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About approval of norms fire safety"Determination of categories of premises, buildings and outdoor installations for explosion and fire hazard" (NPB 105-03)

In accordance with the Federal Law of December 21, 1994 No. 69-FZ "On Fire Safety" (Collected Legislation Russian Federation, 1994, No. 35, art. 3649; 1995, no. 35, art. 3503; 1996, no. 17, art. 1911; 1998, No. 4, Art. 430; 2000, no. 46, art. 4537; 2001, No. 1 (part I), art. 2, No. 33, (part I), Art. 3413; 2002, No. 1 (part I), Art. 2, no. 30, art. 3033; 2003, no. 2, art. 167); I order:

1. Approve the attached fire safety standards "Definition of categories of premises, buildings and outdoor installations for explosion and fire hazard" (NPB 105-03).

2. Bring this order to the Deputy Ministers, heads (heads) of departments, head of the Main Directorate of the State Fire Service, heads of departments and an independent department of the central apparatus of the EMERCOM of Russia, heads of regional centers for civil defense, emergencies and disaster relief, fire technical research and educational institutions according to established order.

Minister S.K. Shoigu

FIRE SAFETY STANDARDS

Developed by the Main Directorate of the State Fire Service of the Ministry of the Russian Federation for Civil Defense, Emergencies and Disaster Relief (GUGPS EMERCOM of Russia) and the Federal government agency"All-Russian Order "Badge of Honor" Research Institute of Fire Defense" of the Ministry of the Russian Federation for Civil Defense, Emergencies and Disaster Relief (FGU VNIIPO EMERCOM of Russia).

Submitted and prepared for approval by the regulatory and technical department of the Main Directorate of the State Fire Service (GUGPS EMERCOM of Russia).

By letter of the Ministry of Justice of Russia dated June 26, 2003 No. 07/6463-YUD, they were recognized as not requiring state registration.

Approved by order of the Ministry of Emergency Situations of Russia dated June 18, 2003 No. 314.

Instead of NPB 105-95, NPB 107-97.

These standards establish a methodology for determining the categories of premises and buildings (or parts of buildings between fire walls - fire compartments) 1 for production and storage purposes in terms of explosion and fire hazard, depending on the amount and fire and explosion hazardous properties of the substances and materials located (circulating) in them, taking into account the characteristics of technological processes of production facilities located in them, as well as a methodology for determining the categories of outdoor installations for production and storage purposes 2 in terms of fire hazard.

The methodology for determining the categories of premises and buildings in terms of explosion and fire hazard should be used in design estimates and operational documentation for buildings, premises and outdoor installations.

Categories of premises and buildings of enterprises and institutions are determined at the stage of designing buildings and structures in accordance with these standards and departmental standards for technological design, approved in the prescribed manner.

The requirements of the standards for outdoor installations must be taken into account in projects for the construction, expansion, reconstruction and technical re-equipment, with changes in technological processes and during the operation of outdoor installations. Along with these standards, one should also be guided by the provisions of departmental technological design standards regarding the categorization of outdoor installations, approved in the prescribed manner.

In the field of explosion hazard assessment, these standards distinguish categories of fire and explosion hazardous premises and buildings, a more detailed classification of which by explosion hazard and the necessary protective measures should be regulated by independent normative documents.

The categories of premises and buildings defined in accordance with these standards should be used to establish regulatory requirements for ensuring the explosion and fire safety of these premises and buildings in relation to planning and development, number of storeys, areas, placement of premises, constructive solutions, engineering equipment.

These rules do not apply:

on premises and buildings for the production and storage of explosives (hereinafter referred to as explosives), means of initiating explosives, buildings and structures designed in accordance with special norms and rules approved in the prescribed manner;

for outdoor installations for the production and storage of explosives, means of initiating explosives, outdoor installations designed in accordance with special norms and rules approved in the prescribed manner, as well as for assessing the level of explosion hazard of outdoor installations.

The terms and their definitions are adopted in accordance with the regulations on fire safety.

The term "Outdoor installation" in these standards means a set of devices and technological equipment located outside buildings, with load-bearing and service structures.

1. GENERAL PROVISIONS

1. In terms of explosion and fire hazard, premises are divided into categories A, B, C1 - C4, D and D, and buildings - into categories A, B, C, D and D.

According to fire hazard, outdoor installations are divided into categories A n, B n, V n, Mr. and D n.

2. Categories of explosion and fire hazard of premises and buildings are determined for the most unfavorable period in relation to fire or explosion, based on the type of combustible substances and materials in apparatus and premises, their quantity and fire hazardous properties, and features of technological processes.

The categories of fire hazard of outdoor installations are determined based on the type of combustible substances and materials in outdoor installations, their quantity and fire hazardous properties, and the features of technological processes.

3. Determination of fire hazardous properties of substances and materials is carried out on the basis of test results or calculations according to standard methods, taking into account state parameters (pressure, temperature, etc.).

It is allowed to use reference data published by leading research organizations in the field of fire safety or standard reference data issued by the State Service.

It is allowed to use fire hazard indicators for mixtures of substances and materials according to the most dangerous component.

Substances and materials capable of exploding and burning when interacting with water, atmospheric oxygen or with each other in such an amount that the calculated overpressure of the explosion in the room exceeds 5 kPa

explosive and fire hazardous

flammable

G

3. METHODS FOR CALCULATION OF THE CRITERIA OF THE EXPLOSION HAZARD OF PREMISES

Selection and justification of the design option

6. When calculating the values ​​of the fire and explosion hazard criteria, the most unfavorable variant of the accident or the period of normal operation of the apparatus, in which the largest number substances or materials that are most hazardous in terms of the consequences of an explosion.

If the use of calculation methods is not possible, it is allowed to determine the values ​​of the fire and explosion hazard criteria based on the results of relevant research work, agreed and approved in the prescribed manner.

7. The amount of substances entering the room that can form explosive gas-air or vapor-air mixtures is determined based on the following prerequisites:

a) there is a design accident of one of the vehicles in accordance with paragraph 6;

b) all the contents of the apparatus enter the room;

c) there is a simultaneous leakage of substances from the pipelines supplying the apparatus in the forward and reverse flows during the time necessary to turn off the pipelines.

The estimated shutdown time of pipelines is determined in each specific case based on the actual situation and should be minimal, taking into account passport data for locking devices, the nature of the process and the type of design accident.

the response time of the automatic pipeline shutdown system according to the passport data of the installation, if the probability of failure of the automatic system does not exceed 0.000001 per year or redundancy of its elements is provided;

120 s if the probability of failure of the automation system exceeds 0.000001 per year and redundancy of its elements is not provided;

300 s with manual shutdown.

The “acting time” and “off time” should be understood as the period of time from the beginning of a possible inflow of a combustible substance from the pipeline (perforation, rupture, change in nominal pressure, etc.) until the complete cessation of the flow of gas or liquid into the room. High-speed shut-off valves should automatically shut off the gas or liquid supply in the event of a power failure.

In exceptional cases, in accordance with the established procedure, it is allowed to exceed the above values ​​for the shutdown time of pipelines by a special decision of the relevant federal ministries and other federal executive authorities in agreement with the Gosgortekhnadzor of Russia at the production and enterprises under its control and the Russian Emergencies Ministry;

d) evaporation occurs from the surface of the spilled liquid; the evaporation area during spillage on the floor is determined (in the absence of reference data) based on the calculation that 1 liter of mixtures and solutions containing 70% or less (by weight) of solvents is spilled over an area of ​​0.5 m 2, and other liquids - over 1 m 2 of the floor of the room;

e) liquid also evaporates from containers operated with an open liquid surface and from freshly painted surfaces;

8. The amount of dust that an explosive mixture can form is determined from the following assumptions:

a) the design accident was preceded by dust accumulation in the production room occurring under normal operating conditions (for example, due to dust release from leaky production equipment);

b) at the time of the design accident, a planned one ( repair work) or a sudden depressurization of one of the technological apparatus, followed by an emergency release into the room of all the dust in the apparatus.

9. The free volume of the premises is defined as the difference between the volume of the premises and the volume occupied by the technological equipment. If it is impossible to determine the free volume of the room, then it can be taken conditionally equal to 80% of the geometric volume of the room.

