A Modeling Approach for Quantifying Exposures from Emissions of Spray Polyurethane Foam Insulation in Indoor Environments PDF Download
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Author: Charles Bevington
Publisher:
ISBN:
Category : Indoor air pollution
Languages : en
Pages : 29
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Book Description
A range of chemicals from very volatile to semivolatile organic compounds are emitted from spray polyurethane foam (SPF) insulation. SPF installation procedures and environments can vary widely, and the emissions, transport, and fate of these chemicals in the indoor environment after SPF installation are not well characterized. To begin to understand exposure to emissions from SPF and to identify and characterize the uncertainty in assessing chemical exposures, a proof-of-concept multizone indoor model was developed to estimate indoor air concentrations of chemicals emitted from SPF over time. The model supported the development of different approaches for characterizing the emissions of volatile and semivolatile organic compounds and for predicting short- and long-term emissions and subsequent air concentrations. It also incorporated estimates for a wide range of parameters that influence emission and subsequent exposure from SPF. A sensitivity analysis was performed to explore the impact of model inputs, including those considered the most influential and those for which there is uncertainty because of a lack of data. Model inputs included the location and type of SPF foam; the chemical-specific diffusion and partitioning coefficients; the temperature and ventilation rates of zones within the residence; and the impact of engineering controls, such as increased ventilation during installation. Sensitivity analysis results identified trends and relations between model inputs and outputs. Additional experimental data are needed to calibrate the model and to reduce uncertainty of model estimates. In particular, information is needed to characterize emissions within the first 24 h after spray application, to characterize longer-term mass transfer of chemicals from SPF, and to describe interzonal air flow and leakage rates between attics, living spaces, and crawl spaces.
Author: Charles Bevington
Publisher:
ISBN:
Category : Indoor air pollution
Languages : en
Pages : 29
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Book Description
A range of chemicals from very volatile to semivolatile organic compounds are emitted from spray polyurethane foam (SPF) insulation. SPF installation procedures and environments can vary widely, and the emissions, transport, and fate of these chemicals in the indoor environment after SPF installation are not well characterized. To begin to understand exposure to emissions from SPF and to identify and characterize the uncertainty in assessing chemical exposures, a proof-of-concept multizone indoor model was developed to estimate indoor air concentrations of chemicals emitted from SPF over time. The model supported the development of different approaches for characterizing the emissions of volatile and semivolatile organic compounds and for predicting short- and long-term emissions and subsequent air concentrations. It also incorporated estimates for a wide range of parameters that influence emission and subsequent exposure from SPF. A sensitivity analysis was performed to explore the impact of model inputs, including those considered the most influential and those for which there is uncertainty because of a lack of data. Model inputs included the location and type of SPF foam; the chemical-specific diffusion and partitioning coefficients; the temperature and ventilation rates of zones within the residence; and the impact of engineering controls, such as increased ventilation during installation. Sensitivity analysis results identified trends and relations between model inputs and outputs. Additional experimental data are needed to calibrate the model and to reduce uncertainty of model estimates. In particular, information is needed to characterize emissions within the first 24 h after spray application, to characterize longer-term mass transfer of chemicals from SPF, and to describe interzonal air flow and leakage rates between attics, living spaces, and crawl spaces.
Author: John Sebroski
Publisher:
ISBN:
Category : Insulation (Heat)
Languages : en
Pages : 26
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Book Description
Consensus standards are being developed at ASTM International to identify potential emissions from spray polyurethane foam (SPF) insulation products and to evaluate their impact on indoor air quality after installation. A method is currently being developed to measure emissions of SPF insulation using micro-scale chambers. In order to evaluate emission decay rates and the effects of temperature, generic SPF formulations (closed-cell and open-cell) were tested for emissions in micro-scale chambers (0.114 L) at ambient (23°C) and two elevated temperatures (40 and 65°C) for 20 days. Small-scale chamber (36-L) tests were conducted simultaneously to correlate the emission factors that were measured with the micro-scale chambers. Thermal desorption gas chromatography-mass spectrometry was used to capture and quantitate target volatile organic compounds (blowing agents, amine catalysts, etc.) and the flame retardant used in both formulations. Aldehydes were captured onto silica gel sorbent tubes with dinitrophenylhydrazine and analyzed with high-performance liquid chromatography. After the application of open-cell SPF, the outer skin layer of the foam may be trimmed to align the surface with wall studs or other structural elements. In this case, it may be necessary to mimic this practice when preparing samples for analyses to measure emissions. In order to investigate the impact of emissions on trimmed SPF samples, micro-scale chamber studies were conducted on both trimmed and untrimmed generic open-cell SPF material for comparison. The data from this study demonstrate that micro-scale chambers can be used to identify and quantitate potential emissions from SPF insulation. The findings from this research will be used to support the development of consensus standards in ASTM Committee D22 on Air Quality, Subcommittee D22.05 on Indoor Air.
