prEN 15780

SLOVENSKI STANDARD
01-junij-2008
3UH]UDþHYDQMHVWDYE.DQDOLýLVWRþDSUH]UDþHYDOQLKVLVWHPRY
Ventilation for buildings - Ductwork - Cleanliness of ventilation systems
Lüftung von Gebäuden - Luftleitungen - Sauberkeit von Lüftungsanlagen
Ventilation des bâtiments — Réseaux de conduits — Propreté des systèmes de
ventilation
Ta slovenski standard je istoveten z: prEN 15780
ICS:
91.140.30 3UH]UDþHYDOQLLQNOLPDWVNL Ventilation and air-
VLVWHPL conditioning
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
DRAFT
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2008
ICS 91.140.30
English Version
Ventilation for buildings - Ductwork - Cleanliness of ventilation
systems
Lüftung von Gebäuden - Luftleitungen - Sauberkeit von
Lüftungsanlagen
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 156.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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 Management Centre has the
same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15780:2008: E
worldwide for CEN national Members.

Contents Page
Foreword. 4
1 Scope. 5
2 Normative references . 5
3 Definitions. 6
4 Symbols and units . 7
5 Criteria for cleanliness and assessment . 7
5.1 General. 7
5.2 Assessment of the need for cleaning . 7
5.3 Selection of cleaning method . 8
5.4 Determination of cleaning interval . 8
5.5 Assessment of the result of cleaning . 8
6 Methodology. 8
6.1 General methodology . 8
6.2 Assessment of the need for cleaning . 10
6.2.1 General. 10
6.2.2 Inspection plan. 10
6.2.3 Evaluation methods of dust accumulation. 10
6.3 Cleaning plan. 13
6.4 Cleaning methods. 14
6.5 Assessment of the result of cleaning . 14
7 Evaluation and reporting. 14
7.1 Evaluation of cleaning. 14
7.2 Cleaning report. 15
Annex A (informative) Cleanliness classes . 16
A.1 General. 16
A.2 Application in general. 16
A.3 Assessment frequency recommendation. 16
Annex B (informative) Example of cleaning plan . 18
Annex C (informative) Air handling units – specific guidance . 20
C.1 General. 20
C.2 Recommendations for normal applications. 20
C.2.1 Casing, including accessibility/access doors . 20
C.2.2 Filters. 20
C.2.3 Humidifiers . 21
C.2.4 Coils. 21
C.2.5 Sound attenuators . 21
C.2.6 Fan position and cleaning, including fan motors. 21
C.2.7 Drainage and prevention of condensation. 21
C.3 Units for special applications . 21
C.4 Inspection aspects. 22
Annex D (informative) Filters – Specific guidance. 23
Annex E (informative) Humidifiers – specific guidance . 24
E.1 General. 24
E.2 Humidifiers for normal applications . 24
E.3 constructional details Humidifiers for special applications, additional aspects . 24
Annex F (informative) Ductwork – specific guidance . 25
F.1 Application of cleanliness levels for installation. 25
F.2 Application of cleanliness levels - airtightness. 27
Annex G (informative) Terminal devices and units – specific guidance . 28
Bibliography . 29

Foreword
This document (prEN 15780:2008) has been prepared by Technical Committee CEN/TC 156
“Ventilation for buildings”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.

1 Scope
This Standard applies to ventilation and air conditioning systems and defines the initial assessment
criteria of cleanliness, cleaning procedures of these systems, and the validation of the effectiveness of
cleaning applies also to products, which conform to EN 1505, EN 1506, EN 13053, EN 13180 and
EN 13403, used in air conditioning and ventilation systems defined in the scope of CEN/TC 156.
This standard specifies requirements and procedures necessary in assessing and maintaining the
cleanliness of ventilation, including:
 how to assess the need for cleaning (visual, measurements);
 assessment frequency (general guidance);
 selection of cleaning method;
 how to assess the result of cleaning.
This standard is a parallel standard to EN 12097, which specifies requirements for dimension, shape
and location for access panels for cleaning and service in ductwork systems
This standard is made as an umbrella standard with informative annexes that can be added over time
with the following topics:
Air Handling Units (AHU)
Filter
Humidifiers
Ductwork
Terminal devices
The main target groups of this standard are building owners, services companies, maintenance
companies, end users and consultancy and control companies.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies.
EN 1505, Ventilation for buildings — Rectangular sheet metal air ducts and duct fittings —
Dimensions
EN 1506, Ventilation for buildings — Circular sheet metal air ducts and duct fittings — Dimensions
EN 12097, Ventilation for buildings — Requirements for ductwork components to facilitate
maintenance of ductwork systems
EN 12792, Ventilation for buildings — Symbols and terminology
EN 13053, Ventilation for buildings — Air handling units — Ratings and performance for components
and sections
EN 13180, Ventilation for buildings — Ductwork — Dimensions and mechanical requirements for
flexible ducts
EN 13403, Ventilation for buildings Non metallic ducts — Ductwork made from insulation ductboards
EN 13779, Ventilation for non-residential buildings — performance requirements for ventilation and