Calculation of the explosion overpressure for combustible gases, vapors of flammable and combustible liquids

10. Explosion overpressure DP for individual combustible substances consisting of C, H, O, N, C1, Br, I, F atoms, is determined by the formula

(1)

where P max - maximum explosion pressure of a stoichiometric gas-air or vapor-air mixture in a closed volume, determined experimentally or from reference data in accordance with the requirements of paragraph 3. In the absence of data, it is allowed to take P max equal to 900 kPa;

P 0- initial pressure, kPa (may be taken equal to 101 kPa);

T - the mass of combustible gas (GG) or vapors of flammable liquids (FL) and combustible liquids (FL) released as a result of a design accident into the room, calculated for GG by formula (6), and for FL and GL vapors by formula (11), kg;

Z- coefficient of participation of fuel in the explosion, which can be calculated on the basis of the nature of the distribution of gases and vapors in the volume of the room according to the application. Allowed to take a value Z according to the table 2;

V St - free volume of the room, m 3;

r g.p is the density of the gas or vapor at design temperature tp, kg × m -3, calculated by the formula

(2)

where M- molar mass, kg×kmol -1;

V 0 - molar volume equal to 22.413 m 3 × kmol -1;

tp- design temperature, °C. The maximum possible air temperature in a given room in the corresponding climatic zone or the maximum possible air temperature according to the technological regulations should be taken as the design temperature, taking into account a possible increase in temperature in an emergency. If such a design temperature value tp for some reason it cannot be determined, it is allowed to take it equal to 61 ° C;

With ST- stoichiometric concentration of HG or vapors of flammable liquids and GL,% (vol.), Calculated by the formula

(3)

where - stoichiometric coefficient of oxygen in the combustion reaction;

n C, n H, nO, n X¾ the number of atoms C, H, O and halides in the fuel molecule;

K n - coefficient that takes into account the leakage of the room and the non-adiabatic nature of the combustion process. Allowed to take K n equal to 3.

table 2

11. Calculation D R for individual substances, except for those mentioned in clause 10, as well as for mixtures, it can be performed according to the formula

(4)

where H T - heat of combustion, J×kg -1;

r in is the air density before the explosion at the initial temperature T 0, kg × m -3;

C p- heat capacity of air, J × kg -1 × K -1 (it is allowed to be taken equal to 1.01 × 10 3 J × kg -1 × K -1);

T 0- initial air temperature, K.

12. If flammable gases, flammable or combustible liquids are used in the room when determining the mass value T, included in formulas (1) and (4), it is allowed to take into account the operation of emergency ventilation if it is provided with backup fans, automatic start-up when the maximum permissible explosion-proof concentration is exceeded and power supply according to the first category of reliability (PUE), subject to the location of devices for removing air from the room in close proximity to the place of a possible accident.

At the same time, the mass m combustible gases or vapors of flammable or combustible liquids heated to a flash point and above that enter the volume of the room should be divided by the coefficient TO, determined by the formula

TO = A T + 1, (5)

where A - the multiplicity of air exchange created by emergency ventilation, s -1;

T - the duration of the entry of flammable gases and vapors of flammable and combustible liquids into the volume of the room, s (accepted according to clause 7).

13. Weight m, kg of gas entering the room during a design accident is determined by the formula

T = (Va + V T) r r, (6)

where V a - the volume of gas released from the apparatus, m 3 ;

V T- the volume of gas released from the pipelines, m 3.

V a = 0,01R 1 V, (7)

where P1- pressure in the apparatus, kPa;

V- apparatus volume, m 3 ;

V T = V 1T + V 2T, (8)

where V 1T - the volume of gas that came out of the pipeline before it was turned off, m 3;

V 2T - the volume of gas released from the pipeline after it was turned off, m 3;

V 1T \u003d qT, (9)

q- gas consumption, determined in accordance with the technological regulations, depending on the pressure in the pipeline, its diameter, the temperature of the gas medium, etc., m 3 × s -1;

T - time determined according to clause 7, s;

where P2- maximum pressure in the pipeline according to the technological regulations, kPa,

r

L

14. Liquid vapor mass m, which entered the room in the presence of several sources of evaporation (the surface of a spilled liquid, the surface with a freshly applied composition, open containers, etc.), is determined from the expression

t \u003d t p + t cap + t sv. , (11)

where m p - mass of liquid evaporated from the spill surface, kg;

t emk

t St. env - mass of liquid evaporated from the surfaces on which the applied composition is applied, kg.

In this case, each of the terms in formula (11) is determined by the formula

m = W F and T, (12)

where W- evaporation rate, kg×s -1 ×m -2 ;

F and- evaporation area, m 2, determined in accordance with paragraph 7, depending on the mass of the liquid t p that went out into the room.

If the emergency situation is associated with the possible ingress of liquid in the atomized state, then it should be taken into account in formula (11) by introducing an additional term that takes into account the total mass of the incoming liquid from the spraying devices, based on the duration of their work.

15. Weight m p, kg, of the liquid released into the room is determined in accordance with clause 7.

16. Evaporation rate W is determined by reference and experimental data. For flammable liquids not heated above ambient temperature, in the absence of data, it is allowed to calculate W according to the formula

W \u003d 10 -6 h P n, (13)

where h- coefficient taken according to the table. 3 depending on the speed and temperature of the air flow above the evaporation surface;

R n - saturation vapor pressure at design liquid temperature t p, determined from the reference data in accordance with the requirements of paragraph 3, kPa.

Table 3

Explosion overpressure calculation for combustible dusts

17. Calculation of the overpressure of the explosion D R, kPa, is produced according to the formula (4), where the coefficient Z participation of suspended dust in the explosion is calculated by the formula

Z = 0,5 F, (14)

where F- mass fraction of dust particles with a size less than the critical one, above which the air suspension becomes explosion-proof, i.e. incapable of spreading flames. In the absence of the possibility of obtaining information to estimate the value Z allowed to take Z = 0,5.

18. Estimated mass of dust suspended in the volume of the room m, kg, formed as a result of an emergency, is determined by the formula

t = t vz + t av, (15)

where t vz - calculated mass of swirling dust, kg;

t av - Estimated mass of dust entering the room as a result of an emergency, kg.

19. Estimated mass of swirling dust m vz is determined by the formula

t vz \u003d K vz t p, (16)

where K vz- the proportion of dust deposited in the room, capable of moving into a suspended state as a result of an emergency. In the absence of experimental data on the value K vz allowed to assume K vz = 0,9;

t p- the mass of dust deposited in the room by the time of the accident, kg.

20. Estimated mass of dust entering the room as a result of an emergency, m av, is determined by the formula

t av = (t up + q T)K p, (17)

where t up- mass of combustible dust emitted into the room from the apparatus, kg;

q- the productivity with which the flow of dust-like substances into the emergency apparatus through pipelines continues until they are turned off, kg×s -1 ;

T - shutdown time, determined according to clause 7 c), s;

K p- dusting coefficient, representing the ratio of the mass of dust suspended in the air to the entire mass of dust that came from the apparatus into the room. In the absence of experimental data on the value K p allowed to assume:

for dusts with a dispersion of at least 350 microns - K p = 0,5;

for dusts with dispersion less than 350 microns - K p = 1,0.

Value t up accepted in accordance with paragraphs. 6 and 8.

21. The mass of dust deposited in the room by the time of the accident is determined by the formula

(18)

where K G - share of combustible dust in the total mass of dust deposits;

t 1 - the mass of dust deposited on hard-to-clean surfaces in the room during the period of time between general cleanings, kg;

t 2- the mass of dust deposited on surfaces accessible for cleaning in the room for the period of time between current cleanings, kg;

K y¾ dust collection efficiency factor. Accepted for manual dusting:

dry - 0.6;

wet - 0.7.

With mechanized vacuum cleaning:

the floor is flat - 0.9;

floor with potholes (up to 5% of the area) - 0.7.

Hard-to-reach areas for cleaning mean such surfaces in industrial premises, the cleaning of which is carried out only during general dust collection. Places available for cleaning are surfaces, dust from which is removed during ongoing dust collection (every shift, daily, etc.).

22. Mass of dust m i (i= 1.2), settling on various surfaces in the room during the inter-harvest period, is determined by the formula

m i = M i (1 - a)b i, (i = 1,2) (19)

where M 1 = - the mass of dust released into the volume of the room over the period of time between general dust collections, kg;

M 1 j

M 2 = - the mass of dust released into the volume of the room over the period of time between current dust collections, kg;

M 2 j- mass of dust emitted by a unit of dust-producing equipment for the specified period, kg;

a- the proportion of dust released into the volume of the room, which is removed by exhaust ventilation systems. In the absence of experimental data on the value a believe a = 0;

b 1, b 2¾ of the share of dust released into the volume of the room, settling, respectively, on the hard-to-reach and accessible surfaces of the room for cleaning ( b 1 + b 2 = 1).

In the absence of information about the value of the coefficients b 1 and b 2, it is allowed to assume b 1 = 1, b 2 =0.

23. Magnitude M i (i= 1.2) can also be determined experimentally (or by analogy with existing production models) during the period of maximum equipment load according to the formula

M i = , (i = 1,2) (20)

where G 1 j , G 2 j - the intensity of dust deposits, respectively, on hard-to-reach F 1 j(m 2) and available F 2 j(m 2) areas, kg × m -2 s -1;

t1, t2- the time interval, respectively, between the general and current dust collections, s.

24. The determination of the fire hazardous category of the premises is carried out by comparing the maximum value of the specific temporary fire load (hereinafter referred to as the fire load) in any of the sections with the value of the specific fire load given in Table. 4.

Table 4

25. With a fire load that includes various combinations (mixtures) of combustible, slow-burning liquids, solid combustible and slow-burning substances and materials within the fire hazardous area, fire load Q, MJ, is determined by the formula

(21)

where G i - number i-th fire load material, kg;

- net calorific value i-th fire load material, MJ×kg -1 .

where S- fire load placement area, m 2 (but not less than 10 m 2).

