Isabelina Nahmens

Effects of Lean Construction on Sustainability of Modular Homebuilding

Constructionactivitiesandthebuiltenvironmenthaveanenormouseffectontheenvironment,humanhealth,andtheoveralleconomy. Sustainable homebuilding in all three dimensions of economic, environmental, and social effects is attainable through practical innovations and technologies.However,thegreatestbarriertothewidespreadapplicationofsustainablehomebuildingisthehigherinitialcostslargelyattributable to the learning curve of workers building with these practical innovations and technologies, and the added cost resulting from ill-defined con- structionprocesses.Toaddressthesechallengesandreachtheidealofsustainableconstruction,thispaperproposestheuseofleanconstructionas a viable and effective strategy, in particular the lean tool kaizen. This paper uses several case studies to showcase the effect of lean on the triple bottomlineofsustainabilityinmodularhomebuilding.Eachcasestudyhighlightsonedimensionofsustainability.Leanconstructionresultedina significant environmental effect by reducing material waste by 64%, a significant social effect by reducing or eliminating key safety hazards of excessive force, poorposture, andstruck-by, and a significant economiceffect byreducing productionhours by31%.Findings from this research willcontributetoabetterunderstandingoftheeffectofleanonhomebuilding sustainabilityand willpromotelean and safebuilding techniquesin modular homebuilding. DOI: 10.1061/(ASCE)AE.1943-5568.0000054.

Is Customization Fruitful in Industrialized Homebuilding Industry

The level of customization currently being built by U.S. industrialized homebuilders, including modular and manufactured homes producers, is characterized and the impacts of customization on plant operational performance, and employee and customer satisfaction are examined. To assess the current state of the industry, including the level of customization offered and operational performance, a large-scale survey of industrialized housing producers was conducted. Results revealed that in general, the operational performance of the surveyed homebuilders deteriorates with an increase in home customization. Producers that offer more customization tend to be less efficient in their use of manufacturing space and less efficient with their labor. Results also show that a higher level of customization leads to higher employee satisfaction (lower labor turnover) and leads to lower customer satisfaction. However, those producers that had active quality programs (e.g., continuous improvement) had higher customer sati...

The impact of product choice on lean homebuilding

Purpose – The purpose of this paper is to better define the relationships between product variety and lean production in enabling mass customization in industrialized homebuilding.Design/methodology/approach – This study includes a case study analysis of two housing plants that instituted lean production systems. For each company, the case study documented the companys background, the product choice offered, the lean implementation approach used, the results obtained, and the effect of product choice on the lean implementation. Using these case study findings, common trends were identified and used to develop guidelines for an effective mass customization strategy for industrialized homebuilders. This paper summarizes the extensive findings for one of the two plants and provides the recommended guidelines developed from common trends identified at both plants.Findings – Case study findings indicated that product choice does not necessarily make the implementation of lean concepts more difficult. In fact,...

Use of Safety and Lean Integrated Kaizen to Improve Performance in Modular Homebuilding

The two biggest challenges in the construction industry, low productivity and high injury rates, may be addressed simultaneously through the combination of lean production strategies and traditional safety-analysis tools. This case study used Safety and Lean Integrated Kaizen (SLIK) in a modular housing manufacturing facility by applying one lean production tool, kaizen, and a safety-analysis tool, job safety analysis (JSA). The research team used SLIK with the base-framing crew, and the method consisted of analyzing the current process, determining and implementing process improvements, and analyzing the improved process. The changes resulted in a 16% increase in value-added activities and increased the framing crew’s overall output by 55%. By making quick, low-cost changes that were intended to improve productivity to the station layout and work design, safety and ergonomic hazards, including reduced trip hazards, pinch points, and back strain, were also reduced or eliminated. These results support the ...

Making safety an integral part of 5S in healthcare

BACKGROUND Healthcare faces major challenges with provider safety and rising costs, and many organizations are using Lean to instigate change. One Lean tool, 5S, is becoming popular for improving efficiency of physical work environments, and it can also improve safety. OBJECTIVE This paper demonstrates that safety is an integral part of 5S by examining five specific 5S events in acute care facilities. We provide two arguments for how safety is linked to 5S:1. Safety is affected by 5S events, regardless of whether safety is a specific goal and 2. Safety can and should permeate all five Ss as part of a comprehensive plan for system improvement. METHODS Reports of 5S events from five departments in one health system were used to evaluate how changes made at each step of the 5S impacted safety. RESULTS Safety was affected positively in each step of the 5S through initial safety goals and side effects of other changes. CONCLUSIONS The case studies show that 5S can be a mechanism for improving safety. Practitioners may reap additional safety benefits by incorporating safety into 5S events through a safety analysis before the 5S, safety goals and considerations during the 5S, and follow-up safety analysis.

