Japan HEAS-02-1998: Guidelines for Design and Management of Hospital Air-Conditioning Equipment
2 Indoor Environment
2.1 Cleanliness Classification
2.1.1 Basic Policy
Each room (zone) within the facility shall be classified according to the cleanliness levels shown in Table 2.1-1, and the cleanliness suitable for the use of each room must be maintained.
In addition, when whole-hospital air conditioning is implemented, the zones of cleanliness levels Ⅰ, Ⅱ and Ⅲ must follow the criteria of these guidelines, while for zones of cleanliness level Ⅳ, compliance with these guidelines is also desirable.
For zones of cleanliness levels Ⅴ and Ⅵ, in accordance with their use and function, it is desirable to install dedicated mechanical exhaust equipment independent of other systems.
[Commentary]
(1) Although it would be most ideal to make all zones covered by the guidelines clean zones, this is in practice unreasonable as well as uneconomical. For this reason, it is rational to divide the hospital into several zones according to cleanliness (grade classification) and to adopt air-conditioning and ventilation systems appropriate to each grade.
(2) According to the required cleanliness and purpose, cleanliness is classified into grades Ⅰ to Ⅶ in the grade classification Table 2.1-1. The air-conditioning systems must also match this zoning as closely as possible.
(3) Whole-hospital air conditioning is desirable for hospital air conditioning; however, owing to reasons such as site selection conditions and insufficient construction funds, whole-hospital air conditioning may be omitted, and the scope of air conditioning may instead be expanded step by step in the order of cleanliness levels Ⅰ, Ⅱ, Ⅲ… shown in Table 2.1-1. For example, at first only the rooms of cleanliness levels Ⅰ to Ⅲ are air-conditioned, while zones Ⅳ and Ⅵ are still provided with direct heating and ventilation.
(4) In zones of cleanliness levels Ⅴ and Ⅶ, in order to prevent pollutants and the like from dispersing outdoors, systems shall be divided by rooms of the same use, and individual or centralized mechanical exhaust equipment shall be installed.
(5) The microbial counts shown as reference indicators in Table 2.1-1 were determined with reference to the Swiss hospital ventilation code.
(6) The cleanliness class classification and definitions of US Federal Standard 209 (the number of particles of 0.5 μm and larger per 1 ft³ of air) have been commonly used in our country. Since the work performed in hospital rooms varies greatly and different values may occur at the same measuring location, it is inappropriate to express cleanliness according to industrial cleanroom standards. For this reason, it is given only as a reference indicator and its adoption is avoided. For reference to the federal standard, a brief comparison of the particle counts within the nominal class and the microbial counts is shown in Figure 2.1-1 (omitted). In addition, the current air cleanliness codes of various countries are shown in Table 2.1-3 (omitted).
(7) The performance of terminal filters was determined with reference to the hospital codes of the United States, Germany, Switzerland and other countries. Under ordinary operating conditions, if filters meeting the minimum criteria in the table are used, the microbial counts in each room can generally be kept from exceeding the values given in the reference column.
2.1.2 Cleanliness Level Ⅰ (High-Cleanliness Zone)
In high-cleanliness zones, HEPA filters are used, and the vertical laminar flow or horizontal laminar flow method is applicable to biological cleanroom systems; positive pressure must be maintained with respect to the surrounding rooms.
The classification of air cleanliness by particle count originated with the US Federal Standard (Fed.Stc.209, first issued in 1963) and gained wide application. This standard was later revised several times (209A-D), and in 1992 the revised version NO.209E was published, adopting the SI system, in which the upper limit number of particles of the target particle size is clearly indicated.
The standard shown in Table 2.1-2, which is based on microbial counts, is that of the National Aeronautics and Space Administration (NASA) of the United States. Biological cleanrooms are classified into three classes—100, 1000, and 10000—and the maximum airborne microorganism counts in the air are specified as 0.1 count/ft³, 0.5 count/ft³, and 2.5 count/ft³, respectively.
As a method for measuring air cleanliness, a light-scattering particle counter can be used to measure the particle count instantaneously. This is more convenient than the measurement method that requires 20–40 h of bacterial colony cultivation. Therefore, if the proportion of bacteria and other microorganisms contained in the total airborne particles is constant, it is quite appropriate to estimate the bacterial concentration from the particle count. However, this proportion differs greatly depending on environmental conditions, for example between hospitals, office buildings, and electronic product factories, or between urban areas and mountainous areas. According to various comparative reports, accurate consistency has not been obtained.
However, a rough relationship can be seen within such a wide particle concentration range as Class M3.5 to M6.5 (Class 100 to Class 100000). In survey reports on the relationship between airborne particle counts and bacterial concentrations based on a large amount of data, the relationship shown in Figure 2.1-2 (omitted) is observed. For actual air, 95% of the values falling within the range of the dashed lines in the figure is taken as the bacterial concentration.
In addition, the NASA standard values are plotted in the figure, and the airborne bacteria measurements obtained with a pinhole sampler are in complete agreement with the counts of particles of 5 μm and larger. In many other reports as well, there are numerous cases in which the ratio of airborne particle count to bacterial count is proportional to the count of particles of 5 μm and larger. Therefore, if, in the same environment, the ratio between the concentration of particles of 5 μm and larger and the bacteria is known, the approximate bacterial concentration can be estimated by subsequently measuring the particle concentration with a particle counter.
2.1.3 Class II Cleanliness Level (Clean Area)
In the clean area, the air is purified by means of high-performance filters or HEPA filters, and appropriate positive pressure and airflow direction with respect to the surrounding rooms must be maintained.
[Commentary]
(1) For areas that meet cleanliness requirements, such as general operating rooms, preparation rooms, and sterilization rooms, the required cleanliness level of each room is lower than the aforementioned Class I cleanliness, the airborne microorganism concentration is below 200 CFU/m³ (6 CFU/ft³), and the lowest possible bacterial concentration is set as the target.
(2) In the preparation room (for surgical instruments), the actual methods of handling sterile instruments and dressings vary widely. When opening the packaging of sterilized materials, it is necessary to carry out the work under the laminar clean air delivered from a supply air outlet equipped with a high-performance filter. This concept is also shown in Table 2.1-1.
(3) In general operating rooms, there have in recent years also been demands to expand the clean area around the operating table and maintain a higher degree of cleanliness. For this purpose, the supply air volume is increased (total air change rate of 30–50 changes/h).
(4) For the sterile preparation room in Table 2.1-1, products such as large-volume infusions and injections may be placed in a clean bench installed in a Class IV cleanliness dispensing room. When the preparation is carried out in the clean bench, a cleanliness equivalent to Class II can be obtained.
(5) When treating patients with infectious diseases (such as pulmonary tuberculosis) in the operating room, care must be taken to provide Class V cleanliness together with negative pressure, and the exhaust side must be treated. Table 2.1-1 Cleanliness Classes and Ventilation Conditions
| Cleanliness class | Name | Summary | Applicable rooms (representative examples) | Minimum air change rate/(times/h) (fresh air: total air) | Terminal filter efficiency¹⁾ | Reference index (average microbial count during normal operation) |
|---|---|---|---|---|---|---|
| A Medical area | ||||||
| Ⅰ | Highly clean area | Highly clean area requiring a laminar flow system. Positive pressure maintained with respect to each surrounding room | Biological clean operating room Biological clean ward | 5²⁾:2¹⁾ 5 | DOP counting method 99.97% | 10CFU/m³ or below¹⁰⁾ |
| Ⅱ | Clean area | Cleanliness required is lower than Class Ⅰ; a laminar flow system is not necessarily required. Positive pressure maintained | General operating room Surgical instrument room Clean corridor Sterile storage room of the materials department Sterile preparation room Wound irradiation room⁴⁾ Scrub sink area | 5²⁾:20 5:20 5:15 5:15 5:20 5:15 5:15 | (DOP counting method 95% or above) Colorimetric method 80% or above | 200CFU/m³ or below |
| Ⅲ | Quasi-clean area | Cleanliness required is slightly lower than Class Ⅱ but higher than general areas. Positive pressure maintained with respect to Class Ⅳ and lower areas | Areas around the surgical department (recovery room, etc.) NICU, ICU, CCU Premature infant room Special examination and treatment room⁵⁾ Delivery room, breast-feeding room | 3:10 3:10 3:10 3:10 3:10 | (Colorimetric method 90% or above) Colorimetric method 80% or above | 200CFU/m³ or below |
| Ⅳ | General clean area | General area where patients in the room are in a wound-free state. Approximately zero pressure | General ward, reception room, consultation room Waiting room Main entrance hall General-area rooms of the materials and examination departments X-ray radiography room Endoscopy room Hemodialysis room Normal newborn room Physical therapy room Dispensing room | 2⁶⁾:6 2:6 2:8 3:8 2:6 3:10 2:8 3:10 3:10 3:8 3:10 | Colorimetric method 60% or above | 200~500CFU/m³ or below |
| Ⅴ | Contamination control area | Rooms handling harmful substances, such as those generating odors; negative pressure must be maintained to prevent room air from leaking outdoors | Rooms in the RI control area Bacteriological examination room Infectious disease ward examination room Autopsy room Morgue ………… Patient toilet Dressing room Soiled waste processing room | All exhaust: 12⁷⁾ All exhaust: 12 All exhaust: 10 All exhaust: 15⁷⁾ All exhaust: 10 ………… —:15 —:5 —:15 | Colorimetric method 60% or above …………… — | — |
| B General area | ||||||
| Ⅵ | General area | Air conditioning of ordinary rooms and workrooms not specific to hospitals | Office Medical department Meeting room Lecture room, cafeteria | 2:6 2:6 2:6 2:8 | (Colorimetric method 60% or above) | — |
| Ⅶ | Contamination diffusion prevention area | For rooms generating large amounts of odors, dust, etc., negative pressure is maintained to prevent diffusion to the outside | General toilet General garbage processing room | —:10 —:15 | — | — |
1) Values in parentheses in the terminal filter efficiency column are the preferred methods. 2) To exhaust residual anesthetic gas and odors generated when a laser scalpel is used, there are also cases requiring a fresh air volume of 10 times/h or more. 3) Supply air velocity is controlled at: 0.35m/s for vertical laminar flow and 0.45m/s for horizontal laminar flow. 4) For the irradiation room, the air supply method and air volume of the operating room are applied to ensure high cleanliness of the surroundings. 5) Special examination rooms include the cardiovascular angiography room, cardiac catheterization room, cystoscopy room, etc. 6) When each room is provided with its own toilet, the fresh air volume may also be determined by the required exhaust volume. 7) The ventilation volume actually required is determined by the type and amount of radioactive substances handled, the handling method, and the effective dilution volume. 8) Wards and consultation rooms for patients who pose a risk of airborne infection. 9) In the case of infectious diseases, take 20 times/h or more. 10) CFU is the abbreviation for Colony Forming Unit. It corresponds to the number of microbial colonies contained in a unit volume of air. In addition, for kitchens, the Design and Management Guidelines for Hospital Dietary Systems (June 1994) issued by this Association shall be followed.
