T2 Flashcards
In Relation to intruder alarm systems explain the function and operation of the Tamper Circuirt
The function of the tamper circuit is to generate an alarm condition when deliberate interference with the systems components is detected,
In a four wire zone circuirt when the front cover of one of the connected field sensors/contacts is removed an anti tamper device is triggerd by the opening of a dedicated tamper proof contact this change of state raises the alarm whether the alarm is set or unset
Design a intruder alarm system to provide security protection for a 3 bedroom house
Magnetic reed switch-Front door,kitchen door, garage door.
Remote keypad- inside front door and garage door.
Inertia sensor- ground floor and upstairs windows.
Passive infrared sensor- garage and 1st floor landing.
External bell- front of the house 1st floor.
Main control panel- garage
The maximum distance in metres between manual call points
60 meters
The maximum mounting height of manual call points above the finished floor level
1.2 meters
Four locations where manual call points within a building are mandatory
-at every final exit
-Accommodation stairways
-refuge areas
-staircase landings
-defined escape routes
Category L fire alarm systems are divided into 4 systems
L1- automatic detection in every space
L2- automatic detection in escape routes and adjoining rooms with special area added.
L3- automatic detection In escape routes and adjoining rooms.
L4- automatic detection in escape routes only
Maximum demand for electrical tariffs for industrial consumers:
1: the period of minutes in which the meter records the consumers highest level of electricity during the day.
2: the consequence for the consumer of their agreed maximum import capacity (MIC) is too low
1: 15 minutes
2:if the consumers MIC is too low, they may incur a excess capacity charge
State the type of earthing system which utilities a PEN conductor and identify the section of the earthing system where the conductor is employed.
TNCS earthing system
TNCS earthing system employs a pen conductor between the source of the supply and the consumers intake
Specify four types of alarm sensors typically found connected to a domestic intruder alarm system
panic attack button- exit/entry or bedroom
Magnetic reed switch contact- front or/and back door
Passive infra red sensor- hallway or upstairs landing
Inertia sensors- windows
Disadvantage of a closed detection loop circuit
An alarm contact sensor or terminal contacts could be potentially shorted out by a prospective intruder without any indication been given this would permit the opening of any of sensor contacts without raising the alarm
How to overcome a closed loop detection circuit
Connecting a EOL ( End of line) resistor across the supply after the last sensor provides monitoring for the both short and open circuit conditions and removes the danger
Distinguish between the two types of heat detectors normally connected to a fire alarm system
Fixed temperature- these are designed to operate when they reach a pre selected threshold temperature.
Rate of rise Temperature- these are designed to operate when the sensed temperature rises abnormally quickly
Suitable location/application for the installation for an ionisation smoke detector
Ionisation smoke detectors are suitable for use in areas containing flammable materials such as cloakrooms or janitor rooms, use these detectors where rapid open flame fires are likely
List 3 considerations which influence the choice of a fire alarm detector for a particular application
Cost of detector
The nature of the fire hazard
The speed of response required
Ease of maintenance
The minimum number of sounder/bell circuits that are required to be connected to a buildings fire alarm control panel
Two sounder circuits
