Standards for air purity in medical institutions are the regulatory basis for the prevention of nosocomial infections. What are "clean rooms"? Requirements for a “clean room” and cleanliness class
In the spread of hospital infection, the airborne route is of greatest importance, due to
than to constantly ensure the cleanliness of the air in the premises of a surgical hospital and operating unit
great attention should be paid.
The main component that pollutes the air in a surgical hospital and operating unit is
is dust of the finest dispersion on which microorganisms are sorbed. Sources of dust
are mainly ordinary and special clothing for patients and staff, bedding,
the entry of soil dust with air currents, etc. Therefore, measures aimed at reducing
contamination of operating room air primarily involves reducing the influence of sources of contamination
to the air.
Persons with septic wounds or any purulent wounds are not allowed to work in the operating room.
Staff must shower before surgery. Although research has shown that in many cases shower
was ineffective. Therefore, many clinics began to practice taking a bath with a solution
antiseptic. At the exit from the sanitary checkpoint, the staff puts on a sterile shirt, pants and shoe covers. After
hand treatment in the preoperative room, wear a sterile gown, gauze bandage and sterile gloves.
The surgeon’s sterile clothing loses its properties after 3-4 hours and is sterilized. Therefore, when
In complex aseptic operations (such as transplantation), it is advisable to change clothes every 4 hours. These
The same requirements apply to the clothing of personnel serving post-transplant patients in the wards.
intensive care.
The gauze bandage is an insufficient barrier to pathogenic microflora, and, as shown
studies, about 25% of postoperative purulent complications are caused by a strain of microflora sown
both from the festering wound and from the oral cavity of the operating surgeon. Barrier functions of gauze
dressings are improved by treating them with petroleum jelly before sterilization.
Patients themselves may be a potential source of contamination, so they should be prepared before
operation accordingly.
Among the measures aimed at ensuring clean air, correct and
constant air exchange in hospital premises, practically eliminating the development of intra-hospital
infections. Along with artificial air exchange, it is necessary to create conditions for aeration and ventilation
premises of the surgical department. Particular preference should be given to aeration, which allows
for many hours and even around the clock in all seasons of the year to carry out natural air exchange,
which is a decisive link in the chain of measures to ensure clean air.
In-wall ventilation ducts contribute to increasing the efficiency of aeration. Effective
the functioning of these channels is especially necessary during winter and transition periods, when the air
premises are largely polluted by microorganisms, dust, carbon dioxide, etc. Research
show that the more air is removed through the exhaust ducts, the more relatively clean air there is in
Bacteriologically, outside air enters through transoms and various leaks. Due to
This requires systematically cleaning the ventilation ducts from dust, cobwebs and other debris.
The efficiency of intra-wall ventilation ducts increases if at their upper end part
(on the roof) install deflectors.
Ventilation must be carried out during wet cleaning of hospital premises (especially
in the morning) and the operating room after work.
In addition to the above measures to ensure air purity and destruction of microorganisms
Disinfection using ultraviolet radiation and, in some cases, chemicals is used. With this
purpose, the indoor air (in the absence of personnel) is irradiated with bactericidal lamps such as DB-15, DB-30 and
more powerful, which are placed taking into account convection air currents. Number of lamps
is set at the rate of 3 W per 1 m 3 of irradiated space. In order to mitigate the negative aspects
action of lamps, instead of direct irradiation of the air, diffuse radiation should be used, i.e.
produce irradiation in the upper zone of the premises with subsequent reflection of radiation from the ceiling, for which
you can use ceiling irradiators, or light luminescent lamps simultaneously with bactericidal ones
lamps.
To reduce the possibility of microflora spreading throughout the operating room
It is advisable to use light bactericidal curtains created in the form of radiation from lamps above the doors, in
open passages, etc. The lamps are mounted in metal spotlight tubes with a narrow slot (0.3-
0.5cm).
Air neutralization with chemicals is carried out in the absence of people. For this purpose
Propylene glycol or lactic acid may be used. Spray propylene glycol
at the rate of 1.0 g per 5 m 3 of air. Lactic acid used for food purposes is used at the rate of 10
mg per 1 m 3 of air.
Aseptic air quality in the premises of a surgical hospital and operating unit can also be achieved
the use of materials that have a bactericidal effect. These substances include derivatives
phenol and trichlorophenol, oxydiphenyl, chloramine, sodium salt of dichloroisocyanuric acid, naphthenylglycine,
cetyloctadecylpyridinium chloride, formaldehyde, copper, silver, tin and many others. They are impregnated
bed and underwear, dressing gowns, dressings. In all cases, the bactericidal properties of materials
lasts from several weeks to a year. Soft fabrics with bactericidal additives retain bactericidal
action for more than 20 days.
It is very effective to apply film or various varnishes and paints to the surface of walls and other objects,
to which bactericidal substances are added. For example, oxydiphenyl mixed with surface active
substances are successfully used to impart a residual bactericidal effect to the surface. Should
Keep in mind that bactericidal materials do not have a harmful effect on the human body.
In addition to bacterial pollution, air pollution in operating rooms is also of great importance.
narcotic gases: ether, fluorotane, etc. Research shows that during the operation in
the air in operating rooms contains 400-1200 mg/m 3 of ether, up to 200 mg/m 3 or more of fluorotane, and up to 0.2% carbon dioxide.
Very intense air pollution with chemicals is an active factor
contributing to the premature onset and development of fatigue among surgeons, as well as the emergence
unfavorable changes in their health.
In order to improve the air environment of operating rooms, in addition to organizing the necessary air exchange
drug gases entering the operating room airspace from
anesthesia machine and exhaled sick air. Activated carbon is used for this. Last
placed in a glass vessel connected to the valve of the anesthesia machine. The air exhaled by a sick person
Group 1 according to GOST 52539-2006
List of operations performed
— transplantation and transplantation of organs and tissues;
— implantation of foreign bodies (prosthetics of hip, knee and other joints, hernia repair with a mesh prosthesis, etc.);
— reconstructive operations on the heart, large vessels, genitourinary system, etc.;
— reconstructive operations using microsurgical techniques;
— combined operations for tumors of various localizations;
— open thoracoabdominal operations;
— neurosurgical operations;
— operations with large surgical fields and/or long duration, requiring prolonged exposure of instruments and materials;
— operations after preoperative chemotherapy and/or radiation therapy for patients with reduced immune status and multiple organ failure;
— operations for combined trauma, etc.
Laminar ceilings are used to protect the patient and sterile instruments from airborne contamination. The device is built into the ventilation supply duct of a medical facility directly into the ceiling above the operating table and provides a continuous supply of purified and sterile unidirectional air flow to the operation area. The device must provide air filtration class H14 99%
. The area of the laminar field is not less than 9m2.
Equipment: Laminar ceilings Tion B Lam-1 with a body height of 400 mm, Tion B Lam-1 H290 with a body height of 290 mm (for low ceilings)
Due to significant air flow, to form a unidirectional flow, it may be advisable to use an operating room ventilation system with partial air recirculation (part of the air is taken from the street by the ventilation system, and part is mixed from the room) provided that it is cleaned and disinfected using filters of at least class H14 with inactivation no less 99%
Equipment:
H11 99%
Equipment:
Air purity standards for highly aseptic operating rooms
5.5. The cross-sectional area of the vertical unidirectional air flow must be at least 9.0 m2.
6.1.
6.3.
|
Group of rooms |
Type of air flow |
Air exchange rate |
Filter class |
|
|
Operating table area |
Not installed |
|||
6.24. The air supplied to cleanliness class A rooms is subjected to cleaning and disinfection by devices that ensure the efficiency of inactivation of microorganisms at the outlet of the installation is at least 99% for class A, as well as filtration efficiency corresponding to high efficiency filters (H11-H14). High purity filters must be replaced at least once every six months, unless otherwise provided in the operating instructions.
For reference:
6.42.
8.9.6.
Group 3 according to GOST 52539-2006
List of operations performed
— endoscopic operations;
— endovascular interventions;
— other therapeutic and diagnostic manipulations with small sizes of the surgical field;
— hemodialysis, plasmapheresis, etc.;
- C-section;
— selection of umbilical cord blood, bone marrow, adipose tissue, etc. for subsequent isolation of stem cells.
H14 and inactivation of microorganisms on filters of at least 95%
. Laminar field area: 3-4m2.
Equipment: Laminar ceiling with a body height of 400mm: Tion B Lam-4 (2600×1800×400mm with a niche for a lamp); for low ceilings with a cabinet height of 290mm: Tion B Lam-4 H290 (3080x1800x290mm with a niche for the lamp).
