AU719440B2 - Concealed exit signage - Google Patents

Description

Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: DAVID ALAN ROBINSON Actual Inventor: DAVID ALAN ROBINSON Address for Service: MADDERNS, 1st Floor, 64 Hindmarsh Square, Adelaide, South Australia, Australia S Invention title: CONCEALED EXIT SIGNAGE Details of Associated Provisional Application No: PN 6342 dated 02/11/1995 i The following statement is a full description of this invention, including the best method of performing it known to me.

This invention relates to building emergency exit signs and in particular to an exit sign which is visible only in an emergency.

BACKGROUND

Fire and life safety engineering involves the design of work, leisure and accommodation environments which minimise the risk of loss of life and injury to those who occupy those environments.

Safe egress from those environments in the event of emergency is one of the many concerns of fire and life safety engineering. Typically, exit signs are highly visible and conspicuous in terms of their location, colour and illumination. The more visible the signage the greater the likelihood that it will provide adequate indication to occupants of a safe egress route during an emergency.

Various levels of government, legal precedent and regulation require and encourage the adoption of fire and life safety codes of practice in relation to the provision of adequate exit signage. Those codes specify and/or recommend requirements relating to exit signs and in particular preferred words or symbols, minimum word 20 or symbol sizes, acceptable colours, minimum luminosity, minimum fields of view, fail-safe actuation methods, preferred location with respect to egress location, etc.

All of the known codes of practice emphasise the visibility of an exit sign during an emergency and it has become common practice to provide an exit sign which is 25 visible and illuminated not only in the event of an emergency but also at all other 0 times. The codes also allow for the indirect illumination of exit signage as an S alternative to integral illumination.

Unfortunately the conspicuous nature of exit signs are an unavoidable blight on the aesthetics of the interior environment of a building.

It is an object of the invention to overcome or reduce the aesthetic problem while maintaining the functionality and purpose of exit signs.

BRIEF DESCRIPTION OF THE INVENTION It will be appreciated that oncethe invention has been expressed and achieved acceptance, there are many ways in which the invention may be put into practice.

In a broad aspect of the invention an exit sign apparatus comprises an exit sign which is not visible until an emergency condition exists after which said exit sign is made visible.

In an aspect of the invention the exit sign apparatus comprises an exit sign means for visualising an exit sign, said exit sign means located within a building whereby an .15 exit sign is not visible from within said building until an emergency condition exists after which said exit sign is made visible.

In a further aspect of the invention, the exit sign is projected onto a visible portion of said exit sign or onto an interior surface of said building so as to be made visible to °20 an occupant of said building when a said emergency condition exists.

In a further aspect of the invention, the exit sign means comprises an exit sign which is concealed in a cavity of a building and said exit sign is not visible to an occupant of the building until an emergency condition exists, said exit sign means further comprising actuation means arranged when in receipt of a signal representative of said emergency condition to make said exit sign visible.

In a yet further aspect of the invention, the exit sign means is arranged to conceal the exit sign from view by latching said exit sign against a force which would otherwise move said exit sign into a position visible to an occupant of said building, and when emergency condition exists said latch means is actuated by said actuation means to release said exit sign by allowing said force to act and so make said exit sign visible.

In a yet further aspect of the invention, an exit sign system for a building comprises a plurality of exit sign means for visualising an exit sign further comprising an actuation means arranged when in receipt of a signal representative of an emergency condition to make said exit sign visible, said exit sign means located within a building whereby an exit sign is not visible from within said building until a said emergency condition exists after which said exit sign is made visible adjacent a safe egress point of said building, an assessment means comprising a plurality of sensors for detecting a characteristic of the environment in the detection range of one or more of said plurality of said sensors; and one or more sensor output assessment means to determine whether an emergency condition exists based on the one or more sensor outputs and to provide an actuation signal to one or more of said exit signs to 5 indicate a safe egress point or en route to said egress point of said building.

Specific embodiments of the invention will now be described in some further detail with reference to and as illustrated in the accompanying Figures. These embodiments are illustrative, and not meant to be restrictive of the scope of the ,20 invention.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 depicts the basic elements of an emergency exit sign assembly of the invention; Fig. 2 depicts a cross-sectional view of a concealed exit sign assembly; Fig. 3 depicts a cross-sectional view of a visible exit sign assembly; Fig. 4 depicts a partial side view of some of the internal elements of an exit sign Fig. 5 depicts a side elevation of a rubber strap, clip and fixing cleat of the suspension means of an exit sign assembly; Fig. 6 depicts an end elevation of the suspension means of an exit sign; and Fig. 7 depicts a fixing means for the housing of the emergency exit sign.

