Norms of water consumption for protection and fire extinguishing of oil and gas industry facilities. Calculation of a water supply system with a variable flow rate (irrigation rings)

It has been discussed many times, you say? And, like, is everything clear? What are your thoughts on this little study:
The main contradiction that has not been resolved by the norms today is between the circular sprinkler irrigation map (epures) and the square (in the vast majority) arrangement of sprinklers on the protected (calculated according to SP5) area.
1. For example, we need to ensure the extinguishing of a certain room with an area of ​​​​120 m2 with an intensity of 0.21 l / s * m2. From the SVN-15 sprinkler with k = 0.77 (Biysk) at a pressure of three atmospheres (0.3 MPa), q = 10 * 0.77 * SQRT (0.3) = 4.22 l / s will flow , while on the passport area of ​​12 m2 the intensity will be provided (according to the passport for the sprinkler) i = 0.215 l/s*m2. Since the passport contains a reference to the fact that this sprinkler complies with the requirements of GOST R 51043-2002, then, according to clause 8.23 ​​(checking the intensity and protected area), we must consider these 12m2 (according to the passport - the protected area) as the area of ​​a circle with radius R = 1.95 m. By the way, 0.215 * 12 = 2.58 (l / s) will pour out onto such an area, which is only 2.58 / 4.22 = 0.61 of the total sprinkler flow, i.e. almost 40% of the supplied water flows outside the normative protected area.
SP5 (Tables 5.1 and 5.2) requires that the normative intensity be ensured in the normalized protected area (and there, as a rule, sprinklers in the amount of at least 10 pieces are arranged in a square-nested way), while according to clause B.3.2 of SP5:
- conditional calculated area protected by one sprinkler: Ω = L2, here L is the distance between the sprinklers (i.e. the side of the square, at the corners of which there are sprinklers).
And, understanding intellectually that all the water pouring out of the sprinkler will remain in the protected area, when we have sprinklers at the corners of conditional squares, we very simply consider the intensity that the AFS provides on the standard protected area: the entire flow (and not 61%) through dictating sprinkler (through the rest, the flow rate will be higher by definition) is divided by the area of ​​a square with a side equal to the spacing of the sprinklers. Absolutely the same as our foreign colleagues believe (in particular, for ESFR), i.e., in reality, according to 4 sprinklers placed at the corners of a square with a side of 3.46 m (S = 12 m2).
In this case, the calculated intensity on the normative protected area will be 4.22/12 = 0.35 l / s * m2 - all the water will pour out onto the fire!
Those. to protect the area, we can reduce the flow rate by 0.35 / 0.215 = 1.63 times (ultimately - construction costs), and obtain the intensity required by the norms, but we do not need 0.35 l / s * m2, 0.215 is enough l/s*m2. And for the entire standard area of ​​120 m2, we need (simplified) calculated 0.215 (l / s * m2) * 120 (m2) \u003d 25.8 (l / s).
But here, ahead of the rest of the planet, comes out developed and introduced in 1994. Technical Committee TK 274 "Fire Safety" GOST R 50680-94, namely this item:
7.21 Irrigation intensity is determined in a selected area during the operation of one sprinkler for sprinkler ... sprinklers at design pressure. - (at the same time, the sprinkler irrigation map with the intensity measurement method adopted in this GOST is a circle).
This is where we sailed, because, literally understanding clause 7.21 of GOST R 50680-94 (extinguishing with one piece) in conjunction with clause B.3.2 of SP5 (protecting the area), we must ensure the standard intensity on the area of ​​the square inscribed in a circle with an area of ​​12 m2, because in the passport for the sprinkler, this (round!) Protected area is given, and beyond the boundaries of this circle, the intensity will be already less.
The side of such a square (sprinkler spacing) is 2.75 m, and its area is no longer 12 m2, but 7.6 m2. At the same time, when extinguishing on the standard area (when several sprinklers are operating), the actual irrigation intensity will be 4.22 / 7.6 = 0.56 (l / s * m2). And in this case, we will need 0.56 (l / s * m2) * 120 (m2) \u003d 67.2 (l / s) for the entire regulatory area. This is 67.2 (l / s) / 25.8 (l / s) = 2.6 times more than when calculating for 4 sprinklers (square)! And how much does this increase the cost of pipes, pumps, tanks, etc.?

Rationing of water consumption for extinguishing fires in high-rise rack warehouses. UDC 614.844.2
L. Meshman, V. Bylinkin, R. Gubin, E. Romanova

Rationing of water consumption for extinguishing fires in high-rise rack warehouses. UDC B14.844.22

L. Meshman

V. Bylinkin

Candidate of Technical Sciences, Leading Researcher,

R. Gubin

Senior Researcher,

E. Romanova

Researcher

At present, the main initial characteristics, according to which the calculation of water consumption for automatic fire extinguishing installations (AFS) is carried out, are the normative values ​​of irrigation intensity or pressure at the dictating sprinkler. Irrigation intensity is used in regulatory documents regardless of the design of sprinklers, and pressure is applied only to a specific type of sprinkler.

Irrigation intensity values ​​are given in SP 5.13130 ​​for all groups of premises, including storage buildings. This implies the use of sprinkler AFS under the roof of the building.

However, the accepted values ​​of irrigation intensity depending on the group of premises, storage height and type of fire extinguishing agent, given in Table 5.2 of SP 5.13130, defy logic. For example, for room group 5, with an increase in the storage height from 1 to 4 m (for each meter of height) and from 4 to 5.5 m, the intensity of irrigation with water increases proportionally by 0.08 l / (s-m2).

It would seem that a similar approach to rationing the supply of a fire extinguishing agent for extinguishing a fire should be extended to other groups of premises and to extinguish a fire with a foam concentrate solution, but this is not observed.

