ASTM F1977-04(2017)
(Test Method)Standard Test Method for Determining Initial, Fractional, Filtration Efficiency of a Vacuum Cleaner System
Standard Test Method for Determining Initial, Fractional, Filtration Efficiency of a Vacuum Cleaner System
SIGNIFICANCE AND USE
5.1 It is well known that modern electrical appliances, incorporating electric motors that use carbon brushes for commutation, may emit aerosolized, particles into the surrounding environment. This test method determines the initial, fractional, filtration efficiency of a vacuum cleaner system, taking those emissions into consideration.
5.2 For all vacuum cleaner systems tested, the total emissions of the unit, whatever the source(s), will be counted at each of the six particle size levels identified in the test procedure. This test method determines the initial, fractional filtration efficiency of a vacuum cleaner system, with or without the motor emissions mathematically removed in the calculation of efficiency.
SCOPE
1.1 This test method may be used to determine the initial, fractional, filtration efficiency of household and commercial canister (tank-type), stick, hand-held, upright, and utility vacuum cleaner systems.
1.1.1 Water-filtration vacuum cleaners which do not utilize a replaceable dry media filter located between the water-based filter and cleaning air exhaust are not included in this test method. It has been determined that the exhaust of these vacuum cleaners is not compatible with the specified discrete particle counter (DPC) procedure.
1.2 The initial, fractional, filtration efficiencies of the entire vacuum cleaner system, at six discrete particle sizes (0.3, 0.5, 0.7, 1.0, 2.0, and >3 μm), is derived by counting upstream challenge particles and the constituent of downstream particles while the vacuum cleaner system is being operated in a stationary test condition.
1.3 The vacuum cleaner system is tested at the nozzle with the normal airflow rate produced by restricting the inlet to the nozzle adapter with the 11/4-in. orifice.
1.4 The vacuum cleaner system is tested with a new filter(s) installed, and with no preliminary dust loading. The fractional efficiencies determined by this test method shall be considered initial system filtration efficiencies. The filters are not changed between test runs on the same cleaner.
1.5 Neutralized potassium chloride (KCl) is used as the challenge media in this test method.
1.6 One or two particle counters may be used to satisfy the requirements of this test method. If using one counter, flow control is required to switch between sampling the upstream and downstream air sampling probes.
1.7 To efficiently utilize this test method, automated test equipment and computer automation is recommended.
1.8 Different sampling parameters, flow rates, and so forth, for the specific applications of the equipment and test procedure may provide equivalent results. It is beyond the scope of this test method to define those various possibilities.
1.9 This test method is limited to the test apparatus, or its equivalent, as described in this document.
1.10 This test method is not intended or designed to provide any measure of the health effects or medical aspects of vacuum cleaning.
1.11 This test method is not intended or designed to determine the integrity of HEPA filtration assemblies used in vacuum cleaner systems employed in nuclear and defense facilities.
1.12 The inch-pound system of units is used in this test method, except for the common usage of the micrometer, μm, for the description of particle size which is a SI unit.
1.13 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: F1977 − 04 (Reapproved 2017)
Standard Test Method for
Determining Initial, Fractional, Filtration Efficiency of a
Vacuum Cleaner System
This standard is issued under the fixed designation F1977; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope dure may provide equivalent results. It is beyond the scope of
this test method to define those various possibilities.
1.1 This test method may be used to determine the initial,
fractional, filtration efficiency of household and commercial
1.9 This test method is limited to the test apparatus, or its
canister (tank-type), stick, hand-held, upright, and utility
equivalent, as described in this document.
vacuum cleaner systems.
