Prior art Fire doors are used to prevent fires from spreading within and between buildings. A typical fire door comprises a door leaf which is fixed to a door frame. The door frame comprises a plurality of frame elements, usually two vertical, mutually parallel frame sides and a horizontal frame head and a horizontal frame bottom or sill, which is parallel with the frame head. These frame elements are joined together to a door frame, which is fixedly anchored to one of the walls of the building in a door aperture. In order to prevent a fire which has broken out from spreading through a closed fire door, the door should have two principal characteristics. On the one hand, it should stop fire from breaking through the door. This is achieved by configuring the door leaf and the frame in a non-combustible material, usually steel.

In addition, the door should be configured to stop heat, as far as possible, from being transported through the door. That is to say, even if the side of the door which is facing the seat of the fire becomes very hot, the opposite side should remain at as low a temperature as possible to prevent, or at least delay, a new fire seat from forming on the other side of the door. The present invention also relates to a new configuration of the frame elements, which improves the capacity of the frame to inhibit heat transport.

According to the prior art, frame elements for fire doors are usually configured as elongated profile elements made of bent steel plate or extruded aluminum. Each frame element is substantially constituted by an elongated profile element of this kind and means for fixing the frame element to the wall, a sealing strip for effecting a seal between the frame element and the door leaf and internal insulation for inhibiting heat transport by radiation and convection through the profile element.

The profile element has a number of wall sections extending along the full length of the element. These wall sections form a cross section of the profile element having a generally rectangular part, which latter has an open side intended to face the short side of the wall in the door aperture. On this side there might also be means present for fixing door or frame architraves, which, one on each side of the wall, extend from the profile element in over the wall a bit. In DE 20109826, it is described how door architraves according to the prior art can be fixed to a frame element. On that side of the profile element of the frame element which is facing away from the open side facing the wall, a number of wall sections further form a projection having a stop against which the door leaf is intended to bear when the door leaf is in the closed position. Usually the door leaf does not bear directly against the stop, but a sealing strip is disposed between the stop and the door leaf.

In another previously known frame element, that space in the profile element which corresponds to the generally rectangular part of the cross section of the profile element is filled with heat-insulating mineral wool. The purpose of the mineral wool insulation is to inhibit heat from being transported by radiation or convection from one of the wall sections forming the rectangular part to

another. Three wall sections of the profile element further form a groove between the rectangular part of the profile element and the stop. The groove extends along the full length of the profile element. In the groove there is disposed a strip of a heat-insulating material which expands upon heating. In normal use of the door, this strip aims to effect a seal between the frame element and the door leaf. In case of a fire, that side of the door which faces the fire seat will be fiercely heated. Since those parts of door leaf and frame which are closest to the seat are heated and expanded more than the parts on that side of the door facing away from the seat, deformations then occur in door leaf and frame. The expanding insulating strip aims in this case to maintain a good seal between door leaf and frame in spite of the occurring deformations. Since the strip increasingly expands as the temperature rises, the insulating material will force its way into the gaps between door leaf and frame which are formed by the deformations. A good seal is thereupon maintained between door leaf and frame element, at the same time as heat transport between door leaf and frame element is inhibited.

A disadvantage of the known construction described above is that it is difficult to achieve a good internal mineral wool insulation between the wall sections of the profile element which form the groove and the stop. The internal spaces and the distances between these wall sections are relatively small. It is therefore complicated and costly, in the production of the frame elements, to apply mineral wool or other heat insulation in these spaces. Even if mineral wool or other conventional heat insulation were to be applied in these spaces, good heat insulation between the wall sections would still not be obtained. Since these wall sections are deformed when heated and since conventional

insulation does not follow such deformations, gaps are formed between wall sections and insulation, whereupon the insulating effect, as regards radiation and convection, is considerably impaired. The deformations can also cause the insulating material between two or more wall sections to be pushed totally aside, with the result that the radiation and convection insulation between these wall sections wholly disappears.