For example, for room group 5, when using a foaming agent solution at a storage height of up to 4 m, the irrigation intensity increases by 0.04 l / (s-m2) for every 1 m of rack storage height, and at a storage height of 4 to 5.5 m, the intensity irrigation increases 4 times, i.e. by 0.16 l / (s-m2), and is 0.32 l / (s-m2).

For room group 6, the increase in the intensity of irrigation with water is 0.16 l / (s-m2) up to 2 m, from 2 to 3 m - only 0.08 l / (s-m2), more than 2 to 4 m - intensity does not change, and at a storage height of more than 4-5.5 m, the irrigation intensity changes by 0.1 l/(s-m2) and amounts to 0.50 l/(s-m2). At the same time, when using a foaming agent solution, the irrigation intensity is up to 1 m - 0.08 l / (s-m2), over 1-2 m it changes by 0.12 l / (s-m2), over 2-3 m - by 0.04 l / (s-m2), and then over 3 to 4 m and from over 4 to 5.5 m - by 0.08 l / (s-m2) and is 0.40 l / (s- m2).

In rack warehouses, goods are most often stored in boxes. In this case, when extinguishing a fire, the jets of extinguishing agent do not, as a rule, directly affect the combustion zone (the exception is a fire on the uppermost tier). Part of the water dispersed from the sprinkler spreads over the horizontal surface of the boxes and flows down, the rest, which does not fall on the boxes, forms a vertical protective curtain. Partially oblique jets fall into the free space inside the rack and wet the goods that are not packed in boxes, or the side surface of the boxes. Therefore, if for open surfaces the dependence of irrigation intensity on the type of fire load and its specific load is beyond doubt, then when extinguishing rack warehouses, this dependence does not manifest itself so noticeably.

Nevertheless, if we allow some proportionality in the increment of irrigation intensity depending on the storage height and the height of the room, then the irrigation intensity becomes possible to determine not through discrete values ​​​​of the storage height and the height of the room, as presented in SP 5.13130, but through a continuous function expressed equation

where 1dict is the intensity of irrigation by the dictating sprinkler depending on the height of storage and the height of the room, l/(s-m2);

i55 - intensity of irrigation by a dictating sprinkler at a storage height of 5.5 m and a room height of not more than 10 m (according to SP 5.13130), l/(s-m2);

F - coefficient of variation of storage height, l/(s-m3); h - storage height of the fire load, m; l - coefficient of variation of the height of the room.

For room groups 5, the irrigation intensity i5 5 is 0.4 l/(s-m2), and for room groups b - 0.5 l/(s-m2).

The storage height variation factor φ for room groups 5 is assumed to be 20% less than for room groups b (by analogy with SP 5.13130).

The value of the coefficient of variation of the height of the room l is given in table 2.

When performing hydraulic calculations of the AFS distribution network, it is necessary to determine the pressure at the dictating sprinkler based on the calculated or standard irrigation intensity (according to SP 5.13130). The pressure at the sprinkler, corresponding to the desired intensity of irrigation, can only be determined by the family of irrigation diagrams. But manufacturers of sprinklers, as a rule, do not provide irrigation plots.

Therefore, designers experience inconvenience when deciding on the design value of pressure at the dictating sprinkler. In addition, it is not clear what height to take as the calculated one for determining the intensity of irrigation: the distance between the sprinkler and the floor or between the sprinkler and the upper level of the fire load. It is also unclear how to determine the intensity of irrigation: on the area of ​​a circle with a diameter equal to the distance between the sprinklers, or on the entire area irrigated by the sprinkler, or taking into account the mutual irrigation by adjacent sprinklers.

For fire protection of high-rise rack warehouses, sprinkler automatic fire extinguishers are now being widely used, the sprinklers of which are placed under the warehouse cover. This technical solution requires a large amount of water. For these purposes, special sprinklers are used, both domestically produced, for example, SOBR-17, SOBR-25, and foreign, for example, ESFR-17, ESFR-25, VK503, VK510 with an outlet diameter of 17 or 25 mm.

In service stations for SOBR sprinklers, in brochures for ESFR sprinklers from Tyco and Viking, the main parameter is the pressure at the sprinkler, depending on its type (SOBR-17, SOBR-25, ESFR-17, ESFR-25, VK503, VK510, etc.). etc.), on the type of goods stored, the height of storage and the height of the room. This approach is convenient for designers, because eliminates the need to search for information on irrigation intensity.

At the same time, is it possible, regardless of the specific design of the sprinkler, to use some generalized parameter to assess the possibility of using any designs of sprinklers developed in the future? It turns out that it is possible if we use the pressure or flow rate of the dictating sprinkler as a key parameter, and as an additional parameter, the irrigation intensity on a given area at a standard sprinkler installation height and standard pressure (according to GOST R 51043). For example, you can use the value of irrigation intensity obtained without fail during certification tests of special-purpose sprinklers: the area on which the irrigation intensity is determined is 12 m2 for general-purpose sprinklers (diameter ~ 4 m), for special sprinklers - 9.6 m2 ( diameter ~ 3.5 m), sprinkler installation height 2.5 m, pressure 0.1 and 0.3 MPa. Moreover, information about the irrigation intensity of each type of sprinkler, obtained in the course of certification tests, must be indicated in the passport for each type of sprinkler. With the specified initial parameters for high-rise rack warehouses, the irrigation intensity should not be less than that given in Table 3.

The true intensity of AFS irrigation during the interaction of adjacent sprinklers, depending on their type and the distance between them, can exceed the intensity of irrigation of the dictating sprinkler by 1.5-2.0 times.

