ASTM E241-00
(Guide)Standard Guide for Limiting Water-Induced Damage to Buildings
Standard Guide for Limiting Water-Induced Damage to Buildings
SCOPE
1.1 This guide concerns building design, construction, commissioning, operation and maintenance.
This guide addresses the need for systematic evaluation of factors that can result in moisture-induced damage to a building or its components. Although of great potential importance, serviceability issues which are often, but not necessarily, related to physical damage of the building or its components (for example indoor air quality of electrical safety) are not directly addressed in this guide.
1.3 The emphasis of this guide is on low-rise buildings. Portions of this guide, in particular sections 5, 6, and 7, may also be applicable to high-rise buildings.
1.4 This standard is not intended for direct use in codes and specifications. It does not attempt to prescribe acceptable limits of damage. Buildings intended for different uses may have different service life expectancies, and expected service lives of different components within a given building often differ. Furthermore, some building owners may be satisfied with substantially shorter service life expectancies of building components or of the entire building than other building owners. Lastly, the level of damage that renders a component unservicable may vary with the type of component, the degree to which failure of the component is critical (for example whether failure constitutes a life-safety hazard), and the judgement (i.e. tolerance for damage) of the building owner. For the reasons stated in this paragraph, prescribing limits of damage would require listing many pages of exceptions and qualifiers and is beyond the scope of this standard.
1.5 This standard does not purport to address the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E 241 – 00 An American National Standard
Standard Guide for
Limiting Water-Induced Damage to Buildings
This standard is issued under the fixed designation E 241; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope C 717 Standard Definitions of Terms Relating to Building
Seals and Sealants
1.1 This guide concerns building design, construction, com-
C 755 Practice for Selection of Vapor Retarders for Thermal
missioning, operation and maintenance.
Insulation
1.2 This guide addresses the need for systematic evaluation
C 1193 Standard Guide for Use of Joint Sealants
of factors that can result in moisture-induced damage to a
D 1079 Standard Definitions of Terms Relating to Roofing,
building or its components. Although of great potential impor-
Waterproofing, and Bituminous Materials
tance, serviceability issues which are often, but not necessarily,
E 331 Test Method for Water Penetration of Exterior Win-
related to physical damage of the building or its components
dows, Curtain Walls and Doors by Uniform Static Air
(for example indoor air quality or electrical safety) are not
Pressure Difference
directly addressed in this guide.
E 547 Test Method Water Penetration of Exterior Windows,
1.3 The emphasis of this guide is on low-rise buildings.
Curtain Walls, and Doors by Cyclic Static Air Pressure
Portions of this guide, in particular sections 5, 6, and 7, may
Differential
also be applicable to high-rise buildings.
E 631 Terminology of Building Constructions
1.4 This standard is not intended for direct use in codes and
E 632 Practice for Developing Accelerated Tests to Aid
specifications. It does not attempt to prescribe acceptable limits
Prediction of the Service Life of Building Components and
of damage. Buildings intended for different uses may have
Materials
different service life expectancies, and expected service lives
E 1105 Test Method for Field Determination of Water
of different components within a given building often differ.
Penetration of Installed Exterior Windows, Curtain Walls,
Furthermore, some building owners may be satisfied with
and Doors by Uniform or Cyclic Static Air Pressure
substantially shorter service life expectancies of building
Difference
components or of the entire building than other building
E 1643 Practice for Installation of Water Vapor Retarders
owners. Lastly, the level of damage that renders a component
Used in Contact with Earth or Granular Fills and Concrete
unserviceable may vary with the type of component, the degree
Slabs
to which failure of the component is critical (for example
E 1677 Standard Specification for an Air Retarder Material
whether failure constitutes a life-safety hazard), and the judge-
or System for Low-Rise Framed Building Walls
ment (i.e. tolerance for damage) of the building owner. For the
E 1745 Specification for Water Vapor Retarders Used in
reasons stated in this paragraph, prescribing limits of damage
Contact with Soil or Granular Fill Under Concrete Slabs
would require listing many pages of exceptions and qualifiers
2.2 Other Documents:
and is beyond the scope of this standard.
ASHRAE Handbook of Fundamentals (1997) Chapter 22:
1.5 This standard does not purport to address the safety
Thermal and moisture control in insulated assemblies -
problems associated with its use. It is the responsibility of the
fundamentals. Amer. Soc. of Heating Refrigerating, and
user of this standard to establish appropriate safety and health
Air Conditioning Engineers, Atlanta, GA.
practices and determine the applicability of regulatory limita-
ASHRAE Standard 55, Thermal Environmental Conditions
tions prior to use.
for Human Occupancy
2. Referenced Documents
ASHRAE Standard 62, Ventilation for Acceptable Indoor
Air Quality
2.1 ASTM Standards:
ASHRAE Technical Data Bulletin Vol. 10 Number 3. Rec-
C 168 Terminology Relating to Thermal Insulating Materi-
ommended Practices for Controlling Moisture in Crawl
als
Spaces, Amer. Soc. of Heating Refrigerating and Air
Conditioning Engineers, Atlanta, GA., 1994.