The small distances between the wall sections in this part of the profile element further mean that heat transport by radiation and convection between the wall sections is especially significant here. Moreover, these wall sections are located in precisely that part of the profile element which, in terms of heat transport, constitutes the boundary between the hot and cool side of the frame element when one or other side of the frame element is heated. A good counteraction to heat transport is therefore especially important in precisely this part of the profile element in order to prevent heat, as far as possible, from spreading from one to the other side of the fire door.

Apart from by radiation and convection, heat can also be transported between the different wall sections of the profile element by heat conduction. BE 827106 describes a metal profile element for a frame element, which profile element also has a groove for a sealing strip and a stop for the door leaf. In order to inhibit heat transport through the profile element, a number of circular openings are made in the wall section forming the groove.

The openings are arranged one behind the other in the longitudinal direction of the profile element. Hence the wall section limiting the groove is, in fact, perforated, so that the wall section will contain less heat- insulating material than if the wall section were solid.

Heat transport through the profile element is thus inhibited by reducing the heat-conducting properties of the profile element through the removal of heat- conducting material. A drawback of the profile element described in BE 827106 is, however, that heat can continue to be transported through the openings themselves. Since the openings, in practice, are filled with air, heat transport is permitted within each opening by radiation and convection between different parts of the marginal surface of the respective opening. Since the perforated wall section, moreover, is located in that part of the profile element which, in terms of heat transport, constitutes the boundary between the hot and cool side of the frame element, such heat transport by radiation and convection adversely and significantly affects the capacity of the frame element to inhibit heat transport.

The object of the present invention is therefore a frame element in which heat transport through critical parts of the frame element, both by heat conduction and by radiation and convection, is simply and effectively inhibited.

This object is achieved according to the invention with a frame element according to the first paragraph, which is characterized in that at least one opening is arranged through a first wall section of the profile element, close to the expanding insulating material, to allow the insulating material to expand through the opening if the frame element is heated, so that heat transport through the frame element is inhibited.

By arranging one or more openings in the first wall section, heat conduction through the material in the first wall section is effectively inhibited. This is the

case both before and after the expanding insulating material has begun to expand as a result of heating arising from a broken-out fire, or the like. Since the openings, moreover, are arranged close to the expanding insulating material, this insulating material, when it expands upon heating, will force its way into and fill the openings. Once the insulating material has filled the openings, heat transport by radiation and convection through the openings, that is to say between different parts of the marginal surface of each opening, is effectively inhibited. The invention thus offers a simple and effective device for inhibiting heat transport through the frame element with respect to both heat conduction and radiation and convection.

According to an advantageous embodiment of the frame element, the profile element comprises a second wall section, which is arranged so that a space is formed between the first and second wall section. The openings and the insulating material are in this case arranged so that the insulating material, when it expands, wholly or partially fills the space between the first and second wall section. This has the effect of inhibiting heat transport by radiation and convection between different wall sections of the profile element. By choosing a suitable positioning of the openings and the insulating material relative to the wall sections, it is possible greatly to inhibit radiation and convection in heat- transport-critical parts of the profile element. Examples of such critical parts are between two parallel adjacent wall sections and at right-angled or acute angle joints between two wall sections.

The frame element can further expediently be configured so that the insulating material is arranged on that side of the first wall section situated opposite the second

wall section. This has the advantage that the insulating material, when heated, both forces its way through and fills the openings and also fills the space between the first and second wall section, whereby radiation and convection are inhibited both within the openings and between the wall sections.

