A mercury bactericidal lamp is a sealed glass tube filled with mercury vapor. Under influence electric field An electric discharge passes through the gas. As a result, ultraviolet radiation is generated in the tube, which is used to disinfect air and surfaces in the room. Ultraviolet rays have a detrimental effect on the DNA structure of bacteria, microbes, viruses, fungi, effectively destroying pathogenic flora.
Ultraviolet radiation with a wavelength of less than 200 nm also ionizes oxygen contained in the air. As a result, ozone is formed, which is toxic in large quantities for living organisms. To prevent this effect, special uviol glass is used to manufacture the housings of bactericidal lamps, transmitting waves with a length of 205–315 nm and absorbing shorter radiation. In addition, the body can be made of quartz glass coated with a special protective layer. Ozone is also formed during the operation of such bactericidal lamps, but in small quantities that are safe for health. But it’s still better to leave the room while they’re working.
Quartz glass lamps that ozone the air are commonly called quartz ultraviolet lamps. Lamps made of uviol glass or quartz glass coated with a special protective layer are called bactericidal lamps
Nail extension using a UV lamp
- More details
The main disadvantage of mercury bactericidal lamps is the risk of contamination of the environment with mercury vapor if the bulb is damaged or disposed of.
Xenon germicidal lamp
Xenon device bactericidal lamp no different from mercury. In addition, the glass flask is filled with the inert gas xenon, which is safe for the environment. The bactericidal activity of these lamps is higher, but their service life is shorter.
The main disadvantage of xenon lamps is the need for complex, expensive equipment for their operation.
Application of germicidal lamps
Germicidal lamps are included in stationary and mobile irradiators. Stationary ones are usually used in medical institutions, and mobile ones can also be used at home to disinfect each room, as well as furniture, beds, and plumbing fixtures.
Special bactericidal irradiators for water disinfection are also produced. They are installed in water supply units and purify water from microorganisms.
Target:
Conditions: quartzing during current cleaning is carried out for 30 minutes, with spring cleaning-2 hours.
Indications:
Equipment:
gloves;
disinfectant solution;
alcohol 70%;
cotton swab, rags.
bactericidal lamp OBN;
workwear;
Execution order:
The device is designed for disinfecting indoor air.
Before connecting the device to the network, make sure that the power cord is not damaged.
Plug in the power cord for a certain period of time (for current cleaning for 30 minutes, for general cleaning for 2 hours).
It is forbidden to enter the room when the bactericidal lamp is turned on; entry is allowed 30 minutes after the lamp is turned off and aired.
The bactericidal lamp is replaced after 8000 hours of operation.
The operation of the bactericidal lamp is recorded in the Quartz Treatment Logbook.
The external finish of the device can be wet sanitization 0.1% Javel-Solid solution (solichlor, deochlor), twice with an interval of 15 minutes.
Wipe the bactericidal lamp with a gauze swab moistened with ethyl alcohol once a week.
Sanitation and cleaning of the device is carried out after disconnecting from the network.
Do not allow liquid to get inside the bactericidal lamp!
Unshielded mobile bactericidal irradiators are installed at a power rate of 2.0 - 2.5 watts (hereinafter referred to as W) per cubic meter (hereinafter referred to as m3) of room.
Shielded bactericidal irradiators with a power of 1.0 W per 1 m3 of room are installed at a height of 1.8 - 2.0 m from the floor, provided that the radiation is not directed towards people in the room.
In rooms with intense continuous load, ultraviolet recirculators are installed.
Troubleshooting the germicidal lamp is carried out by a medical equipment maintenance engineer.
Germicidal lamps belong to class “G” according to the unified classification of medical waste.
Target: Collection and temporary storage of used lamps is carried out in a separate room.
Conditions: 9.3 Algorithm “Carrying out routine cleaning in a hospital, clinic, laboratory, laundry, catering unit and temporary storage warehouse for medical waste of class “b” and “c”” prevention of nosocomial infection..