With regard to high-rise warehouses (with a storage height of more than 5.5 m), two initial conditions can be taken to calculate the normative value of the dictating sprinkler flow:

1. With a storage height of 5.5 m and a room height of 6.5 m.

2. With a storage height of 12.2 m and a room height of 13.7 m. The first fixed point (minimum) is set on the basis of the data of SP 5.131301 on the intensity of irrigation and the total consumption of water AFS. For room group b, the irrigation intensity is at least 0.5 l/(s-m2) and the total flow rate is at least 90 l/s. The consumption of a general-purpose dictating sprinkler according to the norms of SP 5.13130 ​​with such irrigation intensity is at least 6.5 l / s.

The second reference point (maximum) is set on the basis of the data given in the technical documentation for SOBR and ESFR sprinklers.

With approximately equal flow rates of sprinklers SOBR-17, ESFR-17, VK503 and SOBR-25, ESFR-25, VK510 for identical characteristics of the warehouse, SOBR-17, ESFR-17, VK503 require higher pressure. According to all types of ESFR (except ESFR-25), with a storage height of more than 10.7 m and a room height of more than 12.2 m, an additional level of sprinklers inside the racks is required, which requires additional consumption of fire extinguishing agent. Therefore, it is advisable to focus on the hydraulic parameters of sprinklers SOBR-25, ESFR-25, VK510.

For groups of premises 5 and b (according to SP 5.13130) of high-rise rack warehouses, the equation for calculating the flow rate of the dictating sprinkler of water AFS is proposed to be calculated by the formula

Table 1

table 2

Table 3

With a storage height of 12.2 m and a room height of 13.7 m, the pressure at the ESFR-25 dictating sprinkler must be at least: according to NFPA-13 0.28 MPa, according to FM 8-9 and FM 2-2 0.34 MPa. Therefore, the flow rate of the dictating sprinkler for the group of rooms 6 is taken taking into account the pressure according to FM, i.e. 0.34 MPa:

where qЕSFR - ESFR-25 sprinkler flow rate, l/s;

KRF - productivity factor in the dimension according to GOST R 51043, l / (s-m water column 0.5);

KISO - performance factor in terms of ISO 6182-7, l/(min-bar0.5); p - pressure at the sprinkler, MPa.

The flow rate of the dictating sprinkler for a group of rooms 5 is taken in the same way according to formula (2), taking into account the pressure according to NFPA, i.e. 0.28 MPa - flow rate = 10 l/s.

For room groups 5, the flow rate of the dictating sprinkler is taken to be q55 = 5.3 l/s, and for room groups 6 - q55 = 6.5 l/s.

The value of the coefficient of variation of the storage height is given in table 4.

The value of the room height variation coefficient b is given in Table 5.

The ratios of the pressures given in , with the flow rate calculated at these pressures for the ESFR-25 and SOBR-25 sprinklers, are presented in Table 6. The flow rate for groups 5 and 6 was calculated using formula (3).

As follows from Table 7, the flow rates of the dictating sprinkler for groups of rooms 5 and 6, calculated by formula (3), correspond quite well with the flow rate of ESFR-25 sprinklers, calculated by formula (2).

With quite satisfactory accuracy, it is possible to take the difference in flow between groups of rooms 6 and 5 equal to ~ (1.1-1.2) l / s.

Thus, the initial parameters of regulatory documents for determining the total consumption of AFS in relation to high-rise rack warehouses, in which sprinklers are placed under the cover, can be:

■ irrigation intensity;

■ pressure at the dictating sprinkler;

■ consumption of the dictating sprinkler.

The most acceptable, in our opinion, is the flow rate of the dictating sprinkler, which is convenient for designers and does not depend on the specific type of sprinkler.

The use of “dictating sprinkler flow rate” as the dominant parameter should also be introduced into all regulatory documents in which irrigation intensity is used as the main hydraulic parameter.

Table 4

Table 5

Table 6

Storage height/room height	Options			SOBR-25	Estimated flow rate, l / s, according to the formula (3)
					group 5	group 6
	Pressure, MPa
	Consumption, l / s
	Pressure, MPa
	Consumption, l / s
	Pressure, MPa
	Consumption, l / s
	Pressure, MPa
	Consumption, l / s
	Pressure, MPa
	Consumption, l / s
	Consumption, l / s

LITERATURE:

1. SP 5.13130.2009 “Fire protection systems. Fire alarm and fire extinguishing installations are automatic. Norms and rules of design».

2. STO 7.3-02-2009. Standard of the organization for the design of automatic water fire extinguishing installations using SOBR sprinklers in high-rise warehouses. General technical requirements. Biysk, ZAO PO Spetsavtomatika, 2009.

3. Model ESFR-25. Early Suppression Fast Response Pendent Sprinklers 25 K-factor/Fire & Building Products - TFP 312 / Tyco, 2004 - 8 p.

4. ESFR Pendent Shrinkler VK510 (K25.2). Viking/ Technical Data, Form F100102, 2007 - 6 p.

5. GOST R 51043-2002 “Automatic water and foam fire extinguishing installations. Sprinklers. General technical requirements. Test Methods".

6. NFPA 13. Standard for the Installation of Sprinkler Systems.

7.FM 2-2. FM Global. Installation Rules for Suppression Mode Automatic Sprinklers.

8. FM Loss Prevention Data 8-9 Provides alternative fire protection methods.

9. Meshman L.M., Tsarichenko S.G., Bylinkin V.A., Aleshin V.V., Gubin R.Yu. Sprinklers for water and foam automatic fire extinguishing installations. Teaching aid. M.: VNIIPO, 2002, 314 p.

10. ISO 6182-7 Requiutments and Test Methods for Earle Suppression fast Response (ESFR) Sprinklers.

FEDERAL STATE BUDGET EDUCATIONAL INSTITUTION OF HIGHER PROFESSIONAL EDUCATION

"CHUVASH STATE PEDAGOGICAL UNIVERSITY

them. AND I. YAKOVLEV"

Department of Fire Safety

Lab #1

discipline: "Fire extinguishing automation"

on the topic: "Determining the intensity of irrigation of water fire extinguishing installations."

