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Jargon Buster

Letter R


Radio-interlinked smoke and heat alarms allow multiple alarms to be connected without wires between the individual alarm units. In the case of fire, a message is passed from unit to unit and all alarms sound together. This ensures that all parts of a building are notified of a fire alarm situation.

The interlink is created through radio-frequency signals. Our radio-interlinked smoke and heat alarms pass a digitally coded message between units that ensures that only units within the intended circuit go off together. Neighbouring circuits or other radio-frequency devices can therefore not interfere or cause false alarms.

Radio-interlinked smoke alarms are sometimes also called RF (radio-frequency) or wireless smoke alarms.

Rate of Rise Heat Detectors

Rate of rise heat detectors have a thermistor arrangement which is designed to activate if the sensing element detects a rapid rise is temperature.

Also see Heat Detector | Fixed Temperature Heat Detector

Rated Duration

The manufacturers declared duration for a battery operated emergency lighting unit, specifying the time for which it will operate after mains failure. This may be for any reasonable period, but is normally one or three hours (when fully charged).

Real CPR Help®

The Real CPR Help® feedback tool provides the first aider with audio and visual prompts as a step-by-step guide. The tool is able to monitor the actions of the first aider and provides feedback to ensure that CPR is performed effectively.


A channelled groove, recess or step that is cut along the edge or face of a timber structure, e.g. a door or door jamb, in order to receive another part, such as a fire door seal.

Reflected Beam Detectors

A reflected beam detector contains the transmitter and receiver in the same unit (transceiver). The transmitter emits a signal which is reflected back to the transmitter using a reflector positioned at the opposite end of the area to be protected.

Also see Beam Detector | End to End Beam Detector

Refurbished CO2 Extinguishers

Our refurbished CO2 fire extinguishers are subjected to intensive testing during the refurbishment process. The 20 step process involves stress and pressure tests to ensure the integrity of the cylinder, sand-blasting, re-painting and labelling, and finally the installation of a brand new head valve assembly.

Refurbished CO2 Extinguishers - Environmental Impact

Because the cylinders are being re-used and not manufactured, the impact on the environment is considerably lower. The raw materials and energy consumption used during the refurbishment process is just a fraction of that used during the manufacture of a new cylinder.

Resettable element with alarm flag

The "alarm flag" is a yellow indicator which makes it easier to identify which call point has been pushed.

Reverse Polarity Monitoring

Sounders are voltage polarity conscious and will only operate in the correct polarity. To monitor the sounder circuit, the polarity is reversed so as not to operate the sounders but still monitor the sounder circuit.

Rim Devices

A rim device is the easiest and most common form of exit or panic hardware. The device is fitted to the interior face of a door and latches to the rim of the door frame. When used on a double door assembly on the first opening leaf it is necessary to use a “double door strike” which replaces the rim of the door.