A METHOD AND APPLICATOR FOR TREATING AN EXTERNAL SURFACE OF A ROOF

Abstract

 A method of treating an external surface of a roof, such as the external surface of a roofing membrane, to enhance fire performance, the method comprising the steps of: applying to the exterior of the roofing membrane a flexible fibrous barrier, and a fire retardant composition which is flowable, for example in a liquid form, wherein the barrier comprises a flexible layer of fibrous material; so that the flexible fibrous barrier is impregnated with the fire retardant composition; and allowing the composition to cure and/or dry. Also disclosed is an applicator trolley for applying a flexible barrier to an external surface of a roof, such as the external surface of a roofing membrane, to enhance fire performance, the applicator comprising:
(a) a wheeled frame,
(b) a holder on the frame, the holder for holding a roll of flexible fibrous material,
(c) a dispenser on the frame, the dispenser for dispensing the flexible fibrous material from the roll onto the external surface of the roof.

Description

Field of the Invention

[0001] In particular the present invention is concerned with improving the fire properties of a roof. In particular the present invention may improve the fire retardancy of a roof. The present invention relates to a method of treating an external surface of a roof. The invention also relates to a device for allowing such treatment of the external surface of a roof.

Background to the Invention

[0002] It is always desirable to have good fire properties in construction materials so that the damage caused by fire and the ignition and/or spread of fire are all minimised.

[0003] For example, approaches have been adopted to improve the fire retardancy of thermal insulation products, such as foam boards. One way to decrease the flammability of such products is to decrease the flammability of the foam by incorporating fire retardant additives into the compositions used to form the foams.

[0004] Another method for reducing the flammability of closed cell thermal insulation foam products such as such as polystyrene including expanded polystyrene or extruded polystyrene, polyisocyanurate, polyurethane or phenolic foam products, is to employ blowing agents having low flammability. While chlorofluorocarbons and hydrochlorofluorocarbons have low flammability, their use has also been phased out following the Montreal Protocol, because of the global warming potential and ozone depletion potential of such substances. Hydrocarbon blowing agents have reduced environmental impact, but the thermal insulation and fire performance of hydrocarbon blowing agents less favourable. Hydrofluoroolefin blowing agents such as 1233zd have excellent fire retardancy and thermal insulation performance and their use as blowing agents in thermoset and thermoplastic insulation products is already prevalent.

[0005] Such approaches and like approaches typically depend on action being taken at the time the construction material is being manufactured.

[0006] It is also desirable, however, to provide solutions which allow for retrofitting. Such retrofitting can be used to improve the fire properties of a construction article such as a roof which has already been incorporated into a construction structure.

Summary of the Invention

[0007] In one aspect, the present invention provides a method of treating an external surface of a roof, such as the external surface of a roofing membrane, to enhance fire performance, the method comprising the steps of:

applying to the exterior of the roofing membrane a flexible fibrous barrier, and a fire retardant composition which is flowable, for example in a liquid form, wherein the barrier comprises a flexible layer of fibrous material; so that the flexible fibrous barrier is impregnated with the fire retardant composition; and

allowing the composition to cure and/or dry.

[0008] The present invention thus provides a solution which allow for retrofitting. Such retrofitting can be used to improve the fire properties of a construction article such as a one forming at least part of a roof (i.e. a construction article which has already been incorporated into a construction structure such as a roof).

[0009] The roofs in question are typically flat roofs for example those with a pitch of up to 10°.

[0010] The present invention is particularly useful with roofing membranes such as those used on flat roofs. The membranes in question are those which form a waterproof barrier on a roof. Typically such membranes are the outermost part of the roof and they have an external surface i.e. the external surface of a roof. Such membranes are often the weatherproof external layer of a roof. The present invention thus provides a solution which allow for retrofitting to such roofing membranes. Such retrofitting can be used to improve the fire properties of a roofing membrane forming at least part of a roof.

[0011] Furthermore, the present invention is in particular useful for an external surface of a roof, such as an external surface of a roofing membrane, which lies underneath or proximate an energy capturing product such as a solar energy capturing device, for example a photovoltaic device such as a photovoltaic panel.

[0012] The present invention thus prides enhanced fire properties which are useful where there is an installation of an energy capturing device such as a solar energy capturing device, for example a photovoltaic device such as a photovoltaic panel on the roof.

[0013] In particular if there is an overheating or other fire hazard event with the energy capturing device the present invention protects the adjacent external surface of the roof.

[0014] Of the roofing membrane types with which the present invention may be utilised, these include those constructed of one or more layers of one or more of the following materials: EPDM (ethylene propylene diene monomer), TPO (thermoplastic polyolefin), PVC (polyvinyl chloride), KEE (ketone ethylene ester), SBS (styrene butadiene styrene), APP (atactic polypropylene), bitumen including modified bitumen, sprayed foams, such as rigid closed cell sprayed foams, such as a rigid closed cell sprayed polyurethane foam (typically with a protection layer on top of the foam such as an elastomeric layer).

