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To determine the probable drainage load for sizing a stack serving a number of domestic washrooms in high‐rise buildings, with various occupant loads served by an appliance and simultaneous use of appliances in a domestic washroom taken into account.

With the reported probable demand patterns of domestic appliances from laboratory testing results, on‐site measurements and survey studies, the probable maximum discharge flow rates from a number of domestic washrooms in a stack are estimated with Monte‐Carlo simulations.

The results demonstrated that the occupant loads and the usage patterns of an appliance had significant effects on the sizing of a drainage stack. It was reported that a reduction of 16 per cent in the design discharge flow rate for a washroom, at an occupant load of 4.2 persons per apartment, could be achieved with no more than one appliance discharging at a time. Influence of the occupant load served by an appliance on the probable maximum drainage demand at the stack was addressed. The results also showed a reduction of the predicted discharge flow rate at the stack serving a number of typical domestic washrooms from −26 to +21 per cent as compared with those predicted by the nominal occupant load in current practice.

The model parameters were determined from surveys for some high‐rise residential buildings in Hong Kong and from some laboratory testing results for typical domestic sanitary appliances. The model therefore may require adaptation for use in other countries.

A useful source of information in determining the stack size serving a number of domestic washrooms for those involved in building design and management related to drainage systems of residential buildings.

This paper proposes mathematical expressions in sizing a drainage stack serving a number of domestic washrooms in high‐rise buildings, where drainage demands are dependent on the building occupant loads at certain discharge patterns of appliances in a domestic washroom.

The aim of this paper is to propose alternative sampling schemes for indoor air quality assessments in which a balance between the sampling time required and number of sampling points chosen is allowed.

CO₂ was used as a reference to evaluate the existing and the proposed sampling schemes for average indoor pollutant concentration regarding the sampling time and sampling point density required and the probable errors induced at certain confidence levels of the measurement.

The results showed that increasing the number of sampling points would significantly reduce the corresponding sampling time required: at the same confidence level, doubling the sampling point density from 250 m² to 500 m² per measurement point would reduce the sampling time required from eight hours to three hours.

The model parameters were determined from surveys for some typical offices in Hong Kong and therefore may require adaptation for use elsewhere.

A useful source of information in determining the number of sampling points chosen and the duration of the measurement needed according to the “acceptable” measurement uncertainty allowed.

Providing flexibility in IAQ assessment, the results would be useful to policymakers for making decisions on resources and manpower management for their respective sampling strategies while taking the uncertainties into account.

The purpose of this paper is to propose a screening test for indoor air quality (IAQ) assessment by auditing only a few “dominant” contributors for preliminary measurements in air‐conditioned offices.

In Hong Kong, up to ten common indoor air pollutants have to be audited in determining the IAQ acceptance for typical air‐conditioned offices. Indeed, parameters could not be uniformly contributed to the assessed “IAQ satisfaction”. The study reviews the past ten‐year assessment experiences in Hong Kong and investigates the “dominant” contributors of unsatisfactory IAQ for screening tests.

When compared with the “full” assessment of all ten listed parameters, a screening test with assessment parameters reduced by half would correctly identify 96 per cent unsatisfactory and 95 per cent satisfactory cases.

The screening test was developed with the reported patterns of the ten common air pollutants from on‐site measurements and survey studies in typical air‐conditioned offices in Hong Kong. Therefore, the test application may require adaptation for use in other countries.

The study shows the usefulness of a regional database in developing a screening strategy for IAQ and so it would be a useful reference for policymakers in evaluating a cost‐justified IAQ assessment protocol.

The paper proposes a simple screening test which can identify the probable unsatisfactory IAQ in offices by assessing only a few “dominant” contributors, with selection of representative assessment parameters based on experiences.

The purpose of this paper is to examine the air pressure variations in an in‐use drainage stack of high‐rise residential buildings with the probable influence of occupant loads.

The air pressure variations in a drainage stack of a typical in‐use high‐rise residential building in Hong Kong were correlated to the number of water closet (WC) flushes of the building. In particular, measured diurnal WC flushing patterns of the residential buildings were used to correlate the diurnal pressure variations measured at 16 m above the stack base in a 115 m high, 150 mm diameter fully vented drainage stack of a typical high‐rise residential building of Hong Kong.

