GB2516073A

GB2516073A - Fire Safety Light

Info

Publication number: GB2516073A
Application number: GB201312392A
Authority: GB
Inventors: Andrew Cunningham; Steven Kallagher; Andrew Slater
Original assignee: LITE4LIFE Ltd
Current assignee: LITE4LIFE Ltd
Priority date: 2013-07-10
Filing date: 2013-07-10
Publication date: 2015-01-14
Also published as: GB201312392D0

Abstract

A wall mounted emergency lighting unit includes a sound sensor for detecting sounds in a specific frequency range associated with a fire or smoke alarm. Upon detecting sounds indicative of a fire or smoke alarm, the lighting unit is illuminated. The lighting unit may comprise an array of LEDs arranged to indicate an exit direction. The LEDs of the array may be of more than one colour and may be arranged in a pattern to indicate an exit direction. The lighting unit may be mounted at a height of not more than one metre above the floor level, and the fire or smoke alarm may be mounted in a position remote from the lighting unit.

Description

FIRE SAFETY LIGHT

This invention relates to a safety light system for domestic, commercial or industrial premises, designed to facilitate the evacuation of a building in the event of fire.

Conventional emergency lighting is generally located on walls or ceilings of public buildings and the like that have emergency escape routes. Emergency lighting is actuated on power failure, which may occur in the event of any emergency. Fire is however usually accompanied by smoke, which tends to rise within a building, masking or obscuring ceiling mounted light fittings. Domestic premises, hotels and office buildings in particular often have low ceilings so that smoke accumulates in passages and rises up stairwells, darkening the building, reducing visibility and causing disorientation for people trying to escape. Fire fighting can also be dangerous during a building sweep as high-level wall or ceiling lighting is obscured by smoke. Even a small fire can generate large quantities of smoke, with a result that smoke logging can occur throughout a building even when the fire has not spread far. Death and injury can also result from smoke while occupants are trying to evacuate a building, before the fire has taken hold.

WO 2005/079340 discloses a directional fire alarm system which identifies a threat such as a fire and illuminates a low-level directional lighting system to direct occupants to the nearest exit.

The present invention provides a safety lighting system comprising a plurality of wall-mounted lighting units at a height of not more than one metre preferably 500mm from the floor or more preferably 400mm, the lights indicating an emergency exit direction and being activated by the sound generated by at least one fire or smoke alarm. The alarm may be of any suitable type such as a ceiling-or wall-mounted sounder or bell.

Each wall mounted lighting unit has a sound sensor tuned to detect a frequency pattern in the sound generated by the fire or smoke alarm, so that it is triggered by the alarm and not by other extraneous noises. A smoke alarm is typically ceiling-mounted and should normally be fitted in accordance with BS 5839.

Depending on the location, a single unit or a series of lighting units may be arranged to be triggered by more than one fire or smoke alarm. Thus for example a long corridor may have a series of the lighting units at intervals along the lower parts of a wall and a series of ceiling mounted smoke alarms, each of the smoke alarms being arranged, when activated, to illuminate all the lighting units in the corridor.

In a hotel for example each room is normally fitted with a smoke alarm, and according to the invention the alarm in each room could be arranged to switch on a lighting unit positioned to indicate the door since a hotel occupant sleeping in an unfamiliar room full of smoke may be disoriented and therefore need guidance to find the exit. A smoke alarm triggered in a room may be arranged automatically to illuminate all the lighting units in the corridor outside in case smoke should be accumulating there also. For this purpose, the smoke alarm in each room may have a wire or wireless connection to lighting units in the corridor.

The housing of each lighting unit preferably comprises a number of light emitting diodes, and preferably provides a minimum of one lux of illumination to the darkened area. The unit may comprise LEDs of different colours, usually with a majority of white LEDs for illumination and a smaller number of green ones, for example in the form of an arrow to indicate direction. Other colours may be used, for example red lettering by the lift to provide an illuminated warning not to use it.