According to a preferred embodiment of the frame element according to the invention, the profile element is configured such that two or more wall sections form a laterally open groove extending in the longitudinal direction of the profile element. The depth of the groove is defined by a wall section constituting a stop for the door leaf when this is in the closed position. The insulating material is arranged in the groove so that it protrudes past the stop. The insulating material will consequently act as a seal between frame element and door leaf when the door is closed. One or more of the wall sections which form the groove is/are provided with one or more sets of openings. Within each set, the openings are arranged in line along the length of the profile element. This has the effect that the insulating material, when it expands, fully and along the length of the entire profile element, is able to fill the spaces on both sides of the wall section having the set of openings. This without prejudice to the strength of the profile element. Sets of openings are expediently placed on those wall sections which have adjacent second wall sections, for example the wall sections forming the groove, where the risk of heat transport by radiation and convection is high.

Description of preferred embodiments of the invention Various embodiments of the invention are described below with reference to the figures, in which:

Fig. 1 shows a perspective view of a part of a profile element intended for use in a frame element according to the invention.

Fig. 2 shows a section through a frame element according to the invention prior to heating and expansion of the insulating material.

Fig. 3 shows the section in fig. 2 after the insulating material has begun to expand.

Fig. 4 shows a section through a frame element according to an alternative embodiment after the insulating material has been heated and expanded.

Fig. 5 shows a section through a frame element according to a further embodiment, after the insulating material has been heated and expanded.

Figure 1 shows in perspective a part of a profile element 1 which is intended to form part of a frame element according to the invention. The profile element is constituted by an elongated body formed by bent or rolled steel plate. Alternatively, the profile element can be made by extrusion of aluminum. The wall of the profile element consists of a number of elongated wall sections 5-15, which are parallel with the longitudinal axis of the profile element.

In figures 2-5 are shown various embodiments of the frame element fixed in a door aperture of a structural wall 4 by means of fastening devices (not shown). The frame element comprises the profile element 1 shown in figure 1. The section in figures 2-5 is taken perpendicular to the longitudinal axis of the frame element and profile element and, viewed from below, is the profile element

shown in figure 1. Also indicated in the figures, by dashed line, is a door leaf 20 in the closed position.

Referring firstly to fig. 2, the cross section of the profile element 1 has a generally rectangular part 2 and a projection 3 protruding from the rectangular part. The generally rectangular part 2 is formed by the wall sections 6,7, 8,13, 14. On one side of the rectangular part 2, the wall of the profile element is open. This side is facing the short side of the wall 4, which short side faces the door aperture. Extending through the open part 16 of the profile element wall, at a number of points along the length of the frame element, are adjusting and fastening screws (not shown), which, with their one end, bear against or penetrate into the short side of the wall 4. These screws are fixedly connected at their other end to the wall section 8, situated opposite the wall, of the generally rectangular part 8. The rectangular part 8 is further filled with mineral wool 17 in order to stop heat from being transported by radiation and convection between the different wall sections of this part 2.

In figure 2 it is also shown how two frame or door architraves 31,32 are fixed to the frame element. The two architraves 31,32 are configured as elongated profile elements made of bent or rolled steel plate.

Alternatively, they can be constructed in extruded aluminum.

The cross section of the upper architrave 31 shown in figure 2 is formed by three wall sections 33,34, 35 and has a general J-shape incorporating a longer side member 33, a bottom 34 and a shorter side member 35. The architrave 31 is detachably fixed to the frame element by means of a number of, preferably three, snap fasteners

distributed along the length of the architrave 31 and frame element. The frame element has, for this purpose, a first architrave groove 38, formed by the wall sections 5 and 6. In one of these wall sections, the wall section 6 in the illustrated example, three openings 36 are arranged, one close to each end of the frame element and one in the middle. The longer side member 33 of the architrave 31 has three corresponding punched bulges 37.

These openings 36 and bulges 37 constitute the snap fasteners for fastening of the architrave. In the fitting of the architrave 31, the longer side member 33 is inserted into the groove 38, the elasticity in the material belonging to the wall sections of the architrave and frame element allowing the bulges 37 to snap into the openings 36. The positioning of the openings 36 in the groove 38 and of the bulges 37 on the side member 33 are configured such that the short side 39 of the shorter side member 35 of the architrave 31 ends up level with the surface of the structural wall 4.

