AS 7240.4 pdf download
AS 7240.4 pdf download.Fire detection and alarm systems
5 Requirements
5.1 General 5.1.1 The PSE shall have safety characteristics in accordance with IEC 60950‑1 for protection against direct and indirect contact, for the separation of the extra low voltage DC circuits from the low voltage AC circuits and for earthing of metal parts. 5.1.2 All outputs shall have appropriate power limitations in order to ensure that in case of external short circuits no danger exists because of heat production. 5.2 Compliance 5.2.1 In order to comply with this document, the PSE shall meet the following requirements. a) Clause 5, which shall be verified by visual inspection or engineering assessment, shall be tested in accordance with Clause 6 and shall meet the requirements of the tests. b) Clauses 8 and 9, shall be verified by visual inspection. 5.2.2 If an optional function with requirements is included in the PSE, then all the corresponding requirements shall be met. 5.2.3 If functions other than those specified in this document are provided, they shall not jeopardize compliance with any requirement of this document.5.3 Power sources 5.3.1 General 5.3.1.1 There shall be at least two power sources for the power supply of the FDAS: the main power source and the standby power source. 5.3.1.2 Each power source, on its own, shall be capable of meeting the PSE manufacturer’s output specification or, in the case of an integrated the PSE, shall be capable of operating the equipment in which it is integrated within its specifications. 5.3.1.3 Switching from one power source to the other shall not cause any change in status or indications within other equipment of the FDAS, other than those relating to the power supply. 5.3.1.4 Failure of one of the power sources shall not cause the failure of any other power source or the failure of the supply of power to the FDAS. NOTE The compatibility of the separated PSE with the other equipment, for example, FDCIE, is dealt with in ISO 7240-13. 5.3.2 Main power source 5.3.2.1 The main power source shall be designed to operate from the public electricity supply or equivalent system. 5.3.2.2 When the main power source is available, it shall be the exclusive source of power to the FDAS, except for currents associated with battery monitoring. 5.3.2.3 If the main power source fails, then the PSE shall automatically switch over to a standby power source. When the main power source is restored, the PSE shall automatically switch back to the main power source. 5.3.2.4 When operated from the main power source, the following shall apply. a) The PSE shall be capable of operating in accordance with its specification given in the manufacturer’s data, irrespective of the condition of the standby power source. This includes any charge condition of the standby power source, or open circuit or short circuit of the connection to the standby power source. b) The PSE shall be capable of continuously supplying P a, max and simultaneously charging a battery discharged to its final voltage. 5.3.3 Standby power source 5.3.3.1 At least one standby power source shall be a rechargeable battery. 5.3.3.2 When operated from the standby power source, the PSE shall be capable of operating in accordance with the specification given in the manufacturer’s data. The PSE shall be capable of supplying P c, max , irrespective of the condition of the main power source, and with an internal resistance of the battery and its associated circuitry, e.g. connections, fuses (see 6.4) equal to R i, max . NOTE Standby periods and alarm periods for specific applications are specified in ISO 7240‑14 and ISO 7240‑19, or other national design and installation standards where they take precedence.5.3.3.4 If the battery is mounted in a cabinet which houses other FDAS equipment, then it shall be of the sealed type and shall be mounted in accordance with the manufacturer’s data. 5.3.3.5 When operating from a standby power source, the PSE shall have a facility to switch off the PSE output if the output voltages or the voltage of the battery falls below a value specified by the PSE manufacturer.
