GB/T 25915.1-2021 Cleanrooms and associated controlled environments—Part 1: Classification of air cleanliness by particle concentration (English Version)
Cleanrooms and associated controlled environments - Part 1: Classification of air cleanliness by particle concentration
1 Scope
This document specifies the classification of air cleanliness in terms of concentration of airborne particles in cleanrooms and clean zones; and separative devices as defined in GB/T 25915.7.
Only particle populations having cumulative distributions based on threshold (lower limit) particle sizes ranging from 0.1 µm to 5 µm are considered for classification purposes.
Concentrations of ultrafine particles (particles smaller than 0.1 µm) will be addressed in a separate standard to specify air cleanliness by nano-scale particles. The use of light scattering (discrete) airborne particle counters (LSAPC) is the basis for determination of the concentration of macroparticles (particles larger than 5 µm) at designated sampling locations. An M descriptor may be used to quantify populations of the macroparticles.
This document cannot be used to characterize the physical, chemical, radiological, viable or other nature of airborne particles.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 25915.2-2021 Cleanrooms and associated controlled environments - Part 2: Monitoring to provide evidence of cleanroom performance related to air cleanliness by particle concentration (ISO 14644-2:2015, IDT)
GB/T 25915.7 Cleanrooms and associated controlled environments - Part 7: Separative devices (clean air hoods, gloveboxes, isolators and minienvironments) (GB/T 25915.7-2020, ISO 14644-7:2004, IDT)
GB/T 29024.4-2017 Determination of particle size distribution - Single particle light interaction methods - Part 4: Light scattering airborne particle counter for clean spaces (ISO 21501-4:2007, IDT)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 General
3.1.1
cleanroom
room within which the number concentration of airborne particles is controlled and classified, and which is designed, constructed and operated in a manner to control the introduction, generation and retention of particles inside the room
Note 1: The class of airborne particle concentration is specified.
Note 2: Levels of other cleanliness attributes such as chemical, viable or nanoscale concentrations in the air, and also surface cleanliness in terms of particle, nanoscale, chemical and viable concentrations might also be specified and controlled.
Note 3: Other relevant physical parameters might also be controlled as required, e.g. temperature, humidity, pressure, vibration and electrostatic.
3.1.2
clean zone
defined space within which the number concentration of airborne particles is controlled and classified, and which is constructed and operated in a manner to control the introduction, generation and retention of contaminants inside the space
Note 1: The class of airborne particle concentration is specified.
Note 2: Levels of other cleanliness attributes such as chemical, viable or nanoscale concentrations in the air, and also surface cleanliness in terms of particle, nanoscale, chemical and viable concentrations might also be specified and controlled.
Note 3: A clean zone(s) can be a defined space within a cleanroom or might be achieved by a separative device. Such a device can be located inside or outside a cleanroom.
Note 4: Other relevant physical parameters might also be controlled as required, e.g. temperature, humidity, pressure, vibration and electrostatic.
3.1.3
installation
cleanroom or one or more clean zones, together with all associated structures, air-treatment systems, services and utilities
3.1.4
classification
method of assessing level of cleanliness against a specification for a cleanroom or clean zone
Note: Levels shall be expressed in terms of an ISO Class, which represents maximum allowable concentrations of particles in a unit volume of air.
3.2 Airborne particles
3.2.1
particle
minute piece of matter with defined physical boundaries
3.2.2
particle size
diameter of a sphere that produces a response, by a given particle-sizing instrument that is equivalent to the response produced by the particle being measured
Note: For discrete-particle light-scattering instruments, the equivalent optical diameter is used.
3.2.3
particle concentration
number of individual particles per unit volume of air
3.2.4
particle size distribution
cumulative distribution of particle concentration as a function of particle size
3.2.5
macroparticle
particle with an equivalent diameter greater than 5 µm
3.2.6
M descriptor
designation for measured or specified concentration of macroparticles per cubic metre of air, expressed in terms of the equivalent diameter that is characteristic of the measurement method used
Note: The M descriptor can be regarded as an upper limit for the averages at sampling locations. M descriptors cannot be used to define ISO Classes, but the M descriptor may be quoted independently or in conjunction with ISO Classes.
3.2.7
unidirectional airflow
controlled airflow through the entire cross-section of a cleanroom or a clean zone with a steady velocity and airstreams that are considered to be parallel
3.2.8
non-unidirectional airflow
air distribution where the supply air entering the cleanroom or clean zone mixes with the internal air by means of induction
3.3 Occupancy states
3.3.1
as-built
condition where the cleanroom or clean zone is complete with all services connected and functioning but with no equipment, furniture, materials or personnel present
3.3.2
at-rest
condition where the cleanroom or clean zone is complete with equipment installed and operating in a manner agreed upon, but with no personnel present
3.3.3
operational
agreed condition where the cleanroom or clean zone is functioning in the specified manner, with equipment operating and with the specified number of personnel present
3.4 Testing instrumentation
3.4.1
resolution
smallest change in a quantity being measured that causes a perceptible change in the corresponding indication
Note: Resolution can depend on, for example, noise (internal or external) or friction. It may also depend on the value of a quantity being measured.
