WO1998012692A1 - Signs and lightning systems - Google Patents

Abstract

A sign (1) contains a plurality of self-powered light-emitting elements (5) (e.g. of tritium) which are juxtaposed to form the shape of at least one symbol (e.g. an arrow) and are contained within a housing that is adapted to be floor-mounted or mounted in a wall or the like at low-level. The elements (5) are mounted in base (2) which is sealed to a transparent lid (3) in a gas-tight manner. The base (2) and lid (3) are in turn mounted in an outer box (10) which is secured to a floor (17) to contain the sign (1) therein, substantially flush with the surface of the floor (17). The sign (1) may be used with advantage as an emergency sign or direction system at floor or low level, and does not require an electricity supply. Also disclosed is a lighting system comprising elements (5) mounted within a tube which is in turn engaged within an aluminium profile provided along its length with a recess through which the elements are visible (Figures 3 to 5).

Description

SIGNS AND LIGHTING SYSTEMS

This invention relates to signs and lighting systems, and is concerned particularly although not exclusively with illuminated signs and directional indicators for emergency use.

At the present time, there are many requirements for illuminated signs and directional indicators for emergency use, both in buildings and other enclosed spaces. By far the greatest proportion of these are powered by an external energy source such as mains electricity, local battery power or distant battery power. In order to use a mains supply or distant battery power, electrical cables need to be laid to the signs and indicators and the necessary electrical connections need to be made, all of which involves time and expense. In practice, little regular maintenance is given to emergency signs and lighting systems to provide indicators in most buildings, with the result that wiring faults can go undetected, thereby rendering the emergency signs and indicators useless. Where local batteries are provided, this usually entails a significant space requirement, which can be very disadvantageous where discreet installation is required. Batteries are not always regularly checked in many buildings and, when discarded by conventional methods, can add to toxic pollution of the land, thereby causing a danger to the environment.

One of the most effective positions to place emergency lighting is at floor level or low level since, in the event of a fire, smoke quickly rises to obscure lights at a higher level. However, in most buildings, the installation of floor level or low-level lighting with hard wiring is not cost effective. Self-powered light emitting elements are known, which require no external energy source to obtain illumination - for example, the product manufactured and/or sold under the registered trade mark BETALIGHT by the company Saunders-Roe Limited. These elements comprise boro-silicate glass capsules which are internally coated with a phosphor and are filled with tritium gas which activates the phosphor to produce light. It has been proposed to use such elements as a back-light source for an otherwise conventional emergency sign. Such a sign comprises a box of which the front face is partially opaque and partially translucent, to define a conventional sign - for example, in the manner of a stencil. The box contains several parallel elements which provide the back-light source, which is then visible through the stencil on the front face of the sign in suitably dark conditions.

Although such signs have the advantage of requiring no external energy source, they are not particularly efficient in the use of the light generated, and are not generally suitable for installation at low level - particularly, in a floor.

Preferred embodiments of the present invention aim to provide emergency signs and indicators which may be improved in the foregoing respects.

According to one aspect of the present invention, there is provided a sign comprising a plurality of self-powered light-emitting elements which are juxtaposed to form the shape of at least one symbol and are contained within a housing that is adapted to be floor-mounted or mounted in a wall or the like at low-level. Preferably, the housing comprises a base in which said elements are located and a transparent or translucent cover which covers said base and elements.

Preferably, said base is formed with at least one recess in which said elements are located.

Preferably, said cover comprises a polycarbonate plastics material.

Preferably, said housing is sealed in a substantially gas-tight manner.

Preferably, said housing further comprises an outer mounting box in which all other components of the sign are mounted.

Preferably, said box is of metal.

Preferably, said box is provided with means for securing the box to a floor.

Preferably, said box is formed with a collar to engage around a corresponding recess provided in a surface of a floor, wall or the like.

Preferably, said elements are substantially straight.

Said symbol may be an arrow. Preferably, each said element comprises a tube containing a fluorescent material and a radioactive gas which causes said material to fluoresce.

Preferably, each said tube is of glass and said fluorescent material is a phosphor.

Preferably, said gas is tritium.

