EN 13384-1:2015

SLOVENSKI STANDARD
01-junij-2015
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SIST EN 13384-1:2003+A2:2008
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Chimneys - Thermal and fluid dynamic calculation methods - Part 1: Chimneys serving
one heating appliance
Abgasanlagen - Wärme- und strömungstechnische Berechnungsverfahren - Teil 1:
Abgasanlagen mit einer Feuerstätte
Conduits de fumée - Méthodes de calcul thermo-aéraulique - Partie 1: Conduits de
fumée ne desservant qu'un seul appareil
Ta slovenski standard je istoveten z: EN 13384-1:2015
ICS:
91.060.40 Dimniki, jaški, kanali Chimneys, shafts, ducts
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 13384-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2015
ICS 91.060.40 Supersedes EN 13384-1:2002+A2:2008
English Version
Chimneys - Thermal and fluid dynamic calculation methods -
Part 1: Chimneys serving one heating appliance
Conduits de fumée - Méthodes de calcul thermo-aéraulique Abgasanlagen - Wärme- und strömungstechnische
- Partie 1: Conduits de fumée ne desservant qu'un seul Berechnungsverfahren - Teil 1: Abgasanlagen mit einer
appareil Feuerstätte
This European Standard was approved by CEN on 24 January 2015.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.

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

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13384-1:2015 E
worldwide for CEN national Members.

