SPONSOR CPD PROGRAMME Continuing professional development (CPD) is the regular maintenance, improvement and broadening of your knowledge and skills, to maintain professional competence. It is a requirement of CIBSE and other professional bodies. This Journal CPD programme can be used to meet your CPD requirements. Study the module and answer the questions on the final page. Each successfully completed module is equivalent to 1.5 hours of CPD. Modules are also available at www.cibsejournal.com/cpd Offsite prefabrication driven by DfMA This module explores the benefits of the growth in offsite prefabrication resulting from the development of increasingly sophisticated design for manufacture and assembly methods Offsite fabrication is well established in the building services industry, allowing supply chains to produce a high-quality, repeatable product at a competitive cost. The advent of accessible computer modelling and design tools as well as the 4D integration offered by BIM tools have increased the potential to deliver factoryassembled systems and subsystems using methods collectively known as design for manufacture and assembly (DfMA), which minimise onsite construction, as well as potentially offering significant additional benefits. It allows buildings to be constructed more quickly and safely, and in more resource-efficient and costeffective ways.1 Bespoke and mass-produced systems and subassemblies can be created in factory-controlled, weather-protected environments, using dry materials where there is less risk of problems associated with moisture, environmental hazards and dirt. Such a properly managed and controlled factory construction environment will also present considerably fewer health and wellbeing risks, accidents and associated liabilities. As discussed in the recent BSRIA2 report, it is Figure 1: Modular boiler and plate heat exchanger installation, as visualised in modelling environment (Source: Remeha) becoming increasingly common to produce plant subsystems in parts or sections, and then combine them on site to provide the complete plantroom or service space. Once in place, the incoming services and distribution systems are connected to the various plant and equipment within the plantroom. There are potential significant economic opportunities in producing systems off site. The UK Governments recent call3 for evidence (closed July 2019) on how best to adopt and embed a platform approach to design for manufacture and assembly (p-DfMA) indicated that the UK construction sector encompassing contracting, product manufacturing and professional services had a turnover of around 370bn. However, the potential of the construction sector is considered to have been held back by poor productivity growth, which has been significantly lower than the wider economy for example, in manufacturing, which has seen a 50% increase in output per hour worked between 1994 and 2015. Among the many and varied measures of productivity, the potential benefit of offsite production was recently4 highlighted by a report suggesting the productivity of factory staff is 80% relative www.cibsejournal.com November 2019 87 CIBSE Nov19 pp87-90 CPD v4.indd 87 25/10/2019 16:00