Building Water Systems Research Articles

HACCP-Based Programs for Preventing Disease and Injury from Premise Plumbing: A Building Consensus

Thousands of preventable injuries and deaths are annually caused by microbial, chemical and physical hazards from building water systems. Water is processed in buildings before use; this can degrade the quality of the water. Processing steps undertaken on-site in buildings often include conditioning, filtering, storing, heating, cooling, pressure regulation and distribution through fixtures that restrict flow and temperature. Therefore, prevention of disease and injury requires process management. A process management framework for buildings is the hazard analysis and critical control point (HACCP) adaptation of failure mode effects analysis (FMEA). It has been proven effective for building water system management. Validation is proof that hazards have been controlled under operating conditions and may include many kinds of evidence including cultures of building water samples to detect and enumerate potentially pathogenic microorganisms. However, results from culture tests are often inappropriately used because the accuracy and precision are not sufficient to support specifications for control limit or action triggers. A reliable negative screen is based on genus-level Polymerase Chain Reaction (PCR) for Legionella in building water systems; however, building water samples with positive results from this test require further analysis by culture methods.

Amendments to the Drinking Water Ordinance: Legionellae in Hot Water Systems - Data from the Public Health Authority Frankfurt am Main, Germany

The first and second amendment to the Drinking Water Ordinance came in to force in the years 2011 and 2012 causing additional tasks and responsibilities for operators of commercial large-scale systems, usually hot water systems in large residential buildings, and for the local health authorities. This article describes the experiences of the health authority in Frankfurt/Main with these new regulations. Some of the revisions in the first amendment of the ordinance (TrinkwV 2001 (2011)) were omitted in the second revision (TrinkwV 2001 (2012)) such as the obligation to notify for large-scale systems. Furthermore, the intervals between the obligatory inspections were extended from 1 to 3 years and merely exceedances of the legal limits were to be notified in contrast to the previous obligation to notify all values. On the basis of the TrinkwV 2001 (2011) a large additional staff requirement had been estimated (13/21 positions). After the TrinkwV 2001 (2012) the tasks can be accomplished by less than 2 employees. While the notification obligation was still in force, the health authority received 4,461 notifications of large-scale systems, since then a further 477 have been notified. Of a total of 1,335 initial analyses, 794 (60%) exceeded the technical action value and in 113 properties with values exceeding 10,000/100 ml a usage restriction was necessary. Due to the suspension of the notification obligation to report any result of the analyses performed the assessment of the reports on large-scale systems has become difficult. An appropriate assessment of the implementation of the regulation is not possible, since the total number of large-scale systems is not known and a failure to report may result from a measured value below the technical action value as well as from a not inspected system. The large number of usage restrictions is an indication for the necessity to inspect and if required to treat and restore the system.

Study on Demand-side Design Parameters of Solar Domestic Hot Water System in Residential Buildings

Abstract Solar domestic hot water system is widely used and developing fast in recent years in China. However many problems occur at the same time, for example more energy consumption by circulation pump, water reheating, long investment payback period, and etc. Through analyzing the field-testing data of projects and investigating of different residential consumers, it was found that compared to actual hot water consumption the solar domestic hot water systems were generally designed too large in capacity, which means the designed hot water demand is much greater than actual user consumption. This study compared different specifications and recommended design parameters value of hot water related standards, and analyzed the calculation methodology and design parameter ofhot water quota. Finally problems in the system design are summarized and suggestions are proposed for designers and different stakeholders.

Factors influencing persistence of Legionella pneumophila serogroup 1 in laboratory cocultures.

BackgroundRisk for infections from Legionella pneumophila for immunocompromised individuals increases greatly when this species is present within the biofilm of the water distribution systems of hospitals or other health facilities. Multiplication and persistence of Legionella may dependent also upon planktonic growth in alternative to sessile growth. Here we compared the persistence of L. pneumophila serogroup 1 in experimental planktonic co-cultures subsided with iron, Pseudomonas aeruginosa and other non Legionella bacteria (quantified as Heterotrophic Plate Count, HPC at 37°C), isolated from drinking water sources of a large hospital.ResultsConcentrations of L. pneumophila showed a decreasing pattern with incubation time in all co-cultures, the degree of reduction depending on the experimental treatment. In co-cultures with added P. aeruginosa, no L. pneumophila was detectable already after 4 days of incubation. In contrast in co-cultures without P. aeruginosa, HPC but not iron were significant factors in explaining the pattern of L. pneumophila, although the HPC effect was different according to the incubation time (HPC x time interaction, p < 0.01).ConclusionsOur results highlight the need of controlling for both HPC and metal constituents of the water systems of buildings used by individuals at particular risk to the effects of Legionella exposure.

