Choice automatic installation fire fighting
The type of automatic extinguishing installation, the method of extinguishing, the type of fire extinguishing agents, the type of equipment for fire automatic fire installations are determined by the design organization depending on the technological, structural and space-planning features of the protected buildings and premises, taking into account the requirements of Appendix A “List of buildings, structures, premises and equipment , subject to protection by automatic fire extinguishing installations and automatic fire alarms" (SP 5.13130.2009).
Thus, as a designer in carpentry shop We install a water fire extinguishing sprinkler system. Depending on the air temperature in the warehouse of electrical goods in combustible packaging, we accept a water-filled fire extinguishing sprinkler system, since the air temperature in the carpentry shop is more than + 5 ° C (clause 5.2.1. SP 5.13130.2009).
The fire extinguishing agent in a water fire extinguishing sprinkler installation will be water (handbook by A.N. Baratov).
Hydraulic calculation of a water sprinkler fire extinguishing installation
4.1 Selection of standard data for calculation and choice of sprinklers
Hydraulic calculations are carried out taking into account the operation of all sprinklers on a minimum sprinkler AUP area of at least 90 m2 (Table 5.1 (SP 5.13130.2009)).
We determine the required water flow through the dictating sprinkler:
where is the standard irrigation intensity (Table 5.2 (SP 5.13130.2009));
Design area for sprinkler irrigation, .
1. The estimated water flow through the dictating sprinkler located in the dictating protected irrigated area is determined by the formula:
where K is the sprinkler productivity coefficient, taken according to technical documentation on the product, ;
P - pressure in front of the sprinkler, .
As a designer, we select a water sprinkler model ESFR d=20 mm.
We determine the water flow through the dictating sprinkler:
Checking the condition:
the condition is met.
We determine the number of sprinklers involved in the hydraulic calculation:
where is the AUP consumption, ;
Consumption of 1 sprinkler, .
4.2 Placement of sprinklers in the plan of the protected room
4.3 Pipeline routing
1. The diameter of the pipeline in section L1-2 is assigned by the designer or determined by the formula:
Consumption in this area, ;
Speed of water movement in the pipeline, .
4.4 Hydraulic network calculation
According to Table B.2 of Appendix B “Methodology for calculating AUP parameters for surface fire extinguishing with water and low expansion foam” (SP 5.13130.2009), we take the nominal diameter of the pipeline equal to 50 mm; for steel water and gas pipes (GOST - 3262 - 75) the specific characteristic of the pipeline is equal to .
1. Pressure loss P1-2 in section L1-2 is determined by the formula:
where is the total consumption of waste water of the first and second sprinkler, ;
Length of the section between 1 and 2 sprinklers, ;
Specific characteristics of the pipeline, .
2. The pressure at sprinkler 2 is determined by the formula:
3. The flow rate of sprinkler 2 will be:
8. Pipeline diameter at the site L 2-a will be:
accept 50 mm
9. Pressure loss R 2-a Location on L 2-a will be:
10. Point pressure A will be:
11. Estimated flow rate in the area between 2 and point A will be equal to:
12. For the left branch of row I (Figure 1, section A) it is required to provide flow at pressure. The right branch of the row is symmetrical to the left, so the flow rate for this branch will also be equal, and therefore the pressure at the point A will be equal.
13. Water consumption for branch I will be:
14. Calculate the branch coefficient using the formula:
15. Pipeline diameter at the site L a-c will be:
we accept 90 mm, .
16. The generalized characteristic of branch I is determined from the expression:
17. Pressure loss R a-c Location on L a-c will be:
18. The pressure at point b will be:
19. Water flow from branch II is determined by the formula:
20. Water flow from branch III is determined by the formula:
we accept 90 mm, .
21. Water flow from branch IV is determined by the formula:
we accept 90 mm, .
22. Calculate the row coefficient using the formula:
23. Let's calculate the consumption using the formula:
24. Checking the condition:
the condition is met.
25. The required pressure of the fire pump is determined by the formula:
where is the required pressure of the fire pump, ;
Pressure loss in horizontal sections of the pipeline;
Pressure loss on a horizontal section of the pipeline s - st, ;
Pressure loss in the vertical section of the pipeline DB, ;
Pressure losses in local resistances (shaped parts B And D), ;
Local resistances in the control unit (signal valve, gate valves, shutters), ;
Pressure at the dictating sprinkler, ;
Piezometric pressure (geometric height of the dictating sprinkler above the axis of the fire pump), ;
Fire pump inlet pressure, ;
Pressure required, .
26. Pressure loss on a horizontal section of the pipeline s - st will be:
27. Pressure loss on a horizontal section of the pipeline AB will be:
where is the distance to the fire extinguishing pumping station, ;
28. The pressure loss on the horizontal section of the BD pipeline will be:
29. Pressure losses in horizontal sections of the pipeline will be:
30. Local resistance in the control unit will be:
31. Local resistance in the control unit (signal valve, valves, shutters) is determined by the formula:
where is the pressure loss coefficient, respectively, in the sprinkler control unit (accepted individually according to the technical documentation for the control unit as a whole);
Water flow through the control unit, .
32. Local resistance in the control unit will be:
We select an air sprinkler control unit - УУ-С100/1.2Вз-ВФ.О4-01 TU4892-080-00226827-2006* with a pressure loss coefficient of 0.004.
33. The required pressure of the fire pump will be:
34. The required pressure of the fire pump will be:
35. Checking the condition:
the condition is not met, i.e. installation of an additional tank is required.