2.1.4 Class III Cleanliness Level (Quasi-Clean Area)
In quasi-clean areas, together with the use of filters of medium performance or higher (biased toward the high-performance side), positive pressure must be maintained relative to areas of Class IV cleanliness or lower, and appropriate air pressure and airflow direction must be maintained.
【Commentary】
(1) Quasi-clean areas required for ICUs, premature infant rooms, etc., are rooms with a cleanliness level slightly lower than that of the aforementioned clean areas; the concentration of microorganisms in the air shall be kept at 200 CFU/m³ (6 CFU/ft³) or less as the standard.
(2) There are strong opinions that delivery rooms require a cleanliness level higher than Class IV; accordingly, they should be treated as equivalent to premature infant rooms.
2.1.5 Class IV Cleanliness (General Clean Area)
In general clean areas, it is desirable to use filters of medium performance or higher; as a measure against infection, an appropriate airflow should be arranged, and the positional relationship between supply air outlets and return air outlets, etc., must be examined.
【Commentary】
(1) For general wards, examination rooms, and waiting rooms that meet the requirements of general clean areas, the target is to keep the concentration of microorganisms in the air at 200–500 CFU/m³ (6–15 CFU/ft³).
(2) In general areas of hospitals, it is necessary to pay attention to the distribution of indoor airflow during air-conditioning operation. Supply air outlets and return air outlets should be arranged so as to prevent contaminated air from coming into contact with patients as much as possible.
(3) In artificial dialysis rooms, the required cleanliness differs depending on the medical content, and attention should be paid to this; see Section 7.11.1 (omitted).
In addition, as a countermeasure against odors, there are cases where a larger amount of outdoor fresh air is adopted.
2.1.6 Class V Cleanliness (Contamination Control Area)
In contamination control areas, the room must be maintained at a negative pressure relative to the surrounding areas to prevent contaminated indoor air from leaking outdoors.
【Commentary】
(1) In contamination control areas and in bacteriological examination rooms, autopsy rooms, etc., the room must be maintained at a negative pressure to prevent indoor air from leaking outdoors. Furthermore, the air cleanliness should be maintained at Class IV or better.
(2) In isolation rooms for infectious diseases transmitted through the air, etc., it is necessary to simultaneously maintain a negative-pressure anteroom of high cleanliness; the air cleanliness of the anteroom should be raised by one further class, and it must be taken into consideration that the corridor-side window and the patient-room-side window must not be opened at the same time. In cases requiring even stricter control, the anteroom may also be arranged in two stages, i.e., regarded as two anterooms.
(3) In mourning rooms where no incense is offered or lit, a full exhaust system is unnecessary.
(4) To create a locally negative-pressure space within the room and to discharge contaminated air rapidly without allowing it to spread, a safety cabinet should be used. Local exhaust methods, such as direct exhaust from the autopsy table, are effective. Particularly when performing autopsies of infectious cases, a supply air method with vertical laminar flow and a large air volume is desirable.
(5) On the exhaust-air side of the room, appropriate filters must be installed to remove contaminants.
(6) Outside the hours during which the room is in use, the corresponding exhaust fan must be kept running continuously to maintain the negative pressure. In addition, it is desirable to provide exhaust systems that operate at a small air volume at night for shared toilets of wards, etc.
2.1.7 Class V Cleanliness (General Zone, General Area)
General areas in general zones must comply with the Law Concerning the Securing of a Sanitary Environment in Buildings (Building Management Law).
【Commentary】
In terms of air-conditioning zoning, these are ordinary rooms not specific to hospitals, and rooms related to special cleanliness levels are not provided, but they must comply Follow the relevant provisions of the Building Management Law (see Table 2.1-3b).
Table 2.1-3b Standards for Air Conditioning Equipment under the Centralized Management Method (Numerical Values from the Building Management Law)
| Airborne dust concentration | 0.15mg/m³ or less |
| Carbon monoxide content | 10ppm |
| Carbon dioxide content | 1000ppm or less |
| Temperature | (1)17～28℃ (2)When the room temperature is lower than the outside air temperature, the difference shall not be excessive¹) |
| Relative humidity | 40%～70% |
| Airflow velocity | 0.5m/s or less |
1) According to the notification of the Ministry of Construction (Showa 45), approximately 7℃ or less.
2.1.8 Class VI Cleanliness (General Areas, Contamination Spread Prevention Areas)
In contamination spread prevention areas, forced exhaust equipment shall be installed, and care must be taken to prevent contaminated indoor air from leaking to the outside.
[Commentary]
To prevent harmful substances from leaking outdoors from rooms that generate large amounts of dust, moisture, odors, etc., the indoor air must be kept at a negative pressure. The indoor cleanliness should preferably be lower than that of general areas (Class IV).
2.2 Air Quality Conditions
2.2.1 Maintenance of Air Quality Conditions
The air conditioning equipment in hospitals must maintain the necessary healthy, safe, and comfortable air quality conditions for inpatients.
[Commentary]
(1) In hospitals, appropriate air conditioning refers to the effective prevention and management of the following conditions: patients with respiratory diseases, patients with chronic hepatitis, patients receiving oxygen therapy, patients who have undergone tracheostomy, patients with thyrotoxicosis, patients with heart disease, patients with head trauma, patients who have undergone brain surgery, patients with barbiturate poisoning, patients with rheumatoid arthritis, etc.
(2) On the other hand, various harmful airborne pollutants specific to each space are constantly present throughout the hospital, and the air conditioning equipment thus becomes a source of transport and dissemination of these pollutants.
(3) Among the harmful airborne pollutants commonly present in hospitals are microorganisms and chemical substances.
(4) In addition to causing infections, microorganisms are also causative agents of allergic reactions and sources of odors.
(5) Harmful chemical substances include: air pollutants infiltrating from outdoors; various chemical substances emitted from office equipment (copiers, printers, etc.), consumer products (insecticides, detergents, liquid soaps, shampoos, polishes, deodorants, etc.), furniture, and building materials; as well as organic solvents, mercury, lead, disinfectants, anesthetic gases, etc. used in tests. These substances are not only harmful to health but also become sources of odor generation.
(6) From the viewpoint of air cleaning, these harmful airborne pollutants are classified into particulate matter (solids and liquids) and vapors and gases. Among these pollutants, particulate matter of particular note includes tobacco smoke (solids and liquids), asbestos fibers, pollen, and spores (triggers of allergic reactions), while vapors and gases requiring particular attention include ammonia, carbon monoxide, carbon dioxide, nitrogen oxides, formaldehyde, ethylene oxide, volatile organic compounds, anesthetic gases, etc.
(7) In addition, not included in air quality issues are radiation, X-rays, ionizing radiation, light, infrared rays, ultraviolet rays, Problems of harmful energy generated by ultrasound, magnetic field lines, heat (high temperature, low temperature), noise, vibration, etc.
(8) The detection of harmful pollutants shall for the time being be carried out in each individual space and considered separately. Ultimately, the hospital shall be considered as a whole.
2.2.2 Prevention of Cross-Contamination
Cross-contamination from spaces with relatively low air cleanliness to spaces with high air cleanliness must be prevented.
[Commentary]
(1) To prevent harmful airborne pollutants from leaking from one space into other spaces, or leaking in the reverse direction, it is necessary to consider maintaining the relative indoor pressure (positive or negative pressure) of adjacent spaces so as to prevent leakage.
(2) In general, the pressure difference between indoor and outdoor air can only be maintained when openings such as room doors are closed, and it is achieved by setting the difference between the indoor supply air volume and the exhaust air volume.
2.2.3 Supply Air Volume for Satisfying Indoor Air Quality Conditions
To satisfy the air quality conditions of each room, the outdoor air volume and total air volume of each room should preferably be maintained at the values shown in Table 2.1-1.
[Commentary]
(1) The supply air volume (total air volume) of a space is generally the sum of the minimum outdoor air volume and the recirculated air volume (return air volume). This supply air volume is obtained from thermal load calculations. To satisfy air quality requirements, the calculated values must be compared, and the larger value shall be adopted as the supply air volume.
(2) In other words, there are two methods for determining the supply air volume based on air quality. The first is the method of obtaining the supply air volume from the air change rate (ventilation rate) specific to the space. The air change rate is derived from extensive practical experience, and under the specified conditions it is desirable to use this value. However, since the ceiling height, conditions of use, etc. of rooms are stipulated by the standard, attention must be paid in cases where the conditions differ.
(3) The second method is applied when no air change rate is given: for each pollutant, the concentration actually generated in the space is estimated from the allowable concentration value, and the supply air volume is obtained by calculation. In this case, it is necessary not only to set the generated concentration, but also to determine the ventilation efficiency, safety factors, air age (the residence time of pollutants generated in a space within that space), etc. In addition, this is closely related to the airflow distribution and the control method of the flow direction. The factors to be considered are those described in (4) to (9) below.
(4) First, the minimum outdoor air volume is calculated from the maximum number of people simultaneously occupying a space and the outdoor air volume required per person; this is used to check whether the supply air volume determined by the minimum outdoor air volume can dilute the pollutants generated in that space to the required allowable level.
