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the fog


improving their knowledge. There is no shortage of information, but much is lost in the noise and almost never reaches the practising engineer.


Faced with this overwhelming wave of


facts and assertions, the CIBSE BIM Steering Group realised that the wider industry would benefi t from some aggregation and ordering of information. The group has initiated a website that, by


working with other institutions and groups, aims to evolve into a non-partisan accessible resource. The resulting website – bimtalk. co.uk – now provides the fi rst iteration of this work and will further develop with the input of participants. Anyone interested is encouraged to make a visit and pass on suggestions (using the contact link on the site) for its future development.


CIBSE’s concerns The CIBSE BIM Group is looking at two challenges peculiar to the building services industry. Our fi rst task is to respond to the draft proposals on the government BIM Task Group’s ‘Labs’ website. We have some concerns that the methods, focused on the needs of architectural models, are less well suited to those MEP systems comprising multitudes of data-rich components. For example, the CIBSE Task Group has anxieties that – despite the volumes of data demanded to meet the requirements of Construction Operations Building Information Exchange (COBie) – the ‘Plain Language Questions’ posed at key early decision stages, tell the client too little about what they are buying, and rather more about process and delivery, than they would usually want to know. Similarly, the draft Uniclass 2


classifi cation methodology contains a few correctable schoolboy howlers (as in grouping heater batteries with lead acid ones) but its coding system


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is more deep-seated concern. Its tables are open to interpretation – so that an entity can be coded in several ways when, presumably, the point of such a system is to ensure that everyone arrives at the same answer. Uniclass 2 does not seem to be at this stage yet. It also appears cumbersome (for example, an attempt to classify an underground drainage survey produced a 46-digit code) but, simultaneously, it lacks the granularity to distinguish between functionally similar, but different, entities.


A second concern is the divide between


MEP BIM practices used in design and in contracting. While designers are confi dent with Level 2 BIM tools, MEP contractors and fabricators are often wedded to Level 1 BIM platforms because they amassed vast libraries of geometrically-exact objects in this format long before Level 2 BIM emerged. The problem is that Level 1 BIM does not


support the myriad data required by formats like COBie UK 2012, and Level 2 BIM does not, as yet, offer much product information that is precise enough for use in fabrication and installation. Thus, we see designers preparing data-rich models using ‘generic’ system components in Level 2 format, which MEP contractors convert back to Level 1 to add the exact product details they need.The result is that crucial information gets lost in translation. Something has to give – and the group is


trying to help. One aspect of this work is the development


of standard product data templates which, if adopted, will enable manufacturers to describe their products in an electronic format usable by all at every stage of a BIM process, and which will greatly simplify completion of the COBie data drops. The group is mindful of the Australian


BIM initiative on page 46 and the power of a top-down approach to pan-industry harmonisation. Despite things becoming clearer, there is still much to be done.


The divide


between MEP BIM practices used in design and contracting is a concern


BIM TaskGroup: key


information Visit www.bimtaskgroup.org to fi nd out more on the following areas  Coordinated work stages – give details of the new digital plans of work that, based on series of numbered stages, should be applicable to all disciplines involved in building, as well as infrastructure and civil projects


 Plain language questions – present, in non-technical language, the details a client requires at a particular project stage to inform their business decisions


 Data demand matrix – identifi es the information that is essential to feed the COBie fi le to satisfy the needs of the construction chain, including the client


June 2013 CIBSE Journal 37


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