FIELD OF INVENTION

The present invention relates to the field of smoke reduction, and in particular to the reducing the spread of smoke during a fire.

BACKGROUND TO THE INVENTION

Roof decking, sometimes labelled a roof deck, is an element that spans between structural supports for a roof (e.g. between joists), and acts as an additional support for the roof. Roof decking may also be used, in a similar manner, to support a floor for a storey above the roof decking.

Roof decking is typically corrugated, forming troughs and peaks. Corrugation allows for expansion and contraction with different temperatures, improves ease of installation and provides greater strength, when compared to flat decking.

Commercial property, such as supermarkets, factories, warehouses, airports and the like, often make use of metallic roof decking for supporting roofs or floors. To improve acoustic performance, roof decking often comprises perforations or holes, which acts to absorb sound. Perforation of the roof decking may be full, web or span. Typically, these perforations are circular with a diameter of from 3mm to 5mm, e.g. between 3.3mm and 4.5mm.

To further improve acoustic performance of corrugated roof decking, acoustic infills or plugs can be placed within the troughs of the corrugated roof decking. These acoustic infills are usually trapezoidal in shape (to fit within the trough) and are formed of fibres, such as mineral wool or animal wool (e.g. sheep wool).

Acoustic infills also act to (at least partially) block up the perforations, to thereby prevent or hinder the passage of smoke through the roof decking.

SUMMARY OF THE INVENTION

The invention is defined by the claims. According to an aspect of the invention, there is provided a method of reducing the gas permeability of a corrugated roof decking comprising perforations designed for acoustic damping. The method comprises directly securing at least one perforation-blocking element to the corrugated roof decking, wherein the directly secured at least one perforation-blocking element covers the perforations to thereby reduce or block the passage of gas through the (covered) perforations.

The invention relies on the recognition that acoustic infills for existing corrugated roof decking are often missing (e.g. never installed), damaged (e.g. during installation) or inefficient at preventing toxic gas flow (e.g. due to imperfections in the acoustic infill or incorrect placement of the acoustic infill). This may result in roof decking permitting the flow of toxic gas, through the perforations designed for acoustic damping, in the event of a fire. As roof decking typically spans across an entire storey, including fire corridors or “escape routes” having gas impermeable walls, any gas permeability of the roof decking may allow toxic gases from outside a fire corridor to enter a fire corridor (by flowing via a roof spacing). Thus, toxic gases or smoke may enter an area otherwise gas-secured or isolated (e.g. via the walls and floor) therefrom.

The present invention proposes to reduce the gas permeability of a corrugated roof decking by directly securing or directly affixing a perforation blocking thereto. The perforation-blocking element reduces or blocks the passage of gas, such as toxic gases and/or smoke, through the perforations, thereby reducing the spread of smoke during a fire. In other words, the perforation-blocking element seals or secures the room/space below the roof decking from gases present or introduced into a space above the roof decking by reducing/preventing the passage of gas through perforations designed for acoustic damping.

The proposed method may be applied, for example, to roof decking in fire corridors, to act as a sealant against the ingress of toxic gases and/or smoke from outside the fire corridor into the fire corridor via the roof of the fire corridor. This improves the safety of the fire corridor.

In particular, once the roof decking of the fire corridor undergoes the disclosed method, so that the perforations are effectively blocked, the corridor effectively becomes an enclosed/sealed/isolated tunnel. The enclosed tunnel can thereby act as a means of escape for people and for emergency services to gain entry to the building.

It is appreciated that the application of a perforation-blocking element may reduce the acoustic performance of the corrugated roof decking. However, as fire corridors are typically only used in the event of an emergency, this is of minimal concern.

Use of the proposed perforation-blocking element also avoids the need to install additional elements, such as a false ceiling/roof, within a fire corridor (which might act as a barrier to toxic gases), thereby saving expense and construction difficulties.

Preferably, the method comprises directly securing one or more perforation blocking elements to the roof decking to cover all perforations of roof decking that spans between one wall and another wall of a room, thereby reducing or blocking the passage of gas through all perforations of the roof decking between the two walls. In other words, there may be wall-to-wall coverage of all perforations in the roof decking.

Put another way, the covered perforations may comprise all perforations in (a portion of the) roof decking that spans from one wall of a room to another wall of the room. This helps reduce the ingress of potentially toxic gases into the room.

