3.0 Home Security and Surveillance Systems...

Transcription

1 3 3.0 Home Security and Surveillance Systems Terms you ll need to understand: Remote access Bypass mode Quad ANSI/TIA/EIA-570 Video switchers Passive infrared sensor Charge coupled device (CCD) Zone layout Hard-wired RJ-31x Glass break sensor Camera resolution Lux rating CCTV Techniques you ll need to master: Connecting a quad switcher to a VCR and cameras Planning the installation of a smoke detector Identifying the location of a glass break detector Planning a security system zone layout Selecting locations for keypads Evaluating a wireless and hard-wired security system Selecting a proper password for a monitoring station Comparing the light sensitivity levels of various brands of surveillance cameras Identifying the components contained in a security control panel

2 128 Chapter... 3 A home security and surveillance system is an essential part of any modern automated home. The basic design of a security system begins with analyzing the needs of the inhabitants, surveying existing technology and hardware, reviewing system costs, considering monitoring choices, and finally planning the installation. In addition to perimeter and interior protection offered by a security system, surveillance monitoring includes features that enable the inhabitants to observe environmental conditions inside and outside the home when at home or away. In a home surveillance system, video cameras and display systems are considered by most contractors to be optional items. Subject to the homeowner s choice, surveillance equipment can function independently from the basic features included in home security monitoring. This chapter provides the information you will need to know as a home integrator for designing, integrating, and installing a home security and surveillance system. Design Considerations The design of a security and surveillance system should provide for the protection of the entire perimeter of a home as well as visual- and audio-based surveillance monitoring. Security system sensors are available that are designed to detect sound, window and door intrusion, air movement, body heat, motion, and other conditions that indicate an intruder is present. A good security system design should consider the best plan for existing homes as well as new construction. It should also consider the lifestyle of all the inhabitants, the location of valuables or any items to be protected, how the system is to be controlled, adequate smoke and fire alerting sensors, and the type of emergency response required. The design choices are numerous and varied due to advances in home security technology and the wide availability of compact, low-cost video surveillance systems. Wireless Security Systems Wireless home security systems use battery-powered radio transmitters and receivers to connect the various components such as cameras, sensors, area motion detectors, sirens, central controllers, smoke/fire detectors, keypads, and video displays. These types of security systems are usually available at a local hardware store or on the Internet and are often designed

3 Home Security and Surveillance Systems 129 for do-it-yourself installation. The basic advantages of wireless security systems are Wireless systems are easy to install They avoid the expensive and timeconsuming task of installing new wires in the walls of existing homes. Wireless systems enable you to take the components with you when moving to a new location. Wireless sensors are designed to transmit a unique identification code to a controller The controller learns the identity of each sensor and links it to an appropriate zone. Each sensor also transmits status information such as battery voltage, condition of the sensor switch, and other diagnostic messages. Some homeowner-installed wireless security systems can be set up to record a voice message and to call programmed numbers in the event of an alarm This saves the cost of a professional monitoring service. Wireless sensors, motion detectors, and video cameras can often be installed in locations that are not accessible for wired equipment. The basic disadvantages of wireless security systems are Wireless system design specifications can limit the distance between sensors, cameras, and the central controller. Wireless systems can be vulnerable to electromagnetic interference (EMI) in some locations. They require periodic replacement of batteries. Most professional builders recommend wireless systems as a last choice. Hard-wired Security and Surveillance Systems Hard-wired security and surveillance systems use wires installed inside the walls, attics, crawl spaces, and underground to connect the sensors to a central controller. Surveillance cameras or microphones are also wired to speakers, video switchers, and video display monitors. A hard-wired system design normally uses power from the home AC power wiring as the primary source. A rechargeable battery pack is used by the controller for backup during power outages. The main components of a hard-wired system are similar to a wireless system but without the radio receiver and transmitter components. They include a central control panel, sensors, one or more keypads, motion

