ASTM D7788-14(2023)

Standard Practice for Collection of Total Airborne Fungal Structures via Inertial Impaction Methodology

SIGNIFICANCE AND USE
4.1 This practice is intended for the collection of airborne fungal spores or fragments, or both, using inertial impaction.  
4.2 It is the responsibility of the user to assure that they are in compliance with all local, state and federal regulations governing the inspection of buildings for fungal colonization and the collection of associated samples.  
4.3 This practice is intended to provide the user with a basic understanding of the equipment, materials and instructions necessary to effectively collect air samples using an inertial impactor.  
4.4 This practice, when properly executed, may also be used for the evaluation of other types of airborne particles with the capturing characteristics appropriate for inertial impactor, and for which appropriate analytical methods exist. Such particles may include dust mites, skin cells, pollen, and other materials.
SCOPE
1.1 The purpose of this practice is to describe procedures for the collection of airborne fungal spores or fragments, or both, using inertial impaction sampling techniques.  
1.2 This practice is not intended to limit the user from the collection of other airborne particulates that may be of interest and captured through this technique.  
1.3 This practice presumes that the user has a fundamental understanding of field investigative techniques related to the scientific process, and sampling plan development and implementation. It is important to establish the related hypothesis to be tested and the supporting analytical methodology needed in order to identify the sampling media to be used and the laboratory conditions for analysis.  
1.4 This practice does not address the development of a formal hypothesis or the establishment of appropriate and defensible investigation and sampling objectives. It is presumed the investigator has the experience and knowledge base to address these issues.  
1.5 This practice does not provide the user sufficient information to allow for interpretation of the analytical results from sample collection. It is the user's responsibility to seek or obtain the information and knowledge necessary to interpret the sample results reported by the laboratory.  
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.7 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 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.

General Information

• Status: Published
• Publication Date: 31-Dec-2022
• ICS: 13.040.20 - Ambient atmospheres
• Technical Committee: D22 - Air Quality
• Drafting Committee: D22.08 - Assessment, Sampling, and Analysis of Microorganisms

Relations

• Refers: ASTM D3195/D3195M-10(2023) - Standard Practice for Rotameter Calibration
• Effective Date: 01-Sep-2023
• Refers: ASTM D1356-20a - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Sep-2020
• Refers: ASTM D1356-20 - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 15-Mar-2020
• Refers: ASTM D7391-20 - Standard Test Method for Categorization and Quantification of Airborne Fungal Structures in an Inertial Impaction Sample by Optical Microscopy
• Effective Date: 15-Mar-2020
• Refers: ASTM D4840-99(2018)e1 - Standard Guide for Sample Chain-of-Custody Procedures
• Effective Date: 15-Aug-2018
• Refers: ASTM D7391-17 - Standard Test Method for Categorization and Quantification of Airborne Fungal Structures in an Inertial Impaction Sample by Optical Microscopy
• Effective Date: 15-Mar-2017
• Refers: ASTM D7391-17e1 - Standard Test Method for Categorization and Quantification of Airborne Fungal Structures in an Inertial Impaction Sample by Optical Microscopy
• Effective Date: 15-Mar-2017
• Refers: ASTM D1356-15a - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 15-Oct-2015
• Refers: ASTM D1356-15 - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Jul-2015
• Refers: ASTM D3195/D3195M-10(2015) - Standard Practice for Rotameter Calibration
• Effective Date: 01-Apr-2015
• Refers: ASTM D1356-14b - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Dec-2014
• Refers: ASTM D1356-14a - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-May-2014
• Refers: ASTM D1356-14 - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 15-Jan-2014
• Refers: ASTM D3195/D3195M-10 - Standard Practice for Rotameter Calibration
• Effective Date: 15-Jun-2010
• Refers: ASTM D1356-05(2010) - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Apr-2010

Overview

ASTM D7788-14(2023), Standard Practice for Collection of Total Airborne Fungal Structures via Inertial Impaction Methodology, is a globally recognized ASTM standard developed for the collection of airborne fungal spores and fragments. Using inertial impaction, this practice provides guidance on the effective sampling of air for assessing fungi-related contamination in various environments. The standard is essential for professionals involved in indoor air quality assessments, environmental health, and the evaluation of fungal colonization in buildings.

This standard ensures that sampling is consistent, scientifically sound, and supports compliance with local, state, and federal regulations concerning mold and indoor air quality investigations. It also extends to the evaluation of other airborne particles when appropriate analytical methods are available, making it versatile for broader bioaerosol investigations.