In particularly preferable embodiments, the method may comprise directly securing one or more perforation blocking elements to corrugated roof decking so that all perforations, of any corrugated roof decking, exposed to a particular room are covered by the perforation blocking element(s), thereby reducing or blocking the passage of gas through all perforations, of any roof decking, exposed to the room. This embodiment further reduces the ingress of potentially toxic gases into said room.

This latter embodiment effectively completely seal a room or corridor from outside the room into the room via the roof/ceiling of the room.

The term“directly secured” is here used to mean that the perforation blocking element is attached or otherwise fixed to the corrugated roof decking so that attempted pulling (e.g. using a human level of strength) of the perforation-blocking element from the corrugated roof decking would not result in the two components coming apart. This is in contrast, for example, to well- known acoustic infills that are merely placed within the corrugated roof decking and can be readily removed from the roof decking.

Preferably, the step of directly securing the perforation-blocking element comprises adhering the perforation-blocking element to the corrugated roof decking. Adhering the perforation-blocking element increases an ease of directly connecting the perforation-blocking element to the corrugated roof decking, e.g. for application from a distance, and provides a suitably strong bond for direct connection.

Other methods of securing a perforation-blocking element to the corrugated roof decking could be employed. By way of example, a perforation blocking element may grip the perforations via a plug system. In other example, the perforation-blocking element may be secured to the roof decking via a rivet.

In some embodiments, the (or each) perforation-blocking element comprises an adhesive that contributes to the reducing or blocking of the passage of gas through the perforations.

Thus, the perforations may themselves be blocked by adhesive, so that the adhesive contribute to the blocking or reduction in the passage of gas through the perforations. In other words, rather than being covered by a sheet of metal or the like, the perforations may be directly filled in by adhesive (i.e. an adhering material). This increases an ease of applying the perforation-blocking element to the corrugated roof decking.

In other words, the perforation-blocking element may comprise or consist of a perforation-blocking adhesive, which may optionally suspend or carry one or more materials therein as will be explained below.

In embodiments, the perforation-blocking element comprises fibres suspended in the adhesive. Fibres help to secure the adhesive within the perforations, by increasing the strength of the set adhesive. The fibres also assist in blocking the perforations, e.g. by aligning themselves to block the perforations.

Preferably, the fibres suspended in the adhesive comprise heat-resistant fibres. Heat-resistant fibres include any fibres that retain their integrity when heated, i.e. without breaking down. This improves a performance of the perforation-blocking element, by providing additional heat or fire-resistant property. This means that the perforation-blocking element will remain in place for a longer period, without breaking down, during a fire, increasing a safety of the corrugated roof decking.

In embodiments, each of the fibres has a length of from 1 mm to 10mm, and preferably of from 2 mm to 5mm. In other or further embodiments, the length of the fibres may be greater than the diameter or width of each perforation.

Preferably, the fibres are sufficiently small so that at least some of them pass through the perforations, so that the adhesive can be secured on both sides of the roof decking. This improves the adhesion of the perforation- blocking element and increases the likelihood that the perforation-blocking element will cover the entirety of the perforation.

The fibres suspended in the adhesive comprise one or more of the following: glass fibres; mineral fibres; carbon fibres and ceramic fibres. These materials have been identified as being particularly helpful in acting as fire or heat resistant material.

The adhesive may be a sprayable adhesive. Accordingly, the step of directly securing the blocking element to the corrugated roof decking may comprise spraying the sprayable adhesive over the perforations of the corrugated roof decking.

Providing a sprayable adhesive increases the ease of applying the perforation-blocking element to the corrugated roof decking. In particular, a sprayable adhesive enables the perforation-blocking element to be applied from a distance. Such an embodiment thereby provides an easy to apply perforation-blocking element that can be applied even after the roof decking supports a floor or roof.

It will be apparent, from the foregoing, that the perforation-blocking element may (in its entirety) consist of a sprayable element, e.g. sprayable adhesive optionally carrying fibres.

The adhesive of the blocking element may be a fire-rated adhesive. A fire-rated adhesive improves the longevity of the perforation-blocking element in the event of a fire, maintaining the gas/smoke stopping properties of the perforation-blocking element for a greater period. In some embodiments, the step of directly securing the perforation blocking element comprises applying the perforation-blocking element from an underside of the corrugated roof decking.