In rooms of categories B1 - B4, it is allowed to have several sections with a fire load not exceeding the values ​​\u200b\u200bgiven in Table. 4. In rooms of category B4, the distances between these sections should be more extreme. In table. 5 shows the recommended values ​​​​of the limiting distances l pr depending on the value of the critical density of the incident radiant fluxes q cr, kW/m -2 , for a fire load consisting of solid combustible and slow-burning materials. Values l pr given in Table. 5 are recommended provided that H> 11 m; if H < 11 м, то предельное расстояние определяется как l = l pr + (11 - H), where l pr- is determined from the table. 5, H- minimum distance from the surface of the fire load to the lower belt of floor trusses (covering), m.

Table 5

Values q cr for some fire load materials are given in Table. 6.

Table 6

If the fire load consists of different materials, then the value q cr determined by the material with minimum value q cr.

For fire load materials with unknown values q cr distance limit values ​​are accepted l pr³ 12 m.

For a fire load consisting of flammable liquid or combustible liquid, the recommended distance l pr between adjacent areas of placement (spill) of fire load is calculated by the formulas

l pr³ 15 m at H³ 11, (23)

l pr³ 26 -H at H < 11. (24)

If, when determining categories B2 or B3, the amount of fire load Q, determined by formula 21, corresponds to the inequality

Q³ 0.64 g T H 2

Determination of excess explosion pressure for substances and materials capable of exploding and burning when interacting with water, atmospheric oxygen or with each other

26. Calculated explosion overpressure D R for substances and materials capable of exploding and burning when interacting with water, atmospheric oxygen or with each other, is determined according to the above method, assuming Z= 1 and taking as the quantity N T the energy released during the interaction (taking into account the combustion of the interaction products to final compounds), or experimentally in full-scale tests. In the case when to determine the value of D R is not possible, it should be taken as exceeding 5 kPa.

Determination of excess explosion pressure for explosive mixtures containing combustible gases (vapors) and dust

27. Estimated overpressure of explosion D R for hybrid explosive mixtures containing combustible gases (vapors) and dust, is determined by the formula

DP = DP 1 + DP 2, (25)

where DP 1- explosion pressure calculated for combustible gas (steam) in accordance with paragraphs. 10 and 11.

DP 2- explosion pressure calculated for combustible dust in accordance with clause 17.

28. A building belongs to category A if the total area of ​​the premises of category A in it exceeds 5% of the area of ​​all premises or 200 m 2.

It is allowed not to classify a building as category A if the total area of ​​category A rooms in the building does not exceed 25% of the total area of ​​​​all rooms located in it (but not more than 1000 m 2) and these rooms are equipped with automatic fire extinguishing installations.

29. A building belongs to category B if two conditions are met simultaneously:

the building does not belong to category A;

the total area of ​​premises of categories A and B exceeds 5% of the total area of ​​all premises or 200 m2.

It is allowed not to classify a building as category B if the total area of ​​the premises of categories A and B in the building does not exceed 25% of the total area of ​​all premises located in it (but not more than 1000 m 2) and these premises are equipped with automatic fire extinguishing installations.

30. A building belongs to category B if two conditions are met simultaneously:

the total area of ​​premises of categories A, B and C exceeds 5% (10% if there are no premises of categories A and B in the building) of the total area of ​​all premises.

It is allowed not to classify a building as category C if the total area of ​​the premises of categories A, B and C in the building does not exceed 25% of the total area of ​​all premises located in it (but not more than 3500 m 2) and these premises are equipped with automatic fire extinguishing installations.

31. A building belongs to category D if two conditions are met simultaneously:

the total area of ​​premises of categories A, B, C and D exceeds 5% of the total area of ​​all premises.

It is allowed not to attribute knowledge to category D if the total area of ​​​​rooms of categories A, B, C and D in the building does not exceed 25% of the total area of ​​\u200b\u200ball rooms located in it (but not more than 5000 m 2) and rooms of categories A, B, C are equipped automatic fire extinguishing installations.

32. A building belongs to category D if it does not belong to categories A, B, C or D.

34. Determining the categories of outdoor installations should be carried out by sequentially checking their belonging to the categories given in Table. 7, from the highest ( A n) to lower ( D n).

35. If, due to lack of data, it is not possible to estimate the magnitude of an individual risk, the following criteria may be used instead.

Table 7

The horizontal size of the zone limiting gas-vapor-air mixtures with a fuel concentration above the lower concentration limit of flame propagation (LEL) exceeds 30 m (this criterion applies only to combustible gases and vapors) and / or the calculated overpressure during combustion of a gas, vapor or dust-air mixture at a distance of 30 m from the outdoor installation exceeds 5 kPa.

Intensity of thermal radiation from the source of fire of substances and / or materials specified for the category V n, at a distance of 30 m from the outdoor installation exceeds 4 kW / m 2.

6. METHODS FOR CALCULATION OF FIRE HAZARD CRITERIA FOR OUTDOOR INSTALLATIONS

METHOD FOR CALCULATION OF FIRE HAZARD CRITERIA FOR COMBUSTIBLE GAS AND VAPOR

Selection and justification of the design option

36. The choice of the calculation option should be carried out taking into account the annual frequency of implementation and the consequences of certain emergency situations. The accident scenario for which the product of the annual frequency of implementation of this scenario Qw and design overpressure D R during the combustion of gas-vapor-air mixtures in the case of the implementation of the specified option as much as possible, that is:

G = Qw× D P= max. (26)

Value Calculation G produced as follows:

a) various accident scenarios are considered and are determined from statistical data or on the basis of the annual frequency of accidents with the combustion of gas-vapor-air mixtures Qwi for these options;

b) for each of the options under consideration, the values ​​of the calculated overpressure D Pi;

c) quantities are calculated G i = Qwi D Pi for each of the considered accident options, among which the option with the highest value is selected G i;

d) as a calculated option for determining the fire hazard criteria, the option is taken in which the value G i maximum. In this case, the amount of combustible gases and vapors released into the atmosphere is calculated based on the considered accident scenario, taking into account paragraphs 38-43.

37. If it is impossible to implement the method described above, the most unfavorable variant of the accident or the period of normal operation of the apparatus should be chosen as the calculation one, in which the largest amount of gases and vapors, the most dangerous in relation to the consequences of combustion of these mixtures, participate in the formation of combustible gas-vapor-air mixtures. In this case, the amount of gases and vapors released into the atmosphere is calculated in accordance with paragraphs 38-43.

38. The amount of incoming substances that can form combustible gas-air or vapor-air mixtures is determined based on the following prerequisites:

a) a design accident occurs in one of the devices in accordance with paragraph 36 or paragraph 37 (depending on which of the approaches to determining the design accident variant is taken as a basis);

b) all the contents of the device enters the surrounding space;

c) there is a simultaneous leakage of substances from the pipelines supplying the apparatus in the forward and reverse flow during the time necessary to turn off the pipelines.

The estimated shutdown time of pipelines is determined in each specific case, based on the actual situation, and should be minimal, taking into account passport data for locking devices, the nature of the process and the type of design accident.

The estimated shutdown time of pipelines should be taken equal to:

The response time of automatic pipeline shutdown systems according to the passport data of the installation, if the probability of failure of the automatic system does not exceed 0.000001 per year or redundancy of its elements is provided (but not more than 120 s);

120 s if the probability of failure of the automation system exceeds 0.000001 per year and redundancy of its elements is not provided;

300 s with manual shutdown.

It is not allowed to use technical means to disconnect pipelines for which the disconnection time exceeds the above values.

The “acting time” and “off time” should be understood as the period of time from the beginning of a possible inflow of a combustible substance from the pipeline (perforation, rupture, change in nominal pressure, etc.) until the complete cessation of the flow of gas or liquid into the surrounding space. High-speed shut-off valves should automatically shut off the gas or liquid supply in the event of a power failure.

In exceptional cases, in accordance with the established procedure, it is allowed to exceed the above values ​​for the shutdown time of pipelines by a special decision of the relevant ministries or departments in agreement with the Gosgortekhnadzor of Russia at the production facilities and enterprises under its control and the Russian Emergencies Ministry;

d) evaporation occurs from the surface of the spilled liquid; the evaporation area when spilling onto a horizontal surface is determined (in the absence of reference or other experimental data), based on the calculation that 1 liter of mixtures and solutions containing 70% or less (by weight) of solvents is spilled over an area of ​​0.10 m 2, and other liquids - by 0.15 m 2;

e) liquids also evaporate from containers operated with an open liquid surface and from freshly painted surfaces;

f) the duration of liquid evaporation is assumed to be equal to the time of its complete evaporation, but not more than 3600 s.

39. Mass of gas m, kg, released into the surrounding space during a design accident, is determined by the formula

m = (Va + V T) r G, (27)

where Va- the volume of gas released from the apparatus, m 3 ;

V T- the volume of gas released from the pipeline, m 3;

r G- gas density, kg×m -3.