A sign as above may be of substantially circular shape in plan view.

According to another aspect of the present invention, there is provided a lighting system comprising a plurality of signs according to any of the preceding aspects of the invention, each of which is floor-mounted or mounted at a low-level in a wall or the like so as to be substantially flush with the floor or wall surface.

According to a further aspect of the present invention, there is provided a sign comprising: at least one self-powered light-emitting element arranged to form the shape of at least one symbol; a base in which the or each said element is located; a transparent or translucent cover which covers said base and elements; and a box formed with an aperture: wherein said base and cover are mounted in said box, with the or each said element located in said base, said cover secured firmly to said base, and the or each said symbol visible through said cover and said aperture.

Preferably, said box is adapted to be flush-fitted in a corresponding recess formed in the surface of a supporting floor, wall or the like.

A sign as above may further comprise any one or more of the features disclosed in the accompanying specification, claims, abstract and/or drawings, in any combination.

According to another aspect of the present invention, there is provided a lighting system comprising: a. an elongate profile formed with an elongate recess which is open at one side of the profile; b. a tube engaged within said recess; and c. a series of self-powered light-emitting elements engaged within the tube so as to be at least partly visible along said recess.

Preferably, said tube and recess are so shaped as to inhibit rotation of said tube within said recess.

Preferably, said recess and said tube are respectively of substantially C-shaped and D-shaped cross-section, and said profile is provided with ribs which project into said recess to engage with corresponding grooves formed on said tube.

Preferably, said elements are of substantially circular cross-section. A lighting system as above may further comprise a carrier in which said elements engage, and which engages within said tube.

Preferably, said elements snap-engage said carrier.

A lighting system as above may further comprise reflection means for reflecting light emitted by said elements in a direction in which said elements are visible along said recess.

Preferably, at least a visible portion of the tube is provided with an anti-scratch surface.

Preferably, said profile is of metal.

Preferably, said profile and/or tube and/or carrier is extruded.

Preferably, said profile is adapted to accommodate an edge of carpet or floor covering.

Preferably, said profile is adapted to be fitted to an emergency push bar.

Preferably, each said element comprises a tube containing a fluorescent material and a radioactive gas which causes said material to fluoresce.

According to a further aspect of the present invention, there is provided a method of installing an emergency indicating system in a building, comprising the steps of securing a lighting system according to any of the preceding aspects of the invention, to a part of the building or a fixture within the building.

In the context of this specification, the term "self-powered light- emitting element" means an element that emits light without the consumption of external energy (such as a battery, mains power etc), and includes self-fluorescing elements in which phosphors (which may be coloured) are activated by a radioactive gas (eg tritium).

In the context of this specification, the term "symbol" includes alphanumeric characters and any other symbol which conveys a meaning to a human observer.

In the context of this specification, the term "low-level" means a level at or below 1 metre from floor level, and preferably a level at or below 50 cm or 30 cm from floor level.

In the context of this specification, the term "fixture" means an item that is fixed relative to the building, but includes items that have moveable parts, such as doors, windows, etc.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which: Figure 1 is a perspective exploded view of one example of a sign according to one embodiment of the invention;

Figure 2 is a sectional view of a floor-mounted box for the sign of Figure 1;

Figure 3 is a sectional view of one example of a lighting system according to another embodiment of the invention;

Figure 4 is a perspective exploded view of the lighting system of

Figure 3;

Figure 5 shows in section various components of the lighting system of Figures 3 and 4;

Figures 6 to 8 are perspective views of an end cap and connectors for use with the lighting system of Figures 3 to 5;

Figure 9 is a perspective view of an alternative profile for use in a lighting system generally as shown in Figures 3 to 5;

Figures 10a to lOg show in section various alternative profiles for use in a lighting system generally as shown in Figures 3 to 5, together with component parts for use with such profiles;

Figures lla to lie show in section a profile for use on a stair, in a lighting system generally as shown in Figures 3 to 5, together with component parts for use with such a profile; and Figure 12 is a perspective exploded view of an alterative profile for use with an emergency push-bar, in a variation of the lighting system shown generally in Figures 3 to 5.

In the figures, like reference numerals denote like or corresponding parts.