Due to significant air consumption, to form a unidirectional flow, it may be advisable to use a ventilation system with partial air recirculation (part of the air is taken by the ventilation system from the street, and part is mixed from the room), provided that it is cleaned and disinfected using filters of at least class H14 with inactivation no less 95%
. This allows you to significantly save energy on heating or cooling the supply air by the ventilation system. This method of air exchange can be ensured by installing a laminar ceiling and connecting columns or recirculation modules to it, which ensure the admixture of air from the room.
Equipment: Wall recirculation column -RP for Tion laminar ceilings.
| Disinfection and purification of indoor air |
To reduce contamination and increase the frequency of air exchange, it is recommended to install autonomous disinfectants of air purifiers (recirculators) with a filtration class of at least H11 and inactivation of microorganisms on filters of at least 95%
Equipment: Air disinfectant-purifier Tion A in mobile and wall-mounted versions
Air purity standards for small operating rooms
According to SanPiN 2.1.3.2630-10 clause 6.24 and new SP 118.13330.2012 - Appendix K, the air must be cleaned and disinfected by devices that provide a degree of air filtration not lower than class H14 for areas with unidirectional flow and H13 for areas without unidirectional flow, and also inactivation of microorganisms is at least 95%.
5.4.
In order to ensure the versatility of operating rooms belonging to group 3 and the ability to carry out any operations, it is recommended at the design stage to consider the issue of their execution in accordance with the requirements for premises of group 1.
The use of unidirectional air flow is also advisable when performing operations involving the introduction of foreign bodies into the human parenteral system (for example, catheters). A sterile catheter or other medical device must be unpacked, located and inserted into the human body in an ISO Class 5 area.
5.5. The speed of unidirectional air flow should be in the range from 0.24 to 0.3 m/s. The area with unidirectional air flow should be limited by curtains (shields) along the entire perimeter. Curtains (shields) must be made of transparent materials resistant to disinfectants, usually at least 0.1 m long. The distance from the bottom edge of the curtains (shields) to the floor must be at least 2.1 m.
Due to significant air consumption, to form a unidirectional flow, it is advisable to use a ventilation and air conditioning system with local air recirculation. Local recirculation can use only indoor air, or it can add a certain proportion of outside air.
The separation of the operating room and other rooms is carried out according to one of the principles: pressure difference or displacement air flow. In the latter case, the cleanliness of adjacent rooms can be largely ensured by the flow of air from the operating room. Airlocks may not be provided.
When applying the differential pressure principle, it is recommended to provide continuous (visual or automatic) pressure monitoring.
Rooms for transporting sterile materials (corridors leading to operating rooms) must have a positive pressure drop, including in relation to the operating room. If transportation of sterile materials is carried out in sealed containers (boxes), then the air in the specified rooms (corridors) must be supplied through finishing filters of at least class F9.
6.1.
Requirements for outdoor air flow: at least 100 m3/h per person
and not less than 800 m3/h per anesthesia machine.
6.3. Requirements for air exchange and filter classes
|
Group of rooms |
Room (zone) cleanliness class |
Type of air flow |
Air exchange rate |
Filter class |
|
Operating table area |
||||
|
Area surrounding the operating table |
SANPIN 2.1.3.2630-10 “Sanitary and epidemiological requirements for organizations engaged in medical activities”
6.24. The air supplied to cleanliness class B rooms is subjected to cleaning and disinfection by devices that ensure the efficiency of inactivation of microorganisms at the outlet of the installation by at least 95%, as well as filtration efficiency corresponding to high efficiency filters (H11-H14). (Explanations from Rospotrebnadzor)
For reference: Prior to the release of these sanitary regulations, conventional (fabric or paper) HEPA filters were routinely used in ventilation systems. Such “passive” filters provide only filtration (“retention”) of dust and microorganisms, without providing inactivation (destruction) of microorganisms, while SanPiN 2.1.3.2630-10 require both. Therefore, to meet the requirements of sanitary regulations, conventional HEPA filters for filtration and UV disinfection sections for inactivation were often installed. This expensive solution has many disadvantages: from the high energy consumption of UV sections and a large number of ultraviolet-resistant microorganisms to the presence of fragile lamps containing mercury in the ventilation duct, which contradicts the requirements of Rospotrebnadzor.
6.42. Air recirculation is allowed for one room, provided that a high-efficiency filter (H11-H14) is installed with the addition of outside air according to calculation to ensure standard microclimate parameters and air cleanliness.
8.9.6. Concentrations of harmful chemicals, disinfectants and sterilizing agents, biological factors released into the air during the operation of medical equipment must not exceed the maximum permissible concentrations of maximum permissible concentrations and estimated safe exposure levels established for atmospheric air.
Group 5 according to GOST 52539-2006
Class A according to SanPiN 2.1.3.2630-10
Infectious operating rooms
List of operations performed
- for patients with purulent infection,
- for patients with anaerobic infection
- for tuberculosis patients, etc.
To ensure the safety of people inside and outside the building, the air removed from the infectious operating room must be subjected to class filtration H13 95%
Equipment: Disinfectants and air purifiers for exhaust ventilation ducts:
Laminar ceilings are used to protect the patient and sterile instruments from airborne contamination. The device is built into the hospital ventilation duct directly into the ceiling above the operating table and provides a continuous supply of purified and sterile unidirectional air flow to the operation area. The device must provide air filtration class H14 and inactivation of microorganisms on filters of at least 95%
. Laminar field area: 3-4m2.
Equipment: Laminar ceilings with a cabinet height of 400mm: Tion B Lam-4 (2600×1800×400mm with a niche for a lamp) and for low ceilings with a cabinet height of 290mm: Tion B Lam-4 H290 (3080×1800×290mm with a niche for a lamp).
| Disinfection and purification of indoor air |
To reduce contamination and increase the frequency of air exchange, it is recommended to install autonomous disinfectants of air purifiers (recirculators) with a filtration class of at least H11 and inactivation of microorganisms on filters of at least 99%
Equipment: Air disinfectant-purifier Tion A in mobile and wall-mounted versions
Air purity standards for infectious operating rooms
The priority is to protect staff and other patients. Air from the infectious operating room should not enter adjacent rooms. According to clause 6.18 of SanPiN 2.1.3.2630-10 in infectious diseases departments, exhaust ventilation systems are equipped with air disinfection devices or fine filters that ensure a degree of inactivation (destruction) of microorganisms of at least 95%. GOST R 52539-2006 clause 5.9 requires the provision of a separate ventilation system in infectious rooms using exhaust filters of class H13 installed at the boundary of the room and the exhaust air duct.
GOST R 52539-2006 “Air purity in medical institutions”
clause 5.4. Basic requirements for indoor air purity in equipped condition according to GOST R 52539-2006
5.9. In operating rooms in which patients with purulent, anaerobic and other infections are operated on, it is advisable to provide zones with unidirectional air flow according to 5.7.
5.5. The cross-sectional area of the vertical unidirectional air flow must be at least 3-4 m2. The speed of unidirectional air flow should be in the range from 0.24 to 0.3 m/s. The area with unidirectional air flow should be limited by curtains (shields) along the entire perimeter. Curtains (shields) must be made of transparent materials resistant to disinfectants, usually at least 0.1 m long. The distance from the bottom edge of the curtains (shields) to the floor must be at least 2.1 m.
Due to significant air consumption, to form a unidirectional flow, it is advisable to use a ventilation and air conditioning system with local air recirculation. Local recirculation can use only indoor air, or it can add a certain proportion of outside air.
The separation of the operating room and other rooms is carried out according to one of the principles: pressure difference or displacement air flow. In the latter case, the cleanliness of adjacent rooms can be largely ensured by the flow of air from the operating room. Airlocks may not be provided.
When applying the differential pressure principle, it is recommended to provide continuous (visual or automatic) pressure monitoring.
Rooms for transporting sterile materials (corridors leading to operating rooms) must have a positive pressure drop, including in relation to the operating room. If transportation of sterile materials is carried out in sealed containers (boxes), then the air in the specified rooms (corridors) must be supplied through finishing filters of at least class F9.
5.9. In rooms of group 5, a separate ventilation system must be provided using, if necessary, exhaust filters of class H13 installed at the boundary of the room and the exhaust air duct. The recommended frequency of air exchange is at least 12 hours.
In premises of this group, air recirculation is not allowed.
6.1.
Requirements for outdoor air flow: at least 100 m3/h per person
and not less than 800 m3/h per anesthesia machine.