room-conditioning systems
EN 14239, Ventilation for buildings —- Measurement of ductwork surface area
3 Definitions
For the purposes of this European Standard, the definitions given in EN 12792 and the following
apply.
3.1
acceptable cleaning level
the amount of dust and other impurities shall not exceed the given limit values
3.2
acceptable cleaning result visually
no loosened dust is detected visually on the duct surface after cleaning
3.3
acceptable dust accumulation
limit value of dust accumulated in an air duct, defined by one of the methods defined in this standard
3.4
cleanliness
cleanliness of the ventilation system and/or its components: the state of the ventilation system and/or
the components, in which the amount or concentration of contaminants is below a specified level
3.5
cleanliness level
in the scope of this standard, there are three cleanliness levels: basic (A), intermediate (B) and
advanced (C). For each level, this standard specifies certain characteristics as default values in an
informative way
3.6
ductwork surface area
the surface area (m ) of the ductwork determined according to EN 14239
3.7
total joint length
the length (m) of joints resulting from the installation of the ductwork
3.8
visually clean
no loosened dust is detected on surfaces visually
3.9
visual inspection
a subjective method to evaluate cleanliness level of surfaces
4 Symbols and units
For the purpose of this standard, the symbols and units given in EN 12792 apply.
5 Criteria for cleanliness and assessment
5.1 General
NOTE REHVA Guidebook "Criteria for the cleanliness of ventilation systems and components" specifies in
detail the items mentioned in this chapter. Cleanliness classes and their applications are introduced in Annex A
The key issue is to design and build the whole ventilation system so that it can be kept clean enough
during the whole lifetime of the installation. The following requirements, as well as the methodology
described in Clause 5, can be also applied to air handling units (according to EN 13053) and entire
systems (see EN 13779, Annex A)
Therefore it is necessary to specify the cleanliness criteria from the beginning and include in the
specification both design and installation issues and means to maintain a sufficiently clean ventilation
system for its whole lifetime. The design and installation aspects include (as a minimum):
Production of the system components
Delivery to site
Site storage
Installation
Protection of components after installation
NOTE Annex A presents, as a common classification, criteria of three levels of cleanliness, and application
example for ductwork.
5.2 Assessment of the need for cleaning
Inspection of functionality and cleanliness of ventilation system is a part of proper maintenance of the
ventilation systems. Mostly the inspection of the cleanliness may arise from two purposes:
 to check if ventilation system is dirty and need to be cleaned (exceeding of a "target level");
 to evaluate cleanliness after the cleaning work (to control cleaning work).
The assessment methodology is presented in 6.2.
NOTE Annex A gives further recommendations on assessment frequency.
5.3 Selection of cleaning method
In the handing-over documents the cleaning methods shall be specified, and guidelines for reaching
the points to be cleaned shall also be given.
The cleaning method may vary according to the air distribution system. Normally dry methods are
enough in supply air systems and general extract air systems. Wet methods (or a combination of dry
and wet methods) may be needed for exhaust air ducts from professional kitchens and similar
installations where extract air contains smoke, grease and/or other similar impurities.
The instructions of all wet methods shall include a warning of conditions and restrictions of use, for
example that the method is only applicable only for ducts with high requirements of tightness and
smooth duct surfaces, and that the ducts need to be sloping to prevent retention of cleaning fluids in
the ducts.
A sufficient number of access doors shall be provided in the ductwork. Additionally special care shall
be taken during cleaning obstacles, such as dampers, sound attenuators etc., which are mounted in
the ducts. In many cases additional access doors are needed after or before such obstacle, which
then can be cleaned carefully. Requirements for location of and distance between access doors are
presented in EN 12097 and EN 13779.
5.4 Determination of cleaning interval
The cleaning interval shall be defined in the system documentation.
NOTE Further guidance can be found from REHVA and EVHA Guidelines and also from national guidelines,
e.g. VDI 6022 or HVCA.
5.5 Assessment of the result of cleaning
Methods for assessment of the need for cleaning can be also applied for assessment of the result of
cleaning.
6 Methodology
6.1 General methodology
Figure 1 presents a procedure to control and maintain cleanliness of ventilation system. It does not
include the design stages or selection and specification of the system, or any of its components.
The system shall be first checked visually, both in assessing the need for cleaning and in verification
of the result of cleaning. Objective measurements are needed if the visual inspection results in
disagreement or uncertainty about cleanliness or need for cleaning.
NOTE REHVA Guideline and some national guidelines like VDI 6022 and FiSIAQ Guideline give more
detailed guidance on product selection and specification from the hygienic point of view.

