Cleanrooms and associated controlled environments—Part 2: Monitoring to provide evidence of cleanroom performance related to air cleanliness by particle concentration
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
1 Scope
This document specifies basic requirements for a monitoring plan for cleanroom or clean zone performance related to air cleanliness by particle concentration, based upon parameters that measure or affect airborne particle concentration.
This document is applicable to the monitoring of the concentration of particles with particle size of 0.1μm to 5μm.
This document does not address condition monitoring of aspects such as vibration or general maintenance of the engineering systems. Concentrations of ultrafine particles (particles smaller than 0.1µm) will be addressed in a separate standard.
2 Normative references
The following documents contain requirements which, through reference in this text, constitute provisions 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.
GB/T 25915.1-2021 Cleanrooms and associated controlled environments - Part 1: Classification of air cleanliness by particle concentration (ISO 14644-1:2015, MOD)
Note: There is no technical difference between the referenced content from GB/T 25915.1-2021 and that from ISO 14644-1:2015.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 25915.1-2021 and the following apply.
3.1
test
procedure undertaken in accordance with a defined method to determine the performance of an installation or an element thereof
3.2
monitoring
observations made by measurement in accordance with a defined method and plan to provide evidence of the performance of an installation
Note 1: Monitoring may be continuous, sequential or periodic; and if periodic, the frequency shall be specified.
Note 2: This information may be used to detect trends in operational state and to provide process support.
3.3
action level
level of a parameter set by the user which, when exceeded, requires immediate intervention, including investigation of cause, and corrective action
3.4
alert level
level of a parameter set by the user giving early warning of a drift from normal conditions, which, when exceeded, should result in increased attention or corrective action
4 Creating, implementing and maintaining a monitoring plan
4.1 Principle
In order to gain assurance that a cleanroom or clean zone is performing adequately by delivering the required control of air cleanliness by particle concentration, a monitoring plan shall be created, implemented and maintained.
A monitoring plan shall take into account the level of air cleanliness required, critical locations and performance attributes of the cleanroom or clean zone that affect the performance of the installation. The following steps shall be included in the creation, implementation and maintenance of the monitoring plan:
——use appropriate risk assessment tools to understand, evaluate and document the risk of adverse contamination events;
——develop a written monitoring plan;
——review and approve the plan;
——implement the plan by performing the monitoring;
——analyze the data derived from the monitoring activity, undertake trend analysis where appropriate and report the performance of cleanroom and clean zone;
——implement and document actions or corrective actions required;
——undertake periodic review of the monitoring plan.
The concentration of airborne particles measured under a monitoring plan may be higher than the concentration observed during at-rest test. The observed values may fluctuate considerably due to factors such as the number of personnel present, the airflow rate, ventilation effectiveness, the operation of instruments or machinery, and activities in adjacent spaces.
For processes that inherently produce particles as part of the process and where these particles are not a threat to the process or product, it may be appropriate to rely on periodic at-rest classification, or operational classification of simulated operations, rather than monitoring of airborne particles in operation. Other performance and cleanliness attributes may still be required to be monitored.
4.2 Risk assessment
Risk assessment is a systematic process of identification of hazards and the analysis and assessment of risks associated with exposure to those hazards.
A risk assessment shall be undertaken in order to:
——develop a monitoring plan by determining factors that may affect the ability to maintain the agreed air cleanliness (by particle concentration) of the cleanroom or clean zone; and
——determine the monitoring requirements to provide evidence of performance.
For guidance on what to consider when undertaking a risk assessment, see Annex A.
4.3 Monitoring plan
4.3.1 The monitoring plan shall take into account the output from the risk assessment.
When developing the monitoring plan, the factors described in 4.3.2 to 4.3.13 shall be included as a minimum.
4.3.2 Listing and justification of all the parameters to be monitored, including those that may affect the airborne particle concentration.
Foreword i
Introduction iii
1 Scope
2 Normative references
3 Terms and definitions
4 Creating, implementing and maintaining a monitoring plan
5 Periodic classification of air cleanliness by particle concentration
Annex A (Informative) Matters to consider when developing a monitoring plan
Annex B (Informative) Considerations for setting alert and action levels
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