General: Fire Safety Technology (10) Water Mist Fire Extinguishing System

System components (devices) check before installation

First, the arrival of the nozzle inspection

After the water mist sprayer arrives at the site, the on-site inspection of the appearance, sealability, and quality deviation of the sprayer should be emphasized. The physical map of different types of water mist nozzles is shown in Figure 3-6-2 -1 .

(a) check the contents

1. Sprinkler sign inspection

Inspection requirements: Marks, models, manufacturers and production dates of the nozzles are complete and clear.

2. Number of nozzles checked

Inspection requirements: The number of nozzles meets the design requirements.

3. Appearance inspection

Inspection requirements:

( 1 ) The appearance of the nozzle is free of machining defects and mechanical damage;

( 2 ) There is no flaw, burr, missing thread or broken thread on the thread sealing surface of the nozzle.

(b) Inspection methods

Check the contents of " 1. " to " 3. " According to different models and specifications, check 1% and not less than 5 respectively ; when there are less than 5 , check all.

Second, the valve group approach check

After the product of the zone control valve group arrives, check its appearance quality, valve quantity and operation performance.

(a) check the contents

1. Visual inspection

Inspection requirements:

( 1 ) Marks, models, and specifications of each valve are complete;

( 2 ) The valves and their accessories have no processing defects and mechanical damage;

( 3 ) The permanent parts of the control valve marked with the direction of the water flow are marked.

2. Quantity check

Inspection requirements: All valves and accessories are fully equipped, and the model and specifications meet the design requirements.

3. Operational performance check

Inspection requirements:

( 1 ) The flaps of the control valve and the operating mechanism are flexible and free of jamming;

( 2 ) The valve body is clean and free of foreign matter.

System components installation, debugging and inspection

The installation and debugging of the water mist fire extinguishing system includes installation of water supply facilities, pipe network and system components, system pressure test and flushing, and system commissioning.

First, the system main components installed

(a) nozzle

1. Installation conditions

( 1 ) The nozzle installation must be performed after the system pipeline pressure test and purge pass;

( 2 ) Special wrenches should be used for installation.

2. Installation requirements

( 1 ) During the installation, the manufacturer's mark, model, specification and orifice direction should be checked one by one according to the design documents;

( 2 ) The nozzle shall not be dismantled and changed during installation, and any decorative coating shall not be added to the nozzle;

( 3 ) The nozzle installation height, spacing, and ceiling, doors, windows, openings or obstacles meet the design requirements;

( 4 ) nozzles without a decorative cover shall not expose ceilings at the end of the connecting pipe; nozzles with a decorative cover shall adhere to the ceiling;

( 5 ) Nozzles with an external filter should not extend into the branch pipe;

( 6 ) The connection between the nozzle and the pipeline should be sealed with an end face or an O -ring. The sealing material should not be PTFE, hemp, or adhesive;

( 7 ) The sprinkler head shall be installed when it is installed on a nozzle that is vulnerable to mechanical damage.

(b) Control valve group

1. Installation requirements

( 1 ) The installation of the valve group shall comply with the relevant provisions of GB 50235 " Code for Construction of Industrial Metal Pipeline Engineering" ;

( 2 ) The installation position of the observation instrument and operation valve of the valve group should meet the design requirements, and mechanical, chemical or other damage should be avoided, and it is easy to observe, operate, inspect and maintain;

( 3 ) The opening and closing signs on the valve group should be easy to identify;

( 4 ) Before and after the valve group, the pipe, the bottle support frame, and the electric control box need to be fixed firmly and must not be shaken;

( 5 ) The installation height of the zone control valve should be 1.2m~1.6m , and the distance between the operation surface and the wall or other equipment should not be less than 0.8m , and should meet the operation requirements;

( 6 ) The installation of the zone control valve opening control device should be safe and reliable.

(III) Other components

1. Installation requirements

( 1 ) Pressure regulators should be installed in place where the network pressure may exceed the maximum rated working pressure of the system or system components. The valve shall open when the system pressure reaches 95% of the maximum rated working pressure of the system components;

( 2 ) Pressure gauges shall be installed on both sides of the pressure regulating valve, the pressure side of the water supply equipment, and the pressure side of the automatic water control valve. The measurement range of the pressure gauge should be 1.5 times to 2 times the system working pressure;

( 3 ) When the compressed gas pressure supplied to the water mist fire extinguishing system is greater than the design working pressure of the system, a compressed gas pressure relief pressure regulating valve shall be installed. The set value of the valve is set by the manufacturer, and there shall be measures to prevent misoperation and a permanent mark for correct operation;

( 4 ) The installation position of the closed system test valve should be easy to check and test;

( 5 ) The control circuit layout and protection of the water mist system, and the installation of the fire automatic alarm system and other linkage control devices linked with the system shall comply with the provisions of the national standard “Code for Construction and Acceptance of Automatic Fire Alarm Systems” GB50166 .

