TAB TRACK FIRE-RATED WALL ASSEMBLY WITH DYNAMIC MOVEMENT
20180195282 ยท 2018-07-12
Inventors
Cpc classification
E04B2002/0289
FIXED CONSTRUCTIONS
E04C2/205
FIXED CONSTRUCTIONS
E04B2/767
FIXED CONSTRUCTIONS
International classification
E04B2/78
FIXED CONSTRUCTIONS
Abstract
A fire-rated head-of-wall assembly includes a header track having bendable tabs, a pair of which is configured to hold a wall stud in place relative to the header track. An upper wallboard piece abuts against the ceiling and a lower wallboard piece is spaced from the upper wallboard piece to form a gap. A fire-resistant material, such as mineral wool, is positioned within the gap. An outer wallboard piece spans across the gap.
Claims
1. A fire-rated wall assembly configured to seal a deflection gap in a head-of-wall joint, comprising: a footer track; a plurality of wall studs; an elongated sheet-metal header track configured to hold the plurality of wall studs in place relative to the header track, the header track comprising a web and a first leg and a second leg, the first and second legs extending in the same direction from opposite edges of the web in a general U-shape; a ceiling; an upper wallboard piece adjacent to the first leg and contacting the ceiling; a lower wallboard piece adjacent to the plurality of wall studs, the lower wallboard piece spaced from the upper wallboard piece; a gap formed between the upper and lower wallboard pieces; a fire-resistant material positioned within the gap; an outer wallboard piece spanning across the gap and positioned next to the upper and lower wallboard pieces; wherein during dynamic movement of the fire-rated wall assembly, the header track moves with the ceiling and the plurality of wall studs move with the footer track such that the gap lengthens and shortens.
2. The fire-rated wall assembly of claim 1, wherein the header track includes bendable tabs, the tabs configured to hold the plurality of wall studs in place relative to the header track.
3. The fire-rated wall assembly of claim 1, wherein the fire-resistant material is mineral wool.
4. The fire-rated wall assembly of claim 1, wherein the fire-resistant material is a compressible intumescent foam.
5. The fire-rated wall assembly of claim 1, wherein the fire-resistant material is a backer rod.
6. The fire-rated wall assembly of claim 1, wherein the gap is adjacent to the plurality of wall studs.
7. The fire-rated wall assembly of claim 1, further comprising an intumescent strip attached to the web of the track.
8. The fire-rated wall assembly of claim 1, wherein the outer wallboard piece and the lower wallboard piece are fastened to the plurality of wall studs and the upper wallboard piece is fastened with the first leg of the header track.
9. The fire-rated wall assembly of claim 1, further comprising: a second upper wallboard piece adjacent to the second leg and contacting the ceiling; a second lower wallboard piece adjacent to the plurality of wall studs, the second lower wallboard piece spaced from the second upper wallboard piece; a second gap formed between the upper and lower wallboard pieces; a second fire-resistant material positioned within the gap; a second outer wallboard piece spanning across the second gap and positioned next to the second upper and second lower wallboard pieces.
10. A fire retardant head-of-wall assembly configured to seal a linear head-of-wall construction joint or gap during dynamic movement, comprising: a ceiling; a header track coupled with a plurality of wall studs, the header track comprising a web and first and second legs extending therefrom; a rip of wall material extending along the first leg of the header track; an inner layer of wall material coupled with the plurality of wall studs, the inner layer located below the rip; a gap formed between the rip and the inner layer; an outer layer of wall material spanning across the gap and extending along the rip.
11. The head-of-wall assembly of claim 10, wherein an upper face of the rip contacts the ceiling and the gap is formed between a lower face of the rip and an upper face of the lower layer.
12. The head-of-wall assembly of claim 11, wherein the lower face of the rip extends to and is level with a lower edge of the first leg of the header track.
13. The head-of-wall assembly of claim 10, further comprising: a second rip of wall material extending along the second leg of the header track; a second inner layer of wall material coupled with the plurality of wall studs, the second inner layer located below the second rip; a second gap formed between the second rip and the second inner layer; a second outer layer of wall material spanning across the second gap and extending along the second rip.
