1、Designation: D7338 14Standard 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 (1)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 pra
10、ctices 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 of Po-rous Building Materials Using Pressure PlatesD653
11、Terminology 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 ExteriorWindows, Skylights, Doors, and Curtain Walls by Uni-form Static Air Pressure DifferenceE547 Test Method
12、for Water Penetration of ExteriorWindows, Skylights, Doors, and Curtain Walls by CyclicStatic Air 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 Uniform
13、 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 BuildingWalls1This g
14、uide 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 June 1, 2014. Published July 2014. Originally approvedin 2010. Last previous edition approved in 2010 as D7338 10. DOI:1
15、0.1520/D7338-14.2The 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 st
16、andards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1E2270 Practice for Periodic Inspection of Building Facadesfor Unsafe Conditions2.2 Non-ASTM Standards:ANSI/GEI Standard MMS1001 Mold and
17、Moisture Man-agement Standard for New Construction3. Terminology3.1 Definitions:3.1.1 building envelope, nthe outer elements of abuilding, both above and below ground, which divide theexternal from the internal environments. Commonly includedare exterior walls, windows, doors, roofs and subfloors. E
18、6313.1.2 bulk sample, npiece or quantity of bulk material thathas been 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. E
19、6313.1.4 condensation, nthe process of converting a materialin the gaseous 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, nmas
20、s of water retained in thespecimen divided by the dry mass of the specimen. C16993.1.7 soot, nagglomerations of particles of carbon impreg-nated with tar, formed in the incomplete combustion ofcarbonaceous material. E13563.1.8 vapor retarder, na material or system that ad-equately impedes the transm
21、ission of water vapor underspecified conditions. E6313.2 Definitions of 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 provid
22、ed via the optical path or fiber bundles.3.2.2 effloresce, vprocess by 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 essenti
23、al to metabolism.Specifically, beta-N-acetylhexosaminidase (NAHA) is an en-zyme present in all filamentous fungi, the measurement ofwhich has been shown to be directly proportional to the amountof fungal biomass (see (2, 3).3.2.4 fungus (s), fungi (pl.), neukaryotic, heterotrophic,absorptive organis
24、ms that usually develop a rather diffuse,branched, tubular body (that is, network of hyphae) and usuallyreproduce by means of spores (4). The terms mold andmildew are frequently used by laypersons when referring tovarious fungal colonization.3.2.5 fungal spore, ngeneral term for a reproductivestruct
25、ure in fungi. The spore is the structure that may be usedfor dissemination and reproduction, and may be resistant toadverse environmental conditions.3.2.6 hypha, n(pl. hyphae) tubular filament of fungalcells; the basic vegetative structure of the body of fungi(excluding yeasts).3.2.7 fungal growth,
26、nvegetative portion of a fungus.3.2.8 infrared thermography, nthermal imaging, alsocalled thermography, is the production of non-contact infrared,or “heat” pictures from which temperature measurements canbe made.3.2.9 remediation, nto correct a problem. Related tofungal contamination, remediation in
27、cludes correcting thewater and moisture problems and the cleaning, removal, and/orreplacement of mold-damaged or -contaminated materials.3.2.10 thermal bridging, na phenomenon that occurswhen heat is transferred at a substantially higher rate througha component, or assembly of components in a buildi
28、ngenvelope, than through the surrounding envelope area.4. Summary of Guide4.1 This guide presents a framework for locating andevaluating suspect fungal growth in buildings. Topics includebackground information, a basic assessment strategy andadditional or advanced procedures.4.2 Components of a basi
29、c assessment strategy may include(1) defining a scope of work, (2) collecting backgroundinformation on the building and building systems, (3) formu-lation of a hypothesis or hypotheses, (4) an on-site survey forfungi, moisture dynamics, and heating. ventilating and airconditioning (HVAC) operation,
30、and (5) documentation andreporting. Every component of the basic assessment shownbelow may be considered optional, since even some of themost basic steps may not be needed for certain well-definedsituations.4.3 When the information from the basic assessment isinsufficient to support decision-making,
31、 additional proceduresfor a follow-up study may include: (1) characterizing sitemoisture in greater detail to assist in locating suspect fungalgrowth and controlling excess moisture; (2) accessing surfaceslikely to harbor hidden fungal growth; and/or (3) sampling ifnecessary to test a specific hypot
