Office Building Occupants Research Articles

The exposure assessment of airborne particulates matter (PM10 & PM2.5) towards building occupants: A case study at KL Sentral, Kuala Lumpur, Malaysia

Airborne particulates have been recognized as a crucial pollutant of indoor air. These pollutants can contribute towards poor indoor air quality (IAQ), which may affect human health in immediate or long term. This study aims to determine the level of IAQ and the effects of particulate towards occupants of office buildings (the office buildings selected for the case study are SSM, KTMB and MRCB at KL Sentral). The objectives of study are (i) to measure the level of airborne particulates that contribute to the IAQ during working hours, (ii) to compare the level of airborne particulates with the existing guidelines and standards of IAQ in Malaysia and other Asian countries and (iii) to assess the symptoms associated with airborne particulates among the building occupants, which were achieved through primary data collection (case study or site survey, structured interview and questionnaire survey) and supported by literature reviews. The results showed that the mass concentration level of airborne particulates within the areas has exceeded the allowable limit of 0.15mg/m3 by IAQ Code of Practice, 2005 of the Department of Safety and Health (DOSH), Malaysia and 0.05mg/m3 by the Department of Environmental (DOE) (outdoor) of 8 hours continuous sampling. Based on the findings, the highest mass concentration values measured is 2.581 mg/m3 at lobby of SSM building which is the highest recorded 17 times higher from the maximum limit recommended by DOSH than the others. This is due to the nearby construction works and the high numbers of particulates are generated from various types of vehicles for transportation surrounding KL Sentral. Therefore, the development of Malaysian Ambient Air Quality Guidelines on PM2.5 as one of the crucial parameters is highly recommended.

Method for Cost-Benefit Analysis of Improved Indoor Climate Conditions and Reduced Energy Consumption in Office Buildings

Indoor climate affects health and productivity of the occupants in office buildings, yet in many buildings of this type indoor climate conditions are not well-controlled due to insufficient heating or cooling capacity, high swings of external or internal heat loads, improper control or operation of heating, ventilation and air conditioning (HVAC) equipment, etc. However, maintenance of good indoor environmental conditions in buildings requires increased investments and possible higher energy consumption. This paper focuses on the relation between investment costs for retrofitting HVAC equipment as well as decreased energy use and improved performance of occupants in office buildings. The cost-benefit analysis implementation algorithm is presented in this paper, including energy survey of the building, estimation of occupants dissatisfied by key indoor climate indicators using questionnaire survey and measurements. Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) analysis is used in the proposed method for data processing. A case study of an office building is presented in order to introduce an application example of the proposed method. Results of the study verify the applicability of the proposed algorithm and TOPSIS analysis as a practical tool for office building surveys in order to maximize productivity by means of cost efficient technical building retrofitting solutions.

Modeling thermal comfort holistically: Bayesian estimation of thermal sensation, acceptability, and preference distributions for office building occupants

The three concepts of thermal sensation, acceptability, and preference each contribute to a holistic understanding of a building occupant's thermal comfort and how it can be effectively predicted. Nevertheless, there is currently no integrated framework for evaluating sensation, acceptability, and preference together as part of thermal comfort assessment in the built environment. Indeed, the only relation given between these variables in existing comfort guidelines - the Predicted Mean Vote – Predicted Percentage Dissatisfied (PMV–PPD) curve – rests on the tenuous assumption that occupants only find sensations at or near “Neutral” to be acceptable.This paper uses occupant response data from both the laboratory and field settings to develop an integrated approach for assessing office occupant thermal comfort through the multiple lenses of thermal sensation, acceptability, and preference. Specifically, probability distributions are developed for each of these comfort variables using Bayesian probit analysis. Given these distributions, we present revised PMV–PPD curves for field offices, and construct a new set of curves that represent the relationship between PMV and direct thermal acceptability and preference ratings. The probit analysis reveals that PMV is a significant predictor of thermal sensation distribution in the field; suggests that thermal acceptability and preference responses are subject to seasonal influences; and shows differences in thermal sensation, acceptability, and preference distributions for occupants in Air-Conditioned and Naturally Ventilated buildings. The usefulness of the developed distributions to practical thermal comfort assessments is discussed, as is the potential for these distributions to be updated in the future as more data are collected.

