WO2011079275A2

WO2011079275A2 - Fire protective barrier and method of applying

Info

Publication number: WO2011079275A2
Application number: PCT/US2010/062026
Authority: WO
Inventors: Dennis C. Miller
Original assignee: American Sprayed Fibers
Priority date: 2009-12-23
Filing date: 2010-12-23
Publication date: 2011-06-30
Also published as: WO2011079275A3; WO2011079275A9

Abstract

An inventive method of applying an ignition barrier to a mass of foam plastic insulation. The method includes applying at least one layer of protective material to the foam. The protective material includes a silicate material and a liquid and has a wet thickness of at least about 12 mils. The protective material provides an ignition barrier for at least 4 minutes and 18 seconds. The silicate material can be silica sand and a second material such as soda ash or potassium oxide. The silica sand and second material are present in a weight ratio of between about 1:1 and about 20:1 with some embodiments having a weight ratio of about 4: 1 or about 3.22: 1. The protective material may also be applied in a sufficient thickness, e.g., between about 26 to 80 mils and advantageously between about 50 to 52 mils, to form a thermal barrier for the foam plastic insulation.

Description

FIRE PROTECTIVE BARRIER AND METHOD OF APPLYING

This application claims priority from U.S. Provisional Patent Application Serial No. 61/289,639 filed on December 23, 2009 and entitled FIRE PROTECTIVE BARRIER AND METHOD OF APPLYING, the entire disclosure of which, including all Appendices, is hereby incorporated herein by reference.

BACKGROUND

[0001] The present invention relates to a coating or layer of protective material, and more particularly, to a method of applying the coating or layer of protective material as a fire barrier.

[0002] Fire protection of a building or structure, for example, can include three main sources of protection. First, active fire protection comprises manual or automatic fire detection and fire suppression. On the other hand, passive fire protection includes compartmentalizing the building or structure through the use of fire-resistance rated walls and floors. Lastly, fire prevention includes minimizing ignition sources and educating occupants of the building or structure concerning the operation and maintenance of fire-related systems.

[0003] Passive fire protection ("PFP") is a means for containing fires or reducing the speed at which a fire spreads. This form of protection, also referred to as fireproofing, includes the act of making materials of a structure more resistant to fire or the act of applying fire resistant materials within the structure. PFP systems must comply with various standards in order to provide the effectiveness expected by building codes. The goal for PFP systems is to demonstrate through fire testing the ability to maintain an item such as a wall, floor, etc. at or below 140 ^°C (-284 ^°F) or approximately 550 °C (-1022 ^°F), which is considered the critical temperature for structural steel. This is based, in most countries, on basic test standards for walls and floors such as ASTM El 19 and those set forth by the National Fire Protection Association ("NFPA") headquartered in Quincy, MA such as NFPA 286.

[0004] To accomplish the goals for PFP systems, many different types of materials are used in the design and construction of such systems. For example, common endothermic building materials include concrete and gypsum wallboard. PFP measures can further include intumescents and ablative materials. [0005] Thermal insulation and fireproofing materials can reduce the flow of heat through the thickness of the material. These materials can be fiber-based or foam structures prepared from thermally-stable materials. According to http://materials.globalspec.com, there are several basic material types of thermal insulation and fireproofing materials. These include fiberglass, glass wood, polymeric materials, cellulose fibers, and ceramics or refractories. There are also five main forms for thermal insulation and fireproofing materials including bulk chopped fibers, textiles or fibrous mats, foam, board and block insulation, and films or foils. Foam insulation, for example, can be made from low-density elastomers, plastics, and other materials with various porosities. Thermal insulation and fireproofing materials differ in terms of specifications and features. Use temperature and thermal conductivity, for example, are two important parameters to consider. Use temperature is defined as the temperature range through which a material can be exposed without degradation of its structural or other required end-use properties. On the other hand, thermal conductivity refers to the linear heat transfer per unit area through a material for a given applied temperature gradient.

[0006] With respect to foam insulation, there are two main types: open-cell and closed cell. Open cell foam is porous and allows water vapor and liquid water to penetrate the insulation. Closed cell foam is non-porous and does not allow moisture to penetrate therethrough.

Closed cell foam is an effective vapor barrier and can provide superior insulation. The advantages of foam insulation include blocking airflow, serving as a vapor barrier, and filling wall cavities. Examples of sprayed foam insulation include Icynene® spray formula, polyicynene, cementitious foam, phenolic, and others,

[0007] Fireproofing often becomes a challenge when dealing with small areas such as attics or crawlspaces. For this reason, building codes have established standards for fireproofing such areas in residential and commercial structures. International Building Code 2603.4.1.6, for example, states that "within an attic or crawl space where entry is made only for service of utilities, foam plastic insulation shall be protected against ignition by 1.5" thick mineral fiber insulation; 0.25" thick wood structural panel, particleboard or hardboard, gypsum wallboard, corrosion-resistant steel having a base metal thickness of 0.016" or other approved material installed in such a manner that the foam plastic insulation is not exposed." In other words, a barrier is required for separating the foam from the occupied space (e.g., the attic or crawlspace).

