7.7 Surgical Unit

The number of operating rooms and recovery beds and the size of support areas should be based on the anticipated surgical workload. In planning, the size, location, and layout of the surgical unit and the corresponding support departments should reflect the number of outpatients. This may be designed as an outpatient surgery unit or as a surgical unit shared by inpatients and outpatients. The surgical unit should be located in a position that avoids traffic corridors.

When bronchoscopic or esophagoscopic examinations are performed on patients with confirmed or suspected pulmonary tuberculosis, the ventilation rate of the examination room should be determined in accordance with the requirements for an airborne infection isolation room.

Invasive procedures on patients with confirmed or suspected carriage of airborne infectious pathogens should not be performed in operating rooms, but rather in rooms that meet the ventilation requirements of an airborne infection isolation room or that employ local exhaust; if surgery must be performed in an operating room, refer to the CDC's Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Facilities.

In addition, the following facilities should be provided for the dedicated operating rooms of larger hospitals:

7.7.A Surgery

7.7.A1 General operating rooms. In new construction, each room should have a clear floor area of at least 400 ft² (37.16 m²), exclusive of fixed or wall-mounted cabinets and shelves, with a minimum clearance of 20 ft (6.10 m) between fixed cabinets and shelves, and a communication system should be established between the emergency department and the surgical unit control room. The X-ray machine should be capable of taking at least 4 films simultaneously. In renovation work, every effort should be made to meet the above minimum standards. If it is impossible to meet the above area standards, the authority having jurisdiction may approve a slight deviation from the standard. In that case, each room should have a clear floor area of at least 380 ft² (33.45 m²), exclusive of fixed or wall-mounted cabinets and shelves, with a minimum clearance of 18 ft (5.49 m) between fixed cabinets and shelves (for renovation work, see Section 7.7.A6).

7.7.A2 Rooms for cardiovascular, orthopedic, neurological, and other specialty procedures require more personnel and large equipment; these rooms should have a clear floor area of at least 600 ft² (55.74 m²), exclusive of fixed or wall-mounted cabinets and shelves, and a clearance of 20 ft (6.10 m). When cardiac surgery is performed, it is preferable to provide, near the operating room or in an area of the surgical suite where conditions permit, an annex room to serve as a cardiac room for storing the human heart (to ensure supply) and its accessories. When complex orthopedic and neurosurgical operations are performed, it is preferable to provide, near the operating room or in an area of the surgical suite where conditions permit, an annex room to serve as a storage room for the large equipment used during the operations. Appropriate piping and electrical connections should be provided for the cardiovascular, orthopedic, neurosurgery, cardiac, and storage rooms. In renovation work, every effort should be made to meet the above minimum standards. If it is impossible to meet the above area standards, the authority having jurisdiction may approve a slight deviation from the standard requirements. In that case, the minimum net area of an orthopedic operating room may be 360 ft² (33.48 m²), with a minimum clearance of 18 ft (5.49 m), and the minimum net area for cardiovascular, neurological, and other specialties is 400 ft² (37.16 m²).

7.7.A3 Orthopedic room. If an orthopedic room is provided, a storage room for splints and traction equipment should also be provided in addition to the above requirements. The storage room may be located outside the operating room, but it must be in a convenient location; if a wash sink is used for handling plaster casts, there should be provided a plaster cast sto water trap.

7.7.A4　Surgical cystoscopy and other urethral examination rooms. Except for fixed or built-in casework and shelves, these rooms shall have a clear floor area of at least 350 ft² (32.52 m²). A minimum of 15 ft² (4.57 m²) of clearance shall be provided between fixed casework and shelves. The X-ray machine shall be capable of taking at least 4 films simultaneously. In renovation, surgical cystoscopy rooms shall have a clear floor area of at least 250 ft² (23.28 m²).

7.7.A5　For endoscopic examination requirements, see Section 9.9.

7.7.A6　The functional program may require additional clear floor areas, plumbing, and mechanical systems to provide dedicated service to one or more of these rooms. When existing operating rooms are adapted, if walls or other structural conditions make it impossible to increase the floor area and the hospital has a need for them, the operating rooms may continue to be used.

7.7.B1　Preoperative patient holding area. In hospitals with two or more operating rooms, space for the accommodation and rest of patients on stretchers and of ambulatory patients not requiring stretchers shall be provided. These areas shall be under the direct visual observation of nursing staff.

7.7.B2　Post-anesthesia care units (PACUs). Each PACU shall include a medication station, hand-washing sinks, a nurses' station with recording facilities, a clinical sink, bedpan-washing facilities, stretchers, and storage space for supplies and equipment. In addition, a minimum of 80 ft² (7.43 m²) of floor space shall be provided for each bed designed for additional equipment as described in the functional program, and a minimum of 4 ft² (1.22 m²) shall be provided between beds and between beds and adjacent walls. Isolation rooms shall be provided for infectious patients. Provisions for patient privacy, such as curtains, shall be provided. In new construction, at least one door shall be provided for direct access from the surgical suite to the recovery room without passing through the public corridors of the hospital.

Airborne infection isolation rooms are not required in the PACU. Recovery room provisions for patients carrying airborne pathogens shall be determined by the infection control risk assessment.

Toilet rooms for medical staff shall be located in the work area so that staff members are readily available to patients at all times.

At least one automatically controlled hand-washing facility shall be provided for every 4 beds, evenly distributed so that each bed has equal access to it.

7.7.C　Support Areas

If obstetrics is included in the functional program, the support areas may be shared with it, except for the closed soiled workroom mentioned in item 7.7C6 and the clean workroom in item 7.7C19. When shared with the birthing rooms, the design of the support areas shall avoid the passage of patients or staff between the operating rooms and the birthing rooms. The following services shall be provided:

7.7.C1　A control room from which all persons and materials entering the area can be observed.

7.7.C2　A head nurse's office or nurses' station.

7.7.C3　Flash sterilization facilities or other sterilizing equipment for emergency use shall be provided separately and shall be conveniently and efficiently accessible to several operating rooms. A work area and hand-washing facilities shall be provided. Other facilities for the processing and sterilization of reusable instruments may be located in another department of the hospital, such as the central supply department.

7.7.C4　Medication station. Conditions for the storage and dispensing of medications and routine drugs shall be provided. This may be accomplished by means of a medication dispensing unit or department, an automated dispensing room, or other systems. If a medication dispensing room or department is used, it shall be under the visual control of nursing staff. It shall include a work counter, a sink, a refrigerator, and a double-locked storage room for controlled substances, and shall provide conveniently accessible hand-washing facilities (the standard cup sinks in many automated units cannot be used for handwashing).

7.7.C5　Scrub facilities. Two scrub rooms shall be provided near the entrance of each operating room. If both are close to the operating room entrances, the two scrub rooms may serve two operating rooms. Scrub rooms shall be located in positions that minimize interference with nearby personnel, medical equipment, or supply carts. In new construction, the scrub room shall be provided with a vision panel allowing observation of the interior of the operating room. Scrub sinks shall be located in alcoves away from the main traffic areas. The alcoves shall be located outside the semirestricted or restricted areas of the surgical suite. Scrub rooms shall be located where there is no outside the septic zone.

