A scale model to evaluate water evaporation from indoor swimming pools

The evaluation of water evaporation from indoor swimming pools is a topic of considerable practical interest, since evaporation may cause the highest energy consumption of the pool plant. A purposely designed experimental apparatus was used to measure the water evaporation rate from a pool scale model inserted into a climatic chamber to control environmental conditions. The experimental data were obtained varying various parameters such as water temperature, air temperature, relative humidity and air velocity. The results were used to propose a prediction model for water evaporation which was compared to other methods found in the literature, showing a good agreement.     

室内游泳池水面蒸发量计算公式的探讨

基于实测数据对计算室内游泳池水面蒸发量的多个公式的可靠性进行检验和对比,为工程设计合理选用计算公式提出了建议。     

Volatile disinfection by-product analysis from chlorinated indoor swimming pools

Chlorination of indoor swimming pools is practiced for disinfection and oxidation of reduced compounds that are introduced to water by swimmers. However, there is growing concern associated with formation for chlorinated disinfection by-products (DBPs) in these settings. Volatile DBPs are of particular concern because they may promote respiratory ailments and other adverse health effects among swimmers and patrons of indoor pool facilities. To examine the scope of this issue, water samples were collected from 11 pools over a 6 month period and analyzed for free chlorine and their volatile DBP content. Eleven volatile DBPs were identified: monochloramine (NH₂Cl), dichloramine (NHCl₂), trichloramine (NCl₃), chloroform (CHCl₃), bromoform (CHBr₃), dichlorobromomethane (CHBrCl₂), dibromochloromethane (CHBr₂Cl), cyanogen chloride (CNCl), cyanogen bromide (CNBr), dichloroacetonitrile (CNCHCl₂), and dichloromethylamine (CH₃NCl₂). Of these 11 DBPs, 10 were identified as regularly occurring, with CHBrCl₂ only appearing sporadically. Pool water samples were analyzed for residual chlorine compounds using the DPD colorimetric method and by membrane introduction mass spectrometry (MIMS). These two methods were chosen as complementary measures of residual chlorine, and to allow for comparisons between the methods. The DPD method was demonstrated to consistently overestimate inorganic chloramine content in swimming pools. Pairwise correlations among the measured volatile DBPs allowed identification of dichloromethylamine and dichloroacetonitrile as potential swimming pool water quality indicator compounds.     

Analysis of indoor environmental conditions and heat pump energy supply systems in indoor swimming pools

For indoor swimming pools, a lot of energy is needed to control the indoor temperature, relative humidity and pool water temperature. Meanwhile, the indoor air contains a high specific enthalpy due to water evaporation. A new heat pump dehumidifier is studied to reduce energy consumption. The most significant feature of this system is that it can not only recover the latent heat from indoor moist air, but also absorb heat from outdoor air to heat the indoor air and pool water. First, indoor environmental conditions, including space parameters and pool temperature, are analyzed based on human thermal comfort and energy saving. Subsequently, the models of heat and moisture gain are built. After that, the construction and operating modes of the heat pump dehumidifier are described, and the system model is established based on polynomial equations model. In a case study, an indoor swimming pool with a heat pump dehumidifier in Shanghai is studied. When outdoor air specific enthalpy is higher than 18.6 kJ/kg, the requirement of pool water heating can be met only by the heat pump dehumidifier, thus, auxiliary pool heater will not to be put into use. At last, economic analysis between the heat pump dehumidifier and conventional dehumidifier is conducted.     

Trihalomethane exposures in indoor swimming pools: a level III fugacity model

The potential for generation of disinfection byproducts (DBPs) in swimming pools is high due to the concentrations of chlorine required to maintain adequate disinfection, and the presence of organics introduced by the swimmers. Health Canada set guidelines for trihalomethanes (THMs) in drinking water; however, no such guideline exists for swimming pool waters. Exposure occurs through ingestion, inhalation and dermal contact in swimming pools. In this research, a multimedia model is developed to evaluate exposure concentrations of THMs in the air and water of an indoor swimming pool. THM water concentration data were obtained from 15 indoor swimming pool facilities in Quebec (Canada). A level III fugacity model is used to estimate inhalation, dermal contact and ingestion exposure doses. The results of the proposed model will be useful to perform a human health risk assessment and develop risk management strategies including developing health-based guidelines for disinfection practices and the design of ventilation system for indoor swimming pools.     

