A simulation model for assessing building firesafety

This paper presents a computer simulation technique for analyzing emergency evacuation and building firesafety. The systematic, objective procedure includes mathematical modeling, graph theory and simulation to represent and analyze the building layout.     

An agent-based model of building occupant behavior during load shedding

Load shedding enjoys increasing popularity as a way to reduce power consumption in buildings during hours of peak demand on the electricity grid. This practice has well known cost saving and reliability benefits for the grid, and the contracts utilities sign with their “interruptible” customers often pass on substantial electricity cost savings to participants. Less well-studied are the impacts of load shedding on building occupants, hence this study investigates those impacts on occupant comfort and adaptive behaviors. It documents experience in two office buildings located near Philadelphia (USA) that vary in terms of controllability and the set of adaptive actions available to occupants. An agent-based model (ABM) framework generalizes the case-study insights in a “what-if” format to support operational decision making by building managers and tenants. The framework, implemented in EnergyPlus and NetLogo, simulates occupants that have heterogeneous thermal and lighting preferences. The simulated occupants pursue local adaptive actions such as adjusting clothing or using portable fans when central building controls are not responsive, and experience organizational constraints, including a corporate dress code and miscommunication with building managers. The model predicts occupant decisions to act fairly well but has limited ability to predict which specific adaptive actions occupants will select.     

A generalised stochastic model for the simulation of occupant presence

This paper describes an algorithm for the simulation of occupant presence, to be later used as an input for future occupant behaviour models within building simulation tools. By considering occupant presence as an inhomogeneous Markov chain interrupted by occasional periods of long absence, the model generates a time series of the state of presence (absent or present) of each occupant of a zone, for each zone of any number of buildings. Tested on occupancy data from private offices, the model has proven its capacity to realistically reproduce key properties of occupant presence such as times of arrival and departure, periods of intermediate absence and presence as well as periods of long absence from the zone. This model (due to related metabolic heat gains), and associated behavioural models which use occupants’ presence as an input, have direct consequences for building energy consumption.     

A comparison of occupant comfort and satisfaction between a green building and a conventional building

It has been argued that “green” buildings have a better indoor environmental quality (as measured by the comfort perceptions of occupants) than conventional buildings and that this translates into a more satisfying workplace for the building's occupants and, in turn, a more productive workforce. To test this we measured the comfort and satisfaction perceptions of the occupants of a green university building and two conventional university buildings with a questionnaire that asked occupants to rate their workplace environment in terms of aesthetics, serenity, lighting, acoustics, ventilation, temperature, humidity, and overall satisfaction. The university buildings at the centre of the study are located in Albury-Wodonga, in inland southeast Australia. The green building, which is naturally ventilated, is constructed from rammed earth and recycled materials. The conventional buildings have heating, ventilating, and air-conditioning (HVAC) systems and are of brick veneer construction. We found no evidence to believe that green buildings are more comfortable. Indeed, the only difference between the buildings was that occupants of the green building were more likely to perceive their work environment as warm, and occupants who felt warm were more likely to describe their work environment as poor. However, the hydronic cooling system of this building was malfunctioning at the time of the study and hence this result cannot be generalised as a difference between green buildings and conventional HVAC buildings. All other aspects of comfort, including aesthetics, serenity, lighting, ventilation, acoustics, and humidity, were not perceived differently by the occupants of the two types of building.     

A very simple method for assessing tall building safety in major fires

The collapse of tall buildings in a densely populated urban setting is a scenario too terrible to contemplate. Buildings are routinely designed to resist this limit state under the extreme loading conditions of high winds and earthquakes etc. However the potential of multiple floor fires to cause such a disaster remains unrecognised in the profession as no current building codes require the consideration of this type of extreme loading. Previous work by the author and his students has demonstrated that the collapse of tall buildings in multiple floor fires is a distinct possibility as the mechanisms that can cause this are easily reproduced using a non-linear finite element analysis programme. This work has been extended by the author and his students to develop a simple analytical method for systematically assessing the collapse of exterior columns of tall buildings for any given fire scenarios. This paper considerably simplifies the method developed previously to the extent that the limit state of collapse under multiple floor fires can be checked even without the need to consider any particular “design” fire and with calculations that can be performed in minutes. This is based on the assumption that in major fires that affect multiple floors, it is quite likely that a number of floors will reach a state of deflection and reduced stiffness that the main load carrying mechanism will be that of catenary action leading to destabilising pull-in forces to be exerted on exterior columns. The paper will outline all the steps that must be carried out to check if the remaining structure (columns, floors, connections etc.) will remain stable under the action of the pull-in forces. It will also provide theoretical justification and discussion for all the steps and assumptions made in the assessment. Furthermore the method will be applied to a number of examples, including that of the WTC towers to check if those buildings were safe under major fires involving multiple floors.     