1.10 Thistestmethodisnotintendedordesignedtoprovide
1.1.1 Water-filtration vacuum cleaners which do not utilize
anymeasureofthehealtheffectsormedicalaspectsofvacuum
a replaceable dry media filter located between the water-based
cleaning.
filter and cleaning air exhaust are not included in this test
method. It has been determined that the exhaust of these
1.11 This test method is not intended or designed to
vacuum cleaners is not compatible with the specified discrete
determine the integrity of HEPA filtration assemblies used in
particle counter (DPC) procedure.
vacuum cleaner systems employed in nuclear and defense
1.2 The initial, fractional, filtration efficiencies of the entire facilities.
vacuum cleaner system, at six discrete particle sizes (0.3, 0.5,
1.12 The inch-pound system of units is used in this test
0.7, 1.0, 2.0, and >3 µm), is derived by counting upstream
method, except for the common usage of the micrometer, µm,
challengeparticlesandtheconstituentofdownstreamparticles
for the description of particle size which is a SI unit.
while the vacuum cleaner system is being operated in a
1.13 This standard does not purport to address all of the
stationary test condition.
safety concerns, if any, associated with its use. It is the
1.3 The vacuum cleaner system is tested at the nozzle with
responsibility of the user of this standard to establish appro-
the normal airflow rate produced by restricting the inlet to the
priate safety and health practices and determine the applica-
nozzle adapter with the 1 ⁄4-in. orifice.
bility of regulatory limitations prior to use.
1.4 Thevacuumcleanersystemistestedwithanewfilter(s)
installed, and with no preliminary dust loading. The fractional
2. Referenced Documents
efficiencies determined by this test method shall be considered
2.1 ASTM Standards:
initial system filtration efficiencies. The filters are not changed
D1193Specification for Reagent Water
between test runs on the same cleaner.
D1356Terminology Relating to Sampling and Analysis of
1.5 Neutralized potassium chloride (KCl) is used as the
Atmospheres
challenge media in this test method.
D3154Test Method for Average Velocity in a Duct (Pitot
1.6 One or two particle counters may be used to satisfy the
Tube Method)
requirements of this test method. If using one counter, flow
F50Practice for Continuous Sizing and Counting of Air-
control is required to switch between sampling the upstream
borne Particles in Dust-Controlled Areas and Clean
and downstream air sampling probes.
Rooms Using Instruments Capable of Detecting Single
Sub-Micrometre and Larger Particles
1.7 To efficiently utilize this test method, automated test
F395Terminology Relating to Vacuum Cleaners
equipment and computer automation is recommended.
F558Test Method for Measuring Air Performance Charac-
1.8 Different sampling parameters, flow rates, and so forth,
teristics of Vacuum Cleaners
for the specific applications of the equipment and test proce-
ThistestmethodisunderthejurisdictionofASTMCommitteeF11onVacuum
Cleaners and is the direct responsibility of Subcommittee F11.23 on Filtration. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 1, 2017. Published March 2017. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1999. Last previous edition approved in 2010 as F1977 – 04 (2010). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/F1977-04R17. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1977 − 04 (2017)
3.1.7 primary motor(s), n—the motor(s) which drive(s) the
blower(s), producing airflow through the vacuum cleaner.
3.1.8 secondary motor(s), n—the motor(s) in the vacuum
cleaner system not employed for the generation of airflow.
3.1.9 sheath air, n—the air flowing over and around the test
unit that is mounted in the test chamber.
3.1.10 stabilization, n—those conditions of operation which
FIG. 1 Nozzle Adapter
produce results having a total variation of less than 3% and at
least 1000 total count in all size ranges for challenge equal to
or less than 15 counts per cubic foot in the 0.3-µm channel for
2.2 Other Documents:
the background count.
IES Recommended Practice CC021.1Testing HEPA and
3 3.1.10.1 Discussion—Total variation is calculated as the
ULPA Filter Media
maximumdatapointminustheminimumdatapointdividedby
IES Recommended Practice CC001.3HEPA and ULPA
3 the maximum data point times 100.
Filters
3.1.10.2 Discussion—The assurance of statistical control is
ISO Guide 25General Requirements for the Competence of
not a simple matter and needs to be addressed.Aprocess is in
Calibration and Testing Laboratories
a state of statistical control if the variations between the
EN 1822High Efficiency Air Filters (HEPA and ULPA)
observedtestresultsvaryinapredictablemannerandshowno
unassignable trends, cyclical characteristics, abrupt changes,
3. Terminology
excess scatter, or other unpredictable variations.