4 130 Chapter... 3 detectors, smoke and fire sensors, cameras, camera switchers, video displays, and sirens. The advantages for a hard-wired security system are Hard-wired security systems are considered by most contractors to be more reliable than wireless systems. Hard-wired systems are usually installed by a professional security system contractor with warranties and maintenance support. Hard-wired systems avoid the problem of EMI and radio range limitations inherent in some wireless security systems. The hard-wired components are usually less visible and more aesthetically pleasing than wireless components. Hard-wired systems do not depend on batteries except for power failure backup protection. The disadvantages of a hard-wired security system are Hard-wired systems are more expensive than wireless systems. Hard-wired systems are usually leased from the company that installs the system. Unlike a wireless system, the hard-wired system remains an integral part of the home. The components are not capable of being moved to another home when the owner relocates. Problems can arise in the installation of sensors in existing homes where some areas are not accessible for pulling wires inside the walls. Remote Access Systems A remote access system provides the capability to monitor and control a home security system from a location away from the home. A telephone call to the home followed by a key number code allows the caller to obtain status information concerning environmental and alarm system condition. Remote systems can also be programmed to call a specific phone number when certain environmental conditions exceed an established threshold. A special synthesized voice response system provides the caller with an audible report. The caller, with proper coded inputs, can also perform all the same control functions from a distant location that are available on the keypad in the home. Features of remote access systems vary among vendors, but most systems have features similar to those listed here: Monitoring and reporting temperature inside and outside the home Reporting on any sensors that have exceeded preset thresholds

5 Home Security and Surveillance Systems 131 Reporting on the date and time of any alarm conditions that existed Monitoring loud noises that exceed a set time interval using a built-in microphone in the home security system Reporting the status of smoke alarms or heat sensors Fire Detection Systems Fire detection sensors are available in two categories called heat detectors and smoke detectors. They operate on a principle of detecting heat rise or smoke in the home and can be either hard-wired with voltage supplied by the AC power wiring or battery operated. Most fire detectors currently available are powered by 9-volt DC transistor radio batteries, 120-volt AC power wiring, or 120-volt AC power with battery backup. Wired-in smoke detectors connected to a fire or security system are usually powered by DC from the security panel. This gives the detectors a natural battery backup in the event of a power failure. Common voltages are 6v, 12v, and 24v DC with 12v DC being the most common. Some 120v AC units have the capability to interconnect so that when one unit activates, it causes the audible alarm in the other units to sound. Units can also be purchased that have a relay output for connection to any security system control panel or wireless transmitter. The most common types available in hardware stores operate as independent sensors that are battery powered, are not connected to the security system, and have their own audible alarm sounder. Heat sensors operate using a different technology from smoke detectors. The basic design features of each type are summarized in the following paragraph. Heat Sensors and Smoke Detectors Heat sensors are designed to detect a rapid rise in temperature. They also have a feature that sets off an alarm when a fixed temperature is reached. Smoke detectors do not react to heat but use one of two common sensor designs to detect smoke. An ionization type of detector forms an electrical path inside a small chamber with a very small amount of radioactive material. When smoke enters the chamber, the particles attach themselves to the ions and change the electrical current flow. A photoelectric type of detector works by using a photoelectric cell and a light source. The light does not usually reach the photoelectric cell, but when smoke is present the light is dispersed and reaches the photoelectric cell, triggering the alarm. The main difference between the two types is photoelectric types are more sensitive to large particles and ionization types are more sensitive to small particles.

6 132 Chapter... 3 Modern home design should include at least one of each type. Smoke and heat detectors should be located in each sleeping area and on each story of the home and placed on the ceiling or on the wall 6'' 12'' from the ceiling. Remember that heat and smoke detectors operate on different types of technology. Heat detectors react to abrupt changes and go into an alarm condition when a temperature changes rapidly or reaches a fixed value. Smoke alarms do not react to heat but go into an alarm condition when smoke enters the sensor area. The two main types of smoke detectors are ionization and photoelectric. Environmental Monitoring Environmental monitoring can be incorporated into the design of a home security and surveillance system to monitor the status of specific conditions. This might be applicable to rural homes, vineyard owners, farmers, fruit growers, and ranchers. Environment monitoring includes the tracking and measurement of external as well as internal parameters. The following are examples of the types of environmental data that can be monitored with existing sensor systems: Inside and outside temperatures Barometric pressure Frost alarm Minimum and maximum temperature memory Temperature trend indicator Humidity Emergency Response Systems An emergency response system is a valuable optional enhancement to a home security system. A large number of designs are available from which to choose, depending on the personal needs of members of the household. A personal emergency response system is usually designed for elderly or disabled individuals living alone who need to contact a doctor or relatives in an emergency with a minimal number of actions. Systems are available incorporating some or all of the following physical and functional features: Emergency response requests These are initiated by the user using a miniature wireless radio transmitter with a built-in help button carried or worn as a pendant by the user. Transmitters are lightweight, batterypowered devices activated by pressing one or two buttons.

