1. Summary
The VALAIRDATA integrity test uses an aerosol challenge method based on generation of a defined aerosol from Shell Ondina EL oil. Whilst this oil meets the UK Mineral Hydrocarbons in Food Regulations 1966 (SI No 1073) and FDA Federal Code Regulation 178-3620(a) for food quality white oils, users have expressed interest in levels of oil carry over to the downstream sector of filtration systems during testing. This study was performed to determine the level of any potential challenge fluid (Shell Ondina oil) carry over in vapour phase at both ambient and elevated temperature. HIGH FLOW TETPOR air sterilisation filter cartridges were integrity tested, and hydrocarbon carry over downstream determined using flame ionization detection (FID). The following experimental variations were included in the study: - Cartridge integrity tested and steam sterilised to remove residual challenge fluid prior to FID analysis. FID analysis was conducted on two cartridges at 23°C (73.4°F) and 60°C (140°F), respectively. Best case scenario. - Cartridge integrity tested and carry over determined by FID at 23°C (73.4°F). Typical situation. - Cartridges tested 12 times consecutively and carry over determined by FID at 60°C (140°F). Worst case scenario. The data showed that in all cases the level of hydrocarbon detected downstream of the test cartridges was the same regardless of cartridge treatment. In addition, the levels detected were the same as background controls and at the level of the sensitivity of detection for the FID system. These data indicate that the level of carry over of hydrocarbon following VALAIRDATA integrity testing, in the absence of post test steam sterilisation and at elevated operating temperature is negligible.
2. Methods
All tests were performed on 5¨ (125mm) HIGH FLOW TETPOR air sterilisation cartridges (product code ZCHT-AZ) installed in a 5¨ HIGH FLOW air vessel (product code ZVA-01A-BTE). Air was supplied to the test rig from the laboratory ring main and a heater was installed in-line immediately prior to the test vessel. Tests were performed at both ambient temperature and with an inlet air temperature of 60°C (140°F). Immediately after the test vessel a sample port was installed to allow downstream air samples to be analysed by FID. The Flame Ionization Detection Instrument was run for 24 hours to ensure the oven was up to temperature and the instrument fully stable. Meter readings from the instrument were recorded using a flat bed chart recorder and the flow through the rig was measured using a rotameter (Model No. RD068) and set a 600l/min-1 ANR. Before proceeding with the following tests, the Flame Ionisation Detection Instrument was adjusted for zero reading and span using the calibration gases. Air was passed through the test vessel with the heaters on and the temperature regulated to 60°C (140°F). When temperature stabilisation was achieved a background reading of total hydrocarbon vapour was recorded.
N°.1 Serial N°. 47415 - Integrity tested and steam sterilised - FID 60°C (140°F)
N°.2 Serial N°. 48567 - Integrity tested and steam sterilised - FID 23°C (73.4°F)
N°.3 Serial N°. 48570 - Integrity tested - FID 23°C (73.4°F)
N°.4 Serial N°. 48569 - Integrity tested cumulatively 12X - FID 60°C (140°F)
Integrity testing
Integrity testing was performed using a VALAIRDATA Integrity Test system. The standard test time of 10 seconds for a 5¨ (125mm) ZCHT-AZ HIGH FLOW TETPOR air sterilisation filter cartridge was employed.
Steam sterilisation
Where applicable cartridges were steamed in line at 121°C (249.8°F) for 30 minutes followed by flash drying is 10 seconds. Test fluid employed by the VALAIRDATA is Shell Ondina EL, (full materials data safety sheet attached). Steam sterilisation was carried out for 30 minutes followed by flash drying.
FID
The FID temperature relates to the temperature of the air entering the housing inlet. Higher temperature studies were performed as a worst case in terms of generating hydrocarbons in the vapour phase. The specification for the FID analysis is as follows;
Type:
AAL FID Serial No. 520-2303
Gases:
Hydrogen Grade 5.0 Purity 99.999%
Hydrocarbon Content 0.5ppm
Bottle No. BD47889-F
Ultra Zero Air
Hydrocarbon Content 0.2ppm
Methane Standard 9.1ppm certified standard
Bottle No. 8562B Operating Settings:
Zero Suppression - 0.04 @ 0.0 ppm Span Calibrate - 6.70 @ 9.1 ppm
3. Results
Results are shown in Table 1. From these data it can be seen that the levels of hydrocarbons detected downstream of the test cartridges are the same regardless of process conditions (inlet air temperature, plus or minus steam sterilisation, single or multiple integrity tests) and comparable to the levels seen from background analysis. The levels described are very low and at the limit of detection for the FID system.
Table 1: PPM hydrocarbon readings downstream of test cartridges following VALAIRDATA integrity testing under a range of conditions.
4. Technical Support Group activities
domnick hunter have a trained team of scientists and engineers available to answer questions regarding the technical capabilities of our products, to assist in the selection and design of appropriate filtration systems and to provide user training programs. The following services can be delivered both on site and in-house;
- filterability testing to optimise filter system design
- advice on the development of integrity testing, steam sterilisation and clean in place procedures
- development of validation procedures
- troubleshooting
- facility audits to ensure continued optimisation of filter use
- operator training including filtration theory, filter system design and management, validation, etc.
For more information on any of the above support services please contact your local domnick hunter representative. email: tsg@domnickhunter.com
