ISO 29464:2011

INTERNATIONAL ISO
STANDARD 29464
First edition
2011-09-01
Cleaning equipment for air and other
gases — Terminology
Séparateurs aérauliques — Terminologie

Reference number
©
ISO 2011
©  ISO 2011
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ii © ISO 2011 – All rights reserved

Foreword
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ISO 29464 was prepared by Technical Committee ISO/TC 142, Cleaning equipment for air and other gases.
This first edition of ISO 29464 cancels and replaces ISO 3649:1980, which has been technically revised.

INTERNATIONAL STANDARD ISO 29464:2011(E)

Cleaning equipment for air and other gases — Terminology

1 Scope
This International Standard establishes a terminology for the air filtration industry and comprises terms and
definitions together with, in some cases, symbols and units.
This International Standard is applicable to both particulate and gas phase air filters and cleaners used for the
general ventilation of inhabited enclosed spaces. Air inlet filters for static or seaborne rotary machines are
included.
It does not apply to cabin filters for road vehicles or air inlet filters for mobile internal combustion engines, for
which separate arrangements exist. Dust separators for the purpose of air pollution control are also excluded.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 29463-1, High-efficiency filters and filter media for removing particles in air — Part 1: Classification,
performance testing and marking
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 Particulate filters
3.1.1
aerosol
system of solid or liquid particles suspended in gas
NOTE In general, one divides the atmospheric aerosol into three size categories: the ultrafine range x  0,1 µm, the fine
range 0,1 µm  x  1 µm and the coarse range x  1 µm, whereby x is the particle diameter.
3.1.2
monodisperse aerosol
aerosol, the width of whose distribution function, described by the geometric standard deviation g, is less
than 1,15 µm
3.1.3
polydisperse aerosol
aerosol, the width of whose distribution function, described by the geometric standard deviation g, exceeds
1,5 µm
3.1.4
quasi-monodisperse aerosol
aerosol, the width of whose distribution function, described by the geometric standard deviation g, lies
between 1,15 µm and 1,5 µm
3.1.5
test aerosol
aerosol used for determining filter performance and for calibrating particle measurement devices
3.1.6
agglomerate
collection of solid particles adhering to each other
3.1.7
agglomeration
action leading to the formation of agglomerates
3.1.8
agglutination
action of joining, by impact, solid particles coated with a thin adhesive layer or of trapping solid particles by
impact on a surface coated with adhesive
3.1.9
aggregate
relatively stable assembly of dry particles, formed under the influence of physical forces
3.1.10
filter media area
A
fm
area of media contained in the filter
3.1.11
effective filter media area
area of the media contained in the filter (without adhesive spaces or ligament) and passed by air during
operation
3.1.12
exposed filter area
A
exp
area of filter medium in a filter effective for particle capture
3.1.13
nominal filter face area
A
nff
frontal face area of the filter including the header frame which determines the nominal filter face velocity
3.1.14
arrestance
A
measure of the ability of a filter to remove a standard test dust from the air passing through it, under given
operating conditions
NOTE This measure is expressed as a weight percentage.
3.1.15
average arrestance
A
m
ratio of the total amount of loading dust retained by the filter to the total amount of dust fed up to final test
pressure differential
3.1.16
initial arrestance
value of arrestance determined after the first loading cycle in a filter test
NOTE 1 For example, in EN 14799 procedure for the first 30 g of test dust.
2 © ISO 2011 – All rights reserved