Author: John Sebroski
Publisher:
ISBN: 9780803176232
Category :
Languages : en
Pages :
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Author: Kevin J. Dowding
Publisher:
ISBN:
Category :
Languages : en
Pages : 72
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Book Description
Enhanced software methodology and improved computing hardware have advanced the state of simulation technology to a point where large physics-based codes can be a major contributor in many systems analyses. This shift toward the use of computational methods has brought with it new research challenges in a number of areas including characterization of uncertainty, model validation, and the analysis of computer output. It is these challenges that have motivated the work described in this report. Approaches to and methods for model validation and (model-based) prediction have been developed recently in the engineering, mathematics and statistical literatures. In this report we have provided a fairly detailed account of one approach to model validation and prediction applied to an analysis investigating thermal decomposition of polyurethane foam. A model simulates the evolution of the foam in a high temperature environment as it transforms from a solid to a gas phase. The available modeling and experimental results serve as data for a case study focusing our model validation and prediction developmental efforts on this specific thermal application. We discuss several elements of the ''philosophy'' behind the validation and prediction approach: (1) We view the validation process as an activity applying to the use of a specific computational model for a specific application. We do acknowledge, however, that an important part of the overall development of a computational simulation initiative is the feedback provided to model developers and analysts associated with the application. (2) We utilize information obtained for the calibration of model parameters to estimate the parameters and quantify uncertainty in the estimates. We rely, however, on validation data (or data from similar analyses) to measure the variability that contributes to the uncertainty in predictions for specific systems or units (unit-to-unit variability). (3) We perform statistical analyses and hypothesis tests as a part of the validation step to provide feedback to analysts and modelers. Decisions on how to proceed in making model-based predictions are made based on these analyses together with the application requirements. Updating modifying and understanding the boundaries associated with the model are also assisted through this feedback. (4) We include a ''model supplement term'' when model problems are indicated. This term provides a (bias) correction to the model so that it will better match the experimental results and more accurately account for uncertainty. Presumably, as the models continue to develop and are used for future applications, the causes for these apparent biases will be identified and the need for this supplementary modeling will diminish. (5) We use a response-modeling approach for our predictions that allows for general types of prediction and for assessment of prediction uncertainty. This approach is demonstrated through a case study supporting the assessment of a weapons response when subjected to a hydrocarbon fuel fire. The foam decomposition model provides an important element of the response of a weapon system in this abnormal thermal environment. Rigid foam is used to encapsulate critical components in the weapon system providing the needed mechanical support as well as thermal isolation. Because the foam begins to decompose at temperatures above 250 C, modeling the decomposition is critical to assessing a weapons response. In the validation analysis it is indicated that the model tends to ''exaggerate'' the effect of temperature changes when compared to the experimental results. The data, however, are too few and to restricted in terms of experimental design to make confident statements regarding modeling problems. For illustration, we assume these indications are correct and compensate for this apparent bias by constructing a model supplement term for use in the model-based predictions. Several hypothetical prediction problems are created and addressed. Hypothetical problems are used because no guidance was provided concerning what was needed for this aspect of the analysis. The resulting predictions and corresponding uncertainty assessment demonstrate the flexibility of this approach.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
We evaluated three exposure models with data obtained from measurements among workers who use"aerosol" solvent products in the vehicle repair industry and with field experiments using these products to simulate the same exposure conditions. The three exposure models were the: 1) homogeneously-mixed-one-box model, 2) multi-zone model, and 3) eddy-diffusion model. Temporally differentiated real-time breathing zone volatile organic compound (VOC) concentration measurements, integrated far-field area samples, and simulated experiments were used in estimating parameters, such as emission rates, diffusivity, and near-field dimensions. We assessed differences in model input requirements and their efficacy for predictive modeling. The One-box model was not able to resemble the temporal profile of exposure concentrations, but it performed well concerning time-weighted exposure over extended time periods. However, this model required an adjustment for spatial concentration gradients. Multi-zone models and diffusion-models may solve this problem. However, we found that the reliable use of both these models requires extensive field data to appropriately define pivotal parameters such as diffusivity or near-field dimensions. We conclude that it is difficult to apply these models for predicting VOC exposures in the workplace. However, for comparative exposure scenarios in life-cycle assessment they may be useful.
