Urea-formaldehyde Foam Insulation Research Articles

Prefabricated Dome Structures with Walls Made of Soil Composites and Urea-Formaldehyde Foam Insulation (UFFI) as a Way to Solve Transport Infrastructure Problems in Permafrost Regions

The territory of Russia extends from West to East for more than 10 thousand kilometres. Recently, this land has become of strategic importance on the international arena. The future development of Russia and its international situation will largely depend on the timely development of these territories. The development of infrastructure in permafrost regions requires the use of not only special construction technologies and materials, but also special design solutions that can reduce further operating costs, while maintaining the most comfortable conditions for human life and activities

Indoor Air Pollution: An Old Problem with New Challenges

Hazards in our indoor environments have been recognized since biblical times. The advice in Leviticus 14:33–48 for treating mold infested houses has contemporary meaning in the recent World Health Organization (WHO) document on damp and moldy indoor spaces [1]. In the developed world, faulty combustion, carbon monoxide from coal gas, lead paint, poor ventilation of tenement housing and hospitals have been recognized for decades as unhealthy. Indoor air quality, however, was not appreciated as an important component of public health until the proliferation of sealed buildings, energy conservation programs (urea formaldehyde foam insulation), new products, and the recognition of the health effects of radon, asbestos and latex. [...]

Reducing formaldehyde exposure in office environments using plants.

Formaldehyde is a toxic substance with adverse health effects detectable at low concentrations. Formaldehyde causes irritation of the eyes, skin and respiratory tract, wheezing, nausea, coughing, diarrhoea, vomiting, dizziness and lethargy at levels as low as 50 parts per billion (ppb) (0.05 ppm) (Horvath et al, 1988). Formaldehyde has also been associated with aggravation of asthma, emphysema, hayfever and allergy problems at low levels (EPA, 1987). Formaldehyde is currently considered a potential carcinogen to humans (EPA, 1987). Formaldehyde is a ubiquitous gas found in elevated concentrations in indoor environments. Concentrations of formaldehyde are typically an order of magnitude greater inside buildings compared to outdoor air (Godish, 1990). Formaldehyde concentrations are particularly high in portable buildings due to the presence of more formaldehyde emitting materials and the relatively smaller interior volumes of air (Sexton et al, 1983). Major sources of formaldehyde indoors are pressed wood products, such as particle board and plywood (Elbert, 1995: Myer and Hermans, 1985), and urea formaldehyde foam insulation (Spengler and Sexton, 1983). Other sources include carpets, curtains, floor linings, paper products, cosmetics and soaps, tobacco smoke and gas combustion (Spengler and Sexton, 1983: Godish, 1990). Methods to reduce indoor formaldehyde include source removal or use of non- polluting materials, emission reduction through physical or chemical treatments and dilution through ventilation and air purification. While most solutions involve dilution through ventilation, increased interest in the scientific literature (Wolverton et al, 1989: Godish and Guindon, 1989) as well as in the popular media has been given to the use of plants to purify air in buildings . Most studies however, have been conducted in the laboratory (Levin J, 1992: Godish T and Guindon C, 1989) and are difficult to extrapolate to real life situations (Wolverton et al, 1989: Godish and Guindon, 1989).

Environmental exposure unit: a system to test anti-allergic treatment.

Reading this article will enable readers to recognize the Environmental Exposure Unit (EEU), its historic development and its current role as a system to test anti-allergic treatment; to recognize clinical relevance of this test system and its relationship with other pollen challenge methods of evaluation of anti-allergic medication; and, to recognize variables associated with standard clinical studies of anti-allergic medication. Readers will review four studies of antihistamines tested in the Environmental Exposure Unit, three studies on nasal corticosteroids, one on topical eye drops and one on immunotherapy conducted in the EEU. The EEU has been in operation since 1985 preceded by a prototype challenge system to assess respiratory effects of urea formaldehyde foam insulation. A number of studies on the onset of action and efficacy of different antihistamines and nasal corticosteroids as well as other treatments have been completed producing accurate and consistent results influenced to some extent by study designs. Studies of commonly used antihistamines and nasal corticosteroids are discussed in detail and represent several of the studies undertaken to date in the EEU. Controlled ragweed pollen exposure using the EEU has shown that some antihistamines demonstrate an onset of action within 30 minutes while others have taken up to 3 hours to produce significant effect. Nasal corticosteroids evidenced the onset of clinical improvement at 5 to 6 hours with significance over placebo between 6 and 12 hours depending on dose. The EEU is an effective pollen delivery system that accurately and consistently determines the onset of action and efficacy of anti-allergic treatment in large groups of subjects. It eliminates variables associated with various other methods of evaluation of these medications but does not supplant the need for such evaluations.