2. Inspection method

Observe the inspection, check the size and operate the valve check.

System debugging and field function testing

The debugging of the water mist fire extinguishing system is completed after the system construction, and the technical parameters meet the design requirements, and the automatic fire alarm system is completed after debugging. The system debugging mainly includes the debugging and linkage test of the pump set, the regulated pump, and the zone control valve.

The system debugging is performed by professional technicians who are familiar with the principle and operating methods of the water mist fire extinguishing system, and prepare the necessary debugging equipment according to the national engineering quality supervision and inspection requirements. Before the system is debugged, it is necessary to write a debugging outline according to the specific conditions of the system. The debugging outline includes the debugging content, debugging methods, debugging steps, and debugging inspection equipment. After the system is qualified for commissioning, the construction unit shall fill out the commissioning records and provide the construction unit with quality control data and all construction process inspection records. At the same time, use compressed air or nitrogen purge after commissioning to restore the system to quasi-operating conditions.

(I) System debugging preparation

System debugging requires the following conditions:

1. The fire alarm system or other devices and power supplies that are linked to the system and the system are in quasi-operating state, and the on-site safety conditions meet the requirements for debugging;

2. The necessary inspection equipment for system debugging is complete, and the instruments and meters required for debugging are qualified and connected with the system and fixed;

3. Have the commissioning program approved by the supervision unit.

(two) system debugging requirements

1 partition control valve debugging

The partition control valve is commissioned according to the respective characteristics of the open system and the closed system partition control valve. Before commissioning, it is necessary to first check whether the components of the zone control valve or valve group are fully installed, whether the components are installed correctly, and the installation is in accordance with the design. After the requirement and the fire technical standards are stipulated, carry out debugging.

2. Linkage test

For the protection zone allowing the spray or protected, at least in the actual mist blow 1 test zone; protection zone for the protected object is not allowed or spray, mist spray discharge simulation test.

( 1 ) Content and Requirements of Linkage Test for Open System

When the actual water mist spray test is conducted, a simulated fire signal activation system is used to check whether the zone control valve, pump group or bottle group can act in time and send a corresponding action signal. The system's action signal feedback device can issue a system start in time. The feedback signal indicates whether the nozzle in the protection area or the protected area of ​​the protection object emits fine water mist, and whether the warning light at the entrance of the corresponding place is actuated.

When simulating the water mist spray test, manually open the bleed test valve and use the simulated fire signal activation system to check whether the pump group or the bottle group can act in time and send corresponding action signals. Whether the system's action signal feedback device can be timely A feedback signal from the start of the system is issued and the warning light at the entrance of the corresponding place is activated.

Inspection method: observation and inspection.

( 2 ) Linkage test contents and requirements of closed system

Closed system linkage test can use the test valve to discharge water for simulation. Open the test valve to see if the pump set can start in time and send a corresponding action signal; the system's action signal feedback device can promptly send the system start feedback signal.

Inspection method: Open the test valve to release water, observe and check.

( 3 ) Fire alarm system linkage function test

When the system needs to be linked with the fire automatic alarm system, the fire signal can be used for testing. Give a simulated fire signal to check whether the fire alarm device can automatically send out an alarm signal. Whether the system operates or not, whether the associated linkage control device can issue an automatic shutdown command, and whether the relevant flammable gas or liquid supply source that needs to be closed in case of a fire shuts down will be linked to other facilities. Shut down.

Inspection method: simulate fire signal, observe and inspect.

System acceptance

The acceptance of the system shall be jointly conducted by the construction unit, such as supervision, design, and construction.

The system acceptance mainly includes the acceptance of the installation quality of the main components such as the water supply source, pump group, gas cylinder group and water bottle group, control valve, pipe network and nozzle, as well as the functional acceptance of the system. Through system acceptance, the functions of the main components of the system are ensured to meet the design requirements, providing reliable protection for the normal operation of the system in the future.

After system acceptance, it is necessary to restore the system to normal operation, and hand over construction acceptance documents and system engineering acceptance records to the construction unit. Those who fail to pass the system acceptance shall be re-accepted after rectification.

(II) On-site sampling inspection and functional testing

1. Simulation linkage function test

( 1 ) Test requirements

1 The action signal feedback device should be able to operate normally, and should be able to start the pump group after the action or open the bottle group and the associated equipment associated with it. The feedback signal can be correctly issued.