[0008] Current building codes also typically require what is referred to as a "thermal barrier" in commercial buildings and structures. A thermal barrier is typically required for foam plastic insulation in commercial buildings, however, such a thermal barrier is not typically required for residential structures. If a fire breaks out in the structure, the thermal barrier protects the structural integrity of the building or structure for at least fifteen minutes to allow a person or group of people within the building or structure to exit before the fire damages the structural integrity. In other words, the thermal barrier is a safety measure that provides a period of time for occupants of a structure to exit immediately after a fire has started and before the building collapses.

[0009] Recently, a new building standard has been established by the International Building Code (IBC) and will go into effect shortly. The new building standard requires an ignition barrier to be applied to foam plastic insulation which is capable of preventing the foam plastic insulation from igniting for at least four minutes and eighteen seconds. It has been determined that foam plastic insulation typically ignites at about 250 above the ambient temperature. Thus, if an attic is insulated with a foam plastic insulation and the temperature therein is 110 °F, the ignition barrier must prevent the foam from exceeding 360 ^°F for at least four minutes and eighteen seconds.

[0010] There are several commercial types of ignition barriers in use today such as glass fiber insulation batts, ¼" plywood, and 3/8" gypsum board. Even if such existing materials can be employed in a manner to satisfy the new ignition barrier requirements for foam plastic insulation, these ignition barriers have several disadvantages. For instance, some materials are very expensive (e.g., $85 - $100 per gallon) and can be difficult to apply to the foam plastic insulation. Some materials are latex-based and require significant amounts of time to be applied to the foam. Other materials can only cover a limited area, e.g., 200 square feet from a 5 gallon container.

[0011] Thus, a need exists for a material that can satisfy the new ignition barrier code requirement and overcome the disadvantages of the prior art, i.e., reduce application time, enhance the ease of application, reduce cost, and be economically friendly and safe to apply. SUMMARY OF THE INVENTION

[0012] The invention comprises, in one form thereof, a method of applying an ignition barrier to a structure which includes a mass of foam plastic insulation defining a surface. The method includes applying at least one layer of protective material to the surface, the protective material comprising a silicate material and a liquid and wherein the at least one layer has a wet thickness of at least about 12 mils. (One mil is equal to 0.001 inch.) The protective material is allowed to dry for a period of time wherein, when dry, the protective material provides an ignition barrier for the foam plastic insulation for at least 4 minutes and 18 seconds when tested in accordance with NFPA 286.

[0013] Advantageously, the layer of protective material has a total wet thickness of between about 12 mils and about 26 mils. The silicate material in the protective material may be silica sand and a second material wherein the second material is either soda ash or potassium oxide. The silica sand and second material may be present in the protective material in a weight ratio of between about 1 : 1 and about 20:1. Advantageously, the weight ratio of the silica sand and the second material is about 4:1 and, even more advantageously, the weight ratio is about 3.22:1. In some embodiments, the protective material is about 37% solids and about 63% liquid by volume when applied.

[0014] The protective material can be applied in a single layer having a wet thickness of about 12 mils to provide an ignition barrier for plastic foam insulation. The ability to apply such a thin coating of material in a single layer to provide an ignition barrier provides significant labor and material savings.

[0015] In some embodiments, a dye is added to the protective material prior to applying the protective material to the surface. By adding a dye, the areas where the protective material have already been applied can be visually distinguished with ease and the application of the protective material is facilitated. The protective material, in some embodiments, has the same properties as a liquid adhesive and is readily applied directly to the surface of plastic foam insulation by spraying,

[0016] The protective material can be applied in a single coat or layer. Alternatively, it can be applied in multiple layers. For example, the step of applying at least one layer of protective material can involve applying a tack coat layer of the protective material on the surface; allowing the tack coat layer to dry for a period of time; and then applying a second layer of the protective material on the tack coat layer wherein the combined wet thickness of the tack coat layer and the second layer is at least about 26 mils. In still another alternative embodiment of this invention, the step of applying at least one layer of protective material may also include applying a third layer of the protective material on the second layer, wherein, when the third layer dries, the tack coat layer, the second layer and the third layer form a thermal barrier that prevents the temperature of the foam plastic insulation from exceeding the ambient temperature plus 250 °F for at least 15 minutes when tested in accordance with NFPA 286. The combined wet thickness of the tack coat layer, the second layer and the third layer is advantageously between about 26 mils and about 80 mils. More advantageously, the combined wet thickness of the tack coat layer, the second layer and the third layer is at least about 50 mils.

[0017] The invention comprises, in another form thereof, an ignition barrier adapted for use with foam plastic insulation defining a surface. The ignition barrier ignition includes a layer of protective material disposed on the surface wherein the protective material comprises silica sand and a second material in a weight ratio of between about 1 : 1 and about 1 :20 and wherein the protective material provides an ignition barrier for the foam plastic insulation for at least about 4 minutes and 18 seconds when tested in accordance with NFPA 286.