As previously discussed, the present invention recognises that existing/extant roof decking may be gas permeable due at least to errors in (the installation of) the acoustic infill. Appling the perforation-blocking element to an underside of the corrugated roof decking allows this imperfection to be corrected without needing to lift or remove the roof/floor supported by the roof decking (e.g. to (re)install or replace the acoustic infill).

Adhesive-based perforation-blocking elements are particularly advantageous, as they provide a method of sealing the perforations from an underside of the roof decking.

The underside of the roof decking is the side of the roof decking that does not support the remaining components of the roof/floor, e.g. the side that face the space or room capped by the roof/floor. The upper side of the roof decking faces the roof/floor above (and faces away from the space/room capped by the roof/floor).

Preferably, the perforation-blocking element is heat-resistant.

In some embodiments, the perforation-blocking element may be designed to maintain its integrity for no less than a predefined number of minutes when exposed to a predefined temperature. Here, maintaining its integrity means that the perforation-blocking element continues to block the passage of smoke through the covered perforations for at least the predefined number of minutes when exposed to the predefined temperature.

The predefined number of minutes may be no less than 30 minutes, e.g. no less than 60 minutes, e.g. no less than 120 minutes, e.g. no less than 240 minutes. The predefined temperature may be no less than 200°C, e.g. no less than 400°C, e.g. no less than 600°C, e.g. no less than 1000°C.

For example, the perforation-blocking element may be designed to maintain its integrity for no less than 30 minutes when exposed to a temperature of at least 200°.

The skilled person would be readily capable of selecting appropriate materials and formulations to achieve these characteristics. Silicate-based materials or adhesives are particularly useful to meet these minimum requirements.

The perforation-blocking element may comprise an intumescent material. The intumescent material will swell or expand upon exposure to heat. This can act to increase a blocking capability of the perforation-blocking element, thereby improving the sealing effect of the perforation-blocking element, in the event of a fire.

The method is only performed when flooring or a roof is secured to the upper side of the corrugated roof decking. The invention is particularly advantageous in that it can be used to correct extant defects in roofs without needing to lift the roof/floor. Thus, there is a corresponding technical advantage in only using the proposed method when flooring or a roof is secured to the upper side. If no roof/flooring is secured to the upper side of the corrugated roof decking, then it would (under current economic conditions) be cheaper or simpler to install acoustic infills, which would have the advantage of improving acoustic performance and reducing gas permeability.

In an embodiment of the invention, there is proposed a method for reducing gas flow into a room via corrugated roof decking that comprises perforations designed for acoustic damping and is exposed to the room. The method comprises directly securing at least one perforation-blocking element to the corrugated roof decking, wherein the directly secured at least one perforation-blocking element covers all perforations of the corrugated roof decking that are open to the room to thereby reduce or block the passage of gas through the (covered) perforations.

A perforation is considered open to the room if gas is able to flow through the perforation to directly enter the room. In other words, the perforation spans from a side of the corrugated roof decking exposed to the room to an opposite side of the corrugated roof decking.

A room is any area having a ceiling or roof, in which the corrugated roof decking contributes to supporting at least part of the ceiling or roof.

There is provided a perforation-blocking element for reducing or blocking the passage of gas through perforations, designed for acoustic damping, of a corrugated roof decking, the perforation-blocking element comprising an adhesive for directly securing the perforation-blocking element to the corrugated roof decking, wherein the adhesive, when directly secured to the corrugated roof decking, contributes to the reducing or blocking of the passage of gas through the perforations.

The perforation-blocking element may therefore comprise perforation- blocking adhesive.

Preferably, the perforation-blocking element comprises fibres suspended in the adhesive. The fibres suspended in the adhesive may comprise heat-resistant fibres. In embodiments, each of the fibres has a length of from 1 mm to 10mm, and preferably of from 2 mm to 5mm. The adhesive of the blocking element may be a fire-rated adhesive. The adhesive is a sprayable adhesive.