Fig. 8 depicts an assembled side view of a ceiling fitted with a further embodiment of a raised and concealed exit sign assembly; Fig. 9 depicts an assembled side view of an exit sign assembly with the sign lowered into a visible position; 9* *0 9 9 o ego o Fig. 10 depicts parts of the exit sign assembly shown in Figs 8 and 9; Fig. 11 depicts an assembled side view of a wall fitted with a further embodiment of a concealed exit sign assembly; Fig. 12 depicts an assembled side view of an exit sign assembly with the sign in a visible position; Fig. 13 depicts a facia plate for an exit sign assembly of the wall mounted type shown in Figs 11 and 12; and Fig. 14 depicts parts of the exit sign assembly shown in Figs 11, 12 and 13.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION In a first embodiment an exit sign commonly referred to as a display panel preferably comprises a translucent material suitable for the transmission of visible light from its surface at an appropriate luminosity to meet the applicable code of 20 practice. Any suitable word or symbol 12 is made more visible with the assistance of the transmission of visible light through the display panel and in this embodiment ooo• preferably the word "EXIT" is marked on the display panel To the present it is typical for a display panel to be permanently affixed to a ceiling mounted bracket. The display panel is therefore visible at all times. Above the display panel but otherwise concealed is located an emergency actuated light source which illuminates the display panel making it more visible in an emergency situation. Typically the word or symbol is green or red in colour. Thus the display panel is always visible even though the light source is not actuated. Although it is not unusual for some exit signs to be continuously illuminated and therefore highly visible at all times.

In this embodiment a display panel 10 is fitted with a thin metal bracket 14 which is preferably open to allow the transmittance of visible light to the display panel through upper surface 16. The bracket may also provide a void for the placement of the light source directly above the display panel 10 and moveable with it. A power source for the light would be located elsewhere in the exit sign assembly. The bracket further comprises tabs 18 and 20 located at opposite ends of the bracket 14, the purpose of which will be described later in the specification.

A facia plate 22 is typically used to provide an aperture 24 through which in previous installations visible light would be able to enter the permanently fixed display panel 10 along its upper surface 16.

However, in this embodiment, the aperture 24 is provided to allow the display panel to exit its concealed location above the aperture when released from its raised position.

Since the facia plate 22 is the only visible element of the arrangement and its colour and material are not relevant to the operation of the apparatus, interior designers may choose the most appropriate colour, shape and material of the facia plate.

Oo *ooo Enclosure 26 is sized to house the raised display panel 10 as well as the ancillary V..o devices which activate the release of and illuminate, the display panel in the event of *an emergency.

Fig 2 depicts a side section view of the enclosure 26 located above the ceiling 28 which in this embodiment comprises plaster board or various other materials. Like elements in both Figs 1 and 2 are similarly identified.

In this embodiment, an electromagnet 30 is used to attract a metallic portion 31 of the bracket 14 so as to maintain the bracket and display panel in their raised position.

However, this is only one of many ways by which the exit signage could be retained in its raised position. For example, the electromagnet may be part of a latch mechanism which physically latches onto a portion of the bracket or display panel and thereby retains them in their raised position.

Release of the display panel occurs when a control signal is received by the latch mechanism and the latch is removed from the display panel.

As a further fail-safe feature the loss of power to the electromagnet or latch mechanism will actuate the release mechanism.

Fire alarms, bomb threats and other emergency conditions may also initiate the release function.

Preferably, guides 32 and 34 maintain the display panel 10 in a vertical orientation and ensure the display panel drops vertically when released. Preferably, the guides are made of a durable low friction material, in this embodiment nylon. The guides 32 and 34 need only guide the ends of the display panel 10 near the tabs 18 and alternatively the guides may guide side portions of both the bracket 14 and display panel 10 as required.

20 When the display panel 10 is released from its raised position it drops through the aperture 24 to become visible to occupants in its vicinity. Preferably, a bracing means is attached to each end of the display panel 10 to limit the distance it drops, which is such that the word or logo 12 on the display panel becomes visible but is not so low that the visible light source 36 cannot effectively transmit its radiated energy into the display panel 10 either directly or via the upper surface 16 of the display 0..

panel Preferably, the bracing means on the end of the display depicted in Figs 2, 3 and 4 comprises a pair of elastomeric straps 38 and 40 which in one embodiment are clipped to the bracket 14 in the manner depicted in Figs 5 and 6.

