格雷戈里·哈维尔（Gregory Havel）
一个多世纪以来，人们一直提出，在重木材表面上的一层炭是绝缘的，并且会减慢或防止木材进一步燃烧。弗朗西斯·布兰尼根（Francis Brannigan）于1971年和1982年在他（及其其他作者）书籍的最早版本中质疑这一建议。消防服务的建筑建设。然而建筑木材建筑,是否他的vy timber, wood frame, or lightweight wood structural components continue to burn and are destroyed by fire. If there were merits to this proposal, spectacular photos and videos of these fires would not appear as often as they do on televised news broadcasts or on the Internet.
This proposal is again being used by the people who today promote the use of “mass timber” in construction, which includes glulams, “cross laminated timber [CLT],” “nail laminated timber,” and other variations.
The U.S edition of the交叉层压木手册is free to download athttps://www.thinkwood.com/products-and-systems/clt-handbook。它由美国木材委员会，木材产品委员会以及其他组织和政府机构分发。它在第8章“交叉层压木材组件的火力表现”中重申了这一建议。然而，它在第8章的后面部分指出，在CLT结构的测试建筑中的全尺度火室测试中，墙壁和测试室的天花板受到石膏干墙板的保护。
Char可能是一种绝缘材料，但只有将其冷却到环境温度并与从木头产生的火灾中隔离时。由于字符主要是碳（燃料）和灰烬，因此很容易被点燃。如果不是这样，木炭将不会是户外烹饪的流行燃料。
我建议在木材表面上仍在燃烧的炭是绝缘子。相反，它仍然是其点火温度或高于其点火温度的燃料，并且是燃烧过程的一部分。作为木材木材；承载层压柱，横梁和层压墙和地板面板；其他结构成员继续进行chr，更多的承载木材的横截面将被Char取代，Char的强度很小，无论是压缩还是拉伸。最终，足够的木材将被转换为木炭和燃烧气（水蒸气，二氧化碳等），以使结构成员的安全因子将被烧毁，从而使建筑物的那一部分遭受结构崩溃（照片1）。
（1）作者照片。
If a layer of char had the insulating value that is proposed by the advocates of renewable, sustainable, and “green” construction materials and methods, campfires and fireplace fuel sets using logs would self-extinguish after a short time because of the proposed insulating value of the char formed by combustion. Yet, anyone who has ever enjoyed these fires will recognize that these pieces of wood, with large cross-sectional dimensions, will burn until they are completely consumed or unless someone intervenes by applying water or another extinguishing agent to the fuel.
The officials and organizations that develop and revise building and fire codes have accepted, as fact, the proposal that a layer of char on heavy timber acts as an insulator, despite the history of serious fires in buildings of heavy timber construction. To preserve the lives of the future generations of occupants of these new mass timber buildings as well as the lives of future generations of firefighters who will respond to fire alarms in these buildings, today’s fire service must insist that any building of heavy timber or mass timber construction must provide the following:
- A fire-resistive material like gypsum drywall board over the surfaces of any heavy timber or mass timber components exposed in any room or means of egress from any building that uses these structural components and construction methods. This requirement would permit a room contents fire to burn longer without involving combustible structural members.
- 一个工作的自动消防洒水系统符合国家消防协会（NFPA）13的要求，安装洒水系统的标准, rather than NFPA 13R,安装洒水系统的标准in Low-Rise Residential Occupancies。This requirement would allow fire sprinklers to discharge water on a room-and-contents fire to control it until the arrival of firefighters or even to extinguish it before the fire had grown enough to char and involve large-dimension structural members.
- 在许多生命安全系统,redundancy is the key. The presence of gypsum drywall board to protect the structural members from ignition, combined with the presence of an automatic fire sprinkler system to control or extinguish the fire, is a better assurance that the fire will be confined to its room of origin on arrival of firefighters than either alone. There is similar redundancy in the requirement for a backup power supply (batteries or a generator) for fire alarm and smoke detector systems, for fire department connections on automatic fire sprinkler and standpipe systems to supplement the city water supply, for multiple means of egress from every level of a building rather than a single stairway, for portable fire extinguishers in commercial kitchens that are compatible with the extinguishing agent used in the extinguisher systems in the hoods and ducts over the kitchen appliances, and for multiple safety controls and pressure relief valves on heating and power boilers.
These requirements are needed, whether the mass timber building is of low-rise or high-rise construction, as is proposed for New York City, Milwaukee, and Chicago.
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Gregory Havel我是伯灵顿镇（WI）消防局的成员；退休的副局长兼培训官；以及一名40年的消防人员资深人士。他是威斯康星州认证的消防教练II，消防官II和消防检查员；Gateway技术学院消防计划的兼职讲师；and safety director for Scherrer Construction Co., Inc. Havel has a bachelor’s degree from St. Norbert College, has more than 40 years of experience in facilities management and building construction, has a Chief Power Plant Operating Engineer license from the American Society of Power Engineers (ASOPE), and presents classes at FDIC and other venues.
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