Works Measurement and Methods of Approximate Estimating - Assignment Example

Name of Student Subject Date Coursework 1. Write a brief report outlining how works were measured in the past from the 1850s including the SMM period and how they have changed recently by the introduction of the NRM suit. (Max 750 words count plus illustrations where appropriate). Throughout the planning, design and construction phase of a project, cost estimating is often adopted as a useful tool of cost management. Once the initial budgetary estimates have been established, it is vital to validate the adopted postulates and assumptions through employing certain series of precise techniques of cost estimating. The art of building and constructions can be traced to the ancient ages of the Egyptian, Roman and Greek civilizations. It has however evolved and transformed considerably, becoming more civilised in the manner of portraying and expressing the vision and ideas conceived by the builders. With the industrial revolution, besides the modernising the building practices, it has heralded a vital transformation in the science of value costing as well as cost documentation within the construction world. This transformation led to the realisation of the formalised bill of quantities (BoQs) in the1859. Before that costing was done by ‘measurers’, which quantified and valued the building works after completion and regularly submitted to the client for payment. During bidding or tendering stage, each builder was required to come up with accurate project costs estimates, done by quantifying all the materials and labour required to complete the project. They realized that they were basically duplicating a lot of time and effort quantifying the architects design drawings. Instead they devised a way of employing a professional quantifier to generate the BoQs, forming the basis of preparation of their tenders. During this period, the function of the Boq was basically to form the basis of project costing. With time however, this has evolved, making it to be applicable during both pre- contracting as well as post contracting phases of a project. For instance, in the Great Britain, the concept of consensus of a single price was widely adopted and was driven by client demands. In the 19th century, two major changes occurred. First, in order to set up and generate the fixed price of a project, it was imperative for full details of the proposed project be drawn up clearly, through drawing and design. The next challenge was to determine who between the architect and the engineer or the general contractor is supposed to measure the building works to be constructed. The challenge was solved by the engineer who acknowledged that much of the building works is determined by site conditions and those theoretical quantities of the project needs to be provided based on the bid figures provided by the contractors with the work being re-measured on completion. This simple approach is still being applied in moth earth works projects. For most of the 19th century, in Great Britain, a compromise was reached out, through which the contractors were provided with the BoQ by the architect, which were in some cases measured by an independent body, with the directions that cost of preparation is to be included in each bidding company’s prices. In the UK the Infrastructure Directorate adopted the Stardard method of measurement for construction works, as a replacement of the measurement procedures described above. The advantage of the Standard Method of measurement (SMM) in order to assist in the development of standardisation and consistency of the rates and schedules of bill of quantities thereby providing the following: A systematic structure of bill of quantities and schedules of description and itemisation Standardization of layout, bill of quantities and schedules or rates Standardization of method of measurement estimating and costing of items Subdivision of work on items leading to a consistent, reliable and traceable procedure The objective of SMM is to: Offer such information of the quantities of work thus enabling tenders and estimates are prepared accurately, consistently and efficiently. Offer basis of accurate and updated project planning Provide uniform and consistent data to be adopted in cost databases New Rules of Measurement suite are being adopted to offer a set of measurement guidelines that are understandable to anyone within the construction industry, as well as applicable in all construction spheres (Tas,.2005). Although fundamentally based on Great Britain and thereafter UK practice, the necessity for a coordinated set of guidelines and the underlying concept behind the this new order of cost estimation and cost planning for the capital building projects, has a worldwide applications. This order describes both new building works as well as maintenance works for the purpose of initial as we well as elemental costs during planning and design phase. 2. Describe three methods of approximate estimating Approximate estimating also referred to as order- of-magnitude estimates refers to the estimates prepared during the initial stages of a project lifecycle. There are a number of methods used in the preparation of the approximate estimates as described below. Besides, the use of approximate estimating during the initial project lifecycle, the below methods are in some cases adopted for cost estimates during the detailed design phase of project development lifecycle. Unit estimate This technique of approximate estimating is adopted in the preparation of the preliminary estimates i.e. during the projects conceptual planning phase. This sometimes is referred to as order-of-magnitude type estimate. Ideally during this phase, the total cost estimate is pegged on a single factor. Some of the notable terms and phrases used in unit approximation are ‘per unit factors’ such as cost per cubic metre of concrete, maintenance cost per hour, fuel cost per kilometre, cost per tonne of aggregate etc. Basically the total cost is computed by multiplying the number of units and the unit cost factor of the parameter. For instance if the cost of constructing a unit house is$18,000, and there are 17 housing units to be put up, this means the approximate project estimate is $18,000x17=$306,000. Details of the unit costs may be retrieved from actual costs realised in previous similar projects. It may be necessary to adjust the ‘per unit factor’ lifted from past projects since this varies based on project size, existing market conditions, location and other factors unique to such projects. The accuracy depends on the reliability of the data sourced by the estimator. Factor estimate In this type of approximate estimation, the projected estimate is split into different segments and cost of each segment is computed separation and the final cost calculated by summing up individual segments’ costs (Neil Sinclair 1989). This leads to a more detailed method of cost estimate which gives improved accuracy. This method is favourable in situations where diverse components are involved in cost estimations. For instance by using the illustration of building a multi-storey shopping mall, through unit method total cost may be computed by multiplying the floor space and the cost per square foot of floor space(Wendes, 1976). However, improved estimate can be achieved if the floor space of various rooms such as supermarket, banking hall, java house, and hallway can be computed separately using distinct cost per unit cost associated with each amenity. The required information on materials and equipment can be sourced from the suppliers and manufactures. Cost indexes This method of approximate estimating is adopted for calculating the preliminary project cost estimates by considering past similar projects. In this scenario, cost indices are adopted. Cost indices are basically dimensionless numerical values which show the changes in prices of the both individual and multiple costs items over a period of time. Cost indices update past cost figures to achieve current costs estimates. For a single item, cost indexes are computed as the ratio of current cost of the item (current year), to the cost of the similar item at some point in future (reference year), multiplied by the respective value of the cost index applicable for the reference year. In multiple items, a composite weighted index for the reference through an intricate concept of assigning appropriate weightage factors for the items. References Stapel Silke, Eurostat, Paper submitted to international conference on ICP World Bank, Washington, DC (11-13 March 2002). D. Neil Sinclair, Estimating for Abnormal Conditions, Industrial Press, Inc., New York, New York, 1989 D.W. Avery, “Problems of Locality in Construction Cost Forecasting and Control,” in Building Cost Techniques, edited by P.F. Brandon, E.F.N. Spon Ltd., New York, New York, 1982. H.C. Wendes, The Eight Facets of the Estimating Diamond, Heating/Piping/Air Conditioning, October 1976, pp. 51-56. The Business Roundtable, Modern Management Systems, The Business Roundtable, New York, New York, Report A-6, November 1982. R. Brown, Investigating into the Feasibility of Applying the Pareto Principle to SMM Bills of Quantities and Cost of Planning, Project Report, Loughborough University, UK. Tas, E., Yaman, H., (2005) A Building Cost Estimation Model Based On Cost Significant Work Packages, Engineering Construction and Architectural Management, 12 (3), 251-263. Read More