Home Security Fire Alarm and fire fighting

 Home fires often cause heavy casualties and property losses. The designed home fire detection alarm and fire automatically fighting system can effectively prevent fire or reduce loss from fire. Home fire safety systems include fire detection and alarm, combustible gas detection and alarm, automatic sprinkler, portable fire hoses and fire extinguishers.

Automatic home fire alarm system adopts independent or network smoke detector and temperature detection alarm. Smoke detector must be installed in the living room and every bed room, study room and other rooms. Each smoke detector can protect about 40m2 area. The detector should be set in the center and kept at a distance of more than 0.5m from the lighting and other obstacles.
The fire detector can send sound and light alarm signal for alert. The network fire detector can send alarm signal to inform the security service center and safety person through the linked alarm host.
Smoke detector is not suitable to be installed in kitchen cause of much fumes there. Heat detector and combustible gas detector should be installed in the kitchen. It is better to install gas detector with solenoid valve to automatically shut off the gas source when gas leakage is detected.
The home sprinkler system includes fire pipes and sprinklers. There are ceiling mounted pendent sprinkler head and wall mounted sidewall sprinkler head. The installation interval of side wall sprinkler head is 2m-3.6m, and the distance between the nearest sprinkler head and the wall is not more than 1.8m.The protection span is 3.6m.

In order to deal with the initial home fire, a home type convenient fire hose should be equipped. The fire hose includes hose and water gun. The home fire hoses can obtain water from tap or fire lines or share a faucet with a washing machine.


The home fire safety system should also include a fire extinguisher. There are many types of fire extinguishers. ABC dry powder fire extinguishers are generally used in family house fires. When using a fire extinguisher, firstly remove the safety plug, hold the tip of the nozzle firmly in one hand. Then aim at the root of the flame, press down the pressure valve and spray dry powder to the flame.

Improvement of active infrared detector

 As a sensor detection device, the detector is used to detect the invasion behavior of intruders and various abnormal situations. There are many places that need security precautions in various smart buildings and ordinary buildings. These places also have a variety of safety purposes and requirements according to the actual situation.Therefore, a variety of alarm detectors are needed to meet different safety requirements.

In the burglar alarm field, infrared detection technology is one of the most widely used. There are active infrared detectors and passive infrared detectors.
Active infrared detectors are more applied on the outside wall fence or the outside of the building Windows protection. And generally it is with passive infrared detectors direction recognition technology together, used for protection of buildings, such as residential balcony door. The technology can automatically determine whether the user passes through the defense area from the inside and returns from the outside or enters the room directly from the outside. If users passes through from indoor to outdoor, it will not alarm. Otherwise, it will alarm. And it also gives an allowed return time without alarm. Over the return time, it is back to arm status. So, it makes the perimeter prevention more humanized.

Infrared detection medium has good anti-interference for the environment sound, lightning, vibration, all kinds of artificial light source and electromagnetic interference source. Only when the infrared beam is blocked, the alarm will be triggered. So the active infrared intrusion detector is widely applied for perimeter security protection.
Active intrusion detection of infrared technology products are: traditional active infrared intrusion detector, frequency discrimination type of active infrared intrusion detector, infrared curtain wall, which are respectively applied to the analog pulse modulation, multi-frequency point pulse modulation, pulse modulation based on the code modulation. The difference is that the products have different prevention heights. The first two types of active infrared intrusion detectors have low (about 30 cm) prevention height and clear single-direction prevention direction. The infrared wall protection height can reach to 2 meters or higher, which can realize both sides intrusion and defense direction is hidden.
Active infrared detector technology mainly adopts infrared light transmitting and receiving, which belongs to linear prevention.The transmitter of the active infrared detector sends out a modulated infrared beam, which is received by the infrared receiver, thus forming a warning line consisting of an infrared beam.When encountered leaves, rain, small animals, snow, dust, fog cover will produce a false alarm. Now the active infrared detector has been developed from the original single beam to multi-beam, using multi-frequency point transmission, frequency conversion transmission and other technologies, to minimize the false alarm rate, so as to enhance the stability and reliability of the product.