14. The head-of-wall assembly of claim 10, further comprising a fire-resistant material within the gap.
15. The head-of-wall assembly of claim 14, wherein the fire-resistant material is a compressible fire-resistant material.
16. The head-of-wall assembly of claim 14, wherein the fire-resistant material is one of a mineral wool, an intumescent foam, a polyurethane foam, a backer rod or a flexible vinyl profile.
17. A metal stud and gypsum drywall assembly, comprising an upper drywall board coupled with a ceiling by a header track and a lower drywall board coupled with a plurality of metal studs slidingly engaged with the header track, the ceiling configured to move with respect to the plurality of metal studs, an outer drywall board overlapping the upper and lower drywall boards to maintain a fire rating across the metal stud and gypsum drywall assembly.
18. The wall assembly of claim 17, further comprising a gap between the upper drywall board and the lower drywall board, the gap located below the header track and extending horizontally and parallel with the header track, the gap configured to accommodate movement between the upper and lower drywall boards, a compressive fire-resistant material filling the gap to provide sound absorption, fire protection and allow movement while being concealed by the outer drywall board.
19. The wall assembly of claim 18, wherein the upper drywall board is coupled with a leg of the header track, the header track having a general U-shape and the lower drywall board coupled with the outer drywall board, an upper face of the outer drywall board extending towards the ceiling to conceal the gap.
20. The wall assembly of claim 19, comprising a second upper drywall board coupled with a second leg of the header track, a second lower drywall board coupled with the plurality of metal studs, a second gap between the second upper drywall board and the second lower drywall board, a second compressive fire-resistant material disposed within the second gap, a second outer drywall board overlapping the second upper and second lower drywall boards to maintain a fire rating across the metal stud and gypsum drywall assembly and to conceal the second gap.
Description
BRIEF DESCRIPTION
[0043] Certain features, aspects and advantages of the various devices, systems and methods presented herein are described with reference to drawings of certain embodiments, which are intended to illustrate, but not to limit, such devices, systems, and methods. It is to be understood that the drawings are for the purpose of illustrating concepts of the embodiments discussed herein and may not be to scale. For example, certain gaps or spaces between components illustrated herein may be exaggerated to assist in the understanding of the embodiments. Dimensions, if provided in the specification, are merely for the purpose of example in the context of the specific arrangements shown and are not intended to limit the disclosure.
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DETAILED DESCRIPTION
Track Framing Assemblies
[0067] Several preferred embodiments provide a way to secure metal studs to the header track or bottom track without using mechanical screw fasteners. The C- or U-shaped header or bottom track includes a plurality of slits in one or both flanges of the track that form a plurality of tabs in the flanges of the track adjacent the free edge of the flanges. The slits extend partially up the legs or flanges of the track so that the bulk of the track is a solid uninterrupted C- or U-shape profile. The track can, in some embodiments, have fire-retardant material such as intumescent strips added to the surface of the back web of the track to provide fire rated wall assemblies according to UL-2079.
[0068] Referring to
[0069] As further illustrated in
[0070] With reference to
[0071] The track 10 can be constructed of any suitable material by any suitable manufacturing process. For example, the track 10 can be constructed from a rigid, deformable sheet of material, such as a galvanized light-gauge steel. However, other suitable materials can also be used. The track 10 can be formed by a roll-forming process. However, other suitable processes, such as bending (e.g., with a press brake machine), can also be used. Preferably, the fire-retardant material(s) 38 are applied during the manufacturing process. However, in some applications, the fire-retardant material(s) 38 could be applied after manufacturing (e.g., at the worksite).
