在电气工程验收中，桥架防火封堵常常是“非常后一道工序”，也非常容易被施工方“差不多就行”。但正是这道看似不起眼的工序，在火灾发生时决定了火势能否被控制在局部区域。

In electrical engineering acceptance, bridge fireproof sealing is often the "last process" and is also the most likely to be "almost done" by the construction party. But it is this seemingly insignificant process that determines whether the fire can be controlled in a localized area when it occurs.

电气火灾的蔓延，往往从封堵不严的孔洞开始。 据统计，火灾事故中电气火灾占比高达50.4%，而事故调查反复指向同一个原因：建筑竖向管井未封堵或封堵不严，火灾顺势蔓延。桥架穿越楼板和防火墙时留下的孔洞，就像烟囱一样，让火焰和有毒烟气在楼层间快速扩散。一道合格的封堵，能将火灾限制在起火楼层；一道马虎的封堵，等于给火势铺好了蔓延通道。

The spread of electrical fires often begins with poorly sealed holes. According to statistics, electrical fires account for 50.4% of fire accidents, and accident investigations repeatedly point to the same reason: the vertical pipe wells in the building are not sealed or not sealed tightly, causing the fire to spread smoothly. The holes left by the bridge passing through the floor slab and firewall are like chimneys, allowing flames and toxic smoke to quickly spread between floors. A qualified seal can limit the fire to the floor where it started; A careless blockage is equivalent to paving the way for the fire to spread.

封堵方案的选择，取决于孔洞位置和电缆密度。 楼板孔洞可采用防火板封堵、无机堵料封堵或防火包封堵等多种方案。以防火板方案为例：先安装镀锌扁钢支架，铺设阻火网，填塞不燃纤维至楼板上沿齐平，再裁切防火板覆盖孔洞四周至少多出25mm，用柔性有机防火堵料密封边缘，非常后用螺丝固定。无机堵料方案则需将耐水型堵料与水按比例混合，孔洞单边小于600mm时可直接支模填塞，48小时后拆模修整表面。

The choice of sealing scheme depends on the location of the holes and the density of the cables. Floor openings can be sealed using various methods such as fireproof boards, inorganic sealing materials, or fireproof bags. Taking the fireproof board scheme as an example: first install galvanized flat steel brackets, lay fireproof nets, fill non combustible fibers until the upper edge of the floor is level, then cut the fireproof board to cover at least 25mm around the holes, seal the edges with flexible organic fireproof blocking materials, and finally fix them with screws. The inorganic blocking material scheme requires mixing water-resistant blocking material with water in proportion. When the hole is less than 600mm on one side, it can be directly filled with a mold. After 48 hours, the mold can be removed and the surface repaired.

电缆穿孔率是选择封堵方式的关键参数。 当穿孔率大于40%时，应适当提高封堵组件的耐火出众，以实际试验结果确定方案。对于穿孔率较小而洞口较大的情况，应先采用钢筋混凝土或防火灰泥进行缩孔处理，再实施封堵。

The cable perforation rate is a key parameter for selecting the sealing method. When the perforation rate is greater than 40%, the fire resistance limit of the sealing component should be appropriately increased, and the plan should be determined based on actual test results. For situations where the perforation rate is small but the opening is large, reinforced concrete or fireproof mortar should be used for shrinkage treatment first, and then sealing should be implemented.

一个容易被忽略的细节是线槽内部的封堵。 规范明确要求，在贯穿孔口处，所有电缆线槽不仅外部要封堵密实，线槽内部同样需要采用遇火膨胀的防火泥或防火密封胶进行封堵。只堵外部不堵内部，火焰会沿着线槽空腔继续蔓延。

An easily overlooked detail is the sealing inside the cable tray. The specification clearly requires that at the penetration hole, all cable trays not only need to be sealed tightly on the outside, but also need to be sealed with fireproof mud or fireproof sealant that expands when exposed to fire inside the cable tray. Only block the outside and not the inside, the flame will continue to spread along the cavity of the cable tray.

防火封堵不是“面子工程”，而是电气系统安全运行的底线保障。在选择封堵方案时，施工方应严格对照GB 50016和GB/T 51410等标准要求，确保每一处穿越孔洞都经得起火灾的考验。

Fireproof sealing is not a "face saving project", but a bottom line guarantee for the safe operation of electrical systems. When selecting the sealing scheme, the construction party should strictly comply with the requirements of standards such as GB 50016 and GB/T 51410 to ensure that every crossing hole can withstand the test of fire.

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