7.7.C6　A closed soiled workroom dedicated to surgical use (or a soiled holding room as part of a system for collecting and handling soiled items) shall be provided. It shall be located in the restricted zone. The soiled workroom shall contain a clinical sink or similar facility, hand-washing facilities, work counters, and a holding area for waste materials and used linens. A room used only for the temporary holding of soiled items may omit the clinical sink and work counters. However, if the rim-flush clinical sink is omitted, other facilities for the disposal of liquid waste shall be provided. This room shall not have a direct connection with operating rooms or other sterile rooms. Soiled rooms shall be separated from clean rooms or storage rooms.

7.7.C7　Clean workroom or supply room

a. A clean workroom for clean supply materials prior to use or disinfection shall be provided. It shall contain a work counter, a hand-washing sink, storage facilities for clean items, and an area for reusable items. The sterile supply storage room shall be separate from this area. Where the room is used only for storage and holding as part of a clean and sterile supply distribution system, the work counter and hand-washing facilities may be omitted. Soiled rooms shall be arranged separately from clean rooms or holding rooms.

b. Adequate storage space shall be provided for sterile and clean items; these spaces shall be provided with temperature and humidity controls and shall be located away from cross-traffic corridors.

c. A surgical suite with a sterile core shall be located so that the routes of staff and materials from the soiled area to the clean area do not cross. Where facilities outside the operating room are used to process soiled items, the packaging and sterilization process for clean items shall be designed so that the flow of personnel and materials proceeds from the soiled area to the clean or sterile area, without the need for pre-treatment measures or sterilization techniques in either area.

7.7.C8　Medical gas storage facilities. The principal storage room for medical gases may be located inside or outside the facility in accordance with NFPA 99. A separate storage room for at least a one-day supply of medical gases shall be provided.

7.7.C9　An anesthesia workroom for cleaning, testing, and storing anesthesia equipment shall contain work counters, a sink, and racks for cylinders. Separate storage shall be provided for clean and soiled items. In new construction, the provision of an anesthesia workroom, anesthesia carts, and other anesthesia equipment shall be determined by the functional and space program.

7.7.C10　Equipment storage room for equipment used in surgery.

7.7.C11　Staff dressing rooms. Suitable areas shall be provided for male and female staff (attending physicians, technicians, nurses, and residents) working in the surgical suite. These areas shall include lockers, bathing facilities, toilets, hand-washing facilities, and rooms for changing into surgical attire; these rooms shall be arranged on a one-way traffic pattern so that staff entering from outside the surgical suite can enter the suite directly.

7.7.C12　Staff lounge and sanitary facilities. Separate or connecting lounges shall be provided for male and female staff. The lounges shall be located so that, as far as possible, staff need not remove their outer garments to enter, and shall provide convenient access to the recovery room.

7.7.C13　Consultation and reporting rooms may be located in the lounge area.

7.7.C14　Outpatient recovery room. Where the functional program includes outpatient surgery, separate outpatient recovery areas shall be divided into two categories: (Category I) patients receiving general anesthesia and (Category II) patients not receiving general anesthesia. These requirements may be met by providing separate rooms. Category II areas shall ensure the privacy of each patient and shall include a patient toilet accessible directly from the outpatient recovery room. No more than two minor surgical facilities may use the Category II patient recovery room (for patients not receiving general anesthesia) as a pre-anesthesia room for the operating room.

7.7.C15　Dressing rooms for outpatients and same-day admission patients. Where the functional program designates outpatient surgery as part of the surgical suite, separate rooms shall be provided for outpatients to change from street clothes into hospital patient attire and to be prepared for treatment. These shall include a waiting area, lockers, toilets, and dressing rooms. Dressing rooms may be located in a concealed holding room or in cubicles.

7.7.C16　Provisions shall be made for outpatient surgery for patient examination, consultation, preparation, testing, and observation of vital signs.

7.7.C18　Storage rooms shall be provided for portable X-ray equipment, stretchers, fracture fixation devices, heating units, auxiliary lights, and similar items. These rooms shall be located away from corridors and traffic. 7.7.C19 Cleaning equipment. Cleaning equipment dedicated to the surgical suite shall be provided. It shall be directly accessible from the surgical suite and shall include a service sink or floor drain and a storage room for supplies and cleaning equipment.

7.7.C20 Frozen section preparation and examination room. Where results are required immediately upon completion of surgery and cannot be delayed, this room may be part of a general laboratory.

7.7.C21 Ice machine. An ice machine shall be provided for treatment and for patient use. Ice for patient use shall be obtained from an automatic dispenser.

7.7.C22 Refrigerated blood bank.

7.7.C23 Conveniently accessible refrigerated facilities for the storage of organs.

7.7.C24 A storage room shall be provided for pathological specimens prior to their transfer to the pathology department.

7.31 Mechanical Standards

7.31.A General

7.31.A1 Mechanical systems shall be designed to meet requirements for overall operational efficiency and reasonable life-cycle costs. The details of design component costs are interrelated and numerous (and too specific) to be listed separately. To achieve the most economical and efficient results, the designated engineering approach shall be followed. Well-designed systems can usually achieve higher efficiency at minimal additional cost while providing more comfortable conditions for patients. Climatic and usage conditions at different geographic locations may favor different systems in terms of cost and efficiency. Energy conservation shall not compromise patient care and safety conditions.

Mechanical, electrical, and HVAC equipment may be located indoors or outdoors and in separate buildings.

7.31.A2 Retrofit of existing facilities may present special problems. Where practical conditions and funding permit, existing insulation, climatic zones, etc. shall meet the standard requirements for maximum economy and efficiency. Additional work shall be considered in order to meet these requirements.

7.31.A3 Design considerations for the facility shall include the building, orientation, configuration, fenestration, and other features related to passive and active energy systems.

7.31.A4 In implementation, the facility shall be provided with waste cooling and waste heat recovery facilities (ventilation, exhaust gas, water and steam discharge, cooling towers, incinerators, etc.).

7.31.A5 The design of the facility shall take into account proven energy conservation mechanisms, such as variable air volume systems, overload protection, programmed control during non-operating periods (nights and weekends), and utilization of natural ventilation, geographic location, and climatic conditions. Systems that are detrimental to long-term energy conservation while requiring increased installation and maintenance costs shall be avoided.

7.31.A6 Air-handling systems shall be provided with energy-saving cycles that make rational use of outdoor fresh air (mechanical cycles utilizing outdoor fresh air shall not be without filters). In many locations, under appropriate climatic conditions, mechanical ventilation may be reduced or shut off and windows opened to utilize natural ventilation.

7.31.A7 Mechanical equipment, ducts, and piping shall be installed on vibration isolation devices as required to prevent unacceptable structural vibration.