Maintaining Legionella control in building water systems

This article reviews how Legionella and other waterborne pathogens can present a risk to consumers of potable water, secondary disinfection options, and a case study on chlorine dioxide.

Residential water heaters in Brisbane, Australia: Thinking beyond technology selection to enhance energy efficiency and level of service

A holistic approach to residential water heating systems specification is required to provide optimal energy efficiency. The objective of this study is to analyse the performance of residential water heating systems for the city of Brisbane in Australia, for different combinations of heating system technologies (solar, heat pump, electric), storage tank sizes (125l, 250l, 325l), time-distribution of energy in accordance to the tariff selection (all-day, controlled, night off-peak) and washing machine water heating sources (internal and external). Performance assessments considered the influence of 54 different water heating system configurations on the electricity grid (i.e. power peaks, time-distribution of energy according to electricity tariffs, and energy intensity), as well as their level of service (i.e. compliance rates with recommended hot water temperatures). Empirical water end use data from 27 households was utilised to model the performance of water heating systems. The study demonstrated that beyond merely specifying the type of technology (e.g. solar hot water), other key criteria such as hot water demand, hot water tank size and electricity tariff selection should also be considered in order to systematically optimise the energy and service performance of hot water systems in residential buildings.

Effects of holding time and measurement error on culturing Legionella in environmental water samples

Outbreaks of Legionnaires' disease require environmental testing of water samples from potentially implicated building water systems to identify the source of exposure. A previous study reports a large impact on Legionella sample results due to shipping and delays in sample processing. Specifically, this same study, without accounting for measurement error, reports more than half of shipped samples tested had Legionella levels that arbitrarily changed up or down by one or more logs, and the authors attribute this result to shipping time. Accordingly, we conducted a study to determine the effects of sample holding/shipping time on Legionella sample results while taking into account measurement error, which has previously not been addressed. We analyzed 159 samples, each split into 16 aliquots, of which one-half (8) were processed promptly after collection. The remaining half (8) were processed the following day to assess impact of holding/shipping time. A total of 2544 samples were analyzed including replicates. After accounting for inherent measurement error, we found that the effect of holding time on observed Legionella counts was small and should have no practical impact on interpretation of results. Holding samples increased the root mean squared error by only about 3–8%. Notably, for only one of 159 samples, did the average of the 8 replicate counts change by 1 log. Thus, our findings do not support the hypothesis of frequent, significant (≥= 1 log10 unit) Legionella colony count changes due to holding.

A Comprehensive Water Management Program for Multicampus Healthcare Facilities

Develop and implement an effective program for hazard analysis and control of waterborne pathogens at a multicampus hospital with clinics. A longitudinal study. Several-year study including analysis of results from monitoring and tests of 26 building water systems. Outpatient and inpatient healthcare facilities network. The hazard analysis and critical control point (HACCP) process was used to develop a water management program (WMP) for the hospital campuses. The HACCP method systematically addressed 3 questions: (1) What are the potential waterborne hazards in the building water systems of these facilities? (2) How are the hazards being controlled? (3) How do we know that the hazards have been controlled? Microbiological and chemical tests of building water samples were used to validate the performance of the WMP; disease surveillance data further validated effective hazard control. Hazard analysis showed that waterborne pathogens were generally in good control and that the water quality was good in all facilities. The hospital network has had several legionellosis cases that were identified as presumptive hospital acquired, but none was confirmed or substantiated by water testing in follow-up investigations. Building water system studies unrelated to these cases showed that pressure tanks and electronic automatic faucets required additional hazard control. Application of the HACCP process for long-term building water systems management was practical and effective. The need for critical control point management of temperature, flow, and oxidant (chlorine) residual concentration was emphasized. The process resulted in discovery of water system components requiring additional hazard control.

