How to provide the required irrigation intensity. Again, irrigation intensity and minimum flow. Thermal sensitivity of the lock

In the USSR, the main manufacturer of sprinklers was the Odessa factory "Spetsavtomatika", which produced three types of sprinklers mounted with a socket up or down, with a nominal outlet diameter of 10; 12 and 15 mm.

Based on the results of comprehensive tests, irrigation plots were constructed for these irrigators in a wide range of pressures and installation heights. In accordance with the data obtained, standards were established in SNiP 2.04.09-84 for their placement (depending on the fire load) at a distance of 3 or 4 m from each other. These standards are without changes made to NPB 88-2001.

At present, the bulk of irrigators comes from abroad, since Russian manufacturers of Spets-Avtomatika software (Biysk) and Ropotek CJSC (Moscow) are not able to fully satisfy the need for domestic consumers.

In prospectuses on foreign irrigators, as a rule, there is no data on most of the technical parameters regulated by domestic standards. In this regard, it is not possible to conduct a comparative assessment of the quality indicators of one-type products manufactured by various firms.

Certification tests do not provide an exhaustive check of the initial hydraulic parameters necessary for designing, for example, irrigation intensity diagrams within the protected area depending on the pressure and height of the sprinkler installation. As a rule, these data are also absent in the technical documentation, however, without this information it is not possible to correctly carry out design work on the AUP.

In particular, the most important irrigation parameter necessary for designing an AUP is the irrigation intensity of the protected area, depending on the pressure and height of the irrigator installation.

Depending on the design of the irrigator, the irrigation area may remain unchanged, decrease or increase with increasing pressure.

For example, irrigation plots for a universal sprinkler of the CU / P type, installed upside down, practically change little from the supply pressure in the range 0.07-0.34 MPa (Fig. IV. 1.1). On the contrary, the irrigation diagrams of the irrigator of this type, installed with the outlet down, change more intensively when the supply pressure changes within the same limits.

If the irrigated area of \u200b\u200bthe irrigator remains unchanged with a change in pressure, then within the irrigated area is 12 m 2 (circle R ~ 2 m) it is possible by calculation to establish the pressure P t at which the irrigation intensity required by the project i m is provided:

where R n and i n - pressure and the corresponding value of the intensity of irrigation according to GOST R 51043-94 and NPB 87-2000.

The values \u200b\u200bof i n and R n depend on the diameter of the outlet.

If the irrigation area decreases with increasing pressure, then the irrigation intensity increases more significantly compared to equation (IV. 1.1), however, it must be borne in mind that the distance between the sprinklers should also be reduced.

If the irrigation area increases with increasing pressure, then the irrigation intensity can slightly increase, remain unchanged, or decrease significantly. In this case, the calculation method for determining the irrigation intensity depending on pressure is unacceptable, therefore, the distance between the sprinklers can be determined using only irrigation plots.

The cases of lack of efficiency in extinguishing AUPs noted in practice are often the result of incorrect calculation of hydraulic circuits of AUPs (insufficient intensity of irrigation).

The irrigation diagrams given in separate prospectuses of foreign companies characterize the visible border of the irrigation zone, not being a numerical characteristic of the irrigation intensity, and only mislead specialists of design organizations. For example, on the irrigation plots of a universal sprinkler of the CU / P type, the boundaries of the irrigation zone are not indicated by numerical values \u200b\u200bof the irrigation intensity (see Fig. IV.1.1).

A preliminary assessment of such plots can be made as follows.

On schedule q \u003d f (K, P) (Fig. IV. 1.2) the flow rate from the sprinkler is determined at a productivity factor TO, specified in the technical documentation, and pressure on the corresponding diagram.

For sprinkler at TO \u003d 80 and P \u003d 0.07 MPa flow rate is q p \u003d 007 ~ 67 l / min (1.1 l / s).

According to GOST R 51043-94 and NPB 87-2000 at a pressure of 0.05 MPa, concentric irrigation irrigators with an outlet diameter of 10 to 12 mm should provide an intensity of at least 0.04 l / (cm 2).