According to another aspect of the invention, there is also provided the use of any herein described perforation-blocking element for covering perforations, designed for acoustic damping, of a corrugated roof decking to thereby reduce or block the passage of gas through the perforations. Preferably, this is only performed when flooring or a roof is secured to the upper side of the corrugated roof decking.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

Figure 1 illustrates an example of typical roof decking;

Figure 2 illustrates an example of typical roof decking with an acoustic infill;

Figure 3 illustrates a side view of a typical roofing system;

Figure 4 illustrates perforations of a typical roofing decking, the perforations being designed for acoustic damping;

Figure 5 illustrates roof decking undergoing a method according to a first embodiment of the invention;

Figure 6 illustrates roof decking undergoing a method according to a second embodiment of the invention; Figure 7 illustrates roof decking undergoing a method according to a third embodiment of the invention;

Figure 8 illustrates a perforation-blocking element for use in the third embodiment of the invention;

Figure 9 illustrates roof decking undergoing a method according to a fourth embodiment of the invention and

Figure 10 is a flow chart illustrating a method according to an embodiment of the invention. DETAILED DESCRIPTION

It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings.

The diagrams are purely schematic and it should therefore be understood that the dimensions of features are not drawn to scale. Accordingly, the illustrated thickness of any of the components or features should not be taken as limiting. For example, a first component drawn as being thicker than a second component may, in practice, be thinner than the second component.

It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts. Terms describing positioning or location (such as upper, lower, above, below, top, bottom, etc.) are to be construed in conjunction with the orientation of the structures illustrated in the diagrams.

According to a concept of the invention, there is proposed a method of preventing gases from passing from above a roof decking into a room or space below a roof decking via perforations in the roof decking. The method comprises sealing the roof decking, comprising perforations, to prevent gas from passing through the roof decking. The method comprises directly securing one or more perforation-blocking elements to the roof decking to thereby cover perforations and prevent gas from flowing through the covered perforations. Preferably, all perforations exposed to a particular room are covered by the one or more perforation-blocking elements.

Embodiments are at least partly based on the realisation that acoustic infills placed within corrugated roof decking are often missing, incorrectly installed or otherwise defective. Thus, the inventors have recognised a desire to prevent gases at an upper side of the roof decking from passing to a space below an underside of the roof decking. Rather than using additional constructional elements, such as a false roof, the present inventors have recognised that the perforations can be sealed using a directly secured perforation-blocking element to prevent the passage of gas.

Thus, the present invention enables the repair or renovation of latent defects in a roofing system, in order to meet smoke permittivity requirements or desires.

Illustrative embodiments may, for example, be employed in fire corridors to prevent the ingress of toxic gas or smoke into the fire corridor from a space outside the fire corridor (but sharing the same roof). Thus, the fire corridor can be gaseously isolated from rooms surrounding the fire corridor.

Figure 1 illustrates an example of typical roof decking 1.

The roof decking 1 is formed of corrugated material, and is typically metallic. Suitable examples include corrugated steel, iron, aluminium or tin. The corrugations of the roof decking 1 form troughs 2, formed of a base 2a and sidewalls 2b, and peaks 3.

The roof decking comprises perforations 5, which act to improve acoustic damping of the roof decking, e.g. reducing echoes that may otherwise cause reverberating of an underside of the roof decking. Here, the perforations 5 are formed in the sidewall 2b of the troughs 2. However, the perforations may be, additionally or otherwise, formed in other aspects of the roof decking 1 , e.g. the base 2a of the trough or in the peak 3.

Figure 2 illustrates the typical roof decking 1 with an acoustic infill 20 positioned within a trough 2. The acoustic infill 20 is inserted, from an upper side of the roof decking 1 , into the trough 2, to be supported by the roof decking.

The acoustic infill is not (directly) secured or otherwise (directly) affixed to the roof decking. The acoustic infill acts to further improve the acoustic damping of the roof decking, e.g. by absorbing sound passing through the perforations 5. The acoustic infill 20 at least partially blocks the perforations 5 by covering the perforations.

Figure 3 illustrates a (partially) exploded side-view of a typical roof system 30 comprising roof decking 1.

The roof system 30 comprises the roof decking 1 , with acoustic infills 20 inserted into its troughs.

A mineral fibre layer 31 , formed from mineral/synthetic fibre is disposed above the roof decking 1 , and may be secured thereto. The mineral fibre layer 31 acts as heat and sound insulation. The mineral fibre layer 31 may be omitted in some structures.