6.3. Requirements for air exchange and filter classes
|
Group of rooms |
Room (zone) cleanliness class |
Type of air flow |
Air exchange rate |
Filter class |
|
Operating table area |
Not installed |
|||
|
Area surrounding the operating table |
SANPIN 2.1.3.2630-10 “Sanitary and epidemiological requirements for organizations engaged in medical activities”
6.24. (Explanations from Rospotrebnadzor)
For reference: Prior to the release of these sanitary regulations, conventional (fabric or paper) HEPA filters were routinely used in ventilation systems. Such “passive” filters provide only filtration (“retention”) of dust and microorganisms, without providing inactivation (destruction) of microorganisms, while SanPiN 2.1.3.2630-10 require both. Therefore, to meet the requirements of sanitary regulations, conventional HEPA filters for filtration and UV disinfection sections for inactivation were often installed. This expensive solution has many disadvantages: from the high energy consumption of UV sections and a large number of ultraviolet-resistant microorganisms to the presence of fragile lamps containing mercury in the ventilation duct, which contradicts the requirements of Rospotrebnadzor.
6.42. Air recirculation is allowed for one room, provided that a high-efficiency filter (H11-H14) is installed with the addition of outside air according to calculation to ensure standard microclimate parameters and air cleanliness.
8.9.6. Concentrations of harmful chemicals, disinfectants and sterilizing agents, biological factors released into the air during the operation of medical equipment must not exceed the maximum permissible concentrations of maximum permissible concentrations and estimated safe exposure levels established for atmospheric air.
Group 2 according to GOST 52539-2006
Class A according to SanPiN 2.1.3.2630-10
Unidirectional flow intensive care units
Appointment of intensive care and resuscitation wards
The wards are intended for patients:
- after bone marrow transplantation.
- with extensive burns.
— receiving chemotherapy and radiation therapy in high doses.
- after extensive surgical interventions.
- with reduced immunity or its complete absence.
To protect the patient from infection from the air, laminar ceilings are used in intensive care and intensive care wards. The device is built into the ventilation supply duct of a medical facility directly into the ceiling above the patient’s bed and provides a continuous supply of purified and sterile unidirectional air flow to the bed area. The device must provide air filtration class H14 and inactivation of microorganisms on filters of at least 99%
. The area of the laminar floor must cover the bed area and be at least 1.8m2.
Equipment: Laminar ceilings Tion B Lam-2 (1800x1000x400mm); for low ceilings: Tion B Lam-2 H290 (1800x1000x290mm).
Laminar cells
Due to significant air flow rates, in order to form a unidirectional flow over each of the department beds, it may be advisable to use a ventilation system in intensive care with partial air recirculation (part of the air is taken by the ventilation system from the street, and part is mixed from the room) provided that it is not cleaned and disinfected using filters. below grade H14 with inactivation no less 99%
. This allows you to significantly save energy on heating or cooling the supply air by the ventilation system. This method of air exchange can be ensured by installing a laminar ceiling and connecting columns or recirculation modules to it, which ensure the admixture of air from the room.
Equipment: Wall recirculation column -RP suitable for all Tion laminar floors
| Disinfection and purification of indoor air |
To reduce contamination and increase the frequency of air exchange, it is recommended to install autonomous disinfectants of air purifiers (recirculators) with a filtration class of at least H11 and inactivation of microorganisms on filters of at least 99%
Equipment: Air disinfectant-purifier Tion A in mobile and wall-mounted versions
Air cleanliness standards for intensive care and intensive care wards
According to SanPiN 2.1.3.2630-10 clause 6.24 and new SP 118.13330.2012 - Appendix K, the supply air must be cleaned and disinfected by devices that provide a degree of air filtration not lower than class H14 for areas with unidirectional flow and H13 for areas without unidirectional flow, as well as inactivation of microorganisms of at least 99%.
GOST R 52539-2006 “Air purity in medical institutions”
clause 5.4. Basic requirements for indoor air purity in equipped condition according to GOST R 52539-2006
5.6.
In rooms of group 2, the patient’s bed should be in an area of unidirectional air flow with a flow speed of 0.24 to 0.3 m/s. A more economical solution is a vertical air flow, but horizontal air flow can also be used.
Requirements for ventilation and air conditioning, enclosing structures and zones are similar to those for Group 1 premises (5.5).
5.5. The speed of unidirectional air flow should be in the range from 0.24 to 0.3 m/s. The area with unidirectional air flow should be limited by curtains (shields) along the entire perimeter. Curtains (shields) must be made of transparent materials resistant to disinfectants, usually at least 0.1 m long. The distance from the bottom edge of the curtains (shields) to the floor must be at least 2.1 m.
Due to significant air consumption, to form a unidirectional flow, it is advisable to use a ventilation and air conditioning system with local air recirculation. Local recirculation can use only indoor air, or it can add a certain proportion of outside air.
6.1.
6.3. Requirements for air exchange and filter classes
|
Group of rooms |
Room (zone) cleanliness class |
Type of air flow |
Air exchange rate |
Filter class |
|
Patient bed area |
Not installed |
|||
|
Area surrounding the patient's bed |
SANPIN 2.1.3.2630-10 “Sanitary and epidemiological requirements for organizations engaged in medical activities”
6.24. The air supplied to cleanliness class A rooms is subjected to cleaning and disinfection by devices that ensure an efficiency of inactivation of microorganisms at the outlet of the installation of 99%, as well as filtration efficiency corresponding to high efficiency filters (H11-H14). High purity filters must be replaced at least once every six months, unless otherwise provided in the operating instructions. (Explanations from Rospotrebnadzor)
For reference: Prior to the release of these sanitary regulations, conventional (fabric or paper) HEPA filters were routinely used in ventilation systems. Such “passive” filters provide only filtration (“retention”) of dust and microorganisms, without providing inactivation (destruction) of microorganisms, while SanPiN 2.1.3.2630-10 require both. Therefore, to meet the requirements of sanitary regulations, conventional HEPA filters for filtration and UV disinfection sections for inactivation were often installed. This expensive solution has many disadvantages: from the high energy consumption of UV sections and a large number of ultraviolet-resistant microorganisms to the presence of fragile lamps containing mercury in the ventilation duct, which contradicts the requirements of Rospotrebnadzor.
6.42. Air recirculation is allowed for one room, provided that a high-efficiency filter (H11-H14) is installed with the addition of outside air according to calculation to ensure standard microclimate parameters and air cleanliness.
8.9.6. Concentrations of harmful chemicals, disinfectants and sterilizing agents, biological factors released into the air during the operation of medical equipment must not exceed the maximum permissible concentrations of maximum permissible concentrations and estimated safe exposure levels established for atmospheric air.
Group 3 according to GOST 52539-2006
Class B according to SanPiN 2.1.3.2630-10
Aseptic rooms and rooms without unidirectional flow
List of aseptic wards and premises
— wards for patients after internal organ transplantation operations.
— wards for burn patients.
— wards for patients transferred from intensive care wards.
- post-anesthesia wards.
- for weakened or seriously ill non-surgical patients.
- postpartum, including with the child staying together.
— for nursing newborns (second stage).
— preoperative, anesthesia and other rooms leading to operating rooms;
— aspetic dressing and procedural bronchoscopy; storage rooms for sterile materials;
— X-ray operating rooms, including sterilization rooms in operating rooms;
— CSO: clean and sterile areas;
— dialysis rooms, treatment ICUs, barosarooms, assistant and packaging pharmacies, embryology laboratory
To ensure sterile conditions, air in aseptic rooms (sterilization departments, dialysis rooms, etc.) and wards (burn, post-anesthesia, postpartum, etc.) is supplied through a ventilation system with disinfection and cleaning using filters of at least class H11 95%
. Air flow: turbulent.
Equipment: floor-suspended: Tion B (capacity from 300 to 900 m3/h) and Tion B (capacity 2000 and 3000 m3/h); floor-mounted: Tion B (capacity from 300 to 25,000 m3/h).
To reduce the cost of processing external supply air, it is recommended to use air recirculation (taking part of the air from the room) provided that it is cleaned and disinfected using filters of at least class H14 with inactivation no less 95%
Equipment: Wall recirculation column -RP suitable for all Tion laminar floors
| Disinfection and purification of indoor air |
To reduce contamination and increase the frequency of air exchange, it is recommended to install autonomous disinfectants of air purifiers (recirculators) with a filtration class of at least H11 and inactivation of microorganisms on filters of at least 95%
Equipment: Air disinfectant-purifier Tion A in mobile and wall-mounted versions
Air purity standards for aseptic wards and premises
The air must be treated with devices that filter particles with a class of at least H13 (SP 118.13330.2012 Appendix K), inactivate (destroy) microorganisms with an efficiency of at least 95% (SanPiN 2.1.3.2630-10 clause 6.24), and clean the air from harmful substances up to the MPC level (No. 384-FZ).
