Post返source先
http://www.3m.co.uk/intl/uk/ohes/segments/healthcare/(9666a)OH_ReusableTechBulletin_lft.pdf[/url]
P.2
Q - For how long will a set of particular filters last in use?
A - Filters should be
changed when they become clogged with particulate contaminant. The wearer can determine when this occurs as it becomes harder to breathe through the filters.
The filters are designed to filter out particles in industrial conditions and in concentrations much higher than is likely to be encountered in a pandemic situation. It is therefore expected that
one set of filters will cover at least one pandemic wave, after which they should be replaced for infection control reasons.