The lower architrave 32 shown in figure 2 is fixed differently to the frame element. The cross section of this architrave 32 also has a general J-shape, but in this architrave 32 the longer side member 40 is substantially longer relative to the shorter side member 42 than in the architrave 31. The frame element has a second architrave groove 43, which is formed by the wall sections 14 and 15 of the profile element 1. This architrave groove 43 is usually substantially deeper than the first architrave groove 38 for the architrave 31. In the fitting of the architrave 32, it is firstly inserted into the groove to such a depth that the short side 44 of the shorter side member 42 of the architrave 32 bears against the wall 4. Next the longer side member 40 of the architrave is fixed in the groove 43 by a number of self- boring screws 45 being screwed through the two wall

sections 14,15 of the profile element 1 which form the groove 43 and through the longer side member 40 of the architrave 32. For this purpose, a number of openings (not shown) are arranged in the wall section 12 of the profile element, through which openings screw and screwdriver can be introduced for tightening of the screws. Normally three screws 45 are used, one close to each end of the profile element and one in the middle.

There are a number of advantages with this new method of applying door or frame architraves to the frame elements.

Firstly, the system allows simple fastening and removal of the architraves 31,32, which in turn means that the architraves can be easily replaced if so desired.

Secondly, it enables many different models of architrave, as regards shape and color, to be offered for one and the same type of door frame. The greatest advantage with the architrave/frame combination described above lies, however, in the fact that one and the same architrave can be used for structural walls of different thicknesses.

The system offers continuous adjustment to different wall thicknesses. Since the groove 43 is relatively deep, normally 30-50 mm, preferably around 40 mm, and the longer side member 40 of the architrave 32 is relatively long, usually 35-400 mm, preferably around 75 mm, one and the same architrave/frame combination can be used for walls whose thickness differs by up to 35 mm. It is possible, moreover, for one and the same type of door frame to offer architraves 32 in which the length of the longer side member 40 varies. A modular system is thereby obtained which is suitable for all wall thicknesses. A further advantage with the flexible fastening of the lower architrave 32 shown in figure 2 is that it is possible in the fitting to compensate for variations in wall thickness along the length of the frame element.

On that side of the generally rectangular part 2 of the profile element 1 which is situated opposite the wall 4 the projection 3 is arranged. The projection 3 is formed by a number of wall sections 9-13, forming an open groove 18, a stop 11 and a supporting wall 12 for the stop. The groove 18 normally extends essentially along the entire length of the profile element. If so required, it can, however, be shorter than the profile element, for example to allow a plurality of frame elements to be joined together into a frame. In the illustrated example, the groove is formed by three wall sections 8,9, 10, the cross section of the groove having a general U-shape. The cross section of the groove can also, however, assume a number of different shapes, in which the groove is formed by just two or more than three longitudinal wall sections. The groove 18 is further limited in the outward direction, at its open part, by a wall section 11 constituting the stop for the door leaf 20, which door leaf is shown in dashed representation in figures 2-5 when in the closed position.

In the groove 18 there is disposed a strip 21 of expanding heat-insulating material, essentially along the entire length of the groove 18. The nature of the insulating material is such that it expands strongly if heated. The material further insulates against heat transport by radiation and convection, both before and after it has expanded. Moreover, it has good gas-sealing and smoke-sealing properties.

Examples of materials which can be used to form the strip are various blends of graphite, synthetic bonding agents and sealing means. Depending on the composition, such insulating materials begin to expand at around 170-190°C.

Under continued heating, the material expansion then continues to around 700-800°C. Typically, such a material

has increased its volume by about 18 times if heated to 550°C under load and by 37 times if heated to 450°C without load. Alternatively, a so-called fire strip, which is sold by BASF under the trade name"Palosol", can be used. This material increases its volume by around 15 times when heated from 120°C to 600°C.