Contents Page
Foreword .5
1 Scope .6
2 Normative references .6
3 Terms and definitions .6
4 Symbols and abbreviations . 10
5 Calculation method for non-balanced flue chimneys . 14
5.1 General principles. 14
5.2 Pressure requirements . 15
5.2.1 Negative pressure chimneys . 15
5.2.2 Positive pressure chimneys . 16
5.3 Temperature requirement . 16
5.4 Calculation procedure . 17
5.5 Flue gas data characterising the heating appliance . 18
5.5.1 General . 18
5.5.2 Flue gas mass flow . 18
5.5.3 Flue gas temperature . 19
5.5.4 Minimum draught for the heating appliance (P ) for negative pressure chimney . 19
W
5.5.5 Maximum draught for the heating appliance (P ) for negative pressure chimney . 20
Wmax
5.5.6 Maximum differential pressure of the heating appliance (P ) for positive pressure
WO
chimney . 20
5.5.7 Minimum differential pressure of the heating appliance (P ) for positive pressure
WOmin
chimney . 20
5.6 Characteristic data for the calculation . 20
5.6.1 General . 20
5.6.2 Mean value for roughness (r) . 20
5.6.3 Thermal resistance (1/Λ) . 20
5.7 Basic values for the calculation . 21
5.7.1 Air temperatures . 21
5.7.2 External air pressure (p ) . 23
L
5.7.3 Gas constant . 23
5.7.4 Density of the external air (ρ ) . 24
L
5.7.5 Specific heat capacity of the flue gas (c ) . 24
p
5.7.6 Condensing temperature (T ) . 24
sp
5.7.7 Correction factor for temperature instability (S ) . 24
H
5.7.8 Flow safety coefficient (S ) . 24
E
5.8 Determination of the temperatures . 25
5.8.1 General . 25
5.8.2 Calculation of the coefficient of cooling (K) . 25
5.8.3 Coefficient of heat transmission (k ) . 26
b
5.9 Determination of the density of the flue gas and the velocity of the flue gas . 28
5.9.1 Density of the flue gas (ρ ) . 28
m
5.9.2 Velocity of the flue gas (w ) . 28
m
5.10 Determination of the pressures . 29
5.10.1 Pressure at the flue gas inlet into the chimney . 29
5.10.2 Theoretical draught available due to chimney effect (P ) . 30
H
5.10.3 Pressure resistance of the chimney (P ) . 30
R
5.10.4 Wind velocity pressure (P ) . 31
L
5.11 Minimum draught required at the flue gas inlet into the chimney and maximum allowed
and P ) and maximum and minimum differential pressure at the flue gas
draught (P
Ze Zemax
and P ) . 32
inlet into the chimney (P
ZOe ZOemin
5.11.1 General . 32
5.11.2 Minimum and maximum draught for the heating appliance (P and P ) and maximum
W Wmax
and P ) . 33
and minimum differential pressure of the heating appliance (P
WO WOmin
5.11.3 Effective pressure resistance of the connecting flue pipe (P ) . 33
FV
5.11.4 Pressure resistance of the air supply (P ) . 34
B
5.12 Calculation of the inner wall temperature at the chimney outlet (T ) . 35
iob
6 Secondary air for negative pressure chimneys . 37
6.1 General . 37
6.2 Calculation method . 37
6.3 Basic values for the calculation of secondary air . 37
6.3.1 General . 37
6.3.2 Mixing calculations . 37
6.4 Pressures . 38
6.4.1 Pressure resistance for the air supply with secondary air (P ) . 38
BNL
6.4.2 Draught required for the secondary air devices (P ) . 39
NL
6.4.3 Pressure resistance for that part of the connecting flue pipe before the secondary air
) . 40
device (P
FV1
6.4.4 Pressure requirement with secondary air . 41
6.5 Temperature requirement with secondary air . 41
7 Calculation method for balanced flue chimneys . 41
7.1 General principles . 41
7.2 Pressure requirements . 42
7.3 Temperature requirements . 43
7.4 Calculation procedure . 43
7.5 Flue gas data characterizing the heating appliance . 43
7.6 Characteristic data for the calculation . 44
7.7 Basic values for the calculation . 44
7.7.1 Air temperatures . 44
7.7.2 Other basic values . 45
7.8 Determination of the temperatures . 45
7.8.1 Non-concentric (separate) ducts . 45
7.8.2 Concentric ducts – calculation based on a correction factor for heat radiation . 45
7.8.3 Concentric ducts – calculation based on calculated heat radiation . 60
7.8.4 Mean temperatures for pressure calculation. 64
7.9 Determination of densities and velocities . 65
7.9.1 Density and velocity of the flue gas . 65
7.9.2 Density and velocity of the supply air . 65
7.10 Determination of pressures . 66
7.10.1 Pressure at the flue gas inlet into the chimney . 66
7.10.2 Theoretical draught due to chimney effect in the chimney segment (P ) . 66
H
7.10.3 Pressure resistance in the chimney segment (P ) . 66
R
7.10.4 Wind velocity pressure (P ) . 66
L
7.11 Minimum draught required at the flue gas inlet into the chimney and maximum allowed
and P ) and maximum and minimum differential pressure at the flue gas
draught (P
Ze Zemax
and P ) . 66
inlet into the chimney (P
ZOe ZOemin
7.11.1 General . 66
7.11.2 Minimum and maximum draught for the heating appliance (P and P ) and maximum
W Wmax
and P ) . 67
and minimum differential pressure of the heating appliance (P
WO WOmin
7.11.3 Effective pressure resistance of the connection pipe (P ) . 67
FV
7.11.4 Pressure resistance of the air supply . 67
7.12 Calculation of the inner wall temperature at the chimney outlet (T ) . 70
iob
8 Consideration of the condensation heat of the flue gas water vapour . 70
8.1 General . 70
8.2 Onset of condensation . 71
8.3 Calculation of the flue gas temperature at the outlet of a chimney segment with

condensation (j ≥ NsegK) . 73
9 Consideration of chimney fans . 78
9.1 General . 78
9.2 Inline fans . 79
9.3 Exhaust fans . 80
Annex A (informative) Calculation of thermal resistance . 82
Annex B (informative) Tables . 83
Annex C (informative) Chimney outlet with regard to adjacent buildings . 98
Annex D (informative) Determination of the gas constant R considering the condensation . 99