7.31.A8 Supply and return mains and branch lines of cold water, hot water, and steam systems shall all be equipped with valves to isolate each branch of each system. Each piece of equipment shall be provided with valves at both the supply and return terminals.

7.31.B Thermal Insulation and Sound Insulation

7.31.B1 Building insulation shall be provided for energy conservation, personnel safety, prevention of steam condensation, and noise reduction.

7.31.B2 Insulation of cold surfaces shall include an exterior vapor barrier (materials that neither absorb nor transmit moisture may omit the vapor retarder). 7.31.B3　Insulation, including decorative finishes and insulation adhered to the outer surfaces of ducts, water pipes, and equipment, shall have a flame spread rating of not greater than 25 and a smoke developed rating of not greater than 50, as determined by an independent testing laboratory in accordance with NFPA 255.

7.31.B4　If duct liners are used, the coating shall be sealed and shall comply with ASTM C1071. These duct liners (including the coating, adhesives, and insulation on the outer surfaces of water pipes and ducts within supply air plenums) shall have a flame spread rating of not more than 25 and a smoke developed rating of not more than 50, as determined by an independent testing laboratory in accordance with NFPA 255. In renovation work, if existing duct liners are modified, the joints and cut ends of the liners shall be re-insulated.

7.31.B5　Service lines for operating rooms, delivery rooms, nursing rooms, protective environment rooms, and special care units shall not be exposed to the air. This requirement shall not apply to mixing boxes and sound attenuators whose service lines have an independent coating.

7.31.B6　Existing insulation in areas where equipment is updated shall be properly inspected, repaired, or replaced.

7.31.B7　Duct liners shall not be installed within 15 ft (4.57 m) downstream of a humidifier.

7.31.C　Steam and Hot Water Systems

7.31.C1　Boiler capacity shall be based on the net rating published by the Hydronics Institute or on the capacity specified by another applicable national standard, so as to meet the normal heating, hot water, and steam requirements of all systems and equipment. The number and arrangement of boilers shall be such that the facility's needs can still be met should any one boiler fail or be out of service for routine maintenance. The capacity of the remaining boilers shall be sufficient to provide hot water for clinical, dietary, and patient use; steam for sterilization and dietary purposes; and heating for operating rooms, delivery rooms, nurseries, labor rooms, recovery rooms, special treatment rooms, nursing units, and general patient rooms. However, in geographic areas where the design dry-bulb temperature, as listed in the "Climatic Conditions for the United States" table in the ASHRAE Design Handbook, is 25°F (−4°C) or higher for no less than 99% of the total hours of each heating season, standby capacity for space heating need not be designed.

7.31.C2　Boiler accessories, including feed pumps, hot water circulating pumps, condensate return pumps, oil pumps, and waste heat boilers, shall be installed for standby service.

7.31.D　Air-Conditioning, Heating, and Ventilating Systems

7.31.D1　All rooms and areas used by patients in the hospital shall be provided with ventilation systems. The ventilation rates shown in Table 2 are intended only as minimum standards and do not preclude the use of higher, more appropriate ventilation rates. Where the weather permits, natural ventilation may be used in areas and patient rooms with low air-conditioning requirements. Exhaust fans shall be located at the end of the exhaust system and be readily accessible. For rooms for which no minimum total ventilation rate is specified, the supply and exhaust air quantities may vary with the room load down to zero. For rooms listed in Table 2 that use variable air volume (VAV) systems, the minimum ventilation rates shall be within the stated limits. Ventilation systems shall be designed and balanced in accordance with the requirements of Table 2 and applicable guidelines.

7.31.D2　Exhaust systems may be combined with the recovery devices needed for energy conservation to improve efficiency. Where possible, local exhaust systems may be used in place of dilution ventilation systems to reduce the spread of noxious gases, vapors, smoke, or mist.

7.31.D3　Outdoor air intakes shall be located at least 25 ft (7.62 m) from the exhaust outlets of ventilating systems, the stacks of combustion equipment, medical-surgical vacuum systems, sealed openings, or areas where vehicular exhaust or other noxious gases may be drawn in. (Greater separation distances may be required where the intake is in the prevailing wind direction or near other buildings.) Exhaust and vacuum vents opened above the outdoor air intake shall be located at least 10 ft (3.05 m) from it. The bottom of outdoor air intakes serving central systems shall be located as high as possible, but at least 6 ft (1.83 m) above the ground. If installed on the roof, they shall be at least 3 ft (91 cm) above the roof. Exhaust outlets in locations where contamination may occur shall be located on the roof and arranged in a manner that minimizes the possibility of exhaust air recirculating into the building.

7.31.D4　In new construction and major renovation, supply air for operating rooms and delivery rooms shall be introduced from ceiling supply outlets located near the center of the work area. Return air shall be near floor level. Each operating room and delivery room shall have at least two return air inlets, spaced as far apart as possible. (The design shall take into account turbulence and other factors of air movement to minimize the settling of particulates onto sterile surfaces.) Certain special procedures, such as organ transplantation, require special design and installation and shall meet the performance requirements determined by applicable standards. requirement. These special designs should be reviewed on a case-by-case basis.

7.31.D5 Supply air outlets for rooms where infectious procedures are performed should be located in or near the ceiling. Return or exhaust outlets should be located near the floor. Exhaust grilles for anesthetic gas scavenging and other special applications should be permitted to be installed in the ceiling.

7.31.D6 Each area where inhalation anesthetics and analgesics are controlled should be provided with a scavenging system to remove waste gases. If a vacuum system is used, the gas collection system should be located where it will not interfere with the patient's respiratory system, and the gases from the scavenging system should be discharged directly outdoors. If the exhaust used for anesthetic gas removal is discharged directly outdoors and is not a recirculating system, then the anesthetic gas removal system should be connected to the room exhaust system. Scavenging systems are not required for areas where anesthetic gases are used only occasionally, such as emergency rooms and routine dental offices. To date, acceptable concentrations of anesthetic agents remain unknown. Due to the lack of specific data, it is quite difficult to establish definitive standards. However, any scavenging system should be designed to remove as much gas as possible from the indoor environment. It is generally considered that anesthetic equipment with low leakage, minimal indoor contamination, and ease of maintenance should be selected.

7.31.D7 The bottom of air outlets (supply/return) should be at least 3 in. above the floor.

7.31.D8 The filter efficiency provided in any central ventilation and air-conditioning system should be equal to or higher than the values given in Table 3. (Note: This table is Table 3 given in that standard, which differs from domestic standards, so the values given therein are omitted.) If two-stage filtration is required, the first-stage filter should be located upstream of the air-conditioning equipment; the second-stage filter should be located downstream of all fans. Filter efficiency measured in accordance with ASHRAE 52-92 should be the average value. Filter holding frames should be sturdy and durable and equipped with sealing gaskets matched to their dimensions. All connections between filter components and closed ductwork should have gaskets or sealing rings to prevent air leakage. Pressure gauges should be installed on all filter housings requiring filtration efficiency of 75% or greater, including supply air outlets requiring HEPA filters.