Preferably, there is an impact absorbing means 42 for absorbing some of the force resulting from the tabs 18 and 20 reaching their safe and predetermined end of travel. Preferably the impact absorbing means is a foam cushion material located on the ends of the guides. The location of the cushion material is depicted in Figs 2, 3 and most clearly in Fig 4.

Depending on how well the straps are adjusted or how well they retain their elastomeric properties at the time, the impact absorbing means may or may not be impacted every time a display panel drops into its visible position.

Fig 3 depicts a side section view of the display panel 10 in its lowered position. Like numerals used in Fig 2 depict like elements in Fig 3. An alternative luminaire 36A is shown in end elevation such that the light emitting element is fitted within the bracket 14 and moves up and down with it. The power source 35 for the light emitting element may be fitted elsewhere typically adjacent the assembly.

The straps 38 and 40 are shown fully extended and the tab 18 is positioned just above the upper surface of the impact absorbing material 42.

20 Although not clearly shown it will be apparent that the visible light source will too* 0006•illuminate almost the complete length of the display panel except where the facia *9 t plate aperture walls 44 and 45 extend above a small portion of the upper end of the display panel 25 Fig 4 provides a partial breakaway side view of the emergency signage assembly i depicting like elements of Figs 1, 2,3 and 5 with like numerals.

Fig 5 depicts a fixing arrangement for the bracing means comprising a pair of straps 38 and 40 which loop through clips 46 and 48 which themselves are attached to apertures 50 and 52 of a fixing cleat 54. The cleat is fixed in any suitable manner to the bracket 14 as shown in Fig 6 which shows a side elevational of the fixing assembly described above.

Fig 7 depicts a partial side view of exit sign housing 26 and facia plate 22 located adjacent the aperture formed in the plasterboard ceiling 28. Figs 2 and 3 show end views of the housing 26, plate 22 and ceiling 28 which clearly depicts flange 56 on one side of the housing near the top surface of the ceiling which can be arranged to provide a way to distribute the dead weight of the exit sign and the live weight when it is actuated. It is however, preferable to fix the sign to the ceiling so that the sign does not dislodge when actuated.

Clip 58 is used to join together the facia plate 22 and the housing 26. It is also preferable that the clip fixing be adjustable to accommodate different thicknesses of ceiling, thus there is provided in the housing or the clip a slotted hole through which a bolt or other fixing means 60 is placed for fixing when the appropriate clamping force on the ceiling between the housing and facia plate is reached. Preferably, a simple to operate turn fastener 62 is used to fix the clip 58 to the facia plate 22.

The embodiment described in this specification is merely illustrative of the following non exhaustive list of the preferable features of a concealed emergency exit sign arrangement.

The assembly 26 preferably minimises the ingress of dirt, dust or moisture so as to not lessen the illumination level of the exit signage when in use or adversely affect its fail-safe characteristics.

The word or symbol should be visible during an emergency and clearly communicate that a safe egress route for occupants of the environment within which the emergency signage apparatus is fitted.

The display panel may be any size and may be translucent so as to effectively transmit the enclosed light source radiation when the display panel itself is visible and the emergency actuation process turns the light source on. However, the display panel may also be reflective so that an external light source, such as an illumination device which itself may be concealed or visible, will adequately illuminate the exit sign when made visible.

The exit sign may also comprise a concealed exit sign projection device arranged to magnify and project a suitable exit word or symbol onto a suitable surface once actuated. The exit sign may also comprise an exposed sign which is latched in a position for example adjacent a ceiling or wall of the building structure but which is unlatched upon actuation to move into a more visible location. For example, the exit sign may be latched against the ceiling and upon actuation the exit signed drops to a vertical orientation into the view of the occupants of the building. The exit sign may then be illuminated in the many ways described previously. Return of the exit sign is by way of manual or automatic resetting of the latch.

As an alternative for exit signs which are not clearly visible but become so when actuated, it may be possible to reveal the word or symbol on the sign only during an emergency situation. One example of this approach is to use a display mechanism which transforms a non-descript pattern into an exit word or symbol when actuated.

A further example of this approach is to use a display mechanism which removes a 9o•• cover means to reveal the exit word or symbol even though the frame carrying the sign does not move.