The occurrence of the maximum air pressure in the stack could be correlated with the expected hourly WC flushes of the high‐rise residential buildings with mathematical demonstrations.

There may be high speed transients in the stack (>1 hertz) which was not measured.

The result would be a useful source of reference for the development of control strategies against probable appliance seal loss in high‐rise residential buildings.

This study seeks to investigate the usefulness of occupant acceptance as a preliminary screen measure for offices' indoor air quality (IAQ). An effective alert indication of IAQ problems of a concerned indoor environment would help to promote good IAQ.

The study evaluates the hypothesis that the occupant dissatisfaction with the overall indoor environment provides an indication of IAQ problems. Hence, occupant dissatisfaction would be used as a screening parameter to identify problematic IAQ regarding some IAQ criteria in subsequent IAQ assessments. The hypothesis was tested with a database of regional cross‐sectional measurement in 490 offices within Hong Kong.

The occupants' dissatisfaction with the indoor environmental quality (IEQ) was correlated with the IAQ assessment results of nine IAQ assessment parameters regarding some IAQ criteria for air‐conditioned offices. At certain screening levels of predicted IEQ dissatisfaction, the performance of the proposed screening tool, indicating unsatisfactory office IAQ, was evaluated in terms of the test sensitivity, specificity, predictive values and Yule's Q statistics. The results showed that occupants' response to the indoor environment produced indications of unsatisfactory IAQ regarding the requirement of an “Excellent” office.

The subjective feelings of occupants are capable of identifying marked indoor environmental problems, but cannot identify the “marginal” IAQ problem cases.

The study shows the usefulness of using occupant acceptance to identify the unrecognized IAQ problems for air‐conditioned office environment. Using the identification model developed in the study, all the suspected cases were associated with a high chance of IAQ dissatisfaction and subsequent IAQ assessments were thus recommended.

The paper proposes a new identification method to identify the unrecognized IAQ problems which may indicate unsatisfactory IAQ. Also, the occupants' responses on the indoor environment are quantified.

To determine the domestic flushing water consumption for a building development.

A statistic mathematical model is proposed and the model parameters are sampled with the Monte Carlo sampling technique. The frequency distribution of the parameters for Hong Kong is identified from the survey results of the water closet usage patterns in five typical residential building estates. In particular, the density function of the diurnal variations of occupant load and flushes per occupant, and the cistern volume of the water closets in 597 apartments are used to establish the model.

The flushing water consumption of the residential developments in Hong Kong is determined and compared with the measurement result of typical residential buildings.

The model parameters are not exhaustive and are determined from surveys in Hong Kong, which perhaps limits the model's usefulness elsewhere.

A useful source of reference in determining the domestic flushing water consumption of building developments for those involved in building design and management related to the flushing water systems of residential buildings.

This paper proposes a statistical mathematical model of domestic flushing water consumption and presents a template to determine the required model parameters. The model offers practical help to professionals involved in planning, designing and managing the flushing water facilities for domestic buildings.

It is costly to sample all air pollutants of a general community for continuous indoor air quality (IAQ) assessments. To optimize the resources for IAQ baseline monitoring for general facilities management, this study aims to investigate the feasibility of using a simple IAQ index as a screening parameter of a screening test to identify an asymptomatic air‐conditioned office with probable unsatisfactory IAQ.

The IAQ index is determined from the fractional dose of some representative common indoor air pollutants of unsatisfactory IAQ, either by taking equal importance of the pollutants as a weighting factor or weighted by the regional failure rates with respect to the corresponding air pollutants. Specifically, a database of regional IAQ assessment results of 422 air‐conditioned offices was employed to justify the selected screening levels for the IAQ index.

The proposed IAQ index of a screening assessment was used for verifying, respectively, 58 and seven air‐conditioned offices of Hong Kong with satisfactory and unsatisfactory IAQ. The results showed that 57 satisfactory offices and two unsatisfactory offices were correctly identified by the unweighted and weighted IAQ indices respectively. Evaluation of the proposed index in further IAQ improvements of some offices showed that it would be a practical tool for preliminary IAQ screening assessment.

