ISO 7240-25 Fire Detection and Fire Alarm Systems - Part 25: Components Utilizing Radio Transmission Paths

The standard "ISO 7240-25 Fire detection and fire alarm systems - Part 25: Components using radio transmission paths" published by the International Organization for Standardization (ISO) describes the requirements, test methods and performance criteria for components used in fire detection and alarm systems installed in buildings and their surroundings and using radio frequency (RF) transmission paths. This standard defines a procedure for assessing the conformity of components with the requirements of this standard.

This standard also specifies requirements for the system when components work together and this requires knowledge of the system design.

When the fire detection and alarm system uses wired and RF transmission paths, the relevant parts of ISO 7240 apply together with ISO 7240-25. The requirements for wired transmission paths are superseded or replaced by those in this standard. This standard does not restrict:

• Intended use of the radio spectrum, such as frequency, power output of devices
• The maximum number of components allowed using RF transmission paths or single-wire transmission path or RF transmission path within the fire detection and alarm system.
• Maximum allowable number of components affected by single-wire transmission path or RF transmission path loss

For the purposes of this standard, the following terms and definitions apply in addition to those given in ISO 7240-1:

• Adjacent channel selectivity is a measure of the ability of a receiver to operate satisfactorily in the presence of an unwanted signal that differs from the desired signal by an amount equal to the adjacent channel separation for which the equipment is intended.
• An antenna is the element of a radio component of a fire detection and alarm system that allows connection between the component and the medium in which RF waves propagate.
• The assigned band is the frequency band in which the equipment is allowed to operate.
• Autonomous power supply is power supply equipment that does not have any connection to the public power supply or equivalent system and cannot be recharged during operation and is capable of powering the given component by itself.
• The base station is the transceiver in the system that communicates with a certain number of components.
• Blocking or desensitization is the measure of the ability to receive the desired modulated signal without suffering distortion due to the presence of an unwanted input signal, any frequencies outside of spurious responses or adjacent channels or bands.
• Collisions are simultaneous transmissions from two or more transmitters belonging to the same system with sufficient signal strength to cause the information carried by the RF transmission path to be corrupted or erased through mutual interference.
• Compatibility is the ability of a component of a system to operate with another component of that system within the limits specified by each component, or the ability to operate within the limits specified by the manufacturer or the relevant parts of the ISO 7240 standard, or the ability to operate within the specified configurations of the system.

The requirements of this standard apply together with the requirements of the relevant part of ISO 7240, where the RF transmission path component has the same function as the component covered by that part and unless otherwise specified in this standard. For example, a component with an RF transmission path that has a heat detector function must comply with ISO 7240-5, and a component with a manual call point function must comply with ISO 7240-11.

The manufacturer shall provide means, either in the component itself or in the system configuration, to ensure that ground attenuation due to effects occurring on site from other causes does not adversely affect the RF transmission path such that communication between the components is not possible. Immunity to ground attenuation shall be specified as follows:

• At least 10 dB for RF operating frequencies up to 10 MHz
• As calculated in Annex B for RF operating frequencies greater than 10 MHz

The manufacturer must provide the necessary documentation or evaluation tools that allow the full functionality of the component to be evaluated. If these tools are part of the component, the user must not be able to interfere with them.

The components of the system use a transmission protocol in the transmission path to ensure that no alarm messages are lost.

Each component using the RF transmission path is identified by a unique identification code as belonging to a specific fire detection and alarm system. The manufacturer shall provide means to ensure that a component using the RF transmission path is not accepted by other fire detection and alarm systems.

In terms of receiver performance, the receiver must meet the requirements shown in the table given in the standard, unless otherwise specified in mandatory national regulations.

The purchaser's manufacturer must provide a test report to demonstrate that the requirements of this subclause are met. If he is unable to provide such a report, the tests described in this standard must be performed.

To comply with this standard, components must meet the requirements of this standard, be verified by visual inspection or engineering evaluation, be tested in accordance with this standard, and meet the requirements of the tests.

Among the numerous testing, measurement, analysis and evaluation studies that our organization has carried out for businesses in various sectors, it also provides testing services defined in the “ISO 7240-25 Fire detection and fire alarm systems - Part 25: Components using radio transmission paths” standard with its trained and expert staff and advanced technological equipment.