FEDERAL STATE BUDGET EDUCATIONAL INSTITUTION OF HIGHER PROFESSIONAL EDUCATION

"CHUVASH STATE PEDAGOGICAL UNIVERSITY

them. AND I. YAKOVLEV"

Department fire safety

Laboratory work No. 1

discipline: "Fire extinguishing automation"

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

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

Faculty of Physics and Mathematics

Checked by: Sintsov S.I.

Cheboksary 2013

Determining the intensity of irrigation of water fire extinguishing installations

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

2. Brief theoretical information

The intensity of water spraying 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 installations into operation and during operation at least once every five years. There are the following methods for determining irrigation intensity.

1. According to GOST R 50680-94, irrigation intensity is determined at the selected installation site when one sprinkler for sprinklers and four sprinklers for deluge installations are operating at the 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 area selected for testing, metal pallets measuring 0.5 * 0.5 m and side heights of at least 0.2 m must be installed at control points. The number of control points must be at least three, which must be located in the most unfavorable places for irrigation. Irrigation intensity I l/(s*m2) at each control point is determined by the formula:

where W under is the volume of water collected in the pan during operation of the installation in steady state, l; τ – duration of operation of the installation, s; F – pallet area equal to 0.25 m2.

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

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

2. Determination of irrigation intensity using a measuring container. Using design data (standard irrigation intensity; actual area occupied by the sprinkler; diameters and lengths of pipelines), a design diagram is drawn up and the required pressure at the sprinkler being tested and the corresponding pressure in the supply pipeline at the control unit are calculated. Then the sprinkler is changed to a deluge. A measuring container is installed under the sprinkler, connected by a hose to the sprinkler. The valve in front of the valve of the control unit opens and the pressure obtained by calculation is established using a pressure gauge showing the pressure in the supply pipeline. At a steady flow rate, the flow rate from the sprinkler is measured. These operations are repeated for each subsequent sprinkler being tested. Irrigation intensity I l/(s*m2) 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 container, l, measured over time τ, s; F – area protected by the sprinkler (according to the design), m2.

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

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

1. Quality indicators

1.1 Sealing

This is one of the main indicators faced by the user of a sprinkler system. Indeed, a sprinkler with poor sealing can cause a lot of trouble. No one will like it if water suddenly starts dripping onto people, expensive equipment or goods. And if loss of tightness occurs due to spontaneous destruction of the 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 many years, allow us to be confident in their reliability.

The main element of the sprinkler, which ensures the tightness of the sprinkler under the most severe operating conditions, is a disc 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 be constantly under sufficiently high pressure, which is ensured during assembly with a locking screw (1) . Over time, under the influence of this pressure, a slight deformation of the sprinkler body may occur, which, however, would be sufficient to break the tightness.

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

Figure 2. Sprinkler with rubber gasket.

However, it was not taken 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 sealed surfaces. Therefore, when fire, after the destruction of the heat-sensitive element, the sprinkler cover remains tightly glued to the body and water does not flow from the sprinkler.

Such cases have been recorded during fires at many facilities in the United States. After this, the manufacturers carried out a large-scale campaign to recall and replace all sprinklers with rubber sealing rings 3 . IN Russian Federation use of sprinklers with rubber seal forbidden. 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 whole line tests to ensure tightness.

Each sprinkler is tested under hydraulic (1.5 MPa) and pneumatic (0.6 MPa) pressure, and is also tested for resistance to water hammer, that is, sudden increases in pressure up to 2.5 MPa.

Vibration tests provide confidence that sprinklers will perform reliably under the harshest operating conditions.

1.2 Durability

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 design elements is determined by tests for resistance to the effects of a foggy environment of salt spray, aqueous solution ammonia and sulfur dioxide.

The shock resistance of the sprinkler should ensure the integrity of all its elements when dropped onto a concrete floor from a height of 1 meter.

The sprinkler outlet must be able to withstand the impact water, leaving it under a pressure of 1.25 MPa.

