This invention relates to a method and a product for use in improving or upgrading the performance of existing fire doors so that they comply with the latest fire safety regulations, thereby saving the time and expense that would be involved in replacing them with new doors.

Fire protection and safety legislation continues to evolve in the United Kingdom and around the world; and, for example, specifies the requirements for fire alarms, smoke alarms, fire doors and fire exits. As regulations tighten and standards are raised, some equipment and fixtures that may previously have been deemed satisfactory are found to fall short of the newly introduced standards and remedial action is then urgently required. A very important example of this is in relation to fire doors. The setting of updated performance standards, together with changes to the materials and methods that can be used, has created an acute problem and which is especially highlighted with regard to the upgrading of existing fire doors and/or their frames, that do not conform to the new regulations, so that they meet the new standards. The current situation sees many thousands of existing fire doors being discarded annually and replaced with completely new fire doors that comply with the latest regulations.

Every commercial and public building, including offices, hotels, hospitals and schools, requires a means of escape and in which fire doors play an exceptionally important part. Furthermore, building regulations in the UK specify that in dwellings over two storeys high every door of a habitable room leading to a stairwell must be a fire door. There are also regulations relating to fire doors in houses in multiple occupation (HMOs).

Every fire door must meet certain criteria covering, for example, the method of their manufacture, the materials that can be used, their standard of performance and the qualifications of the personnel that are authorised to fit them. Fire doors are given a fire resistance rating; for example, an FD30 fire door (by far the largest category) is an internal fire door which gives 30 minutes of fire protection. This is followed in popularity by FD60 fire doors (giving 60 minutes protection) and then to a lesser extent FD20 fire doors (20 minutes protection) and FD120 fire doors (120 minutes protection). Fire doors are conventionally fitted with intumescent strips which, in the event of a fire, will expand to many times their original size, sealing the gap between the door and the door frame through which fire and toxic gas could pass, thereby aiding containment of the fire. These intumescent strips may be self-adhesive or, alternatively, fitted into grooves made either in the door or in the door frame. They will usually run along the length of the hinge and closing sides and across the top of the door or, if attached to the frame, along the two vertical sections (i.e. the hinge jamb and the closing jamb) and across the top of the door frame. An intumescent strip is not required along the bottom of the door or the door frame because in a fire situation a negative pressure results making the air flow in the opposite direction to that at the top of the door.

At some point, every property in the UK requiring fire doors will be subject to a Fire Risk Assessment (FRA). The results of a FRA dictates if a fire door and its frame complies with the regulations. UK fire door regulations state that the gaps between the fire door and its frame should never be more than 4mm or less than 2mm on the hinge side, closing side and top of the door; while at the bottom of a fire door the gap is to be no more than 8mm. Ideally, there is a gap of 3mm at each side and the top of a fire door so as to ensure adequate room for the intumescent strips to activate in the event of a fire, and for the separate smoke seal strips (if installed) to not get damaged by the opening and closing of the door.

If a fire door is found to have excessive gaps (i.e. over 4mm at the top and sides, or over 8mm at the bottom) between it and the frame or floor, the door is deemed non-compliant and must be replaced. In addition, only a suitably accredited and certificated installer can undertake the fitting of a new fire door. In the UK alone, there are estimated to be 30 million non-compliant fire doors currently installed; and 80% of these doors fail due to them having excessive gaps between the door and frame. The excessive gaps are predominantly found on the closing side of the door. However, a large number also have issues on the head and bottom of the door.

In some cases, an excessive gap may be overcome by re-hanging the door - with the hinges suitably re-positioned so that the gap is reduced so as to be within the aforementioned permissible range. For larger gaps, an approach previously adopted was to add a piece of wood fixed to one or more of the door edges to make the door wider/higher (a practice called “re-lipping”). According to current UK regulations, however, this approach is no longer acceptable.

In the UK, fire door manufacturers are required to test their doors by subjecting them to a fire test procedure as specified in BS 476-22:1987 or BS EN 1634-1 :2014. The Regulatory Reform (Fire Safety) Order 2005 reformed the law relating to fire safety in non-domestic premises. Manufacturers test their doors as they are intended to be fitted. Altering the door in any way other than specified by the manufacturer, will nullify the maker’s certification rendering the door non- compliant with fire safety regulations. Consequently, while it is of course possible to replace existing ironmongery (hinges, locks, closing devices, etc.), it is not permitted to cut and/or reshape the door.

There is therefore a need for a method and a product which enables existing fire doors to be improved or upgraded so that they comply with the latest fire safety regulations, thereby saving the time and expense that would be involved in replacing them with new doors. The present invention seeks to provide such a method and a product. It also has the significant advantage of benefitting the environment by greatly reducing the number of existing fire doors that are condemned, and then have to be removed and sent to landfill sites.