36. According to the obtained data, we select a pump for the AUPT - a 1D centrifugal pump, series 1D250-125, with an electric motor power of 152 kW.
37. Determine the water supply in the tank:
where Q us is the pump flow rate, l/s;
Q water network - water supply network consumption, l/s;
Calculation of automatic water feeder
Minimum pressure in automatic water feeder:
N av = N 1 + Z + 15
where H 1 is the pressure at the dictating sprinkler, m.v.s.;
Z-geometric height from the pump axis to the sprinkler level, m;
Z= 6m (room height) + 2 m (pump room floor level below) = 8m;
15 - reserve for operation of the installation before turning on the backup pump.
N av =25+8+15=48 m.v.s.
To maintain the pressure of the automatic water feeder, we select a CR 5-10 jockey pump with a pressure of 49.8 m.w.s.
Ministry of Education and Science of the Russian Federation
Ufa State Aviation Technical University
Department of Fire Safety
Calculation and graphic work
Topic: Calculation of automatic water fire extinguishing installation
Supervisor:
department assistant
“Fire Safety” Gardanova E.V.
Executor
student of group PB-205 vv
Gafurova R.D.
Gradebook No. 210149
Ufa, 2012
Exercise
In this work, it is necessary to make an axonometric diagram of a water automatic fire extinguishing system, indicating on it the sizes and diameters of pipe sections, locations of sprinklers and the necessary equipment.
Carry out hydraulic calculations for selected pipeline diameters. Determine the design flow rate of an automatic water fire extinguishing installation.
Calculate the pressure that should be provided pumping station and select equipment for the pumping station.
fire extinguishing installation pipeline pressure
annotation
The RGR course “Industrial and fire automatics” is aimed at solving specific problems in the installation and maintenance of fire automatics installations.
This paper shows ways to apply theoretical knowledge to solve engineering problems related to the creation of fire protection systems for buildings.
During the work:
technical and regulatory documentation regulating the design, installation and operation of fire extinguishing installations was studied;
the method of technological calculations to ensure the required parameters of the fire extinguishing installation is presented;
shows the rules for using technical literature and regulatory documents on the creation of fire protection systems.
Carrying out RGR contributes to the development of students’ skills independent work and the formation of a creative approach to solving engineering problems regarding the creation of fire protection systems for buildings.
annotation
Introduction
Initial data
Calculation formulas
Basic operating principles of a fire extinguishing installation
1 Operating principle of the pumping station
2 Operating principle of a sprinkler system
Design of a water fire extinguishing installation. Hydraulic calculation
Equipment selection
Conclusion
Bibliography
Introduction
Automatic water fire extinguishing systems are currently the most widespread. They are used over large areas to protect shopping and multifunctional centers, administrative buildings, sports complexes, hotels, businesses, garages and parking lots, banks, energy facilities, military and special-purpose facilities, warehouses, residential buildings and cottages.
My version of the task presents a facility for the production of alcohols, ethers and utility rooms, which, in accordance with clause 20 of table A.1 of appendix A of the set of rules 5.13130.2009, regardless of area, must have automatic system fire extinguishing It is not necessary to equip the remaining utility rooms of the facility in accordance with the requirements of this table with an automatic fire extinguishing system. The walls and ceilings are reinforced concrete.
The main types of fire loads are alcohols and ethers. In accordance with the table, we decide that it is possible to use a foaming agent solution for extinguishing.
The main fire load in a facility with a room height of 4 meters comes from the repair area, which, in accordance with the table in Appendix B of the set of rules 5.13130.2009, belongs to group 4.2 of premises according to the degree of fire hazard, depending on their functional purpose and the fire load of combustible materials.
The facility does not have premises of categories A and B for explosion and fire hazards in accordance with SP 5.13130.2009 and explosive zones in accordance with the PUE.
To extinguish possible fires in the facility, taking into account the existing flammable load, it is possible to use a foaming agent solution.
To equip a facility for the production of alcohols and ethers, we will choose an automatic sprinkler-type foam fire extinguishing installation filled with a foaming agent solution. Foaming agents mean concentrated aqueous solutions of surfactants (surfactants) intended to produce special solutions of wetting agents or foam. The use of such foaming agents during fire extinguishing can significantly reduce the intensity of combustion within 1.5-2 minutes. The methods of influencing the source of ignition depend on the type of foaming agent used in the fire extinguisher, but the basic principles of operation are the same for all:
due to the fact that the foam has a mass significantly less than the mass of any flammable liquid, it covers the surface of the fuel, thereby suppressing the fire;
the use of water, which is part of the foaming agent, allows, within a few seconds, to reduce the temperature of the fuel to a level at which combustion becomes impossible;
the foam effectively prevents the hot fumes generated by the fire from spreading further, making re-ignition virtually impossible.
Thanks to these features, foam concentrates are actively used for fire extinguishing in the petrochemical and chemical industries, where there is a high risk of ignition of flammable and flammable liquids. These substances do not pose a threat to human health or life, and traces of them can be easily removed from premises.
1. Initial data
Hydraulic calculations are carried out in accordance with the requirements of SP 5.13130.2009 “Fire extinguishing and alarm installations. Design standards and rules" according to the methodology outlined in Appendix B.
The protected object is a room volume of 30x48x4m, in plan - a rectangle. The total area of the facility is 1440 m2.