GOST R 52539-2006 “Air purity in medical institutions”
clause 5.4. Basic requirements for air purity in aseptic rooms and rooms with turbulent air flow according to GOST R 52539-2006
In rooms of group 3, air filtration is provided with an air exchange rate that ensures a given cleanliness class.
In rooms of group 3 it is allowed to use air recirculation.
The separation of rooms of group 3 and other rooms is carried out according to one of the principles: displacement flow or pressure difference. Continuous monitoring of these parameters and airlocks are not provided in Group 3 premises.
In burn departments for patients with extensive burns there should be rooms (zones) of cleanliness class 5ISO, equipped with a vertical unidirectional air flow to blow the affected areas of the body.
For cases where it is necessary to blow air over the affected areas of the body from different sides, it is recommended to use autonomous air purification devices to prevent contaminants from entering the affected areas.
6.1. Requirements for outdoor air flow: at least 100 m3/h per person.
6.3. Air exchange rate - 12-20 times/hour, air flow: non-unidirectional
SANPIN 2.1.3.2630-10 “Sanitary and epidemiological requirements for organizations engaged in medical activities”
6.24. The air supplied to cleanliness class B rooms is subjected to cleaning and disinfection by devices that ensure an efficiency of inactivation of microorganisms at the outlet of the installation of 95%, as well as filtration efficiency corresponding to high efficiency filters (H11-H14). High purity filters must be replaced at least once every six months, unless otherwise provided in the operating instructions. (Explanations from Rospotrebnadzor)
For reference: Prior to the release of these sanitary regulations, conventional (fabric or paper) HEPA filters were routinely used in ventilation systems. Such “passive” filters provide only filtration (“retention”) of dust and microorganisms, without providing inactivation (destruction) of microorganisms, while SanPiN 2.1.3.2630-10 require both. Therefore, to meet the requirements of sanitary regulations, conventional HEPA filters for filtration and UV disinfection sections for inactivation were often installed. This expensive solution has many disadvantages: from the high energy consumption of UV sections and a large number of ultraviolet-resistant microorganisms to the presence of fragile lamps containing mercury in the ventilation duct, which contradicts the requirements of Rospotrebnadzor.
6.42. Air recirculation is allowed for one room, provided that a high-efficiency filter (H11-H14) is installed with the addition of outside air according to calculation to ensure standard microclimate parameters and air cleanliness.
8.9.6. Concentrations of harmful chemicals, disinfectants and sterilizing agents, biological factors released into the air during the operation of medical equipment must not exceed the maximum permissible concentrations of maximum permissible concentrations and estimated safe exposure levels established for atmospheric air.
Group 5 according to GOST 52539-2006
Class B according to SanPiN 2.1.3.2630-10
Premises of infectious diseases departments and biological laboratories
List of infectious diseases premises
— wards, boxes (including tuberculosis rooms).
— dressing rooms, airlocks and other rooms of infectious diseases departments.
— rooms and boxes of microbiological laboratories working with pathogenic microorganisms (aerosol chambers; boxed rooms; microbiological rooms)
To ensure the safety of people in the building and outside it, the air removed from infectious diseases wards and boxes, as well as premises of biological laboratories working with pathogenic microorganisms, must be subjected to class filtration H13 and inactivation (complete destruction) of microorganisms on filters of at least 95%
Equipment: Duct disinfectants-cleaners in the exhaust ventilation duct:
Tion V (capacity from 300 to 900 m3/h) and Tion V (capacity 2000 and 3000 m3/h)
Supply air is supplied through a ventilation system with disinfection and cleaning using filters of at least class H11 with inactivation of microorganisms no less than 95%.
Equipment: Floor-mounted duct disinfection-cleaners: Tion B (capacity from 300 to 900 m3/h) and Tion B (capacity 2000 and 3000 m3/h); floor-mounted: Tion V (capacity from 300 to 2400 m3/h) and Tion V (capacity from 2000 to 25000 m3/h)
| Disinfection and purification of indoor air |
To reduce contamination and increase the frequency of air exchange, it is recommended to install autonomous disinfectants of air purifiers (recirculators) with a filtration class of at least F9 and inactivation of microorganisms on filters of at least 95%
Equipment: Air disinfectant-purifier Tion A in mobile and wall-mounted versions
Air purity standards for infectious diseases premises
Deletable The air from infectious rooms must be treated with devices that filter particles with class not lower than H13(SP 118.13330.2012 Annex K), inactivate (destroy) microorganisms with an efficiency no lower 95% (SanPiN 2.1.3.2630-10 clause 6.24), purify the air from harmful substances to the level of maximum permissible concentrations (No. 384-FZ).
For reference:
Supply The air entering infectious diseases departments and premises of biological laboratories, according to SP 118.13330.2012 Appendix K, must be cleaned using class filters from H11 to H13.
GOST R 52539-2006 “Air purity in medical institutions”
clause 5.4. Basic requirements for air purity in infectious diseases rooms according to GOST R 52539-2006
5.9. In rooms of group 5, a separate ventilation system must be provided using, if necessary, exhaust filters of class H13 installed at the boundary of the room and the exhaust air duct.
To reduce supply air consumption and ensure a given air exchange rate, autonomous air purification devices can be used
Entry into and exit from the room must be organized through an active airlock (airlock with a forced supply of clean air). Air from the airlock can be supplied to the isolator.
The cleanliness class of the airlock must be no lower than the room cleanliness class of group 5 (isolators).
In isolators, it is necessary to maintain negative pressure in relation to adjacent rooms, including the airlock. The pressure drop must be at least 15 Pa, and its continuous (visual or automatic) monitoring must be ensured. Visual and audible signaling of simultaneous opening of doors must be provided.
6.4 In rooms of groups 3-5, in order to increase the air exchange rate, reduce the load on the central air conditioner and ensure a differential air pressure (positive or negative), they can be used standalone devices air purification with final filters class not lower than F9. To ensure a higher level of cleanliness in the room, devices can have final filters of classes H12, H13 and H14.
SANPIN 2.1.3.2630-10 “Sanitary and epidemiological requirements for organizations engaged in medical activities”
6.18. In infectious diseases departments, including tuberculosis departments, exhaust ventilation systems are equipped with air disinfection devices or fine filters.
6.19. Boxes and boxed wards are equipped with autonomous ventilation systems with a predominance of air exhaust over the supply air and the installation of air disinfection devices or fine filters on the exhaust hood. When installing disinfection devices directly at the exit from premises, it is possible to combine the air ducts of several boxes or boxed wards into one exhaust ventilation system.
6.20. In existing buildings, in the absence of mechanically driven supply and exhaust ventilation in infectious diseases departments, natural ventilation must be equipped with the obligatory equipment of each box and boxed ward with air disinfection devices that ensure the effectiveness of inactivation of microorganisms no less than 95% at the exit.
8.9.6. Concentrations of harmful chemicals, disinfectants and sterilizing agents, biological factors released into the air during the operation of medical equipment must not exceed the maximum permissible concentrations of maximum permissible concentrations and estimated safe exposure levels established for atmospheric air.
Air purity standards for biological laboratories
According to the conclusion of the Anti-Plague Center of Rospotrebnadzor, microbiological laboratories carrying out work with pathogenic (dangerous) microorganisms equal to infectious diseases departments, therefore, their mechanically driven exhaust ventilation must be equipped with air disinfection devices and antibacterial filters that ensure efficient air filtration not lower than H13, as well as continuous inactivation (destruction) microorganisms of pathogenicity groups 1-4.
For reference: Until recently, conventional (fabric or paper) HEPA filters were commonly used in ventilation systems. Such “passive” filters provide only filtration (“retention”) of dust and microorganisms, without providing inactivation (destruction) of microorganisms, while SanPiN 2.1.3.2630-10 require both. Therefore, to meet the requirements of sanitary regulations, conventional HEPA filters for filtration and UV disinfection sections for inactivation were often installed. This expensive solution has many disadvantages: from the high energy consumption of UV sections and a large number of ultraviolet-resistant microorganisms to the presence of fragile lamps containing mercury in the ventilation duct, which contradicts the requirements of Rospotrebnadzor.
