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Ventilation in rooms such as the operating room is necessary to maintain hygienic conditions. Clean rooms are an environment where there are no microorganisms and harmful substances that adversely affect human health. It is in these conditions that medicines are manufactured, patients are operated on and treated, blood is transfused, watches and optics are produced, microelectronics are assembled, and food is processed. Ensuring and maintaining sanitary and hygienic conditions, as well as a controlled climate in such premises are especially important important role. A favorable microclimate is achieved using ventilation systems. However, ventilation in clean rooms should not be standard. The choice of such a climate control device depends on the functional load, size and cleanliness class. The latter is certain requirements by the level of particles and impurities in the air.

Clean rooms are divided into three classes, differing in the number of microorganisms per unit volume:

Ventilation in clean rooms reduces the spread of microorganisms, supplies clean air, prevents the entry of contaminated air, and controls temperature and humidity levels. Most effective system air distribution is considered to be the installation of filters along the entire perimeter of the ceiling area. As a rule, cleanrooms are divided into four main types, each of which has different air flow:

• Clean room with multi-directional air flow. This can be achieved using conventional ventilation, which features the classic method of supplying air through air distributors.
• Clean room with unidirectional air flow. This type involves filing clean air using a filter system while maintaining the direction of movement. This flow is also called “laminar”, which ensures great value air exchanges at low speed (0.3 m/sec throughout the entire zone).
• Clean room with mixed flow. In areas where the product is exposed to contamination, a laboratory cabinet with unidirectional flow is installed.

Supply and exhaust ventilation systems for clean rooms

Cleanrooms include those where microelectronics are assembled, medicines are manufactured, and watches are produced. The microclimate in these rooms must be stable
Supply ventilation of a clean room supplies clean air into the room with given parameters for a favorable microclimate. This ventilation system processes and purifies the air before supply, regulates the level of humidity and temperature. Exhaust ventilation of a clean room removes contaminated air, provides the necessary air exchange rate, and maintains negative pressure in certain areas of the room.

The specialists of our company “Vent-m” have the necessary knowledge and practical skills to install ventilation in clean rooms. Taking into account all the features of such premises, they choose a certain type of device and install it at a high level of quality.

When designing ventilation systems for clean rooms used in the production of microelectronics, laboratories of medical institutions, operating rooms, aseptic wards and departments, rooms with a 3D printer, etc. - it is necessary to follow SNiP standards and GOST requirements, based on the customer’s recommendations and the required cleanliness class.

Sanitary standards, technical specifications, manuals and installation rules

• Stages of ventilation design
• Hospital ventilation systems
• Reliable ventilation of medical laboratories

The main rule of a modern designer of “clean” ventilation is an individual approach, excluding standard solutions. The basis for organizing proper air exchange in “clean” rooms are the following requirements and standards:

• SNiP 41-01-2003(8), which determine the balance of supply and exhaust ventilation, taking into account the presence or absence of a transfer airlock (vestibule, window);
• GOST ISO 14644-1-2002, classifying 9 types of room cleanliness, depending on the size and number of particles suspended in the air.

Purpose and classification of “clean” ventilation systems

Modern design recommendations are based on the mandatory requirement that the air prepared for the premises of medical institutions, laboratories, operating rooms and aseptic departments must be sterile. The implementation of such a project requires the installation of industrial antibacterial filters with a high lower threshold for filtration of harmful particles and microorganisms - HEPA and ULPA.

In the production of microelectronics, zonal ventilation of unidirectional and mixed types is used. The cleanliness class of such an object varies depending on the area - working, technological (maintenance), service.

For a clean room with a 3D printer it is planned separate room. Maintaining the required cleanliness is ensured by the installation additional devices air conditioning, transfer window or airlock.

Air exchange in complexes with “clean” rooms

In production, warehouse, office, medical complexes clean rooms and rooms, a modular ventilation scheme is used, including air distributors, air filters, transfer gateways, boxes and windows, units of monitoring and automation systems. Finishing ventilation equipment and air conditioning channels are made with special sealants. The construction of such objects is carried out from special materials - plastic, gypsum metal wall panels, sandwich panels for suspended ceilings, rounding profiles of skirting boards, hermetic doors, windows and lamps, floors with sticky mats. To minimize air pollution, select metal furniture. Clothes, shoes, and technological equipment are stored in isolated lockers and boxes.