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[0075] The slits 30 extend approximately of the way up each flange 224, 226 as measured from the free end of the flanges 224, 226. As shown, the slits 30 extend partially along the width or height of the flanges 224, 226 of the track 210 so that the bulk of the track 210 (preferably the upper portion) is a solid uninterrupted U- or C-shaped profile to prevent sound, smoke, or light from passing through the head-of-wall or bottom-of-wall joint. In some embodiments, the slits 30 extend one-third () of width or height of the flanges 224, 226 as measured from the free end of the flanges. Additionally, the track 210 allows the drywall to be installed tight and flush against the wall framing members because no mechanical fastener is used to attach the stud 18 to the track 210. As illustrated in
[0076] The slits 30 on the track 210 can be made from a rotary die. Use of a rotary die provides consistency to the manufacture of the slits 30. A rotary die can also be used to provide an embossed marking along the flanges 224, 226 of the track 210 for stud layout, as discussed above with respect to the embossed vertical indicators shown in
[0077] The upper portion of each slit 30 has a round key hole 32 to enable the tabs 228, 229 to bend. In some embodiments, a width of the key hole 32 is up to or equal to twice the width of the slit 30. The key hole 32 provides flexibility to allow the tabs 228, 229 to move inward and outward easily without distorting the profile or leg of the track 10. Additionally, a round key hole 32 allows the flange 224, 226 to remain flat when the tabs 228, 229 are pushed in to secure a stud. While a round key hole 32 is illustrated in
[0078] Preferably, in some embodiments, as shown in
[0079] As discussed above, the track provides a series of pre-bent tabs that provide flexibility and allow the vertical studs numerous locations to lock in place in the track and prevent lateral side to side movement of the stud. To move the stud to a different location, the installer can rotate the stud a half turn which will release the stud out of the restrictions of the tabs. Alternatively, the installer can bend the tabs downward, upward and/or outward to free up the stud. In some embodiments, track can be manufactured with the tabs straight and not pre-bent. When the tabs are not pre-bent, the vertical studs can still be placed anywhere within the series of tabs of the track; however, in this configuration, to engage the stud, the tabs are physically bent by hand or tapped with a hammer on each side of the stud to bend the tabs inward to grip or hold the stud in place and prevent side to side lateral movement of the stud. Pre-bending the tabs during manufacture of the track allows the installer to place and lock-in the studs within the framed wall assembly on layout from the ground and preferably does not require the installer to use a bench or scaffolding to access the top of the wall header track in order to physically push in the tabs on either side of the stud or to mechanically fasten the track to the stud. Any of the embodiments disclosed herein can have pre-bent or straight tabs, or a combination of the two.
[0080] Another embodiment of a track with tabs is illustrated in
[0081] Another embodiment of a track with tabs is illustrated in
[0082] Tenant Improvement or TI construction is typically used in office build outs. Light gauge steel framing is very common in TI construction. In this type of construction, the steel header track is typically attached directly to the underside of the t-bar ceiling. T-bar ceilings are allowed to float as they are attached with wire hangers to the floor structure above. Floating ceilings need to maintain their flexibility throughout the ceiling so direct attachment of the wall studs and track to a floating ceiling will only make the ceiling and wall more rigid. The more rigid the wall, the more likely sound will pass through the wall. Therefore, it is desirable to have a flexible wall connect to a floating ceiling so that both the wall and the ceiling can maintain their flexibility. The embodiments of the track discussed above provide that flexibility because the studs are only gripped into place by the tabs of the track and are not hard-attached to the track (e.g., by mechanical fasteners). This allows the track the flexibility to move up and down with the ceiling. In order to provide additional sound protection, an adhesively-backed foam tape 39 such as 3M SC URETHANE FOAM TAPE can be factory taped to the track (as shown in
Fire-Rated Head-of-Wall Assemblies
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[0084] The assembly 500 can provide for both fireblocking and sound dampening between opposite sides 581, 582 of the assembly 500 (e.g., through the deflection gap 501). As noted above, local building codes commonly require certain types of building joints be fire-resistive or fire-stopped as a form of passive fire resistance for the building. The head-of-wall assembly 500 can provide fire resistance (e.g., fire, sound, smoke, or light passage resistance) between opposite sides 581, 582 (e.g., through the deflection gap 501), as described below.
[0085] A header track 510 can be attached with the ceiling 516 and receive the one or more studs 518. The header track 510 can be any header track constructed from any suitable material, including the tabbed header tracks 10, 210, 310, 410 described above.
[0086] Some existing head-of-wall assemblies change the standard U-shape profile of the header track. An example of this is the FIRE TRAK header track (U.S. Pat. Nos. 5,471,805 and 5,755,066). The FIRE TRAK header track relies on a special track profile that is wider and requires the track legs to be longer and include an offset segment. The FIRE TRAK also needs an additional clip to attach the stud to the track whereas the tabbed header tracks described above (e.g., header tracks 10, 210, 310, 410) can set the studs into the track by utilizing the retention feature of the tab track legs without an additional clip.