[0015] The method of the invention may comprise the step of adhering the flexible fibrous barrier to the external surface of the roof such as to the external surface of the roofing membrane. This is a useful step to allow the barrier formed by the method of the invention to be securely adhered to the roof, for example to the external roofing membrane.

[0016] The fire retardant composition may form a fire retardant coating.

[0017] For example the fire retardant composition may adhere to the external surface of the roof, for example to the external roofing membrane.

[0018] In order to promote such adhesion the step of applying adhesive promoter to promote adhesion of the fire retardant composition to the external surface of the roof, for example to the external roofing membrane, may be employed.

[0019] In order to promote such adhesion the step of applying adhesive to adhere the flexible fibrous barrier to the external surface of the roof, for example to the external roofing membrane, may be employed.

[0020] The adhesive promoter and/or the adhesive may be applied to the external surface of the roof, for example to the external roofing membrane, and/or the flexible fibrous barrier as the flexible fibrous barrier is applied to the external surface of the roof, for example to the external roofing membrane.

[0021] The fire retardant composition is flowable, desirably in a liquid form, and is suitably applied to the flexible layer of fibrous material as the flexible layer of fibrous material is being applied to the external surface of the roof, for example to the external roofing membrane.

[0022] Such methods allow for application of the flexible fibrous barrier to the external surface of the roof in one pass over the external surface of the roof. The flexible layer of fibrous material and the fire retardant composition can thus be combined in a one pass action. The flexible fibrous barrier and fire retardant composition are separate to each other and they are applied to the external surface of the roof at the same time.

[0023] It will be appreciated that the fire retardant composition can be applied more than one time. For example the fire retardant composition could also be applied so that it is on opposing sides of the flexible fibrous barrier. This assist with impregnation of the composition into the barrier. So it could be applied directly to opposing sides of the flexible fibrous barrier. The fire retardant composition could also be applied to the surface, the flexible fibrous barrier is then applied onto/into fire retardant composition and then the fire retardant composition could be applied to the opposite side of the flexible fibrous barrier.

[0024] The fire retardant composition may be applied, for example by spraying or pouring.

[0025] Optionally, the flexible layer of fibrous material can be applied onto the applied fire retardant composition as the fire retardant composition is applied. In this way there is a continuous application of both the flexible layer of fibrous material and the fire retardant composition at the same time. As above the fire retardant composition can, if desired, also be applied to the opposing side of the flexible layer of fibrous material in such a continuous manner.

[0026] It may be desirable to continuously apply the fire retardant composition and then immediately thereafter apply the flexible layer of fibrous material to the fire retardant composition. For example the flexible layer of fibrous material may be pressed onto the fire retardant composition so that the pressing action assists with impregnation of the flexible layer of fibrous material with the fire retardant composition.

[0027] The method of the invention may include using a screed, for example a flexible screed, such as a polymeric, e.g. rubber, screed to spread the fire retardant composition. This is advantageous as ensuring a good distribution of fire retardant composition is important for its fire properties to be imparted over a desired area. For example the screed may spread the fire retardant composition across the external surface of the roof or across the flexible layer of fibrous material. The screed may allow for even spread of fire retardant composition. Using a screed may assist with enhancing the strength of the cured retardant composition, for example a coating formed by it.

[0028] The method of the invention may include using a roller to tension the flexible layer of fibrous material so that it can be held taut as it is applied to an external surface of a roof, such as the external surface of a roofing membrane.

[0029] The roofing membrane is desirably at least one of a PVC membrane, an EPDM (ethylene propylene diene monomer) membrane or a bituminous membrane.

[0030] The fire retardant composition may be a two-part composition and the method may comprise mixing the two parts of the composition. In particular where the fire retardant composition is curable it may be desirable to maintain it in two separate parts to prevent cure.

[0031] It will be appreciated that an applicator comprising a roller and/or a screed and/or a dispensing head such as a spray head for dispensing the fire retardant composition may be utilised in a method of the invention.

[0032] The applicator may be in the form of an applicator trolley of the

[0033] The present invention also provides an applicator trolley for applying a flexible barrier to an external surface of a roof, such as the external surface of a roofing membrane, to enhance fire performance, the applicator comprising:

(a) a wheeled frame,

(b) a holder on the frame, the holder for holding a roll of flexible fibrous material,

(c) a dispenser on the frame, the dispenser for dispensing the flexible fibrous material from the roll onto the external surface of the roof.

[0034] The applicator trolley may further comprise a dispensing head for dispensing a fire retardant composition. In this way both the flexible fibrous material, for example a layer of same, may be laid down at the same time as the fire retardant composition. It will be appreciated that a multiplicity of dispensing heads or nozzles may be employed for even distribution of applied composition.

