What are the requirements of the Telcordia NEBS standards pertaining to air filters?
• NEBS GR-63-CORE R4-45 [93] Foamed polymers shall meet the HF-1 requirements of ANSI/UL 94-1996. NOTE: Foamed polymer air filter assemblies must also meet the firespread requirements of Section 4.5, “Airborne Contaminants.” R4-87 [138] All fan-cooled equipment shall be equipped with filters. Fan filters shall be replaceable with equipment operating. Fans used to cool the outside of sealed equipment cabinets need not be fitted with particulate filters. R4-88 [139] All equipment fan filters used in equipment occupying over 2U of vertical rack space (90 mm or 3.5 in) shall have either a: Minimum dust arrestance of 80%, per ASHRAE Standard 52.1, Gravimetric and Dust-Spot Procedures for Testing Air Cleaning Devices Used in General Ventilation for Removing Particulate Matter, 1992, or Minimum Efficiency Rating Value (MERV) of 4, per ASHRAE Standard 52.2, Method of Testing General Ventilation Air Cleaning Devices for Removal Efficiency by Particle Size, 1999. R4-89 [176] All equipment fan fi