32、hesis.5. Significance and Use5.1 This guide presents options for a systematic assessmentof fungal growth in buildings.5.2 This guide allows for site-specific flexibility and profes-sional judgment in the choice of assessment procedures. It maynot be necessary to perform in its entirety the basic ass
33、essmentpresented below to resolve a particular problem, for example,where fungal growth is localized and the source and extent ofmoisture is readily observable.5.3 Conversely, no matter how comprehensive the survey,all fungal growth may not be identified or located in a fungalassessment.5.4 Material
34、 removal or destructive investigation may beneeded to access suspect surfaces.D7338 1425.5 Using the procedures described in this guide, the inves-tigator may have obtained the data necessary to suggestspecific recommendations, for example, how to remediate theobserved fungal growth, or how to preve
35、nt further fungalgrowth, but those recommendations are beyond the scope ofthis guide.5.6 Precautions may be needed to protect the assessor andbuilding occupants where access may disturb fungal growth.5.7 It is the users responsibility to protect information thatmay be considered confidential, or pri
36、vate, or both, in accor-dance with project contract, corporate protocol, or local, state,and federal regulations, or a combination thereof.5.8 It may be necessary to enlist other disciplines or tradeexpertise to assist in some steps of the assessment, butrecommendations of when to enlist and whom to
37、 enlist arebeyond the scope of this guide.6. Background Information6.1 Fungal Biology:6.1.1 Fungal GrowthFungi constitute over 25 % of theearths biomass and are naturally present in every indoor andoutdoor environment. Fungal spores (small propagules emittedfrom surface growth) are ubiquitous in air
38、 and settled dust.Fungal growth requires sufficient available moisture that issustained for a sufficient time, a suitable food source/substrate,and a favorable range of temperature and pH. Both active andinactive (past) growth are termed “colonization” (5, 6, 7).Fungi can become dormant only to resu
39、me growth again inresponse to changing environmental conditions (for example,during periodic moisture intrusions).6.1.2 Fungal Spore ProductionFungal spores are pro-duced during active growth, but may be released into the aireither during active growth or dormancy. Where fungal growthis located behi
40、nd a wall, wall covering, ceiling, or carpet,spores may, but are less likely to reach the occupied spacethrough this physical barrier (the potential for infiltrationdepends on pressure differentials, filtration, occupant activities,barrier openings and other pathways, etc.) (8, 9, 10, 3).6.1.3 Funga
41、l VariationTypes and concentrations of air-borne or surface fungal spores at a given site as well ascolonization vary substantially as they are influenced by manynatural and manmade factors. Because of this variability,testing based on a limited number of samples may not berepresentative (6, 7).6.2
42、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 condensation;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
43、 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, materials such ascarpet tack strip and conventional drywall are highlysusceptible),6.2.2.2 moisture resistance (for example, some drywall,gypsum plast
44、er 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 duration (for example, leaks which aresingle events or intermittent may dry before fungal growth isinitiated; elevated humidity typically does not trigg
45、er fungalgrowth unless it is sustained),6.2.2.4 air circulation and dehumidification (for example,moisture may remained trapped when sealed behindbaseboards, attached furniture or vapor barriers).6.3 Detection of Fungal Growth:6.3.1 Fungus grows on an appropriate substrate. Fungalgrowth is associate
46、d with biodegradable building materials (forexample, paper covered gypsum wallboard, wood, ceilingtiles). It will not grow on inorganic materials (for example,masonry, concrete, gypsum plaster, stone, glass, ceramic tiles,grout) except where dust, dirt, grease or oil is present. Itusually appears on
47、 surfaces which are wet or were previouslywet. Fungal growth may pre-exist on wood surfaces not subjectto water damage on-site. For example, wood used for buildingmaterials often becomes stained during tree growth or milling6.3.2 Fungal growth may be detected by simple visualinspection. Fungal growt
48、h may appear as raised, powderydeposits, rings or colored spots which may be black, gray,white, green, red, resembling cotton, velvet, leather, or powder.When rubbed, dried fungal growth tends to spread or smear asa powder.6.3.3 Discoloration is not necessarily fungal growth. Thefollowing surface ma
49、rkings should not be categorized assuspect fungal growth: yellow/brown water stains, scuffs, soot,dye, dust, ghosting (dust deposits form an outline on a coolsurface), efflorescence, adhesives, and other residues ofoccupancy, 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