[0087] One advantage of the assembly 500 is that it can incorporate a standard U-shaped header track. The header track 510 can include a web 522 and a pair of flanges 524, 526 extending therefrom. The stud 518 can be received within a generally U-shaped channel created by the web 522 and flanges 524, 526 and secured within the header track 510 (e.g., by the tabs 28, 29 of the header track 10). The flanges 524, 526 can be slotted where coupled with the stud 518 to allow for movement therebetween in the vertical direction.
[0088] In some implementations, the stud 518 can be any suitable wall stud (e.g., wood, sheet metal, or other). In some implementations, the stud 18 can be received within and secured to the header track 510 using any suitable techniques, including mechanical fasteners such as nail, screws, and the plurality of tabs 28, 29 described above. In some implementations, the stud 518 can be received within and secured to the header track 510 at any point along a length of the header track 510. The assembly 500 can include a plurality of studs 518 that provide support to one or more wallboards forming opposite sides 581, 582 of the wall assembly 580, as described further below.
[0089] The assembly 580 can include a rip of wallboard material 532. The rip 532 can be a strip of material attached with a side of the flange 526 of the header track 510. The rip 532 is generally attached with the header track 510 by one or more screws 530. In other implementations, the rip 532 can be attached using any conventional techniques, including mechanical fasteners 30 (e.g., screws, nails, tabs, hooks or other) or adhesives.
[0090] In certain implementations, the header track 510 (e.g., tabbed track 10) is U-shaped or substantially U-shaped in profile with no offsets or significant offsets or indentations on the flanges 526, 524. The flanges 524, 526 can thus provide a desirable surface to attach a rip of drywall (e.g., rip 532) to the header track 510. The rip 532 will be able to stay in line with and extend along the header track 510 and maintain the deflection gap 501.
[0091] In some implementations, the rip 532 is an approximately 2-inch wide strip of wallboard material (e.g., gypsum or drywall panels, wood or other suitable wallboard materials). In some implementations, the rip 532 can be approximately 2-4 inches wide, or any sub-range or value within this range. The rip 532 can extend the length of the header track 510 (e.g., along an entire length of the assembly 500). An upper surface of the rip 532 can be abutted against the ceiling 516 to partially or completely block the passage of smoke, sound and/or light between the header track 510 and the ceiling 516. In some implementations, an intumescent strip can be included between the ceiling 516 and the upper surface of the rip 532 or the web 522 of the header track 510. In some implementations, the rip 532 can extend the width and length of the flange 526 to which it is attached, thereby completely covering the flange. In some implementations the rip 532 is less wide than or wider than the flange 526 (e.g., a lower face of the rip 532 is above or below a distal edge of the flange 526). For stability, the rip 532 can extend to only just past the distal edge (e.g., 0 inches to 2 inches).
[0092] On the first side 581, the assembly 500 can include an inner layer 534 of wallboard material and an outer layer 536 of wallboard material. The inner and outer layers 534, 536 can be formed of any suitable wallboard material or paneling, including gypsum drywall. The inner layer 534 and/or the outer layer 536 can be attached to the stud 518 (and any other adjacent studs) using conventional mechanical fastening techniques. For example, a plurality of metal or drywall screws can extend through the inner and/or outer layers and couple with the one or more studs 518.
[0093] The inner layer 534 can be spaced below the rip 532 leaving a horizontal gap 539. The horizontal gap 539 can extend from a bottom face of the rip 532 to a top face of the inner layer 534. Preferably, the dimension of the horizontal gap 539 in the vertical direction of the wall 580 is sufficient to accommodate complete movement allowed by the deflection gap 501. Thus, the horizontal gap 539 can be as large as or larger than the deflection gap 501 in the vertical direction. In some implementations, the horizontal gap 539 can be approximately 1-inch wide (e.g., vertically) between the rip 532 and the inner layer 534, depending on the position of the dynamic head-of-wall assembly 500. In some implementations, the horizontal gap 539 can be approximately 1-2 inches wide, or any sub-range or value within this range. The horizontal gap 539 can be approximately the depth of the thickness of the rip 532 and/or inner layer 534 (plus any additional depth between the stud 518 or header 510 and the inner layer 534 or rip 532). In some implementations, the depth can be approximately , , or any other suitable depth.