3.1 Definitions of Terms Specific to This Standard:
3.1.1 challenge, n—aerosolized media introduced upstream
3.1.11 system filtration effıciency, n—a numerical value
of the test unit and used to determine the filtration character-
based on the ratio of a discrete size, particle count emerging
istics of the test unit.
from the vacuum cleaner, relative to the upstream challenge,
3.1.1.1 Discussion—Also known as test aerosol. The term
particle count of the same size.
“contaminant” shall not be used to describe the media or
3.1.12 test chamber, n—the enclosed space surrounding the
aerosol used to challenge the filtration system in this test
vacuum cleaner being tested, used to maintain the controlled
method. The term “contaminant” is defined in Terminology
environmental conditions required during the test procedure.
D1356 and does not meet the needs of this test method.
3.1.13 test run, n—the definitive procedure that produces a
3.1.2 chamber airflow, n—the sum of all airflows measured
singular measured result.
at a point near the downstream probe.
3.1.13.1 Discussion—Atest run is the period of time during
3.1.3 filter, n—the entity consisting of the converted filter
which one complete set of upstream or downstream air sample
media and other items required to be employed in a vacuum
data, or both, is acquired.
cleaner for the purpose of arresting and collecting particulate
3.2 Definitions:
matter from the dirt-laden air stream; sometimes referred to as
a filter element, filter assembly, cartridge, or bag. 3.2.1 aerosol, n—a suspension of solid or liquid particles in
a gas.
3.1.4 normal airflow, n—that airflow occurring at the sys-
tem’s nozzle due to the 1 ⁄4-in. orifice restriction at the inlet to
3.2.2 background particles, n—extraneous particles in the
the nozzle adapter.
air stream prior to the start of the test.
3.1.5 nozzle adaptor, n—a plenum chamber, fabricated to
3.2.2.1 Discussion—Under conditions required of this test
mount to the inlet nozzle of the test unit in a sealable manner
method, extraneous particles will be found to pass through the
and shown in Fig. 1.
test chamber (for example, particles penetrating the test cham-
3.1.5.1 Discussion—Construction specifications are dis-
ber’s HEPA filters or being abraded or released from the
cussed in the Apparatus section.
surfaces of tubing and test equipment). Operating under
stabilized conditions, these particles shall be counted in the
3.1.6 particle count, n—the numeric sum of particles per
downstream flow and subsequently subtracted from the test
cubic foot over the specified sample time.
data to determine the initial, fractional, filtration efficiency of
3.1.6.1 Discussion—Throughout this test method, the units
the test unit (see Note 3).
ofmeasureforthisterm,generally,donotaccompanytheterm
“particle count” and are assumed to be understood by the
3.2.3 channel, n—in particle analyzers, a group of particle
reader.
sizes having a definitive range; the lower end of the range
identifies the channel, for example, a range of particle sizes
from 0.3 to 0.5 µm is identified as the 0.3-µm channel.
Available from Institute of Environmental Sciences and Technology (IEST),
Arlington Place One, 2340 S.Arlington Heights Rd., Suite 100,Arlington Heights,
3.2.4 coincidence error, n—in particle analyzers, errors
IL 60005-4516, http://www.iest.org.
occurring at concentration levels near or above the design
Available from International Organization for Standardization (ISO), 1, ch. de
limits of the instrument being used because two or more
la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http://
www.iso.ch. particles are simultaneously being sensed.
F1977 − 04 (2017)
3.2.5 diffusion dryer, n—in aerosol technology, a device Krypton gas, Kr-85, sealed in a stainless steel tube shielded by
containing desiccant, surrounding the aerosol flow path, that an outer metal housing.
removes excess moisture by diffusion capture.
3.2.14 particle, n—a small, discrete object.
3.2.6 diluter, n—in aerosol technology, a device used to
3.2.15 particulate, adj—indicates that the material in ques-
reduce the concentration of particles in an aerosol.
tion has particle-like properties.
3.2.7 downstream, adv—signifies the position of any object
3.2.16 population, n—thetotalofalltheunitsofaparticular
or condition that is physically in or part of the airflow stream
model vacuum cleaner being tested.
occurring after the referenced item.
