Categorization of premises for explosion and fire hazard: TCH. Categories of premises for explosion and fire hazard: examples

In modern production a large volume of combustible and explosive materials is processed and applied. Operating technological lines are oriented to high speed of operations. Increase in productivity causes the increase to critical limits of such parameters as temperature, pressure, ratio of oxidizer and combustible components. In this regard, the potential threat of explosions and fires is increasing, the destructive power of which causes huge material damage, leads to injuries and the death of employees of enterprises. As analysis of major accidents shows, their consequences extend not only to the buildings themselves, but also to nearby residential areas. The evaluation of the cause-effect relationships of technical disasters allows taking the necessary preventive measures not only during the operation of production systems, but also in the development of technical design for design, drawing up schemes and plans, and also during construction. Within the framework of this activity, categorization of premises for explosion and fire danger is used. Let's consider this classification in detail.

General information

Calculation of the category of fire and fire hazard of the premises can objectively establish a conditional level of the threat of a technical catastrophe. Based on the parameters obtained, the development and justification of organizational and technical solutions are carried out. They, in turn, ensure optimal exploitation of areas within the limits of acceptable risk.

Normative base

To preserve life, health of people, property of legal entities, the municipality and the state from fires, Federal Law No. 123 was approved. Its provisions determine the key directions of technical regulation in the sphere in question. The normative act establishes the main security requirements for the objects, including buildings, buildings, premises, buildings, fire-technical and general-purpose products. Specifies the provisions of this Federal Law Code. In accordance with it, categorization of premises for explosion and fire danger is carried out. SP 12. 13130. 2009 formulates the methodology for the classification of areas. It depends on the amount of materials and substances that are or are used within them. Specialists also take into account the peculiarities of technological processes. According to the Code of Regulations, the category of fire and fire hazard of storage facilities and production facilities is defined. Areas of other purposes can not be separated.

Classification criteria

Categories of premises for fire and fire hazard are determined in accordance with the type of combustible materials and substances present in them, their quantity and properties. In addition, space-planning solutions of areas and characteristics of technological processes that are within their limits are taken into account. The properties of materials and substances are established on the basis of the results obtained during the test, or by calculations using standard methods taking into account the state indicators (temperature, pressure, etc.). It is allowed to use reference, officially published information on the properties of materials and substances. It is also possible to use indicators for mixtures of materials and substances for the most dangerous component.

The principles of separation

Categories of premises for fire and fire hazard are established taking into account the accident factors, the properties of the final and the initial product, the characteristics of the equipment, etc. The following principles are based on the existing separation methodology:

1. Recognition of the possibility of the normative (specific) power of the accident.
2. Accounting for the amount of materials and substances that contribute to the formation of dusty or steam-air mixtures that create a threat.
3. Taking into account the properties of raw materials used in production.

When categorizing premises for fire and fire hazard, specialists should take the most unfavorable version of the disaster or the period of normal operation of the technological system and the elements that make up it. These principles formed the basis for the requirements that must be met when conducting the classification.

Categorization of premises for explosion and fire hazard: JV

Five groups and three classes are defined to assess and compare the threat level and the degree of protection. The table shows their characteristics.

In accordance with these groups, the categorization of premises for explosion and fire danger is carried out. The tablets presented in the article indicate the object's software class. They are an inalienable requirement of the existing normative documents.

Note

Excess pressure, which is 5 kPa, acts as a quantitative measure for dust and vapor-air mixtures. This indicator does not endanger the lives of maintenance personnel. Categories of premises for fire and fire hazard B1-B4 are determined using the energy parameter. It is expressed in a specific load (MJ / m2).

Categorization of premises for explosion and fire hazard (GOST)

When classifying, it is necessary to take into account the physico-chemical characteristics of materials and substances and their parameters:

1. Group of flammability.
2. Maximum explosion pressure and rate of increase.
3. Conditions of spontaneous combustion (thermal).
4. Concentration levels of fire spread.
5. Burnout rate.
6. Autoignition temperature.
7. Oxygen index.
8. Flash point.
9. Ignition energy (minimum).
10. Temperature limit for flame propagation.
11. The ability to burn and explode on contact with other compounds, air oxygen, water.
12. The temperature of the flame.
13. Coefficient of smoke formation.
14. Parameters of toxicity of products formed during combustion of polymeric substances and materials.
15. The standard speed of fire propagation.
16. The minimum explosive concentration of oxygen.
17. Fire propagation index.
18. Ignition temperature.
19. Phlegmatizing minimum concentration of phlegmatizer.

In this case, the number of parameters sufficient and necessary to characterize the explosion and fire hazard of materials and substances in the conditions of their processing, production, storage and transportation, is established by the developer of TU and GOST. This function can be performed by the designer of the security system at the facility.

Classification of substances

The categorization of premises for explosion and fire hazard is carried out taking into account the following division:

1. Gases are substances in which the absolute vapor pressure at temp. 25 deg. Is equal to or greater than 101.3 kPa.
2. Solid materials have an incandescent (melting) temperature of more than 50 degrees. And not having it at all.
3. Liquids are substances in which the saturated vapor pressure at temp. 25 deg. And a pressure of 101.3 kPa is less than 101.3 kPa.
4. Dusts are dispersed solid materials, the particle size of which is less than 850 microns.