An important point in the design process of clean complexes is good manufacturing practice - the GMP standard, which allows not only to calculate the cleanliness class for the technological environment of a room or premises, but also to responsibly install air conditioning and ventilation systems. A facility for the production of microelectronics, pharmaceuticals, medical equipment, food, etc. must not only undergo certification of climate control equipment, but also be subject to constant monitoring of its operation, including service maintenance, routine repairs, disinfection and cleaning.

Climate project of the medical center

When executing design work At the Moscow Doctor medical center, our company’s specialists performed the calculation, supply, and installation of ventilation and air conditioning systems for its clean rooms. GOST requirements were met in accordance with ISO-2002, taking into account ISO class 5 cleanliness for suspended particles.

The air supply was carried out by an intake device with industrial. SHUFT fan, which passes air through a multi-stage system with a HEPA filter. Heat recovery and air recirculation in the clinic's aseptic clean room were carried out with a Funke heat exchanger. The required degree of sterility was maintained by a transfer lock.

At the customer's request, 2 operating modes of ventilation equipment were prepared. The clean ventilation mode supplied air through a separate automation unit that was not connected to other rooms of the medical facility building. The second mode allowed control of air exchange from the control panel, for emergency notification purposes, in the absence of personnel in the building.

The purpose of the designed aseptic department in the medical center is an operating room and sterilization room. Procedures for the treatment of dermatitis were to be carried out in a clean room.

Perioral dermatitis

This type of dermatitis is a rare skin disease. Most often, this skin disease affects representatives of the fair half of humanity aged 20 to 40 years. Dermatologists sometimes call perioral dermatitis perioral dermatitis or perioral dermatitis. The last disease comes from the name of the place where it is located.

Symptoms of perioral dermatitis

Very often, the onset of perioral dermatitis is expressed by several pimples on the skin in the mouth area. Patients complain that the use of conventional hygiene products that prevent acne, it only gets worse and the area of ​​the affected area increases. You should immediately contact a medical center that specializes in skin diseases if you experience the following symptoms:

The skin on the chin and around the mouth is covered with a pronounced rash. Red rash, itching and burning of the affected skin. The skin seems to be tightened.

Pimples around the mouth do not occupy the entire area of ​​the skin, but some areas. That is, they are located in localized areas.

Sometimes it is accompanied by pimples containing heads filled with clear liquid. When these heads burst, the liquid they contain leaks onto the skin. The red rash turns into ulcers over time.

The affected areas of the skin are covered with transparent scales, which periodically peel off from the surface and fall off. Similar symptoms may occur in other diseases of the human body.

Causes of perioral skin disease

Like any dermatitis, this one is caused by a decrease in protective function skin. The following factors can provoke disruptions in the skin’s immune system:

• Failure in the body's hormonal background (endocrine system).
• Reduced cellular immunity of skin tissues.
• Sudden climate change and prolonged exposure to direct skin sun rays. Ultraviolet radiation is bad for the skin.
• Allergies of a bacterial nature.
• Allergic reactions to cosmetics and hygiene chemicals.

Skin reactions may occur from the use of allergenic medical supplies. Before starting treatment for any disease, the doctor must make sure that the patient is not allergic to the constituent elements of the drug.

• Genetic predisposition to allergies.
• Rhinitis, asthma.
• Gynecological problems that cause a woman's hormonal imbalance.
• Increased sensitivity of the skin in the mouth and chin area.
• Dental dentures, cleaning pastes, especially fluoride-containing ones.
• Problems with the digestive system, especially in the gastrointestinal tract.
• Stressful situations, depressive states, that is, all situations that lead to disorders of the nervous system of the human body.

The cost of designing clean room ventilation is from 199 rubles. for 1 m2

“Clean” prices for turnkey clean room ventilation

The climate control company StroyEngineering LLC will carry out projects for facilities catering(canteens, cafes, restaurants), production workshops(welding places, painting booths), workshops (jewelry, microelectronics), healthcare institutions (medical and preventive complexes, pharmacies, swimming pools, maternity hospitals, laboratories), office, server, residential, warehouse and retail premises ( shopping centers, shops) - in accordance with modern requirements, according to GOST parameters and SNiP standards.

Requires high-tech, convenient and practical scheme air purification for private and public medical centers, rented and “own” clean rooms in Moscow and the region - with dispatching? We offer honest and “clean” prices (without markups) for design and installation work with subsequent service for construction and repair organizations, owners of sports clubs, tenants, healthcare institutions and catering establishments!

Our organization’s services include the selection and installation of specialized equipment for airlocks and transfer windows. Industrial air conditioners, filters, air distributors, control units, recuperators, etc. will create optimal conditions for performing any tasks at your “clean” facilities.