Key Topics

• Inertial Impaction Sampling: Guidance on using inertial impactor devices designed to collect airborne fungal structures by separating them from the air via inertia onto a collection surface.
• Sampling Equipment and Calibration:
  • Requirements for proper sampling assemblies, including cassettes or slides, pumps/fans, tubing, and calibration devices.
  • Procedures for calibrating and verifying airflow rates using primary and secondary calibration devices to ensure accurate sample volumes.
• Field Procedures:
  • Instructions for the setup and operation of sampling assemblies.
  • Sample identification, labeling, and the maintenance of chain-of-custody documentation.
  • Recording environmental conditions and sampling parameters (e.g., temperature, humidity, airflow).
• Sample Submission and Documentation:
  • Guidelines for properly handling, transporting, and submitting samples for laboratory analysis.
  • Details regarding field data sheet requirements, sample identification, and custody transfer protocols.
• Limitations and Responsibilities:
  • Users are expected to have foundational knowledge of investigative and sampling techniques.
  • The standard does not provide instructions for hypothesis development or analytical result interpretation; users must obtain this expertise separately.
  • Emphasizes safety, regulatory compliance, and awareness of limitations inherent to sampling airborne particles.

Applications

ASTM D7788-14(2023) is widely applied across multiple sectors, particularly in the fields of:

• Indoor Air Quality Assessment: Sampling for airborne fungal spores and fragments in residential, commercial, and institutional buildings to evaluate potential mold issues and health risks.
• Environmental Health and Safety: Used by occupational health professionals and industrial hygienists for routine inspections and after water damage events.
• Regulatory Compliance: Assists organizations in meeting local, state, and federal requirements concerning mold inspections and the collection of bioaerosol samples.
• Research: Employed for scientific studies related to fungal exposure, airborne particulate characterization, and environmental contamination.
• Broader Bioaerosol Sampling: While centered on fungal structures, the methodology can be adapted for the collection of pollen, dust mites, skin cells, and similar particulates when appropriate analytical techniques are available.

Related Standards

For comprehensive air sampling and analysis, ASTM D7788-14(2023) references and complements several related ASTM standards:

• ASTM D1356: Terminology Relating to Sampling and Analysis of Atmospheres
• ASTM D3195/D3195M: Practice for Rotameter Calibration
• ASTM D4840: Guide for Sample Chain-of-Custody Procedures
• ASTM D6044: Guide for Representative Sampling for Management of Waste and Contaminated Media
• ASTM D7391: Test Method for Categorization and Quantification of Airborne Fungal Structures in an Inertial Impaction Sample by Optical Microscopy

These standards collectively support best practices for accurate airborne particle sampling, reliable documentation, and consistent calibration, helping ensure high-quality results in indoor air quality investigations and broader environmental assessments.

For more information or to obtain these standards, visit the ASTM International website.

Standards Content (Sample)

