EN 13084-9:2022

SLOVENSKI STANDARD
01-december-2022
Prostostoječi dimniki - 9. del: Upravljanje življenjske dobe - Nadzorovanje,
inšpekcijski pregled, vzdrževanje, sanacijski ukrepi in poročanje - Zahtevani
ukrepi in postopki
Free-standing chimneys - Part 9: Lifetime management - Monitoring, inspection,
maintenance, remedial and reporting; Operations and actions required
Freistehende Industrieschornsteine - Teil 9: Lebensdauermanagement - Überwachung,
Inspektion, Wartung, Sanierungsmaßnahmen und Dokumentation; Notwendige
Maßnahmen und Verfahren
Cheminées autoportantes - Partie 9 : Gestion du cycle de vie - Surveillance, inspection,
maintenance, mesures correctives et établissement de rapports ; opérations et actions
requises
Ta slovenski standard je istoveten z: EN 13084-9:2022
ICS:
13.020.60 Življenjski ciklusi izdelkov Product life-cycles
91.060.40 Dimniki, jaški, kanali Chimneys, shafts, ducts
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 13084-9
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2022
EUROPÄISCHE NORM
ICS 91.060.40
English Version
Free-standing chimneys - Part 9: Lifetime management -
Monitoring, inspection, maintenance, remedial and
reporting; Operations and actions required
Cheminées autoportantes - Partie 9 : Gestion du cycle Freistehende Industrieschornsteine - Teil 9:
de vie - Surveillance, inspection, maintenance, mesures Lebensdauermanagement - Überwachung, Inspektion,
correctives et établissement de rapports ; opérations et Wartung, Sanierungsmaßnahmen und Dokumentation;
actions requises Notwendige Maßnahmen und Verfahren
This European Standard was approved by CEN on 26 September 2022.

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

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

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13084-9:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Maintenance and inspection . 7
5 Repair works . 22
6 Decommissioning and demolition . 24
Annex A (informative) Guidelines for provisions concerning the use of work equipment provided
for temporary work at a height . 28
A.1 General. 28
A.2 Specific provisions regarding the use of ladders . 29
A.3 Specific provisions regarding the use of scaffolding . 29
A.4 Specific provisions regarding the use of rope access and positioning techniques . 30
A.5 What to consider when planning work at height . 31
Annex B (informative) Examples of damages with associated level of criticality . 32
Bibliography . 34
European foreword
This document (EN 13084-9:2022) has been prepared by Technical Committee CEN/TC 297 “Free
standing industrial chimneys”, 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 April 2023, and conflicting national standards shall be
withdrawn at the latest by April 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document is Part 9 in a series of standards and as such is not a stand-alone document. The
requirements in Parts 1 to 8 of this series are integral to Part 9.
EN 13084, Free-standing chimneys consists of the following parts:
— Part 1: General requirements
— Part 2: Concrete chimneys
— Part 4: Brick liners — Design and execution
— Part 5: Material for brick liners — Product specifications
— Part 6: Steel liners — Design and execution
— Part 7: Product specifications of cylindrical steel fabrications for use in single wall steel chimneys and
steel liners
— Part 8: Design and execution of mast construction with satellite components
— Part 9: Life-Time Management — Monitoring, Inspection, Maintenance, Remedial and Reporting;
operations and actions
The following documents additionally apply:
— EN 1993-3-1, Eurocode 3 — Design of steel structures — Part 3-1: Towers, masts and chimneys —
Towers and masts
— EN 1993-3-2, Eurocode 3 — Design of steel structures — Part 3-2: Towers, masts and chimneys —
Chimneys
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
Introduction
EN 1990 indicates as a principle that to ensure adequate durability of the structure, several factors should
be considered including the expected maintenance during the period of project use.
The same standard also states as a principle that proper inspections and maintenance according to the
procedures specified in the project documentation should be stated to ensure the required level of
reliability.
EN 13084-1 requires in Clause 7 that the chimneys be checked at regular intervals by an expert. The
interval should not exceed two years between any checks. A written report should include
recommendations for maintenance and repair.
When planning new-build or refurbishment projects, architects, designers, manufacturers and
contractors have duties under European Directive 92/57/EEC 24th June 1992 on the implementation of
minimum safety and health requirements at constructions sites), to consider the need for work to be
carried out at height over the lifespan of a building, e.g. to clean, maintain and repair it, and they should
design out the need to work at height if possible.
