Design of fire-fighting water supply equipment

We've completed the development of the project and installation of the internal fire fighting water supply system in the production laboratory building in Moscow.

DESIGN OF FIRESUPRESSION SYSTEM

In order to effectively solve fire extinguishing tasks, the internal fire extinguishing system must meet a number of requirements of regulatory and governing documents determining the composition, number and placement of fire fighting equipment.

When developing the draft of the internal fire-prevention water mains of the building of the research institute, the requirements of the following regulatory documents were taken into account:

1. SNiP 2.04.01-85 *. Internal water supply and sewerage buildings. - M .: stroiizdat, 1996; 

2. SNiP 2.04.02-84 *. Water supply. External networks and facilities. Minstroy of Russia - Moscow: GCPTs, 1996;

3. SNiP 31-05-2003. Public administration buildings;

4. SNiP 21-01-97 *. Fire safety of buildings and structures;

5. PPB-01-03. Fire safety regulations in the Russian Federation. - M .: Infra-M, 2003;

6. Reference Designer. Internal sanitary facilities. Part 2. Plumbing and sewage. - M .: stroiizdat, 1990;

7. NPB 151-2000. Fire cabinets. - M .: State Border Service of the Ministry of Internal Affairs of the Russian Federation, 2001;

8. NPB 152-2000. Fire equipment. Pressure fire hoses. - M .: State Border Service of the Ministry of Internal Affairs of the Russian Federation, 2001;

9. NPB 153-2000. Fire equipment. Heads connecting firefighters. - M .: GPS of the Ministry of Internal Affairs of the Russian Federation, 2001.

10. NPB 154-2000. Fire equipment. Valves of fire hydrants. - M .: State Border Service of the Ministry of Internal Affairs of the Russian Federation, 2001;

11. NPB 177-99. Trunks fire manual.

12. SNiP 11-01-95. Instructions on the procedure for the development, coordination, approval and composition of project documentation for the construction of enterprises, buildings and structures. M .: 1995;

13. PUE-98. Rules for electrical installations.

2. LIST AND CHARACTERISTICS OF PROTECTED APT OF PREMISES.

Administrative, laboratory and utility rooms belonging to group F 4.3 for functional fire danger are subject to protection by internal fire suppression pipelines (Section 5.21 * SNiP 21-01-97 *). The building is accepted IIdegree of fire resistance, CO class constructive fire hazard. The building is five-storey with an attic and basement with a volume of 20,000 m3.

The premises are heated.

3. PURPOSE OF THE SYSTEM OF THE INTERNAL FIRE-PREVENTION WATER SUPPLY.

The water extinguishing system includes an internal fire-fighting network with fire hydrants and a fire pump station.

The arrangement of fire hydrants should ensure the irrigation of any point of the protected premises with one water jet with a flow rate of at least 2.5 l / s.

4. HYDRAULIC CALCULATION OF THE INTERNAL FIRE FIGHTING PIPELINE.

In accordance with clause 6.1 * and table 1 * SNiP 2.04.01-85 *, since the volume of a scientific research institute building is less than 25 thousand m3, 1 jet with water consumption of at least 2.5 l / s should be taken for internal fire extinguishing of premises . Based on the standard flow rate and the number of fire jets, determined in accordance with regulatory documents, the total water consumption for internal fire extinguishing will be: Qвн. = 1 · qст. = 1 ´2, 5 = 2.5 l / s.

It is proposed to equip the water supply network with fire hydrants with a diameter of 50 mm, fire barrels RS-50 with nozzles diameters 13 mm, fire hoses with a length of 20 m and a diameter of 51 mm. In accordance with paragraph 6.8 of SNiP 2.04.01-85 *, free pressure at the internal fire hydrants should provide compact fire jets with the height necessary to extinguish a fire at any time of day at the highest and remotest part of the building. The smallest height and radius of the compact part of the fire jet should be taken equal to the height of the room, counting from the floor to the highest point of overlap (coverage), but not less than 6 m for public buildings up to 50 m high.

At the same time, in accordance with Table 3 of SNiP 2.04.01-85 * with the actual size of the compact part of the fire jet R к. = 12 m, the water consumption will be 2.6 l / s, and the required pressure from the fire hydrant will be Npk. = 21 m. The range of the fire hydrant R kr. for indoor research institutes, Fig. 4.1., Will be:

 R kr. = R pr.K. + l p,

 where: R pr.k - the projection of the compact part of the jet on the horizontal plane, m;

T - room height (T = 2.6 m for the basement of the building, T = 3.6 m for the above-ground premises of the building);

l p - the length of the fire hose, m;

1.35 - the height of the location of the fire hydrant, m.