We find the initial data for the production of alcohols and ethers in accordance with a certain group of premises from Table 5.1 of this set of rules in the section “Water and foam fire extinguishing installations”:
irrigation intensity - 0.17 l/(s*m2);
area for calculating water consumption - 180 m2;
minimum water consumption of fire extinguishing installation - 65 l/s;
the maximum distance between sprinklers is 3 m;
The selected maximum area controlled by one sprinkler is 12m2.
operating time - 60 min.
To protect the warehouse, we select the sprinkler SPO0-RUo(d)0.74-R1/2/P57(68,79,93,141,182).V3-"SPU-15" PO "SPETSAVTOMATIKA" with a performance coefficient k = 0.74 (according to technical .documentation for the sprinkler).
2. Calculation formulas
The estimated water flow through the dictating sprinkler located in the dictating protected irrigated area is determined by the formula
where q1 is the consumption of waste water through the dictating sprinkler, l/s; is the sprinkler performance coefficient accepted according to the technical documentation for the product, l/(s MPa0.5);
P - pressure in front of the sprinkler, MPa.
The flow rate of the first dictating sprinkler is the calculated value of Q1-2 in the section L1-2 between the first and second sprinklers
The diameter of the pipeline in section L1-2 is assigned by the designer or determined by the formula
where d1-2 is the diameter between the first and second sprinklers of the pipeline, mm; -2 is the waste water consumption, l/s;
μ - flow coefficient; - water movement speed, m/s (should not exceed 10 m/s).
The diameter is increased to the nearest nominal value according to GOST 28338.
Pressure loss P1-2 in section L1-2 is determined by the formula
where Q1-2 is the total flow rate of the first and second sprinklers, l/s; t is the specific characteristic of the pipeline, l6/s2;
A is the specific resistance of the pipeline, depending on the diameter and roughness of the walls, c2/l6.
The resistivity and specific hydraulic characteristics of pipelines for pipes (made of carbon materials) of various diameters are given in table B.1<#"606542.files/image005.gif">
The hydraulic characteristics of the rows, made structurally identical, are determined by the generalized characteristics of the design section of the pipeline.
The generalized characteristic of row I is determined from the expression
Pressure loss per section a-b for symmetrical and asymmetrical circuits we find using the formula.
The pressure at point b will be
Рb=Pa+Pa-b.
Water consumption from row II is determined by the formula
The calculation of all subsequent rows until the calculated (actual) water flow rate and the corresponding pressure are obtained is similar to the calculation of row II.
We calculate symmetrical and asymmetrical ring circuits in the same way as a dead-end network, but at 50% of the calculated water flow for each half-ring.
3. Basic principles of operation of a fire extinguishing installation
An automatic fire extinguishing installation consists of the following main elements: an automatic fire extinguishing pumping station with a system of inlet (suction) and supply (pressure) pipelines; - control units with a system of supply and distribution pipelines with sprinklers installed on them.
1 Operating principle of the pumping station
In standby mode, the supply and distribution pipelines of sprinkler systems are constantly filled with water and are under pressure, ensuring constant readiness to extinguish a fire. The jockey pump turns on when the pressure alarm is activated.
In the event of a fire, when the pressure on the jockey pump (in the supply pipeline) drops, when the pressure alarm is triggered, the working fire pump is turned on, providing full flow. At the same time, when the fire pump is turned on, a fire alarm signal is sent to the fire safety system of the facility.
If the electric motor of the working fire pump does not turn on or the pump does not provide the design pressure, then after 10 s the electric motor of the backup fire pump turns on. The impulse to turn on the backup pump is supplied from a pressure alarm installed on the pressure pipeline of the working pump.
When the working fire pump is turned on, the jockey pump is automatically turned off. After the fire has been eliminated, the water supply to the system is stopped manually, for which the fire pumps are turned off and the valve in front of the control unit is closed.
3.2 Operating principle of the sprinkler system
If a fire occurs in the room protected by the sprinkler section and the air temperature rises above 68 "C, the thermal lock (glass bulb) of the sprinkler is destroyed. Water, which is under pressure in the distribution pipelines, pushes out the valve that blocks the outlet of the sprinkler, and it opens. Water from the sprinkler enters the room; the pressure in the network drops. When the pressure drops by 0.1 MPa, pressure alarms installed on the pressure pipeline are triggered, and a pulse is sent to turn on the working pump.
The pump takes water from the city water supply network, bypassing water metering unit, and supplies it to the piping system of the fire extinguishing installation. In this case, the jockey pump is automatically switched off. When a fire occurs on one of the floors, liquid flow detectors duplicate signals about the activation of the water fire extinguishing installation (thereby identifying the location of the fire) and simultaneously turn off the power supply system of the corresponding floor.
Simultaneously with the automatic activation of the fire extinguishing installation, signals about a fire, the activation of pumps and the start of operation of the installation in the appropriate direction are transmitted to the premises of the fire post with round-the-clock presence of operational personnel. In this case, the light alarm is accompanied by an audible alarm.
4. Design of a water fire extinguishing installation. Hydraulic calculation
Hydraulic calculations are carried out for the most remote and highly located (“dictating”) sprinkler under the condition that all sprinklers that are furthest from the water feeder and mounted on the design area are activated.
We outline the routing of the pipeline network and the layout plan for sprinklers and select the dictating protected irrigated area on the hydraulic plan diagram of the AUP, on which the dictating sprinkler is located, and carry out a hydraulic calculation of the AUP.
Determination of the estimated water flow over the protected area.