室内游泳馆冬季防结露设计分析

针对室内游泳馆冬季围护结构内表面结露的问题,对室内设计参数的选择及散湿量的计算进行分析。给出了不同季节的运行控制模式。介绍了游泳池室内温度场、湿度场和速度场的CFD模拟结果。结果表明,局部区域可能出现结露现象,提出应对薄弱部位采取加强措施。     

游泳馆内冬季足部寒冷的解决方法

给出了舒适环境下的足部温度值,分析了冬季室内游泳馆导致足部寒 因素,并提出了３各解决办法。     

酒店室内游泳池防水维修工艺

介绍了西安某酒店五楼的室内游泳池采用暴露型单组分聚脲涂料进行防水维修的施工工艺。     

Exposure levels to brominated compounds in seawater swimming pools treated with chlorine

Despite evidence of formation of brominated compounds in seawater swimming pools treated with chlorine, no data about exposure levels to these compounds have been reported. To address this issue, a survey has been carried out in four establishments (representing 8 pools) fed with seawater and devoted to relaxing and cure treatments (thalassotherapy centres located in Southeast of France). Carcinogenic and mutagenic brominated disinfection byproducts (trihalomethanes -THM- and halogenated acetic acids -HAA-) were quantified at varying levels, statistically related to organic loadings brought by bathers, and not from marine organic matter, and also linked to activities carried out in the pools (watergym vs swimming). Bromoform and dibromoacetic acid, the most abundant THM and HAA detected, were measured at levels up to 18-fold greater than the maximum contaminant levels of 60 and 80 μg/L fixed by US.EPA in drinking waters. The correlations between these disinfection byproducts and other environmental factors such as nitrogen, pH, temperature, free residual chlorine, UV₂₅₄, chloride and bromide concentrations, and daily frequentation were examined. Because thalassotherapy and seawater swimming pools (hotels, cruise ships,…) are increasing in use around the world and because carcinogenic and mutagenic brominated byproducts may be produced in chlorinated seawater swimming pools, specific care should be taken to assure cleanliness of users (swimmers and patients taking the waters) and to increase water circulation through media filters to reduce levels of brominated byproducts.     

室内游泳池的改进措施

简要介绍了室内游泳池的处理过程 ,重点阐述了水处理系统中平衡池、混凝剂选择、过滤装置、消毒等工艺 ,提出了中水系统、室内通风换气等改进意见 ,对保证水温、水质 ,提高循环利用率有重要意义。     

Occupational exposure to natural radiation

Natural sources of radiation can make an important contribution to the exposures of people at work. Two areas of ine interest are work with minerals having elevated concentrations of activity and work in buildings where radon daughter concentrations are elevated.The Euratom Directive on ionising radiation requires that the handling of radioactive substances be reported to national authorities. National authorities may waive this requirement where the activity per unit mass is below 100 Bq g^?1, or for solid natural radioactive substances, 500 Bq g^?1. An investigation was undertaken in five factories to determine whether work with minerals having levels of natural activity below these might lead to significant doses. Models based on the data collected were used to relate the activity in the minerals to the effective dose equivalent arising from gamma radiation, inhalation ohow that the activity, and intake of long-lived activity. These assessments show that the activity concentration at which exposures to airborne dust could lead to doses equal to one-tenth of the dose limit for workers are 0.3 Bq G^?1 for thorium-232 and 1 Bq g^?1 for uranium-238. Above these values, radiological supervision may be necessary.In a separate study, measurements of radon daughter concentrations were made in seventy workplaces. Concentrations in some premises approached or exceeded the derived air concentration for occupational exposure. The highest concentrations were found in premises with low ventilation rates.     

