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Buildability

The Legislation

To reduce the number of workers on site and to achieve higher site productivity, the industry has to adopt more labour efficient designs and use of pre-assembled products. A key measure to achieve this is the introduction of regulations under the Building Control Act, which require building designs to have a minimum buildable design score.

The Building Control Act was amended to facilitate the introduction of new regulations for improving the efficiency and standardisation in designs, processes, construction techniques, products and materials. The regulations pertaining to buildable design was first gazetted on 12 December 2000 and the legislation of buildable design was implemented on 1 January 2001. Projects submitted for URA planning permission on or after 1 January 2001 will be affected by the legislation and are required to comply with a minimum Buildable Design Score.

The Buildable Design Score (B-Score) measures the potential impact of a building design on labour usage. It facilitates the adoption of less labour intensive construction methods and promotes greater use of prefabricated, modular and standardised building components. A design with a higher B-score will result in more efficient labour usage in construction and hence higher site labour productivity.

To accelerate the pace of buildable design adoption, BCA has over the years since 2001, raised the minimum B-Score standard. Depending on the date of planning submission, a project with Gross Floor Area (GFA) of 2,000 m2 and above would be subjected to the minimum B-Score requirement as set out in the relevant Code of Practice on Buildable Design/Buildability as shown in Table 1 below.

In addition to requiring designers to deliver more buildable designs upstream, builders must also play their part to adopt more labour-saving construction methods/technologies downstream. As such, with effect from 15 July 2011, builders of building projects with GFA of 5,000 m2 and above have to comply with a minimum Constructability Score (C-Score) which encourages the use of construction technologies, methods and processes to reduce the industry's reliance on foreign workers. The C-Score measures the level of adoption of labour-efficient construction methods and construction processes such as system formwork and climbable scaffolding. Higher C-Scores would translate to savings in manpower cost and shorter construction time.

Similar to B-Scores, over the years since its introduction, the minimum C-Score requirements have also been raised. These requirements are set out in the relevant Code of Practice on Buildability as shown in Table 1.

Table 1

1st submission date for URA planning permission

Minimum Buildable Design Score and Minimum Constructability Score* Standards

From 1 Jan 2001 to 31 Jul 2002 Code of Practice on Buildable Design,
December2000 issue
From 1 Aug 2002 to 31 Dec 2003 Code of Practice on Buildable Design,
June 2002 issue
From 1 Jan 2004 to 31 Aug 2005 Code of Practice on Buildable Design,
January 2004 issue
From 1 Sep 2005 to 31 Dec 2006 Code of Practice on Buildable Design,
September 2005 issue
From 1 Jan 2007 to 31 Jul 2008 Code of Practice on Buildable Design,
September 2005 issue
From 1 Aug 2008 to 14 Jul 2011 Code of Practice on Buildable Design,
September 2005 issue
From 15 Jul 2011 to 31 Aug 2013 Code of Practice on Buildability
April 2011 issue
From 1 Sep 2013 to 31 Oct 2014 Code of Practice on Buildability
2013 Edition
From 1 Nov 2014 to 30 Nov 2015 Code of Practice on Buildability
2014 Edition
From 1 Dec 2015 to 30 Apr 2017 Code of Practice on Buildability
2015 Edition
From 1 May 2017 Code of Practice on Buildability
2017 Edition
*Applicable with effect from 15 July 2011

Besides the minimum buildability standards, the Code of Practice on Buildability (COP) also covers the legislative requirements, submission procedures and method for computing the B-Score and C-Score.


Enhanced Buildability Framework from 1 May 2017

In December 2015, BCA raised the minimum buildability standards and introduced the mandatory adoption of productive technologies such as welded mesh for cast in-situ concrete floor and prefabricated and pre-insulated duct for air-conditioning systems for all developments. As part of the larger drive towards wider adoption of prefabrication technologies along the Design for Manufacturing and Assembly (DfMA) continuum, there is a need to further enhance the buildability legislative framework to raise construction productivity. BCA has hence amended the Building Control (Buildability and Productivity) Regulations.

Under the enhanced buildability framework, the changes are:

(A) Higher minimum level of use of prefabrication systems for developments on sites sold under the Industrial Government Land Sales (IGLS) Programme

(B) Enhanced Buildable Design Appraisal System (BDAS) incorporating more Design for Manufacturing and Assembly (DfMA) technologies

(C) Separate minimum Buildable Design Scores for basement and superstructure works.

For more details on the changes in the Building Control (Buildability and Productivity) Regulations and the new Code of Practice on Buildability, 2017 Edition, please refer to the following:

  1. Building Control (Buildability and Productivity) (Amendment No. 2) Regulations 2017
  2. Circular on ‘Amendments to Building Control (Buildability and Productivity) Regulations 2011 and Revisions to Code of Practice on Buildability to Raise Productivity in the Built Environment Sector” issued on 15th April 2017
  3. Code of Practice on Buildability, 2017 Edition