The determination of flow and pressure in front of the “dictating sprinkler” (flow at point 1 on the diagram in Appendix 1) is determined by the formula:
=k √ H
The flow rate of the “dictating” sprinkler must ensure the standard irrigation intensity, therefore:
min = I*S=0.17 * 12 = 2.04 l/s, thus Q1 ≥ 2.04 l/s
Note. When calculating, it is necessary to take into account the number of sprinklers protecting the calculated area. On a calculated area of 180 m2 there are 4 rows of 5 and 4 sprinklers, the total flow rate must be at least 60 l/s (see Table 5.2 SP 5.13130.2009 for 4.2 group of premises). Thus, when calculating the pressure in front of the “dictating” sprinkler, it is necessary to take into account that in order to ensure the minimum required flow rate of the fire extinguishing installation, the flow rate (and therefore the pressure) of each sprinkler will have to be increased. That is, in our case, if the flow rate from the sprinkler is taken equal to 2.04 l/s, then the total flow rate of 18 sprinklers will be approximately equal to 2.04 * 18 = 37 l/s, and taking into account the different pressure in front of the sprinklers it will be slightly more, but this value does not correspond to the required flow rate of 65 l/s. Thus, it is necessary to select the pressure in front of the sprinkler so that the total flow rate of 18 sprinklers located on the design area is more than 65 l/s. For this: 65/18=3.611, i.e. the flow rate of the dictating sprinkler should be more than 3.6 l/s. Having carried out several variants of calculations in the draft, we determine the required pressure in front of the “dictating” sprinkler. In our case, H=24 m.v.s.=0.024 MPa.
(1) =k √ H= 0.74√24= 3.625 l/s;
Let's calculate the diameter of the pipeline in a row using the following formula:
From where we get, at a water flow speed of 5 m/s, the value d = 40 mm and take the value of 50 mm for the reserve.
Pressure loss in section 1-2: dH(1-2)= Q(1) *Q(1) *l(1-2) / Km= 3.625*3.625*6/110=0.717 m.w.s.= 0.007MPa;
To determine the flow rate from the 2nd sprinkler, we calculate the pressure in front of the 2nd sprinkler:
H(2)=H(1)+ dH(1-2)=24+0.717=24.717 m.v.s.
Flow from the 2nd sprinkler: Q(2) =k √ H= 0.74√24.717= 3.679 l/s;
Pressure loss in section 2-3: dH(2-3)= (Q(1) + Q(2))*(Q(1) + Q(2))*l(2-3) / Km= 7.304* 7.304*1.5/110=0.727 m.v. With;
Pressure at point 3: Н(3)=Н(2)+ dH(2-3)= 24.717+0.727=25.444 m.v.s;
The total flow rate of the right branch of the first row is Q1 + Q2 = 7.304 l/s.
Since the right and left branches of the first row are structurally identical (2 sprinklers each), the flow rate of the left branch will also be equal to 7.304 l/s. The total flow rate of the first row is Q I = 14.608 l/s.
The flow rate in point 3 is divided in half, since the supply pipeline is made as a dead end. Therefore, when calculating pressure losses in section 4-5, the flow rate of the first row will be taken into account. Q(3-4) = 14.608 l/s.
We will accept the value d=150 mm for the main pipeline.
Pressure loss in section 3-4:
(3-4)=Q(3)*Q(3)*l(3-4)/Km= 14.608 *14.608 *3/36920=0.017 m.v. With;
Pressure at point 4: Н(4)=Н(3)+ dH(3-4)= 25.444+0.017=25.461 m.v. With;
To determine the flow rate of the 2nd row, it is necessary to determine coefficient B:
That is, B= Q(3)*Q(3)/H(3)=8.39
Thus, the consumption of the 2nd row is equal to:
II= √8, 39*24.918= 14.616 l/s;
Total flow rate from 2 rows: QI +QII = 14.608+14.616 =29.224 l/s;
Similarly, I find (4-5)=Q(4)*Q(4)*l(4-5)/Km= 29.224 *29.224*3/36920=0.069 m.v. With;
Pressure at point 5: Н(5)=Н(4)+ dH(4-5)= 25.461+0.069=25.53 m. With;
Since the next 2 rows are asymmetrical, we find the consumption of the 3rd row as follows:
That is, B= Q(1)*Q(1)/H(4)= 3.625*3.625/25.461=0.516lev= √0.516 * 25.53= 3.629 l/s;(5)= 14.616 +3.629 =18.245 l /s= Q(5)*Q(5)/H(5)=13.04III= √13.04 * 25.53= 18.24 l/s;
Total flow rate from 3 rows: Q (3 rows) = 47.464 l/s;
Pressure loss in section 5-6:(5-6)=Q (6) *Q (6) *l(5-6)/Km= 47.464 *47.464 *3/36920=0.183 m.v. With;
Pressure at point 6: Н(6)=Н(5)+ dH(5-6)= 25.53+0.183=25.713 m. With;
IV= √13.04 * 25.713= 18.311 l/s;
Total flow rate from 4 rows: Q(4 rows) =65.775 l/s;
Thus, the calculated flow rate is 65.775 l/s, which meets the requirements of regulatory documents >65 l/s.
The required pressure at the beginning of the installation (near the fire pump) is calculated from the following components:
pressure in front of the “dictating” sprinkler;
pressure loss in the distribution pipeline;
pressure loss in the supply pipeline;
pressure loss in the control unit;
difference in elevation between the pump and the “dictating” sprinkler.