Development and implementation of clean room ventilation projects

• An example of installing ventilation in a clinic according to SanPiN
• Ventilation standards for ultrasound, x-ray, physiotherapy, massage rooms
• Ventilation requirements for dentistry with an X-ray machine
• SNiP pharmacy ventilation
• Example of ventilation of a sports hall with a gym and a swimming pool
• Dry cleaning ventilation project at a consumer services enterprise

Previous material - ventilation of residential premises!

Without clean rooms it is impossible to imagine the production of electronic chips, the pharmaceutical industry, effective treatment of patients, and research in different industries medicine and cooking. A room in which the number of aerosol particles and the number of bacteria in the air is maintained at an acceptable level is considered clean. There are nine classes of cleanrooms depending on the concentration of dust and bacteria in the air. They are enshrined in GOST ISO 14644-1-2000, which is based on the international standard ISO 14644-1-99 “Clean rooms and associated controlled environments”.

As part of ordinary air (which we breathe in everyday life) located large number impurities (smog, dust, pollen, viruses, fungi). The listed impurities are unacceptable for clean rooms, as they negatively affect the work. Therefore, the creation of ventilation and air conditioning systems in clean rooms is an essential component of ensuring a suitable microclimate.

Features of designing a ventilation system for clean rooms

Design and installation of ventilation and air conditioning systems for clean rooms requires skills in working with special equipment, as well as knowledge of the standards and requirements for clean rooms.

There are three schemes for organizing air exchange in clean rooms:

• all air flows move in parallel;
• disordered direction - the supply of clean air occurs in different sides;
• mixed direction - observed in large rooms, when in one part the air moves in parallel, and in the other part - in a disorderly manner.

Depending on the size of the room and the location of the work area, the optimal design of the ventilation system is chosen, but the most optimal solution is ventilation with a unidirectional flow of clean air.

For clean rooms only supply and exhaust system ventilation and air conditioning. Its essence is as follows: a flow of clean air is supplied from above under pressure at a certain speed, which “squeezes out” the polluted air in the room down to the air intakes.

The cooled air is supplied at a low speed, usually at top part rooms (approximately 1/4 of the room volume) through ceiling panels. It seems to flow around the space, lowering the dust down towards the hood, while creating a minimal level of irritation. With such ventilation, drafts and whirlwinds of dust that settle on the floor do not appear. In addition, the supplied air is pre-conditioned to the required temperature and humidity.

The basis of the ventilation and air conditioning system is a supply and exhaust unit with recirculation, consisting of the following elements:

1. frame;
2. filters;
3. humidifier;
4. heat exchangers;
5. fans.

   General diagram of the cleanroom ventilation system.
   

Special requirements are placed on filters. The filtration system consists of three groups of filters through which the air flow sequentially passes:

• coarse filter (first degree of filtration) - removes mechanical impurities from the air;
• fine filter (second degree of filtration) - removes bacteria and other microorganisms;
• HEPA and ULPA microfilter with absolute purification (removes 99.999995% of microorganisms).
  

Coarse and fine filters are located in the central air conditioner, and HEPA and ULPA filters are located directly in the air distributors.

HEPA and ULPA filters

Depending on the size of the room, air pressure, and method of placing furniture, the number and characteristics of air intakes and air distributors are determined.

There are a number of rules that need to be taken into account when designing exhaust ventilation for clean rooms:

1. It is necessary to maintain a positive air pressure imbalance in clean rooms. The pressure drop must be at least 10 Pa with the doors closed.
2. At the design stage, it is important to take into account the height of the ceilings. If they are higher than 2.7 m, then it is more rational to use the method of local ventilation of the workplace. In this case, a stream of clean air flows directly to the place where the person works.
3. For rooms up to 4.5 m instead of a raised floor, wall gratings are installed at a height of 0.6 m to 0.9 m . A directed stream of air envelops the room and moves towards the grilles, gradually displacing polluted air.
4. “Clean” rooms should be located near those rooms in which the level of cleanliness is as high as possible.
5. For the construction of clean rooms, exclusively environmentally friendly materials with high tightness are used, which will allow maintaining stable air circulation.
6. In clean rooms it is necessary to use HEPA filters and CAV regulators: the former provide high quality purification of the supplied air, and the latter determine the portion size of its supply.

Below are the most optimal ventilation and air conditioning systems for clean rooms.

A) Unidirectional flow is supplied through the ventilation grille.

B) Air is supplied in different directions due to diffusers located on the ceiling.

C) Unidirectional flow enters the room through a perforated panel on the ceiling.