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

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

1.3 Reliability of the thermal lock

One of the most critical elements of a sprinkler is the sprinkler's thermal lock. The technical characteristics and quality of this element largely determine successful work sprinkler The timeliness of fire extinguishing and the absence of false alarms in standby mode. Over the long history of the sprinkler system, many types of thermal lock designs have been proposed.




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

Fusible thermal locks with a heat-sensitive element based on Wood's alloy, which softens at a given temperature and the lock disintegrates, as well as thermal locks that use a glass heat-sensitive bulb have passed the test of time. Under the influence 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 sprinklers with different types 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 lower sprinklers temperature range the response temperature deviation should not exceed 3°C.

The thermal lock must be resistant to thermal shock (sudden temperature rise 10°C below the nominal operating temperature).

The thermal resistance of the thermal lock is tested by gradually heating the temperature to 5°C below the nominal operating temperature.

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

Both the glass bulb and the fusible element are subject to strength testing. For example, a glass flask must withstand a load six times greater than its operating load. The fuse element has a limit of fifteen.

2. Purpose indicators

2.1 Thermal sensitivity of the lock

According to GOST R 51043, the sprinkler response time must be checked. 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 this element is to heat. Together with another parameter - C (conductivity factor - measure thermal conductivity between the temperature-sensitive element and the sprinkler design elements) they form one of the most important characteristics sprinkler - response time.




Figure 4. The boundaries of the zones that determine the speed of the sprinkler.

Figure 4 indicates areas that characterize:

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

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

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

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

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

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

A person with knowledge of mathematics within school curriculum, it is easy to notice that when converting the form of a formula from a foreign standard (it is not clear why this was done, perhaps to make it look less like plagiarism?) the minus sign in the power of the multiplier ν of 0.5, which is in the numerator of the fraction, was omitted.

At the same time, it is necessary to note the positive aspects in modern rule-making. Until recently, the sensitivity of a sprinkler could easily be considered a quality parameter. The now newly developed (but not yet put into effect) SP 6 4 already contains instructions on 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 the requirement for the temperature sensitivity of a sprinkler is established intentionally or due to inaccuracy only on the basis of the coefficient of thermal inertia of the temperature-sensitive element without taking into account the coefficient of heat loss due to thermal conductivity. And this at a time when, according to international standard(Fig. 4), sprinklers with heat loss coefficient due to thermal conductivity more than 1.0 (m/s) 0.5 are no longer considered fast-acting.

2.2 Productivity factor

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

Q – water flow from the sprinkler, l/sec P – pressure at the sprinkler, MPa K – performance coefficient.

The value of the performance coefficient 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 conversion factors from Tables 1.

Table 1. Relationship between coefficients

For example, for the SVV-12 sprinkler:

It must be remembered that when calculating water consumption using K-factor values, you must use a slightly different formula:

2.3 Water distribution and irrigation intensity

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

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

One of the most important parameters of a sprinkler is irrigation intensity, that is, water consumption in liters per 1 m2 of protected area per second. The fact is that depending on the size and combustible properties fire load To guarantee its extinguishing, it is necessary to provide a certain intensity of irrigation.

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

Ensuring fire safety object is an extremely important and responsible task, from the right decision on which the lives of many people may depend. Therefore, the requirements for equipment that ensures 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 is GOST R 51043, NPB 88 5 , GOST R 50680 6 the principle of extinguishing is laid down fires one sprinkler.

In other words, if a fire occurs within the protected area of ​​the sprinkler, it alone must provide the required irrigation intensity and extinguish the beginning fire. To accomplish this task, when certifying a sprinkler, tests are carried out to verify its irrigation intensity.

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

Figure 5. Sprinkler testing scheme according to GOST R 51043.

After this, the amount of water that ended up in the jars is measured, and the average irrigation intensity is calculated. According to the requirements of paragraph 5.1.1.3. GOST R 51043, on a protected area of ​​12 m2, 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 an irrigation intensity of no less than specified in table 2.

table 2. 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 line of 0.070 dm 3 /m 2 ⋅s? Why is one of the most important parameters of a sprinkler treated so carelessly?