Completed by: student of the 5th year of the PB-5 group, specialty fire safety

Faculty of Physics and Mathematics

Checked by: Sintsov S.I.

Cheboksary 2013

Determination of the intensity of irrigation of water fire extinguishing installations

1. The purpose of the work: to teach students the methodology for determining the specified intensity of irrigation with water from sprinklers of a water fire extinguishing installation.

2. Brief theoretical information

The intensity of irrigation with water is one of the most important indicators characterizing the effectiveness of a water fire extinguishing installation.

According to GOST R 50680-94 “Automatic fire extinguishing installations. General technical requirements. Test Methods". Tests should be carried out before putting the installations into operation and during operation at least once every five years. There are the following ways to determine the intensity of irrigation.

1. According to GOST R 50680-94, irrigation intensity is determined at the selected site of the installation when one sprinkler for sprinklers and four sprinklers for deluge plants are operating at design pressure. The choice of sites for testing sprinkler and deluge installations is carried out by representatives of the customer and the State Fire Supervision Service on the basis of approved regulatory documentation.

Under the installation site selected for testing, metal pallets with a size of 0.5 * 0.5 m and a side height of at least 0.2 m should be installed at control points. The number of control points should be taken at least three, which should be located in the most places unfavorable for irrigation. Irrigation intensity I l / (s * m 2) at each control point is determined by the formula:

where W under - the volume of water collected in the sump during the operation of the installation in steady state, l; τ is the duration of the installation, s; F is the area of ​​the pallet, equal to 0.25 m 2.

Irrigation intensity at each control point should not be lower than the standard (Tables 1-3 NPB 88-2001*).

This method requires spillage of water over the entire area of ​​the design areas and in the conditions of an operating enterprise.

2. Determining the intensity of irrigation using a measuring container. Using the design data (normative irrigation intensity; actual area occupied by the sprinkler; diameters and lengths of pipelines), a design scheme is drawn up and the required pressure at the tested sprinkler and the corresponding pressure in the supply pipeline at the control unit are calculated. Then the sprinkler is changed to deluge. A measuring container is installed under the sprinkler, connected by a hose to the sprinkler. The valve opens in front of the valve of the control unit and, using the pressure gauge showing the pressure in the supply pipeline, the pressure obtained by calculation is established. In the steady state of the expiration, the flow rate from the sprinkler is measured. These operations are repeated for each subsequent tested sprinkler. Irrigation intensity I l / (s * m 2) at each control point is determined by the formula and should not be lower than the standard:

where W under is the volume of water in the measuring tank, l, measured over time τ, s; F is the area protected by the sprinkler (according to the project), m 2.

When unsatisfactory results are obtained (at least one of the sprinklers), the causes must be identified and eliminated, and then the tests are repeated.

Choice of extinguishing agent, method of fire extinguishing and type of automatic fire extinguishing installation.

Possible OTVs are selected in accordance with NPB 88-2001. Taking into account the information on the applicability of fire extinguishing agents for automatic fire extinguishers, depending on the class of fire and the properties of the material assets located, it agrees with the recommendations for extinguishing fires of class A1 (A1 - burning of solids accompanied by smoldering), finely sprayed water is suitable for TRV.

In the calculated graphic task, we accept AUP-TRV. In the residential building under consideration, it will be a water-filled stringer (for rooms with a minimum air temperature of 10 ° C and above). Sprinkler installations are accepted in rooms with increased fire hazard. The design of expansion valve installations should be carried out taking into account the architectural and planning solutions of the protected premises and the technical parameters, technical installations of expansion valve given to the documentation for sprayers or modular expansion valve installations. The parameters of the designed sprinkler AFS (irrigation intensity, OTV consumption, the minimum irrigation area, the duration of water supply and the maximum distance between the sprinklers, are determined in accordance. In section 2.1, there was a certain group of premises in the RGZ. To protect the premises, B3 sprinklers - “Maxtop” should be used.

Table 3

Fire extinguishing installation parameters.

2.3. Tracing of fire extinguishing systems.

The figure shows the routing scheme, according to which it is necessary to install a sprinkler in the protected room:

Picture 1.

The number of sprinklers in one section of the installation is not limited. At the same time, in order to issue a signal specifying the location of a building fire, as well as to turn on warning and smoke exhaust systems, it is recommended to install liquid flow detectors with a response pattern on the supply pipelines. For group 4, the minimum distance from the top edge of objects to sprinklers should be 0.5 meters. The distance from the outlet of the sprinkler sprinkler installed vertically to the floor plane should be from 8 to 40 cm. In the designed AFS, this distance is assumed to be 0.2 m. Within one protected element, single sprinklers with the same diameter should be installed, the type of sprinkler will be determined by the result of the hydraulic calculation.

3. Hydraulic calculation of the fire extinguishing system.

The hydraulic calculation of the sprinkler network is performed in order to:

1. Determination of water flow

2. Comparison of the specific consumption of irrigation intensity with the regulatory requirement.

3. Determination of the required pressure of water feeders and the most economical pipe diameters.

The hydraulic calculation of a fire-fighting water supply system is reduced to solving three main tasks:

1. Determination of the pressure at the inlet to the fire water supply (on the axis of the outlet pipe, pump). If the estimated water flow is set, the pipeline routing scheme, their length and diameter, as well as the type of fittings. In this case, the calculation begins with the determination of pressure losses during the movement of water, depending on the diameter of the pipelines, etc. The calculation ends with the choice of the brand of the pump according to the estimated water flow and pressure at the beginning of the installation

2. Determination of water flow at a given pressure at the beginning of the fire pipeline. The calculation begins with the determination of the hydraulic resistance of all elements of the pipeline and ends with the establishment of water flow from a given pressure at the beginning of the fire water pipeline.

