Engineered Smoke Control System for a Multi Storey Retail Development with High Atrium

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Problem Statement

When a retail podium exceeds 5000m2 in a single fire compartment, an engineered smoke control system (ESCS) must be put in place to enhance the fire safety standards to comply with the prescriptive code requirements stipulated in the Fire Code 2007. The proposed development has four above grade floors and one floor below grade. All five levels form a single compartment and the aggregate floor area exceeds 5000m2.

Challenge

The main challenges are as follows:

1. The size of the smoke reservoir cannot exceed 2600m2 for mechanical ESCS and the length of the reservoir cannot exceed 60m.
2.Smoke control zones from which smoke (in the event of a fire) spills out into the common corridor or atrium void, cannot exceed 1300m2.
3.The bottom of smoke layer must be at least 2.5m from the highest floor level.
4.The maximum extraction of the ESCS system cannot exceed 175kg/s.
5.Adequate replacement air free area (≥ Volume Extraction Rate / 3) must be provided at low level for the ESCS system to be effective.

Solution

Fixed smoke barriers and/or retractable smoke curtains were used to limit smoke control zones and reservoirs to the prescribed dimensions.

A 5MW fire size (as prescribed by the Fire Code 2007) was assumed to determine the extraction rates required to ensure that the bottom of the smoke layer is kept at least  2.5m above finish floor level (AFFL).

The spillage of smoke from under a balcony into the atrium void results in large volumes of smoke production, especially if the height of rise of the smoke is large. In order to mitigate this, the height of rise of the smoke was reduced by introducing full drop and/or part drop smoke curtains around the atrium voids at upper levels. The extraction rate can be optimised introducing part drop channelling smoke curtains to limit the channelling width.

The replacement air to the engineered smoke control system was taken via the automatic swing/sliding glass doors located at the 1st Storey.

Automatic smoke detection (analogue addressable) system was provided to give early activation of all the related smoke control equipment as well as raising early warning alarm for evacuation process.

Results

The proposed Engineered Smoke Control System together with the active fire protection systems and the proper evacuation procedures by the complex staff greatly enhanced the fire safety standards in the proposed retail podium.

Fig. 1: Design Smoke Layer Height

Fig. 2: Smoke Spill into Circulation Space

Fig. 3: Smoke Spill into Atrium Void