金丹

摘要：根据《建筑设计防火规范》要求，公共建筑和住宅建筑的楼梯间应该在首层直通室外，考虑立面美观、疏散距离、功能布局等需要，建筑设计中通常把疏散楼梯间置于中间核心筒位置，导致疏散楼梯间在首层无法直通室外，把防烟楼梯间前室与消防电梯前室合并成扩大前室并直通室外就成为目前最常见做法。由于公建扩大前室同时又兼具大堂的功能，面积比较大，层高比较高，可能还配置接待区、销售区、咖啡吧等功能。扩大前室的复杂性带来一个有争议的问题：扩大前室究竟属于防烟区域还是排烟区域，或者说该如何设计扩大前室的防排烟系统，目前正在实行的《建筑防烟排烟系统技术标准》（GB51251-2017）中未有相关的明确的规定。本文通过对火灾发生时的烟气流动特点、扩大前室和前室防火安全性等级比较及扩大前室的不同用途方面进行详细分析，结合各地方上对《建筑防烟排烟系统技术标准》（GB51251-2017）的相关解释，提出几种不同情况下的防烟设计方法供同行分析探讨。

关键词：扩大前室  机械加压送风方式  自然排烟措施   机械排烟措施

Abstract：According to the requirements of "Fire Protection Code for Building Design"，the stairwell of public buildings and residential buildings should be directly outside on the first floor. Considering the needs of facade beauty，evacuation distance，functional layout and other needs，the evacuation stairwell is usually placed in the middle core tube in the architectural design，resulting in the evacuation stairwell can not be directly outside on the first floor. It is now the most common practice to combine the smoke-proof stairwell front room with the fire elevator front room into an enlarged front room with direct access to the outside. As the public building expands the front room at the same time，it also has the function of the lobby，the area is relatively large，the height is relatively high，it may also be configured with reception area，sales area，coffee bar and other functions. The complexity of expanding the front room brings a controversial issue：whether the expanded front room belongs to the smoke control area or the smoke exhaust area，or how to design the smoke control and exhaust system of the expanded front room，there is no relevant clear regulation in the currently implemented "Technical Standard for Building Smoke Control and Exhaust System"（GB51251-2017）. This article through to the gas flow characteristics，when the fire broke out before expanding chamber and the former room fire safety level and expand the front room of different use aspects in detail analysis，combined with local on "building smoke exhaust system technology standard"（GB51251-

本文主要對《建筑防烟排烟系统技术标准》（GB51251-2017）中3.1.2和3.1.3条前室应采用机械加压送风和不满足自然通风情况下，首层扩大前室防排烟设计问题进行讨论，现以某个办公项目的扩大前室的防排烟设计作为本此探讨分析对象。

1、扩大防烟楼梯间前室安全性和使用功能特点分析

1.1安全性

扩大前室是建筑楼梯间前室的一种特殊存在形式。……