Va= 0.01 R one · V, (28)

where R 1 - pressure in the apparatus, kPa;

V- the volume of the apparatus, m 3;

V T = V 1T + V 2T , (29)

where V 1T- the volume of gas that came out of the pipeline before it was turned off, m 3;

V 2T- the volume of gas released from the pipeline after its shutdown, m 3;

V 1T = q× T, (30)

where q- gas flow rate, determined in accordance with the technological regulations, depending on the pressure in the pipeline, its diameter, temperature of the gas medium, etc., m 3 × s -1;

T- time determined according to clause 38, s;

where R 2 - maximum pressure in the pipeline according to the technological regulations, kPa;

r- inner radius of pipelines, m;

L- length of pipelines from the emergency apparatus to the valves, m.

40. Liquid vapor mass m, kg, released into the surrounding space in the presence of several sources of evaporation (the surface of a spilled liquid, the surface with a freshly applied composition, open containers, etc.), is determined from the expression

m = m p + m + m sv .env + m lane, (32)

where m p- mass of liquid evaporated from the spill surface, kg;

m- mass of liquid evaporated from the surfaces of open containers, kg;

m sv .env- mass of liquid evaporated from the surfaces on which the applied composition is applied, kg;

m lane- the mass of the liquid evaporated into the surrounding space in case of its overheating, kg.

In this case, each of the terms ( m p, m, m sv .okp) in formula (32) is determined from the expression

m = W × F and · T, (33)

where W- evaporation rate, kg×s -1 ×m -2; F and- evaporation area, m 2, determined in accordance with clause 38, depending on the mass of the liquid m p, released into the surrounding space; T- the duration of the entry of vapors of flammable and combustible liquids into the surrounding space in accordance with clause 38, p.

the value m lane determined by the formula (at T a > T bale)

(34)

where m p- mass of overheated liquid released, kg;

C p is the specific heat capacity of the liquid at the superheat temperature of the liquid T a, J × kg -1 × K -1 ;

T a- the temperature of the superheated liquid in accordance with the technological regulations in the technological apparatus or equipment, K;

T bale is the normal boiling point of the liquid, K;

L Spanish is the specific heat of vaporization of the liquid at the superheat temperature of the liquid T a, J×kg -1 .

If the emergency situation is associated with the possible ingress of liquid in the atomized state, then it must be taken into account in formula (32) by introducing an additional term that takes into account the total mass of the incoming liquid from the spraying devices, based on the duration of their operation.

41. Weight m P released liquid, kg, is determined in accordance with clause 38.

42. Evaporation rate W is determined by reference and experimental data. For unheated flammable liquids, in the absence of data, it is allowed to calculate W according to the formula

, (35)

where M- molar mass, g×mol -1;

R n- saturated vapor pressure at the design temperature of the liquid, determined from the reference data in accordance with the requirements of clause 3, kPa.

43. For liquefied hydrocarbon gases (LHG), in the absence of data, it is allowed to calculate the specific gravity of the evaporated LHG m sug from the strait, kg × m -2, according to the formula

where M- molar mass of LPG, kg×mol -1;

L Spanish- molar heat of vaporization of LPG at the initial temperature of LPG T w, J×mol -1 ;

T 0 - initial temperature of the material on the surface of which LPG is poured, K;

T w- initial temperature of LPG, K;

l tv- coefficient of thermal conductivity of the material on the surface of which LPG is poured, W × m -1 × K -1;

The coefficient of thermal diffusivity of the material on the surface of which LPG is poured, m 2 × s -1;

WITH tv- heat capacity of the material on the surface of which LPG is poured, J×kg -1 ×K -1 ;

r tv- density of the material on the surface of which LPG is poured, kg×m -3 ;

t- current time, s, taken equal to the time of complete evaporation of LPG, but not more than 3600 s;

Reynolds number;

U - air flow rate, m×s -1 ;

Characteristic size of the LPG strait, m;

v in- kinematic viscosity of air, m 2 × s -1;

l v- coefficient of thermal conductivity of air, W × m -1 × K -1.

Formula 38 is valid for LPG with temperature T w £ T bale. At LPG temperature T w > T bale additionally, the mass of superheated LPG is calculated m lane formula 34.

Calculation of the horizontal dimensions of the zones limiting gas and vapor-air mixtures with a fuel concentration above the LEL, in case of emergency inflow of flammable gases and vapors of unheated flammable liquids into open space

44. Horizontal dimensions of the zone, m, limiting the area of ​​concentrations exceeding the lower concentration limit of flame propagation ( With ncpr), calculated by the formulas:

For combustible gases (GH):

For vapors of unheated flammable liquids (FLL):

,

where m g- the mass of the GG that entered the open space in an emergency, kg;

r G- GG density at design temperature and atmospheric pressure, kg×m -3 ;

m p- the mass of flammable liquid vapors that entered the open space during the time of complete evaporation, but not more than 3600 s, kg;

r P- vapor density of flammable liquids at design temperature and atmospheric pressure, kg×m -3 ;

R n- pressure of saturated vapors of flammable liquids at design temperature, kPa;

TO- coefficient taken equal to TO=T/3600 for flammable;

T- the duration of the entry of flammable liquid vapor into the open space, s;

With ncpr- the lower concentration limit of the propagation of the GG flame or flammable liquid vapors,% (vol.);

M- molar mass, kg×kmol -1;

V 0 - molar volume equal to 22.413 m 3 × kmol -1;

t p- design temperature, °C.

The maximum possible air temperature in the corresponding climatic zone or the maximum possible air temperature according to the technological regulations should be taken as the design temperature, taking into account the possible increase in temperature in an emergency. If such a design temperature value t p for some reason it is not possible to determine, it is allowed to take it equal to 61 ° C.

45. The external dimensions of devices, installations, pipelines, etc. are taken as the origin of the horizontal dimension of the zone. In all cases, the value R ncpr must be at least 0.3 m for GG and flammable liquids.

Calculation of overpressure and momentum of the pressure wave during the combustion of mixtures of combustible gases and vapors with air in open space

46. ​​Based on the considered accident scenario, the mass is determined m, kg, combustible gases and (or) vapors released into the atmosphere from the process apparatus in accordance with paragraphs 38-43.

47. The value of excess pressure D R, kPa, developed during the combustion of gas-vapor-air mixtures, is determined by the formula

, (39)

where R 0 - atmospheric pressure, kPa (allowed to be taken equal to 101 kPa);

r- distance from the geometric center of the gas-vapor-air cloud, m;

m pr- reduced mass of gas or steam, kg, is calculated by the formula

, (40)

where Q sg- specific heat of combustion of gas or steam, J×kg -1 ;

Z is the coefficient of participation of combustible gases and vapors in combustion, which can be taken equal to 0.1;

Q 0 is a constant equal to 4.52×106 J×kg -1 ;

m- mass of combustible gases and (or) vapors released into the environment as a result of the accident, kg.

48. The magnitude of the pressure wave impulse i, Pa×s, calculated by the formula

. (41)

METHOD FOR CALCULATION OF FIRE HAZARD CRITERIA FOR COMBUSTIBLE DUSTS

49. The most unfavorable accident scenario or the period of normal operation of apparatuses, in which the largest amount of substances or materials most dangerous in relation to the consequences of such combustion, is involved in the combustion of the dust-air mixture to determine the fire hazard criteria for combustible dusts.

50. The amount of incoming substances that can form combustible dust-air mixtures is determined based on the premise that at the time of the design accident there was a planned (repair work) or sudden depressurization of one of the technological apparatus, followed by an emergency release into the surrounding space of the dust apparatus.

51. The calculated mass of dust released into the surrounding space during a design accident is determined by the formula

M = M vz + Mav, (42)

where M- the estimated mass of combustible dust entering the surrounding space, kg,

M vz- calculated mass of swirling dust, kg;

Mav- calculated mass of dust received as a result of an emergency, kg.

52. Size M vz is determined by the formula

M vz= K g · K vz · M p, (43)

where K g- share of combustible dust in the total mass of dust deposits;

K vz- the proportion of dust deposited near the apparatus, capable of moving into a suspended state as a result of an emergency. In the absence of experimental data on the value K vz allowed to take K vz = 0,9;

M p- mass of dust deposited near the apparatus by the time of the accident, kg.

53. Magnitude Mav is determined by the formula

Mav= (Map + q· T) · K p, (44)

where Map- mass of combustible dust emitted into the surrounding space during depressurization of the process apparatus, kg; in the absence of engineering devices limiting the release of dust, it should be assumed that at the time of the design accident, an emergency release into the surrounding space of all the dust in the apparatus occurs;

q- performance, with which the flow of dust-like substances into the emergency apparatus through pipelines continues until they are turned off, kg×s -1 ;

T- Estimated shutdown time, s, determined in each specific case, based on the actual situation. It should be taken equal to the response time of the automation system, if the probability of its failure does not exceed 0.000001 per year or redundancy of its elements is provided (but not more than 120 s); 120 s if the probability of failure of the automation system exceeds 0.000001 per year and redundancy of its elements is not provided; 300 s with manual shutdown;

TO P- dusting coefficient, representing the ratio of the mass of dust suspended in air to the entire mass of dust coming from the apparatus. In the absence of experimental data on the value of K P it is allowed to accept: 0.5 - for dusts with a dispersion of at least 350 microns; 1.0 - for dusts with a dispersion of less than 350 microns.