The screening test itself could not identify all the IAQ problems but could identify the office groups with higher risk of unsatisfactory IAQ with reduced effort.

The study shows the usefulness of the proposed IAQ index to identify the unrecognized IAQ problems for air‐conditioned office environments. It could be adopted as a routine screening measure in facility management of which a wide‐ranging set of IAQ measurement is undesired.

This study presents a useful reference for policymakers, building owners and professionals for indoor environmental assessments.

This study aims to evaluate the generation of food waste in a university and the handling efficiency of an automatic waste collection system.

The quantity of food waste generated and collected from a university canteen was surveyed. The food waste handling efficiencies using manual collection strategy and automated food waste collection system were determined by the density of food waste. Life-cycle costing analysis was done to evaluate the economic impacts of various food waste collection methods.

As compared with the manual collection approach, the automatic system can improve the food waste handling efficiency by 30% (from 0.01 to 0.007 bin kg⁻¹) and reduce the water use by 20% (from 0.512 to 0.406 L kg⁻¹); however, it also consumes 4.4 times more energy (from 0.005 to 0.027 kWh kg⁻¹). Under ideal system operation, the 10-year cost of food waste collection was significantly reduced from $3.45 kg⁻¹ in the manual collection to $1.79 kg⁻¹, and the payback period of the system collection was 1.9 years without discount.

The outcomes of this study show that an automatic food waste collection system is feasible, and it is recommended for small- and medium-sized catering facilities (e.g. canteens and food courts) to improve food waste handling efficiency. This study also provides useful reference data of automatic food waste collection systems for planning food waste management programs for catering facilities.

To the best of the authors’ knowledge, this is the first study to evaluate the waste handling efficiency, operational expenditure and life-cycle cost of a small-scale automatic food waste collection system.

To determine the radon emanation rates of common partition materials in Hong Kong.

An initial slope of radon gas growth against time and a mass balance analysis can be used to quantify the magnitude of these rates from different types of partition materials. In particular, the radon‐222 emanations from boards of calcium silicate, gypsum and lightweight concrete were measured experimentally in a small impervious radon chamber.

The radon‐222 emanations from boards of calcium silicate, gypsum and lightweight concrete were measured experimentally in a small impervious radon chamber, and expressed as becquerels per square meter per hour of air (Bq m⁻² hr⁻¹). The rates found were 2.43, 0.22 and 0.46 Bq m⁻² hr⁽¹ respectively. Comparing with the emanation rate and the quantities of radon emitting construction materials in Hong Kong, these three partition materials have a low radon emitting level.

The model parameters used in the study were not exhaustive and were determined from samples of materials used in Hong Kong.

A useful source of reference for determining the radon emanation rates of common partition materials used in building developments. The results can be used to identify the exposure risk of radon in buildings.

This paper proposes a mathematical model of radon emanation rates of common partition materials. The model offers practical helps to professionals planning, designing and managing the selection of building materials in buildings.

The purpose of this study is to develop a condition assessment (CA) model for a building's indoor 21 environments and to improve the building's asset management process.

The methodology is based on dividing the building into spaces, which are the principal evaluated elements based on the building's indoor environmental quality (IEQ). An evaluation scheme was prepared for the identified factors and the analytical hierarchy process (AHP) technique was used to calculate the relative weight of each space inside the building as well as the contribution of each IEQ factors (IEQFs) in the overall environmental condition of each space inside the building. The multi-attribute utility theory (MAUT) was then applied to assess the environmental conditions of the building as a whole and its spaces. An educational building in Canada was evaluated using the developed model.

Each space type was found to have its own IEQFs weights, which confirms the hypothesis that the importance and allocation of each IEQF are dependent on the function and tasks carried out in each space. A similar indoor environmental assessment score was calculated using the developed model and the building CA conducted by the facility management team; “89%” was calculated, using K-mean clustering, for the physical and environmental conditions.

IEQ affects occupants' assessment of their quality of life (QOL). Despite the existence of IEQ evaluation models that correlate the building's IEQ and the occupants' perceived indoor assessments, some limitations have led to the necessity of developing a comprehensive model that integrates all factors and their sub-criteria in an assessment scheme that converts all the indoor environmental factors into objective metrics.