The sign 1 that is shown in Figure 1 comprises a housing having a base 2 and a translucent or transparent lid 3, either or both of which may be of polycarbonate plastics material. The base 2 is formed with three recesses 4, in each of which a respective luminous tube 5 is housed. As may be seen in Figure 1, the three recesses 4 are juxtaposed to form the shape of a symbol which, in this example, is an arrow. The three luminous tubes 5 are therefore also juxtaposed in the same arrow shape. In this example, both the recesses 4 and the tubes 5 are substantially straight.

Each of the tubes 5 is of glass which is internally coated with a fluorescent phosphor material, and contains a radioactive gas (eg tritium) which causes the phosphorous material to fluoresce. Thus, each of the luminous tubes 5 provides an element that continually emits light (or radiation, typically measured in units of lamberts) which, although of a relatively low level in daylight, is highly visible in the dark or low ambient light conditions. An outer or inner portion of each tube 5 may be painted with a reflective material, such as bright white or silver, in order to reflect all of the light emitted by the tube 5 generally upwardly through the portion of the tube 5 that is visible in use. Since the luminous tubes 5 directly make up the arrow themselves, substantially all of the light emitted by the tubes 5 is used efficiently.

In this example, the arrow symbol is made up of substantially straight tubes 5. Thus, each tube 5 may be of high strength. Any desired symbols may be made up from juxtaposition of the tubes 5, in other examples.

In the interests of robustness and safety, the clear plastics lid 3 is preferably secured to the plastic base 2 in a substantially gas-tight manner, to render the housing itself substantially gas-tight. To this end, an O-ring seal may be provided between the base 2 and lid 3.

The sign 1 is preferably enclosed within a mounting box 10 that is shown in Figure 2. The mounting box 10 is of substantially circular cross- section, having an internal recess 11 of such a size and shape as to receive the sign 1 as a snug fit. An annular collar 12 with circular aperture 16 is removably secured to a base 13 by means of fastening elements 14, which pass through the collar 12 and a facing rim of the base 13. The base 13 is secured within a suitable recess 18, eg of circular cross-section, formed in the floor 17, by means of a suitable securing means 15 such as, for example, screws, bolts or an adhesive. The fastening elements 14 may also take any suitable form, such as screw, bolts, etc. In a preferred arrangement, they comprise bolts having heads formed with hexagonal recesses in which an Allen key may engage to turn the bolts to secure or free them. The base of each recess in the bolt head may be formed with a protrusion which engages a recess formed in a suitably-modified Allen key, in order to render the fastening elements 14 substantially tamper-proof. The top of the clear plastics lid 3 of the sign 1 is preferably substantially flush with the upper surface of the collar 12 and to this end, projects into the central circular aperture 16 defined by the collar 12. The upper surface at least of the clear plastics lid 3 may be textured to provide a non-slip finish - eg by means of an acid-etch process. The upper surface of the lid 3 may be somewhat domed upwardly, in order to shed any water or liquid that might be accidentally dropped on it.

The collar has a chamfered rim 19 which tapers downwardly to the upper surface of the floor 17. As the collar 12 is relatively flat, in the manner of a thin securing plate, both the collar 12 and the upper surface of the lid 3 project above the surface of the floor 17 by only a small amount and, in the context of this specification, such an arrangement is included within the term "flush-mounted", as of the sign 1 with respect to the floor 17.

Preferably, the mounting box 10 is of a strong material such as, for example, stainless steel. A crush seal may be mounted on the stepped annular portion 6 around the lid 3, and the collar 12 of the box 13 appropriately modified in shape.

As an alterative or additional feature, the outer cylindrical surface of the base 13 and/or rim 16 is formed with an external screwthread 9 to screwthreadly engage a recess in the floor 17, thereby to secure the box 10 in the floor 17. The screwthread 9 may engage the floor 17 directly and, if the floor 17 is of a suitable material (eg wood, chipboard, etc), the screwthread 9 may cut a corresponding thread directly in the floor. Alternatively, an internally screwthreaded outer fixing member may be firstly installed in the recess 18 in the floor 17, and the box 13 subsequently screwthreadedly engaged with the fixing member by means of the screwthread 9.