Indications: carrying out
Equipment:
disinfectants and detergents;
bactericidal lamp or recirculator.
current cleaning
measuring containers;
workwear;
safety shoes;
gloves;
Execution order:
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Event. |
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In the operating unit, in the department of anesthesiology, resuscitation, intensive care, in the sterile blocks of the central sterilization department and bacteriological laboratory, in the section room and in the laboratory of the pathology department current wet cleaning carried out 2 times a day using disinfectants(solution concentration as for general cleaning): 0.1% Javel-Solid = 7 tablets per 10 liters of water or 0.1% deochlor = 7 tablets, 0.1% Soliclor=7 tablets, 1.0% aldazan=80 ml to 8 liters of water, 2.5% defect = 250 ml to 10 liters of water, 2.0% dolbak = 200 ml to 10 l of water, 0.2% lysorine = 20 ml to 10 liters of water, 0.2% dezosept = 20 ml to 10 liters of water, 0.1% septalite=10 ml to 10 liters of water, 0.032% septalite DCC = 2 tablets per 10 liters of water. |
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Routine wet cleaning is carried out in other rooms, wards, offices, laundry and in the catering department of the branch carried out 2 times a day using disinfectants in a concentration of 1 tablet per 10 liters of water. |
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Wet cleaning of all surfaces is carried out: window sill, bed, bedside table, cabinets, tables, floor, doors, door handles, sinks and taps, water and sewer pipes. |
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Quartzization of a room or office with a bactericidal lamp or recirculator for 30 minutes. Hang a sign on the door “Attention, the bactericidal irradiator is on!”; Record the time in the quartzing log and in the general cleaning log. |
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Ventilate the room for 15-30 minutes depending on the season. |
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IN summer period, from June 1 to September 1 annually, the concentration of the working solution of the disinfectant is increased (for example: 2 Soliclor tablets per 10 liters of water) in order to prevent intestinal infections. |
I APPROVED
Head of the Department of Preventive Medicine of the Ministry of Health Industry of the Russian Federation R.I. Khalitov N 11-16/03-06 February 28, 1995
The guidelines were prepared by a team of authors from a number of organizations: Research Institute of Preventive Toxicology and Disinfection (M.G. Shandala, Academician of the Russian Academy of Medical Sciences - head of development, V.G. Yuzbashev, Candidate of Medical Sciences - head of the medical group), Research Institute "Zenith" (A L.Vasserman, candidate of technical sciences - head of the engineering group), Research Institute of Hygiene named after. F.F. Erisman (V.V. Vlodavets, Doctor of Medical Sciences), Scientific Research Institute of Medical Instrumentation (V.I. Eliseev, engineer), Scientific Research Lighting Institute (V.G. Ignatiev, Candidate of Technical Sciences) , Research Institute of Building Physics (V.M. Karachev, Candidate of Technical Sciences), Research Institute of General and Municipal Hygiene named after. A.N. Sysina (Skobareva, Candidate of Medical Sciences), Information and Analytical Center of the State Committee for Sanitary and Epidemiological Supervision of the Russian Federation (M.K. Nedogibchenko, medical doctor, N.E. Strelyaeva, epidemiologist).
INTRODUCTION
INTRODUCTION
The fight against infectious diseases has always been considered urgent task. One of the ways to successfully solve this problem is to widely use bactericidal lamps. More than 40 years have passed since the first document on the use of bactericidal lamps appeared in our country. Over the past period, the range of bactericidal lamps and irradiation devices has been significantly updated, numerous microbiological studies of the values of bactericidal exposures (doses) have been carried out to achieve the required level of bactericidal effectiveness with various types microorganisms when irradiated with radiation with a wavelength of 254 nm, and industrial samples of bactericidal irradiators have been developed.
Deciding to release a new edition methodological instructions, the team of authors was guided by the goal of using the accumulated experience in the use of bactericidal lamps and creating a document that reflects modern requirements and makes it possible to significantly expand the scope of their use.
Of the numerous areas of application of bactericidal lamps, the guidelines cover only the disinfection of air and surfaces in premises, as one of the most effective methods fight against pathogenic microorganisms. It is important to note that the use of bactericidal lamps requires strict implementation of safety measures that exclude harmful effects per person ultraviolet radiation, ozone and mercury vapor.
The guidelines are intended for workers of medical institutions and sanitary and epidemiological supervision bodies, as well as persons involved in the design and operation of irradiation facilities.
Guidelines are the basis for drawing up job descriptions for the maintenance of bactericidal installations by middle and junior medical and technical personnel.
They are advisory in nature and will allow you to comply at a higher level with the requirements of existing regulatory documents governing sanitary rules on the maintenance of various medical, children's, domestic and industrial premises equipped with irradiation installations with bactericidal lamps.
Users of bactericidal irradiators should take into account that UV radiation cannot replace sanitary and anti-epidemic measures, but only supplement them as the final stage of room treatment.