To clarify the situation, let's try to carry out a series of simple calculations.

Let's say the diameter of the outlet hole in the sprinkler is slightly larger than 12 mm. Then according to the formula (3) Let's 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 exactly onto 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 falls on the protected area.

Now let's assume that the diameter of the outlet hole is slightly less than 12 mm. In this case, it is necessary to correlate the resulting 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 we calculated are called the coefficient beneficial use consumption

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

The fact is that in order to design sprinkler systems for various objects, it is necessary to know what intensity the sprinkler system will create under 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 to create such a two-dimensional data array it is necessary to carry out a large number of experiments.

In addition, several other practical problems arise.

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

Figure 6. Ideal distribution of water within the protected area.

On Figure 6 shows the ideal water distribution pattern for a sprinkler with a performance coefficient 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 simple and logical, but the questions begin when it is necessary to protect with sprinklers large area. How should sprinklers be placed?

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

Figure 7. Arrangement of sprinklers without blocking irrigation zones

Figure 8. Arrangement of sprinklers with overlap of irrigation zones.

Covering the protected areas leads to the need to significantly increase the number of sprinklers, and, most importantly, the operation of such a sprinkler AUPT will require much more water. Moreover, if fire If more than one sprinkler works, the amount of water flowing out will be clearly excessive.

A fairly simple solution to this seemingly contradictory problem is proposed in foreign standards.

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

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

Figure 9. Sprinkler testing 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 in 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, the overlap of irrigation zones will provide a higher average irrigation intensity.

IN table 3 test conditions and requirements for irrigation intensity for a number of sprinklers are given general purpose according to ISO/FDIS6182-1 standard. For convenience, the technical parameter for the amount of water in the container, expressed in mm/min, is given in a dimension more familiar to Russian standards, liters per second/m2.

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

Outlet diameter, mm	Water flow through the sprinkler, l/min	Arrangement of sprinklers		Irrigation intensity		Permissible number of containers with reduced water volume
		Protected area, m 2	Distance between vegetation, m	mm/min in tank	l/s⋅m 2
10	50,6	20,25	4,5	2,5	0,0417	8 of 81
15	61,3	12,25	3,5	5,0	0,083	5 of 49
15	135,0	9,00	3,0	15,0	0,250	4 of 36
20	90,0	9,00	3,0	10,0	0,167	4 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 size and uniformity of irrigation intensity inside the protected square is, you can make the following simple calculations:

1. Let us determine how much water is poured 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 is involved in irrigating the square, therefore four sprinklers pour onto the “protected” square an amount of water equal to that poured out from one sprinkler. Dividing the indicated water flow rate by 60, we obtain the flow rate in l/sec. For example, for DN 10 at a flow rate of 50.6 l/min we get 0.8433 l/sec.
2. Ideally, if all the water is evenly distributed over the area, to obtain the specific intensity, the flow rate should be divided by the protected area. For example, we divide 0.8433 l/sec by 20.25 m2, we get 0.0417 l/sec/m2, which exactly coincides with the standard value. And since ideal distribution is in principle impossible to achieve, the presence of containers with a lower water content of up to 10% is allowed. In our example, this is 8 out of 81 jars. You can admit it's enough high level uniform distribution of water.

If we talk about monitoring 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 using the formula:

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

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

Irrigation uniformity coefficient R is calculated using the formula:

Sprinklers are considered to have passed the tests if the average irrigation intensity is not lower than the standard value with an irrigation uniformity coefficient of no more than 0.5 and the number of measuring jars with an irrigation intensity of less than 50% of the standard intensity does not exceed: two - for sprinklers of types B, N, U and four – for sprinklers of types G, G V, G N and G U.

