ASTM D7338-10
(Guide)Standard Guide for Assessment Of Fungal Growth in Buildings
Standard Guide for Assessment Of Fungal Growth in Buildings
SIGNIFICANCE AND USE
This guide presents options for a systematic assessment of fungal growth in buildings.
This guide allows for site-specific flexibility and professional judgment in the choice of assessment procedures. It may not be necessary to perform in its entirety the basic assessment presented below to resolve a particular problem, for example, where fungal growth is localized and the source and extent of moisture is readily observable.
Conversely, no matter how comprehensive the survey, all fungal growth may not be identified or located in a fungal assessment.
Material removal or destructive investigation may be needed to access suspect surfaces.
Using the procedures described in this guide, the investigator may have obtained the data necessary to suggest specific recommendations, for example, how to remediate the observed fungal growth, or how to prevent further fungal growth, but those recommendations are beyond the scope of this guide.
Precautions may be needed to protect the assessor and building occupants where access may disturb fungal growth.
It is the user’s responsibility to protect information that may be considered confidential, or private, or both, in accordance with project contract, corporate protocol, or local, state, and federal regulations, or a combination thereof.
It may be necessary to enlist other disciplines or trade expertise to assist in some steps of the assessment, but recommendations of when to enlist and whom to enlist are beyond the scope of this guide.
SCOPE
1.1 This guide provides a compendium of information and a menu of options for assessment of fungal growth in buildings, but does not recommend a specific course of action. Due to the wide variety of fungal problems affecting buildings and their occupants, and the wide variety of buildings, it is not possible to describe a set of uniform steps that will always be performed during an assessment (that is, a standard practice); therefore the user of this guide must decide which steps are appropriate for a given situation or building.
1.2 This guide is specific to fungal growth, which is only one potential problem in a building environment. It may be part of, but is not intended to take the place of, a comprehensive indoor air quality investigation.
1.3 This guide describes minimum steps and procedures for collecting background information on a building in question, procedures for evaluating the potential for moisture infiltration or collection, procedures for inspection for suspect fungal growth, and procedures beyond the scope of a basic survey that may be useful for specific problems.
1.4 Assessments for fungal growth may be useful wherever fungal growth is suspected, excess moisture has been present or when there are concerns regarding potential fungal growth.
1.5 Periodic fungal assessment in buildings may be a component of preventative maintenance programs.
1.6 This guide is applicable to buildings including residential (for example, single or multi-family), institutional (for example, schools, hospitals), government, public assembly, commercial (for example, office, retail), and industrial facilities.
1.7 Recommendations for developing a sampling strategy or methods for the collection and analysis of fungal samples are beyond the scope of this guide. For recommendations for developing a sampling strategy, see Ref (27) , Chapter 10.
1.8 Recommendations for remediation of fungal growth are beyond the scope of this guide.
1.9 This guide is not intended to supersede any government regulations governing the assessment of fungal growth in buildings.
1.10 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D7338 − 10
StandardGuide for
Assessment Of Fungal Growth in Buildings
This standard is issued under the fixed designation D7338; 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 1.8 Recommendations for remediation of fungal growth are
beyond the scope of this guide.
1.1 This guide provides a compendium of information and a
menu of options for assessment of fungal growth in buildings, 1.9 This guide is not intended to supersede any government
but does not recommend a specific course of action. Due to the regulations governing the assessment of fungal growth in
wide variety of fungal problems affecting buildings and their buildings.
occupants, and the wide variety of buildings, it is not possible
1.10 This standard does not purport to address all of the
todescribeasetofuniformstepsthatwillalwaysbeperformed
safety concerns, if any, associated with its use. It is the
duringanassessment(thatis,astandardpractice);thereforethe
responsibility of the user of this standard to establish appro-
user of this guide must decide which steps are appropriate for
priate safety and health practices and determine the applica-
a given situation or building.
bility of regulatory limitations prior to use.