The exit sign assembly may preferably be provided with a test facility independent of the emergency actuation arrangement. It is also preferable that the exit sign once test actuated be capable of being reset (manually or automatically) into its concealed location.

9..

The visible light source should preferably be independently powered and operable by an emergency actuation signal or a test actuation signal. The period of illumination provided by the visible light source may be any predetermined period in accordance with conditions or applicable codes.

Release mechanisms should preferably be fail-safe.

The force or means to move the exit sign from its concealed location which may involve sideways, upwards or downwards movement may be assisted by way of use of gravity, a bias means, or hydraulic/ pneumatic means, etc.

The emergency exit signage may preferably be reset manually but it may also be reset automatically to its concealed position if the emergency is not sustained over a predetermined time or commanded by the person in control via the emergency actuation system and its available signalling modes.

A detailed description of a further embodiment of the invention which swings rather than drops the exit sign into a visible position is provided below and depicted in Figs 8, 9 and Figs 8 and 9 depict a side view of a base support plate 64 of an emergency exit sign assembly which is preferably of a size suitable for insertion within a standard modular ceiling grid system as a complete unit. The base support unit is preferably constructed of MDF board or other suitable material with sufficient rigidity and strength to support the dead and active load of the exit sign assembly as well as 20 having a suitably aesthetic externally visible surface finish.

Incorporated within the base plate 64 is a display panel 66 typically comprising a 0: °i translucent material, suitable for the transmission of visible light from its surface at °an appropriate luminosity to meet applicable codes of practice.

A suitable word or symbol located on the panel 66 is made more visible with the assistance of the transmission of visible light through the display panel and in this embodiment preferably the word "EXIT" is marked on the display panel 66. The word or symbol 68, as shown in Figure 10, may be marked on either side of the display panel 66 but if one side is not so marked, it will have an overall colour or surface finish which matches the base plate 64 so as to provide aesthetic consistency with the ceiling features. However, the display panel 66 may also be reflective on any side so that an external light source, such as an illumination device which itself may be concealed or visible, will adequately illuminate the exit sign when made visible.

Attached to the display panel 66 at a point or along a portion of its lower edge is a metallic portion 69 which is attracted by an electromagnet 70 so as to maintain the display panel 66 in a substantially concealed horizontal position. The electromagnet is attached to a suitable bracket 72 which provides the necessary support and clearance so as to align the display panel 66 within the opening of the base support plate 64. As an alternative the assembly may be mounted vertically in a wall such that actuation of the signage presents the panel 66 external of the wall where it can be easily seen.

Attached to and fitted over the display panel 66 on the top inner surface (ie above the ceiling grid system) of the base support plate 64, is a lightweight cover and bridging plate 73 which acts as a dust protective shield for the display panel 66 when in its S" horizontal normal (concealed and suspended) state; and a bridging fixing plate is also located over the hinged edge of the display panel 66 to add support/fixing for the light pack 74. The light pack 74 and battery pack 76 may be known fixtures with the light pack 74 being typically attached to the bridging plate 73 to allow for the light source to effectively and directly transmit its radiated energy into the display panel 66, via the upper edge 77, of the display panel 66, as shown in Fig 9, after it has been moved into the visible position.

The slot 78 within the bridging plate 73 allows passage, external of the assembly, of 25 the light source in the light pack in an emergency and also, where the light source is continuously illuminated, provides a means for visually checking the light source operation at any given time.

The display panel 66 is provided with a means to allow for rotation from the horizontal (concealed) position to the vertical (visible) position. In this embodiment a pivot means is preferably of the form of a hinge pin 80 and socket 82. The socket 82 may be a recessed collar or tube fixed within the two sides of the display panel 66.

The pin 80 is located in the base support panel 64 and is sized so as to engage a respective socket 82 within the display panel 66.

Release of the display panel 66 to a visible position occurs when a control signal is received by the electromagnet 70 which de-energises its attractive force to allow the display panel 66 to fall under the influence of gravity to the vertical position in to full view along with the activation of the light source 74 which illuminates the display panel to clearly indicate the approved egress route during an emergency.

The exit sign assembly may preferably be provided with an indicator 86, as depicted in Fig 10, to show that electrical power is available to the light and battery pack 74 and 76. A test actuation button 84 is also shown on the external surface of the base support plate 64.

It is also preferable that the exit sign, be tested and once test actuated, be capable of being reset (manually or automatically) into its concealed position if the emergency is not sustained over a predetermined time or commanded to be reset by a person in control of the emergency actuation system and its available signalling modes. The period of illumination provided by the visible light source may be any 20 predetermined period in accordance with conditions or applicable codes. Release mechanisms should preferably be fail-safe.