1. BACTERICIDAL EFFECT OF UV RADIATION
Ultraviolet radiation is known to have a wide range of effects on microorganisms, including bacteria, viruses, spores and fungi. However, due to established practice, this phenomenon is called a bactericidal effect, associated with irreversible damage to the DNA of microorganisms and leading to the death of all types of microorganisms. Spectral composition ultraviolet radiation, causing a bactericidal effect, lies in the wavelength range 205-315 nm. The dependence of bactericidal efficiency in relative units on the radiation wavelength is shown in the form of a curve in Fig. 1 and Table 1.
Fig.1. Relative spectral bactericidal efficiency curve
Fig.1. Relative spectral bactericidal efficiency curve
Table 1
According to these data, the maximum bactericidal effect occurs at a wavelength of 265 nm according to recent publications (4, 5), and not 254 nm, as previously thought (15). In accordance with this, in the adopted system of effective units that evaluate the parameters of ultraviolet radiation, the unit of bactericidal flux is taken to be a radiation flux with a wavelength of 265 nm, a power of one watt, and not a wavelength of 254 nm, with a power of one bact. The transition coefficient between these systems of units for the maximum bactericidal effect is 0.86, i.e. 1 bakt = 0.86 Watt.
The bactericidal flux of an ultraviolet radiation source is estimated by the ratio:
where is the spectral bactericidal efficiency in relative units;
- spectral radiation flux density, W/nm;
- radiation wavelength, nm.
Then other quantities and units can be determined using the following expressions.
Energy of bactericidal radiation:
where is the radiation exposure time, s.
Bactericidal irradiation:
where is the area of the irradiated surface, m.
Bactericidal exposure (in photobiology called dose):
Volume density of bactericidal energy:
where is the volume of irradiated air, m.
Microorganisms belong to cumulative photobiological receptors, therefore bactericidal efficiency should be proportional to the product of irradiation and time, i.e. determined by dose. However, the nonlinear characteristic of the photobiological receiver limits the possibility of wide variations in irradiation and time values with the same bactericidal efficiency. Within the permissible error, you can change the ratio of irradiation and time in the range of 5-10-fold variations.
The quantitative assessment of the bactericidal effect is characterized by the ratio of the number of dead microorganisms to their initial number and is estimated as a percentage.
The dose dependence of bactericidal effectiveness for microorganisms can be expressed using the equation
which reflects the well-known Weber-Fechner law, which establishes a connection between the physical impact on a biological object and its reaction. This equation can be transformed to the form
It allows you to determine the required dose value if you set the required level of bactericidal effectiveness.
Table 2 shows the experimental values of doses and bactericidal effectiveness for some types of microorganisms when irradiated with radiation with a wavelength of 254 nm and the values of the auxiliary coefficients "" and "" in the above equations.
table 2
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Types of microorganisms |
Doses, J/m, with bactericidal effectiveness, % |
The meaning of auxiliary coefficients |
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Bacteria |
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Staphylococcus aureus (Staphylococcus aureus) |
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Staph. epidermidis (epidermal staphylococcus) |
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Streptococcus-haemoliticus (hemolytic streptococcus) |
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Str. viridans (viridans streptococcus) |
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Corynebakterium diphteria (diphtheria bacillus) |
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Micobakterium tuberculosis (tuberculosis bacillus) |
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Sarcina flava (yellow sarcina) |
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Bacillus subtilis (bacillus subtilis spores) |
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Escherichia coli (Escherichia coli) |
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Salmonella typhi (typhoid bacillus) |
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Shigella (dysentery bacillus) |
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Salmonella enteritidis (salmonella enteritidis) |
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Salmonella typhimurium (Salmonella murine typhus) |
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Pseudomonas aeruginosa (Pseudomonas aeruginosa) |
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Enterococcus (enterococcus) Viruses |
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Influenza virus |
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Bacteriophage Escherichia coli |
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Yeast mushrooms |
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Yeast-like fungi (genus Candida) |
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Molds |
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2. BACTERICIDAL LAMPS
Electrical radiation sources, the spectrum of which contains radiation in the wavelength range 205-315 nm, intended for disinfection purposes, are called bactericidal lamps. Greatest distribution due to highly efficient conversion electrical energy, received mercury discharge lamps low pressure, in which, during an electrical discharge in an argon-mercury vapor-gas mixture, more than 60% turns into emission of the 253.7 nm line. High pressure mercury lamps are not recommended for wide application due to low efficiency, because their share of radiation in the specified range is no more than 10%, and their service life is approximately 10 times less than that of low-pressure mercury lamps.