54. Overpressure D R for combustible dusts is calculated as follows:

a) determine the reduced mass of combustible dust m pr, kg, according to the formula

m pr= M · Z · H t/H then, (45)

where M is the mass of combustible dust released into the environment as a result of the accident, kg;

Z- coefficient of participation of dust in combustion, the value of which can be taken equal to 0.1. In certain justified cases, the value Z can be reduced, but not less than 0.02;

H t- calorific value of dust, J×kg -1 ;

H then- constant taken equal to 4.6 106 J×kg -1 ;

b) calculate the calculated overpressure D R, kPa, according to the formula

, (46)

where r- distance from the center of the dusty cloud, m. It is allowed to count the value r from the geometric center process plant;

R 0 - atmospheric pressure, kPa.

55. The magnitude of the pressure wave impulse i, Pa s, is calculated by the formula

. (47)

METHOD FOR CALCULATION OF THERMAL RADIATION INTENSITY

56. The intensity of thermal radiation is calculated for two fire cases (or for one of them that can be implemented in this process unit):

Fire spills of flammable liquids, combustible liquids or combustion of solid combustible materials (including dust combustion);

- "fireball" - large-scale diffusion combustion, realized when a tank with a flammable liquid or gas under pressure bursts with ignition of the contents of the tank.

If both cases are possible, then when evaluating the values ​​of the fire hazard criterion, the largest of the two values ​​of the intensity of thermal radiation is taken into account.

57. The intensity of thermal radiation q, kW m -2 , for a fire spilling liquid or burning solid materials is calculated by the formula

q = E f · Fq t, (48)

where E f- average surface density of thermal radiation of the flame, kW m -2 ;

Fq- angular coefficient of irradiance;

t is the transmittance of the atmosphere.

Meaning E f is taken on the basis of the available experimental data. For some liquid hydrocarbon fuels, these data are given in Table. eight.

In the absence of data, it is allowed to take the value E f equal to: 100 kW×m -2 for LPG, 40 kW×m -2 for petroleum products, 40 kW×m -2 for solid materials.

Table 8

The average surface density of the thermal radiation of the flame depending on the diameter of the source and the specific mass burn-up rate for some liquid hydrocarbon fuels

Calculate the effective diameter of the strait d, m, according to the formula

where F Strait area, m 2.

Calculate the height of the flame H, m, according to the formula

, (50)

where M- specific mass fuel burnout rate, kg×m -2 ×s -1 ;

r V- ambient air density, kg×m -3 ;

g= 9.81 m×s -2 - free fall acceleration.

(59)

where H- height of the center of the “fireball”, m;

Ds- effective diameter of the “fireball”, m;

r- distance from the irradiated object to a point on the earth's surface directly under the center of the "fireball", m.

Effective fireball diameter Ds determined by the formula

Ds= 5,33 m 0,327 , (60)

where m- mass of combustible substance, kg.

the value H determined in the course of special studies. It is allowed to take the value H equal Ds/2.

Lifetime of the "fireball" t s, s, is determined by the formula

t s= 0,92m 0,303 . (61)

The atmospheric transmittance t is calculated by the formula

7. INDIVIDUAL RISK ASSESSMENT METHOD

59. This method is applicable for calculating the value of an individual risk (hereinafter referred to as the risk) at outdoor installations in the event of such damaging factors as overpressure developed during the combustion of gas, vapor or dust-air mixtures, and thermal radiation during the combustion of substances and materials .

60. The amount of individual risk R B when burning gas, steam or dusty air mixtures, they are calculated by the formula

(63)

where Q Bi- annual frequency of occurrence i-th accident with combustion of gas, steam or dusty air mixture at the considered outdoor unit, 1/year;

Q BP i- conditional probability of damage to a person located at a given distance from the outdoor unit, excessive pressure in the implementation of the specified accident i-th type;

n

Q values Bi determined from statistical data or on the basis of methods set forth in regulatory documents approved in the prescribed manner. In formula (63), it is allowed to take into account only one most unfavorable accident, the value Q B for which is assumed to be equal to the annual frequency of occurrence of a fire with combustion of gas, vapor or dust-air mixtures at an outdoor installation according to regulatory documents approved in the prescribed manner, and the value of Q BP calculated based on the mass of combustible substances released into the atmosphere, in accordance with paragraphs. 37-43.

61. The amount of individual risk R P with the possible combustion of substances and materials listed in Table 7 for the category V n, calculated by the formula

, (64)

where Q fi is the annual frequency of fire occurrence at the considered outdoor installation in the event of an accident i th type, 1/year;

Q fПi- conditional probability of damage to a person located at a given distance from the outdoor installation by thermal radiation during the implementation of an accident i-th type;

n- number of types of accidents under consideration.

Q value fi determined from statistical data or on the basis of methods set forth in regulatory documents approved in the prescribed manner.

In formula (64), it is allowed to take into account only one most unfavorable accident, the value of Q f for which is assumed to be equal to the annual frequency of fire occurrence at an outdoor installation according to regulatory documents approved in the prescribed manner, and the value of Q fp calculated based on the mass of combustible substances released into the atmosphere, in accordance with paragraphs 37-43.

62. Conditional probability Q BPi damage to a person by excessive pressure during the combustion of gas, steam or dusty air mixtures at a distance r from the epicenter is determined as follows:

Calculate the excess pressure D R and momentum i according to the methods described in Section 6 (methods for calculating the values ​​of fire hazard criteria for combustible gases and vapors or the method for calculating the values ​​of fire hazard criteria for combustible dusts);

Based on the values ​​of D R and i, calculate the “pierced” value - functions R r according to the formula

R r = 5 - 0.26 ln(V), (65)

(66)

where D R- excess pressure, Pa;

i- pressure wave impulse, Pa×s;

With the help of Table. 9 determine the conditional probability of human injury. For example, with the value R r= 2.95 value Q VP= 2% = 0.02, and at R r= 8.09 value Q VP= 99,9 % = 0,999.

63. Conditional probability of damage to a person by thermal radiation Q fpi defined as follows:

a) calculate the value Pr according to the formula

Pr = -14,9 + 2,56 ln (t · q 1,33), (67)

where t- effective exposure time, s;

q- intensity of thermal radiation, kW×m -2, determined in accordance with the method for calculating the intensity of thermal radiation (section 6).

the value t find:

1) for fires of flammable liquids, combustible liquids and solid materials

t = t 0 + X/u, (68)

where t 0 - characteristic time of fire detection, s, (it is allowed to take t= 5 s);

X- distance from the person's location to the area where the intensity of thermal radiation does not exceed 4 kW × m -2, m;

u- the speed of a person, m × s -1 (it is allowed to take u= 5 m×s -1);

2) for the effect of a “fireball” - in accordance with the method for calculating the intensity of thermal radiation (section 6);

b) using the table. 9 determine the conditional probability Q pi damage to humans by thermal radiation.

64. If both a spill fire and a “fireball” are possible for the process plant under consideration, both of the above types of accident should be taken into account in formula (64).

Table 9

The values ​​of the conditional probability of human injury depending on the value of Pr

CALCULATED DETERMINATION OF THE COEFFICIENT VALUE Z PARTICIPATION OF COMBUSTIBLE GASES AND VAPOR OF UNHEATED FLAMMABLE LIQUIDS IN THE EXPLOSION

, (3)

with air mobility for combustible gases

, (4)

in the absence of air mobility for vapors of flammable liquids

, (5)

with air mobility for vapors of flammable liquids

, (6)

T - the mass of gas or vapors of flammable liquids entering the volume of the room in accordance with Sec. 3, kg;

d- permissible deviations of concentration at a given level of significance Q (WITH> ) given in Table P1 ;

X lep, Y lep, Z lep ¾ axle distances X, Y and Z from the source of gas or steam, limited by the lower concentration limit of flame propagation, respectively, m; calculated according to the formulas (10 - 12) of the application;

L, S- length and width of the room, m;

F- floor area of ​​the room, m 2;

U- air mobility, m×s -1 ;

C n- concentration of saturated vapors at design temperature tp, °С, indoor air, % (vol.).

Concentration C n can be found by the formula

where R n - saturated vapor pressure at design temperature (found from reference literature), kPa;

R 0 - atmospheric pressure equal to 101 kPa.

Table 1

Significance level value Q (WITH> ) is selected based on the characteristics of the technological process. Allowed to take Q (WITH> ) equal to 0.05.

2. The value of the coefficient Z the participation of vapors of flammable liquids in an explosion can be determined from the graph shown in the figure.

Values X are determined by the formula

(8)

where WITH* - value given by the ratio

WITH* = j C st, (9)

where j- effective coefficient of excess fuel, taken equal to 1.9.