The second material can be potassium oxide. Alternatively, the second material may be soda ash. In some embodiments, the layer of protective material has an applied wet thickness of between about 12 mils and about 80 mils. Advantageously, the layer of protective material has an applied wet thickness of between about 12 mils and about 26 mils wherein the protective material is formed of silica sand and soda ash at a weight ratio of about 3.22:1. By using such a protective material with a wet thickness of at least about 50 mils it can form a thermal barrier that prevents the temperature of the foam plastic insulation from exceeding the ambient temperature plus 250 °F for at least 15 minutes when tested in accordance with NFPA 286. Advantageously, such protective material configurations can be combined with a mass of foam plastic insulation for installation in a structure.

[0018] These embodiments provide several advantages. For example, the protective material can be economically applied by spraying. It can also be rolled or brushed onto plastic foam insulation. It is also a relatively inexpensive material. Moreover, a very thin application of the material can be used to provide an ignition and a relatively thin application can provide a thermal barrier thereby relatively small quantities of the protective material to provide a barrier for relatively large surface areas. This not only helps to reduce material and labor costs but also reduces transportation and storage costs.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above-mentioned aspects of the present invention and the manner of obtaining them will become more apparent and the invention itself will be better understood by reference to the following description of the embodiments of the invention, taken in conjunction with the accompanying drawings, wherein:

[0020] Fig. 1 is a flow chart of an exemplary embodiment for applying an ignition barrier and/or thermal barrier to foam plastic insulation.

[0021] Figs. 2-9 provide information related to a burn test of a control structure and a sample having a 12 mil wet thickness layer of protective material applied to a mass of plastic foam insulation.

[0022] Figs. 10-13 provide information related to a burn test of a sample having a 50 mil wet thickness layer of protective material applied to a mass of plastic foam insulation.

DETAILED DESCRIPTION

[0023] The embodiments of the present invention described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art can appreciate and understand the principles and practices of the present invention.

[0024] In an exemplary embodiment of the present invention, a protective material is provided that is water-based and can be used as an ignition barrier for fireproofing a space such as a bedroom, kitchen, closet, bathroom, attic, crawlspace, etc. The material can also be used as a thermal barrier, which will be described in further detail below. The material can be applied over various types of insulation including foam plastic insulation. While the material can be applied in any number of ways, such as rolling and brushing, it is

advantageously sprayed onto the foam. An airless sprayer, for example, can apply one or more coats of the material to the foam insulation. [0025] Since foam products are highly combustive and generate smoke, which can be lethal if inhaled over a period of time, the IBC has issued a new code requiring an "ignition barrier" to be applied to the foam. In the event a fire breaks out in an attic, for example, and foam insulation is used in the attic, the new code requires the ignition barrier to prevent the foam from igniting for at least four minutes and eighteen seconds. This new code requirement applies to both commercial and residential buildings and structures.

[0026] In an exemplary embodiment, the protective material is a mixture of both solids and liquid. For example, the solids can include any silicate material such as sodium silicate or potassium silicate (which will be described below). In one embodiment, the mixture can comprise between 10-90% solids and 90-10% liquids. The liquid can, for example, be water. Other liquids can also be used alternatively or mixed with water. In an advantageous embodiment, the mixture can comprise about 37% solids and 63% liquid by volume. The mixture is capable of providing an ignition barrier for four minutes and eighteen seconds as required under applicable building codes. In addition, if the mixture is applied in a sufficient thickness, it is also able to provide a thermal barrier for fifteen minutes under applicable building codes.

[0027] In a non-limiting embodiment, the material includes a mixture of a silicate and flour. The silicate can include a synthetic silicate, a refined silicate, a mine silicate, and/or a silicate gel. In another embodiment, the material can comprise a composition of silica sand and soda ash. For example, in one aspect of this embodiment, the composition can have a weight ratio of silica sand to soda ash of between about 1 :1 to 20:1. In a different aspect, the composition can have a weight ratio of about 4: 1. More particularly, in another aspect, the weight composition can be about 3.22:1. Liquid sodium silicate, for example, is alkaline and can have a pH between 11-12 and is available in different ratios of silica sand to soda ash.

[0028] In another non-limiting embodiment, the ignition and thermal barriers can comprise a form of potassium silicate. Potassium silicate is alkaline and can be provided in a range of weight ratios of silica sand to potassium oxide. In one aspect, for example, the ignition barrier material can include a composition having a weight ratio of silica sand to potassium oxide of between about 1 : 1 to 20: 1. In one exemplary aspect, the composition can have a weight ratio of about 4:1. In another non-limiting aspect, the composition can have a weight ratio of about 3.22:1. [0029] Advantages of using silicate materials over prior art ignition and thermal barriers include lower cost, greater coverage per square unit, and reduced application cost.

Additionally, the equipment time required used to apply the material is less and less material has to be transported to a job site. The material is easy to prepare and clean up, and the shelf life of this material is significant. Other advantages of this material include non-toxic, non- corrosive to steel, copper, or aluminum, it is inorganic, and non-combustible. It has been found that the material does not support fungus or mold, it does not contain an unpleasant odor, and it does not absorb moisture. Most importantly, however, these materials are able to act as an ignition barrier and can also be employed as both an ignition barrier and a thermal barrier.

[0030] Additional advantages of this material for use as an ignition barrier and thermal barrier over foam plastic insulation are found from test results in which the material was used for being certified as satisfying the new IBC code requirement.