The uniformity coefficient is not taken into account if the intensity of irrigation in measuring banks is less than the standard value in the following cases: in four measuring banks - for sprinklers of types V, 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 identify 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. Comparative analysis of the requirements for technical specifications sprinklers in the Russian standard GOST R 51043 and foreign ISO/FDIS6182-1, showed that they are almost identical in terms of sprinkler quality indicators.
2. Significant differences between sprinklers lie in the requirements of different Russian standards on the issue of ensuring the required 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 “one sprinkler protection” method is the higher probability that the fire will be extinguished by one sprinkler.
4. The disadvantages include:

• more sprinklers are required 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 several times;
• 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 placing sprinklers in the protected area;
• lack of necessary data on the actual intensity of irrigation of sprinklers, which prevents the accurate implementation of the engineering calculations of the project.

Literature

1 GOST R 51043-2002. Automatic water and foam fire extinguishing systems. Sprinklers. Are common 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. Final draft draft No.171208.

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

6 GOST R 50680-94. Automatic water fire extinguishing systems. 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. Kopylova. – M.: VNIIPO EMERCOM of the Russian Federation, 2002.

Selection of fire extinguishing agent, fire extinguishing method and type automatic installation fire extinguishing

Possible OTVs are selected in accordance with NPB 88-2001. Taking into account the information on the applicability of fire protection equipment for fire control equipment, depending on the class of fire and the properties of the located material assets I agree with the recommendations for extinguishing class A1 fires (A1- burning solids accompanied by smoldering) will do water mist TRV.

In the calculation graphic task we accept AUP-TRV. The residential building in question will have a water-filled stringer (for rooms with a minimum air temperature of 10˚C and above). Sprinkler installations are accepted in rooms with high fire hazard. The design of TRV installations must be carried out taking into account the architectural planning solutions of the protected premises and technical parameters, technical installations TRVs given in the documentation for sprayers or modular TRV installations. Parameters of the designed sprinkler AUP (irrigation intensity, waste water consumption, minimum irrigation area, duration of water supply and maximum distance between sprinklers, we determine in accordance with. In section 2.1 there was a certain group of premises in the RGZ. To protect premises, you should use B3 – “Maxstop” sprinklers.

Table 3

Fire extinguishing installation parameters.

2.3. Tracing of fire extinguishing systems.

The figure shows the routing diagram, 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 clarifying the location of a building fire, as well as to turn on warning and smoke removal systems, it is recommended to install liquid flow alarms with a response pattern on the supply pipelines. For group 4 minimum distance from the top edge of objects to the sprinklers should be 0.5 meters. The distance from the sprinkler outlet installed vertically to the floor plane should be from 8 to 40 cm. In the designed AUP we take this distance 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 based on the result of a hydraulic calculation.

3. Hydraulic calculation of the fire extinguishing system.

Hydraulic calculation of the sprinkler network is carried out for the purpose of:

1. Determination of water flow

2. Comparison specific consumption irrigation intensity with regulatory requirements.

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

Hydraulic calculation of a fire-fighting water supply system comes down to solving three main problems:

1. Determination of pressure at the inlet to the fire-fighting water supply (on the axis of the outlet pipe, pump). If the estimated water flow rate is specified, the pipeline routing diagram, their length and diameter, as well as the type of fittings. In this case, the calculation begins with determining the pressure loss during water movement depending on the diameter of the pipelines, etc. The calculation ends with choosing the pump brand based on the estimated water flow and pressure at the beginning of installation

2. Determination of water flow based on a given pressure at the beginning of the fire-fighting pipeline. The calculation begins with determining the hydraulic resistance of all pipeline elements and ends with establishing the water flow from a given pressure at the beginning of the fire water supply.

3. Determination of the diameter of the pipeline and other elements based on the calculated water flow and pressure at the beginning of the pipeline.

Determination of the required pressure at a given irrigation intensity.

Table 4.

Parameters of Maxtop sprinklers

In the section, a sprinkler AUP was adopted; accordingly, we accept that sprinklers of the SIS-PN 0 0.085 brand will be used - sprinklers, water sprinklers, special purpose with concentric flow, installed vertically without decorative covering with a performance coefficient of 0.085, a nominal response temperature of 57 o, the calculated water flow in the dictating sprinkler is determined by the formula:

The performance coefficient is 0.085;

The required free head is 100 m.

