International Journal of Architecture, Engineering and Construction Vol.1, No. 1, March 2012, pp. 30-36 Factors Affecting Productivity of Pipe Spool Fabrication Seyed Parham Mosayebi 1 , Aminah Robinson Fayek 1,* , Laury Yakemchuk 2 , Scott Waters 2 1 Department of Civil & Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 2W2, Canada 2 Aecon Industrial Western Inc., 53367 Range Road 232, Sherwood Park, Alberta T8A 4V2, Canada Abstract: Pipe spool fabrication is an early stage in industrial construction projects and is crucial for the successful delivery of a project. Pipe spool fabrication is a complex and uncertain process due to the uniqueness of its products. The productivity of the fabrication process and the factors affecting productivity are therefore of great importance to project managers and construction researchers alike. Being able to identify all of the sig- nificant factors affecting productivity is critical to the ability to accurately estimate productivity and ultimately improve the fabrication process. This paper introduces the factors that affect the productivity of the pipe spool fabrication process that are not accounted for in the production unit of spools. In addition, the impact of each factor on productivity is illustrated, and different methods for modeling these factors are proposed. This paper provides a framework for a more comprehensive approach to estimating the productivity using the production unit of spools. Keywords: Diameter inch, factors, pipe spool fabrication, productivity DOI: 10.7492/IJAEC.2012.003 1 INTRODUCTION Pipe spool fabrication falls under the category of in- dustrial construction processes. The term “industrial construction” is used to describe a wide range of facil- ities for basic industries, such as petroleum refineries, petrochemical plants, nuclear power plants, and oil/gas production facilities (Barrie and Paulson 1992). Pipe spools are normally built in a fabrication shop through a series of cutting, fitting, welding, and other processes according to the engineering designs (Song et al. 2006). Final products are either assembled, and form large modules, or are shipped directly to a construction site for installation. At a higher level, the piping process can be divided into four phases: design, pipe spool fabrication, mod- ule assembly, and site installation. Pipe spool fabrica- tion directly affects module assembly and site installa- tion, therefore it is a critical stage not only in a piping project (Hu and Mohamed 2011), but also in an overall industrial construction project. As a result, the pro- ductivity of the spool fabrication shop has always been of great interest to researchers. Fayek and Oduba (2008) introduced many factors that affect the productivity of field pipe rigging and welding processes on an industrial construction project. These factors can be categorized into three groups: at- tributes of the spool, attributes of the crew, and envi- ronmental conditions. In this study, Fayek and Oduba developed a fuzzy expert system to estimate labour productivity, defined as manhours per unit quantity, using, as inputs, the introduced productivity factors. Three models were developed to estimate the produc- tivity of pipe rigging, carbon steel butt welding, and alloy steel butt welding. These models had a numeri- cal accuracy of 38%, 49%, and 41%, respectively, and a linguistic accuracy of 86%, 75%, and 50% respectively. Tommelein (2006) investigated the effects of using standardized spools, both in the fabrication shop and for on-site installation processes. According to her def- inition, a “specific” material refers to a material that is a one of a kind, which means the facility’s design only has one of it. In contrast, a “standard” material refers to materials that are identical and have been used more than once in the facility. She used a simulation model to measure the effect of using standard materials for piping projects. Her model indicated a reduced cycle time in the fabrication of standard materials, in com- parison to specific materials. Sadeghi and Fayek (2008) used a work breakdown *Corresponding Author. Email: aminah.robinson@ualberta.ca 30