SAMPLE TEST SETUP AND RESULTS

[0031] The test specimen consisted of four walls with 2x6 studs, 16 inches o.c. and 2x12 joists, 16 inches o.c. with ½ inch CDX plywood. A door is provided at a fourth end of the room and is the only opening therein. The doorway consists of a 30 ± 0.25 by 80 ± 0.25 inch opening in the center of one of the 8 feet by 8 feet walls. The final interior dimensions were 8 feet high, 8 feet wide and 12 feet deep. The stud cavities were filled 5 ½ inches of LD-C- 50 open cell spray foam from Icynene® in the walls and 14 inches of LD-C-50 foam in the ceiling. Approximately 21 wet mils of material suitable for an ignition barrier was sprayed on the inside of the room covering the foam on the walls only.

[0032] The testing standard described a method for evaluating spray applied foam plastic insulated assemblies for flashover conditions and contribution of room fire growth during specified fire exposure conditions. The test indicated the time to flashover of the walls and ceiling. It did not measure the fire growth in, or the contribution of, the room contents. Time to flashover was defined as the amount of time until flames from the fire exited through the doorway. Alternatively, if smoke obscured observations, the time when the radiant flux onto the floor reaches 20 kW/m2, the temperature of the upper air reaches 600 °C, or spontaneous ignition of two newspaper "targets" placed on the floor may also provide indication of flashover condition. A comparison, or baseline assembly, was also constructed for comparative purposes. The baseline assembly is covered by ¼ inch thick A-C or B-C plywood on the interior walls.

[0033] As for test equipment and instrumentation, the ignition source for the test was a gas burner with a nominal 12-by-12 inch porous top surface of a refractory material. The burner used in this test was filled with a minimum 4-inch layer of Ottawa sand. The top surface of the burner through which gas is applied was positioned 12 inches above the floor, and the burner enclosure was located such that the edge of the diffusion surface was located in a back corner of the room opposite the door.

[0034] The gas supplied to the burner was CP. grade propane. The burner was capable of producing a gross heat output of 40 ± 1 kW for five minutes followed by a 160 ± 5 kW for ten minutes. The flow rate was metered throughout the test. The design of the burner controls was such that when one quarter-turn ball valve was opened, the flow of gas to the burner produced 40 kW and when a second quarter-turn valve was opened the combined flow produces 160 kW.

[0035] The test procedure followed is identical to that required for NFPA 286. Before testing, the ambient temperature of the room is tested and then the burner is ignited at a fuel flow rate that is known to produce 40 kW of heat output. This level of heat was maintained for five minutes after which the fuel flow was increased to 160 kW for a ten minute period. During the burn period, all temperature, heat release and heat flux data was recorded every six seconds. At the conclusion of the fifteen minute period, the burner was shut off and all instrument readings were stopped. All damage was documented after the test concluded, and photographs, drawings, and other means were used for describing the test.

[0036] The following results and observations were made:

Base Burn - Ambient temperature was 64 °F

2:38 Flame tips at 8 foot in corner above burner

2:50 Discoloration on ceiling

3:02 Increase in smoke

3:31 Ignition of foam on ceiling

3:40 Heavy smoke

4:16 Flames out door

Product Test (with Ignition Barrier) - Ambient temperature was 68 °F

TIME

(min:sec) OBSERVATION

0:00 Ignition of Burner. Heat output set to 40kW (550 ^°F)

0:39 Light smoke

0:50 Discoloration of paint

1 :02 Ignition of side wall

1 :26 Increase in smoke

1 :38 Ignition back wall

1 :50 Flames 5ft vertically above burner increase in smoke

2:28 Flame tips 7ft vertically in corner

3:10 Flames recede to 3ft vertically above burner

4: 17 No flashover

5:00 Increase to 160 kW (1650 ^°F)

5:10 Flames at 7ft horizontally on ceiling

5:20 Heavy smoke

5:36 Flames out door

[0037] The test, commonly referred to as a "corner room test", requires that the material applied to the foam insulation must keep the flame from the ignition source from spreading vertically along the wall, igniting the ceiling and burning across the ceiling and exit through the doorway for four minutes and eighteen seconds. In the table above for the product test, flames did not exit through the doorway until after five minutes and thirty-six seconds. What was unexpected about the test, however, was that at the three minute and ten second mark the flame actually receded from seven feet above the burner to three feet above the burner. In other words, the material used as the ignition barrier actually retarded the flame and caused it to recede.

TEST USING 12 MIL THICKNESS

[0038] An additional test was conducted for Icynene on LD-C-50 open cell spray foam to evaluate heat release and flame spread properties when subjected to specific ignition conditions. Testing was conducted in accordance with NFPA 286 and (AC 377) Appendix A.

[0039] Batching was done from randomly selected drums from the manufacturing facility of Icynene Inc. located at 6747 Campobello Road, Mississauga, Ontario Canada. The selected material was Icynene's documented formulation and utilized normal manufacturing procedures. The sampled resin and ISO components were applied in accordance with the manufacturer's installation instructions.