Along with the 253.7 nm line, which has a bactericidal effect, the emission spectrum of a low-pressure mercury discharge contains a 185 nm line, which, as a result of interaction with oxygen molecules, forms ozone in the air. In existing bactericidal lamps, the bulb is made of uviol glass, which reduces, but does not completely eliminate, the output of the 185 nm line, which is accompanied by the formation of ozone. The presence of ozone in the air can lead, at high concentrations, to dangerous consequences for human health, including fatal poisoning.
Recently, so-called bactericidal “ozone-free” lamps have been developed. For such lamps, due to the manufacture of the bulb from a special material (coated quartz glass) or its design, the output of the 185 nm line radiation is eliminated.
Structurally, bactericidal lamps are an extended cylindrical tube made of quartz or uviol glass. At both ends of the tube there are soldered legs with electrodes mounted on them, pinned on both sides with two-pin bases.
Germicidal lamps are powered by electrical network voltage 220 V, with frequency alternating current 50 Hz. The lamps are connected to the network through ballasts (ballasts), providing the necessary modes of ignition, combustion and normal operation lamps and suppress high-frequency electromagnetic vibrations generated by the lamp, which could cause adverse effects on sensitive electronic devices.
The ballasts are a separate unit mounted inside the irradiator.
Main technical and operational parameters of bactericidal lamps: spectral distribution of radiation flux in the wavelength range 205-315 nm; bactericidal flow, W; bactericidal output equal to the ratio of bactericidal flow to lamp power
Lamp power, W;
- lamp current, A;
- lamp voltage, V;
- rated mains voltage, V and alternating current frequency, Hz;
- useful service life (total burning time in hours before the main parameters that determine the feasibility of using the lamp go beyond the established limits, for example, a decrease in the radiation flux to a level below the standardized value (specified in the specifications).
A special feature of bactericidal lamps is the significant dependence of their electrical and emission parameters on fluctuations in network voltage. Figure 2 shows this dependence.
Fig.2. Dependence of lamp power P(l) and radiation flux Ф(l) on network voltage U(c)
Fig.2. Dependence of lamp power and radiation flux on mains voltage
As the network voltage increases, the service life of bactericidal lamps decreases. Thus, when the voltage increases by 20%, the service life decreases to 50%. When the mains voltage drops by more than 20%, the lamps begin to burn unsteadily and may even go out.
As the lamps operate, the radiation flux decreases. A particularly rapid drop in radiation flux is observed during the first tens of hours of combustion, which can reach 10%. With further combustion, the rate of decay of the radiation flux slows down. This process is illustrated by the graph in Fig. 3. The lifespan of the lamps is affected by the number of times they are switched on. Each switching on reduces total term lamp service for approximately 2 hours.
Fig.3. Decline in the radiation flux of the DRB 30-1 bactericidal lamp during combustion
Fig.3. Decline in the radiation flux of the DRB 30-1 bactericidal lamp during combustion
Ambient air temperature and its movement affect the radiation flux value of the lamps. This dependence is shown in Fig. 4. It should be noted that “ozone-free” lamps are practically insensitive to changes in ambient temperature. As the ambient temperature decreases, it becomes more difficult to ignite the lamps, and the sputtering of the electrodes also increases, which leads to a reduction in service life. At temperatures below 10°C, a significant number of lamps may not light up. This effect is enhanced at reduced network voltage.
Fig.4. Dependence of the lamp radiation flux on the ambient temperature (in calm air)
Fig.4. Dependence of the lamp radiation flux on the ambient temperature (in calm air)
The electrical parameters of bactericidal lamps are almost identical to those of conventional fluorescent lamps, so they can be connected to an alternating current network with ballasts designed for fluorescent lamps of similar power.
Table 3 shows the main parameters of modern low-pressure bactericidal lamps and ballasts.
Table 3
MAIN TECHNICAL PARAMETERS OF BACTERICIDAL LOW PRESSURE MERCURY LAMPS
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Parameter meaning |
Service life, hour |
Dimensions: |
Bulb material |
Note: |
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Lamp type |
Power- |
Voltage |
Current strength, , A |
Bacteria |
diameter, mm |
length, mm |
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uviol glass |
Ozone lamps* |
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quartz glass |
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uviol glass |
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quartz coated |
ozone-free lamps |
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DRB 3-8*** |
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* For “ozone” lamps, the ozone content in the air is not standardized in the specifications; for “ozone-free” lamps it is normalized.