The sign 1, preferably in its box 10, may alteratively be fitted in a wall (or skirting board) in a low-level position - that is, a level at or below 1 metre from floor level, and preferably a level at or below 50 cm or 30 cm from floor level.

The sign 1 and box 10 may of any suitable material. The box 10 preferably gives substantial strength to the overall assembly of sign 1 and box 10. The sign 1 and box 10 may be of rather less depth than shown in the diagrammatic representations of Figures 1 and 2. It will be appreciated that, after a specified safe service life (typically several years), the sign 1 and box 10 may readily be disassembled to facilitate recycling and/or disposal of all parts, particularly the tritium tubes 5.

The lighting system 20 that is shown in Figures 3 to 5 comprises an extruded aluminium profile 21 having side arms 22 symmetrically disposed at either side of a central recess 23 from which there depends a central web or rib 24 which is formed at intervals with apertures 25 to receiving fixing screws or the like. The lower faces (as seen) of the arms 22 and the web 24 are substantially co-planar, such that the profile 21 is suitable to be secured to a floor or other flat surface. In cross-section, the central recess 23 is substantially C-shaped, with a flattened base 26. At the inward end of each of the arms 22 there is formed a respective rib 27. A translucent or transparent elongate tube 30 is engaged within the central recess 23. In cross-section, the tube 30 is of substantially D-section and is formed with two elongate grooves 31, each of which is shaped to receive a respective one of the ribs 27 on the arms 22 of the profile 21. Only a short length of the tube 30 is shown in Figure 4.

A carrier 35 has a substantially flat base 36 and a pair of symmetrical side arms 37, and the outer surface of the base 36 and side arms 37 is of such a size and shape as to conform closely to the inside surface of the hollow tube 30 at the base 32 thereof. Thus, the carrier 35 is adapted to slide into the tube 30, such that the base 36 of the carrier 35 closely engages the base 32 of the tube 30. Because of the close fit of the two parts, the carrier 35 is inhibited from rotating within the tube 30.

Referring in particular to Figure 5, a series of luminous tubes 5 snap- engage within the carrier 35. To this end, the carrier 35 is preferably of a resilient plastics material. Each of the tubes 5 is of substantially circular cross-section, such that, when engaged within the carrier 35, the arms 37 thereof are displaced outwardly against the resilient bias, to engage the tube 5 in a secure fashion. Although only one tube 5 is shown in Figure 5, it is to be appreciated that any desired number of individual luminous tubes 5 is arranged in series along the carrier 35.

As in the preceding embodiment, each of the tubes 5 may be of glass which is internally coated with a fluorescent phosphor material, and contains a radioactive gas (eg tritium) which causes the phosphorous material to fluoresce. Thus, each of the luminous tubes 5 continuously emits light or radiation, typically measured in units of lamberts, which, although of a relatively low level in daylight, is highly visible in the dark or low ambient light conditions.

As may be seen in Figure 5, that part of each tube 5 that is visible, when the tube 5 is mounted in the tube 35, is the sector defined by the angle θ which, in this example, is approximately ninety degrees. To achieve maximum light efficiency, that outer portion (or inner portion) of the tube 5 which is below the indicated sector defined by the included angle θ is painted with a reflective material, such as bright white or silver, in order to reflect all of the light emitted by the tube 5 upwardly through the visible sector. Alternatively or additionally, the inner surface of the carrier 35 may be so coated as to reflect the light 5 upwardly through the visible sector.

In the left-hand and centre portions of Figure 5, the tube 30 is indicated simply by its internal cross-section. The full cross-section of the tube is shown in the right-hand portion of Figure 5. Here, the visible light sector defined by the included angle θ is again shown in dotted lines, and it may be seen that this corresponds to that part 33 of the tube 30 which is between the opposing grooves 31, with which the ribs 27 on the profile engage. Thus, this part 33 of the tube 30 may be conveniently formed as a lens, in order to focus or diffuse light from the tubes 5 in any desired manner. The surface of the part 33 is preferably provided with an anti- scratch finish, and/or may be textured to diffuse light from the tubes 5.