7.31.D9 If a duct humidifier is located upstream of the terminal filter, it should be at least 15 ft (4.57 m) upstream of the terminal filter. Ductwork with duct humidifiers should have facilities for eliminating entrained droplets. An adjustable high-limit humidistat should be installed downstream of the humidifier to reduce potential condensation in the duct. All drain pipes should be located far enough downstream of the humidifier to ensure complete moisture absorption. Steam humidifiers should be used; reservoir-type spray humidifiers or evaporative panel humidifiers should not be used.

7.31.D10 Air-handling systems should be designed in a form that is easy to clean and meets the requirements of NFPA 90A.

7.31.D11 When ductwork penetrates protective structures designed to shield against X-rays, magnetic fields, electrical fields, or other radiation hazards, the protective performance of these structures should not be compromised.

7.31.D12 Fire dampers and smoke dampers should be provided, located, and installed in accordance with NFPA 101, 90A, and the specific requirements for the dampers. To prevent damper operation from damaging the ductwork, fans, dampers, and detectors should be interconnected. All dampers should be located in positions convenient for personnel to operate. The locations of all dampers should be shown on the design drawings. Dampers should be capable of being controlled by fire or smoke sensing devices, not merely by the return fan. A switch system for restarting the fans should be installed so that, after the fire has been controlled, the fire department can use the system for smoke exhaust. However, damage to the system caused by closing dampers should be avoided as much as possible. Where smoke barriers are required, the heating, ventilation, and air-conditioning zones in the actual design should coincide with the smoke compartments in order to minimize penetrations through fire or smoke barriers (walls).

7.31.D13 If minimum ventilation rates are maintained, exhaust hoods or safety cabinets may be used for routine exhaust of the area. If the ventilation rate criteria in Table 2 cannot provide sufficient air for the proper operation of exhaust hoods and safety cabinets (when in use), a makeup air system (with filters and preheaters) should be provided around these devices to maintain the required airflow direction and exhaust velocity. The makeup air system should avoid introducing unfiltered outdoor air or air from contaminated areas. The makeup air system for exhaust hoods should be designed in a manner that minimizes air "short-circuiting" and avoids reduction of air velocity at the contaminant capture hood.

7.31.D14 Laboratory exhaust hoods should meet the following general criteria: a The average face velocity shall be at least 75 ft/min (0.38 m/s).

b It shall be connected to the building exhaust system.

c An exhaust fan shall be provided at the discharge end of the system.

d A noncombustible, corrosion-resistant exhaust ductwork system shall be used that meets the requirements of the intended use of the exhaust hood.

7.31.D15 Laboratory fume hoods shall meet the following special standards:

a Hoods used for perchloric acid and other strong oxidizing agent gases, and their accessory equipment, shall be constructed with special surfaces of stainless steel or other materials, and shall be equipped with wash-down and drainage systems for periodic cleaning of the ducts and hoods. Electrical equipment installed in these ducts shall be designed in a waterproof configuration. Lubricants and seals shall not contain organic materials. Where perchloric acid or other strong oxidizing agent gases are only transferred from one container to another, standard laboratory hoods and their accessories may be used in lieu of stainless steel construction.

b In new construction and major renovation projects, each hood used for handling infectious or radioactive materials shall have a face velocity of at least 90 to 110 ft/min (0.45 to 0.56 m/s) and shall be equipped with suitable pressure-independent air-volume control devices and audible and visual alarms to alert health care staff of fan shutdown or reduction in airflow. Each hood shall be equipped at the exhaust end with a filter having an efficiency of 99.97% (based on the dioctyl phthalate [DOP] test method), and the filter shall be designed so that it can be safely removed, disposed of, and replaced after use. Filters shall be located as close to the hood as possible to minimize contamination of the ductwork. Hoods used for handling radioactive isotopes shall be constructed of stainless steel or other suitable exposed materials and shall meet the requirements of NFPA 801, "Facilities Handling Radioactive Materials." Note: Radioactive isotopes for injection that are free of aerosols or gases, etc., may be handled in clean-bench-type hoods as permitted by the Nuclear Regulatory Commission.

7.31.D16 Exhaust hoods in food preparation centers that remove grease-laden vapors shall comply with NFPA 96. All exhaust hoods above cooking areas shall be equipped with grease filters, fire-extinguishing systems, and controls for heat-activated fans. Cleanouts shall be provided every 20 ft (6.10 m) and at each change of direction in the horizontal exhaust ducts serving these hoods. (Horizontal ducts serving hoods in parallel shall be kept as short as possible.)

7.31.D17 Ventilation systems for rooms where anesthetic agents are stored shall comply with NFPA 99, including provisions relating to gravity. Mechanical ventilation systems shall be selected for such rooms.

7.31.D18 Ventilation systems for spaces housing ethylene oxide (ETO) sterilizers shall be designed as follows:

a A dedicated exhaust system shall be provided (not connected to any other return-air or exhaust system); see 29 CFR 1910.1047.

b All sources of toxic emissions, including the room housing the sterilizing equipment, service or ventilation areas, the area above the sterilizer door, and the sterilizer aeration chamber, shall be exhausted. If ETO storage tanks are not located in a well-ventilated area containing no other equipment, an exhaust hood shall be provided above the tanks. Safety relief valves shall be located in a well-ventilated, equipment-free area or outside the building. Floor drains serving sterilizing equipment, if not located in a well-ventilated equipment-free area, shall be provided with an exhaust hood (per local codes).

c Ensure that the normal airflow is from the sterilizer operator toward the exhaust hood.

d A dedicated exhaust duct system shall be provided for ETO. The exhaust outlet shall be located at least 25 ft (7.62 m) from the outdoor-air intake.

7.31.D19 If the exhaust system leaks air, the audible and visual alarms in the sterilizer work area and the 24-hour work area shall sound.

7.31.D20 Sufficient outdoor air shall be provided for rooms containing combustion equipment to maintain the firing rate of the equipment and to limit the temperature of the combustion equipment room.

7.31.D21 Where conditions permit, natural ventilation may be used in patient-free areas such as boiler rooms, central storage areas, and similar spaces. 7.31.D22 The energy-saving potential of variable air volume (VAV) systems has been recognized, and such systems should be used to the maximum extent possible.

7.31.D23 Special consideration should be given to the type of heating and cooling units, vents, and appurtenances located in patient residing areas of psychiatric treatment departments. The following should be used:

a Louvers and diffusers should be of a type that prevents the lodgment of foreign objects. All exposed fasteners should be tamper-proof.

b All exposed in-room convectors and HVAC appurtenances should have rounded corners and should be equipped with protective guards fitted with tamper-proof bolts.

c In-room HVAC equipment should be of a type that requires minimal maintenance.

7.31.D24 Rooms or booths used for suctioning, aerosol treatments, and other procedures that readily induce coughing should be provided with local exhaust systems; see the ventilation requirements in Table 2.