[0040] The specimen consisted of three walls with 2x6 studs, 16 inches o.c. and 2x12 joists, 16 inches o.c. with 1/2 inch CDX plywood on the exterior of room. The final interior dimensions were 8 feet high, 8 feet wide and 12 feet deep. The stud cavities were filled with 5.5 inches of LD-C-50 and 14 inches of LD-C-50 in the ceiling and then 12 wet mils of the protective material was sprayed on the inside of the room covering the foam on the walls only. The protective material was a mixture of silica sand and soda ash i.e., Si0₂/Na₂0, at a weight ratio of 3:22: 1 and mixed with water wherein the protective material was 37% solids and 63% liquid by volume.

[0041] An identical control assembly was constructed as above and covered with 0.25 inch, B-C plywood on the interior walls.

[0042] The test applied a standard for evaluating spray applied foam plastic insulated assemblies for flashover conditions and contribution of room fire growth during specified fire exposure conditions. This method is not intended to evaluate the fire endurance of assemblies, nor is it able to evaluate the effect of fires originating within the wall assembly.

[0043] The test indicates the time to flashover of the walls and ceiling. It does not measure the fire growth in, or the contribution of, the room contents. Time to flashover is defined herein as the time to flames exiting the doorway. When smoke obscures observations, the time when the radiant flux onto the floor reaches 20 kW/m , the temperature of the upper air reaches 600°C, or spontaneous ignition of two newspaper 'targets' placed on the floor provides indication of flashover condition.

[0044] A comparison, or baseline assembly, is also constructed for comparative purposes. This assembly is identical to the subject assembly, but is covered by 0.25 inch thick A-C or B-C plywood on the interior walls instead of the protective material coating being evaluated.

[0045] The ignition source for the test is a gas burner with a nominal 12- by 12-inch porous top surface of a refractory material. The burner used is filled with a minimum 4-inch layer of Ottawa sand.

[0046] The top surface of the burner through which the gas is applied is positioned 12 inches above the floor, and the burner enclosure is located such that the edge of the diffusion surface is located one inch from product in either back corner of the room opposite from the door.

[0047] The gas supply to the burner is CP. grade propane (99 percent purity). The burner is capable of producing a gross heat output of 40±1 KW for five minutes followed by a 160±5 kW for ten minutes. The flow rate is metered throughout the test. The design of the burner controls is such that when one quarter-turn ball valve is opened, the flow of gas to the burner produces 40 kW and when a second quarter-turn valve is opened the combined flow produces 160 kW.

[0048] The interior dimensions of the floor of the fire room, when the specimens are in place, measures 8 feet, by 12 feet. The finished ceiling is 8 feet ± 0.5 inches above the floor. The four walls are at right angles defining the compartment. The compartment contains a 30 ± 0.25 inch by 80 ± 0.25 inch doorway in the center of one of the 8 foot by 8 foot walls. No other openings are present to allow ventilation.

[0049] The test procedure used is identical to that required for NFPA 286 and is described below.

[0050] A calibration test is run within 30 days of testing any material as specified in the standard. All instrumentation is zeroed, spanned and calibrated prior to testing. The specimen is installed and the diffusion burner is placed. The collection hood exhaust duct blower is turned on and an initial flow is established. The gas sampling pump is turned on and the flow rate is adjusted. When all instruments are reading steady state conditions, the computer data acquisition system and video equipment is started. Ambient data is taken then the burner is ignited at a fuel flow rate that is known to produce 40 kW of heat output. This level is maintained for five minutes at which time the fuel flow is increased to the 160 kW level for a 10-minute period. During the burn period, all temperature, heat release and heat flux data is being recorded every 6 seconds. At the end of the fifteen minute burn period, the burner is shut off and all instrument readings are stopped. It is not expected that control assemblies will last the full 15 minutes.

[0051] The time to flashover of the subject assembly is compared to the baseline, A satisfactory or "passing" result is judged by no flashover of the subject assembly at the time that the baseline assembly reached flashover conditions.

[0052] The results and observations for the control test and the product (protective material having 12 mil wet thickness) test are presented below.

Base Burn (Plywood Faced Control Assembly)

[0053] When the test was conducted, the ambient temperature was 80°F with a relative humidity of 33%. The data acquisition system was started and the burner was ignited. Events during the test are described below:

Product Test (12 mil wet thickness layer of protective material)

[0054] When the test was conducted, the ambient temperature was 63 °F with a relative humidity of 48%. The data acquisition system was started and the burner was ignited. Events during the test are described below:

Test Results for these same two burns are presented below:

Base Burn

Flames out the door 4:29

Average of the above 4:27

[0055] Figs. 2-5 include four graphs illustrating data for the base burn. These graphs include thermocouple data (Fig. 2), smoke release data (Fig. 3), heat release data (Fig. 4) and radiant heat data (Fig. 5).

Product Data

[0056] Figs. 6-9 include four graphs illustrating data for the test burn of the sample including a 12 mil wet thickness layer of protective material. These graphs include thermocouple data (Fig. 6), smoke release data (Fig. 7), heat release data (Fig. 8) and radiant heat data (Fig. 9).