(5) When dilution is not possible, the purification method for the supply air shall be considered, and particulate matter shall be removed by means of air filters.
(6) For vapors and gases, gas removal devices such as adsorption devices shall be examined.
(7) When no economical and effective removal device is available, consideration shall be given to increasing the exhaust air volume of the space and balancing it with the outdoor air volume so as to satisfy the dilution of pollutants.
(8) Operating rooms also contain microorganisms; appropriate air filters are used to remove particulate matter through air recirculation. However, filters are ineffective against anesthetic gases. To dilute these anesthetic gases, the outdoor air volume of the operating room is usually increased, i.e., made greater than the outdoor air volume per person.
(9) Furthermore, in certain wards the required outdoor air volume must be greater than the outdoor air volume per person. This is because patients require a larger outdoor air volume than healthy persons, and in addition there are also the effects of odors and other vapor and gaseous contamination.
(10) In spaces handling unsealed radioactive materials, full outdoor air and full exhaust shall be used, and a device for removing radioactive substances must be installed on the exhaust side (Radiation Hazard Prevention Act).
(11) In spaces handling highly infectious pathogenic bacteria, full outdoor air and full exhaust shall be used, and a device for removing pathogenic bacteria must be installed on the exhaust side.
(12) For flammable substances (diethyl ether, acetaldehyde, propylene oxide, carbon dioxide, n-hexane, benzene, ethylene oxide, methyl ethyl ketone, methanol, xylene, etc.) and combustible gases (acetylene, hydrogen, propane, ammonia, methane, etc.), their concentrations must be controlled below the explosion limit conc degrees or below. When there is a risk of explosion, explosion-proof measures must be taken (Industrial Safety and Health Act).
2.3 Temperature and Humidity Conditions
2.3.1 Basic Conditions
The temperature and humidity of each room shall follow Table 2.3-1 as the standard, but when it is medically necessary, they must be determined through consultation with the physician in charge, etc.
【Commentary】
(1) Table 2.3-1 lists the temperature and humidity conditions of representative rooms in a hospital. For the specific conditions of other rooms, refer to Chapter 7 (omitted). Furthermore, as design conditions and guidance for selecting equipment capacity and duct sizes, the values in this table are required to be strictly satisfied in actual application, regardless of the nature of the situation. From the viewpoint of energy conservation, within the allowable range, it is desirable to reduce operating energy consumption wherever conditions permit.
In hospital wards in extremely cold regions, owing to living habits, there is a tendency for temperatures to become excessively high during heating; in such cases, attention must also be paid to the adverse effects of the resulting lowering of humidity.
(2) In medical activities, it is also necessary to consider special temperature conditions. For example, surgery performed in a low-temperature environment (cardiac surgery, etc.) and 24-hour air conditioning intended to protect against temperature changes caused by medical equipment (radiographic imaging devices, MRJ, etc.) must each satisfy their respective conditions.
(3) Attention must also be paid to the indoor temperature distribution; indoors, the effects of cold radiation caused by exterior walls and window glass, as well as the heat load from solar radiation, are significant. In addition, the installation location of the thermostat that senses room temperature should mainly be selected at an appropriate location representative of the temperature.
2.3.2 Factors of the Thermal Environment and Comfort Indices
Besides temperature and humidity, the operative temperature is also greatly affected by radiation and airflow; therefore, these must be carefully examined.
【Commentary】
(1) As factors affecting the thermal environment, in addition to temperature and humidity, there are also radiation and convection from the building envelope, as well as the human metabolic rate and clothing insulation; these are called the six factors of the thermal environment. Ordinary air conditioning control, etc., is the regulation of temperature and humidity; when necessary, attention should be paid to the mean radiant temperature (MRT) of the envelope surfaces and to the operative temperature affected by drafts caused by the air-conditioning supply airflow.
(2) Figure 2.3-1 (omitted) concerns the influence of radiant heat. With respect to the operative temperature, it has almost the same degree of influence as room temperature, as demonstrated by experimental reports.
【Example】 When wearing 0.5 clo of clothing (note: 1 clo = 0.15 m²·℃/W), the same operative temperature is obtained when the room temperature rises from 26℃ to 30℃ while the mean radiant temperature falls from 26℃ to 21℃. Table 2.3-1 Temperature and Humidity Conditions for Main Rooms
| Department | Room Name | Summer Dry-Bulb Temperature DB/℃ | Summer Relative Humidity RH/% | Winter Dry-Bulb Temperature DB/℃ | Winter Relative Humidity RH/% | Remarks |
|---|---|---|---|---|---|---|
| Ward Department | Ward | 24～26～27 | 50～60 | 22～23～24 | 40～50 | Pay attention to the influence of cold radiation from windows and sunlight |
| Ward Department | Nurses' Station | 25～26～27 | 50～60 | 20～22 | 40～50 | Pay attention to the influence of cold radiation from windows and sunlight |
| Ward Department | Reception Room | 26～27 | 50～60 | 21～22 | 40～50 | Pay attention to the influence of cold radiation from windows and sunlight |
| Outpatient Department | Consultation Room | 26～27 | 50～60 | 22～24 | 40～50 | Temperature higher than the waiting room |
| Outpatient Department | Waiting Room | 26～27 | 50～60 | 21～22 | 40～50 | Temperature higher than the waiting room |
| Outpatient Department | Outpatient Pharmacy | 25～26 | 50～55 | 20～22 | 40～50 | Temperature higher than the waiting room |
| Outpatient Department | Emergency Operating Room | 23～24～26 | 50～55～60 | 23～26 | 45～55～60 | Temperature higher than the waiting room |
| Central Diagnosis and Treatment Department | Operating Room | 22～24～26 | 50～60 | 22～26 | 45～55～60 | Higher temperature settings are also required |
| Central Diagnosis and Treatment Department | Recovery Room | 24～26 | 50～55～60 | 23～25 | 45～50～55 | Higher temperature settings are also required |
| Central Diagnosis and Treatment Department | ICU | 24～26 | 50～55～60 | 23～25 | 45～50～55 | Higher temperature settings are also required |
| Central Diagnosis and Treatment Department | Delivery Room | 24～25～26 | 50～55～60 | 23～25 | 45～50～55 | Higher temperature settings are also required |
| Central Diagnosis and Treatment Department | Newborn Room, Premature Infant Room | 26～27 | 50～60 | 25～27 | 45～55～60 | Higher temperature settings are also required |
| Central Diagnosis and Treatment Department | General Examination Room | 25～26～27 | 50～60 | 20～22 | 40～50 | Higher temperature settings are also required |
| Central Diagnosis and Treatment Department | X-ray Radiography Room | 26～27 | 50～60 | 24～25 | 40～50 | Higher temperature settings are also required |
| Central Diagnosis and Treatment Department | Control Room | 25～26 | 50～60 | 20～22 | 40～50 | Higher temperature settings are also required |
| Central Diagnosis and Treatment Department | Hydrotherapy Room | 26～27 | 50～65 | 26～28 | 50～65 | Higher temperature settings are also required |
| Central Diagnosis and Treatment Department | Autopsy Room | 24～26 | 45～50～55 | 20～22 | 40～50 | Higher temperature settings are also required |
| Supply Department | Kitchen | According to the design and management guidelines for hospital dietary service systems | Countermeasures against equipment heat generation; necessary radiant heating is desirable | |||
| Supply Department | Laundry Room (around work area) | 30 or below | 70 or below | 15 or above | 40 or above | Countermeasures against equipment heat generation; necessary radiant heating is desirable |
| Supply Department | Materials Department rooms | 25～26～27 | 50～60 | 20～22 | 40～50～55 | Countermeasures against equipment heat generation; necessary radiant heating is desirable |
| Administration Department | Administrative Office | 26～27 | 50～60 | 20～22 | 40～50 | When used in combination with air conditioning, pay attention to the influence of radiant heat |
| Administration Department | Doctors' Office | 26～27 | 50～60 | 20～22 | 40～50 | When used in combination with air conditioning, pay attention to the influence of radiant heat |
| Administration Department | Conference Room | 26～27 | 50～60 | 20～22 | 40～50 | When used in combination with air conditioning, pay attention to the influence of radiant heat |
| Administration Department | Central Monitoring Room | 25～27 | 50～60 | 21～22 | 45～50 | When used in combination with air conditioning, pay attention to the influence of radiant heat |
Notes:
1) The underlined values in the table are the standard design condition values for air conditioner design (the heat load is determined by a pair of temperature and humidity parameters. For example, DB24℃ and RH55% are roughly equivalent to DB25℃ and RH50%).
2) When rooms are affected by summer solar radiation and radiation from high-temperature equipment, as well as by cold radiation in winter, it is necessary to change the design room temperature. Conversely, in cases where radiant effects are obtained from floor heating, the room temperature can also be lowered by 1～2℃.
3) Regarding outdoor design weather conditions, for 24h air conditioning or air conditioning systems for important rooms and general air conditioning systems, the settings shall be changed if the exceedance probability is exceeded. The so-called exceedance probability refers to the percentage (%) representing, in the statistics of outdoor air temperature occurrence frequency (counted in chronological order), the proportion that exceeds a certain set value. For example: [set the exceedance probability of the outdoor air temperature for heating design over the 4 winter months to 2.5%]. For important rooms or rooms subject to 24-hour operation, the design conditions are strict, and an exceedance probability of 1% is adopted.
4) In operating rooms, LDR-type wards (see Section 7.7.1 (omitted)), biological clean wards, etc., it is required to change the set room temperature with the passage of time according to indoor usage conditions, and the temperature of these rooms can be set individually and separately.
5) For emergency operating rooms and the like that are not limited to ordinary use, attention must be paid to the capacity of the air conditioning equipment so that the set temperature and humidity conditions can be reached rapidly.
6) In places such as corridors and toilets where frequent temperature adjustment is not performed, as well as in spaces within the patients' living areas, appropriate auxiliary heating devices should be installed to protect occupants from extreme thermal shock, and it is desirable to implement intermittent operation at night to maintain the temperature.
