scope:

FOREWORD

The first part of this addendum is part of a larger plan to combine Standards 52.1 and 52.2 into a single standard on air filter testing. It incorporates the 52.1 sections on arrestance and dust-holding capacity into Standard 52.2 and deletes some references to Standard 52.1 that occur in Standard 52.2. Future addenda will complete the process of making Standard 52.2 self-sufficient and comprehensive, and at this time SPC 52.1 will be able to withdraw Standard 52.1. While similar to previous definitions, the terms arrestance and dust holding capacity are procedurally different and should not be directly compared to prior definitions in previous versions of Standard 52.

Part 2 of this addendum adds a new informative appendix to Standard 52.2, Appendix J. Appendix J provides an optional method of conditioning a filter using fine KCl particles to demonstrate efficiency loss that might be realized in field applications. When Standard 52.2-1999 was published, the project committee recognized that the conditioning step, also called the first dust-loading step, was not fully adequate for revealing the drop in efficiency that some filters undergo during actual use. This is pointed out in the standard's foreword: "The initial conditioning step of the dust-loading procedure described in this standard may affect the efficiency of the filter but not as much as would be observed in actual service." This is further discussed in Appendix A of the standard (A2.2 and A2.3) where it is stated that "ASHRAE Technical Committee 2.4 has funded a research project to develop a loading dust for a new loading test method that will more nearly represent the minimum efficiency points in actual real-world use." This procedure is an outcome of that research project (ASHRAE RP-1190, "Develop a New Loading Dust and Dust Loading Procedures for the ASHRAE Filter Test Standards 52.1 and 52.2") and ASHRAE RP-1189, "Investigation of Mechanisms and Operating Environments that Impact the Filtration Efficiency of Charged Air Filtration Media," and subsequent committee action.

The procedure described in Informative Appendix J is the result of project committee revisions in response to comments received during two public reviews of the procedure. Since these revisions, however, the procedure has not been issued for another public review, and Appendix J is not ANSI approved.