北京室内游乐馆结构设计

介绍了北京室内游乐馆的结构体系、结构规则性、荷载分项系数、材料等内容,并进行了多遇地震内力分析、性能化分析和设计以及基础分析,结果表明:该设计满足规范要求,达到了预期目标。     

Effects of indoor drinking water handling on trihalomethanes and haloacetic acids

In this study, different tap water handling strategies were investigated to evaluate the effects on two principal chlorinated DBPs, trihalomethanes (THMs) and haloacetic acids (HAAs). Tap water samples collected in the Quebec City (Canada) distribution system on a spatio-temporal basis were subjected to diverse indoor handling scenarios: storing water in the refrigerator, boiling water followed by storage and, finally, filtering water with a point-of-use commercial pitcher also followed by storage. In the first two cases, the use of covered and uncovered pitchers was investigated separately, while in the last case, both the use of new and used filters was compared. In all cases, maximum storage time was 48h. Results demonstrated that in some cases, water handling scenarios have considerable effect, and in other cases, little or no effect. Removal of THM concentrations by simple storage was high (on average 30%) and very high by boiling and filtering with subsequent storage in the refrigerator (on average, 87% and 92%, respectively). In scenarios where water was stored in uncovered pitchers (with or without previous boiling and filtering), the THM decrease was higher for increased storage times. However, storage did not have any effect on HAAs, whereas boiling decreased levels of trichloroacetic acid (TCAA) (on average 42%) and increased levels of dichloroacetic acid (DCAA) (on average 35%), resulting in unchanged average levels of total HAAs. The use of the filtration pitcher decreased HAA levels dramatically (on average 66%). Percentages of change in chlorinated DBPs in the different scenarios varied according to initial concentrations in tap water (baseline water), that is, according to the spatio-temporal variations of these substances in the distribution system. On the basis of these results, the paper discusses implications regarding public health protection and exposure assessment for epidemiological studies.     

Occupational exposure to lead in ancient times

The uses and regional production of lead in ancient times are summarized. Since there is no evidence to suggest that any deliberate attempts were made to curtail personal exposure to the mine dusts or the emissions from the forges and crucibles, it is surmised that many of the ancient artisans who worked with lead probably contracted plumbism. The number of workers so exposed is estimated to be over 140,000 per year during the Roman Empire. The ancient literary records of work-related plumbism, however, are surprisingly sparse.     

Risk from exposure to trihalomethanes during shower: Probabilistic assessment and control

Exposure to trihalomethanes (THMs) through inhalation and dermal contact during showering and bathing may pose risks to human health. During showering and bathing, warm water (35 °C-45 °C) is generally used. Warming of chlorinated supply water may increase THMs formation through enhanced reactions between organics and residual chlorine. Exposure assessment using THMs concentrations in cold water may under-predict the possible risks to human health. In this study, THMs concentrations in warm water were estimated by developing a THMs formation rate model. Using THMs in warm water, cancer and non-cancer risks to human health were predicted for three major cities in Ontario (Canada). The parameters for risk assessments were characterized by statistical distributions. The total cancer risks from exposure to THMs during showering were predicted to be 7.6 × 10^− 6, 6.3 × 10^− 6 and 4.3 × 10^− 6 for Ottawa, Hamilton and Toronto respectively. The cancer risks exceedance probabilities were estimated to be highest in Ottawa at different risk levels. The risks through inhalation exposure were found to be comparable (2.1 × 10^− 6-3.7 × 10^− 6) to those of the dermal contact (2.2 × 10^− 6-3.9 × 10^− 6) for the cities. This study predicted 36 cancer incidents from exposure to THMs during showering for these three cities, while Toronto contributed the highest number of possible cancer incidents (22), followed by Ottawa (10) and Hamilton (4). The sensitivity analyses showed that health risks could be controlled by varying shower stall volume and/or shower duration following the power law relationship.     

室内游泳馆防结露控制模式分析

为解决结露问题，从自控角度，按开馆和闭馆两种状态，对室内游泳馆空气温湿度进行了分析，通过降低室内空气湿度，使室内游泳馆的空气露点温度低于围护结构的内表面温度；同时提出实现自然通风的外部条件。