A Study on CO&lt;sub&gt;2&lt;/sub&gt; Emission Reduction Planning in the Water Sector in Office Buildings

Energy, CO2 and Water are most important issues that environmental impact in buildings and cities. These are related each other very closely. This study has attempted to analyze CO2 emission by water usages, sewage wastes and also water saving strategies like installation water saving devices, rainwater harvesting and gray water system in office buildings. To assess from the early design stage, should be developed regional water amount and regional CO2 emission factor by water. Consequently, estimated one sample office project in Korea and suggested effective CO2 emission reduction plan in the water sector. Total amount of CO2 emission in the water sector in sample office building is 188.25 t·CO2eq/yr.

Evaluation of Legionella presence in the water system of a public building by semi-nested polymerase chain reaction as a rapid screening method complementary to plate count

The aim of this study was to apply a fast and efficient protocol for monitoring levels of Legionella contamination in high-risk water systems using molecular techniques and culture methods. Forty-nine water samples from a public building were analyzed by a culture method (BCYE agar) and a specific semi-nested polymerase chain reaction (PCR). The first 30 analyses using plate counts were positive in 28% of hot water and 8% of cold water samples. The analysis by PCR, obtained within 24 h of collection, revealed the presence of DNA in 100 and 54% respectively. Only four PCR results coincided with the cultures. A second survey (19 samples) was performed 1 year later. Semi-nested PCR revealed that 53% of the samples were positive; however, plate counts yielded no positive results. The 16S rRNA sequence comparison between the first and second samplings showed 100% homology. In conclusion, the study of the design of the building's water system, the use of a fast screening semi-nested PCR and a culture method for the detection of Legionella allowed accurate assessment of the contamination, thus contributing to the early implementation of measures to eliminate the presence of the bacteria in water systems and consequently reduce a latent public health risk.

Quantitative Assessment of Water Use Efficiency in Urban and Domestic Buildings

This paper discusses the potential of water savings at property, household and urban levels, through the application of environmentally sound technologies (ESTs), as well as their quantification using the software Wise Water. Household centered measures are identified that allow for significant reduction of drinking water consumption with comparatively small effort, and without limitation of comfort. Furthermore, a method for the estimation of water recycling, for rainwater harvesting and for the utilization potential as locally available renewable freshwater is presented. Based on this study, the average drinking water consumption in urban households of industrialized countries could be reduced by approximately one third, without significant investment costs, either within the framework of new constructions or by the remodeling of water and sanitation systems in residential buildings. By using a secondary water quality, the drinking water demand could even be reduced by 50%. In the case of an area-wide application, the overall fresh water demand of cities and the exploitation of fresh water resources could be significantly reduced. Due to the comparability of the domestic water use of the investigated households, the findings are internationally transferable, for example to countries in Europe, Asia, and also the USA.

Legionella pneumophila in healthcare facilities

Legionella pneumophila are gram-negative bacteria found in freshwater environments; they can survive as intracellular parasites of free-living protozoa and within biofilms in building water systems. L. pneumophila multiply at temperatures between 25 and 42 degrees C, with an optimal growth temperature of 35 degrees C. There are 16 serogroups of L. pneumophila. In Europe, approximately 70% of Legionella infections are caused by L. pneumophila serogroup 1 and 20-30% by other serogroups. These bacteria cause respiratory disease (legionellosis) in humans when a susceptible host inhales aerosolized water containing the bacteria or aspirates water containing the bacteria. Legionellosis classically presents as two distinct clinical entities: Legionnaires' disease, a severe multisystem disease involving pneumonia, and Pontiac fever, a self-limited flu-like illness. Urine antigen tests and cultures of sputum or bronchoalveolar lavage are the most suitable clinical laboratory tests for Legionella. The new macrolide antibiotics, such as clarithromycin and azithromycin, show more effective in-vitro activity and a better intracellular and tissue penetration than erythromycin, as do the quinolones. Hospitals represent ideal locations for Legionnaires' disease transmission: at-risk individuals are present in large numbers; plumbing systems are frequently old and complex, favouring multiplication of the organism; and water temperatures are often reduced to prevent scalding of patients. Safe water is vital to ensure patient safety and reduce costs where waterborne infections cause increasing morbidity, mortality, treatment costs, longer hospital stays and compensation claims. The WHO has developed Water Safety Plans for preventing or controlling the risks through system assessment, monitoring, surveillance and management/communication, so that health outcomes can be improved, that is a systematic approach is required to secure microbial safety.