7 Home Security and Surveillance Systems 133 A receiver console connected to the telephone This receives radio signals from the user s transmitter and dials an emergency response center number. An emergency response center This is similar to an alarm monitoring service except the personnel in an emergency response center are experienced medical response personnel. Temperature Sensors Temperature sensors are used as one component of an environmental monitoring and security system mentioned earlier. They are normally used to monitor high and low temperature values in vacation homes, water pipes, furnace and heating vents, outside farm buildings, computer equipment, utility rooms, or areas that might sustain damage with extreme temperature swings. Temperature sensors are often integrated with a central controller that includes a display, a keypad, and an automatic telephone dialer that can alert the homeowner or monitoring center when temperature limits are exceeded. Temperature sensors use a variety of electronic designs and components to measure temperature, including both analog and digital signal outputs that change value with a change in temperature and operate remote switches or active alarms. Location Considerations when Designing a Security or Fire Alarm System Each component of a home security and surveillance system is designed to be used in a specific location. Window sensors have requirements that are different from door sensor requirements, and smoke and heat detectors each have special location requirements. Computer systems can be integrated with control protocols such as X10 and CEBus to operate and manage security systems. In the following paragraphs, you will discover how smoke detectors work and where they are located. Also covered are the functional design requirements for various types of home security system components. Home Utility Outlet Specifications Home security systems require a number of utility outlets to support the installation of sensors, sirens, controllers, surveillance cameras, security lights, and motion detectors throughout the home. New construction provides the

8 134 Chapter... 3 opportunity to install structured wiring outlets in all rooms of the home. This includes 120v AC power outlets, Category 5 UTP cable outlets, #22-gauge two-pair wiring for sensors, and RG-6 coaxial cable outlets. Cohesion with Existing Home Systems The security system should have sensors located in areas where components of existing home systems require monitoring or protection from theft. Heat sensors are the most common type of sensor for monitoring components of the heating, ventilation, and air conditioning (HVAC) system. They are mounted near the furnace to monitor rapid changes in temperature that could warn of a possible fire. Security systems area often designed to be integrated with the home computer system. Computer interfaces are used with X10 and CEBus protocols to monitor and control interior and exterior security system components. Safety and Code Regulations The safety and code regulations for installing and locating fire alarms, sensors, and smoke detectors are usually governed by local building codes. The local codes are enforced by a fire marshal who conducts inspections of public places and sets the standard for local residential inspections. Smoke Detector Installation and Location Requirements On the national level, codes and standards have been published that establish the requirement for fire detection equipment installation. As an example, a home must have at least one smoke detector installed to meet National Fire Protection Association (NFPA) Rule 72 and Underwriters Laboratories, Inc. (UL) 985 standards. The UL 985 standard covers household fire warning system control units intended to be installed in accordance with the National Fire Alarm Code (ANSI/NFPA 72) and the National Electrical Code (ANSI/NFPA 70). ANSI/NFPA 72 is the standard document that defines the spacing for smoke detectors, which is typically 30 feet when installed on a smooth ceiling. Existing Home Environments Existing home environments require new wire and cabling to support security system components where hard-wired systems are installed. Wireless systems are popular for existing home environments because of the convenience of locating sensors without the need to install additional wiring in the walls.

9 Home Security and Surveillance Systems 135 Smoke Alarm Requirements Smoke alarm requirements are not the same for every home. They vary according to local municipal standards and the age of a specific dwelling. For homes built prior to 1979, battery-powered smoke alarms are permissible. As to smoke alarm placement, requirements also vary according to the age of the dwelling. New Home Construction Environments New home construction facilitates the location of hard-wired security system wiring and components during the early phase of the construction. Structured wiring in new homes supports most of the needs of a well-planned multizone security system. Phone lines, coaxial cable, and Category 5 cable are components of a structured wiring installation. They provide the basis for integrating the security system with the computer network and other home automation systems. The exception is the wiring for door, window, and motion detector sensors. Inexpensive two-conductor wire must be installed in the interiors of walls between the controller location and each sensor. In addition, two-pair #22- gauge wire must be installed for all low-voltage powered sensors such as motion detectors. One pair is used for power and the other pair is used for signaling. Smoke Alarms in New Home Construction For all new home construction, fire alarm sensors must be powered by the home AC power electrical wiring. Although this overcomes the problem of neglecting to replace batteries on a periodic basis, there remains the problem of power outages that would also disable a fire warning sensor that uses the home wiring as a power source. Sensors can be purchased with integrated battery powered backups. For homes built prior to 1979, battery-powered smoke alarms are permissible. In newer dwellings, alarms must be powered by the electrical wiring. The problem with battery units is that people often neglect battery replacement. On the other hand, what good are wired-in smoke alarms if you have an electrical fire accompanied by a power outage? The safest arrangement, therefore, is to install wired-in alarms equipped with battery backup. This type of integrated alarm can be obtained at most hardware stores and is required for homes built as of As to smoke alarm placement, requirements also vary according to the age of the dwelling. In older homes, most municipalities require alarms in the following locations: within close proximity to all bedroom entrances, on each story of a multilevel home, and in basements. The latest standards, enacted in 1993, require that there be an additional alarm in each bedroom. Another practical location, although not required, is the garage.