3. Determining the diameter of the pipeline and other elements according to the estimated water flow and pressure at the beginning of the pipeline.

Determination of the required pressure at a given intensity of irrigation.

Table 4

Parameters of sprinklers "Maxtop"

In the section, a sprinkler AFS was adopted, respectively, we assume that sprinklers of the SIS-PN 0 0.085 brand will be used - sprinkler, water, special-purpose sprinklers with a concentric flow, installed vertically without a decorative coating with a performance factor of 0.085, a nominal response temperature of 57 °, design flow water in the dictating sprinkler is determined by the formula:

The productivity factor is 0.085;

The required free head is 100 m.

3.2. Hydraulic calculation of dividing and supply pipelines.

For each fire extinguishing section, the most remote or the most highly located protected zone is determined, and the hydraulic calculation is carried out for this zone within the calculated area. In accordance with the type of tracing of the fire extinguishing system, it is a dead end in configuration, not symmetrical with the morning water pipe, it is not combined. The free head at the dictating sprinkler is 100 m, the head loss in the supply section is equal to:

Plot length of pipeline section between sprinklers;

Fluid flow in the pipeline section;

The coefficient characterizing the pressure loss along the length of the pipeline for the selected grade is 0.085;

The required free head for each subsequent sprinkler is the sum consisting of the required free head for the previous sprinkler and the pressure loss in the pipeline section between them:

The water consumption of the foaming agent from the subsequent sprinkler is determined by the formula:

In paragraph 3.1, the flow rate of the dictating sprinkler was determined. Pipelines of water-filled installations must be made of galvanized and stainless steel, the diameter of the pipeline is determined by the formula:

Plot water consumption, m 3 / s

The speed of water movement m / s. we accept the speed of movement from 3 to 10 m / s

We express the diameter of the pipeline in ml and increase it to the nearest value (7). Pipes will be connected by welding, fittings are made on site. Pipeline diameters should be determined at each design section.

The results of the hydraulic calculation are summarized in Table 5.

Table 5

3.3 Determination of the required pressure in the system

The total number of different requirements for the production and control of a sprinkler is quite large, so we will only consider the most important parameters.

1. Quality indicators

1.1 Tightness

This is one of the main indicators that the user of a sprinkler system faces. Indeed, a poorly sealed sprinkler can cause a lot of trouble. No one will like it if people, expensive equipment or goods suddenly start to drip water. And if the loss of tightness occurs due to the spontaneous destruction of a heat-sensitive locking device, the damage from spilled water can increase several times.

The design and production technology of modern sprinklers, which have been improved over the years, allow you to be sure of their reliability.

The main element of the sprinkler, which ensures the tightness of the sprinkler in the most difficult operating conditions, is a Belleville spring. (5) . The importance of this element cannot be overestimated. The spring allows you to compensate for minor changes in the linear dimensions of the sprinkler parts. The fact is that in order to ensure reliable tightness of the sprinkler, the elements of the locking device must constantly be under a sufficiently high pressure, which is provided during assembly with a locking screw. (1) . Over time, this pressure can cause a slight deformation of the sprinkler body, which, however, would be sufficient to break the tightness.

There was a time when some of the manufacturers of sprinklers used rubber gaskets as a sealing material to reduce the cost of construction. Indeed, the elastic properties of rubber also make it possible to compensate for minor linear dimensional changes and provide the required tightness.

Figure 2. Sprinkler with rubber gasket.

However, this did not take into account that, over time, the elastic properties of rubber deteriorate, and loss of tightness may occur. But the worst thing is that rubber can stick to the surfaces to be sealed. Therefore, when fire, after the destruction of the temperature-sensitive element, the sprinkler cover remains tightly glued to the body and water does not flow from the sprinkler.

Such cases were recorded during a fire at many facilities in the United States. After that, manufacturers carried out a large-scale action to recall and replace all sprinklers with rubber sealing rings 3 . In the Russian Federation, the use of sprinklers with a rubber seal is prohibited. At the same time, as is known, supplies of cheap sprinklers of this design continue to some of the CIS countries.

In the production of sprinklers, both domestic and foreign standards provide for a number of tests that make it possible to guarantee tightness.

Each sprinkler is tested by hydraulic (1.5 MPa) and pneumatic (0.6 MPa) pressure, and it is also tested for resistance to hydraulic shock, that is, pressure surges up to 2.5 MPa.

Vibration testing provides confidence that fills will perform reliably under the harshest operating conditions.

1.2 Strength

Of no small importance for maintaining all the technical characteristics of any product is its strength, that is, resistance to various external influences.

The chemical strength of the sprinkler structural elements is determined by tests for resistance to the effects of a foggy environment from salt spray, an aqueous solution of ammonia and sulfur dioxide.

The impact resistance of the sprinkler must ensure the integrity of all its elements when falling onto a concrete floor from a height of 1 meter.

The sprinkler outlet must withstand the impact water coming out of it under a pressure of 1.25 MPa.

In case of fast fire development sprinklers in air or start-controlled systems may be exposed to high temperatures for some time. In order to be sure that the fill does not deform and, therefore, does not change its characteristics, heat resistance tests are carried out. At the same time, the body of the sprinkler must withstand a temperature of 800°C for 15 minutes.

To test the resistance to climatic influences, sprinklers are tested for negative temperatures. The ISO standard provides for testing sprinklers at -10°С, the requirements of GOST R are somewhat stricter and are determined by the climate: it is necessary to conduct long-term tests at -50°С and short-term tests at -60°С.

1.3 Reliability of the thermal lock

One of the most critical elements of a sprinkler sprinkler is the thermal lock of the sprinkler. The technical characteristics and quality of this element largely determine the successful operation of the sprinkler. Timeliness depends on the accurate operation of this device, in accordance with the declared technical characteristics. extinguishing a fire and the absence of false positives in standby mode. Over the long history of the existence of a sprinkler sprinkler, many types of thermal lock designs have been proposed.