3.2.17 sample, n—a small, representative group of vacuum
3.2.8 DPC, n—an acronym for discrete particle counter.
cleaners, taken from a large collection (population) of vacuum
3.2.8.1 Discussion—The IES Recommended Practice
cleaners of one particular model, which serve to provide
CC001.3 and Practice F50 describe a discrete particle counter
information that may be used as a basis for making a
as a instrument that utilizes light-scattering or other suitable
determination concerning the larger collection.
principle to count and size discrete particles in air, and that
3.2.18 submicrometer, adj—describes the range of particles
displays or records the results. The discrete particle counter is
–6
having a mean diameter of less than 1 µm (1 × 10 m).
also known as a single-particle counter or simply as a particle
3.2.19 unit or test unit, n—a single vacuum cleaner system
counter and it determines geometric rather than aerodynamic
of the model being tested.
particle size.
3.2.20 upstream, adv—signifiesthepositionofanyobjector
3.2.9 fractional effıciency, n—a numerical value based on
condition that is physically in or part of the airflow stream
the ratio of the number of emergent, downstream particles of a
occurring before the referenced item.
discrete size, relative to the number of incident, upstream
particles of the same size. 3.2.21 vacuum cleaner, n—as defined inTerminology F395.
3.2.9.1 Discussion—In practice, a single particle size is
3.3 Symbols:
reported, having an understood or assumed size range equal to
the channel size. This value is also known as the differential
cfm = cubic feet/minute.
size efficiency or particle size efficiency, or both. D = diameter, in.
ft = feet.
3.2.10 fractional effıciency curve, n—the fractional effi-
°F = degrees Fahrenheit.
ciency plotted as a function of the particle size.
Hz = frequency, Hertz.
3.2.11 HEPA, adj—an acronym for high-efficiency particu-
H O = water, column.
late air.
in. = inch.
3.2.11.1 Discussion—Additional information pertaining to
psi = pound-force per square inch.
HEPA may be found in IES 21.1 (99.97% at 0.3 µ in salt as Q = airflow rate, cubic feet/minute.
modified) or EN 1822 (H12 or better at 0.3 µ rather than most RH = relative humidity.
RMS = root mean square.
penetrating particle size).
s = second.
3.2.12 laminar, adj—in pneumatics, nonturbulent, laminar
¯
X = population mean.
flow through a pipe is considered laminar when the Reynolds
X = test unit average.
i
number is less than approximately 2000 and turbulent for a –6
µm = micrometre (10 m).
Reynolds number greater than approximately 4000.
% = percent.
3.2.12.1 Discussion—Laminar flow in a pipe is character-
ized by a smooth symmetrical pattern of streamlines. The
4. Summary of Test Method
Reynolds number is a nondimensional unit of measure propor-
4.1 This test method provides a procedure to determine the
tionaltotheratiooftheinertialforceofthegastothefrictional
6,7 initial, fractional, filtration efficiency of a vacuum cleaner
forces acting on each element of the fluid.
system (system filtration efficiency). The effects of the down-
3.2.13 neutralizer, n—in aerosol technology, a device used
streamconcentrationofparticlesthatmaybecausedbyvarious
to minimize losses and coagulation caused by electrostatic
factors including the electric motor(s) used in the vacuum
charges, and to counteract high charge levels in aerosols
cleanerarecountedaspartofthetestmethod.Thereportonthe
generated by nebulization, combustion, or dispersion by neu-
results of the testing will indicate if these downstream counts
tralizingtheparticlechargeleveltotheBoltzmanndistribution
were included or were mathematically removed in the deter-
level.
mination of the initial fractional efficiency.
3.2.13.1 Discussion—Neutralizers generally use radioactive
4.2 In determining a vacuum cleaner system’s initial,
fractional, filtration efficiency, the test unit is placed in a test
5 chamber, and sealed from ambient conditions. In this test
“High Efficiency Particulate Air Filters (HEPA and ULPA),” European Com-
chamber, a large, controlled volume of HEPA filtered air
mittee for Standardization (CEN), prEN 1822-1:1995, January 1995.