2 Open system partition control valve should be able to open normally, and can send feedback signals correctly.

3 The flow and pressure of the system should meet the design requirements.

4 The pump group or bottle group and other fire-fighting linkage control equipment should be able to start normally and should have feedback signal display.

5 The main and standby power supplies should be able to switch normally within the specified time.

System maintenance management

First, system common fault analysis

When performing periodic system checks, it is necessary to timely analyze the cause of the fault and eliminate the fault to ensure that the system is intact and effective.

(I) Analysis and Treatment of Common Failures of Pump Sets

1. There is leakage at the pump assembly connection

2. Low pump outlet pressure

( 1 ) Failure Analysis

1 pump set test valve is not closed;

2 Inverted input power to the pump unit;

3 high-pressure pump damage;

4 The usage flow exceeds the rated value.

( 2 ) Troubleshooting

1 Close the pump set test valve;

2 Adjust the phase sequence of the incoming power supply;

3 replace the high pressure pump;

4 Operate within the pump set rating.

3. The pump set does not start

( 1 ) Failure Analysis

1 high pressure pump contactor is not closed;

2 The pump set stops the contacts open;

3 LOGO ! Not executing the program;

4 power is not connected;

5 water level protection.

( 2 ) Troubleshooting

1 Closed contactor;

2 Close the pump set stop contact;

3 maintenance LOGO ! Replace if necessary;

4 power on;

5 Restore the tank water level.

4. Regulator pump starts frequently

( 1 ) Failure Analysis

1 pipeline leakage;

2 safety relief valve seal is not good;

3 test valve is not closed;

4 Check valve seals adhere to impurities.

( 2 ) Troubleshooting

1 Leakage point of pipeline leakage;

2 maintenance safety relief valve;

3 completely close the test valve;

4 Clean the check valve and clean the tank and piping.

5. Regulated pump can not restore pressure within the specified time

( 1 ) Failure Analysis

1 residual air in the pipeline;

2 pipeline leakage;

3 high pressure ball valve leakage;

4 regulator pump outlet pressure is low;

5 Regulator pump is damaged.

( 2 ) Troubleshooting

1 completely eliminate the air pipe;

2 leakage of pipeline leakage;

3 See below for troubleshooting of high pressure ball valve leakage;

4 Regulator pump pressure adjustment screw;

5 Replace the regulated pump.

(III) Analysis and Handling of Common Failures of Partition Control Valves

2. The bottle group system partition control valve manual starting device can not operate

( 1 ) Failure Analysis

When the solenoid valve is used as the zone control valve in the bottle group system, the electromagnetic activation valve is equipped with a manual emergency starting device. In case of an emergency, the manual safety pin is pulled out. When the manual button is clicked, the starting valve can be actuated and the starting device sprays out the fire. . After the electromagnetic valve is tested, the spring of the operating mechanism is in a state of being pressed. To prevent malfunction during installation, commissioning and transportation, the operating mechanism is locked by the auxiliary safety pin and it is easy to forget to pull out the system after it is put into use. Out of the insurance pin, the electromagnetic activation valve action mechanism cannot operate.

( 2 ) Troubleshooting

After the system is installed and commissioned and put into use, the auxiliary insurance pin must be pulled out, and this job must be explicitly written into the system operation management operation and maintenance procedures of the user.

3 electric valve does not move

( 1 ) Failure Analysis

1 power wiring connection is bad;

2 exceeds the allowable range of the power voltage;

3 The valve core is mixed with impurities and stuck;

4 Electric device burned or short circuited.

( 2 ) Troubleshooting

1 Press the power wiring;

2 Adjust the voltage within the allowable range;

3 cleaning valve core;

4 Replace the electric device.

(4) Analysis and handling of common failures of water mist nozzles

1. The spray nozzle is not normal

( 1 ) Failure Analysis

1 There are impurities in the pipeline to block the nozzle;

2 nozzle working pressure is low.

( 2 ) Troubleshooting

1 See nozzle fouling solutions below;

2 Ensure that the working pressure of the nozzle is not less than its minimum design working pressure.

2. Sprinkler

( 1 ) Failure Analysis

1 The quality of water supply is irrational, and sand and dirt are found in the water.

2 The environment where the nozzle is located is more dust and impurities.

( 2 ) Troubleshooting

1 Before the nozzle is installed, the pipe network should be purged, and the sand and dirt etc. at the nozzle filter should be cleaned after each use.

2 After the completion of the test, apply a grease with a consistency rating of 4 to 6 on the nozzle hole , a drop point of at least 95 °C , a rust-preventive grease, or other dust-proof measures.

The information in this article comes from the Internet and was reorganized and edited by China Rescue Equipment Network.