3. Distances X NKPR, Y NKPR and Z ncpr are calculated according to the formulas:

; (10)

; (11)

; (12)

where K 1 - coefficient taken equal to 1.1314 for combustible gases and 1.1958 for flammable liquids;

K 2 - coefficient taken equal to 1 for combustible gases and K2 = T/3600 for flammable liquids;

K 3 - coefficient taken equal to 0.0253 for combustible gases in the absence of air mobility; 0.02828 for combustible gases with air mobility; 0.04714 for flammable liquids in the absence of air mobility and 0.3536 for flammable liquids with air mobility;

H ¾ room height, m.

For negative values ​​of the logarithms of the distance X NKPR, Y NKPR and Z ncpr are taken equal to 0.

According to Federal Law No. 123-FZ, RF PPB and SP, the fire hazard category must be established for strictly defined objects. In "SpetsPozhAudit" formed low price for services in the calculation of this category. The category should be determined and established for warehouse and industrial purpose. Why is it necessary to classify individual premises, as well as industrial buildings and warehouse buildings for fire and explosion hazard?

The purpose of the classification is to establish strict but reasonable requirements for fire and explosion safety for specific objects: premises of warehouse complexes, transport organizations, manufacturing, mining and processing enterprises.

Fire safety requirements are mainly aimed at preventing the very possibility of a fire. In addition, the task of fire safety includes providing fire protection for employees of these enterprises, as well as protecting property in the event of a fire in warehouses, production workshops and other premises. Prevention of fires and explosions at warehouse and industrial facilities are united by one concept - fire and explosion prevention.

Calculation of the fire hazard category

1. Categories "A" and "B"

When applying the assessment of objects classified as "A-B", the most negative option is chosen as the basis. This approach is due to the desire of the authorities to prevent large-scale disasters. Owners and officials are obliged to take measures aimed at preventing the most serious consequences of the accident. Experts determine the maximum number of harmful factors that can affect environment, objects and people. If it is impossible to simulate an emergency situation by calculation, the expert is obliged to use the appropriate laboratory data. The main requirement for such calculations is objectivity. The appendix of the order contains formulas for determining excess pressure, emissions, as well as a number of coefficients.

2. Other categories

The methodology is to carry out comparative analysis limit load of any of the sections of the object with indicators of a special table. A specialist calculates the category of fire hazard based on indicators of limiting distances, pressure of media (dust, gases, liquids). The characteristics of the materials are also taken into account. Appendix B to Order 182 includes several tables with coefficients for calculations at once.

The choice of method directly depends on the degree of risk. Before starting the study, experts are required to verify the data on the object with the characteristics of the table of categories.

The assessment is carried out according to the following criteria:

• the quantity and properties of gaseous, liquid or solid substances in the room;
• indicators of pressure, humidity and temperature of the environment;
• number of storeys of the building, area, configuration;
• features of building and finishing materials.

Upon completion of the work, specialists submit a detailed report with graphs, tables and diagrams. The document must contain references to the methodological and reference materials used.

Category of premises for fire and explosion hazards according to the Code of Practice

In accordance with the requirements of SP 12.13130.2009 and other legal documents the category of premises for fire hazard is determined depending on the characteristics of substances and materials located (received, dispensed, stored, processed, transported) in warehouses and industrial premises. This Code of Rules establishes methods for determining the characteristics by which buildings and premises for storage and production purposes are classified into explosion and fire hazard categories.

According to the list of terms adopted in the Code of Practice, the category of explosion and fire hazard is defined as a classification characteristic of the fire and / or explosion hazard of an object (building, premises, outdoor installation). The categorization of premises (buildings, outdoor installations and structures) according to explosion and fire hazard is one of the fire prevention measures that should be given priority.

According to paragraph 1 of article 27 of chapter 8 federal law No. 123-FZ dated July 22, 2008 and Code of Practice No. 12.13130.2009, production and storage facilities are divided into five categories:

• category "A" - increased explosion and fire hazard,
• category "B" - fire and explosion hazard,
• category "B" - fire hazard (subcategories from B1 to B4 are established in this category),
• category "G" - moderate fire hazard,
• category "D" - reduced fire hazard.

Room classification methods

The determination of the category of explosion and fire hazard of each room (warehouse, workshop, laboratory and other premises) should be carried out by methodically checking these rooms for belonging to each of the categories, starting with the most dangerous category "A", ending with the least dangerous - "D".

The Code of Rules 12.13130.2009 contains tables that determine the category of various premises for fire and explosion hazards. In addition, the SP contains mandatory and recommended annexes that serve as a guide to determining whether a room belongs to a particular category.

The appendix to the Code of Rules provides methods for determining the category of premises and other practical advice. In particular, to determine the categories of premises of increased explosion and fire hazard (category A) and fire and explosion hazard (category B), you should use Appendix "A".

By order of the Ministry of Emergency Situations of Russia, amendments were made to the joint venture, relating, in particular, to Annex "A". V new edition This appendix provides for the possibility of determining the criteria for the explosion and fire hazard of a room based on the results of research work (provided that it is impossible to use calculation methods). Research papers must be properly coordinated.

Substances and materials for which the explosion and fire hazard category of premises and buildings is determined

As mentioned above, the category of premises for explosion and fire hazard depends, in particular, on the type, quantity and characteristics of substances and materials stored, processed and transported in these premises. Let us consider in detail what gases, liquids and materials can affect the definition of the category of explosion and fire hazard of warehouse and industrial premises. This list is by no means exhaustive, only General characteristics substances and materials.

It should be noted that the definition of the category of buildings in terms of fire hazard is based on the share and total area of ​​the premises located in this building (structure) and assigned to one or another category of explosion and fire hazard.

Category "A"

"A" - the highest category of explosion and fire hazard of premises. The objects of category "A" should include premises in which flammable gases and flammable liquids with t? flashes not exceeding 28 C in such an amount that these gases and liquids can form explosive vapor-gas-air mixtures.

An additional condition for classifying premises as category “A” is that when these vapor-gas-air mixtures are ignited, an excess explosion pressure exceeding 5 kPa may develop. If substances and/or materials capable of igniting, exploding and burning in contact with water, oxygen and in interaction with each other are handled (accepted for storage, measured, dispensed, processed and transported) in the premises, an excess explosion pressure of more than 5 kPa, then such a room is also classified as category "A".

Technological processes in production

To determine the category of premises for industrial purposes, one should take into account not only the properties of the substances and materials being handled, but also the nature of the technological process during which these flammable and combustible gases, liquids and materials are used (processed, measured, burned, transported, etc.).

Technological operations associated with the circulation of flammable and combustible liquids and materials have their own special hazards. Due to the possibility of the formation of a combustible vapor-air mixture, the most fire and explosion hazards are those operations that are associated with the storage, transportation and unloading/filling of flammable liquids and combustible liquids.

Category "B"

The category "B" will include premises in which combustible dusts, fibers, flammable liquids with t? flashes above 28?С, as well as GZH in an amount sufficient to form extremely dangerous dust or vapor-air mixtures, when ignited, an excess explosion pressure of more than 5 kPa can develop. First, the possibility of classifying the premises as category “A” is being explored. In the absence of reasons why this room could be classified as category "A", it is examined for belonging to the "lighter" categories: from "B" to "D".

Categories B1 - B4

• space-planning characteristics of the studied premises;
• type and quantity of combustible substances and materials;
• characteristics of technological processes carried out in the premises;
• the quantity and nature of the placement of the fire load (PN);
• specific fire hazard properties inherent in combustible substances and materials placed in the room and constituting the fire load.

The fire load is understood as the amount of heat that can be released in the room in the event of a fire. Spetsproject Group LLC performs calculation of categories of premises, as well as buildings and structures for explosion and fire hazard. This service provided to customers by experienced professionals who are competent in this particular area. Classification of buildings and structures according to fire hazard is carried out in the case when these buildings and structures have at least one categorized room.

Categories "G" and "D"

Category "G" is assigned to premises containing non-combustible substances and materials whose temperature is significantly higher than normal (that is, in a hot, red-hot or molten state), and the processing of which is associated with the release of sparks and flames. At the same time, this category includes premises in which liquid liquids, combustible gases and solids, which serve as fuel raw materials, are circulated.

The procedure for determining the hazard category of outdoor installations

According to regulatory documents, outdoor installations are subject to categorization, including structures that are not structurally buildings. For the classification of outdoor installations, five categories of explosion and fire hazard are accepted:

• "AN" - increased explosion and fire hazard of outdoor installations,
• "BN" - explosion and fire hazard,
• "VN" - fire hazard,
• "GN" - moderate fire hazard,
• "DN" - reduced fire hazard.

• fire hazardous properties of combustible substances and materials in these installations;
• quantities of combustible substances and materials;
• features of technological processes.

Methods for calculating the fire hazard criteria for various outdoor installations are prescribed in Appendix "B", which is mandatory. The appendix contains formulas and definitions of the quantities included in the calculation formulas.

Categories AN and BN

The first category of increased explosion and fire hazard - category "AN" - is assigned to outdoor installations in which combustible gases and flammable liquids are stored (transported, processed), provided that the flash point of these gases and liquids does not exceed 28 ° C.

In addition, the category "AN" includes installations in which there are substances and / or materials that can burn in the open air (when interacting with atmospheric oxygen), as well as in contact with water or between themselves.