** - E-lamps with improved environmental parameters;
*** - -shaped.
Based on the type of current-limiting element, existing ballasts are divided into two groups: electromagnetic and electronic. According to the ignition method, ballasts are divided into starter and non-starter, and according to the number of connected lamps - into single-lamp, two-lamp and multi-lamp.
Some schemes for switching on low-pressure bactericidal mercury lamps are given in Appendix 1.
3 BACTERICIDAL IRRADIENTS
A bactericidal irradiator (BI) is a device containing a bactericidal lamp as a radiation source and intended for disinfecting the air environment or surfaces in a room.
The BO consists of a housing on which a bactericidal lamp, ballast, reflector, and fixtures for fastening and installation are installed. The design of the BO must ensure compliance with electrical, fire and mechanical safety conditions, as well as other requirements that exclude harmful effects on environment or person. According to the conditions of placement, bactericidal irradiators are divided into irradiators intended for use in stationary premises and installed on vehicles, for example, in ambulances. Based on their location, BOs are divided into ceiling-mounted, suspended, wall-mounted and mobile. According to their design, they can be open type, closed type and combined. Open-type irradiators are intended for irradiation of the air environment and surfaces in rooms with a direct bactericidal flow in the absence of people by redistributing the lamp radiation within large solid angles up to 4. Closed-type bactericidal irradiators are intended for irradiation of air and surfaces in rooms with a direct and reflected bactericidal flow in the absence , and in the presence of people, the reflector of which should direct the bactericidal flow of the lamp into the upper hemisphere so that no rays, either directly from the lamp or reflected from parts of the irradiator, are directed at an angle less than 5° upward from the horizontal plane passing through the lamp. Bactericidal irradiators of the combined type combine the functions of open and closed type BOs. They have different separately switched lamps for direct and reflected irradiation, or a movable reflector that allows the use of a bactericidal flow for direct (in the absence of people) or reflected (in the presence of people) irradiation of the room.
One of the types of closed BO are recirculators, designed to disinfect air by passing it through closed chamber, the internal volume of which is irradiated by radiation from bactericidal lamps.
The speed of air flow is provided either by natural convection or forced by a fan.
Mobile BOs, as a rule, are open-type irradiators.
Bactericidal irradiators have a number of parameters and characteristics that make it possible to evaluate them consumer properties and determine the most effective area of application. These include:
- type of irradiator, purpose and design;
- type of bactericidal lamp and number of lamps;
- mains voltage (V) and alternating current frequency (Hz);
- consumed current-voltage power (V·A), equal to the product of the network current (A) by the network voltage (V);
- consumed active power(W), equal to total power lamps and losses in ballasts;
- bactericidal flow (W) emitted by the irradiator in space;
- coefficient useful action(efficiency) equal to the ratio of the bactericidal flux of the irradiator to the total bactericidal flux of the lamps
Bactericidal irradiation (W/m) at a distance of 1 m from the irradiator;
- productivity (m/h), equal to the ratio of the volume of air (m) to the irradiation time (h) required to achieve a given level of bactericidal effectiveness (%) for a certain type of microorganism;
M/hour.
Table 4 shows the main technical specifications and characteristics of industrial bactericidal irradiators, and in Table 5 - radiative and economic parameters.
Table 4
MAIN TECHNICAL PARAMETERS AND CHARACTERISTICS OF BACTERICIDAL IRRADIENTS
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Designation |
The main purpose of disinfection |
Irradiator type |
Construct. execution |
Lamp type |
Number of lamps |
Consumption powerful |
Consumption Act. power, , W |
Note: |
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screen- |
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There is no disinfection of air in the interiors of ambulances. of people |
open |
sweat- |
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OBPe-450 |
There is no disinfection of indoor air. of people |
mobile |
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Disinfection of indoor air in the presence of or absent of people |
combination |
wall- |
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1In this case, you can repeat the purchase of the document using the button on the right. An error has occurred The payment was not completed due to technical error, cash from your account | |||||||||
Educational organizations often become hotbeds of viral diseases, and the peculiarities of their functioning contribute to the spread of infections. Among the factors contributing to the high risk of spread in educational organizations Diseases transmitted by airborne droplets include overcrowding of groups and classes, overcrowding in recreation areas, locker rooms, and insufficient knowledge of personal hygiene rules, which especially concerns primary school students and preschoolers.