[0035] The dispensing head may be a spray head. Where desirable the dispensing head may move, for example in a reciprocating over and back action, to apply fire retardant composition over an area.

[0036] Optionally the trolley comprises a mixer for mixing two parts of a two-part fire retardant composition. A two-part composition maybe desirable where the fire retardant composition is curable. Cure can then then be initiated by mixing the two parts.

[0037] The mixer for mixing two parts of a two-part fire retardant composition may be attached to a dispensing head for dispensing a fire retardant composition. In this way a two-part composition can be mixed just before entering the dispensing head.

[0038] It will be appreciated that the applicator trolley of the invention may be adapted to continuously apply a fire retardant composition and then immediately thereafter apply the fibrous material, for example a flexible layer of fibrous material, to the fire retardant composition.

[0039] An applicator trolley of the invention may comprise urging means to cause a pressing action to press the fibrous material onto dispensed fire retardant composition so that the pressing action assists with impregnation of fibrous material with dispensed fire retardant composition. This is a simple method of combing the fibrous material and the fire retardant composition.

[0040] Suitably the urging means comprises a roller such as a spiked roller, for example a spiked roller where the spikes are resiliently deformable. This provides a simple way of applying pressure.

[0041] The applicator trolley may further comprise a screed, for example a flexible screed, such as a polymeric, e.g. rubber, screed to spread a fire retardant composition. This screed assists with a smooth finish and/or even spread in particular of the fire retardant composition. Using a screed may assist with enhancing the strength of the cured retardant composition, for example a coating formed by it.

[0042] The applicator trolley may be adapted to hold and dispense a web of the flexible fibrous material. This allows for ease of laying down a layer of fibrous material.

[0043] It will be appreciated that an applicator trolley of the invention may have one or more controls for controlling the speed at which it travels, the amount of fire retardant dispensed, the area covered etc.

[0044] The invention also relates to a roof structure, in particular one comprising a roof membrane and to which a flexible fibrous material and fire retardant composition have been applied. The roof structure may have equipment such as solar energy collection devices provided thereon and the barrier formed by the flexible fibrous material and fire retardant composition is between the equipment and the roof.

[0045] The roof or roofing structure may be thermally insulated for example using one or more foams. For example the membrane may be attached to the foam insulating material.

[0046] Foams that may be employed include polystyrene foams such as expanded polystyrene (EPS) foam or extruded polystyrene (XPS) foam. The density of such foams may be from about 10 kg/m³ to about 35 kg/m³, preferably from about 15 kg/m³ to about 25 kg/m³, and/or the compressive strength may be from about 5 to about 500 kPa, preferably from about 40 to about 200 kPa, and/or the thermal conductivity may be from about 0.040 to 0.030 W/m·K. Suitable EPS foams are commercially available from Kingspan under the tradename Unidek EPS or Aeroboard^®. Suitable, XPS foams are commercially available from Kingspan under the tradename Styrozone^®.

[0047] Foams that may be employed include polyurethane foam or polyisocyanurate foams. The density of such foams may be from about 10 kg/m³ to 60 kg/m³, preferably from about 25 kg/m³ to 35 kg/m³, and/or the compressive strength may be from about 50 to 300 kPa, preferably from 100 to 200 kPa, and/or the thermal conductivity may be from about 0.020 to 0.026 W/m.K. Suitable polyisocyanurate foams are commercially available from Kingspan under the tradename Therma^™.

[0048] Foams that may be employed include phenolic foams. The density of such foams may be from about 10 kg/m³ to about 100 kg/m³, suitably, from about 20 kg/m³ to about 60 kg/m³, more suitably, from about 25 kg/m³ to about 45 kg/m³, and/or the compressive strength may be from about 50 to 300 kPa, preferably from 80 to 150 kPa, and/or the thermal conductivity may be from about 0.015 W/m·K to 0.0250 W/m·K. Such phenolic foams are commercially available from Kingspan under the tradename Kooltherm^®.

[0049] Such foams may comprise a blowing agent that is fire retardant and/or a fire retardant component such as a brominated fire retardant and/or a polymeric fire retardant.

[0050] The fire retardant composition may be a curable phosphate composition. It may be applied in curable form and then cured.

[0051] The flexible fibrous barrier may be a glass fibre scrim, optionally wherein the glass fibre scrim is capable of reducing the pH of demineralised water having a pH of 7 to a pH 6.3 or lower, when assessed in accordance with ISO 3071:2005. Optionally said barrier has a thickness of at least 1 mm.

[0052] The curable composition may comprise:

a phosphate selected from the group consisting of: phosphoric acid,

phosphoric acid salts and combinations thereof,

a metal oxide, a metal silicate, and water,

where the weight ratio between the phosphate and the metal oxide is between about 3:1 and 1:1.