3.2. Hydraulic calculation of separation and supply pipelines.

For each fire extinguishing section, the most remote or highest protected zone is determined, and hydraulic calculations are carried out specifically for this zone within the calculated area. In accordance with the completed layout of the fire extinguishing system, it is a dead-end configuration, not symmetrical with the morning water supply, and not combined. The free pressure at the dictating sprinkler is 100 m, the pressure loss at the supply section is equal to:

Section length of the 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 brand 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 loss of pressure 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 for water-filled installations must be made of galvanized and of stainless steel, the diameter of the pipeline is determined by the formula:

Area water consumption, m 3 /s

Speed ​​of water movement m/s. we accept movement speed from 3 to 10 m/s

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

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

Table 5.

3.3 Determination of the required pressure in the system

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

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

L. Meshman

V. Bylinkin

Ph.D., leading researcher,

R. Gubin

Senior Researcher,

E. Romanova

Researcher

Currently, the main initial characteristics used to calculate water flow for automatic fire extinguishing installations (AFS) are the standard 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 warehouse buildings. This implies the use of a sprinkler AUP 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 SP 5.13130, defy logic. For example, for group of premises 5, with an increase in storage height from 1 to 4 m (for each meter of height) and from 4 to 5.5 m, the intensity of water irrigation increases proportionally by 0.08 l/(s-m2).

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

For example, for group of premises 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 with 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 group of premises 6, the increase in water irrigation intensity is 0.16 l/(s-m2) to 2 m, from 2 to 3 m - only 0.08 l/(s-m2), over 2 to 4 m - intensity does not change, and when the storage height is above 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), above 1-2 m it changes by 0.12 l/(s-m2), above 2-3 m - by 0.04 l/(s-m2), and then from above 3 to 4 m and from above 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, jets of extinguishing agent do not directly affect the combustion zone, as a rule (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 enter the free space inside the shelving and wet the goods 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 appear so noticeably.

However, if we assume 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 room height, as presented in SP 5.13130, but through a continuous function expressed equation

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

i55 - intensity of irrigation with a dictating sprinkler at a storage height of 5.5 m and a room height of no more than 10 m (according to SP 5.13130), l/(s-m2);

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

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

The coefficient of variation of storage height f for groups of premises 5 is assumed to be 20% less than for groups of premises b (by analogy with SP 5.13130).

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

By doing hydraulic calculations distribution network of the AUP, 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 irrigation intensity can be determined only from a family of irrigation diagrams. But sprinkler manufacturers, as a rule, do not provide irrigation diagrams.

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

For fire protection of high-rise rack warehouses, sprinkler AUPs are now beginning to be widely used, the sprinklers of which are located under the warehouse covering. This technical solution requires high flow rate water. For these purposes, special sprinklers are used, such as 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.

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, 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 sprinkler design, to use some generalized parameter to assess the possibility of using any sprinkler designs developed in the future? It turns out that it is possible 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 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 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 during 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 must be no less than that given in Table 3.

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

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

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 reference point (minimum) is established based on data from SP 5.131301 on irrigation intensity and total consumption of water AUP. For group of rooms 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 standards of SP 5.13130 ​​at this irrigation intensity is at least 6.5 l/s.

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

With approximately equal flow rates of SOBR-17, ESFR-17, VK503 and SOBR-25, ESFR-25, VK510 sprinklers for identical warehouse characteristics, SOBR-17, ESFR-17, VK503 require more high 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 SOBR-25, ESFR-25, VK510 sprinklers.

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 automatic control units is proposed to be calculated using 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 dictating sprinkler ESFR-25 must be no less than: according to NFPA-13 0.28 MPa, according to FM 8-9 and FM 2-2 0.34 MPa. Therefore, we take the flow rate of the dictating sprinkler for group of rooms 6 taking into account the pressure according to FM, i.e. 0.34 MPa:

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

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

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

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

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

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

The relationship between the pressures given in and the flow rate calculated at these pressures for the ESFR-25 and SOBR-25 sprinklers is presented in Table 6. The flow rate for groups 5 and 6 is calculated using formula (3).