7.31.D25 Non-central air handling systems, i.e., room-distributed units (fan coil units, heat pump units, etc.) installed for room heating and cooling, should be equipped with permanent or replaceable filters. Filters should have a minimum weight arrestance efficiency of 68%. All outdoor air should be supplied by dispersed central air handling systems equipped with filters.

7.31.E Plumbing and Other Piping Systems

Unless otherwise specified herein, all plumbing systems should be designed and installed in accordance with the National Standard Plumbing Code.

7.31.E1 The following criteria should apply to plumbing fixtures.

a Materials used for plumbing fixtures should be non-absorbent and acid-resistant.

b The distance between the faucets of lavatories and sinks should be adequate to avoid contamination of the fixtures and liquids in glass bottles.

c Handwashing facilities for daily use by medical and nursing staff, all lavatories used by patients, and food processors should be fitted with shutoff valves. These valves should be operable without hands, and their handles should be longer than $4frac{1}{2}$ in (11.43 cm). Handles on clinical sinks should be at least 6 in long. Separate scrub sinks and lavatories used for scrubbing in operating rooms should be hand-, foot-, or ultrasonically operated.

d Clinical sinks should have an integral trap, and the upper portion of the trap should be provided with a visible seal.

e Showers and bathtubs should have nonslip walking areas.

7.31.E2 The following criteria apply to potable water supply systems.

a Systems should be designed to provide the water pressure required for all equipment and fixtures operating under maximum demand conditions. The water supply capacity of hot and cold water piping should be determined by the fixtures in accordance with the specified engineering standards. Where the ratio of plumbing fixtures to occupied area is greater than that required by the building occupancy and the number of plumbing fixtures exceeds 1000, ratios other than the prescribed values are permitted.

b Valves should be installed in the main, branch mains, risers, and branches connected to each fixture of the water supply system. A shutoff valve should be installed at each fixture. Where required, appropriate baffles should be installed on all valves.

c Vacuum breakers should be installed on hose bibbs and nozzles with hose or piping connections used for lavatories, service sinks, bedpan flushing attachments, and autopsy tables.

d A bedpan flushing device should be provided in each inpatient toilet room; however, it may be omitted in wards for ambulatory psychiatric and alcoholic patients.

e Potable water storage facilities (hot and cold) that are not frequently used should not be installed.

7.31.E3 The following criteria apply to hot water systems.

a The capacity of the hot water system should be determined on the basis of the temperatures and quantities given in Table 4 (omitted). Water temperatures are measured at the point of use or at the entrance to the equipment.

b Hot water distribution systems supplying patient treatment areas should be kept in constant circulation to provide continuous hot water. The hot water temperature in shower rooms and bathrooms shall ensure comfortable use but shall not exceed 110℉ (43℃).

7.31.E4　The following criteria apply to drainage systems:

a Drainage piping from sinks handling acid waste shall be made of acid-resistant materials.

b Drainage piping from some automated blood cell counters must be made of carefully selected materials to prevent chemical reactions between sodium bicarbonate waste and copper, lead, brass, solder, and the like.

c In operating rooms, delivery rooms, nursing care rooms, food preparation centers, food service facilities, food storage areas, major service areas, electronic data processing rooms, electronics rooms, and other sensitive areas, drainage piping shall not be installed in ceilings or exposed within the rooms wherever possible. Where exposed overhead drainage piping is unavoidable in these areas, provisions shall be made to prevent contamination of the space by leakage, condensation, or falling dust.

d Floor drains shall not be provided in operating rooms and delivery rooms.

e Where floor drains are provided in oncology rooms, a non-splashing, horizontal-flow flush sink shall be provided at the bottom of the drain basin.

f The drainage system of autopsy tables shall be designed in a form that avoids splashing or overflowing onto the floor or back-siphonage, and that is easy to clean and flush.

g Building sewage shall be discharged to the community sewage system. Where such a sewage system is not available, the hospital shall treat the sewage in accordance with local and state codes.

h Kitchen grease wells shall be located in positions that can be conveniently accessed without entering food preparation or storage rooms. Grease wells shall have the required capacity and shall be accessible from outside the building without disturbing the service areas.

i Where plastic grease wells are used, provisions shall be made for easy access and cleaning.

j In dietary areas, floor drains or floor sinks shall be of a type that allows the covers to be removed for cleaning. Floor drains or floor sinks required for floor cleaning shall be provided at all "wet" equipment (such as ice machines). In addition to strainer drain covers, removable stainless steel mesh shall be provided to prevent the entry of large-particle waste that could cause blockage. Floor drains and floor sinks shall not be located in positions where it is difficult to remove the covers for cleaning.

7.31.E5　The installation, testing, and certification of nonflammable medical gas and air systems shall comply with the requirements of NFPA99.

7.31.E6　The installation of clinical vacuum systems shall comply with the provisions of NFPA99.

7.31.E7　All piping, except control line piping, shall be verified; all valves shall be labeled; and a valve schedule shall be provided to the facility owner for record and reference.

7.31.E8　Where the functional program includes hemodialysis, continuously circulated and filtered cold water shall be provided.

7.31.E9　Condensate drains shall be provided for cooling coils that can be cleaned in place when necessary (condensate drains need not be trapped unless specifically required by the local authority). An air gap shall be provided where condensate drains discharge into floor drains. Heating elements shall be provided for condensate lines in cold storage rooms or other areas subject to freezing problems.

7.31.E10　Plumbing systems shall not be exposed overhead or on walls in locations where dust or oil may accumulate, creating sanitation problems, or where leakage could result in possible food contamination.

7.32　Electrical Standards

7.32.A　General Provisions

7.32.A1　All electrical materials and equipment, including command, control, and signaling equipment, shall be installed in accordance with NFPA70 and the applicable sections of NFPA99, and shall be listed in the schedule in accordance with the distributor's standards or other similar standards.

7.32.A2　Certain electrical devices, including alarms, nurse call and communication systems, shall be tested to demonstrate that installation and operation are no normal. Written records of performance testing for special electronic systems and equipment shall specify the appropriate standards and criteria followed.

7.32.A3 Where interference from power lines may affect data processing, or at automated laboratory equipment or diagnostic equipment, shielded isolation transformers, voltage regulators, filters, overvoltage suppressors, and other safety devices shall be provided as required.

7.32.B Service and Switching Control Boards

The main switching control boards shall be located in areas separated from piping and other mechanical equipment, and shall be operated only by the responsible personnel concerned. Switchboards shall be convenient to use and easily accessible for maintenance, located away from traffic corridors, and placed in dry, ventilated spaces free of explosive gases and any combustible materials. Overload protection equipment shall function properly at the ambient temperature of the room.

7.32.C Panelboards

Panelboards for normal lighting and equipment circuits shall be located on the same floor as the circuits they serve. Panelboards for critical branch emergency circuits shall be located on the floor where the principal users (operating rooms, delivery, intensive care rooms, etc.) are located. Circuits for life safety emergencies shall also provide service to the floor above or the floor below.

