1) The FEC shall employ
the most economical and energy-efficient systems, in accordance with this
subsection (d), to provide a comfortable, clean and controlled environment.
A) The requirements of this subsection (d) do
not relieve the designer from providing system capacities and components as
required to maintain control of air quality, odor, ventilation rates, space
temperatures and space humidity as set forth in this subsection (d).
B) The design of air conditioning, heating
and ventilation systems shall be based on no less than the recommended outdoor
design conditions listed in the ASHRAE Handbook - Fundamentals for 99%
occurrence (winter) and 1% occurrence (summer).
2) Ventilation Systems
A) Air handling systems shall conform to NFPA
90A.
B) Fire dampers, smoke dampers
and smoke control systems shall be constructed, located and installed in
accordance with the requirements of NFPA 90A.
C) Ducts that penetrate construction intended
for x-ray or other ray protection shall preserve the effectiveness of the
protection.
D) Outdoor air intakes
shall be located at least 15 feet from exhaust outlets of ventilation systems,
combustion equipment stacks, medical/surgical vacuum systems, plumbing vents,
or areas that may collect vehicular exhaust or other noxious fumes, unless
other provisions are made to minimize recirculation of exhaust into outdoor air
intakes. Plumbing and vacuum vents that terminate above the level of the top of
the air intake may be located as close as 10 feet. The bottom of outdoor air
intakes serving central systems shall be located as high as practical but at
least 6 feet above ground level, or, if installed above the roof, 3 feet above
the roof level.
E) Exhaust outlets
from areas that may be contaminated by dangerous or noxious dust, fumes, mists,
gases, odors, infectious material or other contaminants harmful to people shall
be above the roof level. The discharge to the atmosphere shall be located as
far as possible but not less than 25 feet from any operable window, door and/or
outdoor intake for a fan that discharges air to an occupied space.
F) The ventilation systems shall be designed
and balanced to provide the ventilation and pressure relationships specified in
this Section.
G) If the ventilation
rates required in this Section do not provide sufficient make-up air for use by
hoods, safety cabinets and exhaust fans, the additional make-up air shall be
provided to maintain required pressure balance.
H) An all outdoor air system may be used
where required by local codes, provided that some form of air-to-air or
air-to-water heat recovery system is included to reclaim the energy otherwise
discharged with the air exhausted to the outside.
I) To provide maximum energy conservation,
air supplied to patient care areas not required as make-up air for 100% exhaust
systems shall be recirculated. Any air within the FEC that is circulated
between patient rooms, or patient rooms and other areas of the FEC, shall pass
through filters having a minimum efficiency reporting value (MERV) 14 rating
(see subsection (d)(3) on filters).
J) To provide maximum energy conservation,
air supplied to housekeeping, administration and other nonsensitive areas not
required as make-up air for 100% exhaust systems shall be recirculated. These
areas require filters having a MERV 8 rating on the inlet side of the air
handling unit.
K) When a central
system serves areas with different filtration requirements, the most stringent
filtration requirement will be provided for the complete system.
L) All outside air supplied to patient care
areas shall pass through 90% filters (see subsection (d)(3) on
filters).
M) Minimum air
circulation requirements indicated in this Section are applicable to occupied
spaces. During unoccupied periods, minimum air circulation may be provided as
required to maintain space design temperature conditions.
N) Where fan coil or terminal room unit
systems are provided in areas to be occupied by patients, through-the-wall
outside air ventilation is not acceptable. A separate central ventilation
system, with final filters having a MERV 14 rating, shall supply the required
outdoor air ventilation.
O) Only
fully ducted systems are acceptable. Interstitial spaces shall not be used as
plenums for supply/return/exhaust.
3) Filters
A) All central ventilation or air
conditioning systems shall be equipped with filters having efficiencies no less
than those specified in the area requirements (see subsection (e)).
B) Where two filter beds are required, filter
bed No. 1 shall be located upstream of the air conditioning equipment and
filter bed No. 2 shall be located downstream of the supply fan and air
conditioning equipment.
C) Where
only one filter bed is required, it shall be located upstream of the air
conditioning equipment.
D) All
filter efficiencies shall be average atmospheric dust spot efficiencies tested
in accordance with ASHRAE Handbook - Fundamentals.
E) Filter frames shall be durable and shall
provide an air-tight fit with the enclosing ductwork. All joints between filter
segments and enclosing ductwork shall be gasketed or sealed to provide a
positive seal against air leakage.
F) A local indicating device shall be
installed across each filter bed serving central air systems to measure the
static pressure drop across the bed.