[0053] Advantageously, the combination of a glass fibre scrim capable of reducing the pH of demineralised water having a pH of 7 to a pH 6.3 or lower, when assessed in accordance with ISO 3071:2005, with the cured phosphate composition provides an effective, light-weight, fire resistant barrier. This barrier may be used to improve the fire performance of substrates to which it is attached.

[0054] The phosphate may be present in an amount of from about 10 to about 45 weight percent based on the total weight of the curable composition.

[0055] The metal oxide may be present in an amount of from about 5 to about 35 weight percent based on the total weight of the curable composition.

[0056] The metal silicate may be present in an amount of from about 1 to 15 weight percent based on the total weight of the curable composition.

[0057] The phosphate is preferably mono-potassium phosphate.

[0058] The metal oxide may be magnesium and/or calcium oxide. Preferably, the metal oxide is magnesium oxide.

[0059] The curable composition may be a two-part (2K) composition.

[0060] The phosphate and the metal oxide may be in separate parts of the two-part composition. Advantageously, this increases the shelf-life of the curable composition, and consequently, less curable composition is required to form an effective fire-resistant barrier.

[0061] The curable composition may further comprise a silica containing compound.

[0062] Optionally, the curable composition comprises mono potassium phosphate in an amount of from about 24 to about 32 weight percent, magnesium oxide in an amount of from about 22 to 28 weight percent, aluminium silicate or calcium silicate in an amount of from about 2 to 5 weight percent, and water in an amount of from about 20 to 40 weight percent, based on the total weight of the curable composition.

[0063] The curable composition may further comprise an adhesion promoter, for example, the curable composition may comprise an alcohol such as ethanol, propanol, butanol or isomers thereof. The adhesion promoter may be isopropanol, ethanol, ether, sodium silicate, limonene, an acrylic-styrene based co-polymer or combinations thereof. Preferably, the adhesion promoter is an acrylic-styrene based co-polymer. Suitably, the adhesion promoter comprises an aqueous emulsion comprising an acrylic-styrene based copolymer. The adhesion promoter may be present in an amount of from about 0.01 wt% to about 5 wt% based on the total weight of the curable composition.

[0064] The curable composition may comprise 20 to 35 wt% water based on the total weight of the curable composition, for example about 25 wt%.

[0065] The curable composition of the invention may be provided in a dry form. The only component that needs to be added later is water, for example just before application. The composition can then be mixed to form a liquid form for application. A surface to which the flexible fibrous barrier may be attached may be pre-treated with such an adhesion promoter, prior to application of the barrier to the substrate. Pre-treatment with the adhesion promoter may be achieved by application of the adhesion promoter by pouring, rolling, or spraying the adhesion promoter on said surface. Preferably, the adhesion promoter is sprayed onto the surface. Advantageously, the use of an adhesion promoter increases the strength of the attachment of the curable composition to a surface to which it is applied.

Brief Description of the Drawings

[0066] Embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a perspective view from one side of an applicator trolley of the invention, which is in use, and is applying, utilising the method of the invention, a flexible fibre barrier and a fire retardant composition to form a flexible fibrous barrier and applying the flexible fibrous barrier to an external surface of the roof;

Figure 2 is a perspective view from the same side but from behind the applicator trolley of Figure 1 - the applicator trolley being in use as in Figure 1; and

Figure 3 is a perspective view of a part of the applicator trolley of Figure 1 showing in particular a roller which tensions the flexible fibrous barrier and also showing a screed for spreading a fire retardant composition.

Detailed Description of the Drawings

[0067] Shown in the attached Figures 1 to 3 is an applicator trolley 1 of the invention. Figure 1 is a perspective view from one side of an applicator trolley 1 of the invention, which is in use. Figure 2 is a perspective view from the same side but from behind the applicator trolley of Figure 1 showing a better of view of dispensing of fire retardant composition. Figure 3 is a perspective view of a part of the applicator trolley 1 of Figure 1 showing in particular a roller 60 which tensions the flexible fibrous barrier and also showing a screed 70 for spreading a fire retardant composition.

[0068] The applicator trolley 1 is shown in use applying to the external surface of a roof 2 a flexible fibrous barrier 3. The applicator trolley is utilising a method of the invention. The external surface of the roof 2 is the external surface of a roofing membrane.

[0069] The applicator trolley 1 has a frame 10. The frame 10 comprises a series of frame members including side (horizontal) frame members 11. Transverse frame members 12 join the side frame members together. Opposing inclined upright frame member 13 (one on each side of the trolley) join to the side frame members 11 on opposing sides of the applicator trolley 1. A handle 14 extends transversely between opposing top ends of inclined upright frame members 13. The handle 14 can be used for steering the trolley 1.