Hinds, William C., Aerosol Technology—Properties, Behavior, and Measure-
(meeting HEPA standa
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F1977 − 04 (Reapproved 2010) F1977 − 04 (Reapproved 2017)An American National Standard
Standard Test Method for
Determining Initial, Fractional, Filtration Efficiency of a
Vacuum Cleaner System
This standard is issued under the fixed designation F1977; 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
1.1 This test method may be used to determine the initial, fractional, filtration efficiency of household and commercial canister
(tank-type), stick, hand-held, upright, and utility vacuum cleaner systems.
1.1.1 Water-filtration vacuum cleaners which do not utilize a replaceable dry media filter located between the water-based filter
and cleaning air exhaust are not included in this test method. It has been determined that the exhaust of these vacuum cleaners is
not compatible with the specified discrete particle counter (DPC) procedure.
1.2 The initial, fractional, filtration efficiencies of the entire vacuum cleaner system, at six discrete particle sizes (0.3, 0.5, 0.7,
1.0, 2.0, and >3 μm), is derived by counting upstream challenge particles and the constituent of downstream particles while the
vacuum cleaner system is being operated in a stationary test condition.
1.3 The vacuum cleaner system is tested at the nozzle with the normal airflow rate produced by restricting the inlet to the nozzle
adapter with the 1 ⁄4-in. orifice.
1.4 The vacuum cleaner system is tested with a new filter(s) installed, and with no preliminary dust loading. The fractional
efficiencies determined by this test method shall be considered initial system filtration efficiencies. The filters are not changed
between test runs on the same cleaner.
1.5 Neutralized potassium chloride (KCl) is used as the challenge media in this test method.
1.6 One or two particle counters may be used to satisfy the requirements of this test method. If using one counter, flow control
is required to switch between sampling the upstream and downstream air sampling probes.
1.7 To efficiently utilize this test method, automated test equipment and computer automation is recommended.
1.8 Different sampling parameters, flow rates, and so forth, for the specific applications of the equipment and test procedure may
provide equivalent results. It is beyond the scope of this test method to define those various possibilities.
1.9 This test method is limited to the test apparatus, or its equivalent, as described in this document.
1.10 This test method is not intended or designed to provide any measure of the health effects or medical aspects of vacuum
cleaning.
1.11 This test method is not intended or designed to determine the integrity of HEPA filtration assemblies used in vacuum
cleaner systems employed in nuclear and defense facilities.
1.12 The inch-pound system of units is used in this test method, except for the common usage of the micrometer, μm, for the
description of particle size which is a SI unit.
1.13 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.
2. Referenced Documents
2.1 ASTM Standards:
D1193 Specification for Reagent Water
This test method is under the jurisdiction of ASTM Committee F11 on Vacuum Cleaners and is the direct responsibility of Subcommittee F11.23 on Filtration.
Current edition approved April 1, 2010March 1, 2017. Published May 2010March 2017. Originally approved in 1999. Last previous edition approved in 20042010 as
F1977 – 04. 04 (2010). DOI: 10.1520/F1977-04R10.10.1520/F1977-04R17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1977 − 04 (2017)
FIG. 1 Nozzle Adapter
D1356 Terminology Relating to Sampling and Analysis of Atmospheres
D3154 Test Method for Average Velocity in a Duct (Pitot Tube Method)
F50 Practice for Continuous Sizing and Counting of Airborne Particles in Dust-Controlled Areas and Clean Rooms Using
Instruments Capable of Detecting Single Sub-Micrometre and Larger Particles
F395 Terminology Relating to Vacuum Cleaners
F558 Test Method for Measuring Air Performance Characteristics of Vacuum Cleaners
2.2 Other Documents:
IES Recommended Practice CC021.1—TestingCC021.1 Testing HEPA and ULPA Filter Media
IES Recommended Practice CC001.3—HEPACC001.3 HEPA and ULPA Filters
ISO Guide 25—General25 General Requirements for the Competence of Calibration and Testing Laboratories
EN 1822 High Efficiency Air Filters (HEPA and ULPA)
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 challenge, n—aerosolized media introduced upstream of the test unit and used to determine the filtration characteristics
of the test unit.