User perspectives on outdoor noise in open-plan offices with operable windows

Recent research suggests that buildings with operable windows in general, and mixed-mode (MM) buildings in particular, can provide improved thermal comfort and control opportunities for users. However, there have been concerns about outdoor noise sources such as traffic or construction noise when windows are opened. Concerns like these may hinder the installation of operable windows in buildings. This article examines 23,000 office building occupants’ perspectives on noise from both sealed and naturally ventilated/MM buildings. The results suggest that occupants near operable windows are more satisfied than those near sealed windows or those far from either window type. Among occupants dissatisfied with noise, complaints about indoor noise sources (such as people talking to each other) are about 10 times more prevalent than outdoor noise complaints.

Impact of temperature variation on energy consumption and productivity of the occupants in office buildings

Heating and cooling equipment in office buildings is usually controlled according to external air temperature. However, due to sudden outdoor air temperature variations, indoor climate may not always be adjusted to fit into the comfort range. Despite the modern facilities, occupants may be exposed to a temporary thermal discomfort that affects their performance. The aim of this study was to outline the influence of indoor air temperature variation on office work performance and energy consumption. During the experiment in the real office, indoor and outdoor climate parameters as well as energy consumption were observed. Employees were asked to fill questionnaires by indicating their thermal sensation, perception of air quality and humidity. The results of the study showed that indoor climate changes may cause dissatisfaction of participants, which could lead to their lower productivity. The effects of intermittent indoor climate parameters on energy consumption were outlined as well.

Asthma Induced by Exposure to Spray Polyurethane Foam Insulation in a Residential Home

Spray polyurethane foam (SPF) has recently become a popular “green” solution for insulation systems in residential homes and office buildings in the United States because of its high efficiency, low cost, and eligibility for federal energy tax credits in 2011. All SPFs contain isocyanates that are known to cause occupational asthma,1 but the occurrence of asthma in occupants of homes and building in which SPF is used for energy retrofits has not been reported. CASE A 36-year-old man and a 38-year-old woman living in the same household presented to the pulmonary clinic for evaluation of persistent cough and dyspnea upon exertion. They had moved into a home 18 months previously and had SPF installed in the attic. The patients followed the recommended precautions by evacuating the home for 4 hours. On returning, the patients noted a strong noxious odor, and almost immediately they developed cough, dyspnea, dizziness, nausea, headache, and watery eyes. Several attempts were made to abate the odor by venting the attic, keeping the windows open, and eventually removing the SPF, but the symptoms persisted. After 3 months, the family finally vacated the home. Neither patient had significant medical history. Both were nonsmokers and worked in office-based professions with no exposure to occupational hazards. Both had normal physical examinations, normal routine laboratory tests, including complete blood count and metabolic panels, and normal pulmonary function tests. Both patients showed a positive methacholine challenge test with the methacholine concentration that causes a 20% decrease in forced expiratory volume in 1 second (PC20) of 8 mg/mL for the male patient and 1 mg/mL for the female patient (Fig. 1). The SPF used in our patients' home was a two-component SPF system (Sealection® 500; Dimilec USA, LLC, Arlington, TX) that contained polymeric diphenylmethane diisocyanate (MDI) (50% to 60%), 4,4′-MDI (35% to 45%), and 2,4′-MDI (1% to 5%) in side A. Both patients were diagnosed with asthma or reactive airway dysfunction syndrome induced by exposure to isocyanates and were treated with bronchodilators and inhaled steroids.2FIGURE 1: Results of methacholine challenge tests for the two patients. The tests were done 16 months after the initial exposure. A, For the male patient, the PC20 is 8 mg/mL. B, For the female patient, the PC20 is 1 mg/mL. The dashed line indicates a decrease of 20% in forced expiratory volume in 1 second.DISCUSSION Isocyanates are traditionally used in the automotive, aerospace, metal-working, and wood-working industries.3 They are the most common cause of new onset work-related asthma.4 The use of isocyanates in nonoccupational settings has increased recently, primarily because of the popularity of SPF as an insulation material for residential homes. The home occupants may unknowingly be exposed to isocyanates and be at increased risk for adverse health effects. The “curing” rate of SPF, that is, the time for chemicals in the product to react to produce polyurethane foam, is an important determinant for health effects and varies from 7 to 72 hours depending on the type of SPF product, applicator technique, foam thickness, temperature, and humidity. This curing rate will impact the “re-entry time.” Our patients were told to return 4 hours after the application was completed, and thus were likely exposed to high concentrations of MDI. The clear exposure history, symptoms/signs of asthma, and positive methacholine challenge test established the diagnosis of isocyanate-induced asthma. To our knowledge, this report is the first to describe asthma associated with household exposure to isocyanates contained in SPF. The use of SPF in residential homes likely will continue to increase. This new source of exposure potentially puts a large population at risk for adverse health effects. In response to a growing number of complaints about adverse health effects from homeowners and occupants of office buildings, the US Environmental Protection Agency has recently published an action plan to control exposure to MDI for homeowners and “do-it-yourselfers.”5 Clinicians should be vigilant about this novel exposure scenario to isocyanates when managing patients with new-onset or worsening asthma. Wayne Tsuang, MD Yuh-Chin T. Huang, MD, MHS, FCCP Department of Medicine Duke University Medical Center Durham, NC