A vapor barrier layer 32, sometimes called a vapor protection barrier or simply vapor barrier, is disposed above the mineral fibre layer 31. The vapor barrier layer 31 performs damp proofing to prevent the ingress of water or vapor to the mineral fibre layer or the roof decking (i.e. into the building or between floors). A vapor barrier layer is typically formed from a plastic or foil sheet, although other materials are known in the art.

The roof system 30 further comprises a roof 33. The roof 33 acts as the uppermost barrier to the roof system, and usually exposed to the outside. The roof may be formed from a variety of materials, such as tiles, concrete or metal sheeting. Other suitable materials for a roof 33 will be well known to the skilled person. Typically the roof 33 is securing to the roof decking 1 , e.g. via one or more pins (not shown).

For the sake of clarity, the“upper side” of the roof decking 1 is the side most proximate to the vapour barrier layer 32, roof 33 or outside. The“lower side” or“underside” of the roof decking 1 is the side most distant from the vapour barrier layer 32, roof 33 or outside.

It has previously been explained how roof decking 1 may be used to support a floor (e.g. for another storey of the building). Thus, references to the term“roof” may be replaced in the above description by the term“floor of the storey above” where appropriate. Of course, a vapour barrier layer is not essential if the roof decking is used to support a floor.

Figure 4 illustrates the perforations 5 in the roof decking in detail. The perforations 5 are, as illustrated, usually circular with a diameter d of from 3mm to 5mm, e.g. between 3.3mm and 4.5mm. Other shapes for the perforations are also envisaged, e.g. oval, square, rectangular and so on.

The perforations 5 can be arranged in layers that are offset from one another. A typical distance s between a center of a perforation of an upper layer and a center of a most proximate perforation of an immediately lower layer is from 5mm to 8 mm, for example, around 6.5mm.

The precise size and placement of the perforations will differ between different roof deckings, and the above-identified sizes are merely given as appropriate examples.

Figure 5 illustrates a roof decking 1 undergoing a method according to a first embodiment of the invention, which method is only performed when flooring or a roof (not shown) is secured to the upper side of the roof decking 1.

The method comprises directly securing a perforation-blocking element 50 to the corrugated roof decking 1 , so that the directly secured perforation blocking element covers the perforations.

In the illustrated example, the perforation-blocking element is applied (i.e. secured to) the corrugated roof decking from an underside of the roof decking. This provides an advantage of increased ease in applying the perforation-blocking element to existing roof deckings (e.g. those already supporting a roof/floor).

Flere, the perforation-blocking element 50 is applied to the corrugated roof decking 1 by spraying a sprayable adhesive over the perforations 5. The sprayable adhesive directly secures itself to the roof decking, thereby blocking and filling the perforations. Thus, the sprayable adhesive 50 seals the (perforations of the) roof decking, to prevent or reduce (e.g. by an amount >80%) the passage of gas through the perforations 5. In other words, the adhesive itself may contribute to the blocking or filling of the perforations.

Thus, the perforation-blocking element may effectively be a perforation- blocking adhesive.

The spayable adhesive may be disposed by a spraying mechanism 55, e.g. a spray gun.

The skilled person would be readily capable of identifying adhesives suitable for spraying and for covering perforations, e.g. by selected an adhesive of suitable viscosity for spraying and strength for remaining homogenous when covering a perforation.

Suitable examples of appropriate adhesives include sodium silicate- based adhesives, polycholoprene, latex-based elastomeric sealants and so on. Sprayable adhesives may be labelled“gun-grade”. Preferably, the sprayable adhesive is one that hardens upon exposure to air or upon being sprayed, to prevent the sprayable adhesive from hardening prior to be being sprayed onto the roof decking.

The skilled person would also be capable of selecting appropriate spraying mechanisms 55, e.g. defining suitable nozzles sizes and hose sizes based on the characteristics of the sprayable adhesive. Thus, directly securing the perforation blocking element to the roof decking may comprise using the spraying mechanism 55 to spray the perforation blocking adhesive onto the roof decking.

Preferably, the adhesive of the blocking element is a fire-rated adhesive.

A fire-rated adhesive is an adhesive able to meet a certain fire-rating criteria, e.g. passes a fire test or fire-resistance test, which criteria may differ in different jurisdictions. In particular, the adhesive may be designed to maintain its integrity for no less than a predefined number of minutes when exposed to a predefined temperature. A more detailed explanation of the term “fire-rated” will be explained below, in the context of all embodiments.