According to the present invention there is provided a method for improving or upgrading a fire door so that the gap between the said door and the associated door frame is no more than a first predetermined upper value and no less than a second predetermined lower value at each of the hinge jamb, the closing jamb, the top of the door frame and the bottom of the door frame, wherein the method comprises:- attaching one or more spacers comprising a non-combustible or fire resistant material to at least one of the hinge jamb, the closing jamb, the top of the door frame, the bottom of the door frame or the floor; and attaching an intumescent strip to the said one or more spacers, such that the intumescent strip extends along substantially the entire length of the said one or more spacers, so that it faces the edge of the door.

Typically, the predetermined upper value is 4mm and the predetermined lower value is 2mm at each of the hinge jamb, the closing jamb and the top of the door frame. Typically, the predetermined upper value is 8mm and the predetermined lower value is 2mm at the bottom of the door frame. Additionally, or alternatively, at least one or more spacers comprising a noncombustible or fire resistant material may be attached at the bottom of the door so that the gap between the said bottom of the door and the floor is no more than a predetermined upper value and no less than a predetermined lower value. Typically, the predetermined upper value is 8mm and the predetermined lower value is 2mm. The presence of an intumescent strip is not usually required at the bottom of a fire door. It will be understood that there is usually no frame at the bottom of a door and so, in this case, the one or more spacers comprising a non-combustible or fire resistant material may be attached to the bottom of the door itself.

According to the present invention there is also provided a method for improving or upgrading a fire door, said door comprising a single door or a pair of doors, so that the gap between the said door and the associated door frame at the top and/or the side edges, between the bottom of the said door and the door frame or the floor, and/or between the said pair of doors at their vertical meeting edge, is no more than a first predetermined upper value and no less than a second predetermined lower value, wherein the method comprises attaching one or more spacers comprising a non-combustible or fire resistant material to at least one of the top of the door, the side edge or edges of the door, or the bottom of the door.

The method may further comprise attaching an intumescent strip to the said one or more spacers.

Typically, the predetermined upper value is 8mm and the predetermined lower value is 2mm at the bottom of the door. Typically, the predetermined upper value is 4mm and the predetermined lower value is 2mm at the top, and the side edge or edges of the door.

It will be appreciated that fire doors may be in the form of single doors (i.e. with a single opening door leaf) or double doors (i.e. with a pair of opening doors). In the case where the fire door comprises a pair of doors, the one or more spacers comprising a non-combustible or fire resistant material may be attached to the vertical meeting edges (also referred to as the meeting styles) of either one or both doors.

According to the present invention there is further provided a product in the form of a kit of parts for use in the aforementioned methods, the product comprising one or more spacers comprising a non-combustible or fire resistant material and one or more intumescent strips. Suitable non-combustible or fire resistant materials for use as the spacers (which may also be referred to as fillets or spacer fillets) will be well known to those skilled in the art. Typically, they are graphite based and have an expansion ratio of no more than about 1 :0.5.

Suitable preformed intumescent strips will also be well known to persons skilled in the art. Typically, they contain an exfoliated graphite based intumescent, start to activate at a temperature of about 180 to 200°C and have an expansion ratio of about 18:1 .

The present invention adopts a unique approach that will avoid throwing away many existing fire doors - by enabling them to be improved or upgraded to meet current performance standards - while meeting FRA requirements. According to one embodiment, it does this by focusing on the door frame and not the door itself. The product is fitted to the door frame only - reducing the gap between frame and door - without altering the door in any way; thus maintaining the manufacturer’s certification of their fire door.

The combination of components used in the method and supplied in the product of this invention will depend on the type of existing fire door to be improved or upgraded (for example, whether it is an FD30 or FD60 door), the dimensions of the door (height, width and thickness) and, of course, the size of the gaps between the door and the door frame at each side and at the top, and between the bottom of the door and the floor. It will thus be appreciated that the invention provides a highly flexible approach that is suitable for use with a wide range of doors, including those of non-standard sizes such as may be found in historic or listed properties. In the latter case, this can be especially advantageous because ordering and supplying new fire doors in non-standard sizes (perhaps with an appearance that is sympathetic to their surroundings in the historic or listed property concerned) can be very expensive and time-consuming. It is usually much less expensive and quicker if the existing fire door can be improved or upgraded to the required standard.

The method and product of this invention involve the use of the following components:- a) At least one spacer formed from a non-combustible or fire-resistant material. The width of the spacer will depend upon the type of fire door; for example, typically being 44mm wide for a FD30 door and 54mm wide for a FD60 door. The spacer is supplied in a range of thicknesses; for example: 2mm, 3mm, 4mm and 5mm; and typically in lengths of 2100mm (the height of a standard door). b) A preformed self-adhesive intumescent material, preferably with a decorative finish because it is to be applied on top of the spacer. The intumescent strips are usually supplied in standard 2100mm or 1050mm lengths, with a self-adhesive backing, and typically have a thickness of 1 ,5mm. The width of the intumescent strip will depend upon the type of fire door; for example, being 44mm wide for a FD30 door and 54mm wide for a FD60 door.