Foreword
This document (EN 13384-1:2015) has been prepared by Technical Committee CEN/TC 166 “Chimneys”, the
secretariat of which is held by ASI.
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 October 2015, and conflicting national standards shall be withdrawn at
the latest by October 2015.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 13384-1:2002+A2:2008.
According to EN 13384-1:2002+A2:2008 the following fundamental changes are given:
— editorial mistakes have been corrected;
— mistakes in formulas have been corrected;
— for wood the rise of the dew point to take into account the acid condensation has been deleted;
— table for material characteristics in Table B.5 has been adapted to EN 15287-1 and supplemented by
radiation coefficients;
— in Calculation of thermal resistance according to Annex A are linked to the method of EN 15287-1 for
taking into account the temperature dependence has been added;
— for non-concentric ducts the calculation of the mean temperature of the air supply has been amended;
— for chimney fans a calculation procedure has been added;
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
This European Standard “Chimneys — Thermal and fluid dynamic calculation methods” consists of three
Parts:
— Part 1: Chimneys serving one heating appliance
— Part 2: Chimneys serving more than one heating appliance
— Part 3: Methods for the development of diagrams and tables for chimneys serving one heating appliance
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, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
1 Scope
This European Standard specifies methods for the calculation of the thermal and fluid dynamic characteristics
of chimneys serving one heating appliance.
The methods in this part of this European Standard are applicable to negative or positive pressure chimneys
with wet or dry operating conditions. It is valid for chimneys with heating appliances for fuels subject to the
knowledge of the flue gas characteristics which are needed for the calculation.
The methods in this part of this European Standard are applicable to chimneys with one inlet connected with
one appliance. The methods in Part 2 of this European Standard are applicable to chimneys with multiple
inlets and one inlet with multiple appliances. Part 3 describes methods for the development of diagrams and
tables for chimneys serving one heating appliance.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN 1443, Chimneys - General requirements
EN 1856-1, Chimneys - Requirements for metal chimneys - Part 1: System chimney products
EN 1859, Chimneys — Metal chimneys — Test methods
EN 13502, Chimneys - Requirements and test methods for clay/ceramic flue terminals
EN 15287-1:2007+A1:2010, Chimneys - Design, installation and commissioning of chimneys - Part 1:
Chimneys for non-roomsealed heating appliances
prEN 16475-2, Chimneys - Accessories - Part 2: Chimney fans - Requirements and test methods
CEN/TR 1749, European scheme for the classification of gas appliances according to the method of
evacuation of the combustion products (types)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1443 and the following apply.
3.1
heat output
Q
amount of heat produced by a heating appliance per unit of time
3.1.1
nominal heat output
Q
N
continuous heat output specified by the manufacturer of the heating appliance related to specified fuels
3.1.2
heat output range
range of output below the nominal heat output specified by the manufacturer over which the appliance can be
used
3.2
heat input
Q
F
amount of heat in unit time which is supplied to the heating appliance by the fuel based on its net caloric value
H
u
3.3
efficiency of the heating appliance
η
W
ratio of the heat output (Q) from the appliance to the heat input (Q )
F
3.4
flue gas mass flow
m
mass of flue gas leaving the heating appliance through the connecting flue pipe per time unit
3.5
effective height of the chimney
H
difference in height between the axis of the flue gas inlet into the chimney and the outlet of the chimney
3.6
effective height of the connecting flue pipe
H
V
difference in height between the axis of the flue gas chimney outlet of the heating appliance and the axis of
the flue gas inlet into the chimney
Note 1 to entry In the case of open fire chimneys, H is the difference in height between the height of the upper frame
V
of the furnace and the axis of the flue gas inlet into the chimney.
3.7
draught
positive value of the negative pressure in the flue
3.8
theoretical draught available due to chimney effect
P
H
pressure difference caused by the difference in weight between the column of air equal to the effective height
outside a chimney and the column of flue gas equal to the effective height inside the chimney
3.9
pressure resistance of the chimney
P
R
pressure which is necessary to overcome the resistance of the flue gas mass flow which exists when carrying
the flue gases through the chimney
3.10
wind velocity pressure
P
L
pressure generated on the chimney due to wind
3.11
minimum draught at the flue gas inlet into the chimney

