ASTM E3054/E3054M-23

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Designation: E3054/E3054M − 16 E3054/E3054M − 23
Standard Guide for
Characterization and Use of Hygrothermal Models for
Moisture Control Design in Building Envelopes
This standard is issued under the fixed designation E3054/E3054M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This guide offers guidance for the characterization and use of hygrothermal models for moisture control design of building
envelopes. In this context, “hygrothermal models” refers to the application of a mathematical model to the solution of a specific
heat and moisture flow performance issue or problem. Hygrothermal models are used to predict and evaluate design considerations
for the short-term and long-term thermal and moisture performance of building envelopes.
1.2 Each hygrothermal model has specific capabilities and limitations. Determining the most appropriate hygrothermal model for
a particular application requires a thorough analysis of the problem at hand, understanding the required transport processes
involved, and available resources to conduct the analysis. Users of this guide can describe the functionality of the hygrothermal
model used in an analysis in a consistent manner.
1.3 This guide applies to hygrothermal models that range from complex research tools to simple design tools. This guide provides
a protocol for matching the analysis needs and the capabilities of candidate models.
1.4 This guide applies to the use of models that include all or part of the following thermal and moisture storage and transport
phenomena: (1) heat storage of dry and wet building materials, (2) heat transport by moisture-dependantmoisture-dependent
thermal conduction, (3) phase change phenomena (for example, evaporation and condensation), (4) heat transport by air
convection, (5) moisture retention by vapor adsorption and capillary forces, (6) moisture transport by vapor diffusion (molecular
and effusion), (7) moisture transport by liquid transport (surface diffusion and capillary flow), and (8) moisture (vapor) transport
by air convection.
1.5 This guide does not apply to cases requiring analysis of the following: (1) convection that occurs in a three-dimensional
manner or through holes and cracks; (2) hydraulic, osmotic, or electrophoretic forces; (3) salt or other solute transport; or (4)
material properties that change with age.
1.6 This guide intends to provide guidance regarding the reliability of input and how the corresponding results can be affected as
well as a format for determining such information.
1.7 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in
each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, and values from the two systems shall not be combined.
This guide is under the jurisdiction of ASTM Committee E06 on Performance of Buildings and is the direct responsibility of Subcommittee E06.41 on Air Leakage and
Ventilation Performance.
Current edition approved March 15, 2016Jan. 1, 2023. Published May 2016January 2023. Originally approved in 2016. Last previous edition approved in 2016 as
E3054/E3054M–16. DOI: 10.1520/E3054_E3054M-16.10.1520/E3054_E3054M-23.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E3054/E3054M − 23
1.8 This guide offers an organized characterization of hygrothermal models and does not recommend a specific course of action.
This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all
aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the
standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied
without consideration of a project’s many unique aspects. The word “Standard” in the title of this document means only that the
document has been approved through the ASTM International consensus process.
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.10 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C168 Terminology Relating to Thermal Insulation
E283E283/E283M Test Method for Determining Rate of Air Leakage Through Exterior Windows, Skylights, Curtain Walls, and
Doors Under Specified Pressure Differences Across the Specimen
E331 Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform Static Air
Pressure Difference
E631 Terminology of Building Constructions
E2273 Test Method for Determining the Drainage Efficiency of Exterior Insulation and Finish Systems (EIFS) Clad Wall
Assemblies
E2357 Test Method for Determining Air Leakage Rate of Air Barrier Assemblies
2.2 Other Standards:
ANSI/ASHRAE 160-2009 Criteria for Moisture-Control Design Analysis in Buildings
DIN EN 15026 Hygrothermal performance of building components and building elements - Assessment of moisture transfer by
numerical simulation
WTA Guideline 6-2-01 Simulation of Heat and Moisture Transfer
3. Terminology
3.1 Definitions: For definitions of terms used in this guide, see Terminologies C168 and E631.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 air-leakage rate, n—volume of air movement per unit time across the building envelope.
3.2.1.1 Discussion—
this movement includes flow through joints, cracks, and porous surfaces, or a combination thereof. The driving force for such an
air leakage in service can be mechanical pressurization and depressurization, natural wind pressures, or air temperature differentials
between the building interior and the outdoors, or a combination thereof.
3.2.2 analytical model, n—model that uses closed form closed-form solutions to the governing equations applicable to
hygrothermal flow and transport processes.
3.2.3 building envelope, n—boundary or barrier separating the interior volume of a building from the outside environment or
different interior environment.
