SIST EN 14114:2002
(Main)Hygrothermal performance of building equipment and industrial installations - Calculation of water vapour diffusion - Cold pipe insulation systems
Hygrothermal performance of building equipment and industrial installations - Calculation of water vapour diffusion - Cold pipe insulation systems
This standard specifies a method to calculate the density of water vapour flow rate for cold pipes, and the total amount of water absorption over time. This calculation method applies only when the water vapour partial pressure difference is perpendicular to the axis of the pipes and the water vapour partial pressure is constant at all points equidistant from the axis of the pipe.
Wärme- und feuchtetechnisches Verhalten von haus- und betriebstechnischen Anlagen - Berechnung der Wasserdampfdiffusion - Dämmung von Kälteleitungen
Diese Norm beschreibt Verfahren zur Berechnung der Wasserdampf-Diffusionsstromdichte für kälteleitungen und der Gesamtmenge an Wasserabsorption über die Zeit. Dieses Berechnungsverfahren gilt nur, wenn die Wasserdampfteildruckdifferenz senkrecht zur Rohrachse auftritt und der Wasserdampfteildruck an allen Punkten, die von der Rohrachse einen gleichen Abstand haben, konstant ist.
Performance hygrothermique des équipements de bâtiments et installations industrielles - Calcul de la diffusion de vapeur d'eau - Systemes d'isolation de tuyauteries froides
La présente norme donne une méthode permettant de calculer la densité du flux de vapeur deau dans le cas des tuyauteries froides ainsi que la quantité totale d'eau absorbée en fonction du temps. Cette méthode de calcul ne s'applique que lorsque la différence de pression partielle de vapeur d'eau est perpendiculaire a l'axe du tuyau et que la pression partielle de vapeur d'eau est constante en tout point équidistant de l'axe du tuyau.
Higrotermalno obnašanje opreme stavb in industrijskih inštalacij - Izračun difuzije vodne pare - Sistemi za izoliranje hladnih cevi
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Wärme- und feuchtetechnisches Verhalten von haus- und betriebstechnischen Anlagen - Berechnung der Wasserdampfdiffusion - Dämmung von KälteleitungenPerformance hygrothermique des équipements de bâtiments et installations industrielles - Calcul de la diffusion de vapeur d'eau - Systemes d'isolation de tuyauteries froidesHygrothermal performance of building equipment and industrial installations - Calculation of water vapour diffusion - Cold pipe insulation systems91.120.10Toplotna izolacija stavbThermal insulationICS:Ta slovenski standard je istoveten z:EN 14114:2002SIST EN 14114:2002en01-november-2002SIST EN 14114:2002SLOVENSKI
STANDARD
SIST EN 14114:2002
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 14114March 2002ICS 91.120.10English versionHygrothermal performance of building equipment and industrialinstallations - Calculation of water vapour diffusion - Cold pipeinsulation systemsPerformance hygrothermique des équipements debâtiments et installations industrielles - Calcul de ladiffusion de vapeur d'eau - Systèmes d'isolation detuyauteries froidesWärme- und feuchtetechnisches Verhalten von haus- undbetriebstechnischen Anlagen - Berechnung derWasserdampfdiffusion - Dämmung von KälteleitungenThis European Standard was approved by CEN on 28 June 2001.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2002 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14114:2002 ESIST EN 14114:2002
EN 14114:2002 (E)2ContentsPageForeword3Introduction41 Scope42 Normative references53 Terms, definitions, symbols and units54 Calculation equations75 Boundary conditions96 Calculation procedure10Annex A (informative)
Examples14Annex B (informative)
Experimental determination of the evaporation rate from the surfaceof a wet wick fabric16Bibliography18SIST EN 14114:2002
EN 14114:2002 (E)3ForewordThis document (EN 10264-1:2002) has been prepared by Technical Committee CEN/TC 89"Thermal performance of buildings and building components"", the secretariat of which isheld by SIS.This European Standard shall be given the status of a national standard, either by publicationof an identical text or by endorsement, at the latest by September 2002, and conflictingnational standards shall be withdrawn at the latest by September 2002.The enquiry version was designated prEN ISO 15758. However, as a result of the enquiry,ISO decided to decouple from the Vienna Agreement; CEN and ISO will proceed topublication on their own.This standard is one of a series of standards which specify calculation methods for the designand evaluation of the thermal and moisture related performance properties of buildings andbuilding components.The Annexes A and B are informative.According to the CEN/CENELEC Internal Regulations, the national standards organizationsof the following countries are bound to implement this European Standard: Austria, Belgium,Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and theUnited Kingdom.SIST EN 14114:2002
EN 14114:2002 (E)4IntroductionIf the thermal insulation of a cold pipe system is not completely water vapour tight, there willbe a flow of water vapour from the warm environment to the surface of the pipe, whenever thetemperature of the surface of the cold pipe is below the dew point of the ambient air.