P
Z
difference between the minimum theoretical draught and the sum of the maximum pressure resistance of the
chimney and the wind velocity pressure
3.12
maximum draught at the flue gas inlet into the chimney
P
Zmax
difference between the maximum theoretical draught and the minimum pressure resistance in the chimney
3.13
minimum draught for the heating appliance
P
W
difference between the static air pressure of the room of installation of the heating appliance and the static
pressure of the flue gas at the chimney outlet of the appliance which is necessary to maintain the correct
operation of the heating appliance
3.14
maximum draught for the heating appliance

P
Wmax
difference between the static air pressure of the room of installation of the heating appliance and the static
pressure of the flue gas at the outlet of the appliance which is the maximum allowed to maintain the correct
operation of the heating appliance
3.15
effective pressure resistance of the connecting flue pipe
P
FV
static pressure difference between the axis of the inlet of the connecting flue pipe and the axis of the chimney
outlet due to the theoretical draught and pressure resistance
3.16
effective pressure resistance of the air supply
P
B
difference between the static pressure in the open air and the static air pressure in the room of installation of
the heating appliance at the same height
3.17
minimum draught required at the flue gas inlet into the chimney
P
Ze
sum of the minimum draught required for the heating appliance and the draught required to overcome the
effective pressure resistance of the connecting flue pipe and the effective pressure resistance of the air supply
3.18
maximum allowed draught at the flue gas inlet into the chimney
P
Zemax
sum of the maximum draught allowed for the heating appliance and the draught required to overcome the
effective pressure resistance of the connecting flue pipe and the effective pressure resistance of the air supply
3.19
maximum positive pressure at the flue gas inlet into the chimney
P
ZO
difference of the maximum pressure resistance and the minimum theoretical draught of the chimney added by
the wind velocity pressure
3.20
minimum positive pressure at the flue gas inlet into the chimney

P
ZOmin
difference of the minimum pressure resistance and the maximum theoretical draught of the chimney
3.21
maximum differential pressure of the heating appliance
P
WO
maximum difference between the static pressure of the flue gas at the chimney outlet of the appliance and the
static pressure of the air at the inlet to the heating appliance specified for its correct operation
3.22
minimum differential pressure of the heating appliance
P
WOmin
minimum difference between the static pressure of the flue gas at the outlet of the appliance and the static
pressure of the air at the inlet to the heating appliance specified for its correct operation. This can be a
negative value.
3.23
maximum differential pressure at the flue gas inlet into the chimney

P
ZOe
difference between the maximum differential pressure of the heating appliance and the sum of the effective
pressure resistance of the connecting flue pipe and the effective pressure resistance of the air supply
3.24
secondary air
ambient air added to the flue gas in addition to the nominal flue gas mass flow
3.25
minimum differential pressure at the flue gas inlet into the chimney
P
ZOemin
difference between the minimum differential pressure of the heating appliance and the sum of the effective
pressure resistance of the connecting flue pipe and the effective pressure resistance of the air supply
3.26
secondary air device
draught regulator or a draught diverter
3.27
draught regulator
component which automatically supplies ambient air to the chimney, the connecting flue pipe or the heating
appliance
3.28
draught diverter
device, placed in the combustion products passage of the heating appliance, that is intended to maintain the
quality of combustion within certain limits and to keep the combustion stable under certain conditions of up
draught and down draught
3.29
temperature limit of the inner wall
T
g
allowed minimum temperature of the inner wall of the chimney outlet
3.30
air-supply duct
component or components parallel to the chimney (separate or concentric) that conveys combustion air from
the outside atmosphere to the inlet of the connecting air supply pipe
3.31
balanced flue chimney
chimney where the point of air entry to the air supply duct is adjacent to the point of discharge of combustion
products from the flue, the inlet and outlet being so positioned that wind effects are substantially balanced
3.32
chimney segment
calculation part of a chimney
3.33
condensate mass flow
Dm
D
mass of water vapour of the flue gas condensed in the heating appliance, connecting flue pipe or the chimney
per time unit
3.34
connecting air supply pipe
component or components connecting the air supply duct outlet with the room-sealed heating appliance
combustion air inlet
3.35
condensation factor
f
K
proportion of the theoretical maximum condensation mass flow usable in the calculation
3.36
chimney fan
exhaust fan or inline fan
3.36.1
exhaust fan
fan positioned on the outlet of the chimney
3.36.2
inline fan
fan positioned as a section of the connecting flue
4 Symbols and abbreviations
The symbols given in this clause can be completed by one or more indices to indicate location or materials if
necessary.
Table 1 — Symbols, terminology and units
Symbol Terminology Unit
A cross section area m
c specific heat capacity J/(kg · K)
c specific heat capacity of flue gas J/(kg · K)
p
d thickness of the section m
D diameter m
D hydraulic diameter m
h
E heat flux ratio –
g acceleration due to gravity m/s
H effective height of the chimney m
k coefficient for heat transmission W/(m · K)
K coefficient of cooling –
L length m
l proportion of condensation surface –
C
flue gas mass flow kg/s