7.32.D Lighting

7.32.D1 The Illuminating Engineering Society of North America (IES) has published recommended standards for lighting in health care facilities; readers may refer to the IES Handbook.

7.32.D2 Entrance halls leading to buildings and parking areas, as well as all usable spaces within buildings, shall be provided with lighting as needed.

7.32.D3 Patient rooms shall have general lighting and night lighting. A table lamp shall be provided for each patient. The switch of the table lamp shall be easy for the patient to control. Heat-generating incandescent lamps and halogen lamps shall be avoided to prevent burning patients or scorching linen bedding. Light sources shall be enclosed with diffusers or lenses. If movable lamp arms are used, mechanical controls shall be provided to prevent the lamp from coming into contact with linen bedding. Each patient room shall have at least one night light that can be switched on and off at the room entrance. The lighting at the bed areas of coronary care patients and special care patients shall enable medical staff to observe the patients under minimal light.

7.32.D4 In addition to the special lighting fixtures installed on the operating tables and delivery tables, operating rooms and delivery rooms shall also be provided with general lighting. The general lighting and the special lighting shall be on separate circuits.

7.32.D5 Corridors in nursing units shall be provided with general lighting, together with switches that allow the brightness to be reduced at night.

7.32.D6 Lighting for medical staff and patients shall generally comply with the health care standards established in the IES edition. Consideration shall be given to controlling the light intensity or wavelength to prevent damage to patients' eyes (i.e., damage to the retinas of premature infants and cataract patients caused by excessive brightness).

Many measures may be adopted to satisfy the lighting requirements, but the design should take into account the quality and quantity of light required for effectiveness and efficiency. Since the IES edition is referenced here for lighting levels, designers should be encouraged to use publications that include other useful criteria and recommendations.

7.32.D7 Special consideration shall be given to the particular requirements of middle-aged and elderly people. The use of excessive brightness levels that are difficult for visual adaptation shall be minimized.

7.32.D8 Portable or fixed examination lights shall be provided for examination, treatment, and trauma areas.

7.32.D9 The light levels required for emergency department lighting shall generally conform to the IES recommendations. Lighting at entrances and exits shall comply with the requirements of NF-PA101.

7.32.E Outlets

7.32.E1 Each operating room and delivery room shall have at least 6 outlets located near the front of the work table.

Each operating room shall have at least 16 single or 8 duplex outlets. Where movable X-ray equipment requiring special electrical configurations is used machines, laser devices, or other equipment, additional outlets dedicated to X-ray machines or laser devices shall be provided.

7.32.E2 Each patient room shall be provided with duplex floor outlets. One shall be provided on each side at the front of each patient bed; if there is a television, one shall be for the television and one on the wall. Where the structure or room arrangement does not permit, the outlets on the exterior wall may be omitted. Nursing rooms shall have at least 2 duplex floor outlets for each bassinet. In major care areas as defined by NFPA99 and NFPA70, including pediatric and newborn special care areas, at least 7 duplex outlets shall be provided at the front of each bed, i.e., crib or bassinet. Trauma and recovery rooms shall have 8 duplex outlets near the front of each bed. Examination and treatment rooms of the emergency department shall have a minimum of 6 duplex outlets near the front of each bed. Approximately 50% of the major and emergency care outlets shall be connected to the emergency system station and labeled. Each general care examination and treatment table and each work table shall be provided with 2 duplex outlets.

7.32.E3 General-purpose duplex floor outlets installed in all corridors shall be spaced approximately 50ft(15.24m) apart and shall be located within 25ft(7.62m) of the corridor ends. Outlets installed in the corridors of pediatric and psychiatric departments shall be of a tamper-resistant safety type. Special outlets dedicated to X-ray machines shall be installed in the corridors of patient room areas so that movable equipment can be connected with a cord of 50ft(15.24m) or shorter from any location in the patient rooms. If the same movable X-ray equipment is used in operating rooms and nursing rooms, the outlet used for the X-ray machine shall permit the plug to be used at any location. Where rechargeable or battery-powered X-ray machines are used, the special outlets for X-ray machines may be omitted.

7.32.E4 The electrical outlet cover plates or electrical outlets of the emergency system shall be painted with a distinctive color or marking. If color is used as the marking, the same color shall be used throughout the hospital.

7.32.E5 In kidney dialysis rooms, 2 duplex outlets shall be provided on each side of the patient bed or reclining chair. One duplex outlet on each side of the patient bed shall be connected to the emergency station.

7.32.F Equipment

7.32.F1 In inhalation anesthesia rooms, all electronic equipment and devices, outlets, and wiring shall comply with the requirements of the applicable sections of NFPA99 and NFPA70.

7.32.F2 The installation of fixed and movable X-ray equipment shall be carried out in accordance with Articles 517 and 660 of NFPA70.

7.32.F3 In each operating room, dedicated emergency treatment room, and X-ray viewing room of the radiology department, X-ray film illuminators or equipment capable of displaying at least 2 films simultaneously shall be installed. All viewing lights in a room or space shall provide illumination of uniform intensity and color.

7.32.F4 Ground-fault circuit interrupters (GFCI) shall comply with the requirements of NFPA70. If ground-fault circuit interrupters are used in major areas, measures shall be provided to ensure that other essential equipment is not affected by the tripping of the interrupters.

7.32.F5 In areas such as major treatment units and special care units where patients may be treated with an invasive probe or a catheter connected to the heart, the grounding system shall comply with the requirements of the applicable sections of NFPA99 and NFPA70.

7.32.F6 Testing shall be performed for the following departments and special equipment: major care units, newborn care rooms, pediatric and adolescent departments, psychiatric care units, surgery, obstetrics, emergency service rooms, radiography rooms, medical radiology department, laboratories, rehabilitation therapy department, kidney dialysis rooms, respiratory therapy service rooms, data rooms, pharmacy, dietary facilities, administrative and public areas, medical records rooms, central service areas, general supply storage rooms, linen service supply facilities, etc.

These departments shall consult with one another to ensure compatibility between the equipment needs determined by the functional program and the appropriate electrical and other electronic connection requirements.

7.32.F7 Special safety measures shall be provided to protect equipment cables from hazards. Where possible, every effort shall be made to minimize these hazards.

7.32.G　Nurse Call System

7.32.G1　In patient room areas, a two-way communication call system shall be provided for each patient room at a minimum. A call device shall be provided at each patient bed. One call station may serve two call devices for adjacent beds. The call device shall be capable of activating visual signals in the patient room corridor, clean workroom, soiled workroom, medication room, charting room, clean linen storage room, nourishment room, equipment storage room, examination or treatment room, and the nursing station of the nursing unit. Nursing units with multiple corridors shall have additional visual signals installed at corridor intersections. In rooms with two or more call stations, an indicator light shall be provided at each station. The nurse call system for each call station shall be equipped with an indicator light that remains lit once the sound circuit has been activated.