Thisflow of water vapour leads to an interstitial condensation in the insulation layer and/or dewformation on the surface of the pipe itself.
Interstitial condensation may cause the insulationmaterial to deteriorate and dew formation on the surface of a metal pipe may cause corrosionover time.
If the temperature is below 0 C ice will be formed and the methods of thisstandard will not apply.In periods where the dew point of the ambient air is higher than the temperature of the outersurface of the insulation surface condensation will occur.
This is dealt with in EN ISO 12241.Different measures are available to control water vapour transfer and reduce the amount ofcondensation.
The following are normally applied:a) Installation of a vapour retarder;b) Use of insulation materials with a high water vapour resistance factor (low permeability);c) Use of a vapour retarder and a capillary active fabric to continuously remove condensedwater from the pipe surface to the environment.Which protection measure is chosen depends on the ambient climate, the temperature of themedium in the pipe and the water vapour diffusion resistance of the insulation layer.
Thesuccess of any system is strongly dependent on workmanship and maintenance.
In any caseanti-corrosion measures should be applied to a metal pipe in severe conditions.The expected economic lifetime of an insulation system, assuming a maximum acceptableaccumulated moisture content, can be calculated using the methods in this standard.1 ScopeThis standard specifies a method to calculate the density of water vapour flow rate in cold pipeinsulation systems, and the total amount of water diffused into the insulation over time.
Thiscalculation method presupposes that water vapour can only migrate into the insulation system bydiffusion, with no contribution from airflow.
It also assumes the use of homogeneous, isotropicinsulation materials so that the water vapour partial pressure is constant at all points equidistantfrom the axis of the pipe.The standard is applicable when the temperature of the medium in the pipe is above 0 C. Itapplies to pipes inside buildings as well as in the open air.SIST EN 14114:2002
EN 14114:2002 (E)52 Normative referencesThis European Standard incorporates by dated or undated reference, provisions from otherpublications. These normative references are cited at the appropriate places in the text and thepublications 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 byamendment or revision. For undated references the latest edition of the publication referred toapplies (including amendments).EN ISO 9346Thermal insulation - Mass transfer - Physical quantities and definitions(ISO 9346:1987)EN ISO 12241Thermal insulation for building equipment and industrial installations -Calculation rules (ISO 12241:1998)EN ISO 12572Hygrothermal performance of building materials and products -Determination of water vapour transmission properties(ISO 12572:2001)EN ISO 13788Hygrothermal performance of building components and buildingelements - Internal surface temperature to avoid critical surface humidityand interstitial condensation – Calculation methods (ISO 13788:2001)3Terms, definitions, symbols and units3.1 Terms and definitionsFor the purposes of this standard, the terms and definitions given in EN ISO 9346, EN ISO 12572,EN ISO 13788 and the following apply.3.1.1exposed moist areasurface area of a capillary active fabric that is exposed to the ambient atmosphere3.1.2vapour retardermaterial with high resistance to the flow of water vapour3.1.3corrected water vapour diffusion equivalent air layer thicknessthickness of an imaginary plane layer with
=1, and an area of
Dj which has the samediffusion resistance as the layer j with
= jNOTE
See Equation (18).SIST EN 14114:2002
EN 14114:2002 (E)63.2 Symbols and unitsSymbolQuantityUnitAesurface area from which evaporation takes place per linearmetre of the pipem2/mDjoutside diameter of jth layer of an insulation systemmD0outside diameter of cold pipemGtotal moisture uptake over a period per linear metre of pipekg/mPactual atmospheric pressurePaP0standard atmospheric pressure = 101325PaRvgas constant for water vapour