Category "BN" explosion and fire hazard is assigned to outdoor installations in which combustible fibers and / or combustible dusts, flammable liquids with a flash point above 28 C are stored (processed, transported, present). Under certain conditions, combustible liquids belong to this category.

VN category

Storage, processing or transportation in outdoor installations of flammable and / or slow-burning liquids allows these installations to be classified as “HV”. This category also includes outdoor installations in which solid combustible and / or slow-burning materials (in particular dust and fibers) are present, provided that they burn when interacting with water, atmospheric oxygen and with each other.

First, the possibility of assigning outdoor installations containing these substances and materials to the category "AN" or "BN" is considered. In addition, in order to attribute these substances and materials to the first two categories (increased explosion and fire hazard and fire and explosion hazard), one condition must be met.

Outdoor installations should be assigned to categories "AN" or "BN" in cases where the magnitude of the fire risk with the possible combustion of flammable and / or slow-burning liquids, combustible and / or slow-burning materials exceeds one millionth per year at a distance of up to 30 m from these outdoor installations .

One of the factors that determine the explosion and fire hazard of outdoor installations is the potential for the formation of a combustible environment both directly inside these installations and outside them, especially when performing various technological operations.

Categories GN and DN

An outdoor installation must be classified in terms of fire hazard to the “GN” category, in the case when it contains non-combustible substances and / or materials in a molten / hot / red-hot state, and the process of processing these substances and / or materials is accompanied by the release of sparks, flames and /or radiant heat. The word "present" should be understood as storage, processing and transportation of substances and materials.

This category also includes outdoor installations in which there are (placed, released, stored, processed, transported) combustible gases and liquids, as well as solids intended for disposal as fuel.

Finally, the "lightest" category - DN - reduced fire hazard, which is assigned to outdoor installations in which there are non-combustible substances and / or materials in a cold state. At the same time, outdoor installations must be checked for the possibility of assigning them to higher categories of AN, BN, VN or GN.

Additional options for establishing the fire and explosion category of outdoor installations

Calculation of the probability of hitting a person

When calculating the probability (we are talking about the conditional probability) of hitting people, one should be guided by the mandatory Appendix D, which presents an effective method for calculating this indicator. When determining the conditional probability of hitting people, various hazards are taken into account, including the impact of combustion products of steam and gas-air mixtures, thermal radiation in the event of combustion of spills of flammable liquid substances, as well as other factors. Features of calculating the conditional probability of hitting people are described in detail in this section of the Code of Practice.

What affects the fire safety category when designing an object

When designing production and storage facilities, it is necessary to have enclosing structures, the fire resistance limit of which will correspond to the design category of the premises (building, structure and external installation) in terms of fire and explosion hazard.

Depending on the category, the need for fire-resistant fire-resistant windows and doors is also determined. In addition, taking into account the category, the time required for the evacuation of people is calculated and the location of the evacuation routes and their length are determined. The number of emergency exits, the size of the fire distances between outdoor installations and buildings are also determined when designing by the calculation method, taking into account the category assigned to the object.

Conclusion

The calculation and establishment of categories of premises and buildings is carried out in accordance with the above regulatory documents, as well as on the basis of specially developed departmental norms for technological design.

During the operation of the building a separate room or outdoor installation are based primarily on its explosion and/or fire hazard category. The need for installation of fire alarms and equipping these facilities with fire extinguishing equipment of one type or another depends on the explosion and fire hazard category of premises, buildings (structures) and outdoor installations.

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SAND FOR CONSTRUCTION WORKS

TECHNICAL CONDITIONS

GOST 8736-85

Official edition

USSR STATE COMMITTEE FOR CONSTRUCTION Moscow

DEVELOPED by the Ministry of Industry building materials the USSR

PERFORMERS

M. L. Nisnevmch, Dr. Sc. sciences; N. S. Levkova, Ph.D. tech. sciences; M. I. Lopatnikov, Ph.D. geogr. sciences; E. I. Anisimova, Ph.D. tech. sciences; A. T. Bukengolts, I. M. Poltiiina, V. M. Yumashev, Ph.D. tech. sciences; A. I. Polyakova, V. A. Bogoslovsky

INTRODUCED by the Ministry of Industry of Building Materials of the USSR

Deputy Minister V. Ya. Sidorov

APPROVED AND INTRODUCED BY Decree State Committee USSR on construction matters dated September 13, 1985 No. 146

GOST 8736-85 Page 9

the upper and lower limits, and the sand is classified in terms of size to the lower of the adjacent groups.

The security of the standard values ​​for the content of grains with a size of less than 0.16 mm, as well as the content of dust and clay particles during acceptance control should be at least 97.5% for enriched sand of all types of the highest quality category, 95% for enriched sand of all types of the first quality category, 90% for natural sands and from screenings of crushing.

2.7. The availability of the values ​​of the sand fineness module established by the standard is characterized by the ratio of the number of replacement samples, the fineness modulus of which is within the upper and lower standard values ​​for a given group of sands, to the total number of replacement samples taken and tested during one quarter.

The availability of the standard values ​​for the content of grains less than 0.16 mm in size in sands, as well as dust-like and clay particles, is characterized by the ratio of the number of replacement samples, the quality indicators of which do not exceed the standard values, to the total number of replacement samples taken and tested during one quarter. At the same time, the provision of the content of grains with a size of less than 0.16 mm, as well as dust and clay particles in enriched sands of the highest quality category, established by the standard, is determined on the basis of statistical control in accordance with the mandatory Appendix 2.

2.8. For allowed paragraphs. 2.6 and 2.7 of the number of replacement samples that have deviations from the regulatory requirements, the value of this deviation should not exceed 20%.

2.9. When checking the compliance of sand with the requirements of this standard, the consumer must apply the sampling procedure given in paragraphs. 2.11-2.13. If the results of the control check on the grain composition and the content of dust and clay particles are unsatisfactory, the batch of sand is not accepted.

2.10. The number of point (partial) samples taken for the control check of the quality of sand in each batch must be at least as indicated below.

Batch volume, m 3

point

St. 350 to 700 15

Point samples are combined into an average sample characterizing the controlled lot.

UDC 691.223: 006.354 Group Zh17

STATE STANDARD OF THE UNION OF THE SSR

SAND FOR CONSTRUCTION WORKS

Specifications

Sand for construction works. Specifications

Instead of GOST 8736-77

The Decree of the State Committee of the USSR for Construction of September 13, 1965 No. 146 established the deadline for the introduction

Non-compliance with the standard is punishable by law

This standard applies to natural sand and sand from crushing screenings with an average grain density, including pores (bulk density) over 2000 kg / m 3, obtained from specially or incidentally mined rocks and waste from mining and processing enterprises and used as aggregates for all types of concrete and mortars, as well as pavement and other construction works.

Sand made according to this standard must be used in accordance with the current regulatory and technical documents.

Explanations of terms used in this standard are given in help application 1.

1. TECHNICAL REQUIREMENTS

1.2. Sand is divided into the following types:

natural and enriched;

from crushing screenings and enriched from crushing screenings. It is allowed to supply a mixture of natural sands and from screenings of crushing.

Official edition

Reprint prohibited

© Standards Publishing, 1986

Page 2 GOST 8736-85

1.3. By agreement of the enterprise (quarry)-manufacturer with the consumer, crushed and fractionated sands are supplied, the requirements for which are established in the technical conditions approved in the prescribed manner.

1.4. Sand should be characterized by the following quality indicators:

grain composition;

1.5. Sand from crushing screenings is also characterized by the ultimate strength of the original rock during compression in a water-saturated state.

The enterprise (quarry)-manufacturer of natural and enriched sands must have and report to the consumer at his request the following characteristics established during geological exploration in accordance with GOST 24100-80 :

mineralogical and petrographic composition indicating rocks and minerals classified as harmful impurities;

indicator of the potential-reactivity of sand, determined by the chemical method (if there are reactive minerals and rocks in the sand);

description of the shape and nature of the surface of sand grains;

average density of sand grains.

If during geological exploration, at the request of the customer, additional characteristics of sands were determined according to GOST 24100-80: voidness, specific surface area,

filtration coefficient, they must also be reported to the consumer at his request.

The enterprise (quarry)-manufacturer of sand from crushing screenings must have and report to the consumer, at his request, the petrographic characteristics and indicators of the physical and mechanical properties of the original rock, established during geological exploration in accordance with GOST 23845-79.

1.6. Grain composition

1.6.1. Sands natural and from screenings of crushing, depending

from the grain composition are divided into groups: increased

sizes, large, medium, small and very small.

1.6.2. Enriched sand depending on the grain composition

subdivided into groups: increased size, large, medium and small. Enriched sand from crushing screenings, depending on the grain composition, is divided into groups:

high size, large and medium.

1.6.3. For each group of sands: natural and from screenings of crushing, enriched and enriched from screenings of crushing

GOST 6736-85 Page 3

after preliminary sieving them on a sieve with holes of 5 mm in size to isolate grains of gravel (crushed stone), the sand size module M k and the total residue on a sieve with mesh No. 063 according to GOST 3584-73 must correspond to those indicated in Table. one.