m
flue gas mass flow of heating appliance reduced by condensed water kg/s
m
W
condensate mass flow kg/s

m
D
N Nusselt number –
u
N number of segments –
seg
p
static pressure Pa
p
external air pressure Pa
L
P
effective pressure resistance of the air supply Pa
B
P
pressure resistance due to friction and form resistance of the chimney Pa
E
P effective pressure resistance of the connecting flue pipe Pa
FV
P difference in pressure caused by change of velocity of flue gas in the Pa
G
chimney
P theoretical draught available due to chimney effect Pa
H
P theoretical draught available due to chimney effect of the connecting flue Pa
HV
pipe
P wind velocity pressure Pa
L
P draught required for secondary air devices Pa
NL
P pressure resistance of the chimney Pa
R
P pressure resistance of the connecting flue pipe Pa
RV
P minimum draught for the heating appliance Pa
W
P maximum draught for the heating appliance Pa
Wmax
P maximum differential pressure of the heating appliance Pa
WO
P minimum differential pressure of the heating appliance Pa
WOmin
P minimum draught at the flue gas inlet into the chimney Pa
Z
P
maximum draught at the flue gas inlet into the chimney Pa
Zmax
P
minimum draught required at the flue gas inlet into the chimney Pa
Ze
P
maximum allowed draught at the flue gas inlet into the chimney Pa
Zemax
P maximum positive pressure at the flue gas inlet into the chimney Pa
ZO
P minimum positive pressure at the flue gas inlet into the chimney Pa
ZOmin
P maximum differential pressure at the flue gas inlet into the chimney Pa
ZOe
P minimum differential pressure at the flue gas inlet into the chimney Pa
ZOemin
P maximum allowed pressure from the designation of the chimney Pa
Zexcess
P maximum allowed pressure from the designation of the connecting flue Pa
ZVexcess
pipe
Pr Prandtl number –
q heat transfer from the flue to the outer surface W
C
q condensation heat W
K
Q heat output kW
Q heat input kW
F
QN
nominal heat output kW
r
mean value for roughness of the inner wall m
R
gas constant of the flue gas J/(kg · K)
R
gas constant of the air J/(kg · K)
L
Re
Reynolds number –
s cross section m
S flow safety coefficient –
E
S correction factor for temperature instability –
H
S correction factor for radiation –
rad
t
temperature °C
T
temperature, absolute K
T temperature limit K
g
T inner wall temperature at chimney outlet K
io
T inner wall temperature at the chimney outlet at temperature equilibrium K
iob
T flue gas temperature immediately before the additional insulation K
irb
T external air temperature K
L
T mean temperature of the flue gas K
m
T water dew point K
p
T condensing temperature K
sp
T ambient air temperature K
u
T ambient air temperature of the boiler room K
ub
T ambient air temperature for heated areas K
uh
T ambient air temperature for areas external to the building K
ul
T
ambient air temperature at the chimney outlet K
uo
T
is the ambient air temperature immediately before the additional insulation K
ur
T
ambient air temperature for unheated areas inside the house K
uu
T flue gas temperature of the appliance K
W
T flue gas temperature of the appliance at nominal heat output K
WN
T flue gas temperature of the appliance at the lowest possible heat output K
Wmin
U internal chimney segment parameter m
w mean velocity within a cross section m/s
w mean velocity over a defined length m/s
m
y form value –
z height above sea level m
α coefficient of heat transfer W/(m · K)
β ratio of the combustion air mass flow to the flue gas mass flow –
γ angle between flow directions °
δ wall thickness m
ε proportion of black body radiation emitted by a surface –
ζ coefficient of flow resistance due to a directional and/or –
cross sectional and/or mass flow change in the flue
η dynamic viscosity
N ⋅ s/m
η efficiency of the heating appliance –
W
η efficiency of the heating appliance at nominal heat output –
WN
λ coefficient of thermal conductivity W/(m · K)
ρ density kg/m
ρ density of the external air kg/m