By way of example, the tube 30 may conveniently be made of polycarbonate plastics material, and may have a degree of natural resilience. The carrier 35 may also be of polycarbonate plastics material. The profile may of any suitable metal or other strong material. It is to be appreciated that all of the components of the illustrated lighting system may be made of any suitable materials.

The lighting system illustrated in Figures 3 to 5 may be assembled in a ready and convenient manner. Firstly, the profile 21 is secured to the floor (or other flat surface - eg at a low-level), by means of screws, bolts or other suitable fixings passing through the fixing apertures 25. The luminous tubes 5 are then snap-fitted into the carrier 35 at desired intervals. To this end, the carrier 35 may be formed with depressions, markings or the like to define or indicate locating positions for the tubes 5. The carrier 35 with tubes 5 in position is then slid into the tube 30, and this sub-assembly is then slid into the recess 23 formed in the profile 21.

To remove the lighting assembly, the tube 30 is simply slid out of the recess 23, whereupon the profile 21 may then be removed. The carrier 35 may then be slid out of the tube 30 and the tubes 5 removed from the carrier 35, by lifting them up against the resilient force of the arms 37.

In this way, virtually all parts of the lighting assembly 20 may readily by recycled and, in particular, tubes 5 that have served their useful life can be disposed of or recycled in a safe manner. In a variation of the profile 21, apertures for fixing screws or the like may be provided at alternative points in the arms 22, so that the whole light assembly 20 may be fitted and removed with the tube 30, carrier 35 and tubes 5 in place.

Figure 6 shows an end cap 40 for the profile 21, having projections 41 which are designed as a close friction fit within respective recesses 28 in the profile 21. An exterior surface 42 of the end-cap 40 is designed to match a corresponding pattern on the profile 21 and light-visible portion 33 of the tube 30.

Figure 7 shows a joining piece 44 which comprises a section of profile generally similar to the profile 21, but provided with opposing projections 41 to engage in respective recesses 28 in two adjacent sections of profile 21. Figure 8 shows another connector 46 which is similar in function to the connector 44, but defines a right angle to join two sections of profile 21 together, extending perpendicular to one another. It is to be appreciated that other connectors similar to the connectors 44, 46 may be provided, to provide connections at any desired angles. Also, although the illustrated profile 21 is straight, which is suitable for a wide range of applications, it is possible to provide a profile of a curved or other shape if required.

Figure 9 shows a profile 48 of different cross-section to the profile 21.

It has two side arms 49 having outer faces 47 which are at right-angles to one another. Thus, the profile 48 is suitable for fixing at a position where, for example, a floor and wall join one another - eg along a skirting board. The profile 48 may also extend vertically between two walls. In other respects, the profile 48 combines with a tube 30, carrier 35 and tubes 5 to form a lighting assembly which functions in generally the same way as the lighting assembly 20.

Figures 10a to lOg show alternative profiles for use in a lighting system generally similar to a lighting system 20 of the preceding embodiments. Thus, in each case, a tube 30 containing carrier 35 and tubes

5 (not shown) is located in a recess 23 - a more detailed description of this assembly need not be repeated here. In Figure 10a, a profile 51 has symmetrical side arms 52, each provided with a serrated upper surface 53 and terminating in a downwardly extending rib 54. In use, the profile 51 is secured to a floor (or wall) by fixing screws or the like which pass through fixing apertures 25 in central web 24, and through corresponding apertures provided in a central fastening piece 55 having a central groove 56 in which the web 24 of the profile 51 engages. The fastening piece 55 has symmetrical arms each provided with upwardly facing serrations 57 which, in use, are located under the respective arms 52 of the profile 51. Thus, an edge of a carpet can be gripped between each arm 52 and the central fastening piece 55 below it, with the rib 54 and serrations 57 engaging the carpet firmly. Thus, the profile 51 of 10a is useful for positioning between two portions of carpet.

The profile 61 of Figure 10b has one side arm 52 which is similar to that of Figure 10a, and cooperates with a handed fastening piece 65 as shown in Figure lOg. However, in Figure lOg, the other arm 62 of the profile 61 extends down to floor level and is provided with serrations 53 or alternative grip surface. It will thus be appreciated that the profile 61 of Figure 10b is suitable for use along an edge of a carpet which is to terminate, and for plain floor covering at the other side.