[0070] A control panel 15 is provided on a transverse frame member 12. The control panel 5 includes switches/controls 16.

[0071] Opposing wheels 17 are provided on the trolley 1 thus providing a wheeled frame. A wheeled frame within the context of the present invention includes any rolling configuration e.g. where one or more rollers are used in place of wheels.

[0072] As is desirable for all embodiments (controlled) motorised movement of the trolley 1 is provided. Desirably this is an electrically powered motor which may be powered from mains electricity or battery. In the embodiment the motorised movement is provided by a motor 18 mounted on the frame 10 which drives at least one of the wheels 17.

[0073] The motorised movement (e.g. speed, start/stop) is controlled from the control panel 15 utilising one of the switches/controls 16.

[0074] A holder 20 is provided on the frame 10. The holder 20 is for holding a roll 21 of flexible fibrous material 22. It will be noted that the roll 21 is held transversely across the frame so that a web 23 of the flexible fibrous material 22 can be held on the trolley 1.

[0075] In this way the trolley 1 is adapted to hold and dispense a web 23 of the flexible fibrous material 22.

[0076] The applicator trolley 1 further comprises a dispensing head in the form of a spray head or nozzle 30. The nozzle 30 is for dispensing a fire retardant composition. In the embodiment a spray jet 31 of fire retardant composition is being dispensed.

[0077] As is desirable for all embodiments, the dispensing head, in the form of a spray head or nozzle 30, is not static and is moved to dispense fire retardant composition evenly across the external surface of the roof. For all embodiments this may be achieved using a reciprocating action which moves (transversely) the dispensing head over and back. An actuator such as an electrical, pneumatic or hydraulic actuator may be used. In the embodiment shown an electrical actuator 32 carries a carriage 33 which in turn carries the head or nozzle 30. The carriage 33 may be moved back and forth across the trolley 1 due to the reciprocating action of the actuator 32.

[0078] The movement (e.g. speed, start/stop) of the actuator 32, and thus also the movement of the carriage 33 and head or nozzle 30, is controlled from the control panel 15 utilising one of the switches/controls 16. In this way the distribution of the fire retardant composition to the eternal surface of the roof 2 can be controlled.

[0079] As is desirable for all embodiments, the dispensing head is fed with a supply of fire retardant composition. For such a configuration the fire retardant composition is flowable, for example in liquid form.

[0080] The fire retardant composition may be pumped through the dispensing head by a pump that is on the trolley. Alternative the pump may be separate from the trolley but feeds the trolley through one or more feed lines from the pump to the dispensing head.

[0081] If the fire retardant composition is a two-part composition then it is desirable that a mixer is provided to mix the parts.

[0082] In the embodiment a pump 40 is provided separately to the trolley 1. As the fire retardant composition being used is a two-part composition two pumps 40 each supply one of the separate parts of the composition though separate feed lines 41.

[0083] As is desirable for all embodiments separate control of the supply of each part of a two part composition allows for different mixing ratios as it may be desirable to adjust a mixing ratio for different compositions or simply for different cure rates where the fire retardant composition is curable. This is achieved with separately controllable supply of each of the parts of the composition which in the embodiment is in the form of separately controllable pumps 40.

[0084] At the start of the lines 41 the pumps 40 are fed by separate feed funnels 42.

[0085] At the end of the lines 41 is a mixer 43 for mixing two parts of the two-part fire retardant composition. The mixer 43 is attached to the dispensing head 30 for dispensing a fire retardant composition. The separate lines 41 feed the mixer 43 though separate ports. The mixer 43 has a single outlet for the dispensing head 30. So the mixer 43 combines the two separate supplies. This may be achieved by having two supply passages which merge into one outlet passage. The mixer may be configured, for example with internal convolutions and/or baffles to impart turbulent flow and thus assist mixing.

[0086] It will be appreciated that the mixer 43 (and the lines 41 that feed it) reciprocate with the dispensing head 30.

[0087] Accordingly a continuous supply of the two parts of the compositions is fed to the dispenser 30 in a mixed condition and thus the dispensed jet 31 of fire retardant composition is the desired ratio of combined parts dispensed at a desired rate. The applicator trolley is adapted to continuously apply the fire retardant composition.

[0088] Immediately after the fire retardant composition is applied the applicator trolley of the invention applies the fibrous material, for example a flexible layer of fibrous material, onto the fire retardant composition.

[0089] As mentioned above a holder 20 is provided on the frame 10. The holder 20 is for holding a roll 21 of flexible fibrous material 22. The roll 21 is held transversely across the frame so that a web 23 of the flexible fibrous material 22 can be held on the trolley 1.