Potential for energy saving in building transition spaces

This paper reports on an analytical investigation into the energy saving potential associated with modified comfort limits in transitional spaces in buildings. Such spaces may not require the same high level and close environmental control of more fully occupied spaces and thus a wider variation in conditions and interpretation of thermal comfort may be permitted. Estimations are made of energy saving potential based upon typical floor area proportions utilised for transition spaces of various types in office/commercial buildings. The data are combined with suggested norms for comfort expectation that have wider temperature limits than for normally occupied office zones. The method has been applied to a series of building types situated in the climate of the East Pennines area of the UK using a thermal analysis tool. The results show that useful energy savings (particularly for heating) are possible by allowing for a modest (and realistic) relaxation of prescribed comfort standards in transition spaces. Further work is now required to confirm the limits and assess energy saving in practice.     

抽样清点法在公共场所人员密度调查中的应用

介绍抽样清点方法,应用抽样清点法对成都西单商场的人员密度进行调查,将调查结果与采用其他调查方法进行人员密度调查的结果对比,分析抽样清点法在人员密度调查中的实用性和使用场所,为开展公共场所人员密度等基础数据的调查研究提供调查方法的指导和参考.     

人员密度设定对地下商业空间空调设计的影响

人员密度设定对地下商业空间空调负荷计算、空调系统设计有着重要的影响,以济南某地下商业空间为例,定量描述了上述影响,提出了人员密度的取值思路及相关参考数据,给出了在不同人员密度下一次回风定风量系统冬、夏季的处理极限,对比了冬、夏季风量,结果显示,等送风温差下,冬季风量较夏季风量大.     

Relationships between occupant personality and the sick building syndrome explored

Increasing evidence shows that certain personality traits, such as negative affectivity (trait NA), are strongly associated with the reporting of symptoms. The role of personality in sick building syndrome (SBS) symptom reporting is therefore explored with the aid of a questionnaire completed by occupants living in apartments with indoor climate problems. A good fit to empirical data was obtained for a path model in which somatization intervenes between a general psychological factor (predominated by trait NA) and SBS. Occupants with "normal" and "aberrant" NA profiles were classified by cluster analysis and further divided according to frequency of symptoms. For occupants with 5 or more SBS symptoms, those with "aberrant" NA profiles have very similar SBS symptom profiles to those with "normal" NA profiles. This indicates that an occupant's trait NA score cannot be used for predicting his or her SBS symptom profile or frequency of SBS symptoms. An unexpected finding was that the occupants with "aberrant" NA profiles also perceived factors in the indoor (air) environment as less adverse than the 5 or more symptom reporting occupants with "normal" NA profile. Pennebaker and Brittingham's competition of external and internal cues model may explain the results for the occupants with "aberrant" NA profiles, however, our empirical data indicate that, unexpectedly, these occupants may not over-report SBS symptoms but rather under-report adverse environmental perceptions.     

Identifying the target spaces for building evacuation

This paper introduces the concept of target spaces in an egress system of a building. Target spaces can be defined as areas that are parts of the egress system and have critical effects on a smooth and effective evacuation. The purpose of identifying target spaces is to evaluate the threats to life safety or properties. If the target spaces can be recognized, the analysis of an egress system becomes easier for the evaluation of a building. A program called “LAYOUT” to help identify target spaces is also developed and explained in this paper.     

Modeling ventilation rates in bedrooms based on building characteristics and occupant behavior

Air change rate (ACR) data obtained from the bedrooms of 500 Danish children and presented in an earlier paper were analyzed in more detail. Questionnaires distributed to the families, home inspections and interviews with the parents provided information about a broad range of residential characteristics and occupant behavior. These were tested in several linear regression models to identify the degree of effect each selected independent variable has on the total ACR. The measured ACRs are summarized by some of the most significant variables such as room volume (higher ACR in smaller rooms), number of people sleeping in the bedroom (higher ACR with more people), average window and door opening habits (higher ACR with more opening), sharing the bedroom with other family members (higher ACR in shared rooms), location of the measured room (higher ACR above ground floor), year of construction (lowest ACR in buildings from early 1970s), observed condensation on the bedroom window (higher ACR at less condensation), etc. The best-fitting model explained 46% of the variability in the air change rates. Variables related to occupant behavior were stronger predictors of ventilation rate (model R² = 0.30) than those related to building characteristics (model R² = 0.09). Although not perfectly accurate on a room-to-room basis, our best-fitting model may be useful when a rough estimate of the average air change rate for larger study populations is required in future indoor air quality models.     

Response-relapse patterns of building occupant electricity consumption following exposure to personal, contextualized and occupant peer network utilization data

Behavior can account for significant differences in building energy use. Monitoring and reporting of building energy use may induce occupants to conserve energy. The goal of this study was to assess the behavioral impact of providing building occupants with personal electricity utilization data contextualized with different social frames of reference. We installed monitoring equipment on the electrical meters for 83 rooms of a six-floor residential dormitory building and formulated three study groups and a control group from the building occupants. One study group was provided with their own electricity use, a second group was provided their own electricity use contextualized with average building occupant utilization, and a third group was provided with their own electricity use contextualized with both average occupant utilization and the electricity use of their peer network in the building. The only group that significantly reduced their electricity use when compared to the control group was the study group that could view peer network utilization. All three study groups exhibited response-relapse patterns after viewing their electricity consumption raising important questions about the sustainability of energy conservation and monitoring efforts.     