The profile 71 shown in Figure 10c is similar to the profile 61 of 10b, in providing a carpet fixing arm 52 at one side. However, the other arm 72 of the profile 71 is shaped to abut against an adjacent vertical wall, such that the profile 71 is suitable for fitting between an edge of a carpet and a wall or skirting board. The profile 81 that is shown in Figure lOd has two arms 62 similar to the right-hand arm of the profile 61 of Figure 10b. It will thus be appreciated that the profile 81 is suitable for fixing to a floor with a plain floor covering, where carpet is provided at neither side.

Figure lOe shows an end piece 85 which is used to close the tube 30, and is suitable for use with all illustrated embodiments with tube(s) 30.

The profile 91 that is shown in Figure lla is designed for use on a stair. It is formed with two elongate recesses 23 in each of which a respective tube 30 engages, with respective carriers 35 and luminous tubes 5, a detailed description of which need not be repeated again here.

Fixing screws or the like pass through fixing apertures 25 in a web 24 which engages with a fastening piece 65 as shown in Figure lib, to grip carpet on a riser of the stair between rib 54 and tread 57 - similar to the carpet-engaging profiles of Figures 10a to 10c. If there is no carpet on the riser, an alternative fastening piece 101 is used, having an arm 102 provided with a groove 103 to receive rib 54, and thereby continue the serrations or other pattern or tread 53 provided on the arm of 92.

A central part 93 of the profile 91 joins the riser part with a tread part, in which an upper one of the tubes 30 is engaged in its elongate recess 23, in a manner already described. Adjacent the upper tube 30 and recess 23 there is provided a larger recess 94, within which a non-slip mat or strip (not shown) may be engaged. A central rib 95 within the recess 94 is provided with fixing apertures 98 through which fixing screws or alternative securing means may pass to fasten the profile 91 to the tread of the stair. At the right hand side of the profile 91 (as seen) an end portion 96 is provided with an undercut 97, to receive a carpet or other floor covering on the stair, if provided. If such a carpet or other floor covering is not provided, an infill piece 99 is provided to engage in the undercut 97, with engaging dovetail means as shown, and thereby continue the serrated (or alternative pattern or tread) surface of the end portion 96 down to the surface of the stair tread. An end cap 85 for the tubes 30 is again shown in Figure lid.

In Figure 12, an alternative profile 110 is adapted for use with an emergency push-bar, of the type that is in common use in emergency exits in public buildings and elsewhere. To this end, the profile 110 is formed with an internal recess 111, which is adapted to receive a push-bar of an emergency exit locking system. In a lower portion of the profile 110, there are formed two elongate recesses 23, each of which receives a respective tube 30 which, as in preceding embodiments, contains carriers 35 and luminous tubes 5. End caps 112 engage respective ends of the profile 110.

In this way, both signs such as the sign 1 of Figures 1 and 2 and lighting systems as shown in Figures 3 to 12 may be used to provide an emergency lighting and/or directional system which requires no external energy source and which can be used both in buildings and other enclosed spaces, as well as extending outside such buildings and enclosed spaces.

In all embodiments of the invention, a respective bar code or other machine-readable code may be advantageously provided within each sign or lighting section, preferably built in during manufacture, to denote uniquely each sign or lighting section. Periodic scanning of such codes by an automated reader and processor may then indicate any signs or lighting sections requiring renewal - eg after a specified service life, which may typically be of the order of ten years.

In this specification, terms of absolute orientation are used conveniently to denote the usual orientation of items in normal use and/or as shown in the accompanying drawings. However, such items could be disposed in other orientations, and in the context of this specification, terms of absolute orientation, such as "top", "bottom", "left", "right", "vertical" or "horizontal", etc. are to be construed accordingly, to include such alternative orientations.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A sign comprising a plurality of self-powered light-emitting elements which are juxtaposed to form the shape of at least one symbol and are contained within a housing that is adapted to be floor-mounted or mounted in a wall or the like at low-level.

