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 the loss of tightness occurs due to the spontaneous destruction of a heat-sensitive shut-off 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 always be under sufficient 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 sprinkler manufacturers 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 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 for a number of tests that make it possible to guarantee 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, an aqueous solution of 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 launch control may be affected for some time high temperature. 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 verify resistance to climatic influences, 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 sprinklers in the lower 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 a glass flask is used as a thermal lock, its integrity must be checked 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 castle

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 of the 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 fire hazard:

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 should be noted positive points 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 storage facilities, 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 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 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: than bigger 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 fire 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 mathematical formula, and to create such a two-dimensional data set 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 required irrigation intensity apply to the simultaneous operation of 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
Outlet diameter, mm	Water flow through the sprinkler, l/min	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:

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.
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

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.
Significant differences between sprinklers are contained in the requirements of various 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.
The advantage of the “one sprinkler protection” method is the higher probability that the fire will be extinguished by one sprinkler.
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. 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. System fire protection. 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 installations fire extinguishing L.M Meshman, S.G. Tsarichenko, V.A. Bylinkin, V.V. Aleshin, R.Yu. Gubin; Under general edition N.P. Kopylova. – M.: VNIIPO EMERCOM of the Russian Federation, 2002.

Discussed many times, you say? And, like, is everything clear? What thoughts would you have on this little study:
The main contradiction, currently unresolved by the standards, is between the circular sprinkler irrigation map (diagram) and the square (overwhelming majority) arrangement of sprinklers on the protected area (calculated according to SP5).
1. For example, we need to extinguish 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 a certified area of 12 m2 the intensity (according to the sprinkler passport) i = 0.215 l/s*m2 will be ensured. Since the passport contains a reference to the fact that this sprinkler meets the requirements of GOST R 51043-2002, then, according to clause 8.23 (checking the intensity and protected area), we must consider these 12 m2 (according to the passport - protected area) as the area of a circle with a radius R= 1.95 m. By the way, 0.215 * 12 = 2.58 (l/s) will flow onto such an area, which is only 2.58/4.22 = 0.61 of the total sprinkler flow rate, i.e. Almost 40% of the supplied water flows beyond the regulatory protected area.
SP5 (Tables 5.1 and 5.2) requires that the standard intensity be ensured in the regulated protected area (and there, as a rule, at least 10 sprinklers are located in a square-cluster manner), while according to paragraph B.3.2 of SP5:
- conditional calculated area protected by one sprinkler: Ω = L2, here L is the distance between sprinklers (i.e. the side of the square in the corners of which sprinklers are located).
And, understanding wisely that all the water pouring out of the sprinkler will remain on the protected area when our sprinklers are located at the corners of conventional squares, we very simply calculate the intensity that the AUP provides on the standard protected area: the entire flow (and not 61%) through the dictating sprinkler (through the others the flow rate will be greater by definition) is divided by the area of the 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, 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 standard protected area will be 4.22/12 = 0.35 l/s*m2 - all the water will pour onto the fire!
Those. to protect the area, we can reduce the consumption by 0.35/0.215 = 1.63 times (ultimately - construction costs), and obtain the intensity required by the standards, we don’t need 0.35 l/s*m2, 0.215 is enough l/s*m2. And for the entire standard area of 120 m2 we will need (simplified) calculated 0.215 (l/s*m2)*120(m2)=25.8 (l/s).
But here, ahead of the rest of the planet, comes out the one developed and introduced in 1994. Technical Committee TC 274 “ Fire safety” GOST R 50680-94, namely this point:
7.21 Irrigation intensity is determined in the selected area when one sprinkler is operating for sprinklers ... sprinklers at the design pressure. - (in this case, the sprinkler irrigation map using the intensity measurement method adopted in this GOST is a circle).
This is where we arrived, because, literally understanding clause 7.21 of GOST R 50680-94 (we extinguish in one piece) in conjunction with clause B.3.2 SP5 (we protect 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 sprinkler passport this (round!) protected area is specified, and beyond the boundaries of this circle the intensity will be 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. In this case, when extinguishing on a standard area (with several sprinklers operating), the actual irrigation intensity will be 4.22/7.6 = 0.56 (l/s*m2). And in this case, for the entire standard area we will need 0.56 (l/s*m2)*120(m2)=67.2 (l/s). This is 67.2 (l/s) / 25.8 (l/s) = 2.6 times more than when calculated using 4 sprinklers (per square)! How much does this increase the costs of pipes, pumps, tanks, etc.?

FEDERAL STATE BUDGET EDUCATIONAL INSTITUTION OF HIGHER PROFESSIONAL EDUCATION

"CHUVASH STATE PEDAGOGICAL UNIVERSITY

them. AND I. YAKOVLEV"

Department of 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.

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 irrigators comes from abroad, since Russian manufacturers PO "Spets-Avtomatika" (Biysk) and CJSC "Ropotek" (Moscow) are not able to fully meet the needs of domestic consumers.

In prospectuses for foreign irrigators, as a rule, there is no data on most technical parameters regulated by domestic standards. In this regard, carry out comparative assessment 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, the irrigation diagrams of a universal sprinkler type CU/P, installed with the socket facing up, change almost slightly depending on the supply pressure within 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 it satisfies this design sprinkler requirements of GOST R 51043-94 and NPB 87-2000 on an area of 12 m 2 (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%).