D) Air is supplied directly to the work area through an air distributor located on the ceiling.

D) The flow of clean air moves in opposite directions due to the equipment of ring air hoses.

Cleanroom ventilation requirements

The following requirements apply to ventilation systems for clean rooms:

• Reducing quantity harmful impurities and bacteria, which includes a number of such actions: removing polluted air and supplying clean air, protecting the workplace from harmful impurities and microorganisms, blocking the flow of air from other rooms.
• Providing the following air parameters: temperature, mobility, humidity, concentration of harmful impurities.
• Prevents the accumulation of static electricity.

In addition, the cleanroom ventilation system is aimed at “blocking” the occurrence of such effects:

• periodic turbulent eddies;
• dust formation in some areas;
• temperature deviation from the norm;
• different levels of humidity in different areas of the serviced premises.

Air exchange requirements

Air exchange in a room is determined through air mobility, which is measured in m/s. Only for sterile rooms in the pharmaceutical industry is there a clear definition of the required air exchange - 0.46 m/s ±0.1 m/s (FDA, USA). Recommended air mobility standards for clean rooms range from 0.35 to 0.52 m/s±20%.

The presence of windows also affects air exchange. So, in a sealed room without windows, the air performance should be 20% higher than the hood, and in a room with windows - 20%.

GOST R 56190-2014

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

Clean rooms

Energy Saving Methods

Cleanrooms. Energy efficiency

OKS 13.040.01;
19.020
OKP 63 1000
94 1000

Date of introduction 2015-12-01

Preface

1 DEVELOPED by the All-Russian public organization"Association of Micropollution Control Engineers" (ASINCOM) with the participation of the Open Joint Stock Company "Research Center for Control and Diagnostics" technical systems" (JSC "SRC KD")

2 INTRODUCED by the Technical Committee for Standardization TC 184 “Ensuring Industrial Cleanliness”

3 APPROVED AND ENTERED INTO EFFECT by Order of the Federal Agency for Technical Regulation and Metrology dated October 24, 2014 N 1427-st

4 INTRODUCED FOR THE FIRST TIME


The rules for the application of this standard are established in GOST R 1.0-2012 (section 8). Information about changes to this standard is published in the annual (as of January 1 of the current year) information index "National Standards", and the official text of changes and amendments is published in the monthly information index "National Standards". In case of revision (replacement) or cancellation of this standard, the corresponding notice will be published in the next issue of the information index "National Standards". Relevant information, notices and texts are also posted in information system public use- on the official website of the Federal Agency for technical regulation and metrology on the Internet (gost.ru)

Introduction

Introduction

Cleanrooms are widely used in electronics, instrumentation, pharmaceutical, food and other industries, medical devices, hospitals, etc. They have become an integral part of many modern processes and a means of protecting people, materials and products from contamination.

At the same time, clean rooms require significant energy consumption, mainly for ventilation and air conditioning, which can exceed the energy consumption in ordinary rooms by tens of times. This is caused by high air exchange rates and, as a consequence, significant needs for heating, cooling, humidification and dehumidification of air.

The current practice of creating clean rooms is focused on ensuring specified cleanliness classes without due attention to the tasks of saving energy resources.

Maintaining a given cleanliness in a room is a difficult and complex task. It is necessary to have precise knowledge of the particle emission characteristics and, based on them, to perform calculations of air flow and air exchange rates, which is not always possible. The concentration of particles in the air is probabilistic and depends on many factors: human influence, process, equipment, materials and products, which are difficult to estimate accurately, especially at the design stage. Because of this, design decisions are made with a large margin in order to guarantee the required cleanliness class during certification and operation.

A well-designed and constructed cleanroom has a margin of cleanliness. The current practice of certification and operation of clean rooms does not take this reserve into account, which leads to unnecessary energy consumption.

Another reason for excessively high air exchange rates included in projects is the application of regulatory requirements that do not apply to this facility. For example, Appendix 1 to GOST R 52249-2009 “Rules for the production and quality control of medicinal products” (GMP) establishes that the recovery time of a clean room during the production of sterile medicinal products should not exceed 15-20 minutes. To meet this requirement, the air exchange rate can significantly exceed the values ​​necessary to ensure the cleanliness class in steady state.

Extension of requirements for the production of sterile medicines to non-sterile drugs and other products, including non-medical purposes, leads to significant waste of energy.

Guidance on energy savings in cleanrooms is given in UK standards BS 8568:2013* and Society of German Engineers VDI 2083 Part 4.2.
________________
* Access to international and foreign documents mentioned here and further in the text can be obtained by following the link to the website http://shop.cntd.ru. - Database manufacturer's note.