[0057] In reference to the NFPA 286 IBC-ES AC 377 section A.l.2.2 the sample surpassed the time to flash over of the control assembly which was 4:29 min/sec and therefore met the requirements set forth in AC 377. As a person having ordinary skill in the art will also recognize, the 12 mil layer of protective material in this example also provided an ignition barrier for a length of time in excess of four minutes and eighteen seconds when tested in accordance with NFPA 286.

TEST WITH 50 MIL THICKNESS

[0058] Another test was conducted using Icynene on LD-C-50 open cell 0.5 pound spray foam with 50 wet mils 8 gal/352 ft of the same protective material used in the 12 mil test described above to evaluate heat release and flame spread properties when subjected to specific ignition conditions. Testing was conducted in accordance with NFPA 286. [0059] Batching was done with randomly selected drums from the manufacturing facility of Icynene Inc. located at 6747 Campobello Road, Mississauga, Ontario Canada. The selected material matched Icynene's documented formulation and employed normal manufacturing procedures. The resin and ISO components were applied in accordance with the manufacturer's installation instructions.

[0060] The test specimen consisted of three walls with 2x6 studs, 16 inches o.c. and 2x12 joists, 16 inches o.c. with 0.5 inch CDX plywood. The final interior dimensions were 8 feet high, 8 feet wide and 12 feet deep.

[0061] The stud cavities were filled 6 inches of LD-C-50 in the walls and 14 inches of LD-C-50 in the ceiling. The room was heated to nominal 60 degrees. Then 50 wet Mils 8 gal/352 ft² of the protective material was sprayed on the walls and ceiling. There was a 10 mil tack coat then the remaining 40 mils followed.

[0062] The test applied a standard for evaluating spray applied foam plastic insulated assemblies for flashover conditions and contribution of room fire growth during specified fire exposure conditions. This method is not intended to evaluate the fire endurance of assemblies, nor is it able to evaluate the effect of fires originating within the wall assembly. The method is not intended for the evaluation of floor finishes.

[0063] This method is to be used to evaluate the flammability characteristics of finish wall and ceiling coverings when such materials constitute the exposed interior surfaces of buildings. This test method does not apply to fabric covered less than ceiling height, freestanding, prefabricated panel furniture systems or demountable, relocatable, full-height partitions used in open building interiors. Freestanding panel furniture systems include all freestanding panels that provide visual and/or acoustical separation and are intended to be used to divide space and may support components to form complete work stations.

[0064] This fire test measures certain fire performance characteristics of finish wall and ceiling covering materials in an enclosure under specified fire exposure conditions. It determines the extent to which the finish covering materials may contribute to fire growth in a room and the potential for fire spread beyond the room under the particular conditions simulated. The test indicates the maximum extent of fire growth in a room, the rate of heat release, and if they occur, the time to flashover and the time to flame extension beyond the doorway following flashover. It does not measure the fire growth in, or the contribution of, the room contents. Time to flashover is defined herein as either the time when the radiant flux onto the floor reaches 20 kW/m or the temperature of the upper air reaches 600°C. A pair of crumpled single sheets of newspaper is placed on the floor 2 feet out from the center of the rear wall and front walls to determine flashover. The spontaneous ignition of this newspaper provides a visual indication of flashover.

[0065] The potential for spread of fire to other objects in the room, remote from the ignition source, is evaluated by measurements of:

1. The total heat flux incident on the center of the floor.

2. A characteristic upper-level gas temperature in the room.

3. Instantaneous net peak rate of heat release.

The potential for the spread of fire to objects outside the room of origin is evaluated by the measurement of the total heat release of the fire.

[0066] The ignition source for the test is a gas burner with a nominal 12- by 12-inch porous top surface of a refractory material. The burner is filled with a minimum 4-ineh layer of Ottawa sand.

[0067] The top surface of the burner through which the gas is applied is positioned 12 inches above the floor, and the burner enclosure is located such that the edge of the diffusion surface is located 1 inch from both walls in the left corner of the room opposite from the door.

[0068] The gas supply to the burner is CP. grade propane (99 percent purity). The burner is capable of producing a gross heat output of 40±1 KW for five minutes followed by a 160±5 kW for ten minutes. The flow rate is metered throughout the test. The design of the burner controls is such that when one quarter-turn ball valve is opened, the flow of gas to the burner produces 40 kW and when a second quarter-turn valve is opened the combined flow produces 160 kW.

[0069] The interior dimensions of the floor of the fire room, when the specimens are in place, measures 8 feet, by 12 feet. The finished ceiling is 8 feet ± 0.5 inches above the floor. The four walls are at right angles defining the compartment. The compartment contains a 30 ± 0.25 inch by 80 ± 0.25 inch doorway in the center of one of the 8 foot by 8 foot walls. No other openings are present to allow ventilation.

[0070] A calibration test is run within 30 days of testing any material as specified in the standard. All instrumentation is zeroed, spanned and calibrated prior to testing. The specimen is installed and the diffusion burner is placed. The collection hood exhaust duct blower is turned on and an initial flow is established. The gas sampling pump is turned on and the flow rate is adjusted. When all instruments are reading steady state conditions, the computer data acquisition system and video equipment is started. Ambient data is taken then the burner is ignited at a fuel flow rate that is known to produce 40 kW of heat output. This level is maintained for five minutes at which time the fuel flow is increased to the 160 kW level for a 10-minute period. During the burn period, all temperature, heat release and heat flux data is being recorded every 6 seconds. At the end of the fifteen minute burn period, the burner is shut off and all instrument readings are stopped. Post test observations are made and this concludes the test.