We determine the flow rate from the sprinkler at a pressure of 0.05 MPa:

q p \u003d 0.05 \u003d 0.845 q p ≈ \u003d 0.93 l / s. (IV. 1.2)

Assuming irrigation within the specified irrigation area of \u200b\u200bradius R≈3.1 m (see Fig. IV. 1.1, a) the uniform and all extinguishing agent is distributed only over the protected area, we determine the average irrigation intensity:

Thus, this irrigation intensity within the given plot does not correspond to the normative value (at least 0.04 l / (s * m 2) is necessary. In order to establish whether this design of the irrigator meets the requirements of GOST R 51043-94 and NPB 87- 2000 on an area of \u200b\u200b12 m 2 (radius ~ 2 m), appropriate tests are required.

For the qualified design of the AUP, irrigation diagrams should be presented in the technical documentation for irrigators depending on the pressure and installation height. Similar plots of a universal sprinkler of the RPTK type are shown in Fig. IV. 1.3, and sprinklers produced by SP “Spetsavtomatika” (Biysk) - in Appendix 6.

According to the given irrigation diagrams for this design of irrigators, it is possible to draw appropriate conclusions about the effect of pressure on the irrigation intensity.

For example, if the RPTK sprinkler is installed with the outlet upside down, then with an installation height of 2.5 m, the irrigation intensity is practically independent of pressure. Within the area of \u200b\u200bthe zone of radius 1.5; At 2 and 2.5 m, the irrigation intensity with a pressure increase of 2 times increases by 0.005 l / (s * m 2), i.e. by 4.3-6.7%, which indicates a significant increase in the irrigation area. If with an increase in pressure by 2 times the irrigation area will remain unchanged, then the irrigation intensity should increase by 1.41 times.

When the RPTC sprinkler is installed with the outlet down, the irrigation intensity increases more significantly (by 25–40%), which indicates a slight increase in the irrigation area (with a constant irrigation area, the intensity should increase by 41%).

FEDERAL BUDGETARY EDUCATIONAL INSTITUTION OF HIGHER PROFESSIONAL EDUCATION

"CHUVASH STATE PEDAGOGICAL UNIVERSITY

them. AND I. YAKOVLEVA »

Department of Fire Safety

Laboratory work No. 1

discipline: "Fire fighting automation"

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

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

faculty of Physics and Mathematics

Checked: Sintsov S.I.

Cheboksary 2013

Determination of irrigation intensity of water extinguishing installations

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

2. Brief theoretical information

The intensity of water irrigation 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 units into operation and during operation at least once every five years. The following methods for determining irrigation intensity are available.

1. According to GOST R 50680-94, the irrigation intensity is determined in the selected area of \u200b\u200bthe installation during operation of one sprinkler for sprinkler and four sprinklers for deluge installations at design pressure. The selection of sites for testing sprinkler and deluge installations is carried out by representatives of the customer and Gospozhnadzor on the basis of approved regulatory documentation.

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

where W under is the volume of water collected in the pan during the operation of the installation in steady state, l; τ is the duration of the installation, s; F is the area of \u200b\u200bthe pallet equal to 0.25 m 2.

The irrigation intensity at each control point should be no lower than the normative (table. 1-3 NPB 88-2001 *).

This method requires spillage of water over the entire area of \u200b\u200bthe settlement sites and in the conditions of the existing enterprise.

2. Determination of irrigation intensity using a measuring tank. Using the design data (standard irrigation intensity; actual area occupied by the irrigator; diameters and lengths of pipelines), a design diagram is compiled and the required head for the sprinkler being tested and the corresponding head in the supply pipe at the control unit are calculated. Then the sprinkler sprinkler changes to deluge. Under the sprinkler, a measuring tank is installed, connected by a sleeve to the sprinkler. The valve opens in front of the control unit valve and, using a pressure gauge showing the pressure in the supply pipe, the calculated pressure is set. In the steady state, the flow rate is measured from the sprinkler. These operations are repeated for each subsequent sprinkler to be tested. The irrigation intensity I l / (s * m 2) at each control point is determined by the formula and should not be lower than the normative:

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

Upon receipt of unsatisfactory results (at least one of the irrigators), the reasons must be identified and eliminated, and then the tests are repeated.