Figure 3 Sprinklers with a glass flask and a fusible element.

Fusible thermal locks with a Wood's alloy-based thermosensitive element, which softens at a given temperature and the lock disintegrates, as well as thermal locks that use a glass thermosensitive flask, have passed the test of time. Under the action of heat, the liquid in the flask expands, exerting pressure on the walls of the flask, and when a critical value is reached, the flask collapses. Figure 3 shows ESFR type fills with different types of thermal locks.

To check the reliability of the thermal lock in standby mode and in the event of a fire, a number of tests are provided.

The nominal operating temperature of the lock must be within tolerance. For sprinklers in the lower temperature range, the response temperature deviation should not exceed 3°C.

The thermal lock must be resistant to thermal shock (a sharp temperature rise of 10°C below the nominal response temperature).

The heat resistance of the thermal lock is checked by gradually heating the temperature to 5°C below the nominal response temperature.

If a glass flask is used as a thermal lock, then it is necessary to check its integrity using a vacuum.

Both the glass bulb and the fusible element are subject to strength testing. So, for example, a glass bulb must withstand a load six times greater than its load in operating mode. The fusible element is set to fifteen times the limit.

2. Purpose indicators

2.1 Thermal sensitivity of the lock

According to GOST R 51043, the sprinkler response time is subject to verification. It should not exceed 300 seconds for low temperature sprinklers (57 and 68°C) and 600 seconds for the highest temperature sprinklers.

A similar parameter is absent in the foreign standard, instead RTI (response time index) is widely used: a parameter characterizing the sensitivity of a temperature-sensitive element (glass bulb or fusible lock). The lower its value, the more sensitive to heat this element. Together with another parameter - C (conductivity factor - measure thermal conductivity between the temperature sensing element and the sprinkler structural elements) they form one of the most important characteristics of the sprinkler - the response time.




Figure 4 Zone boundaries that determine sprinkler response.

Figure 4 shows areas that characterize:

1 – standard response time sprinkler; 2 – special response time sprinkler; 3 - quick response time sprinkler.

For sprinklers with different response times, rules have been established for their use to protect facilities with different levels of fire hazard:

• depending on the size;
• depending on the type;
• fire load storage parameters.

It should be noted that Appendix A (recommended) of GOST R 51043 contains a methodology for determining Thermal inertia coefficient and Heat loss coefficient due to thermal conductivity based on ISO/FDIS6182-1 methodologies. However, there has been no practical use of this information so far. The fact is that, although paragraph A.1.2 states that these factors should be used "... to determine the response time of sprinklers in a fire, justify the requirements for their placement in the premises”, there are no real methods for their use. Therefore, these parameters cannot be found among the technical characteristics of sprinklers.

In addition, an attempt to determine the coefficient of thermal inertia by the formula from Annexes A GOST R 51043:

The fact is that an error was made when copying the formula from the ISO / FDIS6182-1 standard.

A person who has knowledge of mathematics within the framework of the school curriculum will easily notice that when converting the type of formula from a foreign standard (it is not clear why this was done, maybe to make it look less like plagiarism?), the minus sign was omitted in the degree of the factor ν to 0 ,5, which is in the numerator of the fraction.

At the same time, it is necessary to note the positive aspects in modern rule-making. Until recently, the sensitivity of a sprinkler can be safely attributed to quality parameters. The now newly developed (but not yet effective) SP 6 4 already contains instructions for the use of sprinklers that are more sensitive to temperature changes to protect the most fire hazardous premises:

5.2.19 When fire load not less than 1400 MJ / m 2 for warehouses, for rooms with a height of more than 10 m and for rooms in which the main combustible product is LVZH and GJ, the coefficient of thermal inertia of sprinklers should be less than 80 (m·s) 0.5.

Unfortunately, it is not entirely clear, whether intentionally or due to inaccuracy, the requirement for the temperature sensitivity of the sprinkler is set only on the basis of the thermal inertia coefficient of the temperature sensing element, without taking into account the coefficient of heat loss due to thermal conductivity. And this is at a time when, according to the international standard (Fig. 4), sprinklers with a heat loss coefficient due to thermal conductivity more than 1.0 (m / s) 0.5 are no longer fast-acting.

2.2 Productivity factor

This is one of the key parameters sprinkler sprinklers. It is designed to calculate the amount of water pouring through sprinkler at a certain pressure per unit of time. This is not difficult to do with the formula:

Q – water flow rate from the sprinkler, l/s P – pressure at the sprinkler, MPa K – productivity factor.

The value of the performance factor depends on the diameter of the sprinkler outlet: the larger the hole, the greater the coefficient.

In various foreign standards, there may be options for writing this coefficient, depending on the dimension of the parameters used. For example, not liters per second and MPa, but gallons per minute (GPM) and pressure in PSI, or liters per minute (LPM) and pressure in bar.

If necessary, all these quantities can be converted from one to another, using the conversion factors from Tables 1.

Table 1. Ratio between coefficients

For example, for the sprinkler SVV-12:

At the same time, it must be remembered that when calculating the water flow using K-factor values, it is necessary to use a slightly different formula:

2.3 Water distribution and irrigation intensity

All of the above requirements are repeated to a greater or lesser extent both in the ISO/FDIS6182-1 standard and in GOST R 51043. With the existing minor discrepancies, however, they are not of a fundamental nature.

Very significant, indeed fundamental differences between the standards relate to the parameters of water distribution over the protected area. It is these differences, which form the basis of the characteristics of the sprinkler, that basically predetermine the rules and logic of designing automatic fire extinguishing systems.

One of the most important parameters of the sprinkler is the intensity of irrigation, that is, the water consumption in liters per 1 m 2 of the protected area per second. The fact is that, depending on the size and combustible properties fire load for its guaranteed extinguishing, it is required to provide a certain intensity of irrigation.