7) In X-ray radiography operation rooms, central examination rooms, etc., the heating load is generally small while the indoor heat generation is large; therefore, even in winter, systems capable of cooling are often required.
2.4 Noise and Vibration Conditions
2.4.1 Basic Policy
Noise levels shall conform to the standards listed in Table 2.4-1. Machinery, piping, and duct systems are sources of noise and vibration. Appropriate sound attenuation and vibration isolation measures are required, and every effort must be made to maintain a safe and comfortable living environment for patients and a good working environment for medical staff, so that they do not become an obstacle to medical activities.
[Commentary]
(1) In medical and welfare facilities, greater attention must be paid to noise and vibration than in ordinary buildings. Under conditions of prolonged quiet, noise and vibration are easily perceived—this is particularly true of patients who are physically and mentally weakened and anxious. In addition, the noise and vibration of air-conditioning equipment can also interfere with the various examinations and treatments involved in medical activities (hearing tests, analysis with an electron microscope, surgery under a microscope, etc.).
(2) Indoor noise and vibration levels. In addition to installing sound attenuation and vibration isolation devices for air-conditioning equipment, the generation of noise and vibration around the building should be brought well under control, and attention should also be paid to the building's structure and its sound insulation and sound absorption performance.
(3) When vibration-generating air-conditioning units are located on the floor above a microsurgery operating room, vibration isolation measures such as thickening the floor slab should be considered in the building structure, and at the same time complete vibration isolation devices should be incorporated so that vibration is not transmitted from the vibrating source.
Table 2.4-1 Standard Values of Noise Levels for Major Rooms
| Room Name | Noise level NC, values in [] are dB(A) |
|---|---|
| Hearing test rooms, heart sound examination rooms 1), etc. | 15～25 [25] |
| Single-patient wards, recovery rooms, EEG examination rooms, director's office, chief nurse's office, etc. | 25～30 [35～40] |
| General wards, ICU, premature infant rooms, newborn nurseries, general operating rooms, delivery rooms, libraries, conference rooms | 30～35 [40～45] |
| Consultation rooms, general examination rooms, radiotherapy rooms, radiology department and various other imaging rooms, autopsy rooms, reception rooms, nurses' stations, etc. | 30～40 [40～45] |
| Waiting areas, physical therapy, hydrotherapy rooms, central supply station, pharmacy, main entrance lobby, corridors, offices, dining halls, bio-clean operating rooms, bio-clean wards, etc. | 35～40 [45～50] |
1) In these rooms, aim for the lower values within the range as much as possible. In addition, for wards and the like, it is desirable to keep the level 5 dB(A) lower at night.
2.5 Prevention of Nosocomial Infectious Diseases
In design and management, the provisions of this guideline must be followed in order to prevent nosocomial infectious diseases.
[Commentary]
(1) Definition of nosocomial infectious diseases and other causative microorganisms
Nosocomial infectious diseases are those in which the cause of illness after admission is unrelated to the patient's original disease, but rather results from a new infection contracted within the hospital. Therefore, if a patient falls ill after discharge as a result of an infection transmitted within the hospital, it should also be classified as a nosocomial infectious disease. Moreover, not only patients but also visitors and healthcare workers—all diseases caused by microbial infection acquired within the hospital—are classified as nosocomial infectious diseases.
In recent years, the microorganisms mainly targeted as causes of hospital-acquired infection have been methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, fungi, hepatitis B virus, hepatitis C virus, the AIDS virus (HIV), and tubercle bacilli. In addition, influenza virus, subviruses, lymph gland virus, and the neurotropic Legionella group such as the pathogenic bacteria of Legionnaires' disease, which were originally regarded as being transmitted through the respiratory tract, are still considered to pose a risk of hospital-acquired infection.
HBV, HCV, and HIV are blood-related viruses that cause disease by directly invading the patient's bloodstream; they are not transmitted via the air. (2) The Importance of Air Conditioning Equipment in Preventing Hospital Infectious Diseases
Air conditioning equipment is of great importance in preventing nosocomial infectious diseases. Among the measures, isolating infectious patients from susceptible patients by means of hospital zoning planning and controlling airflow through air pressure differentials within the clean areas is an important means of preventing airborne infectious diseases.
When the functions of the air conditioning equipment are inappropriate, microorganisms and various allergens (alleigen, antigens that cause allergy) will proliferate and be released within the air conditioning system; if humidity cannot be controlled, adverse effects will be produced on the respiratory system. In addition, as for microorganisms floating in the indoor air, at night when the air conditioning is shut off a chimney effect occurs: air from the lower floors moves up to the upper floors, and infection-related microorganisms from the lower floors can be transmitted to patients on the upper floors, and may also cause allergic reactions [see Section 3-1-1 (omitted)]. Therefore, air conditioning equipment is the most important element for maintaining clean air and a comfortable hospital environment. Important microorganisms related both to air conditioning and to hospital infection are shown in Table 2.5-1.
Table 2.5-1 Main Microorganisms Determined by Transmission Route
| Airborne-transmitted species | Droplet-transmitted species | |
|---|---|---|
| Bacteria | Tubercle bacillus | Diphtheria bacillus, pertussis bacillus, hemolytic streptococcus, meningococcus, type B influenza bacillus, fungal viruses |
| Viruses | Varicella (chickenpox), herpes zoster virus, measles virus | Lymph gland virus, influenza virus, neurovirus, rubella virus |
(3) Relationship between the Main Microorganisms of Nosocomial Infectious Diseases and Air Conditioning Equipment
1) Staphylococcus aureus. Among Staphylococcus aureus there are antibiotic-resistant MRSA bacteria (methieillin-S. MSSA).
As a common resident bacterium of humans, Staphylococcus aureus is frequently isolated from the skin and nasal cavity. Most hospitalized patients carry MRSA, while MRSA as nasal resident bacteria among healthcare workers accounts for about 5%.
These gram-positive cocci can survive for a long time in a dry state, and there is a high possibility that they frequently attach to the bedding of bacteria-carrying patients and to the ward environment. Moreover, with the changing of positions and improper cleaning, the cocci are whirled up into the air and become airborne, then attach to the hair and clothing of staff members, and are thereby transported to other patients' wards.
The main transmission route of MRSS is contact transmission mediated by the fingers.
2) Pseudomonas aeruginosa. Its main habitat within the hospital environment is moist, water-retaining zones, and its main transmission route is contact transmission. It inhabits the patient's intestinal tract and, together with the excreta, causes wound infections, bedsore infections, urinary tract infections, and respiratory tract infections. Once infection occurs, it is difficult to treat with antibacterial drugs.
With regard to Pseudomonas aeruginosa, consideration must be given on the part of the air conditioning equipment: moist locations such as air atomizers used for air conditioning, humidification devices, and condensate water are breeding grounds for the bacteria. Especially inside the ducts during cooling operation, the relative humidity is mostly above 80%, and condensation inevitably promotes the proliferation of Pseudomonas aeruginosa.
The hygienic management of water used within air conditioning equipment must be fully considered; it is not advisable to adopt air atomizers in humidification devices, and steam-atomizing equipment premised on heat sterilization is recommended.
3) Fungi. Fungi are divided into two major categories: yeast-like fungi and filamentous fungi. Representatives of the yeast-like fungi, which are also common resident organisms of the human body, include the genus Candida and the genus Czyntococcus, among others. Filamentous fungi include many kinds, such as genera composed of environment-dependent molds, the genus Coccidioides, and the genus Clado.
There are many fungal spores floating in the air; they not only readily infect patients but are also the cause of mold proliferation inside air conditioning equipment. It should be pointed out that molds proliferating in the drip pans of cooling units, in humidifiers, and inside air ducts may become triggers of allergic rhinitis and of diseases such as asthma and allergic bronchitis. In addition, indoor mold spores can also cause pneumonia.
4) Tubercle bacillus. The tubercle bacillus is particularly resistant to drying and is an important microorganism of air contamination, causing tuberculosis of the lungs and of numerous organs. Pulmonary tuberculosis once declined in our country, but in recent years it has again appeared on a large scale. This is due to AIDS patients with incomplete immunity caused by infection with multidrug-resistant tubercle bacilli from patients, which can also easily occur in general hospitals.
For the examination and treatment of tuberculosis patients, appropriate air-conditioning equipment is indispensable. It is recommended to place the patient on the exhaust side of the airflow, and to filter the air that has been in contact with the patient through high-performance filters before discharging it outdoors.
In the air-conditioning installation, zoning with independent systems centered on patient isolation should be implemented; the air conditioning of wards accommodating bacilli-shedding patients should, as far as possible, operate under negative pressure, and care must be taken to constantly supply patients with clean air.
5) Varicella-zoster virus. Clinically, this same virus causes two different diseases, varicella and herpes zoster.
Varicella (chickenpox) is a viral infectious disease of children, transmitted through the air; it invades the body via the respiratory tract, and after an incubation period of about two weeks eruptions appear; over the following days the eruptions turn into vesicles, then form crusts and heal. Because its infectivity is strongest at the early stage of onset, hospitals must take care that infants and young children do not come close to affected children.
Herpes zoster results from primary infection acquired in childhood; the virus remains latent in the dorsal root ganglia of the spinal cord and is reactivated in adulthood, forming erythema and vesicles along the areas of nerve distribution, accompanied by severe neuralgic pain. The virus is present in the vesicle fluid, and viral antibodies can be demonstrated in exfoliated cells.
6) Legionella. Legionella is a Gram-negative bacillus comprising about 40 species. Most cases of pneumonia are caused by Legionella. It is widely distributed in soil and water in nature and cannot be completely eliminated from the hospital environment.
In water that is rich in organic matter and at a temperature of 20–50℃, it is capable of multiplying. In hospitals, almost all locations—hot water tanks, hot-water supply piping facilities, the water supply taps and shower heads in hot water tanks, room humidifiers, emulsion humidifiers, cooling towers for air conditioning, and so on—provide suitable temperature environments for the multiplication of Legionella. Water containing large numbers of the bacteria disperses and spreads as aerosols; therefore attention must be paid to the location of cooling towers, their distance from fresh-air intakes, and the wind direction; moreover, consideration should be given to ensuring that there are no occupied rooms with open windows within the distance over which water droplets can scatter.