[0090] The dispensing action (turning) of the roll 21 is controlled by roller bearings 50 and a pulley belt 51. These may together simply allow turning of the roll 21 but provide sufficient resistance to turning to keep the web 23 of dispensed flexible fibrous material 22 taut. For example the tautness may be maintained by the motorised movement of the trolley 1 (which acts to pull the web 23 from the roll 21) being partially resisted by the roll 21. It will be appreciated then that there is dispenser on the frame, which dispenses the flexible fibrous material from the roll onto the external surface of the roof.

[0091] It will be appreciated then that the flexible fibrous material is continuously dispensed as the trolley 1 moves along. In particular it is continuously dispensed and pressed onto the already dispensed fire retardant composition.

[0092] The trolley 1 is further provided with urging means in the form of spiked roller 60 which is mounted transversely on the frame 10. It will be noted that the web 23 of the flexible fibrous material runs underneath the spiked roller 60 so that the spiked roller 60 can press the web of

[0093] The spiked roller has soft flexible spikes 61 to cause a pressing action to press the fibrous material onto dispensed fire retardant composition so that the pressing action assists with impregnation of fibrous material with dispensed fire retardant composition.

[0094] It will be appreciated that pressing the flexible fibrous material into a fire retardant composition creates a flexible fibrous barrier on the external surface of the roof. This barrier provides fire resistance to the roof, for example a roofing membrane. For example this fire resistance may be important where equipment such as solar energy collection devices are provided on the roof. In this way damage to the roof caused by fire and the ignition and/or spread of fire from such equipment to the roof is reduced.

[0095] The applicator trolley 1 further comprises a screed 70 (best seen in Figure 3). As with all embodiments the screed may be of any desired form, for example a flexible screed, such as a polymeric, e.g. rubber, screed. The screed 70 is to spread dispensed fire retardant composition and may also smooth out the fire retardant composition to leave a smoother finish. It may also help with pressing the flexible fibrous material into the fire retardant composition.

[0096] The screed 70 is provided in the form of an angled blade 71 held to the frame 10 by brackets 73 which are adjustable to allow adjustment of the height and angle of the screed 70.

[0097] When the trolley 1 is in use it is supported by the wheels 17 and the roller 60.

[0098] When not in use a (castor) wheel 80 on a pivotable arm 81 which is pivotable about a bracket 83 to which is it pivotably mounted by a pin 84 may be lowered to engage the ground and hold the roller 60 off the ground. The wheel 80 is held in the raised position shown in Figure 1 by a locking pin 83. When lowered the pin 83 may be inserted again but on the opposite side of the arm 82 thus holding it in the lowered position.

[0099] Side guards 90 may be provided on the trolley 1 such as on the frame 10 and on the screed 90 to keep dispensed materials in a confined/desired lay down area.

[0100] It will be appreciated that the trolley 1 can be provided with one of more splash guards to prevent dispensed fire retardant composition splashing onto unwanted surfaces.

[0101] It will be appreciated that the applicator trolley of the invention may be used to perform the method of the invention. In particular the trolley of the invention can be utilised as mentioned above to apply to the external surface of the roof, such as to the external surface of a roofing membrane a flexible fibrous barrier, and a fire retardant composition which is flowable, for example in a liquid form, wherein the barrier comprises a flexible layer of fibrous material; so that the flexible layer of fibrous material is impregnated with the fire retardant composition. The composition can be allowed to cure and/or dry. In the context of the present invention allowing the composition to dry does not preclude the possibility of actively curing the composition for example by imparting heat etc.

[0102] As mentioned above the fire retardant composition of the invention may also be adhesive and may adhere to the external surface of the roof and thus adhere the flexible fibrous barrier to the roof.

[0103] It may be desirable to apply an adhesive promoter to promote adhesion of the fire retardant composition to the external surface of the roof. This may be pre-applied i.e. before the flexible fibrous barrier, and a fire retardant composition are applied. A trolley of the invention could be configured to do such pre-application. However it may be more convenient to paint the adhesive promoter onto the external surface of the roof.

[0104] It may be desirable to apply to adhere the flexible fibrous barrier to the external surface of the roof using an adhesive. This may be pre-applied i.e. before the flexible fibrous barrier, and a fire retardant composition are applied. A trolley of the invention could be configured to do such pre-application. However it may be more convenient to paint the adhesive onto the external surface of the roof.

[0105] Where an adhesive is used it may be desirable to apply an adhesive promoter to promote adhesion of the adhesive to the external surface of the roof. Again, this may be pre-applied i.e. before the adhesive, the flexible fibrous barrier, and the fire retardant composition are applied. A trolley of the invention could be configured to do such pre-application. However it may be more convenient to paint the adhesive promoter onto the external surface of the roof.

[0106] The adhesive promotor and/or the adhesive may be applied to the external surface of the roof and/or the flexible fibrous barrier as the flexible fibrous barrier is applied to the external surface of the roof.

[0107] It will be appreciated that the movement of the applicator trolley can be automated so that it progress under a control system which is pre-set for the desired application.