 - angle of incidence of the fire brigade, °.

Taking into account the height of the room, the radius of action of the fire hydrant in the basement of the building will be equal to R cr under. = 25.9 m, in the above-ground premises of the building - R kr nadz. = 25.5 m.

With this value of R to in the premises of the building of the scientific research institute, taking into account its planning, it is required to install 15 fire hydrants.

Since the total number of fire hydrants in the building of the scientific research institute is more than 12, the main network is designed to be circular and is powered by two inputs from the external water supply network.

From the calculated axonometric scheme of the internal fire water supply network for fire hydrants located on the attic floor of the building of the scientific research institute, fig. 4.2, it is clear that for the calculated direction one should take the direction of water movement from the fire pump to the crane PK-14 (dictating point).

Determine the diameters of the pipes of the risers to skip the estimated water flow, taking into account the economic speeds of water movement ( V ), which should not exceed 3 m / s.

The diameters of the pipes are determined by the formula:

Taking for the calculated value of the speed of the movement of water V = 2 m / s, for the risers and the ring network of the internal fire-prevention pipeline of the internal fire-prevention water supply network we get: 

We accept for the calculation of the pipe, taking into account their many years of future operation, “new steel” with a diameter of 50 mm.

The diameter of the supply piping (from fire pumps to the internal annular fire suppression pipelines) is taken d dit. = 80 mm.

Determine the required pressure of the fire pump:

Ntr. pos. = 1.1 · h with + NPC + Δ z - HB.,

where: h with - the loss of pressure in the network of internal fire pipelines;

Npk - free head at the dictating point (at the fire cock PK-14);

Δ z - the difference between the marks of the installation of the fire cock PK-14 and the pump axis;

Hsv. = 10 m - free pressure in the external water supply network at ground level (mark 0.00).

Since the fire cock with the dictating point is set at mark. 20.67 m, and the pumping station is located at mark. 0.00 then:

Δ z   = 20.67 m.

As follows from the results of the calculation of the pressure loss in the network in the design direction (PK-18 - NS) will be:

h с = h PK-14 - 1 + h 1-2 + h 2-3 + h 3-НС = 1.65 + 1.95 + 0.52 + 0.49 = 4.61 m,

where:  h PK-14 - 1 = А50 · L PK-14 - 1 · Q 2PK-14 = 0.01108 · 22 · 2.62 = 1.65 m;

        h 1-2 = A50 · L 1-2 · Q 2PK-14 = 0.01108 · 26 · 2.62 = 1.95 m,

        h 2- = A50 · L 2-3 · Q 2PK-14 = 0.01108 · 7 · 2.62 = 0.52 m,

        h 3-НС = А80 · L 3-НС. · Q 2PK-14 = 965.6 · 75 · 0.00522 = 0.49 m,

where: A50 = 0,01108 (s / l) 2; A80 = 965.6 (s / m3) 2 - the resistivity of pipes with a diameter of 50, and 80 mm.

The main project indicators are presented in Table. 4.1.

Table 4.1

From where the required pump head will be equal to:

Ntr. pos. = 1.1 · 4.61 + 21 + 20.67 - 10 = 36.74 m.

To ensure protection of the premises with one water jet with a flow rate of 2.6 l / s and the creation of the required head for fire hydrants, it is necessary to install two pumping units (1-n main and 1-n standby) of brand C R 15 - 3 with 3 kW electric motors, providing 10 m3 / h (2.8 l / s) and a pressure of 40.0 m.

 5. DEVICE AND OPERATION PRINCIPLE OF THE INTERNAL FIRE FIGHTING FIELD.

Fire hydrants should be installed at a height of 1.35 m above the floor of the room and placed in cabinets with ventilation holes, fittings for their sealing and visual inspection without opening. The source of water supply for the internal fire water supply is the city water supply network.

Internal fire water supply should be made in the form of a ring network of pipelines and operated in the heated premises of the public administration building. Starting buttons for starting the fire pumps and opening the electric valve on the bypass line of the water meter unit are installed in the fire cabinets. When remotely turning on fire pumps and electric shutters, it is necessary to simultaneously send a signal (light and sound) to the fire station room or another room with around-the-clock attendant staff.