It is therefore necessary to specify the various operations to be carried out both in inspection and
maintenance to clarify the various points of intervention to prolong the duration of use and reliability of
the structure. This document describes these operations according to the summary of contents on page
2.
1 Scope
This document covers the general requirements and the basic criteria for lifetime management of all
kinds of free-standing chimneys, comprising monitoring, inspection, maintenance, repair, reporting, and
necessary actions and procedures. This document applies to any windshield, single stack, tower, mast
and liner covered by the EN 13084 series.
The Lifetime management considers the original structural and operating design of the structurally
independent chimneys under operational conditions and other actions to verify that mechanical
resistance and stability and safety in use are continued at the designed for level as expected and/or
adapted to changes in the operational requirements of the structure and/or its environment.
NOTE In other parts of the EN 13084 series, rules will be given where chimney products in accordance with
EN 1443 (and the relating product standards) can be used in structurally independent chimneys.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 365, Personal protective equipment against falls from a height — General requirements for instructions
for use, maintenance, periodic examination, repair, marking and packaging
EN 1856-1, Chimneys — Requirements for metal chimneys — Part 1: System chimney products
EN 1990, Eurocode — Basis of structural design
EN 1993-1-11, Eurocode 3 — Design of steel structures — Part 1-11: Design of structures with tension
components
EN 13084-1, Free-standing chimneys — Part 1: General requirements
EN 62305 (all parts), Protection against lightning
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 13084-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
condition monitoring
visual inspection, on a regular basis, of the structure and its components to identify any significant change
3.2
criticality level
index of the severity of a failure or a fault combined with the probability or frequency of its occurrence
defined with three possible values: high, medium, and low
3.3
design working life
period for which a structure is expected to be used for its intended purpose to ensure durability against
environmental actions and fatigue
3.4
expert
person who has scientific and/or technical theoretical and practical knowledge in a field of activity
validated by approved education certificates and / or as well as in-depth knowledge and practical skills
validated by a recognized experience of a professional activity of several years in the field of activity
concerned
3.5
general inspection
assessment of the complete structure by an expert to ensure that it is still in serviceable condition or to
indicate necessary maintenance or repairs
3.6
maintenance operations
combination of all technical, administrative, and managerial actions during the life cycle of an item
intended to retain it in, or restore it to, a state in which it can perform the required function
3.7
repair operations
physical actions to be taken or taken to restore and or maintain the required function of a faulty item
3.8
windshield
structural independent shell designed for load bearing purposes and to protect and support the liner(s),
flue from wind actions
4 Maintenance and inspection
4.1 General structure of the maintenance operations
Eurocode EN 1990 requires that the structures shall be designed such that deterioration over its design
working life does not impair the performance of the structure below that intended, having due regard to
its environment and the anticipated level of maintenance. The following should also be considered:
— the intended or foreseeable use of the structure (chemical and thermal loads caused by the conveying
of flue/exhaust gases, the operating of the installation - on-/off operation, bypass-operation, wet
stack -, foreseeable and not foreseeable operational interruptions and shutdowns, etc…;
— the required design criteria;
— the expected environmental conditions;
— the composition, properties and performance of the materials and products;
— the properties of soil;
— the choice of the structural system;
— the shape members and the structural detailing;
— the quality of workmanship and the level of control;
— the protective measures;
— the intended maintenance during the design working life.
For all types of structurally independent chimneys structures, the maintenance operations shall be done
according to the following steps to preserve durability and performances:
— maintenance required by the chimney manufacturer (see 4.2);
— survey and maintenance to be done by the owner/operator (see 4.3);
— general inspection of the installation (see 4.4).
4.2 Maintenance and inspection plan by the manufacturer
As required by EN 1990, the manufacturer should include the inspection and maintenance plans in the
project documentation (Operating and Maintenance manual) delivered at the commissioning and
handover phase of a new project, to ensure the required level of reliability as per the structure and plant
design and calculations.
The manufacturer’s maintenance and inspection plan shall at least include all relevant points of 4.3 for
chimney and equipment and a full set of the structural design calculations and thermal fluid design
calculations.
If necessary, depending on the project specifications, manufacturers can provide more restrictive
recommendations for some or all parts and equipment.
If no maintenance plan was provided by the manufacturer, such a document adapted to the specifications
of the project can be drafted by a chimney expert.
