1、Designation: D7338 10Standard Guide forAssessment Of Fungal Growth in Buildings1This standard is issued under the fixed designation D7338; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in paren
2、theses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide provides a compendium of information and amenu of options for assessment of fungal growth in buildings,but does not recommend a specific co
3、urse of action. Due to thewide variety of fungal problems affecting buildings and theiroccupants, and the wide variety of buildings, it is not possibleto describe a set of uniform steps that will always be performedduring an assessment (that is, a standard practice); therefore theuser of this guide
4、must decide which steps are appropriate fora given situation or building.1.2 This guide is specific to fungal growth, which is onlyone potential problem in a building environment. It may be partof, but is not intended to take the place of, a comprehensiveindoor air quality investigation.1.3 This gui
5、de describes minimum steps and procedures forcollecting background information on a building in question,procedures for evaluating the potential for moisture infiltrationor collection, procedures for inspection for suspect fungalgrowth, and procedures beyond the scope of a basic survey thatmay be us
6、eful for specific problems.1.4 Assessments for fungal growth may be useful whereverfungal growth is suspected, excess moisture has been presentor when there are concerns regarding potential fungal growth.1.5 Periodic fungal assessment in buildings may be acomponent of preventative maintenance progra
7、ms.1.6 This guide is applicable to buildings including residen-tial (for example, single or multi-family), institutional (forexample, schools, hospitals), government, public assembly,commercial (for example, office, retail), and industrial facili-ties.1.7 Recommendations for developing a sampling st
8、rategy ormethods for the collection and analysis of fungal samples arebeyond the scope of this guide. For recommendations fordeveloping a sampling strategy, see Ref (27)2, Chapter 10.1.8 Recommendations for remediation of fungal growth arebeyond the scope of this guide.1.9 This guide is not intended
9、 to supersede any governmentregulations governing the assessment of fungal growth inbuildings.1.10 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health pr
10、actices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3C755 Practice for Selection of Water Vapor Retarders forThermal InsulationC1699 Test Method for Moisture Retention Curves ofPorous Building Materials Using Pressure PlatesD653 T
11、erminology Relating to Soil, Rock, and ContainedFluidsD4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Base MaterialsE331 Test Method for Water Penetration of Exterior Win-dows, Skylights, Doors, and Curtain Walls by UniformStatic Air Pressure DifferenceE547 Test Method f
12、or Water Penetration of Exterior Win-dows, Skylights, Doors, and Curtain Walls by Cyclic StaticAir Pressure DifferenceE631 Terminology of Building ConstructionsE1105 Test Method for Field Determination of Water Pen-etration of Installed Exterior Windows, Skylights, Doors,and Curtain Walls, by Unifor
13、m or Cyclic Static AirPressure DifferenceE1186 Practices for Air Leakage Site Detection in BuildingEnvelopes and Air Barrier SystemsE1356 Test Method for Assignment of the Glass TransitionTemperatures by Differential Scanning CalorimetryE2128 Guide for Evaluating Water Leakage of BuildingWallsE2270
14、Practice for Periodic Inspection of Building Facadesfor Unsafe Conditions1This guide is under the jurisdiction of ASTM Committee D22 on Air Qualityand is the direct responsibility of Subcommittee D22.08 on Sampling and Analysisof Mold.Current edition approved Dec. 1, 2010. Published January 2011. DO
15、I:10.1520/D7338-10.2The boldface numbers in parentheses refer to a list of references at the end ofthis standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the
16、 standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2.2 Non-ASTM Standards:ANSI/GEI Standard MMS1001 Mold and Moisture Man-agement Standard for New Construction3. Terminology3.1 Definit
17、ions:3.1.1 building envelope, nthe outer elements of a build-ing, both above and below ground, which divide the externalfrom the internal environments. Commonly included are exte-rior walls, windows, doors, roofs and subfloors. E6313.1.2 bulk sample, npiece or quantity of bulk material thathas been
18、selected by some sampling process. D6533.1.3 capillary action, n(or capillary migration), of water,movement of water induced by the force of molecular attrac-tion (surface tension) between the water and the material itcontacts. E6313.1.4 condensation, nthe process of converting a materialin the gase
