Your question – our answer
How often should the terminal HEPA filter integrity test be performed? Is there a default? Or do we need to perform a risk analysis and determine the intervals based on this?
A) If the (commercial) operating license was granted according to purely legal requirements, a documented risk assessment is recommended in any case to justify the inspection intervals.
B) If, in addition to the legal requirements, the operating license is also in accordance with EU GMP guidelines, it is sufficient, until the revision of Annex 1, to carry out a documented risk assessment to justify the test intervals (see under "What points should the risk assessment cover? ").
On the part of the authorities, however, a semi-annual inspection is expected for ISO class 5 (laminar flow is equated with GMP Grade A). In the revision of Annex 1 (draft 2020), these intervals are already described (see under "Which GMP regulations and standards apply here?").
A reference to the periodic review could be included in the operating permit. The legal requirements according to which the permit was issued should also be apparent there.
If the facilities and the production operations are approved and conducted in accordance with GMP, the legal requirements still provide the primary governance. Although the GMP guidelines are legally considered a "recommendation", the recommendations of the guidelines are considered a "requirement" by the authorities/inspectors and are also evaluated as such. Since an injection moulding machine is involved, the Medical Devices Directive may also be authoritative, depending on the product manufactured and its use (e.g. as an "accessory to a medical device"). In addition, the EU GMP Guide, whereby "aseptic" production can be excluded, can form the basis of the approval, whereby "non-sterile production" also does not specify Grade A (ISO 5) or B. The GMP guidelines in turn refer to the ISO 14644 series of standards for cleanroom-related topics.
This means: If the approval was granted under the EU GMP Guide, one should use the "requirements“ of the GMP Guide in addition to the ISO 14644 series for the assessment. If this is not the case, i.e. a purely "commercial" operating permit is in place, one can only use the ISO guidelines as a basis for assessment.
All guidelines have one thing in common when setting an inspection interval: the risk should be assessed.
In a risk assessment for the evaluation of a leak in a HEPA filter (class H13 or H14 according to EN 1822), the following points would have to be considered (no claim to completeness):
In the currently valid Annex 1 (2008) of the EU GMP Guideline, the monitoring of clean rooms and clean air systems is described as follows:
8. Clean rooms and clean air devices should be routinely monitored in operation and the monitoring locations based on a formal risk analysis study and the results obtained during the classification of rooms and/or clean air devices.
9. For Grade A zones, particle monitoring should be undertaken for the full duration of critical processing, including equipment assembly, except where justified by contaminants in the process that would damage the particle counter or present a hazard, e.g. live organisms and radiological hazards. In such cases, monitoring during routine equipment setup operations should be undertaken prior to exposure to the risk. Monitoring during simulated operations should also be performed.
The Grade A zone should be monitored at such a frequency and with a suitable sample size that all interventions, transient events and any system deterioration would be captured, and alarms triggered if alert limits are exceeded. It is accepted that it may not always be possible to demonstrate low levels of ≥5.0 µm particles at the point of fill when the filling is in progress, due to the generation of particles or droplets from the product itself.
The draft Annex 1 (2020) - which is not expected to be published until the end of 2021 and will come into force in 2022 - proscribes a periodic review:
Intervals for the test:
For Grade A (ISO 5) & B, the maximum interval for "requalification" is 6 months and for Grade C & D, the maximum interval is 12 months.
EN ISO 14644-2:2016 describes in clause 5:
5. Periodic classification of air cleanliness by particle concentration
Periodic classification testing shall be undertaken annually in accordance with ISO 14644-1. This frequency can be extended based on risk assessment, the extent of the monitoring system, and data that are consistently in compliance with acceptance limits or levels defined in the monitoring plan.
NOTE: ISO 14644-3 specifies ancillary tests related to other aspects of cleanroom performance such as pressure difference, airflow, etc.
EN ISO 14644-3:2020 describes in the annex:
A.3 Scheduling of tests and retests. At a minimum, tests should be conducted as follows:
(a) according to the classification following ISO 14644-1;
(b) during the retest during the initial commissioning;
(c) during the retest after detection and correction of faults;
(d) during the retest after a modification;
(e) during the periodic retest.
Risk assessments should be carried out to determine appropriate intervals for periodic tests. Monitoring data, trends and test results should be used to confirm and, if necessary, adjust the time intervals for the selected tests. (Quote from the EN ISO 14644-3:2020 is an internal translation from the German standard.)
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