1.2 This guide is specific to fungal growth, which is only
2. Referenced Documents
onepotentialprobleminabuildingenvironment.Itmaybepart
of, but is not intended to take the place of, a comprehensive
2.1 ASTM Standards:
indoor air quality investigation.
C755 Practice for Selection of Water Vapor Retarders for
Thermal Insulation
1.3 This guide describes minimum steps and procedures for
C1699 Test Method for Moisture Retention Curves of Po-
collecting background information on a building in question,
rous Building Materials Using Pressure Plates
procedures for evaluating the potential for moisture infiltration
D653 Terminology Relating to Soil, Rock, and Contained
or collection, procedures for inspection for suspect fungal
Fluids
growth,andproceduresbeyondthescopeofabasicsurveythat
D4442 Test Methods for Direct Moisture Content Measure-
may be useful for specific problems.
ment of Wood and Wood-Base Materials
1.4 Assessments for fungal growth may be useful wherever
E331 Test Method for Water Penetration of Exterior
fungal growth is suspected, excess moisture has been present
Windows, Skylights, Doors, and Curtain Walls by Uni-
or when there are concerns regarding potential fungal growth.
form Static Air Pressure Difference
1.5 Periodic fungal assessment in buildings may be a
E547 Test Method for Water Penetration of Exterior
component of preventative maintenance programs.
Windows, Skylights, Doors, and Curtain Walls by Cyclic
Static Air Pressure Difference
1.6 This guide is applicable to buildings including residen-
E631 Terminology of Building Constructions
tial (for example, single or multi-family), institutional (for
E1105 Test Method for Field Determination of Water Pen-
example, schools, hospitals), government, public assembly,
etration of Installed Exterior Windows, Skylights, Doors,
commercial (for example, office, retail), and industrial facili-
and Curtain Walls, by Uniform or Cyclic Static Air
ties.
Pressure Difference
1.7 Recommendationsfordevelopingasamplingstrategyor
E1186 Practices for Air Leakage Site Detection in Building
methods for the collection and analysis of fungal samples are
Envelopes and Air Barrier Systems
beyond the scope of this guide. For recommendations for
E1356 Test Method for Assignment of the Glass Transition
developing a sampling strategy, see Ref (27) , Chapter 10.
Temperatures by Differential Scanning Calorimetry
E2128 Guide for Evaluating Water Leakage of Building
Walls
This guide is under the jurisdiction of ASTM Committee D22 on Air Quality
and is the direct responsibility of Subcommittee D22.08 on Sampling and Analysis
of Mold.
Current edition approved Dec. 1, 2010. Published January 2011. DOI:10.1520/ For referenced ASTM standards, visit the ASTM website, www.astm.org, or
D7338-10. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
The boldface numbers in parentheses refer to a list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7338 − 10
E2270 Practice for Periodic Inspection of Building Facades 3.2.6 hypha, n—(pl. hyphae) tubular filament of fungal
for Unsafe Conditions cells; the basic vegetative structure of the body of fungi
(excluding yeasts).
2.2 Non-ASTM Standards:
ANSI/GEI Standard MMS1001 Mold and Moisture Man- 3.2.7 fungal growth, n—vegetative portion of a fungus.
agement Standard for New Construction
3.2.8 infrared thermography, n—thermal imaging, also
called thermography, is the production of non-contact infrared,
3. Terminology
or “heat” pictures from which temperature measurements can
3.1 Definitions: be made.
3.1.1 building envelope, n—the outer elements of a
3.2.9 remediation, n—to correct a problem. Related to
building, both above and below ground, which divide the
fungal contamination, remediation includes correcting the
external from the internal environments. Commonly included
water and moisture problems and the cleaning, removal, and/or
are exterior walls, windows, doors, roofs and subfloors. E631
replacement of mold-damaged or -contaminated materials.