Available from Institute of Environmental Sciences and Technology (IEST), Arlington Place One, 2340 S. Arlington Heights Rd., Suite 100, Arlington Heights, IL
60005-4516, http://www.iest.org.
Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http://www.iso.ch.
3.1.1.1 Discussion—
Also known as test aerosol. The term “contaminant” shall not be used to describe the media or aerosol used to challenge the
filtration system in this test method. The term “contaminant” is defined in Terminology D1356 and does not meet the needs of this
test method.
3.1.2 chamber airflow, n—the sum of all airflows measured at a point near the downstream probe.
3.1.3 filter, n—the entity consisting of the converted filter media and other items required to be employed in a vacuum cleaner
for the purpose of arresting and collecting particulate matter from the dirt-laden air stream; sometimes referred to as a filter
element, filter assembly, cartridge, or bag.
3.1.4 normal airflow, n—that airflow occurring at the system’s nozzle due to the 1 ⁄4-in. orifice restriction at the inlet to the
nozzle adapter.
3.1.5 nozzle adaptor, n—a plenum chamber, fabricated to mount to the inlet nozzle of the test unit in a sealable manner and
shown in Fig. 1.
3.1.5.1 Discussion—
Construction specifications are discussed in the Apparatus section.
3.1.6 particle count, n—the numeric sum of particles per cubic foot over the specified sample time.
3.1.6.1 Discussion—
Throughout this test method, the units of measure for this term, generally, do not accompany the term “particle count” and are
assumed to be understood by the reader.
3.1.7 primary motor(s), n—the motor(s) which drive(s) the blower(s), producing airflow through the vacuum cleaner.
3.1.8 secondary motor(s), n—the motor(s) in the vacuum cleaner system not employed for the generation of airflow.
F1977 − 04 (2017)
3.1.9 sheath air, n—the air flowing over and around the test unit that is mounted in the test chamber.
3.1.10 stabilization, n—those conditions of operation which produce results having a total variation of less than 3 % and at least
1000 total count in all size ranges for challenge equal to or less than 15 counts per cubic foot in the 0.3-μm channel for the
background count.
3.1.10.1 Discussion—
Total variation is calculated as the maximum data point minus the minimum data point divided by the maximum data point times
100.
3.1.10.2 Discussion—
The assurance of statistical control is not a simple matter and needs to be addressed. A process is in a state of statistical control
if the variations between the observed test results vary in a predictable manner and show no unassignable trends, cyclical
characteristics, abrupt changes, excess scatter, or other unpredictable variations.
3.1.11 system filtration effıciency, n—a numerical value based on the ratio of a discrete size, particle count emerging from the
vacuum cleaner, relative to the upstream challenge, particle count of the same size.
3.1.12 test chamber, n—the enclosed space surrounding the vacuum cleaner being tested, used to maintain the controlled
environmental conditions required during the test procedure.
3.1.13 test run, n—the definitive procedure that produces a singular measured result.
3.1.13.1 Discussion—
A test run is the period of time during which one complete set of upstream or downstream air sample data, or both, is acquired.
3.2 Definitions:
3.2.1 aerosol, n—a suspension of solid or liquid particles in a gas.
3.2.2 background particles, n—extraneous particles in the air stream prior to the start of the test.
3.2.2.1 Discussion—
Under conditions required of this test method, extraneous particles will be found to pass through the test chamber (for example,
particles penetrating the test chamber’s HEPA filters or being abraded or released from the surfaces of tubing and test equipment).
Operating under stabilized conditions, these particles shall be counted in the downstream flow and subsequently subtracted from
the test data to determine the initial, fractional, filtration efficiency of the test unit (see Note 3).
3.2.3 channel, n—in particle analyzers, a group of particle sizes having a definitive range; the lower end of the range identifies
the channel, for example, a range of particle sizes from 0.3 to 0.5 μm is identified as the 0.3-μm channel.
3.2.4 coincidence error, n—in particle analyzers, errors occurring at concentration levels near or above the design limits of the
instrument being used because two or more particles are simultaneously being sensed.
3.2.5 diffusion dryer, n—in aerosol technology, a device containing desiccant, surrounding the aerosol flow path, that removes
excess moisture by diffusion capture.