It will be appreciated that an important feature of the invention is that the spacer component may comprise a single spacer or a combination of two or more spacers of the same or different thickness chosen to suit the size(s) of the gap(s) between the fire door and the door frame concerned. The spacers will be supplied in a range of thicknesses so that they are available to use individually or in combinations (so as to form a composite structure) appropriate to suit the varying gaps found around existing fire doors.

If desired, the one or more spacers may be contained within a carrier; for example, made of plastic. The use of a carrier - which covers and conceals (at least partially) the spacers - can improve the visual appearance of the one or more spacers when they are in position on the fire door, its associated frame or fixed to the floor beneath the door.

If desired, other accessories, such as surface mounted acoustic and cold smoke seals may also be attached to the fire doors.

Typically, the method of this invention will comprise the following steps:-

1. Measure the gap between the door edge and frame to determine which components will be required. 2. Cut and fit each of the chosen components to the door frame only; remembering to fit the intumescent strip last of all so it faces the door edge without any obstructions.

3. Fix the spacer(s) initially by using the self-adhesive tape found on the back of each spacer. Once all spacers are in place screw/pin fix through all layers into the door frame, typically at 400mm intervals. The intumescent strip can then be fitted using just the self-adhesive tape found on the back.

The following shows the components (in particular, the combination of spacers) that can be used depending upon the size of the gap between the existing door and the door frame. In each case, the intention is to reduce the gap to no more than 4mm and no less than 2mm so as to render the existing fire door compliant with the latest regulations.

Initial gap size Spacers

5mm No spacer, intumescent strip only

6mm Intumescent strip + 2mm spacer

7mm Intumescent strip + 2mm spacer

8mm Intumescent strip + 3mm spacer

9mm Intumescent strip + 4mm spacer

10mm Intumescent strip + 2mm and 4mm spacers

11 mm Intumescent strip + two 3mm spacers

12mm Intumescent strip + 4mm and 3mm spacers

13mm Intumescent strip + two 4mm spacers

15mm Intumescent strip + two 5mm spacers The present invention is illustrated in the accompanying drawings, in which:- Figure 1 is a perspective view of the closing jamb of a door frame.

Figures 2A and 2B are cross-sectional plan views of an FD30 fire door and an FD60 fire door, respectively.

Figure 3 is a front view of the leading edge of a fire door.

Figure 4 is a front view of a fire door consisting of a set of double doors.

Referring to Figure 1 , a spacer 3 formed from a non-combustible or fire resistant material is attached to the closing jamb 1 of the door frame. An intumescent strip 4 is in position on top of the said spacer. The door frame also includes a door stop 2 against which the door rests when it is in the closed position.

Referring to Figure 2A, the FD30 fire door 5 shown is 44mm thick. There is only an intumescent strip 7 of 1 ,5mm thickness attached to the hinge jamb 8 of the door frame; while attached to the closing jamb 9 of the fire door there is attached a composite structure formed from a combination of a first spacer 10 having a thickness of 5mm, a second spacer 11 with a thickness of 3mm and an intumescent strip 12 that is 1.5mm thick.

Referring to Figure 2B, the FD60 fire door 5 shown is 54mm thick. There is only an intumescent strip 7 of 1 ,5mm thickness attached to the hinge jamb 8 of the door frame; while attached to the closing jamb 9 of the fire door there is attached a composite structure formed from a combination of a first spacer 10 having a thickness of 5mm, a second spacer 11 with a thickness of 3mm and an intumescent strip 12 that is 1.5mm thick.

Referring to Figure 3, multiple spacers 15 are attached to the bottom of the fire door 13. The layers of spacers are within a carrier 14 positioned at the bottom of the fire door. The carrier is optional but improves the visual appearance of the spacers and may be made, for example, from a plastic material.

Referring to Figure 4, the fire door consists of a set of double doors 16 with an associated door frame 17. There is a large gap 18 between the vertical meeting edges of the double doors and which is excessive (and unacceptable) in a fire door. According to the present invention, this type of fire door can be improved or upgraded by attaching one or more spacers and, usually, intumescent strips to the vertical meeting edge (also known as the meeting style) of one or, more usually, both of the doors. The illustrated arrangements are of course only exemplary of the many combinations possible using the present invention as set out in the accompanying claims.

In countries with different fire door regulations to the UK, it is to be understood that the one or more spacers could be attached to the top and/or sides of the door itself (instead of, or in addition to, the door frame). This embodiment is within the scope of the present invention.