4.3 Maintenance and inspection plan by the owner/operator
4.3.1 Maintenance operations
4.3.1.1 General
It is the responsibility of the owner to maintain the installation in a good state. To guarantee the good and
safe operation of the installation and to spot any deterioration which could lead to a fault, the owner shall
ensure all the maintenance and inspection operations detailed in the Operating and Maintenance manual
provided by the manufacturer.
4.3.1.2 Introduction
Without any other recommendations, the following maintenance operations shall be carried out.
4.3.1.3 Safety valves
If the installation includes explosion or implosion relief valves, these safety systems shall be dismantled
and sent back to the manufacturer at least once a year to be recalibrated and reconditioned.
NOTE A spare new set can be kept on site to allow for continuous use of the plant.
4.3.1.4 Cleaning operations
The following cleaning operations shall be carried out:
— cleaning of base drains;
— cleaning of condensate drain-pipes;
— cleaning of rainwater drain-pipes;
— sweeping of flue liners and connecting flue pipes with appropriate brushes, plastic-based for
stainless steel flues and metallic-based for mild steel flues;
— if a silencer is installed, cleaning of the condensate pipes and the baffles if applicable.
4.3.1.5 Coating system
To achieve the stated coat life span and increase the life span of the finish, it is necessary to provide on-
going site maintenance / repair and/or overcoating of the paint finish. This operation shall be carried out
as per the paint manufacturer’s recommendations and requirements for site application with the
objective to provide the same level of protection (where possible taking into full account the conditions
of on-site application and environment) in durability and time as per the original factory finished coating
specification.
For corrosion protection of steel structures by protective paint systems, EN ISO 12944-8:2017 provides
requirements on maintenance works.
4.3.2 Condition Monitoring
4.3.2.1 General
Regular condition monitoring is required and should extend to all visually and audibly recognizable
changes to the structure and components.
This inspection is carried out from ground level and/or-by entering the chimney’s accessible space if any.
The chimney shall be inspected by using all available fixed ladders and platforms. Binoculars, cameras
with long-distance lenses and drones with cameras can be appropriate equipment to inspect all the
surfaces of the chimneys.
Visual inspection of the following elements shall be carried out.
4.3.2.2 Windshield and liner(s)
As a minimum, the following points shall be checked on the windshield and liner(s):
— leaning, sinking and loosening of guy wires;
— circular oscillation of the chimney of large amplitude even under low wind speeds;
— cracks, splits, perforations, impacts, and any structural damage;
— loosening and oxidation of nuts and bolts (anchorage, joints, base plate, guy wires);
— jamming of inspection doors and measuring plugs;
— piece of material on the surrounding grounds for a brick or concrete chimney;
— staining, dripping, corrosion marks;
— colouring, stains or runs of condensates on the windshield or liner(s);
— large amount of condensation inside the windshield.
4.3.2.3 Thermal insulation (Liner and/or windshield)
As a minimum, the following points shall be checked on thermal insulations:
— deterioration of the insulation material;
— deterioration of the cladding if any like hole, bump, twisted or missing elements;
— trace of liquid runoff.
An Infrared image examination of hot chimneys could be used to identify hot spots and thermal bridges
where insulation’s thermal properties are altered or where the insulating function is not given any longer.
4.3.2.4 Equipment and accessories
As a minimum, the following points shall be checked on equipment and accessories:
— presence of loose elements (platform plates or gratings, ladder parts, cladding plates, lightning
protection, cables, etc.);
— discontinuity in the lightning protection system;
— deterioration of the daytime or night-time aircraft warning systems (lights or painting);
— in silencers, damage to the absorbing material or its casing (tear), obstruction of condensate pipes,
issue with general design (impact, perforation, condensate staining);
— physical deterioration/burst or any trace of leakage on the damper if any.
It is the responsibility of the owner/operator to make sure that any additional local requirements or
manufacturer requirements in terms of frequency and/or content are taken on board.
4.3.3 Frequency (Intervals)
Maintenance operations and condition monitoring shall be carried out no later than 3 months after the
chimney / exhaust has been commissioned and put into operation to detect any potential troubles on the
plant.
Afterwards, the maintenance operations and condition monitoring shall be performed every 6 months or
before restart after a long-term shutdown, or after any extraordinary occurrences like heavy storms,
unusually heavy icing.
The frequency may be reduced according to the Operating and Maintenance manual provided by the
manufacturer.