Heat Consumption Assessment of the Domestic Hot Water Systems in the Apartment Buildings

This study presents the analysis of energy consumption for domestic hot water in apartment buildings in Riga, Latvia. The aggregate data contains information about 39 apartment buildings, including heat energy consumption and domestic hot water (DHW) consumption. The analysis is focused on the heat energy consumption and seasonal characteristics in the DHW system. The analysis characterizes the DHW consumption, energy consumption for DHW and energy losses in the DHW systems in apartment buildings. The energy consumption of DHW needs of households and some other building sectors constitutes a significant part of the building's energy balance. The building energy efficiency improvement measures reduce the heating energy required proportion and logically increase the share of energy consumption for DHW needs. It is likely that the production and distribution of DHW in buildings will constitute a dominant share of both the present, and in particular, the future energy design requirements of buildings. (1) Previously studies carried out in various European countries (2), (3), (4), China (5), (6), Japan (7), (8), (9), USA (10), (11), Canada (12) points the many differences in DHW consumption as well as the tendency to change over time due to a global increase of energy prices, changes in technologies, introducing of individual metering, as well as wide variety of other factors that may appear on local or regional level. Measurements in Denmark documented not only a relatively high energy consumption for DHW in apartment buildings, but also recorded surprisingly large heat losses from the DHW circulation lines (13), (14). Recent investigation of 24 buildings in Danmark shows that most of the energy demand for DHW is lost in the circulation system. The efficiency was 0.30-0.77 (heat loss 23-70%) in apartment buildings and efficiency 0.11- 0.46 (heat loss 54-89%) in office buildings. (1) The Energy Performance of Buildings Directive (EPBD) (15) in the version of 2010, the so-called recast EPBD, demands in annex I 'Common general framework for the calculation of energy performance of buildings (referred to in Article 3)' that '(1) the energy performance of a building shall be determined on the basis of the calculated or actual annual energy that is consumed in order to meet the different needs associated with its typical use and shall reflect the heating energy needs and cooling energy needs (energy needed to avoid overheating) to

Development of a stratified tank storage component for ESP-r with embedded phase change material modules

Solar domestic hot water systems are very common and are considered an efficient system for exploiting the renewable energy source of the sun, for instance national Italian regulations require the adoption of solar domestic hot water systems in new buildings. Water tanks are typical components for such systems, but have a serious drawback since they require a great amount of space in buildings. In this article, a new water tank model with embedded phase change material modules for the ESP-r code is presented in order to assess the possibility of using reduced size water tanks with additional latent storage. This article describes the numerical model used to deal with phase change phenomena and the incorporation of the method into ESP-r source code. To validate the model, the results of a test case have been compared with the literature data. A typical solar domestic hot water system has been simulated in order to study the impact of the phase change material modules inside tanks on the energy performance of the system. The results are reported using a global parameter that represents the fractional primary energy saved using the solar system. Water temperature plots with and without phase change material have been reported as well.

Postantibiotic effect of various antibiotics on Legionella pneumophila strains isolated from water systems

The postantibiotic effects (PAE) of azithromycin, clarithromycin, ciprofloxacin, and levofloxacin were investigated against Legionella pneumophila (L. pneumophila) strains isolated from several hot water systems of different buildings in Istanbul. Each strain in logarithmic phase of growth was exposed to concentrations of antibiotics equal to minimum inhibitory concentration (MIC) and 4× MIC for 1h. Recovery periods of test cultures were evaluated after centrifugation using the viable counting method. The mean values of PAEs for the strains of L. pneumophila, azithromycin at a concentration equal to and 4 times of MIC values were found 1.75 ± 0.28 h and 4.06 ± 0.44h, for clarithromycin 2.98 ± 0.70h and 4.18 ± 0.95h, for ciprofloxacin 2.97 ± 0.63h and 4.70 ± 0.63h, for levofloxacin 2.05 ± 0.33h and 3.78 ± 0.46h, respectively. All of the antibiotics showed increased PAE values in a concentration-dependent manner. The findings of our study may play useful role in selecting the appropriate timing of doses during therapy with antimicrobials to treat patients infected with L. pneumophila.