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

Rationing of water consumption, to extinguish fires in high-rise shelving warehouses. UDC B14.844.22

L. Meshman

V. Bylinkin

ph.D., Leading Researcher,

R. Gubin

senior Researcher,

E. Romanova

researcher

Currently, the main baseline characteristics for calculating the water flow rate for automatic fire extinguishing installations (AUP) are the standard values \u200b\u200bof the irrigation intensity or pressure of the dictating sprinkler. Irrigation intensity is used in regulatory documents irrespective of the design of irrigators, and pressure is applied only to a specific type of irrigator.

Irrigation intensities are given in SP 5.13130 \u200b\u200bfor all groups of premises, including warehouse buildings. This implies the use of sprinkler AUP under the cover of the building.

However, the accepted values \u200b\u200bof irrigation intensity depending on the group of premises, storage height and type of extinguishing agent given in table 5.2 of SP 5.13130 \u200b\u200bare not amenable to logic. For example, for a group of rooms 5, with an increase in the storage height from 1 to 4 m (per meter of height) and from 4 to 5.5 m, the intensity of irrigation with water increases proportionally to 0.08 l / (s-m2).

It would seem that a similar approach to rationing the supply of extinguishing agent for extinguishing a fire should extend to other groups of rooms and to extinguish a fire with a foaming agent, but this is not observed.

For example, for a group of rooms 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 shelf storage height, and when the storage height is from 4 to 5.5 m, the intensity irrigation increases 4 times, i.e. at 0.16 l / (s-m2), and is 0.32 l / (s-m2).

For the group of rooms 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), over 2 to 4 m - intensity does not change, but with a storage height of more than 4-5.5 m, the irrigation intensity changes by 0.1 l / (s-m2) and is 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 changes by 0.12 l / (s-m2), over 2-3 m - 0.04 l / (s-m2), and then more than 3 to 4 m and more than 4 to 5.5 m - 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 extinguishing agent jets do not, as a rule, directly affect the combustion zone (the exception is a fire at the highest tier). Part of the water dispersed from the sprinkler spreads over the horizontal surface of the boxes and flows down, the rest, not falling on the boxes, forms a vertical protective curtain. Partially oblique jets fall into the free internal rack space and moisten the goods that are not packed in boxes, or the side surface of the boxes. Therefore, if for open surfaces the dependence of the irrigation intensity on the type of fire load and its specific load is not in doubt, then when extinguishing shelving warehouses this dependence does not appear so noticeably.

Nevertheless, if we allow some proportionality in the increase in irrigation intensity depending on the storage height and room height, then it becomes possible to determine the irrigation intensity not through discrete values \u200b\u200bof the storage height and room height, as presented in SP 5.13130, but through a continuous function, expressed the equation

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

i55 - irrigation intensity 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);

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

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

The coefficient of variation of the storage height f for groups of rooms 5 is taken 20% less than for groups of rooms b (by analogy with SP 5.13130).

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

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

Therefore, designers are uncomfortable when deciding on the design pressure value of a dictating sprinkler. In addition, it is not clear what height to determine the irrigation intensity to be taken as the calculated: 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 irrigation intensity: on the area of \u200b\u200ba circle with a diameter equal to the distance between the irrigators, or on the entire area irrigated by the irrigator, or taking into account mutual irrigation by adjacent irrigators.

For fire protection of high-rise rack warehouses, sprinkler AUPs are now being widely used, the irrigators of which are located under the warehouse cover. Such a technical solution requires a large flow of water. For these purposes, special sprinklers of both domestic production, 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, are used.