19、ous phase to a liquid by decreasing temperature orby increasing pressure, or both. E13563.1.5 exposure, ncontact with a chemical, biological,physical, or other agent over a specified time period. E13563.1.6 moisture content, nmass of water retained in thespecimen divided by the dry mass of the speci
20、men. C16993.1.7 soot, nagglomerations of particles of carbon im-pregnated with tar, formed in the incomplete combustion ofcarbonaceous material. E13563.1.8 vapor retarder, na material or system that ad-equately impedes the transmission of water vapor underspecified conditions. E6313.2 Definitions of
21、 Terms Specific to This Standard:3.2.1 boroscope, ndevice for internal inspection of diffi-cult access locations such as wall cavities. Its long narrow tubecontains a telescope system with a number of relay lenses.Light is provided via the optical path or fiber bundles.3.2.2 effloresce, vprocess by
22、which water leaches solublesalts out of concrete or mortar for surface deposit. Alsoefflorescence, n, the name for these deposits.3.2.3 enzyme activity, nmeasure of the quantity of activeenzyme present. Enzyme activity is essential to metabolism.Specifically, beta-N-acetylhexosaminidase (NAHA) is an
23、 en-zyme present in all filamentous fungi, the measurement ofwhich has been shown to be directly proportional to the amountof fungal biomass (see (18, 28).3.2.4 fungus, n(pl. fungi) a kingdom of organisms includ-ing molds, mildews, mushrooms, yeasts and many parasites.These are important decomposers
24、 in ecosystems. Fungi aretypically multi-cellular fungi with filamentous vegetative hy-phae.3.2.5 fungal spore, ngeneral term for a reproductivestructure in fungi. The spore is the structure that may be usedfor dissemination and reproduction, and may be resistant toadverse environmental conditions.3
25、.2.6 hypha, n(pl. hyphae) tubular filament of fungalcells; the basic vegetative structure of the body of fungi(excluding yeasts).3.2.7 fungal growth, nvegetative portion of a fungus.3.2.8 infrared thermography, nthermal imaging, alsocalled thermography, is the production of non-contact infrared,or “
26、heat” pictures from which temperature measurements canbe made.3.2.9 remediation, nto correct a problem. Related tofungal contamination, remediation includes correcting thewater and moisture problems and the cleaning, removal, and/orreplacement of mold-damaged or -contaminated materials.3.2.10 therma
27、l bridging, na phenomenon that occurswhen heat is transferred at a substantially higher rate througha component, or assembly of components in a buildingenvelope, than through the surrounding envelope area.4. Summary of Guide4.1 This guide presents a framework for locating andevaluating suspect funga
28、l growth in buildings. Topics includebackground information, a basic assessment strategy andadditional or advanced procedures.4.2 Components of a basic assessment strategy may include(1) defining a scope of work, (2) collecting backgroundinformation on the building and building systems, (3) formu-la
29、tion of a hypothesis or hypotheses, (4) an on-site survey forfungi, moisture dynamics, and heating. ventilating and airconditioning (HVAC) operation, and (5) documentation andreporting. Every component of the basic assessment shownbelow may be considered optional, since even some of themost basic st
30、eps may not be needed for certain well-definedsituations.4.3 When the information from the basic assessment isinsufficient to support decision-making, additional proceduresfor a follow-up study may include: (1) characterizing sitemoisture in greater detail to assist in locating suspect fungalgrowth
31、and controlling excess moisture; (2) accessing surfaceslikely to harbor hidden fungal growth; and/or (3) sampling ifnecessary to test a specific hypothesis.5. Significance and Use5.1 This guide presents options for a systematic assessmentof fungal growth in buildings.5.2 This guide allows for site-s
32、pecific flexibility and profes-sional judgment in the choice of assessment procedures. It maynot be necessary to perform in its entirety the basic assessmentpresented below to resolve a particular problem, for example,where fungal growth is localized and the source and extent ofmoisture is readily o
33、bservable.5.3 Conversely, no matter how comprehensive the survey,all fungal growth may not be identified or located in a fungalassessment.5.4 Material removal or destructive investigation may beneeded to access suspect surfaces.5.5 Using the procedures described in this guide, the inves-tigator may
34、have obtained the data necessary to suggestspecific recommendations, for example, how to remediate theobserved fungal growth, or how to prevent further fungalgrowth, but those recommendations are beyond the scope ofthis guide.5.6 Precautions may be needed to protect the assessor andbuilding occupant
