Managing measurement risk in building and civil engineering provides detailed guidance on the use of on-screen measurement both from BIM models and from 2D data such as CAD drawings, PDF files and digital photographs.
Part of the professional armoury of the quantity surveyor is the ability to measure and, for well over a century, this ability has largely focused on the preparation of bills of quantities for tendering purposes. Competence in measurement requires skill, attention to detail and the ability to ‘read between the lines’. It also requires a considerable knowledge of construction technology and experience in understanding and applying formal rules of measurement. There is also an ‘art’ to measurement because good measurers not only have the ability to measure what is on the drawings but are also capable of identifying what the designer has yet to commit to paper.
There is some evidence to suggest that the focus on measurement and bills of quantities is in decline, possibly as a result of changing procurement methods and the emergence of BIM. It is also the case that instead of producing bills of quantities for clients, quantity surveyors are preparing bills for contractors where full or partial contractor design is required by the method of procurement. Measurement, however, is not entirely the province of the quantity surveyor and many other participants in the construction process have or need the ability to measure. Estimators, engineers, planning engineers, subcontractors and various site personnel also use measurement in their work and many practitioners have to juggle more than one method of measurement on the same project.
Measurement should not be considered solely in the context of bills of quantities, however, as it has many uses and applications in the day-to-day management of the construction process including the measurement and valuation of variations, post-contract financial control, claims and final accounts. There is also an important link between methods of measurement, conditions of contract and procurement. The link is risk and this is the central theme of an important and novel new book – Managing measurement risk in building and civil engineering published by Wiley-Blackwell, Oxford –which explores measurement risk in the context of NRM1, NRM2, CESMM4, MMHW and POM(I). The measurement risk implications of various methods of procurement and pricing documents are also covered in detail as are the measurement risks associated with JCT, NEC, ICC and FIDIC conditions of contract.
Traditional measurement books tend to focus, quite naturally, on taking off quantities from line drawings, in accordance with a published standard method of measurement, with the aim of producing bills of quantities. This is to overlook, however, the risk implications of the various standard methods of measurement used in the construction industry worldwide. Each standard method has its own rules as to what is measured and what is not, what is included in an item coverage and what is not and where the balance of risk for items such as excavation, earthwork support, temporary works and method-related items lies. It is also to overlook the fact that contractors habitually receive only a ‘design intent’, and not a fully developed design, which creates risk in terms of the final decision making and design input of contractors and specialist contractors.
Managing measurement risk in building and civil engineering provides detailed guidance on these issues and also recognises that many projects feature elements of partial or complete contractor design that requires careful consideration of how the work is to be measured initially and then managed post-contract. Added to such risk issues is the impact of BIM which is being incrementally adopted in the construction industry.
Measurement from BIM models requires new ways of thinking, professional intuition and great attention to detail in order to produce quantities that are accurate, reliable and fully representative of the work required in any given project. BIM models are object based and whilst quantities may be attached to each object (door, window, cladding panel etc.), ancillary items may not be modelled or quantified. A door may be modelled but not the architraves or a concrete slab might have a volume of concrete but no quantity for formwork or rebar. The skill – indeed the ‘art’ – of the quantity surveyor will therefore be focused more on the information that might be missing from a model, and upon what has to be quantified from drawings or from interpreting a designer’s intentions, than on traditional measurement processes. These issues are explored in Managing measurement risk in building and civil engineering.
Quantities generated from BIM models are not calibrated to methods of measurement and, therefore, whilst considerable measurement effort is saved, the BIM quantities still have to be manipulated into recognisable units and descriptions. Care is needed when generating quantities from BIM models as some items, such as off-site disposal, earthwork support and subcontract attendances etc are not shown in models, just as they were not shown on drawings.
Buildsoft Cubit is the ideal companion for busy practitioners who have to work in the modern context of non-standardised measurement and BIM models. Not only is Buildsoft Cubit easy to learn and use, it also possesses the power, flexibility and interactivity to benefit all those who work with 2D digital drawings and BIM models. Quantities can also be extracted from digital photographs provided that they are calibrated to a suitable scale. As well as providing the ability to measure ‘on-screen’ by importing electronic 2D drawings into the measurement ‘Viewport’, Buildsoft Cubit also benefits from a BIM Reader which facilitates quantity extraction from a model which can then be exported into the estimating/quantities worksheet.
Buildsoft Cubit is not SMM library-based so there is no restriction as to the method of measurement used for taking off quantities and builders’ quantities can be used if preferred. Of particular value is the ability of Buildsoft Cubit to create or import templates from previous bills of quantities and to export to Microsoft Excel. Buildsoft Cubit is featured extensively in Managing measurement risk in building and civil engineering which provides guidance on its use and applications as well as worked examples using a variety of methods of measurement and builders’ quantities.
About the author
The author of Managing measurement risk in building and civil engineering is Peter Williams who has extensive practical experience in building and civil engineering. Peter, a former chartered quantity surveyor, chartered builder and principal lecturer at Liverpool John Moores University, is now retired. He continues to undertake consultancy, lecturing and training work for a variety of contractors, subcontractors and clients in the fields of quantity surveying, construction law, health and safety management, delay analysis and claims.
Managing measurement risk in building and civil engineering may be purchased on-line in both hard copy and e-book from:
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http://eu.wiley.com/WileyCDA/WileyTitle/productCd-111856152X.html