Lean Homebuilding: Lessons Learned from a Precast Concrete Panelizer

This paper serves as a resource to prefabricated construction managers who are attempting to implement lean thinking to improve their production operations by eliminating waste. Lean is both a general way of thinking and a specific production management approach that emphasizes using less of everything to satisfy the customer by delivering the highest quality at the lowest cost in the shortest time. While providing an overview of lean principles, this paper focuses on two fundamental lean concepts, standardization and continuous flow. To develop these concepts, this paper uses a case-study approach to describe the experiences of a large homebuilder confronted by rising production costs as they migrate wall-building operations from the construction site into a factory. Lean production principles are successfully applied, yielding a 47% increase in productivity and a 25% reduction in lead time. This study also found employee involvement and the supplier relationship as key factors for successful lean implem...

Improving healthcare warehouse operations through 5S

Typically, Lean strategies in healthcare aim at improving patient throughput, reducing medication errors, redesigning work flow, improving patient safety, and reducing cycle time. Documented studies to improve healthcares warehouse operations are not common in the literature. Managing types of medical supplies has always been a priority due to demand uncertainties and the risk of shortages that would profoundly affect patient safety. This study showcases two implementation approaches of the Lean tool 5S (Hybrid and Traditional) conducted in three different hospitals’ central warehouses at Ochsner Health System. These warehouses store similar medical products with over 1,000 types of supplies (e.g., syringes, gloves, primary IV) that supply different departments within hospitals and clinics. The objective was to compare the impact of implementing Hybrid 5S (integrated with inventory management techniques and process improvement tools) with Traditional 5S to improve healthcare warehouse operations. Both approaches resulted in increased inventory turnover (30% increase from Hybrid 5S and 4.0% and 43% increase from the two Traditional 5S). The Hybrid 5S approach had additional improvements including 15.7% space saved and the least non-conformities to the 5S ideals. Hence, by incorporating industrial engineering techniques such as inventory management, results from Lean tools can be enhanced.

5S impact on safety climate of manufacturing workers

Purpose – 5S is a commonly used Lean tool that focusses on creating an organized work environment, but the effects of 5S on safety climate are not as well studied. The purpose of this paper is to determine the impact of a 5S event on safety climate. Design/methodology/approach – This pre-test post-test study examines the effect of implementing 5S on safety climate of the packaging area of a manufacturing plant. Two groups of employees (case and control groups) completed a safety climate questionnaire (Safety Climate Assessment Toolkit) prior to the 5S event, one month after, and two months after. Findings – Total safety climate significantly improved for the case group but remained unchanged for the control group over the study period. Specifically, management commitment and involvement dimensions of safety climate improved for the case group. Practical implications – These results show that two important aspects of safety climate (management commitment and involvement) can be significantly, positively in...

Volatility Forecast of Construction Cost Index Using General Autoregressive Conditional Heteroskedastic Method

AbstractThe Engineering News-Record (ENR) publishes the Construction Cost Index (CCI) monthly, which is a composite index of 20-city average price of construction activities in the United States. Cost estimators use this index frequently to estimate the cost of construction projects. The CCI forecast provides contractors with more accurate bids. It also helps owners with their projects’ budgeting. Previous studies have forecasted this index via multivariate and univariate techniques. Homogeneity of variance is assumed on these techniques, however the CCI shows periods of substantial volatility. So far the standard tools used to address volatility on time series have been the autoregressive conditional heteroskedasticity (ARCH) and generalized autoregressive conditional heteroskedasticity (GARCH) models. In this study, a seasonal historical data set of ENR Construction Cost Index is analyzed in order to extract and forecast volatilities of the CCI in the short term. Results of this study show high and pers...

Impact of Low-Income Occupant Behavior on Energy Consumption in Hot-Humid Climates

AbstractWithin the residential sector, the low-income segment accounts for a significant amount of energy consumption. In addition to poor housing conditions in the low-income sector, occupant behavior is one of the most important drivers of energy performance. This paper examines specific cases of behavior in low-income housing in hot-humid climates. Given the scant literature available on this subject, this study uses both quantitative and qualitative approaches to concurrently analyze both (1) subjective perceptions of low-income occupants and (2) real field data. Using principal component analysis, a wide range of behaviors was categorized into nine independent factors. Then, using multiple regression analysis, those factors were ranked in terms of their impact on household energy bills. The results revealed that the top five behavioral factors that have a significant impact on the energy bills of low-income occupants are the following (in order of importance): (1) cooling set point during summer; (2)...