Key factors

The categorization of premises for fire and fire hazard is carried out taking into account the following conditions:

1. The most unfavorable consequences of failure of one device are taken into account.
2. All the contents of the installation enter the room.
3. During the time required for shutdown, there is a simultaneous leakage of substances from the pressure and suction pipelines.
4. The estimated stop time with the probability of failure of the automatic system is no more than 10-6 per year or provides redundancy of the elements. At a higher rate, the automatic shutdown period is 120 seconds, the manual setting is 300 seconds.
5. Evaporation occurs from the surface of spilled fuel from apparatuses and tanks with an open mirror and freshly dyed planes. Its area is determined from the calculation of 1 liter per 1 sq. Km. M of the room. In the absence of reference data on combustible mixtures, the indicator is calculated on the basis that 1 liter of liquid containing 70% or less of solvents is spread over 0.5 square meters. M.
6. The duration of evaporation is assumed equal to the period of complete evaporation, but not more than 3600 seconds.
7. In the event of a malfunction of the apparatus with dust, its mass of particles present in the installation is taken into account. In this case dust accumulation is adopted in accordance with the conditions of normal operating conditions.
8. Free volume in the room can be taken equal to 80% of the total.

Methods for determining

How exactly is the categorization of premises for explosion and fire hazard? TCH 474-2013 - Code of established practice, formulates the classification methodology. The distinction is made using deterministic and probabilistic approaches. With the help of the latter, the accidental nature of emergency situations is taken into account. The probabilistic method allows to estimate the actual level of danger in general and in particular cases. The deterministic approach is based on a quantitative analysis of the recovered potential energy release in technical catastrophes. It is necessary to note the peculiarity of the methods used in determining the category of premises for explosion and fire hazards. Examples from practice indicate that the approaches used characterize the probability of an accident without taking into account the origin of the source of ignition and the area of consequences.

Technical Code

In accordance with its provisions, the general categorization of premises for explosion and fire danger is carried out. TCH is not applied to objects classified according to special rules and regulations. The division, carried out in accordance with the code, should be used to formulate requirements for securing the areas in the planning, determining the number of storeys, the dimensions of the squares. Compartments, the organization of evacuation of people, the installation of engineering equipment, the adoption of constructive solutions, etc. The requirements must be taken into account in projects for the construction, modernization, reconstruction, technical re-equipment, as well as for adjusting technological processes during the use of facilities.

Scope of application

In what cases are the categories of premises determined by explosion and fire hazard? Examples of activities in which this classification is necessary is the following:

1. Exploitation.
2. Design.
3. Replacement of equipment.
4. Change in technology.
5. Reconstruction.
6. Substitution of the production volume.

Stages

First of all, it should be said that not every organization can categorize premises for explosion and fire danger. License - the main document authorizing the production of such activities. The work consists of two stages. At the first stage, the necessary information is collected:

1. Dimensions and characteristics of objects.
2. Layout of equipment (working drawings).
3. Technical certificate.
4. Technical regulations.
5. Parameters and diagram of the ventilation system.
6. Structure of automatic control of production parameters.
7. Scheme of fire extinguishing system.
8. Other relevant data.

If the work is carried out at the design stage, then the necessary information is taken from the technical documents. The second stage is, in fact, the calculation of categories.

Features of regulatory requirements

After checking and establishing the category of premises, prescriptions are formulated. The protection of objects is provided in accordance with the State Standard. It, in particular, prescribes the presence of fire prevention systems (SSP) and fire protection (SDR). In addition, organizational and technical measures (OTM) are envisaged. The Gosstandart also formulates requirements with regard to the ways to ensure the protection of the SSP and SDR systems, which assume the categorization of premises for fire and fire hazard. NPB 105.03 (regulatory rules) define prescriptions for the protection of AOP and AUPT (automatic detection and extinguishing systems). These requirements are mandatory for organizations and enterprises, regardless of departmental ownership and ownership, as well as individuals. Type АУПТ, a kind of extinguishing means, a way of elimination of ignition, type of the equipment are established according to technological features of protected objects. This takes into account the draft fire protection scheme and the requirements of regulatory documents. Areas for engineering installations with powerful processes and other facilities in which combustible materials are not contained can be equipped with AUOP and AUPT. In rooms where there is a fire alarm, it is necessary to install a security system. With the area of the object to be equipped with AUPT, from 40% or more of the total size of the floors, it is necessary to provide for the installation of this system as a whole throughout the structure. For a building belonging to the category B1, S is reduced by 20%. In this case, the area of the structures of group B3 is allowed to be increased by the same amount.

Conclusion

As practice shows, quite often performers and specialists have problems in categorizing buildings and premises. Meanwhile, a competent and qualified establishment of an object group is of decisive importance at the design and construction stage of facilities. If the categorization work is carried out correctly, then all technical issues that arise later will be solved correctly. According to the provisions of Federal Law No. 69, each manager is required to comply with the requirements of the PB. This means that the enterprise must provide a set of organizational and preventive measures aimed at reducing the likelihood of emergence of threats to the safe operation of production facilities, the life and health of employees, the preservation of material and industrial values. Admissible errors in determining the necessary measures can lead to their redundancy or insufficiency. This, in turn, will lead to inefficient material costs for fire-fighting measures.