7.32.G2　Nurse emergency call systems shall be provided in all inpatient toilets, bathrooms, and shower rooms. The nurse emergency call device shall be usable by a patient who has fallen to the floor. A system equipped with a pull cord can meet this requirement.

The emergency call system shall be designed in the form of audible and visual signals that are activated by a signal initiated at the patient call station, that are different from those of the normal nurse call system, and that can be turned off only at the patient call station. The signal shall be capable of activating a bell at the nurses' station and visual signals in the corridors of patient rooms and of other areas designated by the functional program. Emergency call devices shall also be provided in outpatient rooms and treatment areas where patients may become incapacitated.

7.32.G3　In central treatment, recovery, and surgical preparation room areas where patients are under continuous care, the nurse call system may consist of a button at the bedside or a device capable of emitting a signal visible in the control room.

7.32.G4　In each operating room, delivery room, recovery room, emergency examination or treatment room, central nursing unit, nurses' station, special workroom, cardiac catheterization room, stress testing area, triage room, outpatient surgery area, admission and discharge area, psychiatric patient area (including seclusion rooms and secure rooms), lounge and the toilets serving it, public toilets and shower facilities, dining room, activity room, medication room, and examination and treatment room, a staff emergency assistance system shall be provided for medical staff to summon assistance. This system shall display visual and audible signals in the clean workrooms, soiled workrooms, medication rooms, charting rooms, clean linen storage rooms, nourishment rooms, equipment storage rooms, and examination/treatment rooms where the system is provided, as well as at the nurses' stations of nursing units in medical staff areas capable of providing assistants who can be summoned to respond.

7.32.G5　In central nursing, recovery, and surgical preparation rooms, the call system shall include an emergency signal alarm facility for summoning assistance from outside the unit.

7.32.G6　Nurse call systems are not required in psychiatric nursing units; however, where provided, facilities shall be provided to allow the call button to be easily opened or covered. In psychiatric nursing units, all hardware shall be equipped with tamper-resistant fasteners to prevent tampering.

7.32.G7　A nurse emergency call system shall be provided in the patient toilet of the radiography room.

7.32.G8　Toilets in the renal dialysis room shall be equipped with an emergency call system. The call system shall be capable of activating a signal at the nurses' station.

7.32.G9　Other technological facilities may be considered for emergency or nurse call systems. If radio frequency transmitting systems are used, electromagnetic compatibility between internal and external sources shall be considered.

7.32.H　Emergency Power Service Facilities

Emergency power stations shall be provided in accordance with NFPA99, NFPA101, and NFPA110.

7.32.I　Fire Alarm

All health care buildings shall be provided with fire alarm systems in accordance with NFPA101 and NFPA72.

7.32.J　Telecommunications and Information Systems

7.32.J1　Space shall be provided for telecommunications and information systems equipment.

7.32.J2　A room shall be provided to house the central equipment. If recommended by the manufacturer, special air conditioning and voltage regulators shall be provided.

Table 2 Ventilation Requirements for Areas Affecting Patient Care in Hospitals and Outpatient Facilities¹⁾

Area Name Air Movement Relationship with Adjacent Areas²⁾ Minimum Outdoor Air Changes per Hour³⁾ Minimum Total Air Changes per Hour⁴⁾ All Exhaust Air Discharged Directly to Outdoors⁵⁾ Recirculated by Room Units⁶⁾ Relative Humidity⁷⁾/% Design Temperature⁸⁾/F(℃)
Surgical and Major Nursing Areas
Operating/Surgical Cystoscopy Room⁹⁾ Out 3 15 — No 30～60 68～73 (20～23)
Delivery Room⁹⁾ Out 3 15 — No 30～60 68～73 (20～23)
Recovery Room⁹⁾ — 2 6 — No 30～60 70(21)
Critical and Intensive Care — 2 6 — No 30～60 70～75 (21～24)
Treatment Room¹⁰⁾ — — 6 — — — 75(24)
Trauma Room¹⁰⁾ Out 3 15 — No 45～60 70～75 (21～24)
Anesthetic Gas Storage Room — — 8 Yes — — —
Endoscopy Room — 2 6 — No 30～60 68～73 (20～23)
Bronchoscopy Room In 2 12 Yes No 30～60 68～73 (20～23)
Nursing Areas
Patient Room — 2 2 — — — 70～75 (21～24)
Toilet Room In — 10 Yes — — —
Newborn Care Unit — 2 6 — No 30～60 75(24)
Protective Environment Room¹¹⁾ Out 2 12 — No — 75(24)
Airborne Infection Isolation Room¹²⁾ In 2 12 — No — 75(24)
Isolation Alcove or Anteroom¹¹⁾,¹²⁾ In/Out — 10 Yes No — —
Labor/Delivery/Recovery — 2 2 — — — 70～75 (21～24)
Labor/Delivery/Recovery/Postpartum — 2 2 — — — 70～75 (21～24)
Patient Corridor — — 2 — — — —
Support Areas
Radiology¹³⁾

Table 2 (continued)

Area name Air movement relationship with adjacent areas²⁾ Minimum outdoor air changes per hour³⁾ Minimum total air changes per hour⁴⁾ All exhaust air discharged directly to outdoors⁵⁾ Recirculated by room units⁶⁾ Relative humidity⁷⁾/% Design temperature⁸⁾/F(℃)
X-ray department (surgery/primary care and catheterization) Out 3 15 — No 30～60 70～75(21～24)
X-ray department (diagnostic and treatment) — — 6 — — — 75(24)
Darkroom In — 10 Yes No — —
Laboratory
General¹⁴⁾ — — 6 — — — 75(24)
Biochemistry¹⁴⁾ Out — 6 — No — 75(24)
Cytology In — 6 Yes No — 75(24)
Glassware washing room In — 10 Yes — — —
Histology In — 6 Yes No — 75(24)
Microbiology¹³⁾ In — 6 Yes No — 75(24)
Medical radiation department In — 6 Yes No — 75(24)
Pathology In — 6 Yes No — 75(24)
Serology Out — 6 — No — 75(24)
Sterilization room In — 10 Yes — — —
Morgue In — 12 Yes No — —
Non-refrigerated body storage room In — 10 Yes — — 70(21)
Pharmacy — — 4 — — — —
Diagnostic and treatment area
Examination room — — 6 — — — 75(24)
Medication room — — 4 — — —
Treatment room — — 6 — — — 75(24)
Physical therapy and hydrotherapy In — 6 — — — 75(24)
Soiled workroom or soiled holding room In — 10 Yes No — —
Clean workroom or clean supply holding room — — 4 — — — —
Sterilization and supply
Ethylene oxide sterilization room In — 10 Yes No 30～60 75(24)

Table 2 (Continued)