The lighting unit may also incorporate a photoluminescent strip, charged by ambient light, to provide a fail-safe indication of the exit direction should the LEDs of the unit fail to illuminate for any reason.

The lighting units are required to be hard-wired to mains electricity and will also have their own independent power supply such as a lead acid battery, as a fail-safe power source.

The system of the present invention may be introduced to any existing fire detection system or a single smoke detector in a building.

The preferred embodiments of the invention will now be described with reference to the accompanying drawings wherein: Figure 1 shows schematically a corridor within a building in which a safety light system according to the invention is installed; Figure 2 shows a typical safety light unit in accordance with the invention; and Figure 3 is a circuit diagram of the unit of Figure 2.

Figure 1 of the drawings shows a corridor 10 with an exit door 12 at the far end and room doors 16 on each side.

Mounted at intervals along one wall, at a height that preferably does not exceed 500mm from floor level, are safety light units 15 in accordance with the present invention, each comprising an array of light-emitting diodes (LED5) 25, 28 as shown in Figure 2 Corridor lighting is provided by ceiling mounted units 18, between which are located smoke detectors 14.

When smoke 13, generated by a tire in one of the rooms, emerges from a door 16, it tends to rise in the corridor, obscuring the ceiling lighting.

When a smoke detector 14 detects smoke 13, it is triggered and emits a sound the volume and frequency of which, detected by sensors in the safety light units 15, causing the light emitting diodes (LED5) in them to illuminate to guide occupants towards the exit door 12.

A unit 15 in accordance with the invention is shown in Figure 2. The unit comprises a housing 20 of generally rectangular shape, adapted to be mounted on a wall as shown in Figure 1. On the front surface of the housing is a strip 22 formed with an arrow head 24 to indicate the direction of the exit. In some embodiments the strip may comprise a photoluminescent material so that the event that the ceiling lighting fails, this photo luminescent strip will remain visible.

Positioned along the front surface is a plurality of LEDs 25, 28, which may be of varying colours. Typically the LEDs 25 aligned along the strip 22 will be white, while the LEDs 28 in the arrow head may suitably be green. Referring now to Figure 3, an electrical circuit within the housing 20 of Figure 2 includes a battery 30 arranged to power an array of LEDs 25, 28, connected in parallel. A relay switch 32 normally keeps the circuit open so that the LEDs are not powered. The relay is connected to a sound sensor 35, in a relay circuit also powered by battery 30, which reacts to sound of a frequency and minimum volume associated with the smoke detectors 14, so that when a smoke detector is activated the relay circuit 38 is closed, in turn activating the relay 32 to close the LED circuit and illuminate the LEDs 25, 28.

The LEDs 25, 28 may be arranged also to be activated by other means. For example, the LED circuit could include a further relay circuit arranged to be triggered I the event of a power failure so that if the normal corridor lighting were to fail the fire safety lights 15 would be illuminated.

Claims

CLAIMS1. A wall mounted lighting unit comprising electrically-powered light sources, an electrical power circuit to illuminate said light sources and a sound sensor associated with said circuit arranged to direct power to the light sources when the sound sensor detects sound in a specific frequency range associated with a fire or smoke alarm.
2. A safety lighting unit according to claim 1 wherein the light sources comprise an array of light emitting diodes arranged to indicate an exit direction.
3. A fire safety lighting unit according to claim 2 wherein the light emitting diodes of said array are of more than one colour and are arranged in a pattern to indicate an exit direction.
4. A safety lighting unit according to claim 1 or claim 2 wherein the lighting unit has a surface pattern to indicate an exit direction
5. A fire safety lighting system comprising at least one safety lighting unit according to any one of claims 1 to 4 mounted on a wall at a height of not more than one metre above the floor level and at least one fire or smoke alarm mounted at a position remote from the lighting unit, the alarm being arranged, when activated by the presence of smoke, to emit sound at a frequency and volume detectable by the sound sensor in the lighting unit, to activate the lighting unit.