have efficiency effective for particles down to 5 LIm. Prefilte:
filters shall be installed either on or 1n the intake grid of the unit and held in place
with special housings or clamps.
5. Instrumentation: Each unit shall be equipped with a magnahelic gauge or
manometer to measure the pressure drop across filters and indicate when filters
have become loaded and need to be changed. A table indicating the useable air-
handling capacity for various static pressure readings on the magnahelic gauge
shall be affixed near the gauge for reference or the magnahelic reading indicating
at what point the filters should be changed, noting Cubic Feet per Minute (CFM)
air delivery at the point.
6. Provide units equipped with an elapsed time meter to show the total accumulated
hours of operation.
7. Safety and Warning Devices: The unit shall have an electrical (or mechanical)
lockout to prevent fan from operating without a HEPA filter or with a filter
installed backwards. Units shall be equipped with automatic shutdown system to
stop fan in the event of a major rupture in the HEPA filter or blocked air
discharge. Warning lights and audible alarms are required to indicate normal
operation, excessive pressure drop across the filters (e.g., filter overloading), and
too low of a pressure drop (e.g., major rupture in HEPA filter or obstructed
discharge).
8. Flexible hoses (ducts) of sufficient length shall be provided by the Contractor to
allow the units to discharge outside of buildings.
9. Electrical components shall be approved by the National Electrical Manufacturers
Association (NEMA) and Underwriter's Laboratories (UL). Each unit shall be
equipped with overload protection sized for the equipment. The motor, fan, fan
housing, and cabinet shall be grounded.
B. Respirator Protection Equipment
1. Air Purifying Respirators: Provide, at aminimum, HEPA type filters labeled with
NIOSH and MSHA Certification for "Radionuclides, Radon Daughters, Dust,
Fumes, Mists including Asbestos-Containing Dusts and Mists" and color coded in
accordance with ANSI Z228.2 (1980). In addition, a chemical cartridge section
may be added, if required, for solvents, etc., in use. In this case, provide
cartridges that have each section of the combination canister labeled with the
appropriate color code and NIOSH/MSHA Certification.
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