For specific cases where installations work continuously for periods longer than six months, the
maintenance and inspection of the external parts of the chimney shall be carried out at the normal
frequency. The internal parts of flue liners, connecting ducts and specific equipment shall be inspected
each time the installation is stopped.
4.3.4 Record and repair actions if necessary
The maintenance operations and condition monitoring shall be recorded in a report which shall be
attached to the operating and maintenance manual for future record reviews.
Any anomaly spotted during the condition monitoring shall be reported to the chimney manufacturer or
to an expert without delay. The further course of action will then be advised by the chimney manufacturer
or by the expert according to the risks presented by the installation.
4.4 General Inspection by a chimney expert
4.4.1 General
The general inspection will assess the performance and the state of the installation as a whole, according
to the design operating requirements of the chimney(s) and plant(s).
The objective is to ascertain that the chimney, lining and components are all still in serviceable condition
and fulfilling their designed requirements and tasks and to indicate if further actions like maintenance or
repair operations are necessary.
This inspection is to be entrusted to an expert who can also assess the structural conditions of the
structures.
4.4.2 Frequency (intervals)
A first general inspection shall be carried out no later than 3 to 12 months after the chimney / exhaust
has been commissioned and put into operation. This time frame starts at chimney erection for chimneys
with dampers and/or pre-stressed bolted connection flange joints.
At a period as recommended in the operating and maintenance manuals of the manufacturer and at a
minimum of every 2 years, the installation shall be inspected by a chimney expert.
NOTE National rules could impose different frequency for the inspection of the chimney or part of the chimney.
For specific cases where installations work continuously for longer than two years, the inspection shall
be limited to a partial inspection to the parts of the chimney with safe access. The operating data to
determine the degree of chemical stress should be checked. Each time the plant is stopped, a full general
inspection shall be performed.
Additionally, a general inspection shall be planned at the expected end date of the chimney’s, exhaust’s
operational lifetime. During this end date inspection, the expert can give his agreement to prolong/extend
the life expectancy of the chimney without any additional work or recommend repair and renovation
work that would enable the expected lifespan of the chimney, exhaust to be extended.
A warrantee issue shall require the manufacturer/supplier to carry out an inspection report and
corrective actions as required in accordance with the warrantee specification.
Depending on the conditions of use and on the potential risk for the structure of the stack and its
environment, the expert or the manufacturer of the chimney can recommend a general inspection
frequency shorter than the normal 2 years interval based on the following criteria:
— type of fuel;
— intermittent or continuous operation;
— thermal and chemical attacks;
— thermal shocks, due to sudden change of temperature during operation and/or too quick start-up or
shutdown.
4.4.3 Stages
4.4.3.1 General
Inspection and maintenance shall consist of the following stages.
4.4.3.2 Preparation
Check of the actual versus design operating conditions of the chimney, lining and equipment in the project
documentation.
Analysis of the records of maintenances and inspections operations, repairs and modification operations,
and previous general inspection reports.
Identification of particularly vulnerable zones.
Determination of the necessary resources for the visual inspection, if necessary supplemented by
equipment for measurements and sampling.
Analysis of the access possibilities considering the operating situation, if necessary, organization of
auxiliary means such as crane basket, inspection platform, rope access.
4.4.3.3 Execution
As close as possible visual inspection.
Support of visual inspection by use of opto-electrical aids such as thermal cameras, remote-controlled
camera systems.
Taking of material samples, if its necessity has been identified during the preparation for inspection and
agreed with the operator.
Carrying out of measurements (e.g. material thickness, strength, etc…) if their necessity has been
identified during the preparation for inspection and agreed with operator.
4.4.3.4 Documents for the report
The following documents shall be prepared for the report:
— general impression,
— analysis of visual observations,
— analysis of laboratory tests,
— analysis of measured values,
— evaluation of the condition development by comparison with previous inspection reports,
— determination of the criticality level of the detected defects,
— recommendation of further action in terms of scope and timing of next inspection, remediation of
deficiencies, repair measures.
For detailed description of the report, see 4.4.9.
4.4.4 Windshields
4.4.4.1 General
The external and the internal (if possible/accessible) condition of windshields of all types and their
components shall be inspected as detailed here under. In addition to the requirements of 4.3.2.2 and
4.3.2.3, the following points shall be included in the process as a minimum:
— carry out close visual examination (as planned in the preparation phase) over the complete surface
of the external face of the shell. Where / when necessary, carry out an ultra-sonic survey of chimney
shell in sufficient detail to allow any significant loss of section to be detected;
— examine the functionality and condition of penetrations such as flue gas inlets;
— examine the functionality and condition of ventilation and inspection openings, revision accesses;
— examine and inspect all fixed safety and access equipment, e.g. fall arrest system, ladders, platforms,
handrails, nesting boxes, aircraft warning lights, measuring equipment, etc;
— examine any installed lightning protection system for compliance with current standards and carry
out electrical tests for continuity and resistance to earth.