Safety of working with microorganisms of pathogenicity groups 3–4
sanitary and epidemiological rules SP 1.2.731-99
4.2.10. Newly constructed and reconstructed laboratories should provide:
— a device for autonomous supply and exhaust ventilation with the installation of fine filters for air emitted from the “infectious” zone (or equipping these premises with biological safety cabinets).
4.2.16. Existing exhaust ventilation from the “infectious” zone of the laboratory must be isolated from other ventilation systems and equipped with fine air filters.
4.2.21. Premises where work with live pathogenic pathogens is carried out must be equipped with bactericidal lamps in accordance with the “Guidelines for the use of bactericidal lamps for disinfecting air and surfaces in premises.”
4.5.2. Boxes for placing an aerosol chamber, keeping animals and opening them must be equipped with mechanical supply and exhaust ventilation with fine air filters, and have a backup exhaust motor with automatic switching.
Safety of working with microorganisms of pathogenicity (hazard) groups 1-2
sanitary and epidemiological rules SP 1.3.1285-03
2.3.16. The premises of the unit for working with infected animals, boxed rooms, microbiological rooms must have an autonomous supply and exhaust ventilation system, isolated from other ventilation systems of the building, equipped with fine filters at the outlet, tested for protective effectiveness.
2.6.2. All vacuum lines, compressed air and gas lines in the “contaminated” zone are provided with fine air filters (FPO).
2.7.3. The premises of the “contagious” zone must be equipped with supply and exhaust mechanical ventilation systems with fine filters that provide:
Maintaining vacuum in the premises with constant automatic regulation of its parameters and their registration; it is allowed in the premises of the “contagious” zone of existing structures to create and regulate vacuum in other ways;
Creation of directed air flows, the presence of which is controlled by personnel;
Purification of air entering and removed from premises using the required number of cascades of fine filters;
Maintaining the required sanitary and hygienic conditions in the premises.
2.16.13 The structures of any types of aerosol chambers must be sealed, ensure a constant vacuum inside the working volume of at least 150 Pa (15 mm of water column) and be equipped with an air purification (decontamination) system.
2.16.14 The air purification system includes fine filters (FPO): one stage at the air inlet and two stages at the outlet. — functional diagnostic rooms, procedural endoscopies (gastroduodenoscopy, colonoscopy, retrograde cholangiopancreatography, etc. except bronchoscopy).
— physical therapy rooms
— procedural magnetic resonance imaging
- procedural with the use of chlorpromazine
— procedural for treatment with neuroleptics
— installation and washing rooms for artificial kidneys, endoscopy, heart-lung machines, solution-demineralization rooms.
— bathrooms (except radon), paraffin and ozokerite heating rooms, therapeutic swimming pools
— control rooms, staff rooms, patient rest rooms after procedures
- treatment rooms and dressing rooms for X-ray diagnostic, fluorography rooms, electrophototherapy rooms, massage room
— control rooms for X-ray rooms and radiology departments, photo laboratories
— premises (rooms) for sanitary treatment of patients, showers
- changing rooms in the water and mud treatment departments
— rooms for radon baths, halls and mud therapy rooms for strip procedures, shower rooms
— premises for storing and regenerating dirt
— premises for the preparation of hydrogen sulfide bath solution and storage of reagents
— rooms for washing and drying sheets, canvases, tarpaulins, mud kitchens
— storerooms (except for storing reagents), technical rooms (compressor rooms, pump rooms, etc.), equipment repair shops, archives
— sanitary rooms, rooms for sorting and temporary storage of dirty linen, rooms for washing, stretchers and oilcloths, room for drying clothes and shoes of visiting teams
— storehouses of acids, reagents and disinfectants
- registries, information lobbies, dressing rooms, rooms for receiving packages for patients, discharge rooms, waiting rooms, pantries, dining rooms for patients, a dairy room.
- a room for washing and sterilizing tableware and kitchen utensils in the pantry and dining rooms, hairdressing salons for serving patients
— storage of radioactive substances, packaging and washing in radiological departments
— rooms for x-ray and radiotherapy
— rooms for electro-, light-, magneto-, heat and ultrasound treatment
— premises of disinfection chambers: receiving and loading rooms; unloading (clean) compartments
- sectional rooms, museums and preparation rooms in pathology departments
- rooms for dressing corpses, issuing corpses, storage rooms for funeral supplies, for processing and preparing for burial of infected corpses, storage rooms for bleach
— bathrooms
- enema
— clinical diagnostic laboratories (rooms for research)
| Ensuring frequency of air exchange and air cleanliness standards |
In wards for adult patients, offices, examination rooms and other rooms without aseptic conditions, the filtration of supply air of class F7-F9 is regulated, and the air exchange rate must be ensured, in accordance with Appendix 3 to SanPiN 2.1.3.2630-10. This is achieved by central ventilation with air purification, or, in its absence, by installing compact supply ventilation with air purification in each individual room.
Tion A in mobile and wall-mounted versions
Air purity standards
SP 118.13330.2012 regulates filtration supply air class F7-F9, while the air exchange rate must be ensured, in accordance with Appendix 3 to SanPiN 2.1.3.2630-10.
GOST R 52539-2006 “Air purity in medical institutions”
clause 5.4. Basic requirements for air purity according to GOST R 52539-2006
For patients suspected of having active tuberculosis or other infectious diseases, rooms should be provided that are separated by doors from the rest of the emergency department. Ventilation of these premises must meet the requirements for Group 5 premises (isolators).
SANPIN 2.1.3.2630-10 “Sanitary and epidemiological requirements for organizations engaged in medical activities”
List of premises
— premises for the preparation of dosage forms under aseptic conditions
- assistant, defector, procurement and packaging, seaming and control and marking, sterilization-autoclave, distillation
— control and analytical, washing, unpacking
— main stock storage premises:
a) medicinal substances, finished medicinal products, incl. and thermolabile and medical supplies; dressings
b) mineral waters, medical glass and returnable transport containers, glasses and other optical items, auxiliary materials, clean dishes
— premises for the preparation and packaging of poisonous drugs and drugs, flammable and combustible liquids
Unidirectional airflow devices are used to protect critical operations such as filling and capping from airborne contamination. The laminar ceiling or cell is built into the ventilation duct directly into the ceiling above the work area and provides a continuous supply of purified and sterile unidirectional air flow. The device must provide air filtration class H14 and inactivation of microorganisms on filters of at least 99%
(requirements for class A according to SanPiN 2.1.3.2630-10). The area of the laminar field of the device is selected depending on the area of the clean production working area.
Equipment: Laminar cells Tion B Lam-M1 (600x600x400mm), Tion B Lam-M2 (1200x600x400mm)
Laminar ceilings Tion B Lam-2 (1800x1000x400mm); for low ceilings: Tion B Lam-2 H290 (1800x1000x290mm)
| Disinfection and purification of supply air |
In the assistant's, defector's, procurement and packaging, seaming and control-labeling, sterilization-autoclave and distillation rooms, supply air is supplied through a ventilation system with disinfection and cleaning using filters of at least class H11 with inactivation of microorganisms no less than 95%
(requirements for class B according to SanPiN 2.1.3.2630-10). Since air exchange rates are low and amount to no more than 4 times, in small rooms up to 50 m2 it is advisable to install compact supply ventilation (without laying air ducts) with air purification instead of central ventilation.
In the premises of pharmacies: control and analytical, washing, unpacking, as well as warehouses for storing supplies, there are no requirements for air purity, but air exchange standards apply. They are achieved by installing a central supply and exhaust ventilation system, or, if it is impossible or absent, by installing compact supply ventilation with air purification in each individual room.
Air purity standards for pharmacies
The ventilation of the pharmacy must ensure a temperature of at least +18 and not higher than +20 degrees, air flow speed from 0.1 to 0.2 m/s and air humidity from 30% to 60%.
When choosing a ventilation system, it is necessary to take into account that it is necessary to exclude the entry of dirt, dust and microorganisms from the street into the room. Therefore, among all types of ventilation systems, preference is given to supply ventilation with air cleaning and disinfection. According to clause 5.16 of SanPiN 2.1.3.2630-10, all parenteral solutions are prepared in a pharmacy in a cabinet with laminar air flow, using aseptic technology.
Guidelines MosMU 2.1.3.005-01
7.1.
Heating and ventilation systems must be carried out in accordance with current SNiP (SP 118.13330.2012).
7.2.
To exclude the possibility of air masses entering from corridors and production rooms into the aseptic block between these rooms, it is necessary to install a gateway with air pressure.
