IEST-RP-CC002.5

Unidirectional-Flow, Clean-Air Devices

This Recommended Practice (RP), IEST-RP-CC002.5, covers definitions, procedures for evaluating performance, and major requirements of unidirectional-flow, clean-air devices. The RP may be used to define a basis of agreement between customer and supplier in the specification, procurement, and certification testing of unidirectional-flow, clean-air devices with self-contained motorblower(s) and powered terminal units with replaceable filter. This document also presents recommendations for recertification of devices owned by the customer, under direction of the customer. This latest update brings real changes to how you test, certify, and document these devices in the field. Updates include:  · Test tiers have been reframed: primary- and secondary-level testing is no longer split into mandatory versus optional, but instead tied to what regulatory standards, manufacturer specs, or customer requirements actually call for. · Airflow velocity testing (6.1.1) has been streamlined, dropping to one reading per sampling location with a revised tolerance criterion. · The induction leak and backstreaming sections (6.1.3–6.1.4) are now two distinct tests with their own acceptance criteria. Backstreaming is qualitative and visual-medium only, while induction leak testing shifts to an aerosol photometer method or a discrete-particle counter method (failure on a continual-increase trend), replacing the old 1×10 ³ ambient concentration threshold. New (optional) Appendix E offers a quantitative backstreaming option. You'll also notice Table D1's applicability codes are simplified from the old A/B/C/D system to A/NA/* — timing and responsibility now live with the test tier instead. · Brand-new Section 6.3 covers site installation assessments, microbial environmental monitoring (referencing USP <1116> and CETA CAG-009), and the relocation of filter differential pressure testing into that new tier. · Also new: a widened vibration frequency range; a raised ULPA filter efficiency minimum; and a new Section 6.1.6 on airflow visualization studies referencing CETA CAG-014. First printing, September 2026 (Supersedes previous versions, including IEST-RP-CC002.4, IEST-RP-CC002.3, IEST-RP-CC002.2, IES-RP-CC-002-86