3.2.3.1 Discussion—
For the purpose of this guide, the interior volume is the deliberately conditioned space within a building, generally not including
attics, basements, and attached structures, for example, garages, unless such spaces are connected to the heating and air
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
Available from American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. (ASHRAE), 1791 Tullie Circle, NE, Atlanta, GA 30329,
http://www.ashrae.org.
Available from Deutsches Institut für Normung e.V.(DIN), e.V. (DIN), Am DIN-Platz, Burggrafenstrasse 6, 10787 Berlin, Germany, http://www.din.de.
Available from WTA-Publications, Ingolstädter StraßeWissenschaftlich-Technische Arbeitsgemeinschaft für Bauwerkserhaltung und Denkmalpflege (WTA) e.V.,
Ingolstädter Str. 102, D-85276 Pfaffenhofen, Germany, http://www.wta-international.org/?L=2.http://www.wta-international.org.
E3054/E3054M − 23
conditioning system, such as a crawl space plenum. The outside environment may be weather conditions or any other known
conditions that the exterior of the building envelope is exposed to. An interior partition that separates two dissimilar environments
such as a cold storage facility adjacent to an occupied office can be treated as a building envelope element for the modeling
purposes.
3.2.4 building envelope model, n—portion of the building envelope, such as a wall, roof, floor, window, or door, or a combination
thereof. The building envelope model comprises all of the components and materials as they are configured within the
buidlingbuilding envelope assembly (for example, the wall or roof assembly) at a given location.
3.2.5 computer code (computer program), n—assembly of numerical techniques, bookkeeping, and control language that
represents the model from acceptance of input data and instructions to delivery of output.
3.2.6 conceptual model, n—interpretation or working description of the characteristics and dynamics of the physical system.
3.2.7 finite difference model, n—type of approximate, numerical model that uses a discretization technique to linearize the
governing partial differential equations (PDE) consisting of replacing the continuous domain of interest by a finite array of spaced
mesh or grid points (that is, nodes) spaced along the coordinate direction(s) of the one-, two-, or three-dimensional geometric
coordinate system. The grid points define a set of control volumes representing volume-averaged subdomain properties. The
derivatives of the PDE for each of these points are approximated using finite differences. The resulting set of linear or nonlinear
algebraic equations are solved using direct or iterative matrix-solving techniques.
3.2.8 finite element model, n—type of approximate, numerical model that uses a discrete technique for solving the governing PDE
wherein the domain of interest is represented by a finite number of mesh or grid points (that is, nodes), information between these
points is obtained by interpolation using piecewise continuous polynomials, and the resulting set of linear or nonlinear algebraic
equations is solved using direct or iterative matrix-solving techniques.
3.2.9 functionality, n—of a hygrothermal model, the set of functions and features the model offers the user in terms of building
envelope framework geometry, simulated processes, initial and boundary conditions, and analytical and operational capabilities.
3.2.10 hygrothermal model, n—a mathematical model that includes various thermal and moisture transport mechanisms with
boundary system performance under applied conditions to represent a building envelope system or subsystem.
3.2.10.1 Discussion—
May be either steady-state or transient approach and may be based on equations derived from basic principles of physics,
established engineering functional relationships, statistical interpretations of empirical data, or a combination of all of these
approaches.
3.2.11 hygrothermal model code, n—computer code used in hygrothermal modeling to represent a non-unique, simplified
mathematical description of the physical framework, geometry, active processes, and initial and boundary conditions present in a
building system.
3.2.12 model selection, n—process of choosing the appropriate computer model as an analysis tool capable of simulating those
characteristics of the physical system required to fulfill the project’s objective(s).
3.2.13 Moisture Reference Year, MRY—a year of hourly weather data that have been selected for use in hygrothermal analysis.
3.2.14 numerical model, n—model that uses numerical methods to solve the governing equations of the applicable problem.
3.2.15 water penetration, n—a process in which water gains access into a material or system by passing through the surface
exposed to the water.
3.2.15.1 Discussion—
For products with non-planar glazing surfaces (domes, vaults, pyramids, and so forth), the plane defining water penetration is the
plane defined by the innermost edges of the unit frame.
