This article is the continuation of the, new Multipoint ASD detectors from Rafiki(short introduction) previously posted on our blog. Via this article you can find out more about the automatic calibration and the modes of detection offered by the Rafiki MultiPoint detectors (heat and smoke detection modes).
All modes are compliant with European detector type specifications, and are suitable for use in installations compliant with BS5839: Part 1: 2002, Part 6 2004 if used in conjunction with a "Twinflex Plus" system.
The Twinflex Intelligent conventional detector can be set to any one of the smoke or heat detection modes as well as a Combined Mode (Smoke 2 & Heat 2) where a smoke or heat source can trigger a fire decision.
This means the end user is given optimum fire protection, even if the installer is unsure of the use of the particular area where the detector is sited.
As part of the Twinflex system, all the Twinflex products including the Twinflex Multipoint detector feature an End of Line monitoring switch, which negates the need to install End of Line monitoring resistors.
The Sita Intelligent addressable detector is able to offer all the choices for detection or a combination of any listed to give a choice of up to 15 different settings.
It is set via a PC when programming the system. The Sita Multipoint also has an in-built loop isolator as well as an input/output facility for local control and switching.
The Multipoint Detector also has the unique benefit of an optional full-specification integral sounder. A 90dBA output can be achieved.
The Twinflex Intelligent two-wire detector can be set to 3 different sound patterns, as well as switched off, with 2 sound output levels.
The Sita Intelligent addressable detector has 7 different sound patterns and 3 volume settings.
Automatic Calibration
To ensure the detection capabilities of the Multipoint are never compromised it self-calibrates every 6 hours. It continuously monitors for dust contamination, until, over a period of time, depending on the environment, it reaches a point where the chamber becomes saturated.Before this can develop into a false alarm situation, the panel will indicate that a Multipoint needs attention on both the Twinflex and Sita systems.
To make maintenance easy, the Multipoint features a disposable optical chamber. This means the chamber can be simply thrown away, and replaced economically when necessary.
Rafiki Multipoint Reflected Optical Value
The Rafiki MultiPoint detector - modes of detection
- Smoke 1: Used where ionization detectors are normally fitted especially when there are high ceilings or risk of free burning fires (chemical stores etc), or fires that need to be detected extremely quickly.
- Smoke 2: Used where optical detectors are normally fitted when there is a risk of a smoldering fire and for escape routes.
- Smoke 3: This setting is designed for use in areas that are prone to nuisance alarms. The reduced sensitivity linked with a time delay feature means that a higher concentration of smoke needs to be present for a constant time period, before a fire decision is made (Fig 1). This setting, for example, is ideal for hotel bedrooms with ensuite shower rooms, the end user can change the setting from smoke 2 to smoke 3 if nuisance alarms are becoming a problem – whilst still offering optimum protection of a smoke detection setting, especially if this is what has been specified.
- Heat 1: (Rate of Rise) Used where a standard rate of rise detector would normally be used
- Heat 2: (Standard Fixed Temperature - 58ºC approx) Used where a standard fixed temperature heat detector would normally be fitted, suitable for kitchens etc
- Heat 3: (High Fixed Temperature - 90ºC approx) Used where a high fixed temperature heat detector would normally be fitted, suitable for boiler rooms etc.
Most of the above specs are taken from the Rafiki Technical Sheet on, The New Multipoint ASD detector from Rafiki.