To further improve the blocking or sealing of the perforations performed by the adhesive forming the perforation-blocking element, fibers 51 may be suspended in the adhesive 50. The fibers increase the strength of the adhesive, and may supplement the smoke-protection quality of the adhesive.

Preferably, each of the fibers has a length of from 1 mm to 10mm, and preferably of from 2 mm to 5mm. The fibers do not need to be a consistent size, e.g. they may be of different sizes or sizes distributed within the range. This allows the fibers to be sufficiently small that some will pass through the perforations, whilst others remain on the underside of the roof decking. This increases the fixedness or secureness of the perforation-blocking element to the roof decking.

In some examples, the fibers 51 suspended in the adhesive 50 comprise heat-resistant fibers, being fibers that retain their integrity even when heated (e.g. are“fire-rated”). This improves the heat-resistivity of the perforation blocking element and thereby improves the likelihood that the integrity of the perforation-blocking element will be maintained in the event of a fire (and thereby continue to block potentially toxic gases or smoke). Suitable examples of (heat resistant) fibers include: glass fibers; mineral fibers; carbon fibers and ceramic fibers.

The adhesive or perforation-blocking element may comprise intumescent material that expands upon exposure to heat. This means that, in the event of a fire, the intumescent material will expand and increase an efficacy in blocking of the perforation. The intumescent material may also be suspended in the adhesive.

Intumescent materials are well known to the skilled person, and typically comprise one or more epoxies.

Rather than spraying the adhesive (which may involve atomizing or nebulizing the adhesive), the adhesive may be applied via a (pressured) hose mechanism. Hosing and spraying the adhesive share a same concept of applying the adhesive in liquid form via a (directable) nozzle. This shared concept enables for easy application of the perforation-blocking element from a distance.

Preferably, the pressure of the spray or hose is extremely low, e.g. 10psi or less, to increase the likelihood that the adhesive will adhere or fall onto the material surrounding the perforations. Thus, the step of directly securing at least one perforation-blocking element to the corrugated roof decking may comprise applying perforation-blocking adhesive in a liquid form via a nozzle at a pressure of no more than 10psi, e.g. no more than 5psi.

Other methods of applying or directly securing the perforation-blocking element, described above, to the roof decking will be apparent to the skilled person.

For example, the perforation-blocking element may be troweled or otherwise applied by hand, i.e. manually, onto the roof decking. A troweled adhesive enables the perforation-blocking element to be applied onto hard-to- reach places (e.g. around a corner, where a spray nozzle may not fit). In other examples, one or more rollers may be used. It will be appreciated that, in such embodiments, the adhesive does not to be sprayable (but may otherwise have the same characteristics as any previously described embodiment).

Each of these methods shares a same step of directly securing (via adhesive) the perforation-blocking element (which here comprises the adhesive itself) to the (underside of the) roof decking.

It is conceivable, but not essential, that the method according to the first embodiment may further comprise a step of applying additional material to the applied adhesive. By way of example, intumescent material or an intumescent coating/paint may be applied over the adhesive (e.g. via another spray), which may improve the blocking functionality in the event of a fire (as the intumescent material will expand). As another example, colored paint may be applied to the applied adhesive to improve an aesthetic appearance of the treated roof decking.

Figure 6 illustrates a roof decking 1 undergoing a method according to a second embodiment of the invention, which method is only performed when flooring or a roof (not shown) is secured to the upper side of the roof decking 1 .

In the second embodiment, a perforation-blocking element 60 comprises a sheet 61 (e.g. of metal, plastic or other gas-blocking material) for blocking the perforations and securing means 62 for directly securing the sheet 61 to the decking 1 , so that the overall perforation-blocking element 60 is directly secured to the roof decking.

Flere, the securing means 62 comprises adhesive, so that the sheet 61 is adhered to the roof decking. Thus, the method may comprise applying adhesive 62 (to an underside of the roof decking) around the perforations, then applying the sheet 61 to the adhesive 62 to thereby block the perforations. In this way, a perforation-blocking element 60 is directly secured to the roof decking.

Although illustrated in a continuous line, the adhesive 62 may instead be applied sporadically over the underside of the roof decking. The adhesive 62 may be applied in between the perforations, instead of or in additional to outside the perforations as illustrated, to improve a secureness of the sheet 61 to the roof decking. The sheet 61 may comprise a sheet of intumescent material, to improve the smoke-sealing effect of the perforation-blocking element 60 in the presence of a fire or heat.