7.3.
The aseptic unit must be equipped with autonomous supply and exhaust ventilation with a predominance of inflow.
7.4.
The movement of air flows must be ensured from the aseptic unit to the adjacent rooms.
Supply of purified air to aseptic rooms can be carried out through supply holes in the ceiling with a vertical air flow or through holes in one of the side walls with a horizontal air flow. Allowed use of autonomous devices dust removal (or filtration) of air installed indoors, creating horizontal or vertical laminar flows throughout the entire premises or in specific local areas to protect the most critical areas or operations.
Filling and capping is carried out under laminar air flow.
“Clean” chambers (or tables with a laminar flow of clean air) must have working surfaces and guides made of smooth, durable material. The laminar flow speed should be within 0.3 m/s.
7.5.
Natural exhaust ventilation without a centralized supply of supply air is allowed for detached buildings with a height of no more than 3 floors.
7.6.
In each institution, an order must appoint an employee responsible for the operation of ventilation systems.
7.7.
The use of ventilation chambers for other purposes (storage, storage of chemical materials, etc.) is not permitted.
7.8.
The operating organization must monitor the efficiency of ventilation systems (air exchange rate, temperature, humidity and purity of the supplied air).
Design temperatures, air exchange rates, air purity
| t air not lower | Name of departments | Room class according to SanPiN 2.1.3.2630-10 | Air exchange rate, mechanical ventilation | Natural exhaust ratio. air exchange | Filtration air |
|
| influx | hood | |||||
| 16°C | Public service halls | — | 3 | 4 | 3 | no requirements |
| 18°C | Placement of orders from attached pharmacies, for receiving and processing orders, prescription | — | 2 | 1 | 1 | no requirements |
| 18°C | Assistant, defector, procurement, packaging, sterilization-autoclave, distillation | B | 4 | 2 | 1 | H11 to H13 |
| 18°C | Control and analytical, sterilization solutions, unpacking | B | 2 | 3 | 1 | H11 to H13 |
| 18°C | Premises for the preparation of medicines under aseptic conditions | A | 4 | 2 | not allowed | H14 in unidirectional flow area |
| Stock storage premises: | ||||||
| 18°C | a) medicinal substances, dressings, thermolabile drugs and medical supplies | G | 2 | 3 | 1 | no requirements |
| 18°C | b) medicinal plant materials | G | 3 | 4 | 3 | no requirements |
| 18°C | c) poisonous drugs and drugs | G | — | 3 | 3 | no requirements |
| 18°C | d) flammable and combustible liquids | G | — | 10 | 5 | no requirements |
| 18°C | e) disinfectants, acids | G | — | 5 | 3 | no requirements |
Is it possible to use glycol in installations of supply ventilation systems?
When designing buildings in areas with a design outdoor temperature of –40 °C and below (according to parameters B), it is allowed to use water with additives that prevent it from freezing. Accordingly, the use of an aqueous glycol solution is possible to eliminate the risk of freezing of air heaters.
Are there regulations for MRI rooms?
There are no special rules.
Are there premises in medical buildings with category A for fire and explosion hazard?
The classification of health care facilities by production categories according to ONTP 24-86 is given in PPBO 07-91 “Fire Safety Rules for Healthcare Institutions.” In accordance with them, category A includes: premises for storing flammable liquids, storing gas cylinders, paint shops, battery (charging) rooms.
What heating devices are used in the wards of psychiatric hospitals?
Devices with a smooth surface that are resistant to daily exposure to detergents and disinfectants should be used, eliminating the accumulation of dust and microorganisms in all rooms.
How to maintain indoor humidity when using ventilation systems?
For ward rooms during the cold season, you can, for example, use steam humidifiers.
Is it possible to use split systems and fan coils in medical institutions?
Regarding split systems: “the use of split systems is allowed in the presence of high efficiency filters (H11-H14) subject to mandatory compliance with the rules of routine maintenance. Split systems must have a positive sanitary and epidemiological certificate issued in accordance with the established procedure,” that is, a certificate for the possibility of use in medical institutions. We can recommend installing split systems and fan coils in administrative and auxiliary premises. The use of this equipment in medical premises does not provide the required air mobility (0.15–0.2 m/s); in addition, fan coils create background noise that exceeds the permissible values (There are known cases of using fan coils to remove excess heat from equipment in technical rooms KRT.)
Is there a clear requirement for a mandatory certificate for ventilation and air conditioning equipment used in medical institutions?
There are no such requirements in the existing regulatory literature; however, medical equipment must be accepted for installation in healthcare facilities.
How to design ventilation in small built-in or attached dental departments occupying a floor or part of a floor in a building?
It is necessary to provide an independent supply and exhaust ventilation system for the dental department; the influx into the X-ray room can be carried out from a general supply ventilation system with the installation of a check valve; independent exhaust must be provided. Operating rooms require an independent air conditioning system with three stages of supply air purification and the use of a class H filter at the final stage.
Is it possible to serve operating rooms that are part of different departments (“dirty”) and located on different floors with one supply system?
As a rule, these are departments for various technological purposes. The operating room must have cleanliness class A. To avoid the transfer of infection of one type or another between operating rooms through the ventilation system, each operating room (the operating unit of each department) for the case under consideration should be served with an independent supply and exhaust system. If there are several operating rooms in one operating block, they should be combined to be served by one ventilation system.
Do the requirements for operating rooms in clinics need to be the same as the requirements for operating rooms in hospitals?
Yes, you should. The operating room of the clinic is considered as a small operating room, in which the air supply should be carried out through air distributors of slightly turbulent flow.
What filters are used in health care facilities?
To ensure the required class of room cleanliness, it is necessary to provide for the installation of filters and air disinfection devices in ventilation and air conditioning systems.
Ventilation and air conditioning systems for rooms of classes A and B should be equipped with a three-stage system for purification and disinfection of supply air; rooms of other classes may be equipped with a two-stage system.
Air purification filters are used for individual filtration stages. General purpose air filters (coarse and fine filters), as a rule, are used depending on the cleaning stage:
For stage 1 - coarse cleaning group of class not lower than G4 pocket type or F5 (or higher, as an option) depending on the pollution of the outside air;
For stage 2 – fine cleaning group of class not lower than F7;
For stage 3 – high efficiency group of class not lower than H11 and/or air disinfection devices with an efficiency of inactivation of microorganisms and viruses of at least 95%.
When using a filter of class F5 and higher as the 1st stage of cleaning, it is recommended (to extend the service life of the 2nd stage filters) to install an additional pre-cleaning filter of class G3 or G4 in front of the 1st stage filter.
Filters of cleaning stages 1 and 2 are placed directly in the supply ventilation or air conditioning systems:
Stage 1 – at the entrance of outside air to the supply unit to protect the elements of the supply chamber from particles;
Stage 2 – at the outlet of the air handling unit to protect air ducts from particles.
Filters of purification stage 3 are placed as close as possible to the serviced room or in the serviced room itself after the air disinfection device (if necessary).
When choosing an air purification scheme for rooms of cleanliness classes A and B, it is necessary to take into account the indicators of background dust concentrations in the atmospheric air requested from the territorial bodies of Roshydromet. The choice of air purification scheme is carried out in agreement with the territorial bodies of Rospotrebnadzor.
How to humidify the air?
In accordance with the above standards, air humidification should be done with steam (steam generator). Air humidification with water is permissible provided it is disinfected.
The design of air humidification devices and their location must prevent the formation of condensation and drops of moisture after the humidifier and their entry into the supply ventilation system. Air humidification devices of nozzle or film type are installed before the final filtration stage. In case of air humidification with steam, it is recommended to install the steam distribution device directly in the air duct. These devices should be placed in a place accessible for maintenance, cleaning and disinfection.
The steam humidifier is connected to the water supply for replenishment. To ensure reliable operation, it must meet the water quality requirements of the manufacturer.
To reduce the concentration of microorganisms, water should be disinfected.
What air conditioners should be installed in health care facilities?
The equipment of air conditioning (ventilation) systems must be of medical grade.
Description:
Operating rooms are one of the most critical links in the structure of a hospital building in terms of the importance of the surgical process, as well as providing the special microclimate conditions necessary for its successful implementation and completion. Here, the source of the release of bacterial particles is mainly medical personnel, who are able to generate particles and release microorganisms when moving around the room.