4.4.4.2 Specific provisions for steel chimneys
It is an important requirement that the integrity and thickness of the structural shell and all structural
components are determined and checked against the original manufactured design and the built
thickness; one acceptable method for doing so would be to use ultrasonic testing.
The internal and external surface of steel chimneys shall be inspected, for large diameter preferably by
close examination from a bosun’s chair or similar means of support access and/or a CCTV camera
inspection for smaller diameter chimneys and liners, to ascertain that the structural shell, the chimney
and the lining are still in serviceable condition and fulfilling design requirements to an acceptable safe
level of criticality.
The base plate retaining bolts and their protective cover shall be examined: if necessary, perform an
ultrasonic examination of the retaining bolts securing the structural duct to the foundation / building to
determine the extent of deterioration / corrosion.
Inspection of all joints and applied torque loadings on flanges: their mechanical fixings and torque
requirements will be determined by the expert carrying out the inspection, to the load levels as defined
by the original designer. When necessary, remove fixings from each flange for microscopic examination
for defects. Bolts should then be tested for ultimate tensile failure for comparison against the required
rating of the bolts.
Flanges should be inspected to see if there is a build-up of rust between them, as the pressure of rust
build-up can overload the bolts in tension.
Particular attention shall be given to the condition of the bolts in bolted connections. Selected bolts in
critical areas shall be removed and replaced by new bolts. The removed bolts should be inspected and
tested as necessary.
Rivet heads on riveted chimneys shall be examined to ascertain that they are secure and have not eroded
to a dangerous degree.
Holding down bolts, flanged bolts, structural flanges, guy wire fittings, etc., shall be examined for security
and tension and, if necessary, be re-torqued, cleaned, greased and/or replaced.
The inspection shall include all protective and/or decorative or other surface finish on the exterior of the
chimneys to be examined. For example, for Metal painting - The exterior of a steel chimney and/or
chimney components may be protected from atmospheric and/or flue gas corrosion by the application of
a painted coating usually carried out at manufacture stage in accordance with EN ISO 17834,
EN ISO 12944, or an equally appropriate standard. The paint finish will have a stated estimated
maintained life span.
The same points will also apply to inspecting and maintaining Supporting-Masts structures.
4.4.4.3 Specific provisions for concrete chimneys
In addition to the generally applicable specifications according to 4.4.4.1, the concrete windshields shall
be inspected for:
— exposed reinforcement,
— existing concrete spalling or signs of spalling of the concrete cover,
— hollow spots, e.g. around sliding bar channels,
— location, shape and width of cracks,
— condition of the coating,
— sintering out,
— signs of corrosion,
— condition of segmental or construction joints,
— presence of pop-outs,
— exposed aggregate due to erosion, washout, inadequate compaction during construction,
— presence and condition of mouth cover and ventilation in decommissioned chimneys.
Further investigation may be recommended to evaluate aging, exposure of the surrounding area to
spalling, etc:
— reinforcement detection,
— full surface tapping,
— drill core sampling,
— carbonation measurement,
— strength analysis,
— sample analysis for microstructure, contaminants, etc.
4.4.4.4 Specific provisions for masonry chimneys
In addition to the generally applicable specifications according to 4.4.4.1, the masonry windshields shall
be examined for:
— location, shape and width of cracks,
— erosion of joints,
— opening of the bearing and butt joints,
— spalling of the joints,
— driving reactions,
— moss / fouling,
— sintering out,
— damage to the fire skin,
— changes in the structure,
— condition of the masonry bandages,
— condition of capping at facing walls, wall thickness cracks, mouths,
— erosion of stone surfaces,
— presence and condition of mouth cover and ventilation in shut down chimneys,
— measurement of axiality by several measurement points distributed over the height.
Further investigation may be recommended to evaluate aging, risk to surrounding area from spalling,
etc., as appropriate:
— drill core sampling,
— strength analysis,
— sample analysis for microstructure, pollutants, etc.