Legionella pneumonia is an acute bacterial pneumonia; the bacterium does not grow on ordinary culture media, and BCYE (buffered charcoal yeast extract) medium is required, making diagnosis difficult. In addition, it is unresponsive to antibiotics, rapidly progresses to a severe stage, and is often difficult to treat; the mortality rate of infections acquired indoors is about 20%, while that of hospital-acquired infections is as high as about 50%.
7) Measles virus
Among children's exanthematous diseases, the most common is the disease called "measles." Its cause is a virus; after an incubation period of about 10 days, cold-like symptoms appear, accompanied by Koplik's spots on the buccal mucosa and fever—symptoms characteristic of a systemic eruption. Infectivity is highest just before and after the eruption appears; the virus is dispersed into the air, invades the respiratory mucosa, and causes airborne infection.
7.6 Surgical Department
7.6.1 Separation of Clean and Contaminated Zones in the Surgical Department
Within the surgical department, a clear zoning of clean and contaminated areas must be established within the scope covered by air conditioning, and it is desirable that, during management and operation, the clean flow lines and the contaminated flow lines do not cross.
[Commentary]
The basic layouts in surgical department planning are roughly classified as follows.
(1) Central hall type. This type was mostly used in China in the past. The flow lines of people (patients, medical staff), clean supplies (surgical instruments, dressings, etc.), and used supplies are all concentrated in the central hall, and there is no clear separation between clean and contaminated circulation routes. However, if used supplies and other items are packaged before being carried out, the air conditioning of this type is still relatively easy to control.
(2) Corridor supply type. This type merely separates the clean-supply flow line of the central hall type in (1), using the peripheral corridor as a single supply route dedicated to clean supplies; it is an improved type in which clean and contaminated flow lines are clearly distinguished. The indoor air reaches a flow balance under the action of positive and negative pressures.
(3) Corridor recovery type. Opposite to the corridor supply type in (2), the dedicated hall for recovering used supplies is changed to a corridor located on the periphery; it is a single mode in which clean and contaminated flow lines are separated. Inside the central supply hall, ensure that clean supplies and surgical The flow line of medical staff. When sterilization and hand-washing facilities are installed in the inner hall, attention must be paid to local exhaust. The direction of indoor air flow must be planned so that air flows from positive pressure toward negative pressure.
(4) Hall supply type. The supply hall dedicated exclusively to clean equipment is arranged at the center; this constitutes a single-route method for clean equipment and is possibly the shortest supply flow line. The design balances the positive and negative air pressures so that the air flows from positive pressure to negative pressure. Surgeons, patients, and used equipment adopt the flow line on the peripheral corridor side and do not enter the supply (clean) hall. The sterile scrub sinks used by surgeons are installed on the peripheral corridor side, maintaining the air cleanliness of the supply hall.
7.6.2 Activity Routes for Air-Conditioning Equipment Maintenance
The air-conditioning machine room inside the department should preferably have a structure that allows maintenance to be performed from outside the clean management area.
[Explanatory Notes]
(1) The entire surgical department must be managed and operated as a clean area. For this reason, when designing the internal air-conditioning machine room, it must be ensured that entry into the interior of the clean department is avoided. The maintenance route should be one that enters from the general area.
(2) The method is to locate the air-conditioning machine room either outside adjacent to the surgical department, or directly above or directly below the surgical department. To secure a maintenance route entering from the general area, the appropriate location of the air-conditioning machine room must be studied.
(3) When renovating existing facilities, circulation units may be installed indoors; in that case, a structure that can maintain cleanliness during maintenance without contaminating the room must be adopted, or the installation method should be considered.
7.6.3 Handling of Activity Routes in Relation to Surrounding Areas
When the activity routes of the surgical department connect with those of other areas, arrangements must be made that do not compromise the internal air cleanliness.
[Explanatory Notes]
When patients, medical staff, equipment, etc. enter the surgical department from other medical areas, in order to maintain the air cleanliness inside the surgical department, the following countermeasures are adopted, namely, the direction of air flow must be from the clean areas of the surgical department to the surrounding general areas:
(1) On the patient entry/exit route, there should be a buffer anteroom and a patient transfer device.
(2) On the medical staff entry/exit route, there should be a changing room serving as an air buffer and a transition from the general area into the quasi-clean area. Moreover, in addition to functioning as an air buffer zone, the changing room also serves to change into gowns, caps, masks, shoes and socks, etc. (air showers or the like are used when necessary to maintain air cleanliness).
(3) At the entrances and exits of elevators or lifts used for transporting equipment, an anteroom should be provided as a buffer zone. Owing to the operation of the lift, the air in the lift shaft flows into the room under pressure; it is desirable to install an exhaust device inside the anteroom. In addition, when equipment moves into and out of areas with different cleanliness levels, bypass rooms or the like should be provided.
(4) When small transporters (such as self-propelled carts) enter at the entrance of the surgical department, measures to block air from flowing into the room must be taken on the travel route, such as installing an air curtain.
7.6.4 Air-Conditioning Environment of General Operating Rooms
General operating rooms must maintain positive pressure relative to the surrounding rooms while attention is paid to indoor air cleanliness and temperature and humidity.
[Explanatory Notes]
(1) To ensure Class II cleanliness around the operating table, supply air outlets equipped with HEPA filters or sub-high-efficiency filters are installed on the ceiling, and the indoor circulating air volume reaches an air change rate of 20 times/h or more.
(2) The return air outlets on the inner walls of the operating room should preferably be arranged uniformly, with the bottom of the outlets higher than the floor level and the top lower than the operating table, so that the airflow supplied from the ceiling covers the operating table. In principle, a device for exhausting residual anesthetic gas should also be installed.
(3) When anesthetic gas is used and there is no device for exhausting residual anesthetic gas, a small fresh air supply will cause the concentration of anesthetic gas in the room to rise; it is recommended that the supplied fresh air volume be 10 air changes/h or more.
(4) The temperature and humidity conditions inside the operating room are set according to Table 7.6 (omitted); the temperature and humidity of each operating room must be able to be adjusted according to the sur variation. The temperature values in the table are those used for general surgery on adults; for pediatric surgery it is approximately 30℃, for organ transplantation approximately 20℃, and so on. In addition, during cardiac, vascular, and similar surgeries, the room temperature must be lowered rapidly (from 25℃ to 19℃ within 30min). To prevent condensation and the sensation of cold among occupants in the room, measures such as increasing the supply air area and reducing the supply air temperature difference must be taken.
(5) General operating rooms must be of a construction that maintains positive pressure relative to surrounding areas such as peripheral corridors. The positive/negative pressure in the room takes the value with the door closed as its standard value; when the door is open, the design pressure of the room is not guaranteed. When maintaining positive pressure, the room pressure must be at least 15Pa (1.5mmH₂O) higher than the surrounding areas. When one air conditioner serves several operating rooms, in order to maintain the positive pressure when an operating room is not in use, it is desirable to adopt a variable air volume operation control method. However, when only one air conditioning unit is installed to serve all operating rooms, the impact in the event of failure is large, so it is desirable to use at least two or more units operating separately.
(6) After the completion of surgery, the following disinfection methods are available for the interior of the operating room.
Disinfectant solution: Wipe the floor, walls, and equipment with disinfectant solution. During the wiping operation, in order to capture airborne particles and shorten the time required for the cleaning work, it is desirable to perform the wiping while the air conditioning is running.
Germicidal lamps: The targets of sterilization are microorganisms attached to the room interior and the surfaces of medical instruments. However, the irradiation dose on airborne microorganisms is small, so no sterilization effect can be expected. The solution is to use air conditioning equipment to target airborne microorganisms and filter them out through HEPA filters. In addition, with ordinary ultraviolet sterilization, no effect can be exerted on areas other than those directly irradiated at close range (such as shadowed areas and undersides of objects).
(7) As for methods of disinfecting the operating room interior with formalin, ozone, etc., since complete sealing is very difficult, problems of leakage from the ducts and doors to the outside may occur, making them difficult to use in practice.
7.6.5 Air Conditioning Environment of Biologically Clean Operating Rooms
The biologically clean operating room is the operating room with the highest air cleanliness class in the hospital. To ensure its Class Ⅰ cleanliness, it is necessary to consider setting the indoor airflow to a laminar flow mode.
[Explanatory Notes]
(1) Biologically clean operating rooms have two modes, horizontal laminar flow and vertical laminar flow, each with the following characteristics.
① Horizontal laminar flow mode (Figure 7.6-5). The patient on the operating table should be kept in the clean area, positioned as close as possible to its downstream side. During surgery, the arrangement of medical staff and equipment on the upstream side should not disturb the laminar flow and should be limited to within the clean area.
② Vertical laminar flow mode (Figure 7.6-6)
It maintains a shadow-free clean area above the patient; compared with horizontal laminar flow, its supply air velocity is steady, and the noise in the operating room is also lower. The shape of the shadowless lamp suspended from the ceiling will affect the flow field and cause disturbance (Figure 7.6-7). Furthermore, the surgeon forms an obstruction above the surgical wound, which tends to generate turbulent flow, making it difficult to maintain cleanliness.
In short, it is necessary to thoroughly study the correlation between the mode adopted and the surgery. For reference materials on the use of aseptic operating rooms, please refer to the Guidelines for the Use of Biologically Clean Operating Rooms (1979) by the Society of Medical Instruments.
(2) To ensure Class Ⅰ cleanliness around the operating table, both modes are equipped with HEPA filters. The standards for supply air velocity are: 0.45m/s for horizontal laminar flow and 0.35m/s for vertical laminar flow. Figure 7.6-5 Horizontal laminar flow system
Figure 7.6-6 Vertical laminar flow system
Figure 7.6-7 Laminar flow variation according to the shape of the shadowless lamp
(3) To more reliably ensure the air cleanliness class, dust generated by the human body must be removed. A full-body exhaust gown covering the entire body may be worn, connected to an exhaust device via an exhaust hose. To improve the effectiveness of air cleanliness at the surgical operating surface, the surgeon should not block the surgical operating surface.