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

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

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

■ irrigation intensity;

■ pressure at the dictating sprinkler;

■ flow rate of dictating sprinkler.

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

It is advisable to introduce the use of “dictating sprinkler flow rate” as the dominant parameter in all regulations, 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 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. Design norms and rules."

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

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

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. Educational and methodological manual. M.: VNIIPO, 2002, 314 p.

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

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

Based on the results of comprehensive tests, irrigation diagrams were constructed for these sprinklers over 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 included without changes in NPB 88-2001.

Currently, the main volume of sprinklers comes from abroad, since Russian manufacturers PO Spets-Avtomatika (Biysk) and CJSC Ropotek (Moscow) are not able to fully meet the domestic demand for them consumers.

Prospects for foreign sprinklers, as a rule, do not contain data on most technical parameters regulated by domestic standards. In this regard, carry out a comparative assessment of the quality indicators of the same type of products manufactured various companies, does not seem possible.

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

In particular, the most important parameter sprinklers, necessary for the design of AUP, is the intensity of irrigation of the protected area, depending on the pressure and height of the sprinkler installation.

Depending on the design of the sprinkler, the irrigation area may remain unchanged, decrease or increase as the pressure increases.

For example, irrigation diagrams of a universal sprinkler type CU/P, installed by socket upward, change almost slightly from the supply pressure in the range of 0.07-0.34 MPa (Fig. IV. 1.1). On the contrary, the irrigation diagrams of a sprinkler of this type, installed with the rosette facing down, change more intensively when the supply pressure changes within the same limits.

If the irrigated area of ​​the sprinkler remains unchanged when the pressure changes, then within the irrigation area of ​​12 m2 (circle R ~ 2 m) you can set the pressure Р t by calculation, at which the irrigation intensity i m required by the project is ensured:

Where R n and i n - pressure and the corresponding irrigation intensity value in accordance with GOST R 51043-94 and NPB 87-2000.

Values ​​i n and R n depend on the diameter of the outlet.

If the irrigation area decreases with increasing pressure, then the intensity of irrigation increases more significantly compared to equation (IV. 1.1), however, it is necessary to take into account that the distance between the sprinklers should also decrease.

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

Cases of lack of effectiveness of fire extinguishing fires observed in practice are often the result of incorrect calculation of hydraulic fire circuits (insufficient irrigation intensity).

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

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

On schedule q = f(K, P)(Fig. IV. 1.2) the flow rate from the sprinkler is determined at the performance coefficient TO, specified in the technical documentation, and the pressure on the corresponding diagram.

For sprinkler at TO= 80 and P = 0.07 MPa flow rate is q p =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 sprinklers with an outlet diameter of 10 to 12 mm must 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=0.05 = 0.845 q p ≈ = 0.93 l/s. (IV. 1.2)

Assuming that irrigation within the specified irrigation area with radius R≈3.1 m (see Fig. IV. 1.1, a) uniform and all fire extinguishing agent distributed only over the protected area, we determine the average irrigation intensity:

Thus, this irrigation intensity within the given diagram does not correspond to the standard value (at least 0.04 l/(s*m2) is required). In order to establish whether this sprinkler design meets the requirements of GOST R 51043-94 and NPB 87- 2000 on an area of ​​12 m2 (radius ~2 m), appropriate tests are required.

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

According to the given irrigation diagrams for a given sprinkler design, appropriate conclusions can be drawn about the effect of pressure on irrigation intensity.

For example, if the RPTK sprinkler is installed with the rosette facing up, then at an installation height of 2.5 m, the irrigation intensity is practically independent of pressure. Within the area of ​​the zone with radii 1.5; 2 and 2.5 m, the irrigation intensity with a 2-fold increase in pressure increases by 0.005 l/(s*m2), i.e. by 4.3-6.7%, which indicates a significant increase in the irrigation area. If, with a 2-fold increase in pressure, the irrigation area remains unchanged, then the irrigation intensity should increase by 1.41 times.

When installing the RPTC sprinkler with the rosette 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 have increased by 41%).