Pressure loss in the control unit:
.water.st.,
The required pressure that the pumping unit must provide is determined by the formula:
tr=24+4+8.45+(9.622)*0.2+9.622 =47.99 m.v.s.=0.48 MPa
Total water consumption for sprinkler fire extinguishing: (4 rows) = 65.775 l/s = 236.79 m3/h
Required pressure:
tr = 48 m.v.s. = 0.48 MPa
5. Equipment selection
Calculations were carried out taking into account the selected sprinkler SPOO-RUoO,74-R1/2/R57.VZ-“SPU-15”-bronze with an outlet diameter of 15 mm.
Taking into account the specifics of the facility (a unique multifunctional building with a large number of people), the complex pipeline system of the internal fire-fighting water supply system, the pumping unit is selected with a supply pressure reserve.
The extinguishing time is 60 minutes, which means that 234,000 liters of water must be supplied.
The design solution selected is the Irtysh-TsMK pump 150/400-55/4 speed 1500 rpm, which has a reserve of both H = 48 m.v.s. and Q. of the pump = 65 m.
The operating characteristics of the pump are shown in the figure.
Conclusion
This RGR presents the results of the studied methods for designing automatic fire extinguishing installations, and the calculations necessary for designing an automatic fire extinguishing installation.
Based on the results of hydraulic calculations, the placement of sprinklers was determined in order to achieve a water flow rate for fire extinguishing in the protected area of 65 l/s. To ensure the standard intensity of irrigation, a pressure of 48 m.w.c. will be required.
The equipment for the installations was selected based on the standard minimum irrigation intensity, calculated flow rates and required pressure.
Bibliography
1 SP 5.13130.2009. Fire alarm and fire extinguishing installations are automatic. Design norms and rules.
Federal Law No. 123 - Federal Law “Technical Regulations on Fire Safety Requirements” dated July 22, 2008
Design of water and foam automatic fire extinguishing installations / L.M. Meshman, S.G. Tsarichenko, V.A. Bylinkin, V.V. Aleshin, R.Yu. Gubin; edited by N.P. Kopylova. - M: VNIIPO EMERCOM of the Russian Federation, 2002.-413 p.
Websites of manufacturers of fire-fighting equipment
Hydraulic calculation of a sprinkler or deluge network is aimed at:
Determination of water flow, i.e. irrigation intensity or specific flow rate for “dictating” sprinklers (the most remote or highly located);
Comparison of specific consumption (irrigation intensity) with the required (standard), as well as determination of the required pressure (pressure) of water feeders and the most economical pipe diameters.
A detailed methodology for calculating the hydraulic networks of sprinkler and deluge fire extinguishing installations with water and aqueous solutions, aggregate AFS with finely sprayed water, AFS with forced start and sprinkler and deluge AFS is given in Appendix B. The critical stage of the hydraulic calculation is the choice of sprinkler and determination of the pressure that must be provided at the " dictating" sprinkler.
When determining the parameters of the sprinkler, it is necessary to take into account some specifications, which are:
Fire extinguishing agent consumption;
Irrigation intensity;
The maximum irrigation area within which the required intensity is ensured, the distance between sprinklers.
Sprinkler consumption Q (dm3/s) is determined by the formula:
where K is the performance coefficient,
P - pressure in front of the sprinkler, MPa.
The most important parameter is the performance coefficient, that is, the ability of the sprinkler to pass a certain amount of water through itself, in turn, depends on the size of the outlet hole of the sprinkler: the larger the hole, the greater the coefficient.
To calculate the flow rate Q, you need to determine the required pressure P at the sprinkler at a given irrigation intensity.
One of the ways to determine the required pressure of a sprinkler is to determine the pressure according to the graph of the dependence of the irrigation intensity of sprinklers on pressure (Fig. 4.1), given in the technical documentation. According to the schedule, according to a certain intensity and the selected nominal diameter of the sprinkler, the required minimum pressure is determined.
As can be seen from the graph, for an irrigation intensity of 0.12 dm 3 / m 2, three types of sprinkler are suitable - “SVN-K115”, “SVN-K80” and “SVN-K57”. Select a sprinkler that provides the specified intensity at lower pressure, in our case it is “SVN-K115” according to the passport CBO0-PHo(d)0.59-R1/2/P57.B3 - (outlet diameter 15mm, performance coefficient K = 0.59). When choosing a sprinkler, it is also necessary to take into account that the minimum pressure for most sprinklers, at which the functionality of the sprinkler is ensured, according to the passport data, is 0.1 MPa.
The SVN-K115 sprinkler provides an irrigation intensity of 0.12 dm 3 / m 2 at a pressure of 0.17 MPa (Fig. 4.1).
Rice. 4.1. Graph of dependence of irrigation intensity of sprinklers on pressure.
According to the calculation of the installation flow rate, it is determined from the condition of simultaneous operation of all sprinklers mounted on the protected dictating area, determined according to Table 5.1-5.3, taking into account the fact that the flow rate of sprinklers installed along the distribution pipes increases with distance from the “dictating” sprinkler. In this case, the total protected area can be many times larger, and the number of sprinklers can reach 800 or 1200 when using liquid flow indicators.
The placement of sprinklers is carried out taking into account the maximum distance, the water flow is calculated within the protected dictating area established in Table 5.1. The calculation of the distribution network of the sprinkler AUP is checked based on the condition that such a number of sprinklers are activated, the total consumption of which on the accepted protected irrigated area will be no less than the standard values for the consumption of fire extinguishing agent given in Tables 5.1-5.3. If in this case the flow rate is less than that indicated in Tables 5.1-5.3, then the calculation must be repeated with an increase in the number of sprinklers and the diameters of the distribution network pipelines. Recalculation of the network may be repeated many times.
