GB2405437A

GB2405437A - Fire resistant flexible sheet used in roof construction and a kit including a fire resistant sheet

Info

Publication number: GB2405437A
Application number: GB0319972A
Authority: GB
Inventors: Michael Anthony Turner; Vivienne Fisher; Philip Ingham
Original assignee: TBA TEXTILES Ltd
Current assignee: TBA TEXTILES Ltd
Priority date: 2003-08-27
Filing date: 2003-08-27
Publication date: 2005-03-02
Anticipated expiration: 2023-08-27
Also published as: GB2405437B; GB0319972D0

Abstract

A loft space is converted into a living space by laying a sheet of fire retardant material between adjacent joists 14. A metal plate 30 traps the sheet 28 against the side walls of the joists. Nails extend through the plate 30 to hold the plate in position. Additional joists 22 are added to increase the floor strength of the loft.

Description

1 2405437

LOFT CONVERSIONS

The present invention relates to a method of converting a loft space into a living space including enhancing the fire protection of the loft space, a loft space conversion in which a loft space has been converted into a living space, the conversion including enhancing the fire resistance and a kit of parts for converting a loft space into a living space.

When converting a loft into a living space when the house is already two stories high then, in order to comply with building regulations, fire protection must be provided between the ceiling of the floor below and the floor of IS the loft. The fire protection provided must protect against fire, smoke and heat transfer for at least 30 minutes.

Figure 1 shows a side view of a ceiling 10 of a room below a loft space 12, with joists 14, typically, at 400 to 600 mm spacing used in the original house, before conversion of the loft was considered. Fire protection in this conversion is provided in the form of a wad of non woven mineral fibres 16. The fibres are held in cages 18 of chicken wire between the joists 14.

The use of mineral fibres has two disadvantages. The first is that it is difficult if not impossible in practice to ensure that the air gaps between the fibres and the joist is elminated. In addition it may be difficult to get the fibres to the bottom corners thereby leaving a gap 18. Thus there is a small space 20 at those corners. The depth of the wad of fibres is required to be at least 50 mm and thus the cages are of that depth. The effective depth at the corners can be significantly less than 50 mm and thus the mineral product may not necessarily provide the statutory fire protection across the complete extent of the floor. Accordingly fire may spread between the fibres and the joist or the joist may char inwardly not only from the bottom surface but also from the side surface.

In addition, the joists 14 are often of insufficient strength to support the additional floor loading required when a conversion is effected. Consequently additional joists 22 are provided of greater strength. These joists are positioned above the fibres 16. As the wad of fibres is 50 mm in depth this results in a reduction in the vertical height available in the loft space thereby giving the second disadvantage.

It is an object of the present invention to attempt to overcome at least some of the above or other disadvantages.

The present invention is defined in the attached claims.

The present invention can be carried into practice in various ways but some embodiments will now be described with reference to the accompanying drawings, in which: Figure 2 is a side view of a first embodiment of a floor space conversion for a lofts and Figures 3 and 4 are similar views of further embodiments; Figure 5 is a side view of a fire retarding sheet showing a joint that may be used between such adjacent layers.

As shown in Figure 2, an existing ceiling 12 with existing joists 14 is to be fire protected for smoke and heat or any combination thereof to a specified standard.

To effect this protection, a protective membrane or skin or sheet 28 is provided between the joists 14.

The protective sheet may be as described in our co-pending UK patent applications Nos: UK 2311006, 2311007 or 2311008

the disclosures of which are hereby incorporated.

Alternatively or additionally, the sheet may be that sold by the applicant under FIREFLY PLUS 30 or FIREFLY PLUS 60 (FIREFLY is a Registered Trade Mark of the applicant).

The sheet may have any combination of the following characteristics:

DESCRIPTION Composite Cavity Fire

Barrier.

Combined integrity and insulation.

Suitable for vertical and horizontal applications.