4.4.5 Liners
4.4.5.1 General
In addition to the requirements of 4.3.2.2 and 4.3.2.3, the following points shall be checked as a minimum
on the liner:
— functionality and condition of inspection/revision accesses and measuring plugs;
— jamming of inspection doors and measuring plugs;
— clogging up (unusually large deposit of soot in flues and inlets);
— cracks, splits, perforations, impacts;
— pooling of water or condensates in drains at the base of the flues / blockage of the condensate drains;
— integrity and functionality of the liner supports;
— integrity and functionality of the compensators;
— reduction in thickness, due mainly to the following:
o thermal shocks,
o chemical attacks,
o erosion and wear,
o frost action;
— cracks and their characteristics such as location, length, orientation, width,
— restriction of free moveability of the liner section due to:
o local or global deformation caused by chemical reactions and/or temperature influences,
o reduced efficiency of joints due to solid deposits,
o lack of clearance between liner(s) and their supports.
4.4.5.2 Specific provisions for steel liners
In addition to the requirements of 4.4.5.1, the following points shall be checked on the steel liner as a
minimum:
— appearance of corrosion marks;
— integrity and usability of expansion joints (note: metal expansion bellows have a defined cyclic life
period requiring regular replacement);
— integrity of welded, flanged, and spigot joints;
— inspection of all joints, push-fit and flanged. Mechanical fixings and torque requirements of flanged
joints will be determined by the expert carrying out the inspection. When necessary, remove fixings
from each flange for microscopic examination for defects. Bolts should then be tested for ultimate
tensile failure for comparison against the required rating of the bolts;
— corrosion at the terminal, base, and drain sections of the liner;
— liner thickness is still within design tolerances;
— condition of changes in direction (e.g. elbows and tees).
4.4.5.3 Specific provisions for masonry liners
In addition to the generally applicable specifications according to 4.4.5.1, the liner made of masonry shall
be examined for:
— position, shape and width of the cracks,
— axiality of the inner pipe or inner pipe sections,
— damage from constraints in transition areas and in the mouth area,
— condition and tightness of the transitions of the liner sections and the duct inlets,
— deposits or caking,
— erosion of joints,
— opening of bearing and butt joints,
— spalling of the joints,
— drifting reactions,
— damage of the fire skin,
— changes in the structure,
— erosion of stone surfaces.
4.4.6 Thermal insulation
The condition of the thermal insulation has a major influence on the service life of the structure and shall
therefore be evaluated during the inspection; as a minimum, the following shall be checked:
— signs on the structure of non-intact insulation (e.g. locally damaged coating, temperature linked
cracks). In case of suspicion, further investigations may be recommended such as infrared imaging
or local opening of the structure (inspection window);
— incompleteness of thermal insulation (thermal bridge). An Infrared image examination of hot
chimneys shall be used to identify hot spots and thermal bridges;
— moisture in the thermal insulation;
— thickness of insulation readings to be carefully plotted to match each inspection window for future
comparison and ensure that inspection apertures to the insulation are adequately sealed against
water ingress on completion of an inspection;
— condition of the fastening and cladding of the thermal insulation.
The design of the chimneys with inclusion of accessible spaces facilitates the inspection of the insulation
and safe working conditions.
Insulation defects may be often characterized as high level of criticality since they are a major cause of
damages to liners and structure, so safety of the persons and integrity of the structure may be altered.
4.4.7 Masts and prefabricated elements
Support masts are used as structural load bearing structures, like windshields do. Therefore, all clauses
of 4.4.4.2 apply.
Prefabricated system chimneys according to EN 1856-1 shall be inspected according to 4.4.5 and 4.4.6.
When guy wires are used to fix the mast, those elements shall be inspected regarding performances
requirement indicated in EN 1993-1-11.
4.4.8 Specific provisions for additional equipment
4.4.8.1 Horizontal chimney, duct and/or flue
In addition to the requirements of 4.3.2.4, the following points shall be inspected as a minimum:
— integrity and stability of all horizontal Chimney/ Duct / flue welds and sectional joints;
— excessive build-up of tar, soot / dust deposits within and blocking the flue passage(s);
— deflection of the horizontal pipe (sagging) between supports should not be more than 1,5° at the mid-
point between supports and/or in accordance with manufacturer’s instructions;
— adequate fall for drainage is maintained and drainage is free flowing to the drain point;
— drain points are clear and functioning correctly;
— all support steel work and fixings integrity and stability is functioning correctly within the design
limits and is not subject to excessive corrosion;
— insulation and cladding are in good state of repair and functioning correctly;
— the horizontal chimney should be maintained as necessary to ensure that the construction remains
in good condition. Any component showing signs of deterioration which affects performance should
be replaced under professional advice and any evidence of leakage identified by smoke staining /
testing should be rectified.