The authors of the manual, for simplification, when performing hydraulic calculations for educational purposes, propose to determine the number of sprinklers to protect the minimum dictating area and their placement according to the formula:
Where q 1 — consumption of waste water through the dictating sprinkler, l/s;
Q n - standard flow rate of sprinkler AUP according to tables 5.1-5.3 SP-5.13130.2009
As a result of this assumption, the final calculated flow rate will exceed the standard by 10-15%, but the calculation itself is significantly simplified.
As an example, we will arrange the sprinklers of an automatic water fire extinguishing installation for a textile enterprise with the installation parameters:
Water irrigation intensity - 0.12 l/(s*m2);
Fire extinguishing agent consumption - at least 30 l/s;
The minimum irrigation area is at least 120 m2;
The maximum distance between sprinklers is no more than 4 m;
The minimum pressure that must be provided at the dictating sprinkler is P = 0.17 MPa (Fig. 4.1.);
The estimated water flow through the dictating sprinkler located in the dictating protected irrigated area is determined by the formula:
K— sprinkler performance coefficient, accepted according to the technical documentation for the product, l/(s MPa 0.5);
The minimum estimated number of sprinklers required to protect the dictating area:
Where Q n = 30 l/s - standard flow rate of sprinkler AUP according to tables 5.1.
The arrangement of sprinklers on the allocated minimum dictating area is shown in Fig. 4.2. When arranging, it is necessary to take into account that the distance between sprinklers should not exceed the standard distances indicated in Tables 5.1.
Rice. 4.2 Sprinkler layout
Further calculation of the installation involves determining:
Pipeline diameters;
Pressure at nodal points;
Pressure loss in pipelines, control unit and shut-off valves;
Flow rates on subsequent sprinklers from the dictating one within the protected area;
Determination of the total design flow rate of the installation.
For clarity, the routing of the pipeline network through the protection object is depicted in axonometric form (Fig. 4.3).
Fig. 4.3 Axonometric view of a water fire extinguishing sprinkler installation using a symmetrical dead-end design
The layout of sprinklers on the distribution pipeline of the AUP can according to a dead-end or ring pattern, symmetrical or asymmetrical. In Fig. 4.3 shows a water fire extinguishing sprinkler installation using a symmetrical dead-end circuit, in Fig. 4.4. according to a ring asymmetrical scheme.
Fig. 4.4 Axonometric view of a water fire extinguishing sprinkler installation using an asymmetrical ring pattern
The diameter of the pipelines can be assigned by the designer or calculated using the formula:
Where d— diameter of the pipeline section being determined, mm;
Q— flow rate in the determined section of the pipeline, l/s;
v- the speed of water movement should be no more than 10 m/s, and in suction - no more than 2.8 m/s;
The pressure loss on the pipeline section is determined by the formula:
Where L- the length of the pipeline section in which pressure losses are calculated;
TO T — The specific characteristics of the pipeline are determined according to Table B.2 of Appendix B.
After determining the pressure at point a (Fig. 4.3) and the total flow rate of the first row sprinklers, the generalized characteristic of the first row is determined using the formula:
Since the second and third rows are identical to the first, after calculating the pressure loss between the first and second rows, the generalized characteristic is used to determine the flow rate of the second row. The consumption of the third row is calculated similarly.
Fire pump pressure, according to the diagram shown in Fig. 4.3, consists of the following components:
Where R e— required fire pump pressure, MPa;
R v-g— pressure loss on the horizontal section of the pipeline, MPa;
R g-d— pressure loss in the vertical section of the pipeline, MPa;
R M— pressure loss in local resistances (shaped parts), MPa;
R uu— local resistance in the control unit (signal valve, valves, shutters), MPa;
R in— pressure at the dictating protected area, MPa;
Z— piezometric pressure (geometric height of the dictating sprinkler above the axis of the fire pump), MPa; Z = N/100;
P VX — pressure at the inlet of the fire pump (determined according to the option), MPa.
- This list contains a completely comprehensive list of possibilities applicable to most calculations. Let's take a closer look at the program. Interface and program operation
The program interface does not cause any particular complaints. All elements are quite clearly located and perform their functions. Mastering it does not require any time investment for any person who is more or less accustomed to working in the WINDOWS environment. The interface is built on tabs, which you can switch between at any time to make changes. In the first tab, general project data is entered, which is then used to generate the report. The main working window (or windows, depending on the number) is the section window. There, the initial data is entered in tabular form, as well as intermediate calculations for flow rates and pressure.
I won’t bore you with a description of the procedure for entering parameters, especially since all this is explained in detail in video tutorials that can be called up by pressing Ctrl + F1 (provided you have an Internet connection). I will only note that entering parameters is quite simple, if you have an axonometric diagram, or at least a section plan (for preliminary calculation) with printed dimensions. In addition to the supply and distribution pipelines, the calculation can take into account deluge curtains, as well as fire hydrants of the combined fire-fighting water supply system. One of the disadvantages of the program is the lack of a graphical component that would allow visual control of the input of parameters of the fire extinguishing section. I find this function extremely useful, and including a short axonometry in the report would make it very visual. An example of such a function can currently only be seen in foreign software. 