There are often situations when one or two children with signs of the disease are enough for the infection to be transmitted by airborne droplets to other students in the class (group). That is why during periods of epidemic growth Special attention need to pay attention to organizing the morning filter when receiving children in kindergarten(school) in order to prevent a student with signs of illness from being in the group. When a sick person is identified, it is important to isolate him in time.
No less important for preventing the occurrence and spread of infections during the period of epidemic growth is the implementation of disinfection measures in educational and group rooms. In addition to the widely used chemical methods disinfection; currently, educational organizations also use the method of ultraviolet disinfection of premises. The article will discuss specifically the physical method of disinfection.
At ultravioletdisinfection premises the impact of irradiation on the structure of microorganisms in the air and on various surfaces, leads to a slowdown in their reproduction rates and extinction. Ultraviolet bactericidal irradiation of indoor air is carried out using ultraviolet bactericidal irradiators and installations, which are used to reduce the level of bacterial contamination and create conditions to prevent the spread of pathogens of infectious diseases.
Our information.According to clause 2.3 R 3.5.1904-04 “Use of ultraviolet bactericidal radiation for air disinfection in premises,” ultraviolet bactericidal installations should be used in premises with an increased risk of the spread of infectious agents: in medical and preventive, preschool, school, industrial and public organizations and other rooms with large crowds of people.
The use of ultraviolet equipment, according to the Moscow Department of Education, can significantly reduce the level of microbial contamination of the air in rooms with an increased risk of the spread of infectious agents in group, educational and other premises with large concentrations of children - canteens, assembly halls and gyms. Practice of using ultraviolet equipment in educational organizations in 2005-2010. showed a decrease in the incidence of acute respiratory infections viral infections(ARVI) among children by more than 30%.
Ultraviolet bactericidal irradiators
An ultraviolet bactericidal irradiator (hereinafter referred to as a bactericidal irradiator) is an electrical device consisting of an ultraviolet bactericidal lamp or lamps, a ballast, reflective fittings, parts for attaching lamps and connecting to the power supply network, as well as elements for suppressing electromagnetic interference in the radio frequency range. Bactericidal irradiators are divided into three groups: open, closed and combined.
U closed irradiators (recirculators), the bactericidal flow from the lamps located in a small closed space of the irradiator housing has no outlet to the outside. In this case, air disinfection is carried out in the process of pumping it through the ventilation holes on the housing using a fan. Such irradiators used to disinfect air in the presence of people .
U open irradiators, the direct bactericidal flow from lamps and reflector (or without it) covers a wide area in space. Combined The irradiators are equipped with two bactericidal lamps, separated by a screen in such a way that the flow from one lamp is directed outward to the lower zone of the room, and from the other to the upper zone. The lamps can be turned on together or separately. Open and combined irradiators can be used to disinfect a room only in the absence of people or during their short stay in the room .
In the presence of people with time restrictions, use method of indirect irradiation of premises. It is carried out using lamps suspended at a height of 1.8-2.0 m from the floor with a reflector facing upward so that the direct radiation flow falls into the upper zone of the room. The lower area of the room is protected from direct rays by a lamp reflector. The air passing through the upper zone of the room is actually exposed to direct irradiation. Ultraviolet rays reflected from the ceiling and upper part of the walls affect the lower zone of the room where people may be. Best degree reflection is achieved if the walls are painted in White color. And yet, the efficiency of air disinfection in the lower zone is practically zero, since the intensity of reflected radiation is 20-30 times less than direct radiation.
Germicidal irradiators can be mobile and stationary. The latter are usually mounted on the wall. Mobile irradiators are optimal solution for institutions where disinfection is not carried out simultaneously in all premises. In preschool educational organizations, a mobile irradiator can be located, for example, in a place where toys are stored. In schools it is more convenient to use stationary recirculators.
The main disadvantage of ultraviolet disinfection of air and surfaces is the lack of a prolonged effect. The advantage is that when using this method, harmful effects on humans and animals are excluded, which cannot be said about disinfection with chlorine-containing substances. In addition, bactericidal lamps, unlike quartz lamps, do not produce ozone during operation: the glass of the lamp filters out the ozone-forming spectral line. Their use is safe for the respiratory system, and rooms with continuously operating bactericidal lamps do not require mandatory ventilation.
