This is a strong filter paper with a medium flow rate and retention. Ahlstrom 613 is commonly used in student laboratories. This strong general-purpose filter is also useful in Buchner funnels for barium carbonate, lead chromate and beryllium hydroxides.

Standard qualitative filter papers are suitable for quadrant folded or gravity flow applications. These grades contain a high level of alpha-cellulose that provides high purity but will weaken when wet. The inherent strength of standard (untreated) grades does not pose a problem when they are used in routine quadrant folded applications. We do not recommend these grades for use in vacuum work or when wet handling is required.