Search results

As corporate real estate is increasingly being recognised as an important cost and production factor, senior management now pays considerable attention to this asset group. These assets are managed, inter alia, by using benchmarks. In addition to monetary benchmarks, building efficiency (e.g. m² of usable floor area per m² of gross external floor area) and capacity benchmarks in particular (e.g. m² of usable floor area per existing workplace) must be highlighted. Previously, specific values and their drivers for the assessment of buildings or portfolios were not available.

This study is based on a survey carried out in Switzerland, involving the collection of floor data (in accordance with DIN 277) of 116 owner‐operated office buildings. In addition, their drivers were ascertained using regression analyses.

The building efficiency may be assessed on the basis of the share of usable floor area or the share of office space in the gross external floor area. The main drivers are the shares of vehicle parking space, areas for residential and recreational purposes and areas for storage, distribution and retail. These drivers must be taken into consideration when assessing the building efficiency. It became apparent that capacity benchmarks are determined primarily by factors such as the space use management strategies, and only to a lesser degree by the building itself.

The study provides space benchmarks and their drivers. The results therefore permit an objective evaluation of office buildings. However, further work transcending the influence of the building itself will be required with regard to the capacity benchmarks.

The purpose of this paper is to review the historic development of the requirements for sub-floor (also known as “basementless space” or “crawl space”) moisture management in the USA, UK and New Zealand (NZ) from 1600s to 1969.

The review of 171 documents, including legislation, research papers, books and magazines, identified three time periods where the focus differed: 1849, removal of impure air; 1850–1929, the use of ground cover and thorough ventilation; and 1930–1969, the development of standards.

Published moisture management guidance has been found from 1683, but until the 1920s, it was based on the provision of “adequate” ventilation and, in the UK, the use of impermeable ground cover. Specific ventilation area calculations have been available from 1898 in the UK, 1922 in the USA and 1924 in NZ. These are based on the area of ventilation per unit floor area, area of ventilation per unit length of perimeter wall, or a combination of both. However, it was not until 1937 in the USA, 1944 in NZ and after the period covered by this paper in the UK, that numerical values were enforced in codes. Vents requirements started at 1 in. of vent per square foot of floor area (0.7 per cent but first published in the USA with a misplaced decimal point as 7 per cent). The average vent area was 0.69 per cent in USA for 19 cases, 0.54 per cent in NZ for 7 cases and 0.13 per cent in UK for 3 cases. The lower UK vent area requirements were probably due to the use of ground covers such as asphalt or concrete in 1854, compared with in 1908 in NZ and in 1947 in USA. The use of roll ground cover (e.g. plastic film) was first promoted in 1949 in USA and 1960 in NZ.

Common themes found in the evolution of sub-floor moisture management include a lack of documented research until the 1940s, a lack of climate or site-based requirements and different paths to code requirements in the three countries. Unlike many building code requirements, a lack of sub-floor moisture management seldom leads to catastrophic failure and consequent political pressure for immediate change. From the first published use of performance-based “adequate” ventilation to the first numerical or “deemed to satisfy” solutions, it took 240 years. The lessons from this process may provide guidance on improving modern building codes.

This is the first time such an evaluation has been undertaken for the three countries.

In North America, occupant groups and tenants have traditionally used usable area, as defined by the Building Owners and Managers Association, to state their requirements for the amount of floor area they will need in office buildings. However, occupant groups and tenants may encounter planning difficulties prior to move‐in, and thus not “fit” into their newly acquired spaces. Identifies and reviews two methods used in North America, the quick estimation method and the computer‐aided design/facility management method, to determine the amount of occupiable area (the amount of floor area that can be effectively used to lay out furniture and equipment). Explains how each method can be used to ascertain the amount of floor area actually required to eliminate the “squeeze” caused, for example, by the building geometry and grids, and space taken up by columns, projections and obstructions. Discusses the comparative advantages and disadvantages of the two methods.

The purpose of this paper is to show that building stock is currently one of the largest energy consumers. It is thus imperative that buildings are optimally planned, constructed, and used from both the environmental and the economic point of view. Cost models are relevant tools for achieving this objective as they can be used to estimate the occupancy costs in early project phases including energy costs.

In the paper a regression model for predicting the energy consumption and energy costs of office buildings is developed based on the results of a survey conducted in 80 Swiss office properties.

The proposed energy cost model shows good agreement with the observed field data. The mean absolute percentage error resulted in 12 per cent. Validation tests using five properties not used for the model development revealed percentage errors ranging between −17 per cent and 7 per cent. The proposed concept and the presented cost model can be used as a basis for future studies.

The energy consumption and energy cost model can be improved as the database for developing them is further extended (including properties from different owners with different strategies, for example energy contracting, outsourcing, and maintenance strategies).

