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From NFPA 72, 2002 Edition: “7.4.2.1* To ensure that audible public mode signals are clearly heard, unless otherwise permitted by 7.4.2.2 through 7.4.2.5, they shall have a sound level at least 15 dB above the average ambient sound level or 5 dB above the maximum sound level having a duration of at least 60 seconds, whichever is greater ...
The standard on fire classes is numbered EN 2 [1] and the series of standards on portable fire extinguishers is numbered EN 3. [2] The European standardization on fire detection and fire alarm systems started already in the 1970s. EN 54-1 and EN 54-5 were issued in 1976. [3] [4]
A fire alarm system can vary dramatically in price and complexity, from a single panel with a detector and sounder in a small commercial property to an addressable fire alarm system in a multi-occupancy building. BS 5839 Part 1 categorizes fire alarm systems as: [21]
A flame detector is a sensor designed to detect and respond to the presence of a flame or fire, allowing flame detection.Responses to a detected flame depend on the installation, but can include sounding an alarm, deactivating a fuel line (such as a propane or a natural gas line), and activating a fire suppression system.
Coded panels were the earliest type of central fire alarm control, and were made during the 1800s to the 1970s. A coded panel is similar in many ways to a modern conventional panel (described below), except each zone was connected to its own code wheel, which, depending on the way the panel was set up, would either do sets of four rounds of code until the initiating pull station was reset ...
The alarm transmission methods covered under UL 365 can be categorized under standard line security or encrypted line security. The systems are required to operate within the limits of Class 2 remote control and signal circuits as defined by the National Electrical Code, NFPA 70.
A fire alarm box, fire alarm call box, or fire alarm pull box is a device used for notifying a fire department of a fire or a fire alarm activation. Typically installed on street corners or on the outside of commercial buildings in urban areas, they were the main means of summoning firefighters before the general availability of telephones.
Quizlet's primary products include digital flash cards, matching games, practice electronic assessments, and live quizzes. In 2017, 1 in 2 high school students used Quizlet. [4] As of December 2021, Quizlet has over 500 million user-generated flashcard sets and more than 60 million active users. [5]