[Source: ISO/IEC Guide 99:2007, 4.14]
3.4.2
maximum permissible measurement error
extreme value of measurement error, with respect to a known reference quantity value, permitted by specifications or regulations for a given measurement, measuring instrument, or measuring system
Note 1: Usually, the term “maximum permissible errors” or “limits of error” is used where there are two extreme values.
Note 2: The term “tolerance” shall not be used to designate “maximum permissible error”.
[Source: ISO/IEC Guide 99:2007, 4.26]
3.5 Instrument specifications
3.5.1
light scattering (discrete) airborne particle counter; LSAPC
instrument capable of counting and sizing single airborne particles and reporting size data in terms of equivalent optical diameter
Note: The specifications for the LSAPC are given in GB/T 29024.4-2017.
3.5.2
discrete-macroparticle counter
instrument capable of counting and sizing single airborne macroparticles
Note: See Table F.1 for specifications.
3.5.3
time-of-flight particle sizing apparatus
discrete-particle counting and sizing apparatus that defines the aerodynamic diameter of particles by measuring the time for a particle to accommodate to a change in air velocity
Note 1: This is usually done by measuring the particle transit time optically after a fluid stream velocity change.
Note 2: See Table F.2 for specifications.
Forward i
Introduction iv
1 Scope
2 Normative references
3 Terms and definitions
4 Classification
5 Demonstration of compliance
Annex A (Normative) Reference method for classification of air cleanliness by particle concentration
Annex B (Informative) Examples of classification calculations
Annex C (Informative) Counting and sizing of airborne macroparticles
Annex D (Informative) Sequential sampling procedure
Annex E (informative) Specification of intermediate decimal cleanliness classes and particle size thresholds
Annex F (Informative) Test instruments
Bibliography
GB/T 25915.1-2021 Cleanrooms and associated controlled environments—Part 1: Classification of air cleanliness by particle concentration (English Version)
Standard No.
GB/T 25915.1-2021
Status
valid
Language
English
File Format
PDF
Word Count
18500 words
Price(USD)
555.0
Implemented on
2022-3-1
Delivery
via email in 1 business day
Detail of GB/T 25915.1-2021
Standard No.
GB/T 25915.1-2021
English Name
Cleanrooms and associated controlled environments—Part 1: Classification of air cleanliness by particle concentration
Cleanrooms and associated controlled environments - Part 1: Classification of air cleanliness by particle concentration
1 Scope
This document specifies the classification of air cleanliness in terms of concentration of airborne particles in cleanrooms and clean zones; and separative devices as defined in GB/T 25915.7.
Only particle populations having cumulative distributions based on threshold (lower limit) particle sizes ranging from 0.1 µm to 5 µm are considered for classification purposes.
Concentrations of ultrafine particles (particles smaller than 0.1 µm) will be addressed in a separate standard to specify air cleanliness by nano-scale particles. The use of light scattering (discrete) airborne particle counters (LSAPC) is the basis for determination of the concentration of macroparticles (particles larger than 5 µm) at designated sampling locations. An M descriptor may be used to quantify populations of the macroparticles.
This document cannot be used to characterize the physical, chemical, radiological, viable or other nature of airborne particles.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 25915.2-2021 Cleanrooms and associated controlled environments - Part 2: Monitoring to provide evidence of cleanroom performance related to air cleanliness by particle concentration (ISO 14644-2:2015, IDT)
GB/T 25915.7 Cleanrooms and associated controlled environments - Part 7: Separative devices (clean air hoods, gloveboxes, isolators and minienvironments) (GB/T 25915.7-2020, ISO 14644-7:2004, IDT)
GB/T 29024.4-2017 Determination of particle size distribution - Single particle light interaction methods - Part 4: Light scattering airborne particle counter for clean spaces (ISO 21501-4:2007, IDT)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 General
3.1.1
cleanroom
room within which the number concentration of airborne particles is controlled and classified, and which is designed, constructed and operated in a manner to control the introduction, generation and retention of particles inside the room
Note 1: The class of airborne particle concentration is specified.
Note 2: Levels of other cleanliness attributes such as chemical, viable or nanoscale concentrations in the air, and also surface cleanliness in terms of particle, nanoscale, chemical and viable concentrations might also be specified and controlled.
Note 3: Other relevant physical parameters might also be controlled as required, e.g. temperature, humidity, pressure, vibration and electrostatic.
