Foam plasticIt seems that we use more and more plastic components as time moves forward. They are a part of construction that is not likely to go away anytime soon.
The types of plastics included in this section are as follows:
Foam plastic
Foam plastic insulation
Plastic veneer
Interior plastic finish and trim
Light-transmitting plastics.
When your package of foam plastic insulation arrives at the job site, see that the label of an approved agency is attached to the package or the container and shows the manufacturer’s name, the product listing, the product identification and any information that will be used to identify the end use with the code requirements. Both foam plastic insulation and foam plastic cores of manufactured assemblies will have a flame spread index of not more than 75. A smoke-developed index of not more than 450 must also be a characteristic of the foam insulation, and both must be in accordance with ASTM E 84. All loose fill-type foam plastic must be tested as board stock for the flame spread index and smoke-developed index. A list of exceptions is as follows:
A polymeric composite material consisting of reinforcement fibers, impregnated with a fiber-binding polymer which is then molded and hardened is a fiber reinforced polymer. |
Section 2604.2 contains the smoke-developed index for interior trim.
In buildings that are used as cold storage, like ice plants, food plants, or food processing rooms, where insulation is tested in a thickness of 4 inches, insulation will be allowed in a thickness up to 10 inches if the building is equipped throughout with an automatic fire sprinkler.
Roof-covering assemblies such as Class A, B, or C that contain foam plastic insulation provided that the insulation passes FM 4450 or UL 1256
Foam plastic insulation that is greater than 4 inches in thickness must have a maximum flame index of 450 when tested at a minimum thickness of 4 inches.
Flame spread and smoke-developed indexes for foam-developed plastic interior signs in covered mall buildings provided the signs comply with Section 402.15.
With the exceptions of masonry and concrete construction, and cooler and freezer walls, foam plastic must be separated from the inside of the building by a thermal barrier of ½-inch gypsum wallboard. This is to limit the average temperature rise of the unexposed surface to no more than 250°F after 15 minutes of fire exposure, complying with the standard time-temperature curve of ASTM E 119. As stated previously, no thermal barrier is needed in masonry or concrete construction. This is true if the concrete wall, floor, or roof system is covered on each face by a minimum of 1-inch thickness of masonry or concrete. Nor is a thermal barrier required for cooler and freezer walls that are installed with foam plastic with a thickness of 10 inches. Cooler and freezer walls must:
Have a flame spread index of 25 or less with a smoke-developed index of no more than 450
Have flash ignition and self-ignition temperatures of no less than 600°F to 800°F
Have a covering of no less than 0.032-inch corrosion-resistant steel with a base metal thickness no less than 0.0160 inch at any point
Be protected by an automatic sprinkler system
A cooler or freezer within a building must also be part of the building protected by sprinklers.
In one-story buildings that have a foam plastic with a flame spread index of less than 25, cooler and freezer walls are not required to have a thermal barrier in or on outside walls in a thickness no more than 4 inches thick. This is only true where the foam is covered by a no less than 0.032-inch-thick aluminum steel with a base thickness of 0.0160 inch. The building must be fully equipped throughout with an automatic sprinkler system. Foam plastic insulation mounted in accordance with both the code and the manufacturer’s instructions must be separated from the inside of the building with a wood panel sheathing no less than 0.47 inch thick and bonded with exterior glue.
The following list contains the provisions for doors that are not required to have a fire protection rating:
Pivoted or side-hinged doors having a flame spread index of 75 or less are allowed as a core material.
For exterior doors in buildings of Group R-2 or R-3, foam-filled entrance doors must be faced with wood or another approved material.
Garage doors with foam plastic used as core materials must have a door facing of metal with a thickness of 0.032 inch.
There is an exception for garage doors using foam plastic insulation and the compliance with Section 2603.3 in regards to detached and attached garages of one- and two-family dwellings that exempt them from the thermal barrier requirement. Anytime that foam plastic is used as interior trim, and compliance with Section 2604 is met, a thermal barrier is not needed. This also is true for interior signs that comply with Section 402.15. However, be aware that foam plastic signs that are not attached to the interior of a building must comply with the International Fire Code.