The evaluation of occupants’ behaviour and preferences in office buildings in Ghana

Over a period of one year, five office buildings in Ghana have been studied and the occupants were interviewed to assess the operation and accessibility of system and system controls at their working environment. In all, 64 occupants were interviewed. The results show that occupants in office buildings have a strong urge to operate windows, even in air-conditioned buildings. Satisfaction in office environment was found to correlate with the flexibility of building systems, system controls and personalisation of workspace. In addition, to increase the efficiency of building systems, occupants need to be trained in the proper use of the facilities available at their workspaces.The results of the evaluation serve to contribute to the process of refinement and improvementin office buildings.

Monitoring and modelling of manually-controlled Venetian blinds in private offices: a pilot study

This study presents results from a window blind usage survey and field study that was conducted in California, USA during a period spanning from the vernal equinox to the winter solstice. A total of 113 office building occupants participated in the survey. Twenty-five occupants participated in the field study. In this study, 83 measurements of physical environmental conditions were cross-linked with participants' window blind controlling preferences. A total of 13 predictive window blind control bivariate and multivariate logistic models were derived. As hypothesised, the probability of a window blind closing event increased as the magnitude of physical environmental and confounding factors increased (p < 0.01). The main predictors were window/background luminance level and vertical solar radiation at the window. The confounding factors included MRT, direct solar penetration and participants' self-reported sensitivity to brightness. The results showed that the models correctly predict between 72–89% of the observed window blind control behaviour. This research extends the knowledge of how and why building occupants manually control window blinds in private offices, and provides results that can be directly implemented in energy simulation programs.

Application of artificial neural networks to predict prevalence of building-related symptoms in office buildings

Artificial neural networks (ANN) were constructed to predict prevalence of building-related symptoms (BRS) of office building occupants. Six indoor air pollutants and four indoor comfort variables were used as input variables to the networks. A symptom metric was used as the measure of BRS prevalence, and employed as the output variable. Pollutant concentration, comfort variable, and occupant symptom data were obtained from the Building Assessment and Survey Evaluation study conducted by the US Environmental Protection Agency, in which all were measured concurrently. Feed-forward networks that employ back-propagation algorithm with momentum term and variable learning rate were used in ANN modeling. Root mean square error and R 2 value of the simple linear regression between observed and predicted output were used as performance measures. Among the constructed networks, the best prediction performance was observed in a one-hidden-layered network with an R 2 value of 0.56 for the test set. All constructed networks except one showed a better performance than the multiple linear regression analysis.