An excellent feature included in the program is the ability to automatically enter hydraulic parameters of equipment (sprinklers, fire hydrants and diaphragms, control units and flexible hoses from corrugated pipe) when selecting it from the built-in catalog. After completing the calculation of the dictating section (before the control unit), on the “Selection of pumps” tab, parameters are entered and calculated pumping equipment fire extinguishing 
Options for hydraulic circuits for switching on fire pumps include up to 5 pumps (main and backup), connected both in parallel and in series. Using the “Additional/Calculations” tab, the number of pipes for connection is automatically calculated fire equipment, tank volume and minimum required diameter of the supply pipeline. Report The result of the program is a report in PDF format. Section calculations included in the report can be selected. Price The cost of the HydRaVPT software can be calculated based on the time of use:- 1 month – 2,500 rubles;
- 4 months – 6,000 rubles;
- 12 months – 12,000 rubles;
- without time limit – 25,000 rubles.
- When you purchase a program with unlimited use, you receive free support and updates forever.
- The software protection allows it to be used on different computers, since the key file is located on a flash drive. Thus, there is no need to purchase several copies of the program for the company. One license is purchased, and a flash drive with a key is transferred between employees if necessary.
- practically the first and only program of its kind;
- availability of a certificate of conformity, which makes it possible to include program reports as part of the project documentation;
- clear and convenient interface;
- Video tutorials are a great help when learning how to use the program;
- the presence of additional accompanying calculations - tank volume, number of pipes for fire fighting equipment, diameter of the suction pipeline;
- good support through the website GidraVPT.rf;
- reasonable price (10-20% of the cost design work one object at a time).
- lack of a graphical component in the program.
Why doesn't water extinguish?
An expert review of errors made when carrying out hydraulic calculations of an automatic water fire extinguishing installation (AWF).
As often happens when trying to optimize during design, many “specialists” end up with a very ineffective water fire extinguishing installation.
This article outlines some of the author’s observations about the intricacies of the hydraulic calculation of water fire extinguishing installations and mistakes that must be avoided when conducting its examination. A partial analysis of the existing official calculation methodology and some conclusions from our own design experience are provided.
1. Diagrams and graphs instead of calculations.
Many designers mistakenly determine the Pressure (P) on the dictating sprinkler by calculation, depending on the sprinkler Performance Coefficient (Pr.) and the required Flow (Q) of this sprinkler. In this case, the required Flow is taken by multiplying the standard intensity by the area protected by the sprinkler, which is indicated in the passport of this sprinkler.
For example, if the required intensity is 0.08 l/s per 1 sq. m, and the area protected by the sprinkler is 12 sq. m, then the sprinkler flow rate is assumed to be 0.96 l/s. And the pressure required on the sprinkler is calculated using the formula P = (d/10*Kpr.)l2.
This option would be correct if the entire volume of water coming out of the sprinkler would fall only on its protected area and at the same time be evenly distributed over the entire given area.
But in fact, part of the water from the sprinkler is distributed outside the given area protected by the sprinkler. Therefore, to correctly determine the pressure on the dictating sprinkler, it is necessary to use only irrigation diagrams or passport data, which indicate what pressure needs to be created in front of the sprinkler so that it provides the required intensity in the protected area.
This requirement is specified in part 1 of paragraph B.1.9 of Appendix “B” to SP 5.13130:
“...is determined taking into account the standard irrigation intensity and the height of the sprinkler location according to irrigation diagrams or passport data, the pressure that must be ensured at the dictating sprinkler...”.
2. Why is the dictating sprinkler not the main one?
The flow rate of the entire section is often taken by simply multiplying the minimum protected area (specified in table 5.1 SP 5.13130 for sprinkler AUP) by the standard intensity or simply by the minimum required flow rate specified in tables 5.1, 5.2, 5.3 SP 5.13130.
Although at present, in accordance with the calculation methodology set out in Appendix “B” to SP 5.13130, it is necessary to first correctly determine the flow rate of the most distant and highly located sprinkler (dictating sprinkler), then calculate the pressure loss in the area from the dictating sprinkler to the next one, then taking into account these losses, calculate the pressure on the second sprinkler (after all, the pressure on it will be greater than on the dictating one). Those. it is necessary to determine the flow rate of each sprinkler located on the area protected by this installation. It is necessary to take into account that the consumption of sprinklers installed on the distribution network increases with distance from the dictating sprinkler, because The pressure on them also increases as they approach the location of the control unit.
Next, you need to sum up the flow rate of all sprinklers per protected area for a given group of premises and compare this flow rate with the minimum (standard) flow rate specified in tables 5.1, 5.2, 5.3 SP 5.13130. If the calculated flow rate is less than the standard one, then the calculation must be continued (taking into account subsequent sprinklers placed on the pipelines) until the actual flow rate exceeds the standard value.
3. Not all jets are the same...
The situation is similar when determining the costs of fire hydrants when designing a combined water fire extinguishing installation and an internal fire water supply system.
Primary costs for fire hydrants are determined according to tables 1 and 2 of SP 10.13130, depending on the purpose of the object and its parameters (number of floors, volume, degree of fire resistance and category). But in the second paragraph of paragraph 4.1.1 of SP 10.13130 it is stated that “Water consumption for fire extinguishing, depending on the height of the compact part of the jet and the diameter of the spray, should be specified according to Table 3.”
For example, for a public building, 2 jets of 2.5 l/s were determined. Further, according to Table 3, we see that a flow rate of 2.6 l/s can be provided with a fire hose length of 10 m only at a pressure of 0.198 MPa in front of the fire hydrant valve DN65 and with a fire hose tip spray diameter of 13 mm. This means that the flow rate previously determined for each fire hydrant (2.5 l/s) will be increased to at least 2.6 l/s.