[0094] On the second side 582, another outer wall 546 of wallboard material can be assembled with the wall 580. The outer wall 546 can be coupled with the one or more studs 518 using conventional fastening techniques. The deflection gap 501 can extend between an upper face of the outer wall 546 and the ceiling 516. The flange 524 of the header track 510 can be positioned between at least a portion of the outer wall 546 and the stud 518.
[0095] The horizontal gap 539 can be left unfilled, in some implementations. In other implementations, however, the horizontal gap 539 can be filled with fire-resistant material 538. The first resistant material can include mineral wool, fiberglass, compressible intumescent foam, backer rod, or other types of compressible or expanding fire-resistant materials. The mineral wool can be stone mineral wool or glass mineral wool, such as that manufactured by ROXUL Inc., THERMAFIBER Inc., or any other manufacturer of suitable mineral wool.
[0096] Mineral wool also has proven sound absorption qualities that have never been utilized within layers of drywall in a wall assembly 580. By placing the mineral wool within the wall assembly 580 one can take advantage of the fire rating and the sound rating properties of mineral wool, as well as its compressible nature making it highly suitable for dynamic joints. The wall assembly 580 can also incorporate mineral wool (or other fire-resistant material) between concealed drywall panels (e.g., between the first and second sides opposite 581, 582).
[0097] In some implementations an intumescent angle fire block (e.g., CEMCO Deflection Drift Angle (DDA) as described in US2017/0175386, the entirety of which is hereby incorporated by reference) can be installed on the header track 510 (e.g., on one or both of the flanges 524, 526). The rip 532 can be installed and assembled with the header track 510 over the intumescent angle fire block. Fire-resistant material 538 will allow the horizontal gap 539 to open and close and still provide fire protection across the wall assembly 580. In some implementations, the header track 510 can also have one or more intumescent strips added between the ceiling 522 and the web 522 to provide an additional layer of fire and/or sound protection.
[0098] The outer layer 536 can span across the horizontal gap 539 and be positioned next to the rip 532 and/or the lower layer 534 in both the open and closed positions. This can provide continuity to the general appearance of the assembly 500 (e.g., floating ceiling architectural design) while maintaining the fire-resistant barrier. For example, the outer layer 536 can span across the horizontal gap 539 and maintain the fire-resistant material 538 therein throughout dynamic movement of the assembly 500. In some implementations, an inner surface of the outer layer 536 slidingly engages with an outer surface of the rip 532. In some implementations, the rip 532 and the inner layer 534 have the same thickness (e.g., are made from the same material, such as or gypsum board) such that the outer layer 536 does not contact and/or is offset from the rip 532 (e.g., offset between approximately 1/64 to ).
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[0100] In some implementations, when the assembly 580 is in the closed position the fire-resistant material 539 or other compressible material is compressed in the gap 538 between the upper face of the inner layer 534 and the lower face of the rip 532. An upper face of the outer layers 536, 546 can contact with or abut the ceiling 516, in some implementations, although this is an optional arrangement. In some implementations, in the open position, the fire-resistant material 539 or other compressible material seals off the gap/joint in the drywall and protects against smoke, fire, and sound passage across the assembly 500.
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[0102] The wall assembly 600 can include a ceiling 616, header track 610, one or more studs 618 and a wall assembly 680. The wall assembly can have opposite sides 681, 682. The first side 682 can have a rip 632 coupled with a flange 624 of the header track 610. An inner layer of wallboard material 634 couples with the stud 618 below the rip 632 to create a gap 639. The gap 639 can accommodate dynamic movement of the assembly 600. A fire resistant material 638 can be disposed in the gap 639. An outer layer of wallboard material 636 spans across the gap and is positioned next to the rip 632 of drywall and the inner layer of drywall 634.
[0103] The second side 682 can have a rip 642 coupled with a flange 626 of the header track 610. An inner layer of wallboard material 644 couples with the stud 618 below the rip 642 to create a gap 649. The gap 649 can accommodate dynamic movement of the assembly 600. A fire resistant material 648 can be disposed in the gap 649. An outer layer of wallboard material 646 spans across the gap 649 and is positioned next to the rip 642 of drywall and the inner layer of drywall 644. One or more intumescent strips 625 can be attached between a web 622 and the ceiling 616 for additional fire-blocking.