This standard provides requirements for determining the real power reserve at the stages of certification and operation based on the actual consumption of energy resources while guaranteeing compliance with a given cleanliness class. Energy savings should be provided not only at the design stage of cleanrooms, but also ensured during certification and operation.
________________

A.Fedotov. - "Saving energy in cleanrooms". Cleanroom Technology. London, August, 2014, pp.14-17 Fedotov A.E. "Energy saving in clean rooms" - "Cleanliness Technology" N 2/2014, pp. 5-12 Clean rooms. Ed. A.E. Fedotova. M., ASINKOM, 2003, 576 p.


When certifying and operating clean rooms, the actual emission of particles should be assessed and, based on this, the required air flow rate and air exchange rate should be determined, which may be significantly lower than the design values.

This standard provides a flexible approach to determining the air change rate, taking into account the actual release of particles and technological process.

1 Application area

This standard specifies methods for energy conservation in cleanrooms.

The standard is intended for use in the design, certification and operation of clean rooms in order to save energy resources. The standard takes into account the specifics of clean rooms and can be used in various industries (radio electronics, instrument making, pharmaceutical, medical, food, etc.).

The standard does not affect the requirements for ventilation and air conditioning established by regulatory and legal documents on the safety of working with pathogenic microorganisms, toxic, radioactive and other hazardous substances.

2 Normative references

This standard uses normative references to the following standards:

GOST R EN 13779-2007 Ventilation in non-residential buildings. Technical requirements to ventilation and air conditioning systems

GOST R ISO 14644-3-2007 Clean rooms and associated controlled environments. Part 3. Test methods

GOST R ISO 14644-4-2002 Clean rooms and associated controlled environments. Part 4. Design, construction and commissioning

GOST R ISO 14644-5-2005 Clean rooms and associated controlled environments. Part 5. Operation

GOST R 52249-2009 Rules for the production and quality control of medicines

GOST R 52539-2006 Air purity in medical institutions. General requirements

GOST ISO 14644-1-2002 Clean rooms and associated controlled environments. Part 1. Classification of air purity

Note - When using this standard, it is advisable to check the validity of the reference standards in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet or using the annual information index "National Standards", which was published as of January 1 of the current year, and on issues of the monthly information index "National Standards" for the current year. If an undated reference standard is replaced, it is recommended that the current version of that standard be used, taking into account any changes made to that version. If a dated reference standard is replaced, it is recommended to use the version of that standard with the year of approval (adoption) indicated above. If, after the approval of this standard, a change is made to the referenced standard to which a dated reference is made that affects the provision referred to, it is recommended that that provision be applied without regard to that change. If the reference standard is canceled without replacement, then the provision in which a reference to it is given is recommended to be applied in the part that does not affect this reference.

3 Terms and definitions

This standard uses terms and definitions in accordance with GOST ISO 14644-1, as well as the following terms with corresponding definitions:

3.1 recovery time: The time required for the particle concentration in the room to decrease by 100 times compared to the initial, sufficiently large particle concentration.

Note - The method for determining the recovery time is given in GOST R ISO 14644-3 (clause B.12.3).

3.2 air exchange rate N: Air flow ratio L(m/h) to room volume V(m), N=L/V, h.

3.5 air flow L: The amount of air supplied to the room per hour, m/h.

4 Principles of energy saving in clean rooms

4.1 Energy saving measures

Energy saving measures can be general for all buildings, industries and HVAC systems or specific for clean rooms.

4.2 General measures

General measures include:

- minimizing heat gain and loss, insulating buildings;

- heat recovery;

- air recirculation with bringing the proportion of outside air to a minimum, where this is not prohibited by mandatory standards;

- placement of energy-intensive industries in climatic zones that do not require excessively high costs for heating and air humidification in winter, cooling and dehumidification in summer;

- use of highly efficient fans, air conditioners and chillers;

- exclusion of unreasonably strict ranges of temperature and humidity changes;

- maintaining air humidity in winter at a minimum level;

- removal of excess heat from equipment primarily by local systems built into the equipment, rather than by means of ventilation and air conditioning, etc.

- use of protective equipment for workplaces and fume hoods that do not require the removal of large volumes of air when working with hazardous substances (for example, closed equipment, systems with limited access, isolators);

- use of equipment with power reserve (for example, air conditioners, filters, etc.), keeping in mind that equipment with a higher rated power consumes less energy to perform a given task;

Note - At the same air flow, a fan (air conditioner) with a higher rated power will have less energy consumption.