Figure 1 — Schematic flow chart for procedures to maintain cleanliness of ventilation system
If the components are certified for cleanliness or the cleanliness after production is otherwise verified,
and if the cleanliness instructions are properly documented, the commissioning may be reduced to
checking the documentation and spot checking of the system cleanliness (compliance with the
documentation).
The methods applied for objective measurements and verification needs to be consistent so that the
result of inspection is acceptable and gives reliable grounds for decision making to order cleaning
work of the system when needed. Verification after cleaning is needed for quality control of the
cleaning work, and to verify the cleaning result.
Objective methods are needed if any guidelines or demands on cleanliness are set in official or in
voluntary documents. The methods to evaluate the cleanliness vary, and thus target values given for
the cleaning action are not easy to compare. Certain visible signs like visible microbial growth are
enough to reveal the need for cleaning. For systems consisting dust with less potential health risks
the visible signs are not so clear and evaluation of the need by measurement may be needed to find
out whether the ventilation system should be cleaned or not.
6.2 Assessment of the need for cleaning
6.2.1 General
The assessment of cleanliness level of the system is important in order to define the cleaning method
to be used.
System components are considered to be polluted when visual inspection and analytic verification
give evidence of dust or microbial growth inside. Assessment will be carried out through inspection.
Dust accumulation, different types of pollutants, as well as “bacterial amplification”, should determine
the cleaning methods to be used and the environmental required controls.
Elements to be inspected for cleaning go from outdoor air intake and should be, at least, the following:
 Air handling units (AHU’s). AHU’s assessment should include all their components and sections:
fan section, filters, plenums, heating and cooling coils, condensate trays, sound attenuators, heat
recovery section, and humidifier section including droplet eliminators.
 Supply air ductwork, including all types of terminal devices and terminal units, sound attenuators,
duct-mounted heating and cooling coils, dampers and valves.
 Extract air ductwork, including all types of components.
6.2.2 Inspection plan
The inspection plan consists of the following information:
 review plan and reports;
 determining which systems will be inspected;
 determining where to inspect and sample (see note);
 choosing equipment and tools.
Additionally, the inspection plan describes the requirements of the specific qualification and
experience for inspectors before they are authorised to inspection work. The assessment frequency
shall be specified.
NOTE Recommendations for assessment frequency are given in Annex A. To obtain objective results a
representative number of samples from representative parts and sites in the ventilation system should be
selected for evaluation of the cleanliness of the whole system. A good rule of thumb for choosing sites or taking
samples is to select areas where the dust deposits are obvious, or liable to cause reduced IAQ. For inspecting
and sampling, the ventilation system can be divided in two parts, the ductwork and the rest of the system. Before
inspection or sampling, the sites should be selected at random with the aid of the design documents. The
sampling sites in the ductwork should be selected from the main duct starting from the AHU, main ducts, risers
and side branch ducts. The sampling sites should contain direct ducts and ducts with changes of direction or
terminations.
6.2.3 Evaluation methods of dust accumulation
Different methods to evaluate cleanliness of ventilation systems are applied. The simplest methods
are based on more or less subjective visual observation of the cleanliness of ventilation system
combined with use of some special instrumentation. The advanced techniques are able to give
relatively accurate results that are comparable to given limit values. In Figure 2 the methods are
presented in sequence of the reliability level of their results.

A
Key
A Reliability 3 Evaluation with optical gel tape
1 Vacuum sampling on filter, or wiping the dust with a cloth 4 Visual evaluation with reference scale
2 Gravimetric tape method 5 Visual survey without reference scale

Figure 2 — The reliability level of the results by different evaluations methods for dust
6.2.3.1 Visual inspection
Visual inspection method is a basic method to evaluate the cleanliness of ventilation system. Although
it is subjective as such it gives a very good estimate of the condition on ventilation system surfaces. It
is usually good enough to detect e.g. microbial growth on water reservoirs, and deposits from major
malfunction of filtration, and to reveal lack of maintenance. The visual inspection may be assisted with
technical devices such as cameras, endoscopes, and robotic cameras with video footages. In some
references, the visual inspection is developed more repeatable by using special forms and notebooks
that make the inspection more systematic. To make visual inspection more objective, besides the list
with dirtiness scales the inspectors should have experience from many ventilation systems. Visual
inspection need not to refer any mass values, preferably objective of the inspection (with the aid of
scale) should be the need of cleaning and other action for repairs. In clear cases visual inspection by
a trained person is also a useful method to evaluate cleanliness after the cleaning.
NOTE For new installations the visual inspection may be aided with a scale based on reference material
consisting photographs of newly installed ductworks. The scale presents the amount of dust accumulation on the
photographs so that the inspector is enabled to give a numeric value for evaluation.
6.2.3.2 Methods of verifying deposited solid dust and micro-organisms
Most of the methods to verify cleanliness of ventilation systems are based on the measurement of
mass of the dust and debris deposited on a known surface area. In the filter sampling method dust is
vacuumed on a weighed filter either without or with a filter housing. In the latter method, the dust
fastened on the walls of the filter housing is easily counted to the sample. Several methods are
developed for to loose the dust from the surface.
The sample is also possible to be taken without vacuuming by wiping method on the filter or non-
woven cloth. Solvent may strengthen the loosening of the dust from the surface, which makes the
method very effective especially for greasy solids.
A sticky tape is also used to collect deposited dust particles from the surface. The tape is weighed
before and after collection of the dust and the difference of the mass is used in calculation of the dust
density on the surface. The shape and dimensions of the tape restricts the sampling area constant.
On very dusty surfaces, the collection capacity of tape on surfaces with dusty surfaces rejects also the
usefulness of the method to obtain objective value.
A gel tape method is applicable for verif
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