"i A detailed description of a yet further embodiment of the invention which moves sideways into view out of a wall cavity or similar is provided below and depicted in Figs 11, 12, 13 and 14.

An enclosure 88 containing the emergency exit sign assembly comprises preferably an enclosure which minimises the ingress of dirt, dust or moisture so as to not lessen the illumination level of the exit signage when in use or affect its fail-safe characteristics.

Incorporated within the enclosure 88 is the display panel 90 comprising in this embodiment a translucent material suitable for the transmission of visible light from its surface at an appropriate luminosity to meet the applicable code of practice.

A suitable word or symbol 92 is made more visible with the assistance of the transmission of visible light through the display panel 90 and, in this embodiment preferably the word "EXIT" is marked on the display panel 90. This word or symbol 92 may be marked on either side or both sides of the display panel 90. However, the display panel 90 may also be reflective, so that an external light source, such as an illumination device which itself may be concealed or visible, will adequately illuminate the display panel 90 when made visible.

Attached to the display panel 90 at its rear is a bracket or enclosure 94 which incorporates a void for the placement of the light source 64 directly behind the rear edge of the display panel 90 and moveable with it. Power for the light source could alternatively be located elsewhere remotely from the enclosure 88 or attached to it, accessible from the opening in the building structure.

Mounted within the enclosure 88 and adjacent the end plate thereof is an electromagnet 96 used to attract a metallic portion 98 located on the bracket or enclosure 94. While the electromagnet is energised the display panel is maintained in a retracted (concealed) position. Release of the display panel 90 occurs when a control signal is received by the electromagnet 96 which de-energises its attractive S force which then allows the display panel 90 to exit (become visible) through the 25 aperture 104 of the facia plate 106 as shown in Fig 12.

.t.ooi In this embodiment, a single spring 108 contracts in length when the electromagnet de-energises its attractive force, to provide the means to move the display panel through the aperture 104 from its concealed position. Alternatively, means to move the display panel 88 from its concealed location may be assisted by a bias means such as for example an active hydraulic/pneumatic means however any suitable bias means would suffice.

To allow the display panel 90 to be released in a controlled and aligned manner, a top guide 110 is used, comprising a metal guide with inner slide frame and nylon wheels 111. The bottom guide 112 may comprise a channel of PVC material.

However, there are various channel or guide means suitable for this task, therefore the embodiment described is merely illustrative of a preferable arrangement for this embodiment of an emergency exit sign release assembly.

A facia plate 106 is used to provide an aperture 104 through which in previous installations visible light will be able to enter the permanently fixed display panel along its surface trailing edge. Since the facia plate 106 is the only visible element of the arrangement and its colour and material are not relevant to the operation of the apparatus, interior designers may freely choose the colour, shape and material of the facia plate. The facia plate of the embodiment may have the word "EXIT" 107 or an alternative symbol marked on it, as shown in Figure 13, to assist in identifying the S• nature of the concealed assembly to service engineers or building inspectors.

Furthermore the facia plate 106 may preferably be provided with a test facility actuator 114 and indicator 116 as shown in Figure 13, to show that electrical power is available to charge the battery pack. It is also preferable that the exit sign, once test actuated, be capable of being reset (manually or automatically) into its concealed position. The period of illumination provided by the visible light source may be any predetermined period in accordance with conditions or applicable codes. Release •mechanisms should preferably be fail-safe.

Fig 14 depicts a perspective view of the enclosure 88 of Figs 11 and 12.

The emergency exit sign assembly of this embodiment like all the previously described embodiments may preferably be reset manually but it may also be reset automatically to its concealed position if the emergency is not sustained over a predetermined time or commanded to be reset by a person in control of the emergency actuation system and its available signalling modes.

It is typical to have all the exit signs visible to direct persons to all the predetermined egress points. However, every egress point is not necessarily a safe egress point in every emergency. It is therefore possible and advantageous to provide visible exit signage in accord with the invention during an emergency only at selected locations which will provide the safest egress route. This is possible using a plurality of sensors (smoke, gas, chemical, temperature, etc) located throughout a building or environment to determine the extent and condition of the emergency, so that a computer based automatic assessment means determines which of the predetermined egress points is safe. The assessment means using the available signalling mode is then capable of actuating selected, otherwise concealed, exit signs to provide a visible indication of the safest egress route and egress points.

