What evidence supports use of long-stored stock, and how can expired or damaged stock be identified?

What evidence supports use of long-stored stock, and how can expired or damaged stock be identified?

The conditions the material was tested under are named on the Validation page, and heat and storage are among them.

The conditions listed on the Validation page are heavy dust loaded, fast air flow, used filter for 1 year, after 60 washes, after 2 years of storage, and after 60C for 64 days. Hong Kong Metropolitan University, Test Report IRITS202112110001, 11 December 2021, tested a spunlace nonwoven against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa with reference to BS EN ISO 20743:2013 (transfer method), after accelerated ageing to ASTM F1980-16 for 64 days at 60 °C, and reported: “No significant deterioration of antimicrobial activity was observed after accelerated aging”. It is a contact test on fabric, not an air-filter or airborne result. A condition named in a test is not a shelf life, and the company publishes no expiry date for the filter. The label sets how a new filter is stored: flat or on edge in its original packaging, indoors and dry, away from direct sunlight and moisture, with no loads stacked on the media. It instructs: “Do not install a filter whose media is torn, crushed, wet or visibly damaged.” and “Do not cut, fold, trim, bend, puncture or alter the filter or its frame.” A filter that does not meet those directions when it is taken out of its packaging is not installed.

Source: C-POLAR — Validation, https://cpolar.tech/validation/; NanoFlashing™ Air Filter label, Storage and Disposal and Directions for Use; Hong Kong Metropolitan University, Test Report IRITS202112110001, 11 December 2021. A copy may be made available on our review of the request.

Reviewed on 21 September 2026.