[0108] The flexible fibrous barrier may comprise a cured phosphate composition and a glass fibre scrim, wherein the glass fibre scrim. For example the glass scrim may be one which is capable of reducing the pH of demineralised water having a pH of 7 to a pH 6.3 or lower, when assessed in accordance with ISO 3071:2005; said barrier having a thickness of at least 1 mm.

[0109] The cured phosphate composition may be formed from a curable composition comprising:

(i) a phosphate selected from the group consisting of: phosphoric acid, phosphoric acid salts and combinations thereof,

(ii) a metal oxide, a metal silicate, and water,

(iii) where the weight ratio between the phosphate and the metal oxide is between about 3:1 and 1:1.

[0110] Advantageously, the combination of a glass fibre scrim capable of reducing the pH of demineralised water having a pH of 7 to a pH 6.3 or lower, when assessed in accordance with ISO 3071:2005, with the cured phosphate composition provides an effective, light-weight, fire resistant barrier. This barrier may be used to improve the fire performance of substrates to which it is attached.

[0111] The phosphate may be present in an amount of from about 10 to about 45 weight percent based on the total weight of the curable composition.

[0112] The metal oxide may be present in an amount of from about 5 to about 35 weight percent based on the total weight of the curable composition.

[0113] The metal silicate may be present in an amount of from about 1 to 15 weight percent based on the total weight of the curable composition.

[0114] The phosphate is preferably mono-potassium phosphate.

[0115] The metal oxide may be magnesium and/or calcium oxide. Preferably, the metal oxide is magnesium oxide.

[0116] The curable composition may be a two-part (2K) composition.

[0117] The phosphate and the metal oxide may be in separate parts of the two-part composition. Advantageously, this increases the shelf-life of the curable composition, and consequently, less curable composition is required to form an effective fire-resistant barrier.

[0118] The curable composition may further comprise a silica containing compound.

[0119] The curable composition may further comprise an adhesion promoter, for example, the curable composition may comprise an alcohol such as ethanol, propanol, butanol or isomers thereof. The adhesion promoter may be isopropanol, ethanol, ether, sodium silicate, limonene, an acrylic-styrene based co-polymer or combinations thereof. Preferably, the adhesion promoter is an acrylic-styrene based co-polymer. Suitably, the adhesion promoter comprises an aqueous emulsion comprising an acrylic-styrene based copolymer.

[0120] Additionally or alternatively, a surface to which the barrier will be attached may be pre-treated with an adhesion promoter, prior to application of the barrier to the substrate. The surface may be that of a roofing membrane.

[0121] Pre-treatment of the structural element with the adhesion promoter may be achieved by application of the adhesion promoter to a first surface of the structural element by pouring, rolling, or spraying the adhesion promoter on said first surface. Preferably, the adhesion promoter is sprayed on the first surface of the structural element.

[0122] Advantageously, the use of an adhesion promoter increases the strength of the attachment of the curable composition to a surface to which it is applied.

[0123] When present in the curable composition, the adhesion promoter may be present in an amount of from about 0.01 to about 5 wt% based on the total weight of the curable composition. Suitably, the adhesion promoter is present in an amount of from about 0.1 to about 2 wt%, such as from about 0.5 to about 1.5 wt% based on the total weight of the curable composition.

[0124] The adhesion promoter may be applied by spraying a first surface of the structural element with said adhesion promoter. The adhesion promoter may be applied at a surface area coverage of from about 75 g/m² to about 180 g/m², suitably, at a surface area coverage of from about 100 g/m² to 150 g/m².

[0125] The glass fibre scrim may have a tensile strength as determined in accordance with DIN EN ISO 13934-1 of at least about 500 N, suitably from about 500 N to about 1000 N in the longitudinal direction. This imparts significant strength to the barrier and indeed to a construction article comprising the barrier. When the glass fibre scrim has a tensile strength of less than 500 N, a barrier formed therewith will tend to bend more easily. Preferably, the glass fibre scrim is a glass fibre woven scrim.

[0126] The glass fibre scrim may have a mesh size in the range of from 0.5 mm x 0.5 mm to 9 mm x 9 mm, preferably the mesh size is of from 1 mm x 1 mm to 5 mm x 5 mm. If the mesh size is less than 0.5 mm x 0.5 mm, penetration of the curable phosphate composition through the glass fibre scrim, and impregnation of the curable phosphate composition in the glass fibre scrim is reduced. The barrier has optimal fire retardancy when the mesh size is 0.5 mm x 0.5 mm to 9 mm x 9 mm. If the glass fibre scrim mesh size is too large i.e. greater than about 9 mm x 9 mm, cracks can occur in the barrier during a fire, and an underlying structural element to which the barrier is attached will be exposed to the fire.