- other measures in accordance with 4.4.2.

4.3 Special measures

These measures take into account the characteristics of cleanrooms and include:

- reducing to a reasonable minimum the area of ​​clean rooms and other air-conditioned premises;

- exclusion of setting unreasonably high cleanliness classes;

- justification of air exchange rates, avoiding excessively high values, including due to unreasonably stringent requirements for recovery time;

- use of HEPA and ULPA filters with low pressure drop, for example Teflon membrane filters;

- sealing leaks at the joints of enclosing structures;

- application of local protection when setting a high class in a limited area based on the requirements of the process;

- reducing the number of personnel or using unmanned technologies (for example, the use of closed equipment, isolators);

- reduction of air consumption during non-working hours;

- determination at the stages of certification and operation of the real value of the power reserve provided by the project;

- strict compliance with operating requirements, including clothing, personnel hygiene, training, etc.;

- determination of the really necessary air flow rates during testing and during operation and regulation of air flow rates to minimum values, based on these data;

- operation of a clean room with reduced energy consumption, subject to compliance with the requirements for the cleanliness class;

- confirmation of the ability to operate at reduced energy consumption through ongoing cleanliness control (monitoring) and repeated certifications;

- other measures in accordance with 4.4.2.

4.4 Energy saving steps

4.4.1 General

Energy resource requirements are assessed at the design, certification and operation stages.

The main factor determining the need for energy resources is air consumption (air exchange rate).

Air flow must be determined at the design stage. In this case, some reserve is provided to take into account uncertainty due to the lack of accurate data on the release of particles by equipment, process and for other reasons.

At the certification stage, the correctness of design solutions is checked and the real reserve of ventilation and air conditioning systems in terms of air flow is determined.

During operation, the compliance of the clean room with the specified cleanliness class is monitored.

NOTE This approach differs from current practice. Traditionally, air flow is determined at the design stage (in the project); in a constructed room, during certification, the compliance of the air flow with that specified in the project is checked, and this air flow is maintained during operation. In this case, the design provides for redundancy in air flow due to the presence of some uncertainty, but this redundancy is not revealed during testing. Further, the room is operated at excessively high air exchange rates, which leads to excessive energy consumption.


This standard provides for the determination of the real reserve in design solutions and the operation of clean rooms at real necessary expenses air, which turn out to be less than the design values ​​by the amount of the reserve established during testing.

The standard provides a flexible procedure for determining air exchange rates.

4.4.2 Design

General and specific energy saving measures (see 4.2-4.3) should be taken taking into account real possibilities.

Along with this, the following should be provided:

- regulation of air flow by means of automation, including setting modes for working and non-working hours and providing microclimate parameters depending on specific conditions;

- transition from ensuring a cleanliness class throughout the entire room to local protection, in which the cleanliness class is set and controlled only in the work area, or a higher cleanliness class is provided in the work area than in the rest of the room;

- accounting for the operation of laminar flow cabinets and laminar flow zones. In this case, the air flow from the laminar flow cabinet (zone) is added to the air flow to ensure cleanliness from the air conditioner;

- for rooms where only local protection is required, the advisability of using a horizontal air flow instead of a vertical one should be considered. In some cases, it is possible to create an air flow at an angle, for example at an angle of 45° relative to the ceiling;

- reduction of resistance to air flow on all elements of the air flow path, including due to low air speed in the air duct.

Energy saving methods differ for rooms (zones) with unidirectional and non-unidirectional flow.

4.4.2.1 Unidirectional airflow

For unidirectional flow areas, air velocity is a key factor. It is recommended to maintain a unidirectional flow speed of approximately 0.3 m/s if regulatory documents not otherwise provided. In case of contradiction, the speed value established by regulatory documents is provided. For example, GOST R 52249 (Appendix 1) provides for a unidirectional air flow speed in the range of 0.36-0.54 m/s; GOST R 52539 - 0.24-0.3 m/s (in operating rooms and intensive care wards).

4.4.2.2 Non-unidirectional air flow

For cleanrooms with non-unidirectional (turbulent) flow, the decisive factor is the air exchange rate (see section 5).

4.4.3 Attestation

Certification (testing) of clean rooms is carried out in accordance with GOST R ISO 14644-3 and GOST R ISO 14644-4.

In addition to this, it is necessary to check the possibility of maintaining the cleanliness class with a margin at reduced multiplicities and real particle emission values, i.e. determine the reserve of ventilation and air conditioning systems. This is done for the equipped and operating states of the cleanroom.