2. A sign according to claim 1, wherein the housing comprises a base in which said elements are located and a transparent or translucent cover which covers said base and elements.

3. A sign according to claim 2, wherein said base is formed with at least one recess in which said elements are located.

4. A sign according to claim 2 or 3, wherein said cover comprises a polycarbonate plastics material.

5. A sign according to claim 2, 3 or 4, wherein said housing is sealed in a substantially gas-tight manner.

6. A sign according to claim 2, 3, 4 or 5, wherein said housing further comprises an outer mounting box in which all other components of the sign are mounted.

7. A sign according to claim 6, wherein said box is of metal.

8. A sign according to claim 6 or 7, wherein said box is provided with means for securing the box to a floor.

9. A sign according to claim 6, 7 or 8, wherein said box is formed with a collar to engage around a corresponding recess provided in a surface of a floor, wall or the like.

10. A sign according to any of the preceding claims, wherein said elements are substantially straight.

11. A sign according to any of the preceding claims, wherein said symbol is an arrow.

12. A sign according to any of the preceding claims, wherein each said element comprises a tube containing a fluorescent material and a radioactive gas which causes said material to fluoresce.

13. A sign according to claim 12, wherein each said tube is of glass and said fluorescent material is a phosphor.

14. A sign according to claim 12 or 13, wherein said gas is tritium.

15. A sign according to any of the preceding claims, being of substantially circular shape in plan view.

16. A lighting system comprising a plurality of signs according to any of the preceding claims, each of which is floor-mounted or mounted at a low- level in a wall or the like so as to be substantially flush with the floor or wall surface.

17. A sign comprising: at least one self-powered light-emitting element arranged to form the shape of at least one symbol; a base in which the or each said element is located; a transparent or translucent cover which covers said base and elements; and a box formed with an aperture: wherein said base and cover are mounted in said box, with the or each said element located in said base, said cover secured firmly to said base, and the or each said symbol visible through said cover and said aperture.

18. A sign according to claim 17, wherein said box is adapted to be flush- fitted in a corresponding recess formed in the surface of a supporting floor, wall or the like.

19. A sign according to claim 17 or 18, further comprising any one or more of the features disclosed in the accompanying specification, claims, abstract and/or drawings, in any combination.

20. A lighting system comprising: a. an elongate profile formed with an elongate recess which is open at one side of the profile; b. a tube engaged within said recess; and c. a series of self-powered light-emitting elements engaged within the tube so as to be at least partly visible along said recess.

21. A lighting system according to claim 20, wherein said tube and recess are so shaped as to inhibit rotation of said tube within said recess.

22. A lighting system according to claim 21, wherein said recess and said tube are respectively of substantially C-shaped and D-shaped cross-section, and said profile is provided with ribs which project into said recess to engage with corresponding grooves formed on said tube.

23. A lighting system according to claim 20, 21 or 22, wherein said elements are of substantially circular cross-section.

24. A lighting system according to any of claims 20 to 23, further comprising a carrier in which said elements engage, and which engages within said tube.

25. A lighting system according to claim 24, wherein said elements snap- engage said carrier.

26. A lighting system according to any of claims 20 to 25, further comprising reflection means for reflecting light emitted by said elements in a direction in which said elements are visible along said recess.

27. A lighting system according to any of claims 20 to 26, wherein at least a visible portion of the tube is provided with an anti-scratch surface.

28. A lighting system according to any of claims 20 to 27, wherein said profile is of metal.

29. A lighting system according to any of claims 20 to 28, wherein said profile and/or tube and/or carrier is extruded.

30. A lighting system according to any of claims 20 to 29, wherein said profile is adapted to accommodate an edge of carpet or floor covering.

31. A lighting system according to any of claims 20 to 30, wherein said profile is adapted to be fitted to an emergency push bar.

32. A lighting system according to any of claims 20 to 31, wherein each said element comprises a tube containing a fluorescent material and a radioactive gas which causes said material to fluoresce.

33. A method of installing an emergency indicating system in a building, comprising the steps of securing a lighting system according to any of claims 20 to 32 to a part of the building or a fixture within the building.