This guide is under the jurisdiction of ASTM Committee E06 on Building
Bateman, R. Nail-On Windows: Installation & Flashing
Constructions and is the direct responsibility of Subcommittee E06.41 on Air
Leakage and Ventilation.
Current edition approved June 10, 2000. Published August 2000. Originally
published as E 241–64T. Last previous edition E 241–90. Annual Book of ASTM Standards, Vol 04.11.
2 4
Annual Book of ASTM Standards, Vol 04.06. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 241
Procedures for Windows & Sliding Glass Doors. DTA, 3.3.1 ventilation, n—the intentional introduction of air from
Inc., Mill Valley, CA. 1995. the outside of a building.
Connolly, J. “Humidity and Building Materials” in Proceed-
3.3.2 infiltration, n—the uncontrolled flow of outdoor air
ings: Bugs, Mold & Rot II (W. Rose and A. TenWolde,
into a building through cracks and other unintentional openings
eds). National Institute of Building Sciences, Washington
and through the normal use of exterior doors for entrance and
DC. 1993.
egress.
Lstiburek, J. and J. Carmody. “Moisture Control Handbook:
3.3.3 exfiltration, n—the uncontrolled flow of indoor air out
New, Low-rise, Residential Construction”, prepared for
of a building through cracks and other unintentional openings
U. S. Dept. of Energy. 1991.
and through the normal use of exterior doors for entrance and
Trechsel, H. (ed.) “Moisture Control in Buildings” Ameri-
egress.
can Society for Testing and Materials, ASTM MNL 18,
3.4 Definitions of Terms Specific to This Standard:
West Conshohocken, PA, 1994.
3.4.1 air leakage, n—infiltration or exfiltration, in other
Timusk, J., Seskus, A., and K. Linger. 1992. A systems
words uncontrolled air flow into or out of a building through
approach to extend the limit of envelope performance. In
cracks and other unintentional openings and through normal
Proceedings: Thermal Performance of the Exterior Enve-
use of exterior doors for entrance and egress.
lopes of Buildings V. Amer. Soc. of Heating, Refrigerat-
3.4.2 building component, n—an inclusive term to collec-
ing, and Air-Conditioning Engineers (ASHRAE), Atlanta,
tively refer to building materials, products, or assemblies.
GA.
3.4.3 capillary break, n—a term applied to a material, most
3. Terminology commonly a synthetic membrane material, used to limit liquid
water transfer by diffusion or capillary suction from wet
3.1 Standard Definitions—Refer to Terminologies C 168,
ground or from a wet or damp building component to another
C 717, D 1079, and E 631 for definitions of general terms.
building component that can absorb liquid water.
Three definitions from C 168 are reiterated (verbatim) in
3.4.3.1 Discussion—Capillary breaks may also be com-
3.1.1-3.1.3.
posed of corrosion-resistant sheet metal, asphalt impregnated
3.1.1 vapor retarder (barrier), n—a material or system that
and coated felt, or where lesser degrees of resistance to
adequately impedes the transmission of water vapor under
capillary transfer are required, asphalt-impregnated felt.
specified conditions.
3.4.4 critical moisture content, n—a moisture condition
3.1.1.1 Discussion—For low-rise residential construction,
parameter. This parameter is expressed as a moisture content
materials or components with a water vapor permeance not
level above which immediate or virtually immediate damage
exceeding one perm are generally considered vapor retarders
will occur to a building component at a given temperature,
(see Practice C 755).
such that the level of damage is deemed unacceptable.
3.1.2 water vapor permeance, n—the time rate of water
3.4.5 critical cumulative exposure time, n—a moisture con-
vapor transmission through unit area of fiat material or
dition parameter, this parameter is expressed as a time sum
construction induced by unit vapor pressure difference between
when moisture conditions are above a level that results in
two specific surfaces, under specified temperature and humid-
cumulative damage to a building component, such that the
ity conditions.
level of cumulative damage is deemed unacceptable.