Area Name Air Movement Relationship with Adjacent Areas²⁾ Minimum Outdoor Air Changes per Hour³⁾ Minimum Total Air Changes per Hour⁴⁾ All Exhaust Air Discharged Directly to Outdoors⁵⁾ Recirculated by Room Units⁶⁾ Relative Humidity⁷⁾/% Design Temperature⁸⁾/F (℃)
Sterilizer Equipment Room In — 10 Yes — — —
Major Medical and Surgical Supply
Soiled or Contaminated Room In — 6 Yes No — 68～73 (20～23)
Clean Room Out — 4 — No 30～60 75(24)
Sterile Supply Storage Room — — 4 — — (Maximum) 70 —
Service Areas
Food Preparation Center¹⁴⁾ — — 10 — No — —
Merchandise Display Room In — 10 Yes No — —
Daily Food Storage Room In — 2 — — — —
Laundry, General — — 10 Yes — — —
Soiled Linen (Sort and Storage) In — 10 Yes No — —
Clean Linen Storage — — 2 — — — —
Soiled Linen and Trash Chute Rooms In — 10 Yes No — —
Bedpan Room In — 10 Yes — — —
Bathroom — — 10 — — — 75(24)
Janitor Closet In — 10 Yes No — —

1) The ventilation rates in the table include those ventilation rates that directly affect patient care comfort, asepsis, and odor control, and are determined on the basis that health care facilities are primarily "no-smoking" areas. Where smoking is permitted, the ventilation rates need to be adjusted. For areas for which specific ventilation rates are not given in the table, the ventilation rates shall be determined in accordance with ASHRAE Standard 62-1989, Ventilation for Acceptable Indoor Air Quality, and the ASHRAE Application Design Handbook. Special patient care areas, including organ transplant units, special workrooms of burn units, etc., shall provide appropriate additional ventilation for air quality control. OSHA standards and/or NIOSH standards for ensuring the health and safety of health care facility personnel all, requiring special ventilation rates.

2) The airflow pattern of ventilation systems should generally be designed so that air flows from cleaner areas to less clean areas. If any form of variable air volume or overload protection system is adopted for energy conservation, it must not disrupt the pressure balance relationship between corridors and rooms or the minimum ventilation rates specified in the table. Except where permitted by the provisions of NFPA90A concerning exit corridor spaces, in other areas the infiltration and exfiltration air quantities should not exceed 15% of the minimum total air quantity per hour or 50cfm, whichever is greater, as specified in the table.

3) To meet exhaust requirements, makeup air from outdoors is needed. Except for certain areas listed in the table, the table does not list specific outdoor makeup air quantities for individual areas. Good engineering practice requires that outdoor air be supplied to the ventilation system to balance the required exhaust air quantity. While the system is operating, the minimum outdoor air quantity should be maintained at a constant value.

4) If the air change quantity provided is intended to ensure that the specified air change rate can be achieved whenever the system is restarted at any time, the air change quantity may be reduced when the room is unoccupied. Regulating devices should be provided that can ensure the same airflow direction as before when the air change quantity is reduced. If the maximum infiltration or exfiltration permitted in Note 2) is not exceeded and the pressure balance with adjacent spaces is not disrupted, the ventilation system in areas not designated as requiring continuous directional airflow control may be shut off when the space is unoccupied or when a ventilation system is not required.

5) Air from contaminated or odorous areas should be exhausted to the outdoors and must not be recirculated to other areas. Note that certain areas, such as special care areas for patients with pulmonary infectious diseases and burn wards, require special consideration for the air exhausted to the outdoors.

6) Recirculating room HVAC units are local units used primarily for heating and cooling air without disinfecting the air. Because they are difficult to clean and may increase contamination, recirculating room units should not be used in areas marked "No." However, if HEPA filters are used, air may be recirculated within individual isolation rooms to achieve airborne infection control. Isolation rooms and individual care units may be ventilated by reheat units, in which only the primary air introduced from the central system passes through the reheat unit. Gravity-type heating or cooling devices such as radiators or convection heaters should not be used in operating rooms and other special care areas. For a description of recirculating units used in isolation rooms, see Appendix A (omitted).

7) The listed ranges are the minimum and maximum values requiring special control.

8) In areas with a specified temperature range, the ventilation system should be capable of keeping the temperature at any point in the room within that range. A single number indicates that the heating and cooling capacity should at least be able to meet the specified temperature value. These values are typically used when patients may be unclothed and require a warmer environment. Where patient comfort and medical conditions permit, this standard does not preclude the possibility of using temperatures lower than the specified values. Non-patient areas such as storage rooms should use temperature values appropriate to their intended function.

9) The occupational safety and health criteria documents of the national research institute concerning work environments with waste anesthetic gases, waste vapors, and nitrous oxide stipulate that in areas where these various gases are used, both a local exhaust system (scavenging system) and a general ventilation system are required.

10) The trauma section referred to in this document means the operating rooms of the emergency department or other areas used for emergency surgery that admit trauma patients. The first-aid room or "emergency room" used for the initial treatment of accident victims may have its ventilation system designed according to "Treatment Room" in the table. Treatment rooms used for bronchoscopy should have their ventilation systems designed in accordance with the requirements for bronchoscopy rooms. Treatment rooms used for nitrous oxide cryosurgery should be equipped with facilities for removing waste gases.

11) The airflow of protective environment rooms should be specially designed to protect patients from infection by airborne infectious microorganisms (i.e., Aspergillus spores) present in the general environment. The airflow pattern of these specially ventilated areas should be designed so that air flows directly from the cleanest patient care area to less clean areas. These rooms should be provided with HEPA filters having an efficiency of 99.97% for 0.3μm particles at the supply air side. These filters protect the room from contamination caused by the release of environmental microorganisms resulting from maintenance of ventilation components. Recirculating HEPA filters may be used to increase the equivalent room air change quantity. Protective environment rooms require constant volume ventilation systems. If the hospital considers that a patient in a protective environment room requires an airborne infection isolation room, such a room should be provided. Reversible airflow arrangements within the room for conversion between a protective environment room and an airborne infection isolation room are not permitted.

12) The infection isolation rooms in this guideline are used to isolate the airborne spread of infectious organisms such as measles, varicella (chickenpox), or tuberculosis. The design of the ventilation system for an airborne infection isolation room (AII) includes the facilities required for normal patient care during periods when isolation care is not needed. To increase the equivalent room air change quantity, supplemental recirculating devices may be used in the patient room; such recirculating devices cannot provide the required outdoor air quantity. If HEPA filters are used, air may be recirculated within the individual isolation room. Reversible airflow arrangements within the room for conversion between a protective environment room and an airborne infection isolation room (AII) are not permitted.

13) Where necessary, appropriate exhaust hoods and exhaust devices should be provided for the removal of toxic gases or chemical vapors.

14) The supply air of the ventilation system in the food preparation center should be interlocked with the exhaust hood or emergency exhaust so that the air infiltrating from or exfiltrating to exit corridors does not violate the restrictions on exit corridors in NFPA90A, the pressure requirements of NFPA96, or the maximum values established in the table. When the space is unoccupied, the air change quantity may be reduced or adjusted to any range required for odor control; see 7.31.D1.