35、s where access may disturb fungal growth.D7338 1025.7 It is the users responsibility to protect information thatmay be considered confidential, or private, or both, in accor-dance with project contract, corporate protocol, or local, state,and federal regulations, or a combination thereof.5.8 It may
36、be necessary to enlist other disciplines or tradeexpertise to assist in some steps of the assessment, butrecommendations of when to enlist and whom to enlist arebeyond the scope of this guide.6. Background Information6.1 Fungal Biology:6.1.1 Fungal GrowthFungi constitute over 25 % of theearths bioma
37、ss and are naturally present in every indoor andoutdoor environment. Fungal spores (small propagules emittedfrom surface growth) are ubiquitous in air and settled dust.Fungal growth requires sufficient available moisture that issustained for a sufficient time, a suitable food source/substrate,and a
38、favorable range of temperature and pH. Both active andinactive (past) growth are termed “colonization” (1, 5, 6).Fungi can become dormant only to resume growth again inresponse to changing environmental conditions (for example,during periodic moisture intrusions).6.1.2 Fungal Spore ProductionFungal
39、spores are pro-duced during active growth, but may be released into the aireither during active growth or dormancy. Where fungal growthis located behind a wall, wall covering, ceiling, or carpet,spores may, but are less likely to reach the occupied spacethrough this physical barrier (the potential f
40、or infiltrationdepends on pressure differentials, filtration, occupant activities,barrier openings and other pathways, etc.) (7, 8, 9, 28).6.1.3 Fungal VariationTypes and concentrations of air-borne or surface fungal spores at a given site as well ascolonization vary substantially as they are influe
41、nced by manynatural and manmade factors. Because of this variability,testing based on a limited number of samples may not berepresentative (5, 6).6.2 Fungal Growth in a Building:6.2.1 Indoor fungal growth is generally observed on sur-faces subject to one or more of these conditions:6.2.1.1 condensat
42、ion;6.2.1.2 spills, leaks or floods;6.2.1.3 consistent wetting, such as from landscape sprin-klers;6.2.1.4 sustained elevated humidity;6.2.1.5 wicking due to capillary action from wet material.6.2.2 Whether or not fungal growth actually occurs isdependent on:6.2.2.1 substrate porosity (for example,
43、materials such ascarpet tack strip and conventional drywall are highly suscep-tible),6.2.2.2 moisture resistance (for example, some drywall,gypsum plaster and sheathing products are modified to resistmoisture or to limit water storage and/or are treated with ananti-microbial agent),6.2.2.3 moisture
44、duration (for example, leaks which aresingle events or intermittent may dry before fungal growth isinitiated; elevated humidity typically does not trigger fungalgrowth unless it is sustained),6.2.2.4 air circulation and dehumidification (for example,moisture may remained trapped when sealed behind b
45、ase-boards, attached furniture or vapor barriers).6.3 Detection of Fungal Growth:6.3.1 Fungus grows on an appropriate substrate. Fungalgrowth is associated with biodegradable building materials (forexample, paper covered gypsum wallboard, wood, ceilingtiles). It will not grow on inorganic materials
46、(for example,masonry, concrete, gypsum plaster, stone, glass, ceramic tiles,grout) except where dust, dirt, grease or oil is present. Itusually appears on surfaces which are wet or were previouslywet. Fungal growth may pre-exist on wood surfaces not subjectto water damage on-site. For example, wood
47、used for buildingmaterials often becomes stained during tree growth or milling6.3.2 Fungal growth may be detected by simple visualinspection. Fungal growth may appear as raised, powderydeposits, rings or colored spots which may be black, gray,white, green, red, resembling cotton, velvet, leather, or
48、 powder.When rubbed, dried fungal growth tends to spread or smear asa powder.6.3.3 Discoloration is not necessarily fungal growth. Thefollowing surface markings should not be categorized assuspect fungal growth: yellow/brown water stains, scuffs, soot,dye, dust, ghosting (dust deposits form an outli
49、ne on a coolsurface), efflorescence, adhesives, and other residues of occu-pancy, maintenance, or construction.6.3.4 Visual detection of fungal growth is not always defini-tive. Where the origin of discoloration or staining is not clearlyfungal or non-fungal to the investigator, the discolorationshould be considered suspect fungal growth. In some cases, anambiguous appearance may be resolved by comparing thesuspect surface with the same material which has not beensubjected to wetting to determine if the suspect color or texturewas pre-existing. If essential to t