= 461,5J/(kgK)Tthermodynamic temperatureKZPwater vapour resistance of insulation system per linear metreof pipemsPa/kgZjwater vapour resistance of jth layer of an insulation system perlinear metre of pipemsPa/kgZf1water vapour resistance of one thin foil, cladding or skin perlinear metre of pipe.msPa/kgdthickness of an insulation layermfeevaporation factorkg/(m2sPa)gwater vapour flow rate within the insulation per linear metreof pipekg/(ms)gcrate of condensation per linear metre of pipekg/(m·s)geevaporation rate per linear metre of pipekg/(ms)hcconvection heat transfer coefficientW/(m2·K)ppartial water vapour pressurePapapartial water vapour pressure of airPapsatsaturated water vapour pressurePasdwater vapour diffusion equivalent air layer thicknessmsdfwater vapour diffusion equivalent air layer thickness of foilsmtperiod of calculation (month or year)month, yearxdistancemwater vapour permeabilitykg/(msPa)0water vapour permeability of airkg/(msPa)water vapour resistance factor-d,jcorrected water vapour diffusion equivalent air layer thicknessof layer jmjd,~total corrected water vapour diffusion equivalent air layerthickness from surface of cold pipe to the outside of layer jm0temperature of the medium in the pipeCNOTE
For practical reasons, hours or days are often used instead of seconds as time units.SIST EN 14114:2002
EN 14114:2002 (E)74 Calculation equations4.1 GeneralThe density of water vapour flow rate, g, through a material is calculated by the followingequation:xpgdd(1)where
is the water vapour permeability of the material.The total moisture uptake during a period, G, is given by:tgGtd0(2)In calculations the diffusion resistance factor, , is commonly used instead of the permeability0(3)where 0 is the water vapour permeability of still air, which can be calculated from:81,1v00273083,0TPTRP(4)For approximate calculations, 0 can be assumed to be constant in the temperature range underconsideration; the following value can therefore be used:0 = 2,0
10-10(5)4.2 Homogeneous insulationIn the case of a cold pipe with a single homogeneous layer of insulation, the density of watervapour flow per metre of an insulated cold pipe is given by replacing the differentialexpression by the vapour pressure difference in Equation (1):P0sata)(Zppg(6)wherepa is the vapour pressure of the ambient air, in Pa;psat(0) is the saturation vapour pressure at the outside surface of the pipe, in Pa;ZP
is the water vapour resistance per linear metre of the pipe insulation, inmsPa/kg, defined by Equation (7):SIST EN 14114:2002
EN 14114:2002 (E)82ln01PDDZ(7)There will only be a vapour flow and hence condensation at the surface of the cold pipe whenthe vapour pressure of the ambient air is higher than the saturation vapour pressure at the coldsurface of the pipe.The total water uptake over a period t is then given by:ttZtptpG0P0satad))(()((8)4.3 Multi-layer insulation systemsThe water vapour resistance, ZP, of an insulation system with n different layers is given by:njjjjDDZ11P2ln(9)which gives,110Pln21jjnjjDDZ (10)wherejj0j = 1 to n defines the layers from the cold pipe outwards.Equation (10) can also be used for a homogeneous insulation material with water vapourresistance highly dependent on temperature.NOTE
See Example A.2.If the outer layer, n, is a vapour retarder jacket, foil or skin, with negligible thickness, but withlarge water vapour diffusion-equivalent air layer thickness sdf, the water vapour resistance ofthe retarder will be:nnnDssDZdf0df02 211(11)The water vapour resistance of the whole system is then:njjnjjDsDDZdf1110P2ln21(12)SIST EN 14114:2002
EN 14114:2002 (E)9The total water uptake over a period t is then given by Equation (8).4.4 Systems with capacity for dryingFor cold pipe systems with drying-out capacities the total water uptake G’ in the system isgiven by:tggGtd0e(13)where ge is the drying capacity per linear metre of pipe, in kg/(ms).For insulation systems, where the drying capacity is obtained by uti
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