[0104] In some configurations, when the joint is in the closed position the mineral wool or other fire-resistant materials 638, 648 are compressed in the joint, Upper faces of outer layers of drywall 636, 646 can be generally in contact with or abut the ceiling 616. In some implementations, in the open position the mineral wool or other fire-resistant material expands to fill the gaps 639, 649 and create a seal between the rip 632, 642, the inner layer of wallboard material 634, 644 and the outer layer of wallboard material 636, 646 on each opposite side 681, 682 of the wall assembly 680.
[0105] Traditional head-of-wall assemblies that provide dynamic movement are located at the very top of wall adjacent to the overhead structure. The problem with head-of-wall joints with deflection gaps that are at the very top of the wall is that the gaps are typically fully exposed and must be filled with fire sealant. The fire sealant is attached to the overhead structure and the edge of the drywall. When the joint moves as it is intended to do, the fire sealant (e.g., caulking) will likely split, crack and pull away from the edge of the drywall over time leaving the fire rated joint vulnerable to fire, smoke and sound passage. Moreover, application of the fire sealant can be inconsistent, leading to the risk of failed inspections.
[0106] Locating a gap (e.g., gaps 539, 639, 649) below the flanges of the header track that are covered by an outer layer of drywall will allow the dynamic joint to be concealed, as done in assemblies 500, 600. Filling these gaps with fire-resistant/compressible material that will not breakdown over time can create a long-lasting dynamic head-of-wall assembly that can block the direct passage of fire and still provide flexibility across joint without compromising the fire protection and without requiring application of caulking or sealants.
Limits of the Disclosure
[0107] Although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In particular, while the present fire-block device, system and method has been described in the context of particularly preferred embodiments, the skilled artisan will appreciate, in view of the present disclosure, that certain advantages, features and aspects of the device, system and method may be realized in a variety of other applications, many of which have been noted above. Additionally, it is contemplated that various aspects and features of the invention described can be practiced separately, combined together, or substituted for one another, and that a variety of combination and subcombinations of the features and aspects can be made and still fall within the scope of the invention. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims.
[0108] It should be emphasized that many variations and modifications may be made to the herein-described embodiments, the elements of which are to be understood as being among other acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims. Moreover, any of the steps described herein can be performed simultaneously or in an order different from the steps as ordered herein. Moreover, as should be apparent, the features and attributes of the specific embodiments disclosed herein may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure.
[0109] Conditional language used herein, such as, among others, can, could, might, may, e.g., and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment.
[0110] Moreover, the following terminology may have been used herein. The singular forms a, an, and the include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to an item includes reference to one or more items. The term ones refers to one, two, or more, and generally applies to the selection of some or all of a quantity. The term plurality refers to two or more of an item. The term about or approximately means that quantities, dimensions, sizes, formulations, parameters, shapes and other characteristics need not be exact, but may be approximated and/or larger or smaller, as desired, reflecting acceptable tolerances, conversion factors, rounding off, measurement error and the like and other factors known to those of skill in the art. The term substantially means that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
[0111] Any dimensions disclosed herein or included in the accompanying drawings are by way of example only unless specifically claimed. Numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also interpreted to include all of the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of about 1 to 5 should be interpreted to include not only the explicitly recited values of about 1 to about 5, but should also be interpreted to also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3 and 4 and sub-ranges such as about 1 to about 3, about 2 to about 4 and about 3 to about 5, 1 to 3, 2 to 4, 3 to 5, etc. This same principle applies to ranges reciting only one numerical value (e.g., greater than about 1) and should apply regardless of the breadth of the range or the characteristics being described. A plurality of items may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. Furthermore, where the terms and and or are used in conjunction with a list of items, they are to be interpreted broadly, in that any one or more of the listed items may be used alone or in combination with other listed items. The term alternatively refers to selection of one of two or more alternatives, and is not intended to limit the selection to only those listed alternatives or to only one of the listed alternatives at a time, unless the context clearly indicates otherwise.