Hospital operating rooms
Air flow control
Over the past decades, in our country and abroad, there has been an increase in purulent-inflammatory diseases caused by infections, which, according to the definition of the World Health Organization (WHO), are commonly called nosocomial infections (HAIs). An analysis of diseases caused by nosocomial infections shows that their frequency and duration are directly dependent on the state of the air environment in hospital premises. To ensure the required microclimate parameters in operating rooms (and industrial clean rooms), unidirectional flow air distributors are used. The results of monitoring the air environment and analyzing the movement of air flows showed that the operation of such distributors provides the required microclimate parameters, but often worsens the bacteriological purity of the air. To protect the critical area, it is necessary that the air flow leaving the device maintains straightness and does not lose the shape of its boundaries, that is, the flow should not expand or contract over the protected area where the surgical
Operating rooms are one of the most critical links in the structure of a hospital building in terms of the importance of the surgical process, as well as providing the special microclimate conditions necessary for its successful implementation and completion. Here, the source of the release of bacterial particles is mainly medical personnel, who are able to generate particles and release microorganisms when moving around the room. The intensity of particles entering indoor air depends on the degree of mobility of people, temperature and air speed in the room. Nosocomial infections tend to move around the operating room with air currents, and there is always a risk of its penetration into the unprotected wound cavity of the patient being operated on. From observations it is obvious that improperly organized operation of ventilation systems leads to intensive accumulation of infection to levels exceeding permissible levels.
For several decades, specialists from different countries have been developing system solutions to ensure air conditions in operating rooms. The air flow supplied to the room must not only assimilate various harmful substances (heat, humidity, odors, harmful substances) and maintain the required microclimate parameters, but also ensure the protection of strictly established areas from infections entering them, that is, the necessary cleanliness of indoor air. The area where invasive interventions are carried out (penetration into the human body) can be called the operating zone or “critical”. The standard defines such an area as an “operating sanitary protection zone” and means by it the space where the operating table, auxiliary tables for instruments and materials, equipment, as well as medical personnel in sterile clothing are located. There is the concept of a “technological core”, which refers to the area where production processes are carried out under sterile conditions, which in meaning can be correlated with the operating area.
To prevent the penetration of bacterial contaminants into the most critical areas, screening methods have become widely used through the use of displacement air flow. Various designs of laminar air flow air distributors were created, and the term “laminar” was later changed to “unidirectional” flow. Currently, you can find a variety of names for air distribution devices in clean rooms, such as “laminar”, “laminar ceiling”, “operating ceiling”, “clean air operating system”, etc., which does not change their essence. The air distributor is built into the ceiling structure above the protection zone of the room and can be of different sizes depending on the air flow. The recommended optimal area of such a ceiling should be at least 9 m2 in order to completely cover the operating area with tables, equipment and personnel. The displacing air flow at low speeds comes from top to bottom, like a curtain, cutting off both the aseptic field of the surgical intervention zone and the zone of transfer of sterile material from the environment. Air is removed from the lower and upper zones of the room simultaneously. HEPA filters (class H according to) are built into the ceiling structure, through which the supply air passes. Filters trap but do not disinfect living particles.
Currently, much attention is being paid all over the world to the issues of air disinfection in hospitals and other institutions where there are sources of bacterial contamination. The documents voiced requirements for the need to disinfect operating room air with a particle inactivation efficiency of at least 95%, as well as air ducts and climate system equipment. Bacterial particles released by surgical personnel continuously enter the room air and accumulate in it. To ensure that the concentration of particles in indoor air does not reach maximum permissible levels, air control is necessary. Such monitoring must be carried out after installation of climate control systems, maintenance or repair, that is, in the operating mode of a clean room.
The use of unidirectional flow air distributors with built-in ceiling-type ultra-fine filters in operating rooms has become common among designers. Air flows of large volumes go down the room at low speeds, cutting off the protected area from the environment. However, many professionals are unaware that these solutions are not sufficient to maintain adequate levels of air disinfection during surgical procedures.
The fact is that there are quite a lot of designs of air distribution devices, each of which has its own area of application.
The first examples of the use of air distributors for clean rooms appeared in the mid-1950s. Since then, it has become traditional to distribute air in clean production rooms through a perforated ceiling when low concentrations of particles or microorganisms are required. The air flow moves through the entire volume of the room in one direction at a uniform speed, usually 0.3–0.5 m/s. The air is supplied through a bank of high-efficiency air filters located on the ceiling of the cleanroom. The air supply is organized on the principle of an air piston moving downward through the entire room, removing contaminants. Air removal occurs through the floor. This type of air movement contributes to the removal of aerosol contaminants, the sources of which are personnel and processes. This arrangement of ventilation is aimed at ensuring clean air in the room, but requires large air flows and is therefore uneconomical. For cleanrooms of class 1000 or ISO class 6 (ISO classification), the air exchange rate can range from 70 to 160 times per hour.
Subsequently, more rational modular devices appeared, with significantly smaller sizes and low costs, which made it possible to select an air supply device based on the size of the protected area and the required air exchange rates of the room, depending on the purpose of the room.
Analysis of the operation of laminar air distributors
Laminar flow units are used in clean production rooms and serve to distribute large volumes of air, providing for specially designed ceilings, floor hoods and room pressure regulation. Under these conditions, the operation of laminar flow distributors is guaranteed to provide the required unidirectional flow with parallel flow lines. A high air exchange rate helps maintain conditions close to isothermal in the supply air flow. Ceilings designed for air distribution with large air exchanges, due to their large area, provide a low initial air flow velocity.
However, when such air distributors operate in an operating room, the situation changes significantly. To maintain acceptable levels of bacteriological purity of air in operating rooms, calculated air exchange values usually average 25 times per hour or even less, that is, they are not comparable with the values for industrial premises. To maintain stable air flow between the operating room and adjacent rooms, excess pressure is usually maintained in it. Air is removed through exhaust devices symmetrically installed in the walls of the lower zone of the room.
Observations show that such laminar devices will not always provide unidirectional flow. Since there is almost always a difference between the temperature in the supply stream and the ambient air temperature (5-7 ° C), the cooler air leaving the supply device descends much faster than an isothermal unidirectional flow. This is a common occurrence for ceiling diffusers used in public buildings. There is a misconception that laminar floors provide stable, unidirectional airflow regardless of location or method of application. In fact, in real conditions, the speed of low temperature vertical laminar flow will increase as it approaches the floor. The larger the volume of supply air and the lower its temperature relative to the room air, the greater the acceleration of its flow. The table shows that the use of a laminar system with an area of 3 m 2 with a temperature difference of 9 ° C gives a threefold increase in air speed already at a distance of 1.8 m from the beginning of the path. The air speed at the outlet of the supply device is 0.15 m/s, and at the level of the operating table it reaches 0.46 m/s. This value exceeds the acceptable level. It has long been proven by many studies that with excessive inflow flow rates it is impossible to maintain its “unidirectionality”. Analysis of air control in operating rooms, carried out, in particular, by Salvati (1982) and Lewis (Lewis, 1993), showed that in some cases the use of laminar flow units with high air velocities leads to an increase in the level of air contamination in the area of the surgical incision with subsequent risk of infection.
| Dependence of air flow speed on area laminar panel and supply air temperature |
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T - difference between the temperature of the supply and ambient air |
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When the flow moves, at the initial point the air flow lines will be parallel, then the boundaries of the flow will change, narrowing towards the floor, and it will no longer be able to protect the area determined by the dimensions of the laminar flow unit. At air speeds of 0.46 m/s, the flow will capture low-moving air from the room. Since bacterial particles are constantly released in the room, infected particles will be mixed into the air flow coming from the supply unit, since the sources of their release are constantly operating in the room. This is facilitated by air recirculation resulting from pressurized air in the room. To maintain the cleanliness of operating rooms, according to the standards, it is necessary to ensure an imbalance of air due to the excess of the inflow over the exhaust by 10%. Excess air moves to adjacent less clean rooms. In modern conditions, hermetic sliding doors are often used in operating rooms; excess air has nowhere to go; it circulates throughout the room and is taken back into the supply unit using fans built into it for further cleaning in filters and secondary supply to the room. The circulating air collects all contaminated particles from the air in the room and, moving near the supply flow, can pollute it. Due to the violation of the boundaries of the flow, air from the surrounding space is mixed into it and pathogenic particles penetrate into the sterile zone, which is considered protected.
High mobility promotes intensive detachment of dead skin particles from unprotected areas of the skin of medical personnel and their entry directly into the surgical incision. On the other hand, it should be noted that the development of infectious diseases in the postoperative period is caused by the hypothermic state of the patient, which intensifies when exposed to flows of cold air of increased mobility.