Partnering for sustainability in the workplace

There is nothing very sustainable about many workplaces. Doing something about it can be expensive, but even when large sums have been spent on design and construction, much of the benefit relies on the cooperation of staff. A more sustainable strategy than the capital investment alone, is to make the workplace more sustainable in the way employees operate in it. More specifically, the key to enduring and efficient work practices that minimise resource use and waste while maximising well-being, is the nurturing of partnerships between the building managers and the workers. Kimmet explores this assertion in relation to the social dynamics in the typical office high-rise. The relationship between office building landlords and occupants has traditionally been confined to financial negotiations over rent and services. This almost inevitably combative arrangement which has contributed to the demands for 'quiet enjoyment' of leases and has significantly retarded the development of stakeholder partnerships so central to the sustainable outcomes. Kimmet argues that the creation of an efficient, productive and rewarding high-rise office atmosphere pivots on disclosure of knowledge, ideas and data, and lubricated by trust, transparency and accountable governance. Without the free flow of information, effective feedback loops and education programmes, office workers will remain disconnected from building management.

The Indoor Environmental Index and Its Relationship with Symptoms of Office Building Occupants

An index for indoor environmental quality, the Indoor Environmental Index (IEI), was developed. This study aggregates the Indoor Air Pollution Index, an index found in the literature, and a new index: the Indoor Discomfort Index. The average of these two indices is the IEI, which is calculated using concentrations of eight pollutants and two comfort variables measured in 100 office buildings in the United States. The database used was developed for the U.S. Environmental Protection Agency Building Assessment Survey Evaluation study. A symptom index also is developed to denote persistent occupant symptoms. The IEI and the symptom index are used to investigate the relationship between indoor environmental quality and symptoms. Two simple linear regression models were formulated; these models explain 67 and 79% of the variation in the average symptom index, with the variation of the average IEI depending on the method of averaging used in the construction of the models. In addition, a conceptual explanation is provided for the empirical or regression models formulated. The IEI and the associated models relating indoor environmental quality with the office occupant symptom index may be used as management tools, as illustrated with an example.

Development of New Volatile Organic Compound (VOC) Exposure Metrics and their Relationship to "Sick Building Syndrome" Symptoms

Abstract Occupants of office buildings are exposed to low concentrations of complex mixtures of volatile organic compounds (VOCs) that encompass a number of chemical classes and a broad range of irritancies. “Sick building syndrome” (SBS) is suspected to be related to these exposures. Using data from 22 office areas in 12 California buildings, seven VOC exposure metrics were developed and their ability to predict self-reported SBS irritant symptoms of office workers was tested. The VOC metrics were each evaluated in a multivariate logistic regression analysis model adjusted for other risk factors or confounders. Total VOCs and most of the other metrics were not statistically significant predictors of symptoms in crude or adjusted analyses. Two metrics were developed using principal components (PC) analysis on subsets of the 39 VOCs. The Irritancy/PC metric was the most statistically significant predictor of adjusted irritant symptoms. The irritant potencies of individual compounds, highly correlated nature of indoor VOC mixtures, and probable presence of potent, but unmeasured, VOCs were variously factored into this metric. These results, which for the first time show a link between low level VOC exposures from specific types of indoor sources to SBS symptoms, require confirmation using data sets from other buildings.

Differences in the Evacuation Behaviour of Office and Apartment Building Occupants

An experiment was designed to observe evacuation times and occupant movement in two office buildings during a simulated fire emergency and to compare these results with previous studies of evacuation drills in apartment buildings. The evacuation drills were recorded using videocameras located throughout the buildings. The results were analyzed with respect to occupant behaviour, occupants' time to start to evacuate, occupants' time to reach an outside exit, and the occupants' speed while travelling in the stairways. A comparison of the results from this office buildings study with previous studies involving evacuations of midrise and highrise apartment buildings reveals many interesting differences. The physical organization of the buildings, evacuation strategies, and the occupants' characteristics, behaviour and movement are discussed. The study showed that apartment building occupants delay their evacuation more than office building occupants, either by a long preparation time or because they cannot hear the alarm from their apartments. Travelling speeds are slowest in midrise apartment buildings where the population is more diverse and includes children, elderly people and occupants with limitations. The more structured evacuation plans, the presence of fire wardens and the easier access to fire safety information also contribute to the efficiency of evacuation procedures in office buildings.

Measurement and Impact of Outdoor Air Supplied to Individual Office Building Occupants on Indoor Air Quality

Measurement and Impact of Outdoor Air Supplied to Individual Office Building Occupants on Indoor Air Quality