When you press the start button (turn on the fire pumps and open the electric shutter) and open the valve of the fire hydrant, water under excessive pressure (pressure determined by calculation) will provide fire extinguishing of any building premises with the calculated number of jets. The fire pumps are switched on manually from the pump control panel in the fire pump station and remotely from the buttons installed in the fire cabinets. In the absence of a working pump to the design mode from the ECM installed on the pressure line of the main pumping unit, the standby pump is automatically turned on. All pipelines are made of steel electric welded pipes according to GOST 10704-91.

6. SELECTION OF EQUIPMENT FIRE PUMPING STATION.

The equipment was accepted in accordance with the requirements of SNiP 2.04.01-85 *, SNiP 2.04.02-84 * and the calculations performed. Two pumping units (one working and one standby) of brand C R 15 - 3 with electric motors with a power of 3 kW, providing a supply of 10 m3 / h (2.8 l / s) and a pressure of 40.0 m To remove spilled water, a GNOM 10/10 drain pump with a 1.1 kW electric motor is used.

7. CALCULATION OF THE NUMBER OF THE SERVICE PERSONNEL.

Plumber (fitter-repairman) of the 4th category - 1 person.

Electrician of the 4th category - 1 person.

The calculation is made according to RTM 25.488-82.

8. SAFETY REQUIREMENTS DURING OPERATION OF PUMPING FIRE EXTINGUISHING INSTALLATIONS. 

Maintenance personnel are allowed to work after passing a safety briefing with an appropriate mark in the journal.

When operating the installation, the following rules should be followed:

1. To carry out repair work in the absence of pressure in the repaired unit.

2. Repair electrical equipment to produce after disconnecting the power supply.

3. All work at heights to perform in the composition of at least two people with the provision of safety equipment.

4. Cleaning and painting to produce when removing the voltage from the nearest current-carrying elements.   

5. When repairing, if necessary, portable lamps with a voltage not higher than 12V should be used.

9. REQUIREMENTS OF FIRE SAFETY RULES ON FIRE-FIRE WATER SUPPLY.

According to paragraph 92 of PPB 01-03, the general scheme of the fire-fighting water supply and the piping of the pumps should be hung in the premises of the pumping station. Each valve and fire pump booster should indicate their purpose. The order of activation of the booster pumps should be determined by the instruction.

 According to paragraph 1.2 and table 3 of the airbag 160-97, fire safety signs must be installed on the remote start buttons.

THE TASK

 for construction work 

For systems of internal fire-fighting water supply system:

1. The depth of the pipe laying of the outer sections of the water supply network (entering the building) from the ground surface to the pipe axis is not less than 1.90 m.

2. To make holes in the walls and ceilings of the building for laying pipes of internal fire-fighting water supply.

On the premises of the fire pumping station:

1. Foundations for pumping units С R 15 - 3, unit weight - 52 kg.

2. To make holes in the walls of the pumping station for laying pipes of internal fire-fighting water supply.

3. To remove possible spilled water, perform a drain pit with a size of 600x600x600 mm.

THE TASK

for the design of power supply of fire pumps

According to the degree of reliability of the power supply of the fire extinguishing installation, the consumers are category I

It is necessary to submit two independent inputs of electricity to the fire pump control cabinet - operating input No. 1, backup input No. 2, with a voltage of 380/220 V, frequency 50 Hz, with a capacity of 3 kW each.

Working input No. 3 and reserve input No. 4 with a voltage of 220 V, with a frequency of 50 Hz, with a power of 0,5 kW on a case of an electric lock valve ShZ-1.

Working input No. 5 and reserve input No. 6 with a voltage of 220 V, with a frequency of 50 Hz on the control panel.

Technical requirements

Reserve and working inputs should be laid on separate tracks, isolated from one another, in accordance with СН 174-75 p.11-17.

Indoors of the pumping station include: working, emergency and maintenance lighting (illumination from working lighting 75 lx, voltage 220 V; illumination from emergency lighting not less than 10 lx; voltage repair lighting 12 V), as well as telephone communication with a fire station.

Above the entrance to the pumping station should be a light panel "Fire Station".

THE TASK

 to protective earth

All metal parts of electrical equipment, normally not under voltage, but which may be under it due to insulation failure, are subject to grounding (zeroing). Grounding (zeroing) are subject to: electric motors, terminal boxes, switching cabinets, control panel and dispatcher control panel.

Resistance of protective grounding (grounding) should be no more than 4.0 Ohm.

Grounding (zeroing) must be performed in accordance with the "Rules for electrical installations" (ПУЭ); SNiP 3.05.06-85 "Electrotechnical devices"; requirements of GOST 12.1.030-87 and technical documentation of manufacturers of component parts.

Drawings lay out for download on request.

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