L
ρ mean density of flue gas averaged over a defined length and over the kg/m
m
cross section
σ (CO ) volume-concentration of CO %
2 2
σ (H O) volume-concentration of H O (vapour) %
2 2
2 4
σ black body radiation number W/(m · K )
Rad
ψ coefficient of flow resistance due to friction of the flue –
thermal resistance m · K/W


Λ

Table 2 — Additional subscripts
Subscript Terminology Unit
a outside –
A flue gas –
b equilibrium temperature condition –
B combustion air –
D water vapour –
e entrance –
F open fire place –
G change in velocity –
i inside –
K condensation –
L open air (outside) –
m mean value –
M mixture –
n counting index –
N nominal value –
NL secondary air –
o chimney outlet –
O positive pressure –
tot totalized over all sections (segments) –
u ambient air –
V connecting flue pipe –
W heating appliance –
5 Calculation method for non-balanced flue chimneys
5.1 General principles
The calculation of inside dimensions (cross section) of negative pressure chimneys is based on the following
four criteria:
— the minimum draught at the flue gas inlet into the chimney shall be equal to or greater than the minimum
draught required at the flue gas inlet into the chimney;
— the minimum draught at the flue gas inlet to the chimney shall be equal to or greater than the effective
pressure resistance of the air supply;
— the maximum draught at the flue gas inlet into the chimney shall be equal to or less than the maximum
allowed draught at the flue gas inlet into the chimney;
— the temperature of the inner wall at the outlet of the chimney shall be equal to or greater than the
temperature limit.
The calculation of inside dimensions (cross section) of positive pressure is based on the following four criteria:
— the maximum positive pressure at the flue gas inlet into the chimney shall be equal or less than the
maximum differential pressure at the flue gas inlet into the chimney;
— the maximum positive pressure in the connecting flue pipe and in the chimney shall not be higher than the
excess pressure for which both are designated;
— the minimum positive pressure at the flue gas inlet into the chimney shall be equal or greater than the
minimum differential pressure at the flue gas inlet into the chimney;
— the temperature of the inner wall at the chimney outlet of the chimney shall be equal to greater than the
temperature limit.
NOTE The pressure requirements for maximum draught or minimum positive pressure are only required if there is a
limit for the maximum draught for the negative pressure heating appliance or a minimum differential pressure of the
positive pressure heating appliance.
In order to verify the criteria two sets of external conditions are used:
— the calculation of the minimum draught and maximum positive pressure is made with conditions for which
the capacity of the chimney is minimal (i.e. high outside temperature); and also
— the calculation of the maximum draught and minimum positive pressure and of the inner wall temperature
with conditions for which the inside temperature of the chimney is minimal (i.e. low outside temperature.
5.2 Pressure requirements
5.2.1 Negative pressure chimneys
The following relationships shall be verified:
P = P − P − P ≥ P + P + P = P , in Pa (1)
Z H R L W FV B Ze
P ≥ P , in Pa (2)
Z B
and if appropriate
P = P − P ≤ P + P + P = P , in Pa (2a)
Zmax H R Wmax FV B Ze max
where
P
is the effective pressure resistance of air supply (see 5.11.3), in Pa;
B
P is the effective pressure resistance of the connecting flue pipe, in Pa;
FV
P
is the theoretical draught available due to chimney effect, in Pa;
H
P is the wind velocity pressure, in Pa;
L
P
is the pressure resistance of the chimney, in Pa;
R
P is the minimum draught for the heating appliance, in Pa;
W
P is the maximum draught for the heating appliance, in Pa;
Wmax
P is the minimum draught at the flue gas inlet into the chimney (see 5.10), in Pa;
Z