These parameters were determined experimentally during numerous tests. Specific values ​​​​of irrigation intensity for the protection of premises of various fire loads are given in Table 2 NPB88.

Fire safety the object is an extremely important and responsible task, on the correct solution of which the lives of many people can depend. Therefore, the requirements for equipment that ensure the implementation of this task can hardly be overestimated and called unnecessarily cruel. In this case, it becomes clear why the basis for the formation of the requirements of Russian standards GOST R 51043, NPB 88 5 , GOST R 50680 6 laid down the principle of extinguishing fires one sprinkler.

In other words, if a fire occurs within the protected zone of the sprinkler, he alone must provide the required irrigation intensity and extinguish the beginning fire. fire. To accomplish this task, during the certification of the sprinkler, tests are carried out to check its intensity of irrigation.

To do this, within the sector, exactly 1/4 of the area of ​​the circle of the protected zone, measured banks are placed in a checkerboard pattern. The sprinkler is set to the origin of this sector and it is tested at a given water pressure.

Figure 5 Sprinkler test scheme according to GOST R 51043.

After that, the amount of water that ended up in the banks is measured, and p average irrigation intensity is calculated. According to the requirements of clause 5.1.1.3. GOST R 51043, on a protected area of ​​​​12 m 2, a sprinkler installed at a height of 2.5 m from the floor, at two fixed pressures of 0.1 MPa and 0.3 MPa, must provide irrigation intensity not less than indicated in table 2.

table 2. The required irrigation intensity of the sprinkler according to GOST R 51043.

Looking at this table, the question arises: what intensity should a sprinkler with d y 12 mm provide at a pressure of 0.1 MPa? After all, a sprinkler with such d y fits both the second line with the requirement of 0.056 dm 3 /m 2 ⋅s, and the third 0.070 dm 3 /m 2 ⋅s? Why is one of the most important sprinkler parameters so neglected?

To clarify the situation, let's try to carry out some simple calculations.

Let's say the diameter of the outlet in the sprinkler is slightly larger than 12 mm. Then according to the formula (3) Let us determine the amount of water pouring out of the sprinkler at a pressure of 0.1 MPa: 1.49 l/s. If all this water pours out exactly on the protected area of ​​12 m 2, then an irrigation intensity of 0.124 dm 3 /m 2 ⋅ s will be created. If we compare this figure with the required intensity of 0.070 dm 3 /m 2 ⋅ s pouring out of the sprinkler, it turns out that only 56.5% of the water meets the requirements of GOST and enters the protected area.

Now let's assume that the diameter of the outlet is slightly less than 12 mm. In this case, it is necessary to correlate the received irrigation intensity of 0.124 dm 3 /m 2 ⋅s with the requirements of the second line of table 2 (0.056 dm 3 /m 2 ⋅s). It turns out even less: 45.2%.

In the specialized literature 7 the parameters calculated by us are called the efficiency of consumption.

It is possible that the requirements of GOST contain only the minimum allowable requirements for the efficiency of the flow, below which the sprinkler, as part of fire extinguishing installations, cannot be considered at all. Then it turns out that the real parameters of the sprinkler should be contained in the technical documentation of the manufacturers. Why don't we find them there?

The fact is that in order to design sprinkler systems for various objects, it is necessary to know what intensity the sprinkler will create in certain conditions. First of all, depending on the pressure in front of the sprinkler and the height of its installation. Practical tests have shown that these parameters cannot be described by a mathematical formula, and a large number of experiments must be carried out to create such a two-dimensional data array.

In addition, there are several practical problems.

Let's try to imagine an ideal sprinkler with a flow efficiency of 99%, where almost all the water is distributed within the protected area.

Figure 6 Ideal distribution of water within the protected area.

On the figure 6 shows the ideal water distribution pattern for a fill with a COP of 0.47. It can be seen that only a small part of the water falls outside the protected area with a radius of 2 m (indicated by the dotted line).

Everything seems to be simple and logical, but questions begin when it is necessary to protect a large area with sprinklers. How to place sprinklers?

In one case, unprotected areas appear ( figure 7). In another, to cover unprotected areas, sprinklers must be placed closer, which leads to overlapping of part of the protected areas by neighboring sprinklers ( figure 8).

Figure 7 Arrangement of sprinklers without overlapping irrigation zones

Figure 8 Arrangement of sprinklers with overlapping of irrigation zones.

The overlap of protected areas leads to the fact that it is necessary to significantly increase the number of sprinklers, and, most importantly, much more water will be required for the operation of such a sprinkler AUPT. At the same time, in the event that fire if more than one sprinkler is activated, the amount of overflowing water will be clearly excessive.

A rather simple solution to this seemingly contradictory task is proposed in foreign standards.

The fact is that in foreign standards, the requirements for ensuring the necessary intensity of irrigation are imposed on the simultaneous operation of four sprinklers. Sprinklers are located in the corners of the square, inside which measuring containers are installed over the area.

Tests for sprinklers with different outlet diameters are carried out at different distances between sprinklers - from 4.5 to 2.5 meters. On the Figure 8 an example of the arrangement of sprinklers with an outlet diameter of 10 mm is shown. In this case, the distance between them should be 4.5 meters.

Figure 9 Sprinkler test scheme according to ISO/FDIS6182-1.

With this arrangement of sprinklers, water will fall into the center of the protected area if the distribution shape is significantly more than 2 meters, for example, such as on Figure 10.

Figure 10. Sprinkler water distribution schedule according to ISO/FDIS6182-1.

Naturally, with this form of water distribution, the average irrigation intensity will decrease in proportion to the increase in the irrigation area. But since the test involves four sprinklers at the same time, overlapping irrigation zones will provide a higher average irrigation intensity.