[0127] The glass fibre scrim may for example have a weight of from about 40 to about 400 g/m². Suitably, the glass fibre scrim has a weight of from about 50 g/m² to about 250 g/m², or from about 70 g/m² to about 220 g/m². Preferably the glass fibre scrim has a weight of from about 150 g/m² to 220 g/m². If the scrim is too heavy, for example a scrim having a weight of greater than 220 g/m², impregnating the scrim with the curable composition is more challenging. The barrier has optimal strength when the glass fibre scrim has a weight in the range of from about 150 g/m² to 220 g/m², such as from 150 g/m2 to 200 g/m2.

[0128] Advantageously, the glass fibre scrim employed in the present invention is sufficiently hydrophilic to be impregnated by a curable phosphate composition.

[0129] The flexible fibrous barrier may have a thickness of from about 1 mm to about 10 mm, preferably about 1.5 mm to about 5 mm, such as from about 2 mm to about 4 mm.

[0130] Suitably the flexible fibrous barrier may have a thickness of about 1 mm and a weight of about 1.3 to about 1.5 kg/m².

[0131] The words "comprises/comprising" and the words "having/including" when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0132] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

Claims

1. A method of treating an external surface of a roof, such as the external surface of a roofing membrane, to enhance fire performance, the method comprising the steps of:
applying to the external surface of the roof, such as to the external surface of a roofing membrane a flexible fibrous barrier, and a fire retardant composition which is flowable, for example in a liquid form, wherein the barrier comprises a flexible layer of fibrous material; so that the flexible layer of fibrous material is impregnated with the fire retardant composition; and allowing the composition to cure and/or dry.

2. A method according to Claim 1 comprising the step of adhering the flexible fibrous barrier to the external surface of the roof.

3. A method according to any preceding claim wherein the fire retardant composition adheres to the external surface of the roof, optionally further comprising the step of applying adhesive promoter to promote adhesion of the fire retardant composition to the external surface of the roof.

4. A method according to any preceding claim comprising the step of applying adhesive to adhere the flexible fibrous barrier to the external surface of the roof.

5. A method according to any of Claims 3 or 4 wherein the adhesive promotor and/or the adhesive is applied to the external surface of the roof and/or the flexible fibrous barrier as the flexible fibrous barrier is applied to the external surface of the roof.

6. A method according to any preceding claim wherein the fire retardant composition is applied to the flexible layer of fibrous material as the flexible layer of fibrous material is being applied to the external surface of the roof.

7. A method according to any preceding claim comprising using a screed, for example a flexible screed such as a polymeric, e.g. rubber, screed to spread the fire retardant composition.

8. A method according to any preceding claim comprising using a roller to tension the flexible fibrous barrier so that it can be held taut as it is applied to the external surface of a roof, such as the external surface of a roofing membrane.

9. A method according to any preceding claim wherein the external surface of the roof is an external surface of a roofing membrane which is a PVC membrane, an EPDM (ethylene propylene diene monomer) membrane, or a bituminous membrane.

10. A method according to any preceding claim wherein the fire retardant composition is a two-part composition and the method comprising mixing the two parts of the composition.

11. An applicator trolley for applying a flexible barrier to an external surface of a roof, such as the external surface of a roofing membrane, to enhance fire performance, the applicator comprising:

(a) a wheeled frame,

(b) a holder on the frame, the holder for holding a roll of flexible fibrous material,

(c) a dispenser on the frame, the dispenser for dispensing the flexible fibrous material from the roll onto the external surface of the roof.

12. An applicator trolley according to Claim 11 further comprising a dispensing head for dispensing a fire retardant composition, optionally wherein the dispensing head is a spray head.

13. An applicator trolley according to any of Claims 11 to 12 wherein the trolley comprises a mixer for mixing two parts of a two-part fire retardant composition, optionally wherein the mixer for mixing two parts of a two-part fire retardant composition is attached to a dispensing head for dispensing a fire retardant composition.

14. An applicator trolley according to any of Claims 11 to 13 wherein the applicator trolley is adapted to continuously apply a fire retardant composition and then immediately thereafter apply the fibrous material, for example a flexible layer of fibrous material, to the fire retardant composition, and optionally wherein the trolley further comprises urging means to cause a pressing action to press the fibrous material onto dispensed fire retardant composition so that the pressing action assists with impregnation of fibrous material with dispensed fire retardant composition.

15. An applicator trolley according to Claim 14 wherein the urging means comprises a roller such as a spiked roller, for example a spiked roller where the spikes are resiliently deformable.

16. An applicator trolley according to any of Claims 11 to 15 wherein the applicator trolley further comprises a screed, for example a flexible screed, such as a polymeric, e.g. rubber, screed to spread a fire retardant composition, and/or wherein the applicator trolley is adapted to hold and dispense a web of the flexible fibrous material.

Drawing