3.3 Symbols:
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2 2
q = mass flux rate of vapor flow (kg/m ·s [lb/ft s])
v
3 3
X = vapor concentration (kg/m [lb/ft ])
δ = water vapor permeability (kg/Pa·m·s [Perm-in])
p
h = specific latent heat of evaporation or condensation (J/kg [Btu/lb])
e
h = specific latent heat of fusion (freezing or melting) (J/kg [Btu/lb])
f
2 2
g = air mass flux (kg/m s [lb/ft s])
air
3 3
I = moisture content changing phase from ice to liquid (kg/m s [lb/ft s])
il
λ = thermal conductivity (W/mK [Btu/h·ft·°F])
m = mass of dry material (kg [lb])
dry
m = mass of wet material (kg [lb])
wet
P = air pressure (Pa [psi])
air
P = exterior air pressure (Pa [psi])
e
P = interior pressure (Pa [psi])
i
3 3
ρ = density of water (kg/m [lb/ft ])
w
3 3
ρ = dry density of material (kg/m [lb/ft ])
s
3 3
ρ = dry density of material (kg/m [lb/ft ])
air
c = specific heat capacity of liquid water (J/kgK
w
[Btu ⁄lb°F])
c = specific heat capacity of dry material (J/kgK
s
[Btu ⁄lb°F])
c = specific heat capacity of dry air (J/kgK [Btu/lb°F])
a
η = dynamic viscosity (s·Pa [lb·s/ft ])
2 2
k = air permeability (m [ft ])
a
T = temperature (K [°F])
ϕ = relative humidity (-)
2 2
q = liquid transport flow (kg/m s [lb/ft s])
l
u = moisture content (kg/kg [lb/lb])
t = time (s) (s)
t = time (s)
x = x–coordinate
D = liquid conduction coefficient (kg/ms [lb/ft•s])
ϕ
4. Significance and Use
4.1 This guide is intended to provide the framework for characterizing the functions of the hygrothermal model and the level of
sophistication used as inputs for each analysis. Hygrothermal modeling has become an important practice in support of the
decision-making design processes involved in moisture management of building envelope systems. Increasingly, hygrothermal
models are an integral part of building envelope performance assessment, retrofit, and restoration studies and provide insight in
the screening of alternative design approaches affecting water management of the envelope system. Hygrothermal models are used
in decision making during the design process of building envelope systems. They may also be used to assess performance of the
envelopes of existing buildings, or to predict envelope performance in buildings undergoing retrofit, change in use, restoration or
flood remediation. It is, therefore, important to have a methodology to document the model used in a hygrothermal investigation.
This documentation provides needed characterization of the hygrothermal model to assess its credibility and suitability. This
becomes even more important because of the increasing complexity of the building envelope systems for which new hygrothermal
models are being developed. There are many different hygrothermal models available, each with specific capabilities, operational
characteristics, and limitations. If modeling is considered for a project, it is important to determine if a hygrothermal model is
appropriate for that project, or if a model exists that can perform the simulations required in the project.
4.2 Quality assurance in a hygrothermal analysis using modeling is achieved by using the most appropriate model with all
important transport mechanisms, initial conditions, and boundary conditions. A well-executed quality assurance program in
hygrothermal modeling requires systematic and complete documentation of the model and the inputs followed by consistent
reporting of the results. This guide sets forth a format for reporting hygrothermal modeling results.
5. Hygrothermal Model Analysis Inputs
5.1 There are many hygrothermal models available to simulate, describe, or analyze different building envelope systems and the
moisture migration characteristics that affect their performance. Therefore, it is important to understand the performance
characteristics for which the model is intended to represent and recognize the evaluation of the model is only relevant for the
performance characteristics it addresses. If the appropriate analytical and input techniques are applied to the model, then the results
obtained should provide a valid solution to address the system deficiencies. Fig. 1 displays the various inputs and outputs needed
E3054/E3054M − 23
FIG. 1 Input and Output Chart for Hygrothermal Simulations
for hygrothermal simulations. The effectiveness of the results is largely a function of the degree to which the model represents the
system studied. Additionally, the inputs (climate data, orientation inclination, and material characteristics) are not addressed. Their
influence on the calculation results are,is, however, very important (often more important than the capability of the hygrothermal
model). This standardguide is complimentarycomplementary to the ASHRAE 160 Standard, DIN EN 15026, and WTA Guideline
6-2-01 that describes the design criteria for use in hygrothermal models.
5.2 A descriptive approach that can be used to classify hygrothermal models is discussed in the following. Fig. 2 describes
graphically the descriptive approach proposed in this standard. Additional information related to the classification details are found
6 7 8
in Karagiozis, Trechsel (Chapter 1), and Kuenzel.
5.2.1 Nature of Equations (D, S)—Decision-making problems can be classified into two ca
...