NOTE 2 This measure is expressed as a weight percentage.
3.1.17
ash
solid residue of effectively complete combustion
3.1.18
fly ash
ash entrained by combustion gases
3.1.19
dust holding capacity
DHC
C
d
amount of loading dust retained by the filter up to final pressure differential
3.1.20
capture
extraction of particles, liquid particles or gases, close to their sources for purposes of collection or sampling
3.1.21
classification
allocation of filters into groups and classes according to relevant aspects of their filtration performance
3.1.22
cleaning (after clogging)
removal of the deposit of solid or liquid particles which has produced clogging
3.1.23
clogging
deposition, progressive or otherwise, of solid or liquid particles on or within a filter medium, causing the flow to
be obstructed
3.1.24
coalescence
action by which liquid particles in suspension unite to form larger particles
3.1.25
concentration
content
quantity of a solid, liquid or gaseous material expressed as a proportion of another material in which it is
contained in the form of a mixture, a suspension or a solution
3.1.26
correlation ratio of sampling points
downstream particle concentration divided by the upstream particle concentration (measured without filter)
3.1.27
particle counter
device for detecting and counting numbers of discrete airborne particles present in a sample of air
3.1.28
condensation particle counter
CPC
type of optical particle counter (3.1.29) in which very fine airborne particles are enlarged by condensation to
a size which may readily be counted by other particle counting methods
NOTE 1 It can provide data on particle numbers but not the original size distribution.
NOTE 2 The ISO committee dealing with CPC is TC 24/SC 4.
3.1.29
optical particle counter
OPC
particle counter which functions by illuminating airborne particles in a sample flow of air, converting the
scattered light impulses to electrical impulse data capable of analysis to provide data on particle population
and size distribution
NOTE See ISO 21501-4.
3.1.30
border zone error
with an optical limitation of the measuring volume or by means of the Gaussian distribution of the light
intensity in the laser beam, the particles passing the border of the sensing zone are less illuminated than the
ones passing the centre of the sensing zone
NOTE 1 The border zone error is device- and particle-size-dependent and has a direct effect on the size resolution.
NOTE 2 Due to the border zone error, the particle size is underestimated.
NOTE 3 The larger the particle to be measured, the larger the border zone error.
3.1.31
sizing accuracy
(x)
(x) determined by the function:
xx
measured reference
(x)100
x
reference
3.1.32
sizing resolution
R(x)
indicates which particle sizes can be differentiated by a particle measuring instrument
NOTE The sizing accuracy can be evaluated for any particle size as follows:
()xx ()
measured reference
Rx( )100, geometric standard deviation
x
reference
3.1.33
lower size limit
smallest particle diameter with a counting efficiency of 0,5  0,15 (50 %  15 %)
3.1.34
upper size limit
largest particle diameter with a counting efficiency of 0,5  0,15 (50 %  15 %)
3.1.35
sampling flow rate
volumetric flow rate through the instrument
NOTE Any error in the volume flow will affect the reported particle number concentration.
3.1.36
calibration curve
graph depicting the relationship between scattered light intensity and particle size
NOTE For the clear particle size and quantity determination, an unambiguous, monotonically increasing calibration curve
offers advantages. This enables narrower size intervals to be chosen.
4 © ISO 2011 – All rights reserved

3.1.37
calibrate
to compare readings from the instrument to be calibrated with those from a reference device
3.1.38
calibration particle
mono-disperse spherical particle with a known mean particle size, e.g. polystyrene latex (PSL) particle, that is
traceable to an international standard of length, and where the standard uncertainty of the mean particle size
is equal to or less than  2,5 %
NOTE The refractive index of (PSL) calibration particles is close to 1,59 at a wavelength of 589 nm (sodium D line).
[ISO 21501-3:2007, definition 2.1]
3.1.39
reference device
primary device possessing accurately known parameters used as a standard for calibrating secondary devices
3.1.40
coagulation losses
particle losses due to collision and adhesion of particles
NOTE Coagulation affects the measured particle parameters as follows: the particle number concentration decreases,
the particle mass concentration remains the same and the particle size increases.
3.1.41
counting rate
N
number of counting events per unit time
3.1.42
zero count rate
N
z
number of counts registered per unit time by the particle counter when air, which is free of particles, is passed
through the measuring volume
3.1.43
cyclone
dust separator or droplet separator utilizing essentially the centrifugal force derived from the motion of the gas
3.1.44
DEHS
DiEthylHexylSebacate
liquid used for generating the DEHS test aerosol
3.1.45
equivalent diameter
diameter of a spherical particle which will give behaviour equivalent to that of the particle being examined
3.1.46
count median diameter of aerosol
number median diameter of aerosol
CMD
d
m
50th percentile of the number distribution of the aerosol
NOTE 50 % of the particles are smaller than the count median diameter and 50 % are larger than the count median
diameter.
3.1.47
count mean particle diameter
number mean particle diameter
d
pm
geometric average of the lower and upper limit of the size range
3.1.48
dispersion
operation as a result of which solid particles or liquid particles are distributed in a fluid
NOTE Also applied to a two-phase system in which one phase, known as the “disperse phase”, is distributed throughout
the other, known as the “continuous medium”, e.g. DOP (Dioctyl phthalate) liquid, or liquids with similar physical
properties, are dispersed in air to generate a test aerosol.
3.1.49
downstream
area or region into which fluid flows on leaving the filter
3.1.50
droplet
liquid particle of small mass, capable of remaining in suspension in a gas
NOTE In some turbulent systems, for example clouds, its diameter can reach 200 µm.
3.1.51
dust
airborne solid particles which settle by gravity in calm conditions
3.1.52
test dust capacity
TDC
amount of loading dust held by the filter at final test pressure differential
3.1.53
dust control
whole of the processes for the separation of solid particles from a gas stream in which they are suspended
NOTE By extension this also includes the activities involved in the construction and commissioning of a dust separator.
3.1.54
loading dust
synthetic dust formulated specifically for determination of the test dust capacity and arrestance of air filters
NOTE A number of loading dusts are currently used, e.g. ISO fine test dust, ASHRAE dust and JIS-11.
3.1.55
efficiency
E
fraction of contaminant entering the filter which is retained
3.1.56
average efficiency
E
av
value of efficiency which results from averaging the efficiencies determined over a number of discrete intervals
up to the final pressure differential
6 © ISO 2011 – All rights reserved

3.1.57
collection efficiency
ratio of the quantity of particles retained by a separator to the quantity entering it with regard to filters, dust
separators and droplet separators
NOTE It is generally expressed as a percentage.
3.1.58
conditioned efficiency
...