AS 7240.22 pdf download
AS 7240.22 pdf download.Fire detection and alarm systems
1 Scope
This document specifies requirements, test methods and performance criteria for smoke-detection equipment for ducts (SDED) for use in fire detection and alarm systems installed in buildings (see ISO 7240-1). The SDED samples the air from a duct and detects smoke in the sample. NOTE 1 A common method of operation is to use differential pressure arising from airflow in the duct. The SDED can use smoke detectors complying with ISO 7240-7 or other detectors complying with tests specified in this document. A common application for SDED is to detect visible smoke, for which detectors using scattered light or transmitted light can be more suitable. However, requirements for detectors using ionization are also included in this document for use in applications where detection of less visible fire aerosols is desired. For the testing of other types of smoke detectors or smoke detectors working on different principles, this document can be used for guidance. Smoke detectors with special characteristics, developed for specific risks, are not covered. NOTE 2 Certain types of detectors contain radioactive materials. The national requirements for radiation protection differ from country to country and are not specified in this document.
4 Requirements
4.1 Compliance In order to comply with this document, the SDED shall: a) meet the requirements of Clause 4, which shall be verified by visual inspection or engineering assessment; b) be tested as specified in Clause 5, and shall meet the requirements of the tests; c) meet the requirements of Clauses 7 and 8, which shall be verified by visual inspection. 4.2 Visual alarm indication 4.2.1 Each SDED shall be provided with a red visual indicator, by which the SDED can be identified when the associated detector releases an alarm and which remains illuminated until the alarm condition is reset. Where other conditions of the SDED can be visually indicated, they shall be clearly distinguishable from the alarm indication, except when the SDED is switched into a service mode. The alarm indicator may be the smoke detector indicator provided the indicator is visible when the detector is in situ as part of the SDED. 4.2.2 The visual indicator shall be visible from a distance of 6 m in an ambient light intensity up to 500 lx at an angle of up to a) 5° from the axis of the detector in any direction, and b) 45° from the axis of the detector in at least one direction. 4.3 Connection of ancillary devices The SDED may provide for connections to ancillary devices (remote indicators, control relays, etc.), but open- or short-circuit failures of these connections shall not prevent the correct operation of the SDED. 4.4 Monitoring of detachable detectors For detachable detectors, a means shall be provided for a remote monitoring system (e.g. the fire detection control and indicating equipment) to detect the removal of the head from the base, in order to give a fault signal.4.5 Manufacturer’s adjustments It shall not be possible to change the manufacturer’s settings except by special means (e.g. the use of a special code or tool) or by breaking or removing a seal. 4.6 On-site adjustment of response behaviour 4.6.1 If there is provision for on-site adjustment of the response behaviour of the SDED, then a) for all of the settings at which the manufacturer claims compliance with this document, the SDED shall comply with the requirements of this document and access to the adjustment means shall be possible only by the use of a code or special tool or by removing the SDED from its base or mounting; b) any setting(s) at which the manufacturer does not claim compliance with this document shall be accessible only by the use of a code or special tool, and it shall be clearly marked on the SDED or in the associated data that if these setting(s) are used, the SDED does not comply with this document. 4.6.2 These adjustments may be carried out at the SDED, the detector or the control and indicating equipment. 4.7 Requirements for software-controlled smoke-detection equipment for ducts 4.7.1 General The requirements of 4.7.2 and 4.7.3 shall be met for SDED that rely on software control in order to fulfil the requirements of this document. 4.7.2 Software design In order to ensure the reliability of the SDED, the following requirements for software design shall apply. a) The software shall have a modular structure. b) The design of the interfaces for manually and automatically generated data shall not permit invalid data to cause an error in the program operation. c) The software shall be designed to avoid the occurrence of deadlock of the program flow.