(4) The following methods can be used to improve the air cleanliness of vertical laminar flow:
① Curtain wall method. A curtain wall encloses the area around the ceiling air supply outlet, hanging down to about 2 m above the floor to reduce turbulent flow. To further improve the effect, plastic curtains are extended to near the floor. The surgeon should not block the surgical operating surface, and in this case it also becomes difficult to operate radiological equipment and the like during surgery.
② Surrounding air curtain method. An air curtain is installed to replace the surrounding curtain wall described above. This method tends to generate turbulent flow in some areas, and it also increases the noise inside the operating room.
In short, it is necessary to thoroughly study the correlation between the adopted method and the surgery.
(5) A positive pressure relative to the surrounding areas must be maintained inside the operating room; a differential pressure damper (pressure relief valve) should be installed, and the air volume of excess air above 500m³/h must be adjusted. The air balance here must be properly kept constant, regardless of whether other operating rooms are in use.
(6) The temperature and humidity conditions inside the operating room are the same as those of a general operating room. For the early horizontal laminar flow systems, the maximum allowable noise level at the air velocity is 50dB(A), and it is desirable to reduce it as close to the lower limit as possible.
(7) It is desirable to provide an anteroom at the entrance and exit of the biological clean operating room, serving as a buffer zone for the air conditioning with the surrounding rooms.
(8) Table 7.6-1 shows the differences in infection rates caused by operating room conditions. Table 7.6-1 Differences in Infection Rates Caused by Operating Room Conditions
| Control group No. of operations | Control group No. of infections | Control group Infection rate (A) | UCA system No. of operations | UCA system No. of infections | UCA system Infection rate (B) | (A)/(B) | P level | |
|---|---|---|---|---|---|---|---|---|
| Low bacterial count in air | 2644 | 47 | 2.0 | 1604 | 16 | 1.0 | 2.0 | <0.02(1.1~3.6) |
| Very low bacterial count in air | 2635 | 34 | 1.3 | 2133 | 6 | 0.3 | 4.5 | <0.001(1.8~11) |
| Whole group | 4133 | 63 | 1.5 | 3922 | 23 | 0.6 | 2.6 | <0.011(1.6~4.2) |
Note: 1) Design of ventilation systems for operating rooms. Willian Whgte et al. Translated by Inoue Uichi. Air Cleaning, Vol. 20, No. 3, 1983.
2) UCA (Ultra Clean Air) refers to ultra clean air.
The standard values for airborne bacterial counts established by the Medical Research Council under the UK Department of Health are: the bacterial count at the terminal filter outlet shall be no more than 1 per 1m³. During surgery, the bacterial count in the air near the surgical wound shall be no more than 10 per 1m³, and within the surrounding 3m range, no more than 10 per 1m³.
3) For other experiments, the control group is taken as the reference.
7.6.6 Air Conditioning Environment of Infectious Disease Operating Rooms
In an infectious disease operating room, pathogenic microorganisms must be prevented from escaping out of the room.
[Commentary]
(1) The infectious disease operating room must be a clean area ensuring Class II air cleanliness.
(2) In surgeries for patients with tuberculosis, measles, or chickenpox, the room must be maintained at negative pressure because infection is transmitted via the air. In such cases, it is desirable to provide a clean anteroom to prevent contaminated outdoor air from flowing in. Furthermore, when performing surgery on patients with blood-borne infections such as HIV-positive patients, hepatitis B and C, and syphilis, maintaining positive pressure poses no problem.
(3) When the infectious disease operating room is configured to allow switching between positive and negative pressure, it is desirable to provide, at the entrance/exit, an anteroom with an air pressure higher than that of the operating room as a buffer zone.
(4) For the air conditioning systems of infectious disease operating rooms, it is desirable that each be an independent system.
7.7 Perinatal Department
7.7.1 Air Conditioning Environment of the Perinatal Department
Each room in the perinatal department must maintain the air cleanliness corresponding to its respective function.
[Commentary]
(1) The perinatal department covers the period from 28 weeks of gestation until 7 days after delivery, and is a department that provides comprehensive management of the fetus, newborn, and mother.
(2) The delivery room and related rooms such as the preparation room, shower room, and recovery room must be provided with air conditioning that operates continuously for 24h, and must be of a construction capable of ensuring Class III cleanliness. When surgery is performed in the delivery room due to abnormal delivery or the like, Class II cleanliness around the delivery table must be ensured.
(3) In recent years, LDR-type wards have also been seen in which labor, delivery, and recovery are all accommodated in a single room throughout the entire process from admission to discharge. In coordinating the air conditioning design, sufficient consultation must be held with the building contractor so that the air conditioning functions are not impaired.
(4) The newborn nursery differs from the pediatric ward; its indoor air cleanliness is the same as that of general wards.
(5) The newborn nursery requires an indoor temperature of about 30℃ even in summer; this must be fully discussed with the parties concerned.
7.7.2 Air Conditioning Environment of the Premature Infant Room
For wards accommodating premature infants and others with weak resistance, the air cleanliness corresponding to the function of each room must be maintained. [Commentary]
(1) For the premature infant room and the NICU, Class Ⅲ cleanliness must be ensured.
When patients are housed in premature infant incubators, it is desirable that the room temperature be set at 27℃ in summer and 26℃ in winter, slightly higher than in general wards. The relative humidity should be 50% in both summer and winter.
(2) To maintain the air cleanliness of the various rooms related to the premature infant room, NICU, and newborn nursery (formula preparation room, isolation room, nursing room, shower room, observation room, etc.), partition walls are provided in the building. To facilitate the staff's work and mutual monitoring, these partition walls should preferably be made of transparent materials such as glass. Particular attention should be paid to the temperature and humidity of the glass partitions in winter so that condensation does not form on their surfaces.
7.8 Recovery Department
7.8.1 Air-Conditioning Environment of the Various Therapy Rooms
In the recovery department, since the treatment contents and air-conditioning conditions differ, air-conditioning planning must be carried out to suit the indoor environmental conditions of each respective room.
[Commentary]
(1) In hydrotherapy rooms, patients wear swimsuits, and cold drafts must be prevented, especially in winter. As a countermeasure, it is desirable to install heating equipment with a radiant effect.
(2) When a large amount of water vapor is generated, it is necessary to consult thoroughly with the building-related personnel in order to prevent condensation on the ceiling surface.
In summer, because of the recirculation system and the increase in the air-conditioning load, a thorough study must be made when return air ducts are installed. In addition, since water vapor causes corrosion of the equipment, ducts, and electrical systems, resulting in deterioration, sufficient attention must be paid, and a protection plan should be provided.
(3) As for the return air ducts of hydrotherapy rooms, since the water droplets are assumed to contain Legionella as well, it is desirable that they not enter the recirculation systems of other rooms.
(4) In exercise therapy rooms, in cases where areas are provided for patients to train barefoot, especially in winter, the floor surface temperature of these training areas should preferably be maintained 2～4℃ higher than the room temperature; installing floor heating is one method.
(5) In occupational therapy rooms, in addition to static work such as string and cord work and Japanese paper crafts, there are cases where training in dynamic work such as woodworking, metalworking, and pottery is conducted. During dynamic work, dust is generated, and gases from organic solvents may sometimes also be produced, so appropriate local ventilation must be provided. When electric kilns for pottery and the like are installed, the room temperature rises due to the influence of heat radiation, and the air conditioning must give corresponding consideration to this.
7.12 Supply Department
7.12.1 Air-Conditioning Environment of the Central Supply
Since the work contents differ, the cleanliness classes, temperature and humidity conditions, etc. also differ, and an environment suitable for zoned air conditioning must be maintained.
[Commentary]
(1) In areas where sterilized clean equipment and materials are exposed, Class Ⅱ air cleanliness must be ensured. The air cleanliness of areas where sterilization containers are used, or of areas for unsterilized items, washing, assembly, etc., should be set at Class Ⅳ (see Table 2.1-1 (omitted)).
(2) In washing areas, equipment such as automatic washing machines and assembly-line systems is installed. Due to the use of hot water, steam, etc., and the heat generated by the machinery, the room becomes a high-temperature, high-humidity environment. Air conditioning must be provided, and efforts should be made to maintain a suitable working environment.
(3) When autoclaves are installed in assembly areas and sterilized areas, the surroundings become high in temperature due to the heat from the machine bodies themselves. To prevent the high-temperature gas from diffusing into the room, as shown in Figure 7.12-1, hanging partitions are provided around the autoclaves, and the interior is fully ventilated.
It is desirable to install in-zone cooling equipment, etc., according to the on-site conditions of each area.
(4) Architecturally, with regard to the heat generated by autoclaves, to prevent the heat from being conducted to the floors above and below, insulation material should be applied to the floor slabs; at the same time, to prevent heat from escaping to the outside, it is desirable to install air-separating hanging partitions around the autoclaves, in order to captu collect water vapor and remove heat.
(5) When installing an autoclave, steam piping, water supply piping, and separate exhaust pipes and drain pipes discharging outdoors are required. Since the exhaust and drain pipes carry high temperatures exceeding 100℃, the piping and the pipe runs along the way must be insulated so as not to affect the surroundings (Figure 7.12-2).
(6) There are also autoclaves that do not require piping from a central system and instead come with their own built-in boilers; for these, the handling of the heat generated by the boiler must be considered.
(7) The exhaust gas from ethylene oxide gas sterilizers (EOG sterilizers) is toxic, flammable, and corrosive; the duct materials and fans used are dedicated ones, and must be determined after thorough consultation with the manufacturer.