3.2.6 diluter, n—in aerosol technology, a device used to reduce the concentration of particles in an aerosol.
3.2.7 downstream, adv—signifies the position of any object or condition that is physically in or part of the airflow stream
occurring after the referenced item.
3.2.8 DPC, n—an acronym for discrete particle counter.
3.2.8.1 Discussion—
The IES Recommended Practice CC001.3 and Practice F50 describe a discrete particle counter as a instrument that utilizes
light-scattering or other suitable principle to count and size discrete particles in air, and that displays or records the results. The
discrete particle counter is also known as a single-particle counter or simply as a particle counter and it determines geometric rather
than aerodynamic particle size.
3.2.9 fractional effıciency, n—a numerical value based on the ratio of the number of emergent, downstream particles of a discrete
size, relative to the number of incident, upstream particles of the same size.
F1977 − 04 (2017)
3.2.9.1 Discussion—
In practice, a single particle size is reported, having an understood or assumed size range equal to the channel size. This value is
also known as the differential size efficiency or particle size efficiency, or both.
3.2.10 fractional effıciency curve, n—the fractional efficiency plotted as a function of the particle size.
3.2.11 HEPA, adj—an acronym for high-efficiency particulate air.
3.2.11.1 Discussion—
Additional information pertaining to HEPA may be found in IES 21.1 (99.97 % at 0.3 μ in salt as modified) or EN 1822 (H12 or
better at 0.3 μ rather than most penetrating particle size).
3.2.12 laminar, adj—in pneumatics, nonturbulent, laminar flow through a pipe is considered laminar when the Reynolds number
is less than approximately 2000 and turbulent for a Reynolds number greater than approximately 4000.
“High Efficiency Particulate Air Filters (HEPA and ULPA),” European Committee for Standardization (CEN), prEN 1822-1:1995, January 1995.
3.2.12.1 Discussion—
Laminar flow in a pipe is characterized by a smooth symmetrical pattern of streamlines. The Reynolds number is a nondimensional
6,7
unit of measure proportional to the ratio of the inertial force of the gas to the frictional forces acting on each element of the fluid.
3.2.13 neutralizer, n—in aerosol technology, a device used to minimize losses and coagulation caused by electrostatic charges,
and to counteract high charge levels in aerosols generated by nebulization, combustion, or dispersion by neutralizing the particle
charge level to the Boltzmann distribution level.
Hinds, William C., Aerosol Technology—Properties, Behavior, and Measurement of Airborne Particles, John Wiley & Sons, 1982, ISBN 0-471-08726-2.
Willeke, Klaus, and Baron, Paul A., Aerosol Measurement—Principles, Techniques, and Applications, John Wiley & Sons, formerly Van Nostrand Reinhold, 1993, ISBN
0-442-004486-9.
3.2.13.1 Discussion—
Neutralizers generally use radioactive Krypton gas, Kr-85, sealed in a stainless steel tube shielded by an outer metal housing.
3.2.14 particle, n—a small, discrete object.
3.2.15 particulate, adj—indicates that the material in question has particle-like properties.
3.2.16 population, n—the total of all the units of a particular model vacuum cleaner being tested.
3.2.17 sample, n—a small, representative group of vacuum cleaners, taken from a large collection (population) of vacuum
cleaners of one particular model, which serve to provide information that may be used as a basis for making a determination
concerning the larger collection.
–6
3.2.18 submicrometer, adj—describes the range of particles having a mean diameter of less than 1 μm (1 × 10 m).
3.2.19 unit or test unit, n—a single vacuum cleaner system of the model being tested.
3.2.20 upstream, adv—signifies the position of any object or condition that is physically in or part of the airflow stream
occurring before the referenced item.
3.2.21 vacuum cleaner, n—as defined in Terminology F395.
3.3 Symbols:
cfm = cubic feet/minute.
D = diameter, in.
ft = feet.
°F = degrees Fahrenheit.
Hz = frequency, Hertz.
H O = water, column.
in. = inch.
psi = pound-force per square inch.
Q = airflow rate, cubic feet/minute.
RH = relative humidity.
F1977 −
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