P is the maximum draught at the flue gas inlet into the chimney (see 5.11), in Pa;
Zmax
P is the minimum draught required at the flue gas inlet into the chimney, in Pa;
Ze
P is the maximum allowed draught at the flue gas inlet into the chimney, in Pa.
Zemax
NOTE The values of P and P in Formulas (1) and (2a) are normally different because the conditions are different.
H H
5.2.2 Positive pressure chimneys
The following relationships shall be verified:
P = P - P + P ≤ P - P - P = P , in Pa (3)
ZO R H L WO B FV Zoe
P ≤ P , in Pa (4)
ZO Z excess
P + P ≤ P , in Pa (5)
ZO FV ZV excess
and if appropiate
P = P - P ≥ P - P - P = P , in Pa (5a)
ZOmin R H WOmin B FV Zoemin
where
P is the effective pressure resistance of air supply, in Pa;
B
P
is the effective pressure resistance of the connecting flue pipe, in Pa;
FV
P is the theoretical draught available due to chimney effect, in Pa;
H
P is the wind velocity pressure, in Pa;
L
P is the pressure resistance of the chimney, in Pa;
R
P is the maximum differential pressure of the heating appliance, in Pa;
WO
P is the minimum differential pressure of the heating appliance, in Pa;
WOmin
P is the maximum positive pressure at the flue gas inlet into the chimney, in Pa;
ZO
P is the minimum positive pressure at the flue gas inlet into the chimney, in Pa;
ZOmin
P is the maximum differential pressure at the flue gas inlet into the chimney, in Pa;
ZOe
P is the minimum differential pressure at the flue gas inlet into the chimney, in Pa;
ZOemin
P is the maximum allowed pressure from the designation of the chimney, in Pa;
Z excess
P is the maximum allowed pressure from the designation of the connecting flue pipe, in Pa.
ZVexcess
NOTE The values of PH and PR in Formulas (3) and (5a) are normally different because the conditions are different
5.3 Temperature requirement
The following relationship shall be verified:
TT≥ , in K (6)
iob g
where
T is the inner wall temperature at the chimney outlet at temperature equilibrium, in K;
i
ob
T is the temperature limit, in K.
ig
If the chimney above the roof has additional insulation the following relationship shall also be verified:
TT≥ , in K (7)
irb g
where
T is the inner wall temperature immediately before the additional insulation, in K.
i
irb
The temperature limit T of chimneys with dry operating conditions shall be taken as the condensing
ig
temperature T of the flue gas (see 5.7.6).
isp
The temperature limits T of chimneys with wet operating conditions shall be taken as 273,15 K which
ig
prevents the formation of ice at the chimney outlet.
NOTE The comparison of the inner wall temperature before the additional insulation T with the admissible limit
iirb
temperature of the flue gas T is not necessary, if the value of the thermal resistance of the additional insulation is not
g
i
more than 0,1 (m ⋅ K)/W. For chimneys operating under wet conditions the comparison is not necessary, if the value of
the ambient air temperature immediately before the additional insulation is ≥ 0 °C.
5.4 Calculation procedure
For the calculation of the pressure and temperature values for the relationships of Formulas (1), (2), (2a), (3),
(4), (5), (5a) and (6) the values of the flue gas data characterising according to 5.5 shall be obtained for the
appliance. The data specified in 5.6 shall be obtained for the chimney and its connecting flue pipe. For new
built chimneys, a pre-estimated value for the flue size should be used.
5.7 to 5.11 provide calculations needed to finalise the chimney thermal and fluid dynamic calculations. In 5.7
the formulas provide the calculation of the basic data which are needed for further calculation.
In 5.5.3 and 5.8 the formulas for the calculations of the relevant temperatures are compiled. The formulas for
the density of the flue gas and its velocity are compiled in 5.9.
The procedure in 5.10 and 5.11 shall be used to validate the pressure requirement.
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