3.1.2
clean zone
defined space within which the number concentration of airborne particles is controlled and classified, and which is constructed and operated in a manner to control the introduction, generation and retention of contaminants inside the space
Note 1: The class of airborne particle concentration is specified.
Note 2: Levels of other cleanliness attributes such as chemical, viable or nanoscale concentrations in the air, and also surface cleanliness in terms of particle, nanoscale, chemical and viable concentrations might also be specified and controlled.
Note 3: A clean zone(s) can be a defined space within a cleanroom or might be achieved by a separative device. Such a device can be located inside or outside a cleanroom.
Note 4: Other relevant physical parameters might also be controlled as required, e.g. temperature, humidity, pressure, vibration and electrostatic.
3.1.3
installation
cleanroom or one or more clean zones, together with all associated structures, air-treatment systems, services and utilities
3.1.4
classification
method of assessing level of cleanliness against a specification for a cleanroom or clean zone
Note: Levels shall be expressed in terms of an ISO Class, which represents maximum allowable concentrations of particles in a unit volume of air.
3.2 Airborne particles
3.2.1
particle
minute piece of matter with defined physical boundaries
3.2.2
particle size
diameter of a sphere that produces a response, by a given particle-sizing instrument that is equivalent to the response produced by the particle being measured
Note: For discrete-particle light-scattering instruments, the equivalent optical diameter is used.
3.2.3
particle concentration
number of individual particles per unit volume of air
3.2.4
particle size distribution
cumulative distribution of particle concentration as a function of particle size
3.2.5
macroparticle
particle with an equivalent diameter greater than 5 µm
3.2.6
M descriptor
designation for measured or specified concentration of macroparticles per cubic metre of air, expressed in terms of the equivalent diameter that is characteristic of the measurement method used
Note: The M descriptor can be regarded as an upper limit for the averages at sampling locations. M descriptors cannot be used to define ISO Classes, but the M descriptor may be quoted independently or in conjunction with ISO Classes.
3.2.7
unidirectional airflow
controlled airflow through the entire cross-section of a cleanroom or a clean zone with a steady velocity and airstreams that are considered to be parallel
3.2.8
non-unidirectional airflow
air distribution where the supply air entering the cleanroom or clean zone mixes with the internal air by means of induction
3.3 Occupancy states
3.3.1
as-built
condition where the cleanroom or clean zone is complete with all services connected and functioning but with no equipment, furniture, materials or personnel present
3.3.2
at-rest
condition where the cleanroom or clean zone is complete with equipment installed and operating in a manner agreed upon, but with no personnel present
3.3.3
operational
agreed condition where the cleanroom or clean zone is functioning in the specified manner, with equipment operating and with the specified number of personnel present
3.4 Testing instrumentation
3.4.1
resolution
smallest change in a quantity being measured that causes a perceptible change in the corresponding indication
Note: Resolution can depend on, for example, noise (internal or external) or friction. It may also depend on the value of a quantity being measured.
[Source: ISO/IEC Guide 99:2007, 4.14]
3.4.2
maximum permissible measurement error
extreme value of measurement error, with respect to a known reference quantity value, permitted by specifications or regulations for a given measurement, measuring instrument, or measuring system
Note 1: Usually, the term “maximum permissible errors” or “limits of error” is used where there are two extreme values.
Note 2: The term “tolerance” shall not be used to designate “maximum permissible error”.
[Source: ISO/IEC Guide 99:2007, 4.26]
3.5 Instrument specifications
3.5.1
light scattering (discrete) airborne particle counter; LSAPC
instrument capable of counting and sizing single airborne particles and reporting size data in terms of equivalent optical diameter
Note: The specifications for the LSAPC are given in GB/T 29024.4-2017.
3.5.2
discrete-macroparticle counter
instrument capable of counting and sizing single airborne macroparticles
Note: See Table F.1 for specifications.
3.5.3
time-of-flight particle sizing apparatus
discrete-particle counting and sizing apparatus that defines the aerodynamic diameter of particles by measuring the time for a particle to accommodate to a change in air velocity
Note 1: This is usually done by measuring the particle transit time optically after a fluid stream velocity change.
Note 2: See Table F.2 for specifications.
Contents of GB/T 25915.1-2021
Forward i
Introduction iv
1 Scope
2 Normative references
3 Terms and definitions
4 Classification
5 Demonstration of compliance
Annex A (Normative) Reference method for classification of air cleanliness by particle concentration
Annex B (Informative) Examples of classification calculations
Annex C (Informative) Counting and sizing of airborne macroparticles
Annex D (Informative) Sequential sampling procedure
Annex E (informative) Specification of intermediate decimal cleanliness classes and particle size thresholds
Annex F (Informative) Test instruments
Bibliography