3.1.2 bulk sample, n—piece or quantity of bulk material that
3.2.10 thermal bridging, n—a phenomenon that occurs
has been selected by some sampling process. D653
when heat is transferred at a substantially higher rate through
3.1.3 capillary action, n—(or capillary migration), of water, a component, or assembly of components in a building
movement of water induced by the force of molecular attrac-
envelope, than through the surrounding envelope area.
tion (surface tension) between the water and the material it
contacts. E631
4. Summary of Guide
3.1.4 condensation, n—the process of converting a material
4.1 This guide presents a framework for locating and
in the gaseous phase to a liquid by decreasing temperature or
evaluating suspect fungal growth in buildings. Topics include
by increasing pressure, or both. E1356
background information, a basic assessment strategy and
additional or advanced procedures.
3.1.5 exposure, n—contact with a chemical, biological,
physical, or other agent over a specified time period. E1356
4.2 Components of a basic assessment strategy may include
3.1.6 moisture content, n—mass of water retained in the (1) defining a scope of work, (2) collecting background
specimen divided by the dry mass of the specimen. C1699 information on the building and building systems, (3) formu-
lation of a hypothesis or hypotheses, (4) an on-site survey for
3.1.7 soot,n—agglomerationsofparticlesofcarbonimpreg-
fungi, moisture dynamics, and heating. ventilating and air
nated with tar, formed in the incomplete combustion of
conditioning (HVAC) operation, and (5) documentation and
carbonaceous material. E1356
reporting. Every component of the basic assessment shown
3.1.8 vapor retarder, n—a material or system that ad-
below may be considered optional, since even some of the
equately impedes the transmission of water vapor under
most basic steps may not be needed for certain well-defined
specified conditions. E631
situations.
3.2 Definitions of Terms Specific to This Standard:
4.3 When the information from the basic assessment is
3.2.1 boroscope, n—device for internal inspection of diffi-
insufficient to support decision-making, additional procedures
cult access locations such as wall cavities. Its long narrow tube
for a follow-up study may include: (1) characterizing site
contains a telescope system with a number of relay lenses.
moisture in greater detail to assist in locating suspect fungal
Light is provided via the optical path or fiber bundles.
growth and controlling excess moisture; (2) accessing surfaces
3.2.2 effloresce, v—process by which water leaches soluble likely to harbor hidden fungal growth; and/or (3) sampling if
salts out of concrete or mortar for surface deposit. Also
necessary to test a specific hypothesis.
efflorescence, n, the name for these deposits.
5. Significance and Use
3.2.3 enzyme activity, n—measure of the quantity of active
enzyme present. Enzyme activity is essential to metabolism.
5.1 This guide presents options for a systematic assessment
Specifically, beta-N-acetylhexosaminidase (NAHA) is an en-
of fungal growth in buildings.
zyme present in all filamentous fungi, the measurement of
5.2 This guide allows for site-specific flexibility and profes-
whichhasbeenshowntobedirectlyproportionaltotheamount
sional judgment in the choice of assessment procedures. It may
of fungal biomass (see (18, 28).
not be necessary to perform in its entirety the basic assessment
3.2.4 fungus, n—(pl. fungi) a kingdom of organisms includ-
presented below to resolve a particular problem, for example,
ing molds, mildews, mushrooms, yeasts and many parasites.
where fungal growth is localized and the source and extent of
These are important decomposers in ecosystems. Fungi are
moisture is readily observable.
typically multi-cellular fungi with filamentous vegetative hy-
5.3 Conversely, no matter how comprehensive the survey,
phae.
all fungal growth may not be identified or located in a fungal
3.2.5 fungal spore, n—general term for a reproductive
assessment.
structure in fungi. The spore is the structure that may be used
for dissemination and reproduction, and may be resistant to 5.4 Material removal or destructive investigation may be
adverse environmental conditions. needed to access suspect surfaces.