The application of solar wireless infrared detector technology is a new starting point of detector development. Solar infrared detector has built-in rechargeable lithium battery, and the power is supplied by solar panels, and the energy consumption is very low. Even in rainy weather, it can be used normally with the stored power for 20 days. In this way, solar energy can be recycled without laying power cables.Generally speaking, solar panels are amorphous silicon and do not require direct sunlight to generate electricity.In addition, solar panels can provide much more power than they consume in light, allowing them to operate without light at night and in continuous rainy weather.

Solar infrared beam, solar infrared fence and solar infrared wall make good use of solar power supply and wireless transmission, and become all wireless active infrared beam perimeter protection products. It solved the troubles of construction and maintenance of active infrared beam system.

Connect solenoid valve with gas detector

 Gas is the main energy source for heating and cooking in daily life. Now almost every household has installed gas pipeline, which provides great convenience for daily life.However, gas is also associated with certain dangers, especially in the case of improper use and caused gas leakage, which may lead to fire or explosion.One would ask, Can nobody know when a gas leak occurs?State regulation requires gas must do smell treatment before sent to the user’s home. It is to prevent gas leakage without notice of people. In many cases, the gas has accumulated in the space to the point that a small flame or friction spark can trigger a fire or explosion when user discovers a gas leak.What to do in this situation?Gas alarm can prevent gas leakage, the gas level has not reached the point of fire, alarm will go off to remind users. The effective rate of accident prevention is more than 90%.Usually everyone is working out of home, or go out for travelling, how to prevent accident when people is not at home?The gas alarm is connected to the solenoid valve. When gas leaks, the gas leak detector drives the solenoid valve to automatically close and cut off the gas source.Even if no one is at home, the security system will ensure the personal and property safety of you and your family at all times and avoid the disaster of fire and explosion caused by gas leakage.

Take natural gas as an example. When the concentration of natural gas in the air is within the range of 5% ~ 15%, it will mix with the air (or oxygen) evenly. At this time, if it encounters a small flame or friction, it will explode.Other types of gases have different explosion minimum valve. If the gas alarm is connected with solenoid valve, once it detects that the gas concentration in the air reaches 5%LEL (explosion limit) or above, the gas alarm will send signals to the connected solenoid valve and drive it to work and turn off the gas source.
Because the solenoid valve is driven to work by the gas detector, if the detector installation position is not correct, it will cause a false alarm, and indirectly lead to the wrong solenoid valve work.So the installation position of the detector must be correct. It should be installed at different position according to the gas to be detected. After the correct installation, you can press the alarm test button to check whether the alarm is running normally.The schematic diagram of proper installation of the gas alarm is shown as follows:

Gas leakage shut off valve can be divided into manipulator and solenoid valve. According to the use of object manipulator can be divided into pipe manipulator and cylinder manipulator. Solenoid valve can be divided into pipe solenoid valve and hose solenoid valve.

Pipeline manipulator is relatively easy to install, just install it in the gas pipeline valve switch.When receiving the signal from the gas alarm, the manipulator will automatically close the gas pipeline valve switch.

The cylinder manipulator is used for cylinder liquefied gas, which is installed between the cylinder and the pressure reducing valve. When receiving the signal from the gas alarm, the manipulator will automatically block the gas output channel to prevent the gas from being output again.

Pipeline solenoid valve is installed in gas pipeline. The pipeline between the gas meter and the pipeline inlet should be cut off and install the solenoid valve (this is a professional operation, must be installed by professionals of gas company, otherwise accident consequences may be caused). When receiving the gas alarm signal, the solenoid valve internal slider will slide down to block passage of gas, when disarmed, need to manually upward reset button, to restore the normal use of fuel gas.