4.4.8.2 Lightening conductor protection system
Lightning protection is fundamentally installed to reduce the risk of “loss of human life” and “loss of
service to the public” in accordance with EN 62305 (all parts). The electricity at work regulations 1989
states that “all systems shall be maintained so as to prevent, so far as is reasonably practicable, danger”.
As such it shall be considered at a “High Level of Criticality”.
The test of the lightning protection during the inspection is essential for the safeguard of structures, their
contents and the lives of personnel working in the building’s environment. Annual maintenance is to
ensure the lightning protection system’s longevity, efficiency, safety. It is where possible to be maintained
at the same standard level as when it was first commissioned and shall be in full compliance with
EN 62305 (all parts). The effectiveness of the Lightning Protection System may be reduced over time due
to physical damage, corrosion, adverse weather conditions, or consequently of additions or alterations to
the structure under protection).
4.4.8.3 Ladder, bridge, and platform
Ladders, bridges and platforms should be inspected according to the standard to which they were
installed and commissioned.
As a minimum, the following points shall be inspected:
— Strength requirements: The ladder, bridge, platform elements shall be inspected to ensure that they
continue to meet the requirements of the original design;
— Trap doors shall be inspected to confirm proper and safe operation;
— Safety cages and rest platforms shall be inspected to ensure all fixings are secure and that clear access
has been maintained;
— Fall arrest systems shall be checked against manufacturer's requirements and EN 365 to confirm
continued safe operation and life expectancy;
— Corrosion protective coatings shall be inspected and repaired as required.
4.4.8.4 Dynamic damper
As a minimum, the following points shall be inspected:
— to ensure that the ultimate limit state where many cycles of loading cause cracks to develop in the
shell plate and that by load cycles it has not or will not lead to rupture or failure;
— the mechanical movement of the damper meets the original designed requirements to achieve the
required performances of the chimney;
— Inspected for corrosion internally and externally.
In addition to the above-mentioned points:
For tuned mass dampers:
— check for the presence of deterioration of the mass supports;
— check for the free guidance/movement of the mass;
— check the level of oil in case of damping by oil. Value shall be in accordance with design requirements.
For tuned Liquid dampers:
— check the level of liquid. Value shall be in accordance with design requirements;
— check the glycol concentration into the water with a refractometer for example. Value shall be in
accordance with design requirements;
— check the pH of the water using ph-indicator strips for example. Value shall be in accordance with
design requirements. (The decomposition of the glycol over the time produces acids which may
corrode the damper walls, produces water leakage, and so cause damper dysfunction with a high risk
for the structure).
4.4.8.5 Silencer
As a minimum, the following points shall be inspected:
— damage to the absorbing material or its casing (tear);
— damage to the perforated sheets (corrosion marks, crack, or disassembly);
— obstruction of condensate pipes;
— issue with general design (impact, perforation, condensate staining).
4.4.8.6 Explosion/implosion relief valve
As a minimum, the following points shall be inspected:
— the mechanical movement of the explosion/ implosion relief valve meets the original designed
requirements to achieve the required performance requirements of the chimney and the plant it is
serving;
— inspected for internal and external corrosion;
— all ‘explosion panels’ are still within the useable life expectancy.
4.4.8.7 Draft regulator
As a minimum, the following points shall be inspected:
— no mechanical blocking of the regulator;
— no soot deposit inside the regulator;
— the mechanical movement and settings of the regulator meets the original designed requirements to
achieve the required performance of the chimney and the plant it is serving;
— inspected for internal and external corrosion.
4.4.8.8 Guide type fall arrester and other fall arrest systems
As a minimum, it shall be checked that:
— The maintenance guidelines and requirements of “EN 365, Personal protective equipment against falls
from a height” are adhered to and followed;
— The manufacturers requirements and guidance are respected to confirm continued safe operation
and life expectancy.
4.4.8.9 Night and day markings and Aircraft warning Light
As a minimum, the following points shall be inspected:
— the lights and any back up system shall be checked to confirm that it meets the original design brief
requirements for continued service until the next planned inspection;
— the operation of the “Backup bat
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