10 136 Chapter... 3 Equipment Functionality and Specifications Each component of a home security and surveillance system has a specific function to perform. The basic security system includes a control panel connected by cables to sensors at various locations throughout the home. A perimeter protection system must include sensors at every opening, including doors, windows, garage doors and windows, and doors to crawl spaces. A keypad is the device that provides a control interface for the residents to arm and disarm the system using a programmed access code and also to monitor the status of the system. Door Functional Design Specifications Doors are protected by installing small magnetic switches inside the frame. Figure 3.1 illustrates the location of the magnetic switch. A magnet is installed in the top of the door that keeps the switch contacts open as long as the door remains closed. An alarm is caused when this switch is disturbed by opening the door. The magnetic switch completes a circuit that is connected to the control panel. Recessed mounted models use magnets that are fitted into drilled holes, and when properly installed, recessed mounted magnetic switches are hard to notice and blend in well with the door. Figure 3.1 Magnetic door switch. Window Functional Design Specifications A perimeter security system must include a glass protection system because magnetic switches do not protect against an intruder entering through a broken window. Glass protection systems are available in two categories: vibration

11 Home Security and Surveillance Systems 137 and acoustical. The vibration system is mounted on the glass or on a nearby wall and detects movement of the glass. Acoustical systems, or sound discriminators, sense the sound of breaking glass. The unit can be tuned to react only to the specific frequency of glass breaking, typically 4KHz 6KHz, or it can react to any loud noise. Some manufacturers have combined vibration and sound detectors into one unit that does not activate unless both are detected. These units can be used where the normal conditions would cause a single technology detector to generate false alarms. Control Panel Functional Design Specifications The control panel shown in Figure 3.2 is an enclosure that contains all the electronic components, wire termination points, backup battery packs, and telephone termination wiring. Figure 3.2 Control panel. Each sensor receives power and is managed from the control panel. It monitors the health and operating status of the total system and sends a signal to the siren when an alarm condition exists. The panel should be mounted in a location that is out of plain view and near a 120v AC outlet where a plug-in transformer can be used to supply low-voltage power to the total system. If a phone line is planned for connection to an external monitoring facility, access to the location where the phone line enters the home must be considered when locating the control panel. Preferred locations are utility rooms, basements, and closets. Keypad Functional Design Specifications The best location for a keypad is an area that is both convenient to the family users and secure for the system. The homeowner must ultimately determine how many keypads are desired and where they are to be located in the home. Typically, keypads are placed at the main entry/exit door, in the master bedroom, or in the main hallway of the home. In a multilevel home, keypads are commonly placed on each level.

12 138 Chapter... 3 Physical Devices The six major physical components of a home security and surveillance system are described in this section. Although some designs include additional components for enhanced performance or custom installations, the physical devices described here are considered the basic building blocks for a security and surveillance system that will provide adequate protection from intrusion. The essential physical assemblies include Keypads Sensors Security panels Cameras Monitors Switchers Keypads The keypad is the device used by the home residents to initiate commands for control options and observe the status of the security system. As shown in Figure 3.3, it usually contains an alphanumeric keypad and LED displays that indicate the status of the alarm system. Figure 3.3 Keypad. The keypad is used to arm and disarm the system and often includes a panic switch by which the alarm can be triggered instantly in an emergency situation. The alarm can be silenced by the owner by entering the correct coded sequence of numbers on the numerical keypad. The keypad is typically installed inside the home near a door that is most frequently used by the residents. A programmed delay is included as a feature of most systems to enable the users to enter and disarm the system within a fixed delay period (normally seconds). The same fixed delay is also used to allow the user to arm the system and exit the home within the fixed delay period. Keypads can also be used to bypass certain areas. The bypass function is used to arm the system but disable selected zones or motion detectors inside the home when the family is present. Residents often desire to secure the perimeter area of doors and windows after retiring for the evening but need to bypass interior area motion detection sensors that are activated only when the home is not occupied.