Thus, a laminar flow air diffuser, traditionally used and effective in a cleanroom environment, may be detrimental to operations in a conventional operating room.
This conversation is valid for laminar flow devices, which have an average area of about 3 m 2 - optimal for protecting the operating area.
According to American requirements, the air flow velocity at the outlet of laminar panels should not exceed 0.15 m/s, that is, 14 l/s of air should flow into the room from 1 ft 2 (0.09 m 2) of panel area. In our case, this will be 466 l / s (1677.6 m 3 / h) or approximately 17 times / h. According to the standard value of air exchange in operating rooms, it should be 20 times per hour, 25 times per hour, so 17 times per hour fully meets the requirements. It turns out that the value of 20 times per hour corresponds to a room with a volume of 64 m 3.
According to today's standards, the area of a standard operating room (general surgery) should be at least 36 m2. And the requirements for operating rooms for more complex operations (cardiological, orthopedic, etc.) are much higher, and often the volume of such an operating room can exceed 135–150 m 3 . The air distribution system for these cases will require a significantly larger area and air capacity.
In the case of organizing air flow in larger operating rooms, the problem arises of maintaining laminarity of flow from the exit plane to the level of the operating table. Air flow behavior studies have been conducted in several operating rooms. Laminar flow panels were installed in different rooms, which were divided by area into two groups: 1.5–3 m 2 and more than 3 m 3, and experimental air conditioning units were installed that made it possible to change the temperature of the supply air.
Repeated measurements of the flow rate of incoming air were carried out at various flow rates and temperature changes, the results of which can be seen in the table.
For example, the standard considers disinfection to be the main goal of its requirements, noting: “a properly designed HVAC system minimizes the airborne transmission of viruses, bacteria, fungal spores and other biological contaminants,” and HVAC systems play a major role in controlling infections and other harmful factors. The requirement for operating room air conditioning systems is highlighted: “the air supply system must be designed to minimize the introduction of bacteria into sterile areas along with the air, while also maintaining the maximum level of cleanliness in the rest of the operating room.”
However, regulatory documents do not contain direct requirements for determining and monitoring the effectiveness of disinfection for various ventilation methods, and designers often have to engage in search activities, which takes a lot of time and distracts from the main work.
In our country there is quite a lot of different regulatory literature on the design of HVAC systems for hospital buildings, and requirements for air disinfection are voiced everywhere, which, for many objective reasons, are practically difficult for designers to implement. This requires not only knowledge of modern disinfection equipment and the correct use of it, but, most importantly, further timely epidemiological monitoring of the indoor air environment, which gives an idea of the quality of operation of HVAC systems, but, unfortunately, is not always carried out. If the cleanliness of clean industrial premises is assessed by the presence of particles (for example, dust particles), then the indicator of air cleanliness in clean rooms of medical buildings is live bacterial or colony-forming particles, the permissible levels of which are given in. To maintain these levels, the air environment should be regularly monitored for microbiological indicators, for which it is necessary to be able to count them. The methodology for collecting and counting microorganisms to assess air purity has not yet been presented in any of the regulatory documents. It is important that the counting of microbial particles should be carried out in the operating room, that is, during the operation. But for this, the design and installation of the air distribution system must be ready. The level of disinfection or the efficiency of the system cannot be determined before it starts operating in the operating room; this can only be done under conditions of at least several operating processes. This poses great difficulties for engineers, since research, although necessary, is contrary to the hospital’s anti-epidemic discipline.
Air curtain
To ensure the required air conditions in the operating room, it is important to properly organize the joint work of air inflow and removal.
In operating rooms, it is impossible to use both the entire ceiling area for air distribution and the floor area for air removal.
Floor hoods are unhygienic because they get dirty quickly and are difficult to clean. Bulky, complex and expensive systems have never found their application in small operating rooms. For these reasons, the most rational is the “island” arrangement of laminar panels above the critical area with the installation of exhaust openings in the lower part of the walls. This makes it possible to simulate air flows similar to an industrial clean room in a cheaper and less cumbersome way. A method that has proven successful is the use of air curtains operating on the principle of a protective barrier.
The air curtain combines well with the flow of supply air in the form of a narrow “shell” of air at a higher speed, specially organized around the perimeter of the ceiling. The air curtain continuously works for exhaust and prevents the entry of contaminated ambient air into the laminar flow.
From Fig. Figure 3 shows the values of the actual (measured) speed that occurs with a properly designed air curtain, which clearly demonstrate the interaction of the laminar flow with the air curtain, and the laminar flow moves uniformly. The air curtain eliminates the need to install a bulky exhaust system around the entire perimeter of the room, instead of installing a traditional hood in the walls, as is customary in operating rooms.
The air curtain protects the area directly around the surgical personnel and table, preventing contaminated particles from returning to the primary air stream.
After designing an air curtain, the question arises as to what level of disinfection can be achieved during its operation. A poorly designed air curtain will be no more effective than a traditional laminar flow system. A design mistake may be high air speed, since such a curtain will “pull” the laminar flow too quickly, that is, even before it reaches the operating floor. Flow behavior may not be controlled and there may be a risk of contaminated particles leaking into the operating area from floor level. Likewise, an air curtain with a low suction speed cannot effectively block laminar flow and may be drawn into it. In this case, the air condition of the room will be the same as when using only a laminar air supply device. When designing, it is important to correctly determine the speed range and select the appropriate system. This directly affects the calculation of disinfection characteristics.
Despite the obvious advantages of air curtains, they should not be used blindly. The sterile airflow created by air curtains during surgery is not always required. The need to ensure the level of air disinfection should be decided together with technologists, whose role in this case should be surgeons involved in specific operations.
Vertical laminar flow can behave unpredictably depending on its operating conditions. Laminar flow panels used in clean production areas generally cannot provide the required level of disinfection in operating rooms. Air curtain systems help correct the movement pattern of vertical laminar flows. Air curtains are the optimal solution to the problem of bacteriological control of the air environment in operating rooms, especially during long surgical operations and patients with a compromised immune system, for whom airborne infections pose a particular risk.
The article was prepared by A. P. Borisoglebskaya using materials from the ASHRAE journal.
“Clean” rooms are intended for patients who need isolation from an unfavorable environment, with weakened immunity, when treating large wound surfaces, during medical procedures that require compliance with special air cleanliness indicators, i.e. the countable concentration of aerosol particles and the number of microorganisms in the air are maintained within certain limits.
Such premises can be equipped with: operating rooms, pre- and postoperative wards, burn departments, intensive care wards, boxes for infectious patients, microbiological, virological or other medical laboratories, pharmaceutical production premises and many other medical premises.
Currently, cleanliness technology in medical institutions has become an integral part of civilized healthcare and is the key to the success of the entire treatment process.
Cleanroom technology
Product quality and applicable standards for microelectronics, optics and pharmaceutical production depend on the purity class prevailing in each industry.
Suspended floors are often used. The empty space under the floor can be used to provide air circulation and accommodate pipes and cables, depending on the design of the room.
Optimal production conditions can only be created using high-precision technology. This technology includes efficient air conditioning and filtration.
However, one of the main factors determining the effectiveness of a cleanroom is the quality of the ceiling, walls, and floors from which the room is constructed. Depending on the cleanliness class, a clean ceiling using filters for laminar flow is used (cleanliness class = 10000).
Walls must separate the cleanroom area from other production and office premises (external adjacent walls), and at the same time separate rooms with different cleanliness classes. Different air cleanliness requirements include different operating parameters.
Interior partition walls must be easily adaptable to changing production requirements (semiconductor manufacturing cycles change every 3-4 years) in a cleanroom environment.
From the very beginning, cleanroom technology has developed in the USA along with computer technology. Since then, cleanrooms have been divided into cleanliness classes. Thus, English terminology is used in cleanroom technology.
Clean room classes.
| Class | Particle size (measured in 28L of air with a micrometer) | ||||
|---|---|---|---|---|---|
| 0.1 | 0.2 | 0.3 | 0.5 | 5.0 | |
| 1 | 35 | 7.5 | 3 | 1 | NP |
| 10 | 350 | 75 | 30 | 10 | NP |
| 100 | NP | 750 | 300 | 100 | NP |
| 1000 | NP | NP | NP | 1000 | 7 |
| 10000 | NP | NP | NP | 10000 | 70 |
| 100000 | NP | NP | NP | 100000 | 700 |
(NP - not applicable)
According to US Federal Standard 209 d
According to VDI 2083
The US Federal Standard is today the basis for defining technical requirements. VDI guidance is used less frequently.