-use condition factors (and performance degrees) can also be
used to calculate the service life distributions of components of a construction (see Annex C). This is
extensively dealt with in ISO 15686-8:—, Clause 5. The performance degrees can also be correlated with
exposure environment to develop damage functions, which are the basis for mapping service life data (see
Annex C).
5.3.5.3 Causes and effect evaluation
Evaluation of causes should be considered important for SLP and evaluation of actions, as one action can
result in the removal of the causes/agents.
5.3.5.4 Failure
The performance survey should contain an evaluation of any failure during the performance registration or
performance control. If no failure is registered, the performance survey should still indicate that the evaluation
has been carried out to establish this.
Failure is of significance for the evaluation of actions and should be classified as follows.
a) No failure: Failure has not been registered and correct execution has been documented;
b) Possible hidden failure: Insufficient documentation to establish whether failure exists or not;
c) Failure: Failure has been registered (also used about an incorrect execution that has
been documented).
In the case of failure or possible hidden failure, it should be specified which type of defects have generated
the comment.
NOTE In the case of possible hidden failure, it is the responsibility of the client to decide whether to carry out further
examinations, including any destructive actions necessary to establish whether real failure exists.
12 © ISO 2006 – All rights reserved

In insufficiently documented construction works, there are numerous possibilities of hidden failure. In such
cases, it can be appropriate to state that the documentation is generally insufficient, i.e. assign the value 0
(see 5.3.4.1.1), and that it does not satisfy existing requirements and to carry out a general evaluation of
whether the possible hidden failure is real, instead of listing all possibilities for hidden failure.
EXAMPLE 1 If the render loosens then there is an unsatisfactory performance and the performance degree indicates
the extent. If this lies within the limit that can be accepted by the client and the authorities, no failure exists. If it is not
acceptable in relation to the defined reference level, a failure exists.
EXAMPLE 2 If it cannot be established how a building is attached to its foundation and there is no documentation on
this, a possible hidden failure exists.
5.3.5.5 Consequences
As a basis for risk analysis and recommendation of actions, the consequences of the registered performance
should be evaluated. The consequences are expressed by means of consequence degrees. The
consequence degree is established for one or more individual consequences or collectively for a set of
consequences.
Five consequence degrees should be used as follows.
a) Consequence degree 0: No consequences;
b) Consequence degree 1: Minor consequences;
c) Consequence degree 2: Medium consequences;
d) Consequence degree 3: Serious consequences;
e) Consequence degree 4: Catastrophic consequences.
The type of consequences on which the evaluation is based should be specified in each individual case.
EXAMPLE Consequences that can be used as a basis for evaluation include
a) safety (e.g. load-bearing capacity, fire safety);
b) health/environment (e.g. air quality, noise level);
c) aesthetics (e.g. surfaces);
d) economy (e.g. maintenance, renovation).
5.3.5.6 Risk
The risk should be evaluated and reported, and used as a basis for recommendation of actions. The risk
attached to a building element, construction element or work section is determined by the probability that a
non-acceptable performance (failure) or situation will occur or develop. This failure/situation inevitably has
resulting consequences.
The risk should be specified as low, medium, or high, and the consequences that have been used as a basis
for the specification of risk should be identified.
NOTE Low probability combined with serious consequences give the same risk assessment as high probability
combined with minor consequences.
The following two scenarios can occur.
a) Performance degree 0 but with registered failure or possible hidden failure. In this case, the probability
that performance degrees 1, 2, 3 or 4 will occur, and the resulting consequences, should be evaluated.
b) Performance degrees 1, 2, 3 or 4. The probability that the performance will deteriorate further, and the
resulting consequence should be evaluated.
EXAMPLE 1 Render on an exterior wall with performance degree 1, slight symptoms. The consequences with regard
to aesthetics are serious, the consequences with regard to economy/maintenance are medium, and the consequence with
regard to safety depends on location. The probability that the performance will deteriorate is high. The risk is high or
medium depending on the type of consequence on which the evaluation is based.
EXAMPLE 2 Possible hidden failure with regard to how a house is attached to its foundation. Consequences with
regard to economy and safety are serious if the house is blown away. The probability that this will happen depends on the
location of the house. The risk is low or high depending on the location of the house.
5.3.5.7 Actions
Recommended actions should be specified and given priority in accordance with the purpose of the survey.
When making recommendations for actions, it should be specified at what time the actions should be
implemented.
Actions can be of the following nature:
a) widening the scope of the performance survey;
b) detection of registered possible hidden failure;
c) planning of maintenance work in accordance with strategic goals and the action profiles linked to the
performance degrees.
5.3.6 Reporting
5.3.6.1 General
The report should contain the following main items:
a) introduction;
b) conclusion;
c) main report;
d) enclosure.
5.3.6.2 Introduction
The introduction should provide the following information:
a) the purpose of the performance survey;
b) identification of the item, e.g. with address, identification in the land register;
c) main structure, construction year/age;
d) extent and level of registration;
14 © ISO 2006 – All rights reserved

e) time of survey;
f) name of the client and contractor (and their representatives, such as the responsible inspector, etc.);
g) name of other parties involved (and their representatives).
5.3.6.3 Conclusion
The conclusion should contain the following items:
a) main conclusion/summary;
b) performance;
c) recommended actions;
d) costs/economy;
e) recommendations for further progress.
5.3.6.4 Main report
The main report should contain the following items:
a) the critical properties, the performance requirements (the reference level) on which the significance and
determination of performance degrees and failure are based;
b) the in-use conditions registrations;
c) evaluation of performance by checking against requirements/reference level;
d) assessment of residual service life;
e) evaluation of consequences;
f) evaluation of risk;
g) evaluation, recommendation and priority of actions;
h) any calculations of costs.
For all these items, the amount of documentation that should be included in the main report should be
assessed. What material should be included as enclosures should also be assessed (see 5.3.6.5)
5.3.6.5 Enclosure
Any basic material describing the item as built or rebuilt which is not part of the performance survey, and
supplementary material from the performance survey which is not necessary to include in the main report,
should be enclosed with the report.

ISO 15
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