Author:
Publisher:
ISBN:
Category : Air quality
Languages : en
Pages : 40
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Book Description
Author: A A Stec
Publisher: Elsevier
ISBN: 184569807X
Category : Medical
Languages : en
Pages : 721
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Book Description
Toxic fire effluents are responsible for the majority of fire deaths, and an increasing large majority of fire injuries, driven by the widespread and increasing use of synthetic polymers. Fire safety has focused on preventing ignition and reducing flame spread through reducing the rate of heat release, while neglecting the important issue of fire toxicity. This is the first reference work on fire toxicity and the only scientific publication on the subject in the last 15 years. Assessment of toxic effects of fires is increasingly being recognised as a key factor in the assessment of fire hazards. This book raises important issues including the types of toxic effluents that different fires produce, their physiological effects, methods for generation and assessment of fire toxicity, current and proposed regulations and approaches to modelling the toxic impact of fires. The contributors to Fire toxicity represent an international team of the leading experts in each aspect of this challenging and important field. This book provides an important reference work for professionals in the fire community, including fire fighters, fire investigators, regulators, fire safety engineers, and formulators of fire-safe materials. It will also prove invaluable to researchers in academia and industry. Investigates the controversial subject of toxic effluents as the cause of the majority of fire deaths and injuries Describes the different types of toxic effluents and the specific fires that they produce, their physiological effects and methods for generation Provides an overview of national and international fire safety regulations including current and proposed regulations such as a standardized framework for prediction of fire gas toxicity
Author: Fernando Pacheco-Torgal
Publisher: Elsevier
ISBN: 0857096354
Category : Technology & Engineering
Languages : en
Pages : 504
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Book Description
From long-standing worries regarding the use of lead and asbestos to recent research into carcinogenic issues related to the use of plastics in construction, there is growing concern regarding the potential toxic effects of building materials on health. Toxicity of building materials provides an essential guide to this important problem and its solutions.Beginning with an overview of the material types and potential health hazards presented by building materials, the book goes on to consider key plastic materials. Materials responsible for formaldehyde and volatile organic compound emissions, as well as semi-volatile organic compounds, are then explored in depth, before a review of wood preservatives and mineral fibre-based building materials. Issues related to the use of radioactive materials and materials that release toxic fumes during burning are the focus of subsequent chapters, followed by discussion of the range of heavy metals, materials prone to mould growth, and antimicrobials. Finally, Toxicity of building materials concludes by considering the potential hazards posed by waste based/recycled building materials, and the toxicity of nanoparticles.With its distinguished editors and international team of expert contributors, Toxicity of building materials is an invaluable tool for all civil engineers, materials researchers, scientists and educators working in the field of building materials. - Provides an essential guide to the potential toxic effects of building materials on health - Comprehensively examines materials responsible for formaldehyde and volatile organic compound emissions, as well as semi-volatile organic compounds - Later chapters focus on issues surrounding the use of radioactive materials and materials that release toxic fumes during burning
Author: D. C. Allport
Publisher: John Wiley & Sons
ISBN: 9780471958123
Category : Science
Languages : en
Pages : 470
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Book Description
- MDI und TDI sind Diisocyanate, die industriell als Bausteine für Polymere verwendet werden, aber für die Gesundheit und die Umwelt nicht unbedenklich sind - erstmals werden hier Gesundheits- und Umweltrisiken von TDI und MDI gezielt in einem Band angesprochen - mit zahlreichen Photos, Spektren, Tabellen und Diagrammen - Beiträge von Experten aus Forschung, Industrie und Behörden
