Models of whole life costing

In Whole life-cycle costing: Risk and risk responses, authors Abdelhalim Boussabaine and Richard Kirkham set out to describe the development of whole life cost models through the construction process. It has a particular emphasis on risk management, that is to say, managing the risks of potential inaccuracy within the model, and the consequences of those inaccuracies.

The book is set out in three parts. Part one provides a review of whole life costing and its development in the construction sector. It provides an initial introduction of risk management in chapter two, and then considers some appropriate tools for this in chapter five. Inserted between these chapters are a chapter setting out the key decisions in the whole life costing process, and one describing some of the fundamentals of whole life costing analysis. This order is not ideal, and there is something to be said for reviewing chapter two after reading chapter four!

The remaining parts of the book work through the construction process, from design in part two to the construction and occupancy stages in part three. The strength of this approach is that it relates whole life costing modelling to the practical process. Chapter six reviews the various methods available for estimating or predicting service life. While it refers to part of the ISO standard for service life planning, and discusses the factor method of estimating service life, it omits to mention Part 2 of ISO 15686, which describes more accurate and reliable methods of predicting service life. For a book about minimising the uncertainty of whole life costing predictions, this omission is significant.

Part two then takes a useful detour into environmental life cycle analysis before addressing cost planning at design stage and considering some key uncertainties (or risks) affecting the cost model at the design stage. It concludes with a case study of whole life costing for an m&e design. Unfortunately this case study does not take any account of the influence of the system design on its energy consumption and costs. The authors do not refer to CIBSE TM30, which addresses this in detail, although it may have appeared too late for them to consider it.

Part three then moves into the construction and operational phase, and considers the uncertainties which affect whole life costing models at this stage in the process. The book provides useful material for those not familiar with the field. To this reviewer it suffers from not making adequate links to ISO 15686, especially to part three, which is all about how to provide quality assurance for whole life cost models, and how to test them to establish the uncertainties and risks inherent in them. There are also some irritating typographical errors and a lack of key references, especially in the chapter in environmental life cycle analysis.

This review was by Hywel Davies, head of research at CIBSE.