Salvatore Ancona
All images courtesy of author
隔离墙的故障是消防员在砌体建筑中必须抗衡的许多问题之一。当涉及到不承担的墙壁或外墙墙时，这些墙壁的突然失败会伤害或杀死下面的毫无戒心的消防员。在所有类型的结构上都存在栏杆墙，但是，当涉及III型（普通）结构的建筑时，可燃的空间空间的存在和Cocklofts中隐藏的火灾可能是栏杆失败的处方。有多少名消防员在制造屋顶时检查栏杆的完整性？司机多久与撞上栏杆或在其上设置空中或桶？这些也可能是导致这种墙壁故障的因素。我们必须不断评估从操作开始到结尾的承重和非负载砌体组件的完整性。
相关的消防员培训
nonload-beari护墙是独立的ng wall which extends upward passed the roof line. (Figure 1). It usually exists on every exposure however older buildings or those built with appropriate scupper drains or significant slope may have the parapet on three sides. (Figure 2). Why do parapets exist? Parapets main function are to protect the edge of roof assemblies from wind uplift forces. Wind blowing against a building produce serious pressures upward which can literally pull the roof off of a structure. The addition of a continuous wall therefore moves the wind up and out. Parapet walls today are built much differently than 80 years ago. When looking at ordinary constructed buildings, we often see a steel I-beam that runs the entire front of the building upon the front wall. The parapet wall is then built on this I-beam and scantily secured via masonry anchors into the wood roof joists within the cockloft. Usually, another steel I-beam girder then runs perpendicular to the other, running front to back. This can support the roof joists and also protect against loads on the front and rear walls. The steel within the cockloft is unprotected and may remain unseen due to layers of ceiling. This can be seen in both single- and multi-story buildings. It should also be noted that the front of such buildings often incorporate decorative masonry unsupported facade walls, which conceal the presence of the structural members.
Failure can occur in a number of ways. First and foremost, when fire rages within the space that includes the steel members, the steel is subject to expansion. When the steel girder expands, even inches, this pushes the I-beam supporting the parapet wall outward, and well, you know the rest. The parapet often falls as a single unit rather than in pieces. This also causes the facade wall to come down as well. The I-beam that is in line with the front wall is also susceptible to expansion from fire and subsequent failure. Because the exposure 2 and 4 walls are often load-bearing walls, when the I-beam supporting the parapet expands it can warp, bend, and twist against the sturdy walls, compromising roof joists, pushing out the facade wall, and letting the parapet wall loose.
Another issue we see is the deterioration of the parapet wall because of the elements. (Figure 3). This is where architects often struggle the most—getting a watertight seal where the parapet meets the roofline. There are many ways they incorporate flashing and canting strips, membranes, and others to seal the roof. Over time, without upkeep, water and the elements weigh heavily on the wall, deteriorating bricks, and mortar. The coping on top of the parapet wall is very important, however over time this may break loose or be taken off for some reason or another, leaving the elements to drain along the wall. This is why it is important to verify parapet wall integrity when on the roof as well as avoid hitting the parapet with your aerial, which can unsuspectingly cause the collapse of a previously deteriorated wall.
相关的消防员培训
PARAPET COLLAPSE:A SERIOUS DANGER FOR FIREFIGHTERS
Construction Concerns: Parapeted Firewalls
从中获得最好的选择是对cockloft进行可观的评估，其中包括栏杆时结构的前部。这将使您能够查看支撑这堵墙的结构成员是否合理。如果除了水平火传播之外还有Cockloft参与，您必须确保将内部的任何钢制成员冷却，否则您将稍后付费。当屋顶消防员到达目的地时，请确保栏杆稳定。如果有损坏或运动的迹象，请将其传递给事件指挥官，并采取行动清除该区域。尊重建筑物前后后部的塌陷区域。如果有立面墙妥协的证据，您可以确定栏杆参与，因为外墙壁经常被绑在栏杆中。
Salvatore Ancona是拿骚县（纽约）消防学院的副首席消防教练；贝尔莫尔（纽约）消防局的前队长兼培训官；以及纽约皇后区的医护人员主管。他有A.S.拿骚社区学院的消防科学学位，并在约翰·杰伊刑事司法学院的紧急服务管理局本科课程中获得。安科纳是the building construction page “The Sons of Brannigan” on Facebook并获得了2019年FDIC国际Honeywell Dupont奖学金的获得者。
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