13 Home Security and Surveillance Systems 139 Sensors Sensors are designed to protect both the perimeter and the open spaces inside the home. As mentioned earlier, perimeter devices primarily protect doors and windows. The most common perimeter sensors are magnetic door switches, window vibration detectors, and window acoustical detectors. Space protection sensors called motion detectors cover interior rooms and hallways and can detect an intruder who has been able to defeat a perimeter device. Exterior motion detectors and motion-activated security lights are also used. The following paragraphs describe the types of sensors required in basic home security and surveillance systems. Door Switches Door switches work on a basic principle of a two-part magnetic switch. A switch that is sensitive to a magnetic field is mounted on the fixed structure (frame), and wires from the switch are routed through the wall to the control panel. A magnet is mounted on the door in a position where it is in close proximity to the switch when the door is closed; this also keeps the switch closed. Opening the door moves the magnet away from the switch and causes the switch to open, which is sensed by the central control panel and activates an alarm. Magnetic switches are available as normally open (NO) or normally closed (NC) to accommodate different wiring designs and controller options. Window Acoustic and Vibration Detectors As you learned earlier, window sensors are used to detect the sound of breaking glass. Large glass doors such as patio doors are usually protected by magnetic switches. Windows in the home can also be protected by magnetic switches if they can be opened; however, glass break detectors are recommended by most home security contractors to protect against an intruder entering through a broken window. Glass break detectors are available in either vibration type or acoustical type. The vibration type is mounted on the glass or on a nearby wall. Security system magnetic switches are designed for both normally closed (NC) and normally open (NO) options. An NC switch opens when the magnet is moved near the switch, and an NO switch closes when the magnet is moved in close proximity to the switch. This enables magnetic sensor-type switches to be used with various types of security system designs. Sensor door switches wired in parallel use NO contacts so that any closure of the contacts in the circuit activate an alarm condition. Series circuits use NC magnetic switches where any opening of a switch results in an open condition for the circuit, which triggers an alarm condition by the controller.

14 140 Chapter... 3 Motion Detectors Motion detectors work by detecting the changes in the infrared energy in an area. Because these devices do not emit any energy, they are called passive infrared (PIR) detectors. PIR detectors use a lens mechanism in the sensor housing to detect a change in infrared energy across the horizontal sectors covered by the sensor. This type of detector is insensitive to stationary objects but reacts to rapid changes that occur laterally across the field of view. They are the most common and economical type of motion detectors and are available in standard, pet-friendly, and harsh-environment (outdoor) models. An example of a motion detector for interior use is shown in Figure 3.4. Figure 3.4 Motion detector. Security Panels Security panels provide several functions to coordinate the operation and management of a security system. They can include an integrated keypad or LED indicators. Most designs include a power transformer for converting the AC voltage to a DC voltage for the sensor loop and contain a rechargeable battery for backup if the commercial power fails. A terminal strip provides for the connection of the wiring that connects all the sensors to the controller as well as the external telephone line. Most designs include a printed circuit board containing all the electronics and a microprocessor. It also connects to and controls the siren that is activated when an alarm condition exists. Security panels are known by numerous names, such as central control box, control panel, alarm panel, and interface panel. They all perform similar functions including controlling and monitoring sensor status, providing power to the system, connecting the telephone line to the monitoring station, and handling the programmable options for the system.

15 Home Security and Surveillance Systems 141 Cameras Surveillance systems for the home use video cameras that convert the image into a video composite or S-video signal for display on a video monitor. The best type of camera for home systems uses charged coupled device (CCD) technology. These cameras have high resolutions, low operating light, less temperature dependence, and high reliability. A typical CCD camera used in video surveillance systems is illustrated in Figure 3.5. Figure 3.5 Video surveillance camera. Camera Resolution and Sensitivity The two important specifications for cameras are the light sensitivity rating and the number of lines of resolution. The resolution of a camera is a measurement of the horizontal lines it is capable of generating. Most standard TVs and VCRs have a resolution of fewer than 300 lines, but video monitors can have a resolution as high as 800 lines. Surveillance cameras come in a range of costs and are available with lines of resolution. Higher resolutions make distinguishing fine details and recognizing people at a distance easier. The amount of light required to obtain a reasonable image is called the lux rating. 1 lux is approximately the light from one candle measured from 1 meter. Typical camera ratings range between 0.5 and 1.0 lux. Monitors Monitors are cathode-ray tube display systems similar to computer display systems. They are used to display video information processed by the camera. Coaxial cable is used to connect the camera to the monitor that can be located in any area selected by the user. Monitors do not have a TV tuner and usually have better video resolution than standard television receivers. They can also be connected to programmable switchers that receive input from several cameras and show multiple images on a single monitor. Closed circuit TV (CCTV) monitors are available for black-and-white or color display depending on the resolution and camera selection. Black-andwhite monitors have resolutions in the range of lines, whereas color monitors are available with lines. CCTV monitors are designed for extended 24-hour-per-day operation.