In service stations for SOBR sprinklers, in prospectuses for ESFR sprinklers of Tyco and Viking firms, the main parameter is the pressure of the sprinkler depending on its type (SOBR-17, SOBR-25, ESFR-17, ESFR-25, VK503, VK510, etc. n.), depending on the type of goods stored, storage height and room height. 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 feasibility of using any sprinkler designs developed in the future? It turns out that you can, if you use the pressure or flow rate of the dictating sprinkler as a key parameter, and as an additional parameter, the irrigation intensity over a given area at a standard height of the sprinkler 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 irrigators: the area on which the irrigation intensity is determined for general irrigators is 12 m2 (diameter ~ 4 m), for special irrigators - 9, b m2 ( diameter ~ 3.5 m), sprinkler installation height 2.5 m, pressure 0.1 and 0.3 MPa. Moreover, information on the intensity of irrigation of each type of irrigator obtained in the process of certification testing must be indicated in the passport for each type of irrigator. With the specified initial parameters for high-rise rack storage, the irrigation intensity should be no less than that given in table 3.

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

In relation to high-altitude warehouses (with a storage height of more than 5.5 m), two initial conditions can be accepted for calculating the normative value of the flow of a dictating sprinkler:

1. With a storage height of 5.5 m and a room height of b, 5 m.

2. With a storage height of 12.2 m and a room height of 13.7 m. The first reference point (minimum) is established on the basis of the data of SP 5.131301 for irrigation intensity and total consumption of water AUP. For a group of premises, the irrigation intensity is at least 0.5 l / (s-m2) and the total flow rate is at least 90 l / s. The flow rate of a dictating general purpose irrigator according to the standards of SP 5.13130 \u200b\u200bat such an irrigation intensity is at least b, 5 l / s.

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

With approximately equal flow rates of the irrigators 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 an additional consumption of extinguishing agent. Therefore, it is advisable to focus on the hydraulic parameters of the sprinklers SOBR-25, ESFR-25, VK510.

For groups of rooms 5 and b (in accordance with SP 5.13130) of high-rise shelving warehouses, it is proposed to calculate the equation for calculating the flow rate of a dictating water sprinkler AUP 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 dosing sprinkler ESFR-25 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 on FM, i.e. 0.34 MPa:

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

КРФ - coefficient of productivity in dimension according to GOST R 51043, l / (s-m water.st.0.5);

KISO - productivity coefficient in dimension according to ISO 6182-7, l / (min-bar0.5); p - pressure at the irrigator, MPa.

The flow rate of the dictating sprinkler for room group 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 \u003d 10 l / s.

For room groups 5, the flow rate of the dictating sprinkler is q55 \u003d 5.3 l / s, and for room groups 6 - q55 \u003d 6.5 l / s.

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

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

The ratios of the pressures given in, with the flow rate calculated at these pressures for the sprinklers ESFR-25 and SOBR-25, are presented in table 6. The calculation of the flow rate for groups 5 and 6 is performed according to formula (3).

As follows from table 7, the flow rate of the dictating sprinkler for room groups 5 and 6, calculated by the formula (3), is quite well correlated with the flow rate of the sprinklers ESFR-25, calculated by the formula (2).

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

Thus, the initial parameters of normative documents for determining the total consumption of AUP as applied to high-rise rack warehouses in which sprinklers are placed under the cover can be:

■ irrigation intensity;

■ pressure from the dictating sprinkler;

■ flow of dictating sprinkler.

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

The use of the “flow rate of the dictating sprinkler” as the dominant parameter is also advisable to enter into all regulatory documents, in which the irrigation intensity is used as the main hydraulic parameter.

Table 4

Table 5

Table 6

LITERATURE:

1. SP 5.13130.2009 “Fire protection systems. Automatic fire alarm and fire extinguishing installations. Norms and design rules. "

2. STO 7.3-02-2009. The organization’s standard for the design of automatic water extinguishing installations using SOBR sprinklers in high-altitude warehouses. General technical requirements. Biysk, CJSC PO Special Automation, 2009.

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

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 systems. Teaching aid. M .: VNIIPO, 2002, 314 p.

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