D7338 − 10
5.5 Using the procedures described in this guide, the inves- 6.2.2.1 substrate porosity (for example, materials such as
tigator may have obtained the data necessary to suggest carpet tack strip and conventional drywall are highly
specific recommendations, for example, how to remediate the susceptible),
observed fungal growth, or how to prevent further fungal 6.2.2.2 moisture resistance (for example, some drywall,
growth, but those recommendations are beyond the scope of
gypsum plaster and sheathing products are modified to resist
this guide. moisture or to limit water storage and/or are treated with an
anti-microbial agent),
5.6 Precautions may be needed to protect the assessor and
6.2.2.3 moisture duration (for example, leaks which are
building occupants where access may disturb fungal growth.
single events or intermittent may dry before fungal growth is
5.7 It is the user’s responsibility to protect information that
initiated; elevated humidity typically does not trigger fungal
may be considered confidential, or private, or both, in accor-
growth unless it is sustained),
dance with project contract, corporate protocol, or local, state,
6.2.2.4 air circulation and dehumidification (for example,
and federal regulations, or a combination thereof.
moisture may remained trapped when sealed behind
baseboards, attached furniture or vapor barriers).
5.8 It may be necessary to enlist other disciplines or trade
expertise to assist in some steps of the assessment, but
6.3 Detection of Fungal Growth:
recommendations of when to enlist and whom to enlist are
6.3.1 Fungus grows on an appropriate substrate. Fungal
beyond the scope of this guide.
growthisassociatedwithbiodegradablebuildingmaterials(for
example, paper covered gypsum wallboard, wood, ceiling
6. Background Information
tiles). It will not grow on inorganic materials (for example,
masonry, concrete, gypsum plaster, stone, glass, ceramic tiles,
6.1 Fungal Biology:
grout) except where dust, dirt, grease or oil is present. It
6.1.1 Fungal Growth—Fungi constitute over 25 % of the
usually appears on surfaces which are wet or were previously
earth’s biomass and are naturally present in every indoor and
wet.Fungalgrowthmaypre-existonwoodsurfacesnotsubject
outdoor environment. Fungal spores (small propagules emitted
to water damage on-site. For example, wood used for building
from surface growth) are ubiquitous in air and settled dust.
materials often becomes stained during tree growth or milling
Fungal growth requires sufficient available moisture that is
6.3.2 Fungal growth may be detected by simple visual
sustained for a sufficient time, a suitable food source/substrate,
inspection. Fungal growth may appear as raised, powdery
and a favorable range of temperature and pH. Both active and
deposits, rings or colored spots which may be black, gray,
inactive (past) growth are termed “colonization” (1, 5, 6).
white,green,red,resemblingcotton,velvet,leather,orpowder.
Fungi can become dormant only to resume growth again in
When rubbed, dried fungal growth tends to spread or smear as
response to changing environmental conditions (for example,
a powder.
during periodic moisture intrusions).
6.3.3 Discoloration is not necessarily fungal growth. The
6.1.2 Fungal Spore Production—Fungal spores are pro-
following surface markings should not be categorized as
duced during active growth, but may be released into the air
suspect fungal growth: yellow/brown water stains, scuffs, soot,
either during active growth or dormancy.Where fungal growth
dye, dust, ghosting (dust deposits form an outline on a cool
is located behind a wall, wall covering, ceiling, or carpet,
surface), efflorescence, adhesives, and other residues of
spores may, but are less likely to reach the occupied space
occupancy, maintenance, or construction.
through this physical barrier (the potential for infiltration
6.3.4 Visual detection of fungal growth is not always defini-
dependsonpressuredifferentials,filtration,occupantactivities,
tive. Where the origin of discoloration or staining is not clearly
barrier openings and other pathways, etc.) (7, 8, 9, 28).
fungal or non-fungal to the investigator, the discoloration
6.1.3 Fungal Variation—Types and concentrations of air-
should be considered suspect fungal growth. In some cases, an
borne or surface fungal spores at a given site as well as
ambiguous appearance may be resolved by comparing the
colonization vary substantially as they are influenced by many
suspect surface with the same material which has not been
natural and manmade factors. Because of this variability,
subjected to wetting to determine if the suspect color or texture
testing based on a limited number of samples may not be
waspre-existing.Ifessentia
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