WEIGHT 2.2Kg/m nominal THICKNESS 10 mm nominal BS 476 PART FIRE PROPAGATION TEST Fire Propagation Index WIRA Testing Centre 2.56 BS 476 PART 7 Certification to "Class 1" SURFACE SPREAD OF FLAME pass WIRA Testing Centre BS 476 CLASS "0" BUILDING Complies with requirements

REGULATIONS

WIRA Testing Centre BS 476 PART 20/22 1987 CLAUSE 5 INTEGRITY: 30 minutes Faverdale Technology Centre & INSULATION: 30 minutes Tested and Assessed at Loss

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Prevention Council BS476.PART 20/22 1987 - HORIZONTAL INTEGRITY: 30 minutes Tested and Assessed at Loss INSULATION: 30 minutes Prevention Council BS476 PART 20 1987/PREN 1366-3: INTEGRITY: 30 minutes 1993 PENETRATION SYSTEM Warrington Fire Research

_

SOUND REDUCTION INDEX IN ACCORDANCE 16 dB

WITH THE PRINCIPALS OF BS EN ISO

140/111 1995 The University of Salford The flexible sheet 28 is fitted as follows.

A roll of the sheet 28 is unwound to cover at least one joist. A continuous steel strip 30 of 30 mm by 0.5 mm and 6 m in length is then urged downwardly and against each side wall of the joist that the sheet covers to trap the sheet against the joist and as near to the ceiling as possible. This will prevent or minimise any chasing of the joist that may occur from the side walls of the joist.

The steel strip 30 has a number of openings along its length at 250 mm spacing. Fire rated fixings 32 which may be nails or screws are inserted through those openings into the joist to fix the sheet firmly in place against the joist. The fixings are inserted to a sufficient depth to remain in situ for the required duration of fire protection (i.e. 30 mine) . The fixings may extend more than half the way across the joists. The openings in the strips 30 may be staggered.

Either before or after locating the strips 30 in position or before or after inserting the fixings, the sheet may be cut along a line 34 simply by running a knife down the length of the joist. The free wall of the layer created by this cut may then be laid over into the space defined between adjacent joists. It can be seen that one roll can fireproof the space between 3 successive joists.

As the sheet is trapped against lower end and sides of the joists sufficient fireproofing is provided. This is because the sheet provides adequate protection, as does the wood of the joists.

A new floor can then be mounted on the joists 14 if they are strong enough to support the conversion.

Alternatively, joists 22 of increased strength can be located above the sheet but between the joists 14 with the new floor being mounted on the added joists 22. As one sheet 28 is 10 mm thick, the new joists have their base 10 mm higher than the old joists. Thus the depth of the new joists does not sufficiently reduce the effective height of the converted space. It will be appreciated that the sheet may be 5 mm thick or less, as described later, or any thickness, provided sufficient fire protection is provided.

Figure 3 shows a loft space similar to that of Figure 2.

The traditional joists 14 are shown with additional joists 22 having been added for strength purposes. The way that the sheet is added though applies whether or not additional joists have been added. In this instance, the sheet 28 (which is as previously described) is laid over the joists 22 and attached to the joists. The sheet may extend across joists in the upper region of the joists or may stay down or rest on the ceiling between joists.

Attachment may be by nails only directly attaching the sheet to the joist or by strips 30 and fixing attaching the sheet to the top of the joists or any other appropriate attachment method. In an alternative embodiment the sheet is laid over the joists 14 with the joists 22, if present, being above the sheet.

Figure 5 shows an arrangement in which the sheet 28 extends down the sides of the new joists 22 and under their base. The sheet may be attached to the joists 22 from one or both sides. The fasteners 32 used to effect the attachment may attach the sheet directly to the joists or indirectly by the use of a strip which may comprise the strip 30 as previously described.

It will be appreciated that it may be necessary to effect a joint 35 between adjacent separate sheets. Such a joint is shown in Figure 5 as in the prior publications referred to previously. Other such fire tested joints may be used.

