Prefab Facades – from Prototype to Product?

A methodological approach to a streamlined design and fabrication process

Overview

Authors

Photo of Lisa Rammig

Lisa Rammig

Eckersley O’Callaghan

lisa@eocengineers.com

Photo of Andrea Zani

Andrea Zani

Project Manager and Engineer

Eckersley O’Callaghan

andrea@eocengineers.com

Photo of Tim Murphy

Tim Murphy

Eckersley O’Callaghan

timmurphy@eocengineers.com


Abstract

Building envelopes are not only an immediately visible part of the building, they have also become a major factor both for cost and performance of the building. Façades significantly affect the environmental performance of a building due to their passive contribution to operational energy demand as well as their embodied carbon linked to each life cycle phase.
Thus, the importance of prefabrication is growing in the building industry as it allows faster construction whilst achieving high quality in a cost-effective manner. Although prefabrication for structural components or entire walls, cores and floorplates are a relatively recent development, it has already been widely used in the manufacturing of building envelopes, particularly in the case of unitized curtain wall systems. Curtain walls consist of prefabricated, interlocking elements spanning from story to story forming the weather tight building envelope that is suspended from the slab-edge and hence wraps the building like a ‘curtain’. Assembly of units under controlled factory conditions allows for higher precision, resulting in improved quality and reduced risk of failure by limiting the on-site labor to a minimum.

One of the major challenges faced by engineers during the early phases of the building design process is to continuously support the architectural team by rapidly developing technically viable and economically feasible solutions which achieve the desired design intent, often for several design options and iterations.

This paper outlines an approach addressing this challenge, attempting to bridge the gap between design, fabrication and installation. New tools are presented that allow designers to iteratively validate concepts based on a pre-engineered system that is optimized for performance and takes fabrication, transport and installation costs as well as maintenance and circularity into account.

Introduction

In the last decades, increasingly strict energy regulations and building standards have led to continuous demand for better performing buildings that are deliverable in increasingly shorter timeframes and within reduced

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Current and emerging façade design technologies: Kit-OF-PARTS

In Europe the curtain wall market is dominated by system providers with specific profiles and various typical details that allow architects to design conventional envelopes that are sized on the

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Tools

The authors have developed a tool kit that allows a design team to pre-engineer the facade based on a variety of factors. The KoP design workflow consists of five engineering

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Sample Library

In addition to the digital collected in generated in form of a sample library. This library contains small scale samples of the typical materials that are part of the KoP

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Performance Testing

Given the complexity of the variety of functions that the building envelope fulfils and the related performance criteria, physical testing in addition to analytic validation is typically required. For this

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Cost model and Circularity

In order to assist the design team in the development of a façade within budget, the KoP design tool incorporates a cost tool into the workflow. The cost tool provides

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Summary

The KoP approach outlined in this paper translates the circular design process typically used for the development of commercial products and efficiencies related to it, to the design of building

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Acknowledgements

The authors would like to thank the team at Loisos + Ubbelohde (L+U) who have developed a shading design tool that integrates with the facade design tools to form a comprehensive envelope Kit of Parts. Particularly Susan Ubbelohde, Brendon Levitt and Stephen Wasilewski.

Rights and Permissions

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