Foam plastic insulation, exterior coatings and facings all must be tested separately for the thickness intended for use, flame index spreads, and smoke-developed index. ASTM E 84 has determined that the flame index spread for all three cannot be more than 25 with a smoke-developed index of less than 450. However, prefabricated or factory-manufactured panels can be tested as an assembly as long as the foam plastic core is not exposed during construction and only if panels have a minimum thickness of 0.020-inch aluminum facing and a total thickness of 0.25 inch or less.
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When you apply foam plastic spray to a sill plate and header of Type V construction there are three requirements that must be met. Plastic foam spray must have a maximum thickness of 3¼ inches, foam plastic must have a density range of 1.5 to 2.0 pcf, a flame spread index of 25 or less, and a smoke-developed index of 450 or less when tested with ASTM E 84. |
There has been a change in this code regarding the use of foam plastics and the protection against termites.
It is now known that termites have a huge tendency to burrow through expanded polystyrene and other foam plastics to get to wood. Therefore, you cannot install exterior foam plastics below grade. There are a few exceptions as follows:
In buildings where walls, floors, and ceilings are made of wood treated with a preservative or noncombustible materials
When there has been an approved method used to protect foam plastic and structures from termite damage
On the inside of basement walls.
Foam plastics are not required to comply with Sections 2603.4 through 2603.7 if approval has been met through testing. This testing is not limited to NFPA 286, FM 4880, UL 140, or 1715, and any testing must be in relation to the use of the foam plastic. When allowed for use as an interior finish—and only on the basis of special testing will this be allowed. Testing will include seams, joints, and other details typically used for this type of installation. Testing must also include the manner intended for use.
Plastic materials must comply with this section when installed as interior finish and trim. Also refer to the last sentence of the above paragraph as a reminder of special approval. When and if you receive special approval to use plastic materials for trim you must also comply with the following:
Interior trim must have a minimum density of 20 pcf.
Interior trim must have a maximum thickness of ½ inch with a maximum width of 8 inches.
There will be an area limitation of no more than 10 percent of the aggregate wall and ceiling area of any room or space.
When tested in accordance with ASTM E 84, the flame spread index will not be more than 75.
No limitation is made on the smoke-developed index.
Plastic veneer used inside of a building must be in compliance with interior finish and trim. You are allowed to install exterior plastic veneer on the exterior walls of buildings and are not restricted to the type of construction; however, there are guidelines that must be met. See the following list for these guidelines:
Plastic veneer must comply with Section 2606.4.
Do not attach plastic veneer to any outside wall with a height of more than 50 feet above grade.
There is a 300 square foot minimum for sections of plastic veneer with a separation minimum of 4 feet.
Note that the area and separation requirements and the smoke-density limitation do not apply to Type VB construction, provided that there is not a fire-resistance rating requirement for walls.
Before any light-transmitting materials are used, you must first submit, for approval, sufficient data to demonstrate the use of such materials. It is up to the building official to allow the use of light-transmitting materials in your building or structure. Light-transmitting plastics include thermoplastic, thermosetting, or reinforced thermosetting plastic materials, and all of these must have a self-ignition temperature of 650°F or higher when tested in accordance with ASTM D 1929.
CODE UPDATE |
Foam plastics installed as trim must not constitute more than 10 percent of the specific wall or ceiling areas to which it is attached. |
The smoke-developed index cannot be greater than 450 when tested in accordance with ASTM E 84, or greater than 75 when tested in accordance with ASTM D 2843. All light-transmitting materials must conform to either Class CC1, in which plastic materials have a 1 inch or less burning extent when tested at a thickness of 0.060 inch, or Class CC2, in which plastic materials have a burning rate of 2½ inches per minute when tested at a thickness of 0.060 inch. Both classes must be tested in accordance with ASTM D 635.
Light-transmitting plastic materials must comply with provisions regarding the durability of strength and loads. The building official will use any data that establishes stresses, maximum weight spans, and other important information in making decisions regarding the use of light-transmitting plastics. Submission of this information and data is mandatory on your part; without doing so, you will not have approval from the building official.
There are certain occupancies and locations in which a light-diffusing system cannot be installed without an automatic sprinkler system. These occupancies and locations are as follows:
Group A occupancies with an occupant load of 1000 or more
Theaters with a stage and proscenium opening and an occupant load of more than 700
Group I-2 and I-3 occupancies
Stairways and passageways intended for exits.