The strip 21 of the expanding insulating material is arranged in the groove 18 in such a way that it fills the groove and protrudes beyond the stop 11, so that it will seal against the door leaf 20 when this is in the closed position. As is shown in figures 2-4, in order further to improve the sealing effect against the door leaf 20, a conventional rubber sealing strip 22 can be vulcanized together with the expanding material at that part of the expanding material which protrudes past the stop 11.

According to a first embodiment (see fig. 2 and 3) of the invention, a set of openings 23 is arranged in the wall section 10 which limits the groove 18 on that side of the groove facing inward toward the door aperture, that is to say the wall section 10 which, in the cross section of the profile element, extends from the bottom 9 of the groove to the wall section 11 constituting the stop. The set of openings 23 extends essentially along the full length of the profile element and consists of a plurality of slots arranged one behind the other in the longitudinal direction of the profile element. The slots are elongated in the longitudinal direction of the profile element and are typically 10-40 mm, preferably 30 mm long, and 3-5 mm, preferably 4.4 mm wide, the interval between the slots in a set typically measuring 3-5 mm, preferably 4.4 mm.

When a fire has broken out on, for example, the side of the door facing downward in figure 2 and 3, that side of

the door which faces the fire seat will be fiercely heated. Typically, the temperature of this side of the frame elements of the door after 60 minutes'fire can reach around 850°C. The mineral wool insulation 17 in the rectangular part 2 of the frame element inhibits heat from being transported by radiation and convection from those wall sections 13,14 of the rectangular part which are facing and directly exposed to the fire to the non- directly exposed, "cool"wall sections 6,7, 8 of the rectangular part. The slots 23 further achieve that heat transport by conduction from those wall sections 11-14 of the whole profile element which are directly exposed to the fire to the non-directly exposed wall sections 5-9 of the profile element is inhibited. Nevertheless, heat will be transported to the wall sections 8,9, 10 forming the groove. The temperature of the expanding insulating strip will also in the process be raised.

Once the temperature of the strip reaches around 170- 190°C (if a graphite strip is used), the insulating material begins to expand (see fig. 3). Since the slots 23 according to the invention are arranged close to the insulating material, this material will now force its way into and totally fill the slots 23. This also inhibits heat from being transported by radiation and convection between the marginal surfaces of each slot 23. The total heat transport through the wall section 10 in which the slots are arranged is thus substantially reduced. This reduction in heat transport is particularly important in this wall section, since the wall section constitutes a boundary, in terms of heat transport, between that part of the frame element which is directly exposed to the heat from the fire seat and the non-exposed part.

When the insulating material 21 expands, it will additionally force its way through the slots 23 and

totally fill the space between the wall section 10 in which the slots are arranged and the wall section 12 which constitutes a supporting wall for the stop 11.

Radiation and convection between these wall sections 10, 12, and between these two wall sections 10,12 and the wall section 11 constituting the stop, is thereby inhibited. Since the distances between all these three wall sections 10,11, 12 are relatively small, so that radiation and convection between them would otherwise be significant, such an inhibiting effect is important.

These three wall sections 10,11, 12 are also located on the boundary between the exposed and non-exposed parts of the frame element, thereby further increasing the importance of the achieved reduction in heat transport.

A further important effect lies in the fact that the insulating material 21, as it gradually expands, follows the surrounding geometries. The insulating material thus fills all the spaces between the surrounding wall sections 10,11, 12, even if these are deformed by uneven heating. Empty spaces are thereby prevented from being formed between the wall sections, in which empty spaces the radiation-inhibiting and convection-inhibiting effect would otherwise be lost.

Another positive effect of the invention is that the insulating material 21 consumes heat as it expands.

During the expansion of the insulating material, heat is therefore transferred from surrounding wall sections to the insulating material. This means a reduced increase in temperature in these surrounding wall sections, which in turn inhibits heat transport through the profile element.