3.1.2.1 Discussion—Permeance is a performance evaluation
and not a property of a material. 3.4.5.1 Discussion—cumulative damage to a component
3.1.3 water vapor permeability, n—the time rate of water may occur over a range of moisture and temperature combi-
nations, and damage is frequently more rapid at some combi-
vapor transmission through unit area of flat material of unit
thickness induced by unit vapor pressure difference between nations than at others. The differing rate of damage accumu-
two specific surfaces, under specified temperature and humid- lation at different sets of conditions is accounted for with
ity conditions. intensity factors, which are discussed in Chapter 26 of ASTM
3.1.3.1 Discussion—Permeability is a property of a mate- MNL 18.
rial. Permeability is the arithmetic product of permeance and
3.4.6 durability, n—in constructions, the capacity of a
thickness.
building component or a construction to remain serviceable as
3.2 Other definitions found in ASTM Standards: intended with usual and customary operation and maintenance
3.2.1 air retarder, n—a material or system in building
during the designed service-life under anticipated internal and
construction that is designed and installed to reduce air leakage external environments.
either into or through an opaque wall or across a ceiling.
3.4.7 flashing, n—a term applied to elements, most com-
monly fabricated of sheet metal, but which may also be
NOTE 1—Source of this definition is ASTM D 1677.
fabricated of synthetic materials, used at interruptions and
3.2.2 opaque wall, n—exposed areas of a wall that enclose
terminations of water shedding systems of roofs and walls, and
conditioned space, except openings for windows, doors and
intended to prevent intrusion of liquid water at these points.
building service systems.
3.4.8 limit, v—to keep the value or level of some parameter,
NOTE 2—Source of this definition is ASTM D 1677.
which is recognized as being problematic or potentially prob-
3.3 Consensus Definitions from Other Sources: The follow- lematic, below a value or level which is deemed to be
objectionable.
ing definitions are taken verbatim from the ASHRAE Hand-
book of Fundamentals (1997). 3.4.9 limit state, n—a value which expresses a moisture
E 241
condition parameter, generally a critical moisture content or a amples of constructions or circumstances to avoid. The ex-
critical cumulative exposure time, that is deemed to be at the amples listed are not all-inclusive. Lastly, field check lists are
border of what is acceptable, and beyond which an unaccept- given. The checklists are not intended for use as is, but as
able level of damage to a building component may be guides for development of checklists which may vary with
expected. specific building designs and climates.
3.4.10 perm, n—the time rate of water vapor migration by
5. Moisture Sources and Migration
diffusion through a material or component equal to 1 grain per
5.1 Moisture sources for buildings can be broadly classified
hour, square foot, inch of mercury vapor pressure difference. In
as follows: (1) surface runoff of precipitation from land areas,
SI units, one perm is 57.2 ng/(Pabsbm ).
(2) ground water or wet soil, (3) precipitation or irrigation
3.4.11 serviceability, n—in a construction, the capacity of a
water that falls on the building, (4) indoor humidity, (5)
building component or a construction to perform the func-
outdoor humidity, (6) moisture from use of wet building
tion(s) for which it was designed and constructed.
materials or construction under wet conditions and (7) errors,
3.4.12 water or moisture, n—water as liquid, vapor, or solid
accidents and maintenance problems associated with indoor
(ice, frost, or snow) in any combination or in transition.
plumbing. At a given instant of time the categories are distinct
4. Significance and Use
from each other. Water can change phase and can be trans-
4.1 Moisture degradation is frequently a significant factor ported over space by various mechanisms. Water may therefore
that either limits the useful life of a building or necessitates be expected to move between categories over time, blurring the
costly repairs. Examples of moisture degradation include: 1) distinctions between categories. Chapter 8 of ASTM MNL 18
decay of wood-based materials, 2) spalling of masonry caused provides quantitative estimates of potential moisture load from
by freeze-thaw cycles, 3) damage to gypsum plasters by various sources.
dissolution, 4) corrosion of metals, 5) damage due to expansion 5.1.1 High indoor humidity during winter is often a major
of materials or components (by swelling due to moisture cause of moisture problems in cold or temperate climates.
pickup, or by expansion due to corrosion, hydration, or delayed Moisture-induced damage may be expected unless the building
ettringite formation), 6) spalling and degradation caused by salt is designed to tolerate the levels of indoor humidity that occur
migration, 7) failure of finishes and 8) creep deformation and in use. Conversely, moisture induced damage may be expected
reduction in strength or stiffness. unless indoor humidity is kept within limits that the building
4.1.1 Moisture accumulation within construction compo- will tolerate. Buildings should be designed and built so as to
nents or constructions may adversely affect serviceability of a tolerate indoor humidity levels commensurate with their in-
building, without necessarily causing immediate and serious tended use. For some buildings, (for example: those intended
degradation of the construction components. Examples of such for habitation by persons with certain medical conditions or
serviceability issues are: 1) indoor air quality, 2) electrical those housing swimming pools or textile production equip-
safety, 3) degradation of thermal performance of insulations ment), the levels of indoor humidity which the building should
and 4) decline in physical appearance. Mold or mildew growth be expected to tolerate are moderately high, even if the
can influence indoor air quality and physical appearance. With building is located in a cold climate. Conversely however, most
some components, in particular interior surface finishes, mold buildings are not designed nor built to tolerate high
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