Figure 7.12-1 Example of Autoclave Installation Figure 7.12-2 Example of piping around an autoclave
Table 7.2 Conditions for each room in the emergency department
| Zone, Room | Cleanliness class | Minimum air volume standard Outdoor air rate, times/h | Minimum air volume standard Total air rate, times/h | Minimum air volume standard Notes | Room pressure (P: positive E: equal N: negative) | Installation of room recirculation units (○: allowed ×: not allowed □: note) | Temperature/humidity conditions Summer Temperature/°C | Temperature/humidity conditions Summer Humidity/% | Temperature/humidity conditions Winter Temperature/°C | Temperature/humidity conditions Winter Humidity/% | Temperature/humidity conditions Notes | Permissible noise level/dB(A) | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Emergency main entrance hall (including vestibule) | IV | 3 | 8 | P | ○ | 27 26 | 50 | 20 22 | 50 | 50 | Recirculation units equipped with HEPA filters may be installed | ||
| Emergency hall | IV | 3 | 8 | E | ○ | 26 | 50 | 22 | 50 | 50 | |||
| External consultation waiting room | VI | 2 | 6 | E | ○ | 50 | 50 | 45 | Pay attention to pressurization and air leakage | ||||
| Examination room | IV | 3 | 8 | E | ○ | 26 | 50 | 24 | 50 | 45 | |||
| Treatment room (emergency operating room) | II | 5 | 20 | 1) | P～E | □ | 24～26 | 50 | 22～24 | 50 | 5) | 45 | |
| Nurse station | IV | 2 | 6 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Explanation room | VI | 2 | 6 | E | ○ | 26 | 50 | 22 | 50 | 40 | |||
| Radiography room | IV | 2 | 6 | E | ○ | 26 | 50 | 24 | 50 | 45 | |||
| Radiography room, control room | IV | 2 | 6 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Emergency and specimen testing room | IV | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 |
Table 7.2 (continued)
| Zone, Room | Cleanliness class | Minimum air volume standard Fresh air changes/h | Minimum air volume standard Total air changes/h | Minimum air volume standard Notes | Indoor pressure (P: positive E: zero N: negative) | Installation of indoor circulation units (○: yes ×: no □: note) | Temperature and humidity conditions Summer Temperature/℃ | Temperature and humidity conditions Summer Humidity/% | Temperature and humidity conditions Winter Temperature/℃ | Temperature and humidity conditions Winter Humidity/% | Notes | Permissible noise level/dB(A) | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Emergency reception, office | Ⅳ | 2 | 6 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Conference room | Ⅵ | 2 | 6 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Physicians' and nurses' lounge | Ⅵ | 2 | 6 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Duty room | Ⅵ | 2 | 6 | E | ○ | 26 | 50 | 22 | 50 | 40 | |||
| Equipment storage room | Ⅵ | 2 | 6 | E | — | — | — | — | — | 45 | |||
| Waste disposal room | Ⅴ | — | 15 | N | — | — | — | — | — | 50 | |||
| Staff and visitor toilets | Ⅵ | — | 15 | N | — | — | — | — | — | 50 | |||
| Emergency ward follows the standard for general wards |
1) When treating patients with infectious diseases, etc., it is desirable that the air-conditioning system be fully exhausted to maintain negative pressure. 2) Individual temperature setting is desirable.
Table 7.4 Conditions of each room in the laboratory department ① [Specimen examination]
| Zone, Room | Cleanliness class | Minimum air volume standard Fresh air changes/h | Minimum air volume standard Total air changes/h | Minimum air volume standard Notes | Indoor pressure (P: positive E: zero N: negative) | Installation of indoor circulation units (○: yes ×: no) | Temperature and humidity conditions Summer Temperature/℃ | Temperature and humidity conditions Summer Humidity/% | Temperature and humidity conditions Winter Temperature/℃ | Temperature and humidity conditions Winter Humidity/% | Notes | Permissible noise level/dB(A) | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| [Specimen examination] | |||||||||||||
| Specimen reception and accumulation room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| General (urine) examination room | Ⅳ | Full exhaust | 10 | N | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Biochemistry examination room | Ⅳ | Full exhaust | 10 | N | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Blood examination room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Serum examination room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Reagent storage room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Refrigerated pharmaceutical storage room | Ⅳ | 2 | 8 | E | ○ | ＜30 | 50 | ＜30 | 50 | 50 | |||
| Data processing room | Ⅳ | 2 | 8 | E | ○ | 25 | 50 | ＜25 | 50 | 50 | |||
| Blood coagulation examination room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Blood sampling room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 23 | 50 | 45 | |||
| Urine sampling room | Ⅴ | Full exhaust | 15 | N | — | 27 | 50 | 22 | 50 | 45 | |||
| Examination equipment room | Ⅵ | 2 | 6 | E | — | — | — | — | — | 45 | |||
| Equipment washing room | Ⅵ | Full exhaust | 6 | N | × | 26 | 50 | 22 | 50 | 50 | |||
| Staff room | Ⅵ | 2 | 6 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Staff toilet | Ⅶ | — | 10 | N | — | — | — | — | — | 50 | |||
| Staff changing room | Ⅵ | 2 | 6 | E | ○ | 27 | 50 | 20 | 50 | 45 | |||
| Bacteriology examination room | Ⅴ | Full exhaust | 12 | N | × | 26 | 50 | 22 | 50 | 45 | N＋ indicates relatively positive pressure compared with bacteriology examination, etc. | ||
| Bacteriology examination room anteroom | Ⅳ | Full exhaust | 8 | N＋ | × | 26 | 50 | 22 | 50 | 45 | |||
| P3 examination room | Ⅴ | Full exhaust | 15 | N | × | 26 | 50 | 22 | 50 | 45 | |||
| Staff changing room | Ⅵ | 2 | 6 | E | ○ | 27 | 50 | 20 | 50 | 45 | |||
| Staff toilet | Ⅶ | — | 10 | N | — | — | — | — | — | 50 | |||
| Staff room | Ⅵ | 2 | 6 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Staff bathroom or shower room | Ⅶ | — | 6 | N | — | — | — | — | — | 50 |
Table 7.4 Conditions of Each Room in the Examination Department ② [Pathological Examination]
| Zone, Room | Cleanliness class | Minimum air volume standard Fresh air volume, times/h | Minimum air volume standard Total air volume, times/h | Notes | Indoor pressure (P: positive E: zero N: negative) | Installation of indoor circulation units (○: yes ×: no) | Temperature and humidity conditions Summer Temperature/℃ | Temperature and humidity conditions Summer Humidity/% | Temperature and humidity conditions Winter Temperature/℃ | Temperature and humidity conditions Winter Humidity/% | Notes | Permissible noise level/dB(A) | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| [Pathological Examination] | |||||||||||||
| Specimen reception and collection room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Section cutting room | Ⅴ | Total exhaust | 12 | N | × | 26 | 50 | 22 | 50 | 45 | |||
| Paraffin embedding room | ⅤⅤ | Total exhaust | 12 | N | × | 26 | 50 | 22 | 50 | 45 | |||
| Microtome room | Ⅴ | Total exhaust | 10 | N | × | 26 | 50 | 22 | 50 | 45 | |||
| Staining room | Ⅴ | Total exhaust | 12 | N | × | 26 | 50 | 22 | 50 | 45 | |||
| Tissue storage room | Total exhaust | 12 | N | × | 26 | 50 | 22 | 50 | 45 | ||||
| Electron microscopy room | Ⅳ | 2 | 7 | E | ○ | 26 | 50 | 22 | 50 | 45 | Pay attention to vibration | ||
| Electron microscopy darkroom | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Electron microscopy preparation room | Ⅳ | 2 | 7 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Chromosome examination room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Cytodiagnosis room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Histodiagnosis room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Waste disposal room | Ⅴ | — | 15 | N | — | — | — | — | — | 50 | |||
| Staff room | Ⅵ | 2 | 6 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Staff changing room | Ⅵ | 2 | 6 | E | ○ | 27 | 50 | 20 | 50 | 45 | |||
| Staff toilet | Ⅶ | — | 10 | N | — | — | — | — | — | 50 | |||
| Autopsy room (general patients) | Ⅴ | Total exhaust | 15 | N | × | 24 | 50 | 22 | 50 | 45 | |||
| Autopsy room (infectious disease patients) | Ⅴ | Total exhaust | 20 | N | × | 24 | 50 | 22 | 50 | 45 | |||
| Preparation anteroom | Ⅳ | Total exhaust | 10 | E | × | 26 | 50 | 22 | 50 | 45 | |||
| Staff changing room | Ⅳ | 2 | 6 | E | ○ | 27 | 50 | 20 | 50 | 45 | |||
| Staff toilet | Ⅴ | — | 10 | N | — | — | — | — | — | 50 | |||
| Staff room | Ⅳ | 2 | 6 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Washing room | Ⅴ | Total exhaust | 10 | N | × | 26 | 50 | 22 | 50 | 50 | |||
| Equipment storage room | Ⅵ | 2 | 6 | E | — | — | — | — | — | 45 | |||
| Staff bathroom or shower room | Ⅶ | — | 6 | N | — | — | — | — | — | 50 | |||
| Specimen preparation room | Ⅴ | Total exhaust | 10 | N | × | 26 | 50 | 22 | 50 | 45 | |||
| Specimen storage room | Ⅴ | Total exhaust | 6 | N | × | ＜30 | 50 | ＜25 | 50 | 45 |
Table 7.4 Conditions of Each Room in the Examination Department ③ [Physiological Function Examination]
| Area, Room | Cleanliness Class | Minimum Air Volume Standard Fresh Air Changes/h | Minimum Air Volume Standard Total Air Changes/h | Notes | Room Pressure (P: Positive Pressure E: Zero Pressure N: Negative Pressure) | Installation of Indoor Circulation Units (○: Yes ×: No) | Temperature and Humidity Conditions Summer Temperature/℃ | Temperature and Humidity Conditions Summer Humidity/% | Temperature and Humidity Conditions Winter Temperature/℃ | Temperature and Humidity Conditions Winter Humidity/% | Temperature and Humidity Conditions Notes | Allowable Noise Level /dB(A) | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| [Physiological Function Examination] | |||||||||||||
