Unless otherwise indicated, all general requirements apply to both new construction and an existing nursing home. An existing nursing home shall provide for adequate ventilation through windows or mechanical means or a combination of both. A new nursing home shall adhere to the requirements of this chapter. Ventilation System Details. All air-supply and air-exhaust systems shall be mechanically operated. The ventilation rates shown in Table 1 under §D(10) of this regulation shall be considered the minimum acceptable rates and may not be construed as precluding the use of higher ventilation rates. All fans serving exhaust systems shall be located at the discharge end of the system. Outdoor air intakes shall be located: As far as practical but not less than 25 feet from: Exhaust outlets of ventilating systems; Combustion equipment stacks; Medical-surgical vacuum systems; Plumbing vent stacks; or Areas that may collect vehicular exhaust and other noxious fumes; and As high as practical, so that the bottom of the outdoor air intake is: At least 6 feet above ground level; or At least 3 feet above roof level. The ventilation systems shall be designed and balanced to provide the pressure relationships as shown in Table 1 under §D(10) of this regulation. The bottoms of ventilation openings may not be not less than 3 inches above the floor of any room. Corridors may not be used to supply air to or exhaust air from any room, except that air from corridors may be used to ventilate bathrooms, toilet rooms, janitors’ closets, and small electrical or telephone closets opening directly on corridors. Filters. A central ventilation or air conditioning system shall be equipped with filters having efficiencies no less than those specified in Table 2 under §D(11) of this regulation. The filter bed shall be located upstream of the air conditioning equipment, unless a prefilter is employed. If a prefilter is employed, the prefilter shall be upstream of the equipment and the main filter bed may be located further downstream. A filter or filter efficiency shall comply with the standards of the Guidelines for Design and Construction of Residential Health, Care, and Support Facilities. A filter frame shall be durable and carefully dimensioned and shall have an airtight fit with the enclosing duct work. A joint between filter segments and the enclosing duct work shall be gasketed or sealed to provide a positive seal against air leakage. A manometer shall be installed across each filter bed serving central air systems. Air Ducts. Air-handling duct systems shall meet the requirements applicable to nursing homes cited in NFPA 99 Health Care Facilities Code. Fire and smoke dampers shall be constructed, located, and installed in accordance with the requirements of NFPA 101 Life Safety Code. Air ducts that pass through a required smoke barrier shall be provided with a smoke damper at the barrier. Smoke dampers shall activate by smoke detectors located in the ducts at the smoke barrier, or by the smoke detectors used to close smoke barrier doors. Smoke dampers shall be controlled to close automatically to prevent flow of smoke-laden air in either direction. Smoke dampers shall be equipped with automatic remote control reset devices, except that manual reopening will be permitted if smoke dampers are accessible. All devices shall be interlocked with the fire alarm system. Table 1. This table refers to the pressure relationships and ventilation of certain areas of a nursing home other than chronic disease hospitals. Table 2. This table refers to the filter efficiencies for central ventilation and air conditioning systems in a nursing home other than chronic disease hospitals. Exhaust Hoods. All hoods over cooking surfaces shall comply with the requirements as provided in COMAR 10.15.03.