Other securing means 62 may be employed by the skilled person, for example, rivets or via a gripping element that grips either side of a perforation to directly secure the perforation-blocking element 60 to the roof decking 1.

Figure 7 illustrates a roof decking undergoing a method according to a third embodiment of the invention, which method is only performed when flooring or a roof (not shown) is secured to the upper side of the roof decking 1 .

In the third embodiment, a perforation-blocking element 70 comprises one or more plugs of material that secure the perforation-blocking element within one or more perforations.

By way of example, and as illustrated, a plug of material 70 may be insertable into a single perforation to thereby block the perforation. The plug is secured within the perforation on either side by a respective roundel of material 70A, 70B (which are connected by a thinner member 70C). One of the roundels 70B may be tapered to ease insertion into a perforation.

The method according to the third embodiment comprises directly securing the perforation-blocking element to the roof decking by inserting the plug of material 70 (forming the perforation-blocking element) into a perforation.

Other shapes and sizes for the perforation-blocking element will be apparent to the skilled person.

Preferably, the material forming the perforation-blocking element comprises an intumescent material that expands upon exposure to heat. This increases the effectiveness of the perforation-blocking element when there is a fire (i.e. and toxic gases and/or smoke are present).

The plugs may also act as acoustic absorbers, thereby improving an acoustic performance of the treated roof decking (compared to other embodiments of the invention).

Figure 8 illustrates another perforation-blocking element 80 for use in the third embodiment.

The perforation-blocking element 80 comprises a sheet of material 81 that spans across, or is sized to block, more than one perforation. The sheet of material 81 is connected to one or more plugs 82 for insertion into a respective one or more perforations.

Thus, the sheet of material 81 is secured to the roof decking by inserting the plug(s) into the perforation(s). When securing to the roof decking, the sheet of material covers one or more perforations, and preferably a plurality of perforations, to thereby prevent gases from flowing through the covered perforations.

The plugs may be replaced by any other suitable securing means, e.g. in the manner of the second embodiment previously described.

The sheet of material 81 may be formed in an identical or similar manner to the sheet 61 of the second embodiment, e.g. from similar/identical materials.

The previously illustrated embodiments show the preferred scenario of directly securing the perforation-blocking element(s) to the roof decking by applying the perforation-blocking element to the underside (i.e. the side facing away from the roof/outside/upper floor) of the roof decking. In particular, the illustrated embodiments comprise securing the perforation-blocking element(s) to the underside of a sidewall of a trough formed by the corrugated roof decking.

Although preferred, it is not essential to apply the perforation-blocking element(s) to the underside of the roof decking.

Figure 9 illustrates a modified version of the embodiment illustrated by

Figure 5, in which the perforation-blocking element 90 is applied to the corrugated roof decking 1 by spraying a sprayable adhesive over the perforations 5. Thus, Figure 9 illustrates a method according to a fourth embodiment of the invention.

Rather than applying the perforation-blocking element 90 from an underside of the corrugated roof decking (as illustrated in Figure 5), the perforation-blocking element is applied from inside the trough of the corrugated roof decking (i.e. from inside the roof decking).

This process may comprise using a spraying mechanism 95, e.g. a spray gun, to apply the sprayable adhesive 90. Examples of suitable sprayable adhesives, and optional fibers 91 be suspended in the adhesive 90 have been previously described.

The spraying mechanism may, for example, be pulled through the trough of the corrugated roof decking (e.g. at a predetermined rate) to spray the sprayable adhesive over the perforations. The rate of spraying/dispersal of the sprayable adhesive may be known, so that a correct calculation of the rate at which the spraying mechanism is pulled through the roof decking can be predetermined.

The skilled person will appreciate how the other previously described methods for applying a perforation-blocking element to an underside of the roof decking can be appropriately modified for application from within the roof decking.

All the above-described embodiments disclose concepts for directly securing a perforation-blocking element to the corrugated roof decking, wherein the directly secured perforation-blocking element covers the perforations to thereby reduce or block the passage of gas through the perforations.