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.
Designation: D7788 − 14 (Reapproved 2023)
Standard Practice for
Collection of Total Airborne Fungal Structures via Inertial
Impaction Methodology
This standard is issued under the fixed designation D7788; 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 ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.1 The purpose of this practice is to describe procedures for
mendations issued by the World Trade Organization Technical
the collection of airborne fungal spores or fragments, or both,
Barriers to Trade (TBT) Committee.
using inertial impaction sampling techniques.
1.2 This practice is not intended to limit the user from the
2. Referenced Documents
collection of other airborne particulates that may be of interest
2.1 ASTM Standards:
and captured through this technique.
D1356 Terminology Relating to Sampling and Analysis of
1.3 This practice presumes that the user has a fundamental
Atmospheres
understanding of field investigative techniques related to the
D3195/D3195M Practice for Rotameter Calibration
scientific process, and sampling plan development and imple-
D4840 Guide for Sample Chain-of-Custody Procedures
mentation. It is important to establish the related hypothesis to
D6044 Guide for Representative Sampling for Management
be tested and the supporting analytical methodology needed in
of Waste and Contaminated Media
order to identify the sampling media to be used and the
D7391 Test Method for Categorization and Quantification of
laboratory conditions for analysis.
Airborne Fungal Structures in an Inertial Impaction
Sample by Optical Microscopy
1.4 This practice does not address the development of a
formal hypothesis or the establishment of appropriate and
3. Terminology
defensible investigation and sampling objectives. It is pre-
sumed the investigator has the experience and knowledge base
3.1 Definitions—For definitions and terms not listed here,
to address these issues.
see Terminology D1356.
1.5 This practice does not provide the user sufficient infor- 3.1.1 inertial impactor, n—a device designed for the impac-
mation to allow for interpretation of the analytical results from tion of particles that are separated from the air stream by inertia
sample collection. It is the user’s responsibility to seek or onto a collection surface. D7391
obtain the information and knowledge necessary to interpret 3.1.1.1 Discussion—Inertial impactors are available in
the sample results reported by the laboratory. many designs including “slit” and “circular” jets.
3.1.1.2 Discussion—Allows for the identification to genus
1.6 The values stated in SI units are to be regarded as
or group of fungi detected, quantification to spores/m , and
standard. No other units of measurement are included in this
general assessment of background debris. Identification of
standard.
pollen, hyphal fragments and other airborne particulate may be
1.7 This standard does not purport to address all of the
included.
safety concerns, if any, associated with its use. It is the
3.1.2 sample, n—a portion of a population. A portion of
responsibility of the user of this standard to establish appro-
material that is taken for testing or record purposes. D6044
priate safety, health, and environmental practices and deter-
3.1.3 sample, representative, n—a sample collected in such
mine the applicability of regulatory limitations prior to use.
a manner that it reflects one or more characteristics of interest
1.8 This international standard was developed in accor-
(as defined by the project objectives) of a population from
dance with internationally recognized principles on standard-
which it is collected. D6044
This practice is under the jurisdiction of ASTM Committee D22 on Air Quality
and is the direct responsibility of Subcommittee D22.08 on Assessment, Sampling,
and Analysis of Microorganisms. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Jan. 1, 2023. Published February 2023. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2014. Last previous edition approved in 2014 as D7788 – 14. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D7788-14R23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7788 − 14 (2023)
3.1.3.1 Discussion—Populations of airborne fungal spores 4.4 This practice, when properly executed, may also be used
are typically not homogeneous. for the evaluation of other types of airborne particles with the
capturing characteristics appropriate for inertial impactor, and
3.2 Definitions of Terms Specific to This Standard:
for which appropriate analytical methods exist. Such particles
3.2.1 aerodynamic diameter (d ), n—the diameter of a unit
a
may include dust mites, skin cells, pollen, and other materials.
density sphere having the same inertial properties as the
particle under analysis under the same conditions.
5. Preparation of Sampling Equipment
3.2.1.1 Discussion—For fungal spores this is generally
based on a water droplet, (spherical particle) having a density
5.1 Equipment List:
of 1 g/cm . Aerodynamic diameter has been developed to
5.1.1 Sampling Assembly—The combination of components
categorize the sizes of particles of different shapes and densi-
from the pump/fan system through to the sampling media (for
ties with a single dimension. The aerodynamic diameter is not
example cassette, slide) including any transport tubing, flow
necessarily equal to the physical diameter due to variations in
controller and connectors. The configuration may be an inte-
shape or density.
grated assembly or components that have been configured with
3.2.2 calibration impactor, n—a designated cassette, or an external pump/fan.
media unit, placed in the sampling assembly during calibration
NOTE 1—Rotary vane, diaphragm, linear magnetic, piston and fan
or verification of the air flow rate.
driven devices may have the open flow capacity for specific impactors;
however, resistance to flow through the impactor can dramatically reduce
3.2.3 chain of custody (COC) record, n—a document that
flow rates. Care must be taken to select a pump and calibrator that are
provides for the traceable transfer of field samples to the
compatible with impactors to set and measure flow rates properly.
analytical laboratory. It may or may not be combined with the
5.1.1.1 Use an inertial impactor with a d collection effi-
field data sheet.
ciency less than or equal to a 3.0 μm d in accordance with the
3.2.3.1 Discussion—Additional guidance can be found in
a
manufacturer’s recommended flow rate, sample time, and
Guide D4840.
sample orientation. Record these parameters.
3.2.4 collection or capture effıciency, n—the percentage of a
specified substance retained by a sampling device.
NOTE 2—Use collection efficiency data available from manufacturers’
technical reports or from peer-reviewed published data.
3.2.4.1 Discussion—Collection or capture efficiency is a
NOTE 3—All bioaerosol impactors operate on the same principles
function of the geometries of the impactors and the air flow
regardless of the operating parameters. However, all impactors are not
rate, the jet dimensions and jet to plate distance, and the
equally effective or efficient in trapping particles from an air stream.
aerodynamic diameters, shape, density and surface morphol-
Published data investigating some common fungi in airborne samples
ogy of the airborne particles.
discusses these differences and how they affect collection efficiency (2-5).
3.2.5 field data sheet, n—a record that provides a reference
5.1.1.2 For external pump/fan assemblies, use flexible tub-
document for information directly related to the sample col-
ing and connectors appropriate for secure connection of
lection event, including pre- and post-calibration data.
impactor to pump/fan.
3.2.6 fungal structure (sing.), n—a collective term for frag-
5.1.2 Primary flow calibration device with a measuring
ments or groups of fragments from fungi, including but not
range appropriate for the system and with a 65 % tolerance of
limited to conidia, conidiophores, hyphae and spores.
the desired flow rate.
5.1.3 Secondary flow calibration or verification device, for
3.2.7 fungus (sing.), fungi, (pl.), n—eukaryotic,
example, rotameter or other device used to check system
heterotrophic, absorptive organisms that usually develop a
performance in the field.
rather diffuse, branched, tubular body (that is, network of
hyphae) and usually reproduce by means of spores (1). The 5.1.4 Stop watch or other timing device capable of measur-
terms ‘mold’ and ‘mildew’ are frequently used by laypersons ing time in increments of minutes and seconds (one second
when referring to various fungal colonization. resolution).
5.1.5 Field data sheet. Refer to 6.6.
4. Significance and Use
5.1.6 Support stand (optional). Allows for consistent
4.1 This practice is intended for the collection of airborne
sample collection height.
fungal spores or fragments, or both, using inertial impaction.
5.2 Assembly Calibration:
4.2 It is the responsibility of the user to assure that they are
5.2.1 Calibra
...