It should be noted that the insulating material 21 also expands in the direction viewed outward from the groove 18. As it does so, the insulating material 21 will fill

any spaces and gaps between the door leaf 20 and the frame element, which spaces and gaps can be present from the start or can be formed by thermal deformations which have occurred. In this way, the expanded insulating material 21 also inhibits heat transport both by conduction and by radiation and convection between the door leaf 20 and the frame element. Moreover, a good seal is ensured, which prevents gases and smoke from forcing their way out through the door.

According to a second embodiment (see fig. 4), a set 24 of slots is arranged in the wall element 9 which constitutes the bottom of the groove. Corresponding effects are herein obtained in terms of inhibiting heat transport by conduction, and radiation and convection, through the frame element. The difference in this embodiment compared with the one described above is that heat conduction is inhibited in the wall section constituting the bottom 9 of the groove. If the dimensional relationship between the volume of insulating material 21 which is accommodated in the groove 18 and the inner volume of the projection 3 is optimized with regard to the expandability of the insulating material, the insulating material, when it expands, can be made to fill the whole of the inner space of the projection 3.

Heat transport by radiation and convection between all the critically placed wall sections 9,10, 11,12, 13 forming the projection 3 is in this case successfully inhibited in a simple manner.

According to a third embodiment (see fig. 1), slots 25 are arranged in the wall section 8 which limits the groove against the generally rectangular part of the profile element. This primarily has the effect of inhibiting heat conduction, and radiation and convection,

through the wall section itself 8, as well as through its openings.

According to a fourth embodiment (see fig. 5), openings 26 are arranged in the wall section 11 constituting the stop and the expanding insulating material is arranged on the opposite side of this wall element 11 relative to the door leaf 20. As the insulating material expands, it then forces its way, on the one hand, through the openings and fills any gaps formed between the door leaf and the frame element, whereby both conduction and radiation and convection between said door leaf and frame element are inhibited. At the same time, the insulating material expands also out into the inner space of the projection 3, so that the advantages described in connection with the second embodiment above are also obtained.

Trial A fire test according to Swedish and European testing standard SSEN 1634-1 was conducted on a fire door provided with frame elements according to the invention and on a reference door. In this, a fire door provided with a frame made up of three frame elements (two door frame sides and one door frame head) according to the invention, and a sill, was gradually heated on one side.

The frame elements were configured in accordance with the third embodiment above. That is to say, the strip 21 of expanding insulating material was arranged in a U-shaped groove 18 between the rectangular part 2 of the profile element and the stop 11 and a set of openings in the form of elongated slots was arranged in the wall section 8 which constituted the wall of the groove against the rectangular part 2 of the profile element. The slots were 30 mm long, 4.4 mm wide and placed at 4.4 mm intervals along the entire length of the respective frame element, 8 mm into the wall section 8 from the bottom 9 of the

groove. As reference, the same tests were conducted with an identical fire door without such openings. During the heating process, the rise in temperature was measured at a number of measuring points, which were identically positioned on the second, non-directly heated side of the frames. The result for one of these measuring points (Atemp. = the current temperature of the measuring point - the original temperature at the measuring point) is set out below: Time Atemp. Atemp. with Difference Difference [min. ] without openings [°C] [°C] [%] openings [°C] 30 237 229 8 3. 4 36 266 257 9 3. 4 60 344 325 19 5. 5 68 357 338 19 I5. 3 As can be seen from the table above, heat transport through the frame was inhibited to a substantially higher degree in the fire door provided with frame elements according to the invention.

According to the invention, it is possible, of course, to combine more than one of the embodiments described above and also to place the openings, with adjacent expanding insulating material, in other wall sections in which it is desirable to inhibit heat transport by both conduction and radiation and convection.

The invention has been described above in connection with a fire door. It is also possible, of course, to use the frame element in other applications, such as with windows, hatches or front doors, in which it is desirable to inhibit heat transport through the frame.