In any above-described embodiment, the perforation blocking element may be fire or heat-resistant. In particular, the perforation-blocking element may be designed to maintain its integrity for no less than a predefined number of minutes when exposed to a predefined temperature.

Here, maintaining its integrity means that the perforation-blocking element continues to block/reduce (e.g. by no less than 80%) the passage of smoke through the perforations that the perforation-blocking element covers, for the duration of the predefined number of minutes, to at least the same level/magnitude as at the start of the exposure to the predefined temperature.

It is possible to test whether a material or perforation blocking element meets this criteria by, for example, placing a sample roof decking (having perforations designed for acoustic damping) to which the perforation blocking element has been applied (“treated roof decking’’) in a kiln.

The kiln can then be heated to the predefined temperature, and a sensor or sensors, e.g. a camera or flow sensor, can detect the flow of smoke or gases with the kiln and in particular through the covered perforations of the roof decking. This could be performed, for example, by injecting/circulating detectable gas into the kiln (e.g. CO ₂ ), and filming the flow of the detectable gas. The sensor may be able to detect when there is a reduction in the blocking of the perforation-blocking element, and therefore when the integrity of the perforation blocking element begins to break down. Alternatively, the flow of gas through the perforations (i.e. has permeability) of the treated roof decking may be tested before the roof decking is placed in the kiln. The kiln can then be heated to the predefined temperature and held at that temperature for the predefined number of minutes. The treated roof decking may then be removed from the kiln, and the flow of gas through the perforations can be retested, to see whether the material has retained its integrity during exposure to the kiln.

Other methods of testing the integrity of a perforation-blocking element will be apparent to the skilled person.

The predefined number of minutes may be no less than 30 minutes, e.g. no less than 60 minutes, e.g. no less than 120 minutes, e.g. no less than 240 minutes. The predefined temperature may be no less than 200°C, e.g. no less than 400°C, e.g. no less than 600°C, e.g. no less than 1000°C.

One example of a suitable material for a perforation blocking is a silicate- based epoxy adhesive, such as a calcium silicate based material, which has a continuous operating temperature of up to 1250°C.

Preferably, the perforation-blocking element passes one or more Fire Test“L Ratings” (typically at 400°F) for smoke leakage, which rating can be is found in standard UL/ANSI 1479 or CAN/ULC S 115 (amongst others).

In some embodiments, the perforation-blocking element may also be designed to prevent the flow of fire through the roof decking. In particular, the perforation-blocking element may be designed to prevent the flow of fire having a second predefined temperature for a second predefined number of minutes.

In particular examples, the perforation-blocking element may meet on or more fire test“F Ratings”, which rating can be is found in standard ASTM E814, UL/ANSI 1479 or CAN/ULC S1 15 (amongst others).

The second predefined number of minutes may be no less than 30 minutes, e.g. no less than 60 minutes, e.g. no less than 120 minutes, e.g. no less than 240 minutes. The second predefined temperature may be no less than 200°C, e.g. no less than 400°C, e.g. no less than 600°C, e.g. no less than 1000°C.

The skilled person would be readily capable of selecting appropriate materials and substances for forming the perforation blocking element that meet these requirements. Figure 10 is a flow chart illustrating a method 100 according to an embodiment of the invention. The method 100 reduces the gas permeability of a corrugated roof decking comprising perforations designed for acoustic damping. The method 100 comprises a step 101 of directly securing at least one perforation-blocking element to the corrugated roof decking, wherein the directly secured perforation-blocking element covers the perforations to thereby reduce or block the passage of gas through the perforations.

Embodiments also extend to the use of any herein described perforation-blocking element for covering perforations, designed for acoustic damping, of a corrugated roof decking to thereby reduce or block the passage of gas through the perforations.

In some embodiments, the roof decking spans from one wall to another wall (of a particular room). The process of securing one or more perforation blocking elements may comprise covering or blocking all perforations, of the roof decking, that are exposed to the room, e.g. all perforations that are between the two walls between which the roof decking spans.

Preferably, embodiments of the invention comprise securing one or more perforation blocking elements to any roof decking exposed within a room to thereby cover or block all perforations exposed to or in said room. This embodiment further reduces the ingress of potentially toxic gases into said room.

Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. If the term "adapted to" is used in the claims or description, it is noted the term "adapted to" is intended to be equivalent to the term "configured to". Any reference signs in the claims should not be construed as limiting the scope.