The objective of the study was to develop and validate a predictive model to facilitate the estimation of occupancy costs in early project phases. A procedure is presented on how quantitative energy consumption and cost models can be developed. Provided that sufficient empirical data are available, this proecdure can be used in further studies as a suitable and practicable concept to advance occupancy cost models.

This paper seeks to examine the potential for simplified market value and non market value based banded approaches to be utilised for residential property tax purposes. The broad aim is to ascertain whether relatively low complexity approaches to establishing a property tax base can perform adequately in comparison to established best practice – in essence whether there is evidence of equifinality (equivalent performance from approaches of substantially different complexity) between simpler and more complex approaches.

The research comprises empirical analysis of a database of property sales and property attribute data drawn from a UK District Council area. Several simplified methods are used to create different tax base scenarios and the outflowing tax incidence is compared with that of using a complex, industry standard market value approach. The methods of comparison are regression and spline regression based models testing for tax inequity, drawn from the literature. The approach here differs from previous work in that it occurs at the actual tax bill level allowing the comparison of value, non‐value and banded approaches.

The findings of the research indicate that simplified approaches to establishing a property tax base can perform in a broadly similar fashion to more complex systems currently practiced in developed economies and therefore evidence of equifinality exists.

The research provides useful tools to property tax policy makers and practitioners in developing and transitional economies in furthering their aspirations of embedding robust property taxes for the furtherance of socio‐economic and political development and the general wellbeing of society and they are of value to property tax policy makers and to academics in the field.

The paper provides evidence of the efficacy of simplified and banded approaches as an option for jurisdictions in developing and transitional economic circumstances or elsewhere in circumstances which mitigate against full scale appraisal of the property tax base to discrete market values. The approaches and techniques pioneered open up opportunities to carry out a range of new comparative analysis of tax base options.

The purpose of this paper is to investigate the effects and relative influence of: surface floor area; number of trowelling machines used in the operation; machine floating ring diameter size; and operative employment mode, on power‐trowelling productivity of concrete surface floors.

To achieve this objective, a sufficiently large volume of productivity data was collected and analyzed using the categorical‐regression method. As a result, the effects and relative influence of the factors investigated on trowelling productivity were determined and quantified.

The findings show significant influence of the factors explored on the trowelling productivity of concrete surface floors, which substantiate the importance of the “economy of scale” concept, and confirm the negative effect of “overcrowding”. On the other hand, contrary to many previous productivity research findings, and anecdotal perceptions of industry practitioners, the results obtained provide little evidence to the positive impact of the subcontracting employment mode on the trowelling operation.

Further research into the influence of other factors which could not be determined by this study, i.e. quantifying the difference in trowelling productivity between the “walk‐behind” and “ride‐on” machine types, and the average change in the operation efficiency as a result of utilizing the 0.60 m “walk‐behind” floating ring diameter size, in comparison with the 0.80, 1.00, and 1.20 m explored ring‐size, is recommended. On the other hand, the results obtained suggest that for a specific surface floor area, there may be an optimum number of trowelling machines, which leads to optimum trowelling productivity. It is, therefore, recommended to determine this number in order to rationalize the use of such devices and optimize the efficiency of the operation.

The findings of this research can provide estimators, planners and construction managers guidance for reasonable estimates, effective planning and efficient operative utilization. The results obtained may be further used to “benchmark” the efficiency of the operation, and “formalize” the specific productivity knowledge acquired.

The outcomes of this study fill a gap in productivity knowledge of primary factors influencing an important surface floor finish technique, which is frequently encountered on concrete construction sites, especially parking structures, storages and industrial facilities.

The purpose of this paper is to review, evaluate and classify the academic research that has been published in facility layout problems (FLPs) and to analyse how researches and practices on FLPs are.

The review is based on 166 papers published from 1953 to 2021 in international peer-reviewed journals. The literature review on FLPs is presented under broader headings of discrete space and continuous space FLPs. The important formulations of FLPs under static and dynamic environments represented in the discrete and continuous space are presented. The articles reported in the literature on various representations of facilities for the continuous space Unequal Area Facility Layout Problems (UA-FLPs) are summarized. Discussed and commented on adaptive and robust approaches for dynamic environment FLPs. Highlighted the application of meta-heuristic solution methods for FLPs of a larger size.