A comprehensive model for streamlining low-energy building design

Building designers are often limited in their ability to reduce the environmental impact of buildings, due to a lack of information on the environmental performance of building components as well as inconsistencies in the way in which this information is derived. Whilst numerous tools exist to help facilitate the low-energy building design process, these typically require large investments of time and money that are often beyond those available within any particular project. This paper describes an approach for streamlining the design process to reduce building life cycle energy consumption. Building assemblies are ranked based on an assessment of the life cycle energy requirements associated with their use within a building. This facilitates early stage assessment, negating the need for a resolved design before the relative energy requirements of alternate design solutions are known. Previous work assessed the initial and recurring embodied energy as well as the operational energy requirements for heating and cooling associated with the use of a range of building assemblies, using a simplified house model. This paper presents a sensitivity analysis of variations to the floor area, shape and orientation of this model, to test the reliability and applicability of the ranking approach across a broad range of circumstances. It was found that these variations did not influence the ranked order of the assemblies in terms of their life cycle energy requirements. Thus, the ranking of assemblies appears to provide an appropriate approach for streamlining the selection of construction elements during the building design process.     

Relationship between quality of building maintenance management services for indoor environmental quality and occupant satisfaction

Two surveys were carried out to investigate the correlation between building maintenance management services for indoor environmental quality (IEQ) and occupant satisfaction. Each maintenance management organization manager was surveyed using the Evaluation Index of Maintenance Management Service Quality, created by Akira Takakusagi. Seven office buildings in Seoul, Korea were investigated in the first survey, and two buildings from the first survey were selected for analysis in the second survey. One is a building with good maintenance management services but low occupant satisfaction, and the other is an office building with low maintenance management services but high occupant satisfaction.     

Energy in context: A multicriteria model for building design

A model is proposed for the representation and comparison of design alternatives which puts energy efficiency in a context of performances in other criteria. The model utilizes notions of decision and performance spaces and multicriteria Pareto optimization. A simple example is described.     

浅析建筑中的女性空间

通过对比研究女性空间在中国传统建筑和当代建筑中的存在方式,发现传统建筑中对女性空间的过度限定与当代建筑中追求的匀质空间都给女性生活带来极大的不便,并指出适度关注性别差异的必要性,呼吁设计人性化的女性空间。     

A general model for the calculation of daylighting in interior spaces

An analytical model and a computer code have been developed which calculate the amount of daylight illumination on a working surface inside an arbitrary room, for overcast as well as for clear sky conditions. The room may have windows as well as skylights, with clear glass, diffusing glass, or glass fitted with thin shading devices (such as sheer curtains or shades), as well as overhangs. The shape of the room is not limited to simple, rectangular enclosures, allowing the treatment of L-shaped rooms, A-frame buildings, etc.The illumination generally consists of three parts: direct sky illumination, illumination from external reflectors, and illumination from internal reflectors. First, the luminances emanating from surrounding obstructions are determined. Next, illumination traveling through the windows directly to inside walls and working surface is calculated. Finally, interreflection inside the room is taken into account to establish the luminance distributions of inside walls. After determination of all inside and outside luminances, it is a simple matter to calculate illumination and daylight factor for the working surface.     

Evaluation of ventilation code requirements for building crawl spaces

Building ventilation code requirements for crawl spaces were reviewed from 1937 to today and though remain largely unchanged, provide designers and builders flexibility in moisture control methods. This study evaluates the current building ventilation code requirements for at-grade and below grade crawl space using computational fluid dynamic (CFD) software with experiment inputs. The research first tested the soil moisture evaporation rate from two monitored crawl spaces in Colorado, US, which produces an average moisture load of 13.75 grains/(ft²·h) (9.6g/(m²·h)) and a maximum load of 42.7 grains/(ft²·h) (29.8g/(m²·h)). The soil moisture evaporation rates identified align well in magnitude with those recorded in the literature, supporting the estimation method used. The experiment reveals that plastic ground cover can effectively reduce the moisture load from the soil by an average of 93%. The study then developed a CFD model of the monitored crawl space to assess the necessity and effectiveness of various ventilation code requirements. The space effective leakage area to the exterior was determined through field pressurization testing and CFD analysis to be approximately 0.26in.²/ft² of floor area. The CFD predictions, validated with the measured data, verify that the building code requirements for at-grade crawl spaces appear sufficient, but have limitations for below grade crawl spaces. Sealed crawl spaces perform better in humid climates, supporting previous research, and mechanical ventilation is justified for below grade crawl spaces only. The paper provides suggestions for the revisions to the current building code to recognize below grade underfloor spaces.