By Gregory Havel
The idealroof覆盖难以点燃。在过去的几个世纪里，这一概念被证明在燃烧过程中，当余烬上升在热柱上时，在风中落在风中，落在距离的屋顶上，并点燃那些可燃的人。
消防评级roofcoverings are tested by ASTM E-108, UL 790, and National Fire Protection Association (NFPA) 276,用于确定具有甲板上屋顶部件的可燃组件的屋顶组件的散热速率的火灾试验方法，2011年版。这些标准根据他们的能力将屋顶覆盖物分类为A类，B类，C类或“无关”：
- resist the spread of fire into the attic;
- 抵抗屋顶覆盖物的火焰蔓延;和
- resist the generation of burning embers.
A级roofcoverings are noncombustible like tile, metal, and slate. An example of a Class B roof covering is fire retardant-treated wood shingles. An example of an “unrated” roof covering is plain wood shingles. However, a Class B roof covering may receive a Class A rating if it is installed as part of a system that includes additional fire-resistive elements in the assembly. These four classes of roof coverings are incorporated into most building and some fire codes, and are usually noted on the manufacturers’ literature and materials labels.
Please note that the Class A, B, and C ratings for roof coverings are related neither to the Class A, B, and C flame spread/smoke developed ratings of ASTM E-84/UL 723; nor to the hourly fire-resistance ratings of structural assemblies of ASTM E-119.
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Pitched roofs can be finished with a variety of roof coverings. These include:
- 木形带状疱疹（照片1）是可燃的，但可以用阻燃化学品在轧机上处理。然而，这些化学物质的阻燃性能变得越来越有效，并且如果涂层或染色，则可以克服。
- 沥青瓦片或卷屋顶由沥青制成，具有天然纤维或玻璃纤维毡，可燃。这些与矿物砂砾（如沙子）浮出水面，给予它们颜色并使表面不那么可燃。
- 瓷砖屋顶（照片2）采用重叠和互锁的Terra Cotta或混凝土瓷砖制成，不可燃烧。瓦片屋顶在完整时提供了不稳定的脚，并且在湿润时变得滑，并且当覆盖着碎片的破碎的瓷砖时不可能通风。
- Slate roofs (photo 3) are made of overlapping slates: noncombustible natural stone that has been split into thin layers to make roofing materials. These roofs provide precarious footing when intact and become slippery when wet or covered with moss; they become impossible when covered with broken pieces of slate that were removed for通风。
- Metal roofs (photo 4) are noncombustible and can often be cut with an ax or power saw at the same time as the wood-roof sheathing to which they are usually attached for vertical ventilation. They provide precarious footing when intact and become slippery when wet. Metal roofing materials are sometimes applied over other types of original roofing materials when they have reached the end of their effective life.
木材和沥青瓦片和它们所附的木材屋顶护套易于切割轴或电源锯，使垂直通风在具有这些类型的屋顶的结构中选择。
板岩和瓷砖难以用斧头或电源锯切件。它们必须用Maul或A斧头打破，以便进入通常附着的木材屋顶护套，用于垂直通风。板岩和瓷砖比木材或沥青瓦片或金属屋顶重大得多，并且必须设计和构建支撑结构以支撑此重量（死载）。
一些现代屋面马terials look like one of the traditional materials from the ground but are not the same. Examples are the large steel, aluminum, or plastic panels that are colored and formed to the shape of wood shingles, tiles, or slates. These panels interlock and are attached to the roof sheathing.
The type of roofing material, type of roof sheathing, and type of roof supports (rafters or trusses), are important notes for our普雷丝计划对于任何结构。如果你没有preincidentplan for the structure, assume that the roof is manufactured wood supported by trusses or I-joists and that the roof covering will be difficult to cut or break. In any case, vertical ventilation of most pitched roofs today is most safely done from an aerial ladder or platform, rather than from the roof or a roof ladder. Horizontal ventilation of attics and truss lofts by opening both gable ends is also an option.
Search the Internet for “metal roofing materials” and “plastic roofing materials” for manufacturer information on a variety of these products.
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格雷戈里哈维尔is a member of the Town of Burlington (WI)Fire Department; retired deputy chief andtraining officer; and a 30-year veteran of thefire service。他是威斯康星州认证的fire instructorII, fire officer II, and fire inspector; an adjunct讲师在fire serviceprograms at GatewayTechnical大学;和安全Scherrer Construction Co.，Inc.Avel董事哈德尔担任圣诺伯特学院学士学位;拥有30多年的设施管理和建筑施工经验;并在FDIC上提出了课程。
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