MIL-HDBK-1191
Critical, Sensitive, Clinic, Administrative, Support areas, and Patient
Bedroom areas. The primary considerations of the HVAC design are to
provide the environmental conditions required to meet the functional
requirements. Multizone, dual-duct, terminal reheat, variable air volume,
and combinations of such air distribution systems may be considered for
application in appropriate areas. If utilized, VAV systems will be of the
minimum air quantity type. All-water, unitary, and fan-powered VAV systems
will generally not be acceptable in medical facilities, due to their
limitations in meeting ventilation requirements, increased contamination
source potential, or increased maintenance requirements.
8.7.1
Critical Care Spaces. These spaces will normally be served by
single duct terminal reheat or double duct systems. Simultaneous
temperature, humidity, and pressurization control requirements for these
spaces preclude the use of other types of systems.
8.7.1.1
Operating & Delivery Room (OR and DR) Air Systems. The room
air supply system for Operating Rooms, Delivery Rooms, Cardiac
Catheterization (hospital) Rooms, and Cystoscopy (hospital) Rooms shall be
a ceiling supply type, located over the operating table or treatment area,
using non-aspirating "low velocity" (0.2 - 0.41 m/s)(40-90 fpm) diffusers
that isolate the air over the operating or treatment area. Room
exhaust/return provisions shall consist of a minimum of two exhaust or
return registers, located at diagonally opposing corners of the room,
mounted with bottoms of registers between 150 mm (6 in) and 230 mm (9 in)
above finished floor. The HVAC system for anesthetizing locations,
including operating and delivery rooms, shall be designed in accordance
with NFPA 99 to (a) prevent recirculation of smoke originating within the
surgical suite and (b) prevent the circulation of smoke entering the system
intake, without in either case interfering with the exhaust function of the
system.
8.7.1.2
Continuity of Service. The design for the HVAC systems serving
Critical Care spaces shall include the following:
a) The Air Handling Unit(s (AHUs) serving Operating or
Delivery Room suites shall be separate, independent units serving only the
respective Surgical or Obstetrical Department or portions thereof, to
enhance the reliability of these systems and minimize demand on the
emergency power system. The air handling unit(s) serving each suite may
also provide service to other Patient Care or support areas outside the
respective Surgical or Obstetrical Department. A maximum of four ORs or
four DRs should be served by any single AHU. Where a facility has four or
fewer ORs, these should be served by at least two separate air handling
systems, to enhance reliability; A similar consideration should apply for
DRs.
b) HVAC equipment, including controls, which serve Critical
Spaces (including ventilation and pressure controls for isolation bedrooms)
shall be connected to the emergency electrical power system. This shall
include a sufficient number of chillers and boilers, with necessary
supporting equipment, to meet critical design loads.
8-5
Previous Page