Hose solenoid valve can be used for the hose of liquefied gas tank or hose gas pipe, used for liquefied gas bottle. Solenoid valve is installed between the pressure relief valve and hose, different from the pipe solenoid valve is the former has straight valve, hose solenoid valve has a head for the pointed nozzle valve, and the same principle of work as the pipe solenoid valve.

How to design a 1000 channel large-scale monitoring system

 How to design large-scale surveillance system? For example, how to design 1000 channel monitoring system? Today, we will discuss how to design 1000 channel video surveillance monitor system of hardware configuration.

The 1000 channel video surveillance system is a medium to large-scale security project. There are four main problems we should solve to build up the 1000 channels video surveillance system.
1.What camera is it used?
2.How to choose the switchboard? How to build up the network?
3.How to arrange storage properly?
4.How to display the 1000 monitor videos?
We will analyze one by one.
1.What camera is it used?
Generally, more than one type of camera is used in the 1000 channel surveillance solution. Different types and functions of security cameras are selected according to the application environment.

Security camera types:
A.Bullet camera: both hoisting and wall mounting are acceptable, and a protective cover is generally required for outdoor installation. Generally it is installed in the corridor, in the factory or outdoor areas such as parking lots. It is mainly used in underground warehouses, warehouses, monitoring urban roads, community outdoor area.
B.Dome camera: Actually, it is “integrated movement(zoom lens+camera) shield+PTZ+PTZ protocol decoding”. It is generally used outdoors or indoors where the area is relatively large and the scope is relatively wide.
C.Dome camera: It is ceiling installed. Mostly it is used in indoor small-scale monitoring areas without lights or relative dark including semi-public areas such as hotel corridors, hospitals, communities, elevators, indoor halls and other places.
D.Infrared integrated camera: a surveillance camera with infrared night vision probe, which can be widely used in day and night and large-scale surveillance areas, such as communities, supermarkets, squares, banks, factories, military camp schools and other places.
Suitable camera should be selected according to actual application of the security project. The cameras have different resolutions and code rate showed as below:

2.How to choose Ethernet switch?
The focus of the 1000 channel monitoring project is the choice of switches. Here we choose a three-layer network structure. The structure is the access layer-the convergence layer-the core layer. Compared with the two-layer network structure, the three-layer network structure has larger scale and longer transmission distance. The network expand ability is stronger.The topology is as follows:

I The code stream of a single camera is generally calculated at 4Mbps, and the peak value is 6-8M. The peak value should be considered when selecting the model.
II The transmission bandwidth utilization rate is about 60%, so 100M bandwidth is about 60M utilized.
Sum up the above two points, a 100M switch can generally be equipped with 8 cameras, and Gigabit up switches should be used for cameras with more than 8 channels.
According to the layout of the front-end, centralized or decentralized, switches with different port numbers from 8 to 24 may be used. According to the installation environment, industrial-grade switches may also be used.
B.The choice of aggregation layer switch
The aggregation layer is a link between the access layer and the core layer. Compared with access layer switches, higher performance, more interfaces and higher switching speeds are required. Attention points in the selection and design of the aggregation switch:
Switch Bandwidth: For the 1000 channels cameras, if the aggregation layer has 8 switches, then each need to deal with 125 cameras 4M bit stream(125 * 4M = 500M), which means aggregation layer switches need to support both forward 500Mor more Exchange capacity.Taking into account the different access equipment of the front-end switch such as 100M, Gigabit, electrical or optical ports, it is advised to choose a Gigabit photoelectric hybrid switch.
Backplane bandwidth: Each aggregation layer switch will be connected to at least 5 Gigabit switches. In order to ensure sufficient bandwidth, the switch backplane bandwidth requirement is:(5*1000M*2)/1000=10Gbps backplane bandwidth.
Packet forwarding rate: the packet forwarding rate of a 1000M port switch is 1.488Mpps/s, and the exchange rate of the switch at the aggregation layer is:5**1.488Mpps/s=7.44Mpps.
According to the above conditions: when 1000 cameras are connected to the network, the aggregation layer needs to meet the backplane bandwidth not less than 10Gbps, packet forwarding rate is greater than 7.44.
C.Selection of core switch
The core switch is mainly responsible for data forwarding and network structure setting functions, and has higher requirements for switching capabilities, network management functions, and stability. In addition, because the storage device is at the core layer, the switching capacity of the switch and the bandwidth and high-speed forwarding capability of the core link need to be considered. So the following conditions must be met:
Bandwidth: The bandwidth of 1000 channels of monitoring is at least 1000*4Mbps=4000Mbps. It is recommended that the core switch a high-bandwidth Gigabit or 10 Gigabit switch, and the uplink port is 10 Gigabit to make the data smooth.
Backplane bandwidth: The core switch will have at least 8 Gigabit ports from the aggregation layer, 2 uplink 10 Gigabit ports, and 4 possibly connected to other Gigabit ports, so there are a total of 12 Gigabit ports and 2 A 10G port, in order to ensure sufficient bandwidth, the bandwidth requirements of the switch backplane are:
(12*1000M*2+2*10000*2)/1000=64Gbps backplane bandwidth.
Packet forwarding rate: The packet forwarding rate of a gigabit port is 1.488Mpps/s, and the packet forwarding rate of a 10 megabit port is 14.88Mpps/s, in order to ensure wire-speed forwarding, there will be at least 12 Gigabit ports and 2 10 Gigabit ports, the exchange rate of the core switch is:
12*1.488Mpps/s+2*14.88Mpps/s=47.56Mpps.
According to the above conditions: when 1000 cameras are connected to the network, the core layer switch must at least meet the backplane bandwidth of not less than 64Gbps, and the packet forwarding rate must be greater than 47.56Mpps.
In addition, for the core switch, also need to consider system expand ability, number of slots, module type, module redundancy, routing redundancy, etc.
3.1000 channel monitoring storage design:IP-SAN
For the storage of 1000 channel monitoring system, NVR and hard disk alone are not enough. IP SAN storage can be used. IP SAN is a kind of SAN. It has large capacity and can connect to hundreds of videos, but the price is more expensive, so we choose IP SAN, that is, disk array+hard disk.

So, when it comes to the 1000 channels full HD IP real time monitoring, how much data will be stored? About 4Mb of 30FPS video stream of network Camera per second. Each NVR has 42 channels of real-time video streams, and 1000 channels of high-definition video streams are all transmitted to the APT dual-control 10Gb disk array, generating 4Gb of data per second.
A camera with a code rate of 4M has a storage capacity of about 48G a day. So 1000 Ge 7 storage days is: 1000 Cameras *48G*7=395136G=328T or so.
Calculated on a 4T hard disk, it shows about 3700GB on the computer, with h.265 encoding format,96 hard disks can be used, and it is enough. For this 96 drives, every 4 drives can compose a RAID5, consisting of 24 RAID groups. We use 16 bay network storage IP SAN disk array, 6 can be OK.
In addition to storage capacity, for large-scale public monitoring systems must also consider its expand ability and ease of management, so IP SAN is the most ideal solution.
4.1000 channel monitor display design
How to display 1000 channels of monitoring? Monitoring display walls are generally chosen for Large-scale monitoring projects. The monitoring center has a management platform, which needs to be equipped with a comprehensive monitoring integrated platform, which requires strong decoding capabilities and powerful functions. The number of previews on the wall depends on the specific needs. You don’t need to finish all of them, you can do rounds.

Another key point of the 1000 channel monitoring system is the allocation and setting of IP addresses.
5. conclusion
In general, the design principle of the 1000 channel video surveillance system is: based on the premise that the system is stable, reliable, and expandable, the surveillance screen is required to be free from freezing, image interruption, and security and confidentiality.
When planning and building up the network systems, should overall consider the camera streams, network bandwidth, data transmission volume, specific network environment, as well as user specific requirements of the monitoring system and other factors. At last properly make the 1000 channel surveillance design and select the appropriate monitoring equipment.