Further, if we have more than one fire hydrant (two or more jets), then, by analogy with the calculation of a sprinkler installation, it is necessary to calculate the pressure loss in the area from the first (dictating) fire hydrant to the second. Then it is necessary to determine the actual pressure that the valve of the second fire hydrant will have, taking into account its geometric height, length and diameter of the pipeline. If the pressure is greater than on the first PC, then the flow rate of the second PC will be greater. And if the pressure is less, then it is necessary to make an appropriate adjustment to the pressure on the first PC so that the pressure on the valve of the second PC corresponds to the previously accepted (refined) values according to Table 3 of SP 10.13130.
If there are three or more fire hydrants (jet) involved in the system, then the calculation of such a system becomes much more complicated and is very labor-intensive to carry out manually.
4. Fine for speeding.
When carrying out a hydraulic calculation of the AUVPT, it is important, in addition to calculating the main parameters (pressure and flow), to take into account several other significant parameters and ensure that they are also normal. For example, the maximum speed of movement of water or foaming agent solution in pressure (supply, distribution, supply) pipelines must not be exceeded more than 10 m/s, and in suction pipelines - more than 2.8 m/s.
It is worth noting that the higher the flow rate, the higher the speed, which means that when performing the calculation, as you move away from the dictating sprinkler and approach the control unit, the speed in the branches and rows will increase. Consequently, the diameters of the distribution pipelines accepted at the beginning of the calculation for branches with a dictating sprinkler may not meet the speed parameters for the branches at the end of the calculated protected area.
5. This is our pantry, but we don’t store anything here at all.
In accordance with notes 1 and 2 of Appendix “B” to SP 5.13130:
"1. Groups of premises are defined by their functional purpose. In cases where it is impossible to select similar industries, the group should be determined by the category of the premises.
Everything seems to be clear with this and, as a rule, does not raise questions. However, further in Note 3 it is stated that if a warehouse is built into a building whose premises belong to the 1st group, then the parameters for such (storage) premises should be taken according to the 2nd group of premises.
For example, in a shopping center or regular store, group 2 may include the so-called pantries, utility rooms, wardrobes, linen and other storage rooms, in which the specific fire load ranges from 181 to 1400 MJ/m2. (category VZ).
Consequently, if the specified rooms of different groups are protected by one fire extinguishing section, then the designer must first make calculations for all rooms of the 1st group, then separate calculations for each room of the 2nd group, then select the dictating parameters of this section and do not forget to adjust the pressure and flow rate for design sections that are not dictating.
By the way, further in note 4 it is indicated that if the room belongs to the 2nd group of premises, and the specific fire load is more than 1400 MJ/m2. or more than 2200 MJ/m2, then the irrigation intensity should also be increased by 1.5 or 2.5 times, respectively. This case relates more to industrial protection facilities, but requires that, with the calculation of water fire extinguishing, a calculation of the categories of premises for explosion and fire hazards must be carried out in parallel.
6. And this pipe can be ignored...
A very rare practice
This is a calculation of pressure loss in the supply pipeline (from the control unit to the pressure pipe of the fire pump). As a rule, calculations are usually carried out at best up to the control unit, although depending on the diameter of the supply pipeline and the number of control units installed on it, pressure losses in this section can be very significant.
7. By leaps and bounds.
The maximum distance between sprinklers is often mistakenly taken according to Table 5.1. SP 5.13130, i.e. 4 or 3 meters respectively. However, to ensure uniform irrigation, the maximum distance between the sprinklers (when arranged in a square) should be no more than the side of the square inscribed in the circle formed by the area protected by the sprinkler. For example, with a protected area of 12 sq. m. the calculated distance between sprinklers will be only 2.76 meters.
8. Three at a hundred in one glass.
There is no calculation of the number and capacity of pipes for connecting mobile fire fighting equipment (fire trucks), taking into account the maximum flow rate generated by one fire truck per such pipe. The bottom line is that a standard fire truck (for example, an AC-40(130) tank truck) has a centrifugal pump with a flow rate of 40 l/s, but it can only deliver this flow rate through two pressure pipes (20 l/s each). Even a monitor carried on a tanker truck with a flow rate of 40 l/s is also connected to the vehicle through two fire hoses.
9. The fire may NOT be in the furthest room.
There is no comparison of the required flow and pressure depending on the location of the calculated protected area. It is necessary to consider at least two options: in the most remote part of the section (as indicated in the SP 5.130130 method), and, conversely, in the one located directly next to the control unit. As a rule, in the second case the consumption is greater.
10. And finally, again about the deluge curtain...
Deluge curtains connected to the pipelines of a fire extinguishing sprinkler system are rarely calculated in full, and their consumption is formally accepted at the rate of 1 l/s per 1 m of such a curtain. At the same time, the distances between deluge sprinklers are also taken to be unreasonable and without taking into account the mutual effect of neighboring sprinklers on each protected point. Here, as when calculating a sprinkler installation, it is necessary to take into account the increase in the flow rate of each sprinkler with distance from the dictating one (towards the location of the control unit), sum up these costs, and then adjust the resulting flow rate taking into account the actual pressure at the point of connection of the deluge curtain pipeline with the general pipeline system installations.
This video demonstrates and examines 10 common mistakes that are made when carrying out hydraulic calculations of water fire extinguishing installations. Video in two parts. Total duration is about 1 hour.