This Recommended Practice (RP) describes methods for testing wipers used in cleanrooms and other controlled environments for characteristics related to both cleanliness and function.

BACKGROUND AND PURPOSE

Tests for wiping materials can be divided into two broad categories, one concerned with function, the other with contamination.

The most important functional characteristic of wipers may be their ability to sorb liquids. Two separate characteristics related to sorbency are relevant: capacity (how much liquid a wiper can sorb) and rate (how fast the wiper can sorb the liquid). Tests for these distinct characteristics are described in section 8.

Tests for contamination (or cleanliness) can be listed almost without end. However, the consensus in hightechnology industries is that particles, non-speciated extractable matter, and individual ionic constituents are the most important contaminants.

Section 5 describes recommended laboratory practices that should be followed when testing wiping products. These practices are designed to promote the quality and validity of all laboratory measurements using standard practices and procedures.

Section 6 describes tests for enumeration of particles releasable from a wiper. The number of particles that can be released from a wiper is maximized when the wiper is immersed in a liquid that will properly wet the fiber surfaces. Thus, testing wipers in a wetted condition is the most efficient way to enumerate these particles. Two methods of sample preparation and two methods of enumeration are described.

Section 7 describes tests for the quantitative analysis of unspecified matter extractable from wipers. Two procedures for extracting and quantifying general extractable matter are described in section 7.1, one a short-term test, the other an exhaustive extraction. Section 7.2 provides guidelines for use when the quantitative analysis of specific constituents is required. Non-speciated extractable matter is covered in section 7.1, while organic compounds and inorganic constituents are described in sections 7.2.1 and 7.2.2, respectively.

Section 8 describes tests for sorbency capacity and sorbency rate.

Section 9 describes test methods for sampling and quantifying bioburden on wiping products. Sterile apparatus and aseptic techniques are required to perform tests.

This RP does not categorize wipers according to their suitability for particular applications. Rather, it offers rational and germane tests to determine those characteristics of wiping materials generally acknowledged to be important. The results of these tests permit the quantitative assessment of the merits of wiping materials according to the mix of properties considered important in relation to their intended use.