It is found that most of the earlier research adopted the discrete space for the formulation of FLPs. This type of space representation for FLPs mostly assumes an equal area for all facilities. UA-FLPs represented in discrete space yield irregular shape facilities. It is also observed that the recent works consider the UA-FLPs in continuous space. The solution of continuous space UA-FLPs is more accurate and realistic. Some of the recent works on UA-FLPs consider the flexible bay structure (FBS) due to its advantages over the other representations. FBS helps the proper design of aisle structure in the detailed layout plan. Further, the recent articles reported in the literature consider the dynamic environment for both equal and unequal area FLPs to cope with the changing market environment. It is also found that FLPs are Non-deterministic Polynomial-complete problems, and hence, they set the challenges to researchers to develop efficient meta-heuristic methods to solve the bigger size FLPs in a reasonable time.

Due to the extremely large number of papers on FLPs, a few papers may have inadvertently been missed. The facility layout design research domain is extremely vast which covers other areas such as cellular layouts, pick and drop points and aisle structure design. This research review on FLPs did not consider the papers published on cellular layouts, pick and drop points and aisle structure design. Despite the possibility of not being all-inclusive, the authors firmly believe that most of the papers published on FLPs are covered and the general picture presented on various approaches and parameters of FLPs in this paper are precise and trustworthy.

To the best of the authors’ knowledge, this paper reviews and classifies the literature on FLPs for the first time under the broader headings of discrete space and continuous space representations. Many important formulations of FLPs under static and dynamic environments represented in the discrete and continuous space are presented. This paper also provides the observations from the literature review and identifies the prospective future directions.

This paper aims to describe and demonstrate a quantitative areal openness model (AOM) for measuring the openness of floor plans. Creation of the model was motivated by the widely reported but rarely quantified link between openness and adaptability.

The model calculates values for three indicators: openness score (OS), weighted OS (WOS) and openness potential (OP). OS measures the absence of obstructions (walls, chases, columns) that separate areas in a floor plan. WOS measures the number of obstructions while also accounting for the difficulty of removing them. OP measures the potential of a floor plan to become more open. Indicators were calculated for three demolished case study buildings and for three adapted buildings. The case study buildings were selected because openness – or lack thereof – contributed to the owners' decisions to demolish or adapt.

Openness indicators were consistent with the real-world outcomes (adaptation or demolition) of the case study buildings. This encouraging result suggests that the proposed model is a reasonable approach for comparing the openness of floor plans and evaluating them for possible adaptation or demolition.

The AOM is presented as a tool for facility managers to evaluate inventories of existing buildings, designers to compare alternative plan layouts and researchers to measure openness of case studies. It is intended to be sufficiently complex as to produce meaningful results, relatively simple to apply and readily modifiable to suit different situations. The model is the first to calculate floor plan openness within the context of adaptability.

The aim of the study was to develop a practical construction time model for public building projects in Addis Ababa, Ethiopia.

This research work used regression analysis and also exploratory scatter and residual plot techniques. Simple and multiple regressions were used for the investigation of the best fit time model. The analyses were carried out using IBM SPSS statistical software, version 20.

The result revealed that the Bromilow time-cost principle was moderately applicable. However, the cubic regression model (CUB) was found a better time-cost relationship. On the contrary, the study has shown a poor relationship between actual time and gross floor area. Furthermore, multiple linear regression analysis (MLR) consists of three statistically significant variables were found a better fit time model.

The study is limited to only six project scope factors. Further research is recommended to include more building projects of similar type and implications of other factors to improve the reliability of the models.

The developed model was not intended as a replacement for detailed construction scheduling techniques. The resulting model is applicable for front-end predictions of construction duration.

The main parties involved in the building projects should apply the model for benchmarking a precise construction time during the early planning phase.

While most efforts to combat climate change are focussed on energy efficiency and substitution of fossil fuels, growth in the built environment remains largely unquestioned. Given the current climate emergency and increasing scarcity of global resources, it is imperative that we address this “blind spot” by finding ways to support required services with less resource consumption.

There is now long overdue recognition to greenhouse gas emissions “embodied” in the production of building materials and construction, and its importance in reaching targets of net zero carbon by 2050. However, there is a widespread belief that we can continue to “build big”, provided we incorporate energy saving measures and select “low carbon materials” – ignoring the fact that excessive volume and area of buildings may outweigh any carbon savings. This is especially the case with commercial real estate.

As the inception and planning phases of projects offer most potential for reduction in both operational and embodied carbon, we must turn our attention to previously overlooked options such as “build nothing” or “build less”. This involves challenging the root cause of the need, exploring alternative approaches to meet desired outcomes, and maximising the use of existing assets. If new build is required, this should be designed for adaptability, with increased stewardship, so the building stock of the future will be a more valuable and useable resource.

This points to the need for increased understanding and application of the principles of strategic asset management, hitherto largely ignored in sustainability circles, which emphasize a close alignment of assets with the services they support.

Arguably, as the built environment consumes more material resources and energy than any other sector, its future configuration may be critical to the future of people and the planet. In this regard, this paper seeks to break new ground for deeper exploration.