The first illustrative flexible fire barrier 36 in Figure comprises two outer layers 38 and 40 of metallic foil, and two insulating assemblies 42 and 44 positioned between the two outer layers having a total thickness of 5 mm.

The outer layers 38 and 40 are identical to one another and both comprise a layer of woven fabric made of E-glass fibre which has been coated with a chemical to make it heat resistant. Such a fabric is available commercially from TBA Textiles Limited of Rochdale, England under the tradename "Firefly PHOENIX". The layers 38 and 40 are formed from fibres having a diameter greater than 3 micrometres and have a thickness of 0.4 mm.

The insulating assemblies 42 and 44 are identical to one another and each comprises a glass fibre insulating layer in the form of a mat, 42 and 44 respectively. Each mat 42 and 44 is a needled felt made from E-glass fibre having a diameter greater than 3 micrometres. Each mat 42 and 44 is approximately 5 mm in thickness and has a density of Kg/m3. Each assembly 44 and 46 also comprises two metallic layers formed by sheets of aluminium foil, 42b and 42c, and 44b and 44c respectively. The sheets 42b and 42c or (44b and 44c) form an envelope enclosing the mat 42a or 44a. Each sheet of aluminium foil is approximately micrometres in thickness and extends across one face of a mat 42a (or 44a). The edges of the sheets 42b and 44c (or 44b and 44c) are joined together around the edges of the mat 42a (or 44a) to complete the envelope.

The layers 38, 40, 42 and 44 forming the barrier 46 are secured together in overlying relationship by adhesive.

At the joint, edge portions of the assemblies 42 and 44 of said adjacent lengths overlap one another. Specifically, the assemblies 42 and 44 of the two lengths are interleaved. Furthermore, at the joint, the outer layers 38 and 40 of the adjacent lengths are joined together to hold the assemblies 42 and 44 in their overlapping condition.

To make a joint shown in Figure 4, an installer first bends edge portions of the outer layers 38 of the two lengths towards themselves. They then join these edge portions together, eg by staples, and fold them over to lie parallel to the layers 38. This creates the seam 48 shown in Figure 4. In order that the installer can work from one side only of the barrier, the seam 48 is made facing the installer and towards the centre of the barrier. Next, the installer interleaves the assemblies 42 and 44 of the two adjacent lengths of barrier. As shown in Figure 4, this interleaving results in the foil sheet 42 of one of the lengths contacting the foil sheet 42 of the adjacent length. Similar contacts are also made between a sheet 42b and a sheet 44b and between sheets 44b and 44c. If desired, one or more of these contacts between the foil sheets can be secured by adhesive.

Finally, the installer makes a folded seam 50 between the outer layers 40 in the same way as he made the seam 48.

The seam 50 faces the installer and away from the centre of the barrier.

In the joint of the fire barrier, none of the foil sheets pass through the barrier. Furthermore, the joint has 4 mats 42a and 44a and sheets of aluminium foil. The joint inhibits the passage of hot gases.

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 method of converting a loft space into a living space including enhancing the fire protection of the loft space between the top of the space below and the loft space, by causing a fire-retardant flexible sheet to extend between spaced joists.

2. A method as claimed in claim 1 comprising attaching the sheet to spaced joists.

3. A method as claimed in claim 2 comprising attaching the sheet with fasteners.

4. A method as claimed in claim 2 or 3 comprising indirectly attaching the sheet.

5. A method as claimed in claim 4 comprising clamping the sheet to a joist.

6. A method as claimed in claim 5 comprising clamping the sheet with a plate.

7. A method as claimed in any of claims 2 to 5 comprising attaching the sheet to the side surface of a joist.

8. A method as claimed in any preceding claim comprising urging the sheet downwardly, towards the base of spaced joists.

9. A method as claimed in claims 6 and 8 or Claims 6, 7 and 8 comprising pushing the plate down prior to clamping the sheet in position.