[0071] The results and observations for the test utilizing a protective material having a 50 mil wet thickness are presented below.

[0072] When the test was conducted, the ambient temperature was 68°F with a relative humidity of 71 %. The data acquisition system was started and the burner was ignited. Events during the test are described below:

[0073] Figs. 10-13 include four graphs illustrating data for the test burn. These graphs include thermocouple data (Fig. 10), smoke release data (Fig. 11), heat release data (Fig. 12) and radiant heat data (Fig. 13). [0074] After the test, the specimen showed heavy char damage in the corner from 1 ft to 8 ft vertically above burner. The test specimen met the criteria of 2006 International Building Code ("IBC") 803.2.1. In other words, the 50 mil layer of protective material in this example provided a thermal barrier for at least 15 minutes when tested in accordance with NFPA 286.

Method of Application

[0075] The materials described above for use as an ignition barrier and/or thermal barrier can be applied in accordance with the flowchart of Fig. 1. For an ignition barrier, the thickness of the material (e.g., mixture of sodium silicate and water) can be between about 10 wet mils and about 52 wet mils and can be applied in a single layer or coat or can be applied in multiple coatings to achieve the desired thickness. In one embodiment, an ignition barrier can be provided by applying a single coat of protective material having a wet thickness of approximately 12 mils. In another embodiment, an ignition layer can be provided by applying two coats or layers of the protective material to provide a combined wet thickness of approximately 26 mils.

[0076] For a thermal barrier, the protective material is advantageously applied in multiple coats to build up the desired thickness. For example, the wet thickness of the protective material can be between 26 and 80 mils to provide a thermal barrier. In an advantageous embodiment of a thermal barrier, the combined wet thickness of the individual coats of the protective material is between about 50 mils to about 52 wet mils.

[0077] To achieve an ignition barrier, the material can be sprayed onto a surface such as a wall or ceiling to form a first coating. The first coating may have a sufficient thickness to provide an ignition barrier by itself. If the purpose of the protective coating is to provide an ignition barrier and a thermal barrier is unnecessary, e.g., an application in a residential structure, the first coating may be the only coating that is needed. For example, a first coating having a wet thickness of 12 mils can be used to provide an ignition barrier and be the sole coating applied to the plastic foam insulation. The ignition barrier is capable of withstanding at least 550 °F for four minutes and eighteen seconds.

[0078] If multiple coats are to be applied, the first coating is often referred to as a tack coating. If multiple coats or layers of the protective material are to be applied, the tack coating can advantageously be about 10 wet mils. In other embodiments, however, the thickness of this tack coating can vary. It is generally desirable to allow the tack coating to dry for a period of time extending several hours (e.g., 1-6 hours) before applying a second coat or layer of the protective material.

[0079] Once the tack coating has dried to a desired level, a second coating of the material can be applied. The second coating can be about 16 wet mils, for example. In other embodiments, the thickness of the second coating can be greater than 16 wet mils (e.g., particularly if the overall thickness is at least about 50 wet mils). Once the second coating has been applied, the overall thickness of the ignition barrier is formed. To achieve a thermal barrier, the material again is sprayed or applied to a surface such as a wall or ceiling to form a tack coating. The tack coating can be about 10 wet mils, for example. The tack coating can be more or less than 10 wet mils depending on the overall thickness of the thermal barrier. The tack coating is allowed to dry for several hours (e.g., 1-6 hours).

[0080] A second coating of material is applied to the surface once the tack coating dries. The second coating can be about 22 wet mils, for example, or in other embodiments the thickness can be more or less than 22 wet mils. Once the second coating is applied, it is allowed to dry for several hours (1-5 hours). After the second coating dries, a third coating of the protective material can applied to the surface. The third coating can, for example, have a thickness of about 20 wet mils. In other embodiments, the thickness can vary especially if the overall thickness of the thermal barrier is closer to 80 wet mils.

[0081] Once the thermal barrier is formed, it is able to withstand 1650 °F. In particular, it can withstand 550 °F for five minutes and then 1650 °F for at least another ten minutes.

[0082] The disclosed embodiments have been described as being applied directly to a mass of foam plastic insulation. However, alternative embodiments are also possible. For example, under some circumstances it might be desirable to apply the protective material to the plastic foam insulation with an intervening layer of material being disposed between the protective material and the foam plastic insulation. Alternatively, the protective material could be applied to another type of flammable material to thereby provide fire protection to such other material.

[0083] While exemplary embodiments incorporating the principles of the present invention have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A method of applying an ignition barrier to a structure which includes a mass of foam plastic insulation defining a surface, the method comprising:

applying at least one layer of protective material to the surface, the protective material comprising a silicate material and a liquid and wherein the at least one layer has a wet thickness of at least about 12 mils; and

allowing the protective material to dry for a period of time wherein, when dry, the protective material provides an ignition barrier for the foam plastic insulation for at least 4 minutes and 18 seconds when tested in accordance with NFPA 286.