Table 1

If, when determining the group of sand, it corresponds to one group according to the size modulus, and to another group according to the total residue on sieve No. 063, then the sand group is determined according to the size modulus.

In this case, the deviation of the value of the total residue on sieve No. 063 from that indicated in the table is indicated in the passport. 1 for the sand of this group.

Notes: 1. By agreement of the parties, it is allowed to supply sand with a fineness modulus over 3.5.

2. Very fine sand with a particle size modulus of 1.0 to 1.5 is supplied only by order of consumers for use in plaster mortars, as well as for use in a mixture with a coarsening additive as fine aggregates for concrete in areas where there are no sand deposits with fineness modulus over 1.5,

1.6.4. As fine aggregates for concrete, natural and enriched sands, sands from crushing screenings and enriched from crushing screenings of increased size, large, medium and fine, with a particle size modulus from 1.5 to 3, should be supplied and used in accordance with the requirements of GOST 10268-80, 25.

The grain composition of the fine aggregate should be as specified below.

Hole size ■control sieve, mm

Passage through a sieve JVb 016 Fineness modulus

Total residues on control sieves, % by weight

20-70 . 35-90 . 90-100 . 10-0 . 1,5-3,25

In this case, only grains passing through a sieve with round holes with a diameter of 5 mm are taken into account.

The use of sand from crushing screenings and enriched sand from crushing screenings and their mixtures with natural fine and very fine sands as fine aggregates is allowed provided that the specified workability is ensured concrete mix without overspending cement.

By agreement between the manufacturer (quarry) and the consumer, during a feasibility study, it is allowed to supply sand for concrete with a particle size modulus of up to 3.5, as well as with a total residue on sieve No. 063 up to 75%.

As materials for pavement installation, natural and enriched sands, sands from crushing screenings and enriched from crushing screenings of increased size, large, medium and fine, should be supplied and used in accordance with the requirements of regulatory and technical documents.

Sands that meet the requirements of clause 1.6.7 must be supplied and used as aggregates for mortars:

medium, fine and very fine natural sands;

medium and fine enriched sands.

in natural sands and from crushing screenings of increased size, large and medium. . . , . . .10

the same, in small and very small ....... 15

in enriched sand of increased size, coarse

and average............5

the same, in small ............10

in enriched sand from crushing screenings.... 5

By agreement of the enterprise (quarry)-manufacturer with the consumer in medium, fine and very fine sands intended for mortars and road construction works, as well as in sand from crushing screenings intended for road construction works, the content of grains passing through the sieve with grid No. 016, up to 20% by weight is allowed.

GOST 8736-85 Page 5

1.6.6. The presence of grains larger than 5 mm should not exceed % by weight:

in natural sand. . . . -.......10

in sand from crushing screenings ........ 15

in enriched sand and enriched sand from screenings of crushing ............... 5

1.6.7. For the manufacture of building mortars (except for plaster mortars for the finishing layer), medium natural and medium enriched sands with a particle size modulus not exceeding 2.2, as well as fine natural and fine enriched sands, must be supplied and used. The content of grains larger than 5 mm in mortar sands should not exceed 0.5% by weight.

Very fine sand must be supplied and used for the preparation of plaster mortars for the finishing layer. The content of grains larger than 1.25 mm in sands used in plaster solutions for the finishing layer should not exceed 0.5% by weight.

By agreement of the enterprise (quarry)-manufacturer with the consumer, it is allowed to supply and use for mortars (except for plaster mortars for the finishing layer) medium natural sand and medium enriched sand, in which the content of grains larger than 5 mm does not exceed 5% by weight. For the manufacture of plaster mortar for the finishing layer, it is allowed to supply and use very fine natural sand, in which the content of grains larger than 1.25 mm does not exceed 5% by weight.

1.7. The number of dust-like and clay particles in the sand should not exceed the values ​​\u200b\u200bspecified in Table. 2.

table 2

In sand from crushing screenings, intended for road construction, and in natural very fine sand, intended for use in plaster solutions for the finishing layer, the content of dust and clay particles up to 7% by weight is allowed.

Sand of all types should not contain foreign clogging impurities.

1.8. Sand intended for concretes and mortars, when treated with a solution of sodium hydroxide (colorimetric test for organic impurities according to GOST 8735-75), should not give the solution a color that matches or is darker than the color of the standard. The use of sand that does not meet this requirement is allowed only after special tests and a feasibility study.

1.9. Igneous, metamorphic or dense sedimentary rocks, as well as gravel, should be used to produce sand from crushing screenings and enriched sand from crushing screenings.

Depending on the strength of the original rock and gravel, sands are divided into four grades: 1000, 800, 600 and 400.

The strength of the original rock and gravel must correspond to that indicated in Table. 3.

Table 3

Igneous and metamorphic rocks used for the production of sand from crushing screenings must have a compressive strength of at least 60 MPa (600 kgf / cm 2), and sedimentary rocks - at least 40 MPa (400 kgf / cm 2).

By agreement between the manufacturer and the consumer, it is allowed to release sand obtained from screenings of crushing sedimentary rocks having a compressive strength below 40 MPa (400 kgf / cm 2), but not less than 20 MPa (200 kgf / cm 2).

1.10. Rocks and gravel used to obtain sand from crushing screenings should not contain weak differences in an amount of more than 10% by weight, and rocks with a compressive strength below 40 MPa

GOST 8736-85 Page 7

(400 kgf / cm 2), and gravel brand Dr24 - no more than 15% by weight.

With a higher content of weak differences, it is allowed to use only screenings obtained after the second and subsequent stages of crushing.

Rocks with a compressive strength in a water-saturated state of less than 20 MPa (200 kgf / cm 2) are considered weak.

1.11. The quality of the mixture of natural sand and sand from crushing screenings must meet the requirements of this standard for the quality of sands from crushing screenings.

1.12. Sand from associated rocks and waste from mining and processing enterprises, having an average grain density of more than 2800 kg / m 3 or containing grains of rocks and minerals classified according to GOST 23845-79 and GOST 24100-80 to harmful impurities, must be produced according to industry and republican standards or technical specifications. At the same time, for each deposit or group of deposits, restrictions should be provided for the maximum value of the average density and the content of rocks and minerals classified as harmful impurities in accordance with GOST 23845-79 and GOST 24100-80, as well as methods for determining the content of rocks and minerals classified as harmful impurities.

Limitations on the average density and content of rocks and minerals classified as harmful impurities are established on the basis of special studies, depending on the purpose of the sand and the operating conditions of the structures in which it is used.

2. ACCEPTANCE RULES

2.1. Sand produced by the manufacturer (quarry) must be accepted technical control this enterprise. The manufacturer (quarry) must guarantee that the sand meets the requirements of this standard.

2.2. Sand is supplied in batches. The amount of sand shipped to one consumer at the same time in one train or in one vessel is considered a batch.

On shipment by car the batch is the amount of sand shipped to one consumer during the day.

2.3. The amount of sand supplied is determined by volume or mass. Sand measurement is carried out in wagons, ships and cars.

Weighing of sand shipped in wagons or cars is carried out on railway or truck scales. / The mass of sand shipped in ships is determined by the ship's draft.

Page 8 GOST 8736-85

2.4. The recalculation of the amount of sand from weight units to volume units is carried out according to the values ​​of the bulk density of sand, determined in the state of natural moisture.

In wet technological processes of sand production, the moisture content of the supplied sand and the bulk density used to convert the amount of sand from weight units to volume units are set by agreement between the manufacturer (quarry) and the consumer, taking into account sand2 mining conditions, quarry operating experience, geological exploration data, time year, as well as the compaction coefficients of sand when it is loaded into vehicles.

2.5. Acceptance control of the quality of sand at the enterprise (quarry)-manufacturer consists of determining the grain composition, the content of dust and clay particles, including clay. lumps. Sand quality control according to the indicated indicators is carried out daily by one replacement sample according to GOST 8735-75.

The determination of the bulk density of sand is carried out once a quarter.

For sand obtained from associated rocks and waste from mining and processing enterprises, in addition, the average density of grains and the content of inclusions of rocks and minerals classified as harmful impurities are determined. These indicators determine in each case changes in the properties of sand, but at least once a year.

For the specified sand supplied in accordance with clause 1.12, the frequency of determining the average density and content of rocks and minerals classified as harmful impurities is established by industry, republican standards or

specifications, but these determinations must be made at least once a quarter.

2.6. The security of the values ​​​​of the sand fineness module established by the standard, indicated in Table. 1 for each group of sand, during acceptance control according to paragraphs. 2.6-2.8 must be at least 95% for enriched sand of all types of the highest quality category, at least 90% for enriched sand of all types of the first quality category and at least 80% for natural sands and from screenings of crushing.

It is allowed, upon agreement between the manufacturer and the consumer, the supply of sand, the values ​​of the particle size modulus of which are within the standard values ​​indicated in Table. 1 for two adjacent groups of sand, if the difference between the upper and lower limits of the fineness modulus does not exceed 0.5. At the same time, the above-mentioned various kinds sand requirements for the security of fineness modulus values ​​within