In a quickly changing emergency situation it may also be advantageous to rely on the ability of the computer based automatic assessment means to continually assess the *extent and condition of the emergency and provide if necessary signals to make the exit signs no longer visible and actuate others, thereby providing an appropriate egress route according to the emergency condition.

Thus, not only are the aesthetics of an environment catered for, the emergency exit signage becomes visible in accordance with the dynamics of the emergency.

It will be appreciated by those skilled in the art, that the invention is not restricted in its use to the particular application described and neither is the present invention 25 restricted in its preferred embodiment with regard to the particular elements and! or

OOO:

Sfeatures described herein. It will be appreciated that various modifications can be made without departing from the principles of the invention, therefore, the invention should be understood to include all such modifications within its scope.

Claims (14)

1. An exit sign apparatus comprising an exit sign means wherein said exit sign means comprises an exit sign which is concealed in a cavity of a building and said exit sign is not visible to an occupant of the building until an emergency condition exists, said exit sign means further comprising actuation means arranged when in receipt of a signal representative of said emergency condition to make said exit sign visible.

2. An exit sign apparatus according to claim I wherein said exit sign is movable and comprises exit indicia, said exit sign located in a first position which conceals said indicia and locatable in a second position which reveals said indicia.

3. An exit sign apparatus according to claim I wherein said exit sign means is arranged to conceal an exit sign from view by latching said exit sign against a force S: which would otherwise move said exit sign into a position visible to an occupant of S" said building, and when an emergency condition exists said latch means is actuated by said actuation means to release said exit sign by allowing said force to act and so make said exit sign visible.

4. An exit sign apparatus according to claim 3 wherein said exit sign comprises a metallic portion and latched in a concealed location by the action of an electromagnetic force energised from a non-emergency power source which attracts said metallic portion of said exit sign and which is de-energised by said actuation 0.25 means in an emergency condition whereupon said exit sign is acted upon by gravity to move into a position visible to an occupant of said building.

An exit sign apparatus according to claim 3 wherein said exit sign comprises a metallic portion and latched in a concealed location by the action of an electromagnetic force energised from a non-emergency power source which attracts id metallic portion of said exit sign and which is de-energised by said actuation X TE4 17 means in an emergency condition whereupon said exit sign is acted upon by a force exertion means to move into a position visible to an occupant of said building.

6. An exit sign apparatus according to claim 3 wherein said force is exerted by a two ended elastomeric means attached at one end to said exit sign and at said other end anchored relative to said building so as to be within the elastic boundaries of said elastomeric means and so provide said force.

7. An exit sign apparatus according to claims 1, 2, 3, 4, 5 or 6 wherein said exit sign is translucent and said exit sign apparatus further comprises an emergency power source and illumination means powered from said emergency power source arranged so that when an emergency condition exists said exit sign is illuminated by said illumination means. *15

8. An exit sign apparatus according to claims 1, 2, 3, 4, 5 or 6 wherein said exit sign is illuminated after being released. *o

9. An exit sign apparatus according to claim 1, 2, 3,4, 5 or 6 wherein said exit sign is reflective and illuminated after becoming visible to an occupant of said 20 building. S

10. An exit sign apparatus according to claim I wherein said exit sign means comprises an opaque cover means operable to conceal or not conceal said exit sign from an occupant of said building when there is no or an emergency condition respectively.

11. An exit sign system for a building comprising a plurality of exit sign means for visualising an exit sign further comprising an actuation means arranged when in receipt of a signal representative of an emergency condition to make said exit sign visible, said exit sign means located within a building whereby an exit sign is not visible from within said building until a said emergency condition exists after which said exit sign is made visible adjacent a safe egress point of said building, a plurality of sensors for detecting a characteristic of the environment in the detection range of one or more of said plurality of said sensors; and one or more sensor output assessment means to determidne whether an emergency condition exists based on the one or more sensor outputs and to provide an actuation signal to one or more of said exit signs to indicate a safe egress point of said building.

12. An exit sign apparatus substantially as hereinbefore described and illustrated in the accompanying figures 1 to 6.

13. An exit sign apparatus substantially as hereinbefore described and illustrated in the accompanying figures 8 to

14. An exit sign apparatus substantially as hereinbefore described and illustrated in the accompanying figures 11 to 12. 000.0, DATED this 6th day of March 2000 DAVID ALAN ROBINSON By his Patent Attorneys MADDERNS KNTi 19