For your information
In the most common low-pressure lamps, 86% of the radiation occurs at a wavelength of 254 nm, which is in good agreement with the peak of the bactericidal efficiency curve, i.e., the efficiency of ultraviolet absorption by DNA molecules.
Some features of the use of bactericidal irradiators in educational organizations
First of all, ultraviolet irradiation in educational organizations should be used to disinfect the air. Surfaces in kindergartens and schools are disinfected using disinfectants, but a bactericidal irradiator allows for additional treatment. It is important that the surfaces to be disinfected are clean and not cluttered with foreign objects. A special area of application of bactericidal irradiators in kindergartens is the disinfection of toys. The fact is that some types of toys ( Stuffed Toys big size, play structures from different types materials, etc.) cannot be processed chemicals, wash or disassemble into parts for disinfection individual elements. In this case, when carrying out ultraviolet disinfection of a room, large toys are placed in an open space, composite toys are disassembled as much as possible and the parts are laid out.
Rules for working withbactericidalirradiator
1. The operation of bactericidal irradiators must be carried out in strict accordance with the requirements specified in the passport and operating instructions.
2. Personnel who have not undergone the necessary training in the prescribed manner are not allowed to operate bactericidal installations, the conduct of which should be documented.
3. Closed-type irradiators (recirculators) should be placed indoors on the walls along the main air flows, in particular near heating devices, at a height of at least 1.5-2.0 m from the floor. The location of the recirculator must be accessible for processing.
4. Every week, the bactericidal irradiator lamp is wiped from all sides from dust and fatty deposits with a sterile gauze cloth. The presence of dust on the lamp reduces the effectiveness of air and surface disinfection by up to 50%. Wiping off dust should only be carried out when the bactericidal installation is disconnected from the network.
5. Normally, closed-type bactericidal irradiators do not emit ozone. But if the lamps malfunction or reach the end of their service life, the smell of ozone may occur in the room. In this case, you must immediately remove people from the room and thoroughly ventilate it until the ozone smell disappears.
6. All premises with bactericidal installations, operating or just being introduced, must have an act of their commissioning and a log of their registration and control.
Logbook for registration and control of ultraviolet bactericidal installation
According to Appendix 3 to R 3.5.1904-04, the registration and control log of an ultraviolet bactericidal installation is a document confirming its performance and operational safety. It must register all bactericidal installations in operation on the premises of the institution, as well as the results of control checks of the condition of the bactericidal irradiator. The magazine consists of two parts. Examples of the design of each of them in accordance with Appendix 3 to R 3.5.1904-04 are presented below.
Exposition
Unlike quartz lamps or open irradiators, the operating time of closed irradiators used in the presence of people is not limited. Bactericidal recirculators with irradiator lamps installed in them can safely operate for 8 hours a day. However, in practice, irradiators are turned on during the disinfection of surfaces and objects or immediately after it to achieve maximum effect disinfection during exposure.
Our dictionary
Volumetric bactericidal dose is the volumetric density of bactericidal radiation energy (the ratio of the energy of bactericidal radiation to the air volume of the irradiated environment).
For children's rooms game rooms, school classrooms, household premises public buildings with a large crowd of people during a long stay, the value of the volumetric bactericidal dose, ensuring the achievement of disinfection efficiency of up to 90, 95, 99.9% when irradiating microorganisms with radiation with a wavelength of 254 nm from a low-pressure mercury lamp, is 130 J/m 3 .
For premises of educational organizations indicator of microbial contamination in the air, i.e. the total content of microorganisms in 1 m 3 of air, is not regulated. However, it is normalized value b Acticidal (antimicrobial) effectiveness , reflecting the level of reduction in microbial contamination of the air or on the surface as a result of exposure to ultraviolet radiation, expressed as a percentage as the ratio of the number of dead microorganisms to their initial number before irradiation. For educational organizations, the bactericidal efficiency value should be at least 90%.
In conclusion, let us once again draw attention to the fact that the use of closed-type bactericidal irradiators in kindergartens and schools significantly reduces the risk of ARVI and other infections among adults and children, which is especially important during periods of epidemic surges. However, bactericidal effectiveness without compromising the safety of children and teaching staff can only be achieved with strict adherence to the rules for operating bactericidal installations.