| Reception and Office | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | * indicates related to the shielding effect; installation is difficult. | ||
| Cerebrospinal Fluid Examination Room | Ⅳ | 2 | 7 | E | * | 26 | 50 | 23 | 50 | 35 | |||
| Cerebrospinal Fluid Examination Room Control Room | Ⅳ | 2 | 7 | E | ○ | 26 | 50 | 22 | 50 | 40 | |||
| Vascular Electrogram Room | Ⅳ | 2 | 7 | E | * | 26 | 50 | 23 | 50 | 35 | |||
| Vascular Electrogram Room Control Room | Ⅳ | 2 | 7 | E | ○ | 26 | 50 | 22 | 50 | 40 | |||
| Electrocardiogram Room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 23 | 50 | 40 | |||
| Stress Electrocardiogram Room | Ⅳ | 3 | 10 | E | ○ | 25 | 50 | 23 | 50 | 40 | |||
| Auditory Brainstem Response Examination Room | Ⅳ | 2 | 7 | E | ○ | 26 | 50 | 23 | 50 | 40 | |||
| Auditory Brainstem Response Examination Room Control Room | Ⅳ | 2 | 7 | E | ○ | 26 | 50 | 22 | 50 | 40 | |||
| Self-recording Thermometer Room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 23 | 50 | 40 | |||
| Self-recording Thermometer Room Control Room | Ⅳ | 2 | 7 | E | ○ | 26 | 50 | 22 | 50 | 40 | |||
| Waiting Hall | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Equilibrium Function Examination Room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 23 | 50 | 40 | |||
| Respiratory Function Examination Room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 23 | 50 | 40 | |||
| Ultrasound Examination Room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 23 | 50 | 40 | |||
| Film Reading Room | Ⅵ | 2 | 7 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Endoscopy Examination Room (Upper) | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 24 | 50 | 45 | |||
| Endoscopy Examination Room (Lower) | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 24 | 50 | 45 | |||
| Sub-waiting Area | Ⅳ | 3 | 10 | 1) | E | ○ | 26 | 50 | 22 | 50 | 45 | ||
| Changing Room (for Patients) | Ⅳ | 2 | 7 | E | ○ | 27 | 50 | 22 | 50 | 45 | |||
| Endoscopy Treatment Room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 24 | 50 | 45 | |||
| Patient Toilet | Ⅴ | — | 15 | N | — | —26 | — | — | — | 50 | |||
| Washing Room | Ⅴ | Total exhaust | 10 | N | × | 50 | 22 | 50 | 50 | ||||
| Soiled Utility Room | Ⅴ | — | 15 | N | — | — | — | — | — | 50 | |||
| Endoscope Storage Room | Ⅳ | 2 | 7 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Preparation Work Room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Endoscopy TV Room | Ⅳ | 3 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Endoscope Control Room | Ⅳ | 2 | 7 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Equipment Room (Before Use) | Ⅳ | 2 | 7 | E | — | — | — | — | — | 45 | |||
| Equipment Room (After Use) | Ⅳ | 2 | 7 | E | — | — | — | — | — | 45 | |||
| Staff Room | Ⅵ | 2 | 7 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Conference Room | Ⅵ | 2 | 7 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Sleep Room | Ⅳ | 2 | 7 | E | ○ | 26 | 50 | 22 | 50 | 40 | |||
| Hair Washing Room | Ⅴ | 2 | 7 | N | — | 27 | 50 | 22 | 50 | 45 |
1) Total exhaust may also be used to control odors.
Table 7.6 Conditions of Each Room in the Surgical Department①
| Zone, Room | Cleanliness class | Minimum air volume standard Outdoor air changes/h | Minimum air volume standard Total air changes/h | Minimum air volume standard Notes | Indoor pressure (P: positive pressure E: zero pressure N: negative pressure) | Installation of indoor circulation units (○: allowed ×: not allowed □: note) | Temperature and humidity conditions Summer Temperature/℃ | Temperature and humidity conditions Summer Humidity/% | Temperature and humidity conditions Winter Temperature/℃ | Temperature and humidity conditions Winter Humidity/% | Temperature and humidity conditions Notes | Permissible noise level/dB(A) | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Entrance anteroom | Ⅳ | 2 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | □ indicates that installation of circulation unit groups equipped with high-efficiency filters, etc. is permitted | ||
| Transfer area | Ⅲ | 3 | 15 | P | □ | 26 | 50 | 24 | 50 | 45 | |||
| Changing room | Ⅳ | 2 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Shower in changing room | Ⅴ | — | 10 | N | — | — | — | — | — | 50 | |||
| Toilet in changing room | Ⅴ | — | 10 | N | — | — | — | — | — | 50 | |||
| Staff lounge | Ⅳ | 2 | 8 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Control room | Ⅳ | 2 | 8 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Internal corridor (clean zone) | Ⅲ | 3 | 15 | P | □ | 26 | 50 | 22 | 50 | 45 | |||
| General operating room | Ⅱ | 5 | 20 | 1) | P | □ | 24～26 | 50 | 22～26 | 50 | 3) | 45 | P＋ indicates a positive pressure difference relative to the anteroom |
| Sterile scrub room | Ⅲ | 5 | 15 | P | □ | 26 | 50 | 22 | 50 | 45 | |||
| Instrument setup room | Ⅱ | 5 | 20 | P | □ | 24 | 50 | 22 | 50 | 45 | |||
| Aseptic operating room | Ⅰ | 5 | 2) | 1) | P＋ | — | 24～26 | 50 | 22～26 | 50 | 3) | 50 | |
| Aseptic operating room anteroom | Ⅲ | 3 | 15 | P | □ | 26 | 50 | 22 | 50 | 45 | |||
| Infectious disease operating room | Ⅱ | All exhaust | 20 | N | × | 24～26 | 50 | 22～26 | 50 | 3) | 45 | Separate system | |
| Changing room for infectious disease operating room | Ⅳ | 2 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Shower room for infectious disease operating room | Ⅴ | — | 10 | N | — | — | — | — | — | 50 | |||
| Washing room for infectious disease operating room | Ⅴ | — | 10 | N | × | 26 | 50 | 22 | 50 | 50 | |||
| Anteroom for infectious disease operating room | Ⅲ | 3 | 15 | P | □ | 26 | 50 | 22 | 50 | 45 | |||
| Radiography operation room | Ⅲ | 2 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Materials supply hall | Ⅱ | 5 | 20 | P | □ | 24 | 50 | 22 | 50 | 45 | |||
| Materials collection room | Ⅲ | 3 | 15 | E | □ | 26 | 50 | 22 | 50 | 45 | |||
| Materials primary washing room | Ⅲ | All exhaust | 10 | N | — | 26 | 50 | 22 | 50 | 45 | |||
| Materials room, large equipment storage room | Ⅲ | 2 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Anesthesia machine room, ME equipment room | Ⅲ | 2 | 10 | E | ○ | 26 | 50 | 20 | 50 | 45 | |||
| Emergency examination room | Ⅳ | 2 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Recovery room | Ⅲ | 3 | 10 | P | □ | 26 | 50 | 26 | 50 | 40 | |||
| Anesthesia room | Ⅳ | 2 | 8 | E | ○ | 26 | 50 | 22 | 50 | 45 | |||
| Family briefing room | Ⅳ | 2 | 8 | E | ○ | 26 | 50 | 22 | 50 | 40 | |||
| Family lounge area | Ⅳ | 2 | 8 | E | ○ | 26 | 50 | 22 | 50 | 40 |
1) For cases where a larger amount of outdoor air is also required to exhaust anesthetic gases and odors.
2) Determined by the supply air velocity (vertical laminar flow 0.35m/s, horizontal laminar flow 0.45m/s) and the supply air area.
3) For low-temperature surgery and surgery under high-temperature and high-humidity conditions, it is necessary to conform to the medical conditions. Table 7.6 Conditions of the rooms in the surgical department②
| Area, Room | Cleanliness class | Minimum air volume standard: fresh air changes/h | Minimum air volume standard: total air changes/h | Minimum air volume standard: notes | Indoor pressure (P: positive pressure, E: equal pressure, N: negative pressure) | Installation of indoor recirculation units (○: allowed, ×: not allowed, □: see note) | Temperature and humidity conditions, Summer, Temperature/℃ | Temperature and humidity conditions, Summer, Humidity/% | Temperature and humidity conditions, Winter, Temperature/℃ | Temperature and humidity conditions, Winter, Humidity/% | Temperature and humidity conditions, notes | Permissible noise level/dB(A) | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Outpatient operating room | Ⅱ | 5 | 20 | P | □ | 24～26 | 50 | 22～26 | 50 | a) | 45 | □ Recirculation units equipped with high-efficiency filters and similar arrangements may be installed | |
| Anteroom of outpatient operating room | Ⅲ | 3 | 15 | P | □ | 26 | 50 | 22 | 50 | 45 | □ Recirculation units equipped with high-efficiency filters and similar arrangements may be installed | ||
| Changing room of outpatient operating room | Ⅲ | 2 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | □ Recirculation units equipped with high-efficiency filters and similar arrangements may be installed | ||
| Recovery room of outpatient operating room | Ⅲ | 3 | 10 | P | □ | 26 | 50 | 26 | 50 | 40 | □ Recirculation units equipped with high-efficiency filters and similar arrangements may be installed | ||
| Equipment preparation room of outpatient operating room | Ⅲ | 3 | 15 | P | □ | 26 | 50 | 22 | 50 | 45 | □ Recirculation units equipped with high-efficiency filters and similar arrangements may be installed | ||
| Equipment recovery room of outpatient operating room | Ⅲ | 2 | 10 | E | ○ | 26 | 50 | 22 | 50 | 45 | □ Recirculation units equipped with high-efficiency filters and similar arrangements may be installed | ||
| Equipment washing room of outpatient operating room | Ⅲ | All exhaust | 10 | N | — | 26 | 50 | 22 | 50 | 45 | □ Recirculation units equipped with high-efficiency filters and similar arrangements may be installed | ||
| Staff rest room | Ⅵ | 2 | 6 | E | ○ | 26 | 50 | 22 | 50 | 45 |