Inaccuracy in Legionella tests of building water systems due to sample holding time

Most Legionella culture tests are performed on building water samples that have been shipped to analytical laboratories for analysis. Significant (≥1 log10 unit) changes in results were observed in 52% of held samples (6 h or longer, ambient temperature) drawn from building water systems in a 42-sample initial survey. It was not practical to use the spread plate protocol for on-site “t = 0” cultures in a larger, more diverse survey of thousands of building water systems. Two thousand four hundred twenty-one (2421) building water samples were split for on-site analysis using a field culture protocol and then also cultured after overnight shipment to the lab for analysis with the standardized spread plate method. Legionella test results from building water system samples are usually interpreted as ≥a numerical detection or action limit. Therefore, binary statistical analyses were calculated by setting t = 0 culture results to “true”. Overall in this survey, 10.4% of water samples sent to the laboratory for analysis returned either false-positive or false-negative results. The overall positive predictive value of results was poor (36%). Most (83%) false-positive results were returned from utility water systems. Most (74%) false-negative results were returned from potable water systems. These inaccuracies have serious implications in regard to interpretation and use of Legionella test results. The overall negative predictive value of results was excellent (99%) and also it was good (92%) for results from a polymerase chain reaction (PCR) assay that can be therefore used as a negative screening method.

A fault-tolerant and energy efficient control strategy for primary–secondary chilled water systems in buildings

Primary–secondary chilled water systems with decoupled bypass in building air-conditioning often cannot work in healthy condition as desired in practical operation, due to excess secondary flow demand resulting in deficit flow in the bypass line. This paper presents a fault-tolerant and energy efficient control strategy for secondary chilled water pump systems to solve this operation and control problem providing enhanced operation performance and energy efficiency of chilled water systems. The strategy employs the flow-limiting technique that ensures the water flow of secondary loop not exceed that of the primary loop while still maintaining highest possible delivery capacity of cooling to terminals. The strategy is also integrated with a differential pressure set-point optimizer to determine the optimal set-point. The performance of this strategy is evaluated in a simulated real-life environment representing the chilled water system in a super high-rise building by comparing it with two conventional control strategies. Results show that the proposed strategy can effectively eliminate the deficit flow at both starting and normal operation periods. The energy saving in the secondary chilled water pumps can be up to over 70% and 50% at system starting and normal operation periods respectively compared with the other strategies.

Water Management Plan to Prevent Disease Associated with Building Water Systems

An algorithm providing guidance on appropriate venous access devices. A list of nurses with enhanced peripheral IV placement proficiency. Physician order sets and transfer orders that identify PICC/CVC indications. Discharge orders that identify patients discharged with PICC/CVC, the responsible provider, and the stop date for the PICC/CVC and medications. Patient education sheet for PICC/CVC. Situation, Background, Assessment, Recommendation (SBAR) handover tool. The Associate Administrator of Nursing chaired the PI team, provided education to physician committees, and participated in unit based education sessions with staff.

The Implication of Solar Hot Water System in Small High-Rise Buildings

It introduces small high-rise building concepts, discusses the calculation of solar hot water system, which includes the collection of raw data, the determination of solar collector area, the size of heat storage water tank and hot water system type as well as summarizes it as a reference for engineering design.

PCR-coupled electrochemical sensing of Legionella pneumophila

Human infections with Legionella pneumophila represent a public health problem. Current culture assays for surveillance and control of L. pneumophila in water are time-consuming and limited by the sensitivity, especially when samples also contain microorganisms that inhibit Legionella growth. In this work, an electrochemical method, different from real-time polymerase chain reaction (PCR) approaches, for semiquantitative evaluation of L. pneumophila is presented. A PCR assay targeting the 16S-rRNA gene of L. pneumophila giving rise to a 95-mer amplicon was established. Amplicons were hybridized to a biotin-labeled reporter sequence and then to a thiolated stem-loop structure immobilized onto gold electrodes as a reporter molecule with 1-naphthyl phosphate as a substrate. 1-Naphthol enzymatically generated was determined by differential pulse voltammetry (DPV). For a constant number of amplification cycles, results show that the voltammetric signal is related to the number of copies in the sample thus achieving a useful semiquantitative estimation of L. pneumophila. After 40 cycles of PCR amplification this methodology has a limit of detection of 10 genomes, allowing the reliable detection of 102 genomes of L. pneumophila as well as distinguishing 103 and 104 genomes of the pathogen, values related to corrective actions in water systems in buildings, in accordance with the legislation currently in force.