4.4.4 Operation

It is necessary to confirm the possibility of working with reduced air exchange rates in real mode when performing a technological process with a specified number of personnel, using this clothing, etc.

For this purpose, periodic and/or continuous monitoring of particle concentration is provided.

Measures should be taken to reduce the release of particles from all possible sources, the entry of particles into the room, and the effective removal of particles from the room, including from personnel, processes and equipment, and cleanroom structures (convenience and efficiency of cleaning).

The main measures to reduce particle emissions are:

1) staff:

- use of appropriate technical clothing;

- compliance with hygiene requirements;

- correct behavior based on the requirements of cleanliness technology;

- education;

- use of sticky mats at the entrance to clean rooms;

2) processes and equipment:

- cleaning (washing, cleaning);

- use of local suction (removal of contaminants from the place of their release);

- the use of materials and structures that do not adsorb contamination and ensure efficiency and convenience of cleaning;

3) cleaning:

- correct technology and required frequency of cleaning;

- use of equipment and materials that do not emit particles;

- control over cleaning.

5 Air exchange rate

5.1 Setting the air exchange rate

Taking into account the key role of air flow in energy consumption, air exchange rates should be assessed for all factors influencing them:

a) outdoor air requirements according to sanitary standards;

b) compensation for local exhaust (suction);

c) maintaining differential pressure;

d) removing excess heat;

e) ensuring a given cleanliness class.

Measures should be taken to reduce air flows not related to cleanliness ( listings a-d) to values ​​less than necessary to ensure cleanliness (e).

To calculate the ventilation and air conditioning system, the multiplicity of the worst (largest) value is taken.

The required frequency of air exchange (air flow) depends on the requirements for the cleanliness class (maximum permissible concentration particles in the air) and recovery time.

The method for calculating the air exchange rate to ensure cleanliness is given in Appendix A.

5.2 Ensuring cleanliness class

The classification of clean rooms is given in GOST ISO 14644-1.

Requirements for cleanliness classes are set in accordance with regulatory documents (for the production of medicines - according to GOST R 52249, medical institutions - according to GOST R 52539) or a design assignment (technical assignment for the development) of a clean room based on the specifics of the technological process and by agreement between the customer and performer.

At the design stage, the intensity of particle emission can only be approximately estimated; therefore, a reserve of air exchange rates should be provided.

5.3 Recovery time

The recovery time is taken in accordance with regulatory requirements for the cases provided for therein. For example, GOST R 52249 sets a recovery time of 15-20 minutes for the production of sterile medicines. In other cases, the customer and the contractor can set other recovery time values ​​(30, 40, 60 minutes, etc.) based on specific conditions.

The methodology for calculating particle concentration reduction and recovery time is given in Appendix A.

Airborne particle concentrations and recovery times are strongly influenced by personnel clothing and other operating conditions (see example in Appendix B).

If there is an area with unidirectional air flow in the room, its effect on air cleanliness should be considered (see Appendix A).

Appendix A (informative). Dependence of particle concentration and recovery time on the air exchange rate

Appendix A
(informative)

The main source of contamination in a clean room is humans. In many cases, emissions of pollutants from equipment and structures are small compared to emissions from humans and can be neglected.

Particle concentration C in the air of rooms with supply ventilation at the time t is calculated (in the general case) by the formula

Where C- particle concentration at the initial moment (when the ventilation system is turned on or after pollutants are introduced into the air) t=0, particles/m;

n- intensity of particle emission indoors, particles/s;

V- volume of the room, m;

k- coefficient calculated using formula (A.2);

k- coefficient calculated using formula (A.3).

where is the efficiency coefficient of the ventilation system, for clean rooms with non-unidirectional (turbulent) flow it is assumed = 0.7;

Q- supply air flow, m/s;

q- the volume of air penetrating into the room due to leakage (air infiltration), m/s;

- share of recirculated air;

- efficiency of filtration of recirculated air.

where is the efficiency of outdoor air filtration;

C- concentration of particles in the outside air, particles/m;

C is the concentration of particles in the air entering due to infiltration, particles/m.

Formula (A.1) includes two terms: variable C and permanent C.

C=C+C, (A.4)

Where ,
.

The variable part characterizes the transition process when the concentration of particles in the room air decreases after turning on ventilation or introducing pollutants into the room.

The constant part characterizes the steady-state process in which the ventilation system removes particles generated in the room (by personnel, equipment, etc.) and entering the room from the outside (with the supply air, due to infiltration).

In practical calculations we take:

- air infiltration equal to zero, q=0;

- filtration efficiency equal to 100%, i.e. =0 and =0.

