HEPA AIR FILTERS
ISSUE:
High Efficiency Particulate Air (HEPA) filters.
BACKGROUND:
VA Master Construction Specification Section 15885 `Air Filters' was revised to
include state-of-the-art HEPA bag-in/bag-out type filters replacing the conventional
HEPA filters. Bag-in/Bag-out type filters provide better protection to the facility
personnel when replacing filters with dangerous material.
Consequently, VA Standard Detail No. 15840-21 `Self-contained HEPA Filter for
H3 Fume Hood Exhaust' in PG-18-4, Volume 3, Section II was deleted, as this
detail would not have applied to bag-in/bag-out type filters.
RECOMMENDATIONS/CONCLUSION:
1. Specify bag-in/bag-out type HEPA filters with pre-filters on future projects.
2. Follow manufacturer's recommendations for maintaining and replacing HEPA
filters.
3. Review all safety procedures with the facility safety officer.
4. If HEPA filters are used for TB Isolation Rooms, Center for Disease Control
(CDC) in its Guidelines for Preventing the Transmission of Mycobacterium
tuberculosis in Health-Care Facilities, 1994, states:
"Proper installation and testing and meticulous maintenance are critical if HEPA filtration system
is used, especially if the system used re-circulates air to ot her parts of the facility. Improper
design, installation, or maintenance could allow infectious particles to circumvent filtration and
escape into the general ventilation system. HEPA filters should be installed to prevent leakage
between filter segments and between the filter bed and its frame. A regularly scheduled
maintenance program is required to monitor the HEPA filter for possible leakage and for filter
loading. A quantitative leakage and filter performance test (e.g. the dioctal phthalate) DOP
penetration test should be performed at the initial installation and every time the filter is changed
or removed. The test should be repeated every 6 months for filters in general-use areas and in
areas with systems that exhaust air that is likely to be contaminated with M.tuberculosis (e.g. TB
isolation rooms)."
9 April 1998
FM-187C-DA88
Previous Page