2. The method of claim 1 wherein the layer of protective material has a total wet thickness of between about 12 mils and about 26 mils.

3. The method of claim 1 wherein the silicate material in the protective material comprises silica sand and a second material, the second material being either soda ash or potassium oxide.

4. The method of claim 3 wherein the silica sand and the second material are present in the protective material in a weight ratio of between about 1 : 1 and about 20: 1.

5. The method of claim 3 wherein the silica sand and the second material are present in the protective material in a weight ratio of about 4:1.

6. The method of claim 3 wherein the silica sand and the second material are present in the protective material in a weight ratio of about 3.22:1.

8. The method of claim 4 wherein the second material is soda ash.

9. The method of claim 4 wherein the second material is potassium oxide.

10. The method of claim 4 wherein the protective material is applied in a single layer having a wet thickness of about 12 mils.

11. The method of claim 10 wherein the second material is soda ash and the silica sand and the soda ahs are present in the protective material in a weight ratio of about 3.22 : 1.

12. The method of claim 11 wherein the protective material is about 37% solids and about 63% liquid by volume when applied.

13. The method of claim 12 further comprising the step of adding a dye to the protective material prior to applying the protective material to the surface.

14. The method of claim 13 wherein the protective material is applied directly to the surface.

15. The method of claim 14 wherein the protective material is sprayed onto the surface.

16. The method of claim 1 wherein the step of applying at least one layer of protective material to the surface comprises:

applying a tack coat layer of the protective material on the surface;

allowing the tack coat layer to dry for a period of time; and

applying a second layer of the protective material on the tack coat layer wherein the combined wet thickness of the tack coat layer and the second layer is at least about 26 mils.

17. The method of claim 16 wherein the step of applying at least one layer of protective material to the surface further comprises applying a third layer of the protective material on the second layer, wherein, when the third layer dries, the tack coat layer, the second layer and the third layer form a thermal barrier that prevents the temperature of the foam plastic insulation from exceeding the ambient temperature plus 250 °F for at least 15 minutes when tested in accordance with NFPA 286.

18. The method of claim 17 wherein the combined wet thickness of the tack coat layer, the second layer and the third layer is between about 26 mils and about 80 mils.

19. The method of claim 18 wherein the silicate material forming each of the tack coat layer, the second layer and the third layer comprises silica sand and a second material, the second material being either soda ash or potassium oxide.

20. The method of claim 19 wherein the second material is soda ash.

21. The method of claim 20 wherein, for each of the tack coat layer, the second layer and the third layer, the protective material is about 37% solids and about 63% liquid by volume when applied.

22. The method of claim 21 wherein the silica sand and the soda ash are present in each of the tack coat layer, the second layer and the third layer in a weight ratio of about 3.22:1 and the combined wet thickness of the tack coat layer, the second layer and the third layer is at least about 50 mils.

23. An ignition barrier adapted for use with foam plastic insulation defining a surface, the ignition barrier comprising: a layer of protective material disposed on the surface, the protective material comprising silica sand and a second material in a weight ratio of between about 1 : 1 and about 1:20; and

wherein the protective material provides an ignition barrier for the foam plastic insulation for at least about 4 minutes and 18 seconds when tested in accordance with NFPA 286.

24. The ignition barrier of claim 23 wherein the layer of protective material has an applied wet thickness of between about 12 mils and about 80 mils.

25. The ignition barrier of claim 24 wherein the second material is potassium oxide.

26. The ignition barrier of claim 24 wherein the second material is soda ash.

27. The ignition barrier of claim 26 wherein the layer of protective material has an applied wet thickness of between about 12 mils and about 26 mils.

28. The ignition barrier of claim 27 wherein the weight ratio of silica sand to soda ash is about 3.22:1.

29. The ignition barrier of claim 26 wherein the protective material has a thickness of at least about 50 mils and forms a thermal barrier that prevents the temperature of the foam plastic insulation from exceeding the ambient temperature plus 250 °F for at least 15 minutes when tested in accordance with NFPA 286.

30. A combination of materials for use in structure, said combination comprising:

a mass of foam plastic insulation;

a layer of protective material disposed on the surface, the protective material comprising silica sand and a second material in a weight ratio of between about 1 :1 and about 1 :20; and

31. The ignition barrier of claim 30 wherein the layer of protective material has an applied wet thickness of between about 12 mils and about 80 mils.

32. The ignition barrier of claim 31 wherein the second material is potassium oxide.

33. The ignition barrier of claim 31 wherein the second material is soda ash.

34. The ignition barrier of claim 33 wherein the layer of protective material has an applied wet thickness of between about 12 mils and about 26 mils.

35. The ignition barrier of claim 34 wherein the weight ratio of silica sand to soda ash is about 3.22:1.

36. The ignition barrier of claim 33 wherein the protective material has a thickness of at least about 50 mils and forms a thermal barrier that prevents the temperature of the foam plastic insulation from exceeding the ambient temperature plus 250 °F for at least 15 minutes when tested in accordance with NFPA 286.