Then the coefficients are equal

k= Q=0.7Q,

k=0

Formula (A.1) is simplified

Where N- air exchange rate, h;

Q = N·V.(A.6)

Example A.1 Cleanroom in equipped condition (no personnel, no process in progress)

Consider a clean room with the following parameters:

- volume V =100 m ;

- ISO cleanliness class 7; equipped state; specified particle size 0.5 µm (352000 particles/m );

0.5 µm indoors =10 particles/s;

- WITH =10 particles/m , particles with dimensions 0.5 µm;

- air exchange rate N, corresponds to the series 15*, 10, 15, 20, 30;
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- air flow Q, m /s, calculated using formula (A.6)

where 3600 is the number of seconds in 1 hour;

- the efficiency coefficient of the ventilation system for clean rooms with non-unidirectional (turbulent) flow is accepted =0,7.

The reduction in particle concentration after time t is calculated using formula (A.5):

Where .

Note - When calculating, time should be expressed in seconds.

The calculation data is given in Table A.1.

Table A.1 - Variation of particle concentration with size 0.5 µm in the air depending on the frequency of air exchange over time in the equipped state

The data in Table A.1 is shown graphically in Figure A.1.*
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* The text of the document corresponds to the original. - Database manufacturer's note.


From Table A.1 and Figure A.1 it is clear that the condition for a recovery time of less than 15-20 minutes (reducing the concentration of particles in the air by 100 times) is met for air exchange rates of 15, 20 and 30 hours . If we allow the recovery time to be 40 minutes, then the frequency of air exchange can be reduced to 10 hours . In operation, this means switching ventilation systems to operating mode 40 minutes before starting work.

Figure A.1 - Change in the concentration of particles with sizes of at least 0.5 microns in the air depending on the frequency of air exchange over time in the equipped state

Figure A.1 - Change in particle concentration with size 0.5 µm in the air depending on the frequency of air exchange over time in the equipped state

Example A.2. Clean room in operation

The clean room is the same as in example A.1.

Conditions:

- operating condition;

- number of personnel 4 people;

- intensity of release of particles with sizes 0.5 microns by one person is equal to 10 particles/s (cleanroom clothing is used);

- there is practically no emission of particles from the equipment, i.e. only the emission of particles by personnel is taken into account;

- n =4·10 particles/s;

- WITH =10 particles/m .

Let us calculate the decrease in particle concentration over time using the formulas

,

The calculation results are shown in Table A.2.

Table A.2 - Variation of particle concentration with size

The data in Table A.2 is shown graphically in Figure A.2.

Figure A.2 - Change in the concentration of particles with sizes of at least 0.5 microns in the air depending on the frequency of air exchange over time (clothing for clean rooms is used)

Figure A.2 - Change in particle concentration with size 0.5 microns in the air depending on the frequency of air exchange over time (clean room clothing is used)

As can be seen from example A.2, with an air exchange rate of 10 hours ISO class 7 is achieved 35 minutes after the ventilation system starts operating (if there are no other sources of pollution). Reliable maintenance of ISO cleanliness class 7 is ensured with a margin at an air exchange rate of 15-20 hours .

Appendix B (informative). Assessing the impact of clothing on pollution levels

Appendix B
(informative)

Let's consider the effect of clothing on the concentration of particles in the air for the following cases:

- ordinary clothing for clean rooms - jacket/trousers, particle emission rate 10 particles/s;

- high-performance clothing - overalls for clean rooms, particle emission rate 10 particles/s.

The data in Table B.1 was obtained using the methodology given in Appendix A.

Table B.1 - Concentrations of particles with a size of 0.5 microns in the air for various types of clothing for clean rooms at an air exchange rate of 10 hours

Note - It is assumed that personnel comply with the requirements of hygiene, behavior, dressing and other operating conditions of clean rooms in accordance with GOST R ISO 14644-5.

The data in Table B.1 is shown graphically in Figure B.1.

Figure B.1 - Concentrations of particles with sizes of at least 0.5 microns in the air for various types of clothing at an air exchange rate of 10 h_(-1)

Figure B.1 - Concentrations of particles with sizes of 0.5 microns in the air for various types of clothing at an air exchange rate of 10 hours

From Table B.1 and Figure B.1 it can be seen that the use of high-performance clothing can achieve ISO class 7 cleanliness levels with an air exchange rate of 10 h and a recovery time of 40 minutes (if there are no other sources of contamination).

Bibliography

Electronic document text
prepared by Kodeks JSC and verified against:
official publication
M.: Standartinform, 2015