10. A method as claimed in any of claims 2 to 5 comprising attaching the sheet to the top surface of a joist.

11. A method as claimed in claim 3 or any claim when dependent on claim 3 comprising attaching the sheet with nails.

12. A method as claimed in claim 3 or any claim when dependent on claim 3 comprising causing the fasteners to penetrate more than half the width of a joist.

13. A method as claimed in any preceding claim comprising causing the sheet to rest on top of the top of a ceiling IS of the space below the loft space.

14. A method as claimed in any preceding claim comprising causing the sheet to extend between and contact adjacent spaced joists.

15. A method as claimed in claim 14 comprising attaching the sheet to adjacent spaced joists.

16. A method as claimed in any preceding claim comprising laying the sheet over spaced joists.

17. A method as claimed in claim 16 comprising cutting the sheet in the region of a joist after laying the sheet over spaced joists.

18. A method as claimed in claim 17 comprising causing the cut edges of the sheet to be clear of the top surface of the joist over which the sheet had previously been laid.

19. A method as claimed in any preceding claim comprising adding joists of increased thickness.

20. A method as claimed in claim 19 comprising adding the joists after causing the fire retardant sheet to extend between spaced joists.

21. A method as claimed in claim 19 or 20 comprising causing the base of the added joists to be below the top of the existing joists.

22. A method as claimed in claim 21 comprising causing the base of the added joists to be less than 30 mm above the base of the existing joists.

23. A method as claimed in claim 22 comprising causing the base of the added joists to be less than 20 mm above the base of the existing joists.

24. A method as claimed in claim 23 comprising causing the base of the added joists to be less than 15 or in the region of 10 or 5 mm above the base of the existing joists.

25. A method as claimed in any of claims 19 to 24 comprising causing the sheet to contact the added joists.

26. A method as claimed in claim 25 comprising causing the sheet to contact the base of the added joists.

27. A method as claimed in claim 25 or 26 comprising causing the sheet to contact at least one side of the added joists.

28. A method as claimed in any of claims 25 to 27 comprising connecting the sheet to the added joists.

29 A method as claimed in any preceding claim comprising using a sheet that is less than 30 or less than 20 or less than IS or in the region of 10 or 5 mm thick.

30. A method as claimed in any preceding claim comprising using a laminate sheet having more than one layer.

31. A method as claimed in claim 30 comprising using a sheet that has at least one impervious layer.

32. A method as claimed in claim 31 comprising using an impervious layer comprising a metallic foil layer.

33. A method as claimed in claim 30, 31 or 32 comprising using a sheet that has at least one insulating layer.

34. A method as claimed in any preceding claim comprising joining two edge regions of adjacent sheets together.

35. A method as claimed in claim 34 comprising joining edge regions of adjacent sheets together by overlapping at least two layers of one sheet with two layers of the other sheet.

36. A method of converting a loft space into a living space substantially as herein described with reference to and as shown in any of the accompanying drawings.

37. A loft space conversion in which a loft space has been converted into a living space, the conversion including a sheet of fire resistant material between spaced joists.

38. A loft space conversion substantially as herein described with reference to and as shown in the accompanying drawings.

39. A loft space conversion as claimed in claim 37 or 38 using a method as claimed in any of claims 1 to 36.

40. A kit of parts for converting a loft space into a living space including a fire resistant sheet in which, in use, the sheet is caused to extend between two spaced joists.

41. A kit as claimed in claim 40 including joists of greater strength than existing joists in which, in use, the joists are included in the loft space.

42. A kit as claimed in claim 40 or 41 including fasteners which, in use, are arranged to locate the sheet to joists.

43. A kit as claimed in any of claims 40 to 42 including a clamp arranged, in use, to clamp the sheet against a joist.

44. A kit of parts substantially as herein described with reference to and as shown in any of the accompanying drawings.

45. A kit of parts as claimed in any of claims 40 to 44 when used in a method as claimed in any of claims 1 to 36.

46. A kit of parts as claimed in any of claims 42 to 45 when used in a loft space conversion as claimed in any of i claims 37 to 39.