AT table 3 test conditions and requirements for irrigation intensity for a number of general purpose sprinklers according to the ISO/FDIS6182-1 standard are given. For convenience, the technical parameter for the amount of water in the tank, expressed in mm / min, is given in a more familiar dimension for Russian standards, liters per second / m 2.

Table 3 Irrigation rate requirements according to ISO/FDIS6182-1.

Outlet diameter, mm	Water consumption through the sprinkler, l/min	Arrangement of sprinklers		Irrigation intensity		Permissible number of containers with reduced water volume
		Protected area, m 2	Distance between orrows, m	mm/min in tank	l/s⋅m 2
10	50,6	20,25	4,5	2,5	0,0417	8 out of 81
15	61,3	12,25	3,5	5,0	0,083	5 out of 49
15	135,0	9,00	3,0	15,0	0,250	4 out of 36
20	90,0	9,00	3,0	10,0	0,167	4 out of 36
20	187,5	6,25	2,5	30,0	0,500	3 out of 25

To assess how high the level of requirements for the magnitude and uniformity of irrigation intensity within the protected square is, the following simple calculations can be made:

1. Let us determine how much water is poured out within the square of the irrigation area per second. It can be seen from the figure that a sector of a quarter of the irrigated area of ​​the sprinkler circle participates in the irrigation of the square, therefore four sprinklers pour onto the “protected” square the amount of water equal to that poured out from one sprinkler. By dividing the indicated water flow by 60, we get the flow in l / s. For example, for DN 10 at a flow rate of 50.6 l / min we get 0.8433 l / s.
2. Ideally, if all the water is evenly distributed over the area, the flow rate should be divided by the protected area to obtain the specific intensity. For example, 0.8433 l / s divided by 20.25 m 2, we get 0.0417 l / s / m 2, which exactly matches the standard value. And since it is impossible in principle to achieve an ideal distribution, it is allowed to have containers with a lower water content in an amount of up to 10%. In our example, these are 8 out of 81 cans. It can be recognized that this is a fairly high level of water distribution uniformity.

If we talk about controlling the uniformity of irrigation intensity according to the Russian standard, then the inspector will face a much more serious test of mathematics. According to the requirements of GOST R51043:

The average irrigation intensity of the water sprinkler I, dm 3 / (m 2 s), is calculated by the formula:

where i i - irrigation intensity in the i-th dimensional bank, dm 3 /(m 3 ⋅ s);
n is the number of measuring jars installed on the protected area. Irrigation intensity in the i-th dimensional bank i i dm 3 / (m 3 ⋅ s), is calculated by the formula:

where V i is the volume of water (aqueous solution) collected in the i-th measuring jar, dm 3;
t is the duration of irrigation, s. Irrigation uniformity, characterized by the value of the standard deviation S, dm 3 /(m 2 ⋅ s), is calculated by the formula:

Irrigation uniformity coefficient R is calculated by the formula:

Sprinklers are considered to have passed the test if the average irrigation intensity is not lower than the standard value with an irrigation uniformity coefficient of not more than 0.5 and the number of measuring cans with an irrigation intensity of less than 50% of the standard intensity does not exceed: two - for sprinklers of types B, H, U and four – for sprinklers of types Г, ГВ, ГН and ГУ.

The uniformity coefficient is not taken into account if the intensity of irrigation in measured banks is less than the standard value in the following cases: in four measured banks - for sprinklers of types B, N, U and six - for sprinklers of types G, G V, G N and G U.

But these requirements are no longer plagiarism of foreign standards! These are our native requirements. However, it should be noted that they also have disadvantages. However, in order to reveal all the disadvantages or advantages of this method of measuring the uniformity of irrigation intensity, more than one page will be needed. Perhaps this will be done in the next edition of the article.

Conclusion

1. A comparative analysis of the requirements for the technical characteristics of sprinklers in the Russian standard GOST R 51043 and the foreign standard ISO / FDIS6182-1 showed that they are almost identical in terms of sprinkler quality indicators.
2. Significant differences between the sprinklers are laid down in the requirements of various Russian standards on the issue of ensuring the necessary intensity of irrigation of the protected area with one sprinkler. In accordance with foreign standards, the required irrigation intensity must be ensured by the operation of four sprinklers simultaneously.
3. The advantage of the “single-sprinkler protection” method is the higher probability that a fire will be extinguished by a single sprinkler.
4. As disadvantages can be noted:

• more sprinklers are needed to protect the premises;
• for the operation of the fire extinguishing installation, significantly more water will be needed, in some cases its amount can increase significantly;
• delivery of large volumes of water entails a significant increase in the cost of the entire fire extinguishing system;
• lack of a clear methodology explaining the principles and rules for arranging sprinklers in a protected area;
• lack of necessary data on the actual intensity of irrigation of sprinklers, which prevents a clear implementation of the engineering calculation of the project.

Literature

1 GOST R 51043-2002. Automatic water and foam fire extinguishing installations. Sprinklers. General technical requirements. Test methods.

2 ISO/FDIS6182-1. Fire protection - Automatic sprinkler systems - Part 1: Requirements and test methods for sprinklers.

3 http://www.sprinklerreplacement.com/

4 SP 6. Fire protection system. Design norms and rules. Automatic fire alarm and automatic fire extinguishing. Draft final revision No171208.

5 NPB 88-01 Fire extinguishing and alarm systems. Design norms and rules.

6 GOST R 50680-94. Automatic water fire extinguishing installations. General technical requirements. Test methods.

7 Design of water and foam automatic fire extinguishing installations. L.M. Meshman, S.G. Tsarichenko, V.A. Bylinkin, V.V. Aleshin, R.Yu. Gubin; Under the general editorship of N.P. Kopylov. - M .: VNIIPO EMERCOM of the Russian Federation, 2002