Hangers of at least No. 12 steel must be used as support for light-transmitting diffusers. These must be hung directly or indirectly from ceilings or roof construction and the hangers must be made of a noncombustible material. Be sure that you are in compliance with the code, unless the plastic diffusers have the ability to fall from their mountings before ignition takes place at a temperature of 200°F; this temperature is below the ignition temperature of panels. Please note that panels cannot be more than 10 feet in length or 30 square feet in length.
You are allowed, by this code, to install light-transmitting plastics as glazing in shower stalls, doors, and bathtub enclosures as long as you are in compliance with Glass and Glazing.
You cannot use light-transmitting plastic as wall panels in exterior walls in occupancies of the following groups.
A-1
A-2
H
I-2
I-3.
This is allowed in other groups, but only if the walls are not required to have a fire-resistance rating, and installation conforms to this section. For instance, exterior wall panels cannot alter the type of construction.
Lastly, the combining of light-transmitting plastic glazing and light-transmitting plastic wall panels is subject to height, area, and percentage limitations along with any separation requirements.
Be reminded that there are provisions regarding the protection for openings in exterior walls of Type VB construction. However, areas that are not required to comply are permitted to have light-transmitting plastic as long as it in compliance with its proper section of this chapter and also in accordance with the following.
The total area of the plastic glazing cannot be more than 25 percent of any area of any wall face of the story in which it is installed, except for those areas that have an automatic sprinkler system; only then can the total area be increased to a maximum of 50 percent.
Installation of an approved flame barrier between glazed units in adjacent stories is allowed and it must extend 30 inches beyond the outside wall or a vertical panel no less than 4 feet. An exception to this is a building equipped throughout with an automatic sprinkler system.
Do not install light-transmitting plastics more than 75 feet above grade plane. Again, an exception to this is a building equipped throughout with an automatic sprinkler system.
Such panels cannot be installed in Groups H, I-2, and I-3. You may install them in other groups as long as they comply with any one of the following conditions.
The building has an automatic sprinkler system throughout.
The roof is not required to comply with the fire-resistance rating
Roof panels meet the requirements for roof coverings.
Roof panels are required to be limited in area, and the total area of panels is limited by a percentage of the floor area. The following list of exceptions address this provision.
Area limitations are increased by 100 percent if the building has an automatic sprinkler system.
Low-hazard occupancy buildings are exempt from limitations provided that the buildings are no larger than 5000 square feet with a minimum fire separation distance of 10 feet.
Greenhouses without public access are exempt from area limitations, but only if they have a minimum fire separation distance of 4 feet.
CODE UPDATE |
Light-transmitting plastic covers on solar collectors having noncombustible sides and bottoms shall be permitted on buildings not over three stories above grade plane of 9000 square feet in total floor area, provided the light-transmitting plastic cover does not exceed one third of the roof area for CC1 materials or 25 percent of the roof area for CC2 materials. |
Roof coverings of terraces and patios in Group R-3 occupancies are permitted to have light-transmitting plastics.
This section provides the provisions for skylight assemblies with light-transmitting plastics. If installing unit skylights glazed with light-transmitting plastic, refer to the code book for compliance requirements. This provision does not include skylights that contain light-transmitting plastics that already conform to code. It is ruled that light-transmitting plastics be set upon curbs that have been constructed above the plane of the roof by at least 4 inches. Make sure that all edges are protected by metal or another material that has been approved for protective use.
Any material you use must be ignition resistant to exposure of flames. Curbs are not required for skylights that are used on roofs with a minimum slope of three units vertical in 12 units horizontal. This pertains to occupancies in Group R-3 and for buildings that have a noncombustible roof covering. Also, metal or noncombustible edge materials are not required where non-classified roof coverings are allowed.
There is a maximum of 100 square feet within the curb area that skylights must have; however, this area limitation does not apply to buildings equipped with an automatic sprinkler system. Make sure that you have placed all your skylights with a distance of no less than 4 feet measured in a horizontal plane.
Buildings with automatic sprinkler systems and Group R-3 occupancies with more than one skylight that do not exceed the area limitations in this section are not included in the separation provisions.
Light-transmitting plastic interior signs must follow the provisions of the code and cannot have an area more than 20 percent of the wall area with a maximum area of 24 square feet. The edges and backs of all plastic interior signs must be fully encased in metal.