Risk assessment of low-level chemical exposures from consumer products under the U.S. Consumer Product Safety Commission chronic hazard guidelines.

The U.S. Consumer Product Safety Commission (CPSC) is an independent regulatory agency that was created in 1973. The CPSC has jurisdiction over more the 15,000 types of consumer products used in and around the home or by children, except items such as food, drugs, cosmetics, medical devices, pesticides, certain radioactive materials, products that emit radiation (e.g., microwave ovens), and automobiles. The CPSC has investigated many low-level exposures from consumer products, including formaldehyde emissions from urea-formaldehyde foam insulation and pressed wood products, CO and NO2 emmissions from combustion appliances, and dioxin in paper products. Many chemical hazards are addressed under the Federal Hazardous Substances Act (FHSA), which applies to acute and chronic health effects resulting from high- or low-level exposures. In 1992 the Commission issued guidelines for assessing chronic hazards under the FHSA, including carcinogenicity, neurotoxicity, reproductive/developmental toxicity, exposure, bioavailability, risk assessment, and acceptable risk. The chronic hazard guidelines describe a series of default assumptions, which are used in the absence of evidence to the contrary. However, the guidelines are intended to be sufficiently flexible to incorporate the latest scientific information. The use of alternative procedures is permissible, on a case-by-case basis, provided that the procedures used are scientifically defensible and supported by appropriate data. The application of the chronic hazard guidelines in assessing the risks from low-level exposures is discussed.

L'état, le citoyen et l'industrie: le cas de la MIUF

AbstractFrom 1977 to 1982, the Canadian government funded the installation of urea formaldehyde foam insulation (UFFI) in Canadian homes, then banned the product and subsequently paid homeowners who wished to have it removed. Then, in 1991, the case brought by the “victims” against the makers was found in Quebec Superior Court to be not proven. This article argues that the best way to understand this sequence of events is through a combination of decision theory, neo-institutionalism and postpluralism or neocorporatism.

Risk, Science, and Politics: Regulating Toxic Substances in Canada and the United States

Paying particular attention to how politicians and bureaucrats in the two countries deal with the scientific uncertainty that pervades environmental decision making, Harrison and Hoberg analyse case studies of seven controversial substances suspected of causing cancer in humans: the pesticides Alar and alachlor, urea-formaldehyde foam insulation, radon gas, dioxin, saccharin, and asbestos. They weigh the strengths and weaknesses of each country's approach according to five criteria: stringency and timeliness of the regulatory decision, balancing of risks and benefits by decision makers, opportunities for public participation, and the interpretation of science in regulatory decision making. The Canadian approach is exemplified by closed decision making, case-by-case review that relies heavily on expert judgement, and limited public debate about the scientific basis of regulatory decisions. In contrast, regulatory science in the United States is characterized by publication of lengthy rationales for regulatory decisions, reliance on standardized procedures for risk assessment, and controversy surrounding the interpretation of scientific evidence.

Maximum likelihood estimation in the multi-path change-point problem

Maximum likelihood estimators of the parameters of the distribu- tions before and after the change and the distribution of the time to change in the multi-path change-point problem are derived and shown to be consistent. The maximization of the likelihood can be carried out by using either the EM algorithm or results from mixture distributions. In fact, these two approaches give equivalent algorithms. Simulations to evaluate the performance of the maximum likelihood estimators under practical conditions, and two examples using data on highway fatalities in the United States, and on the health effects of urea formaldehyde foam insulation, are also provided.

Formaldehyde exposure and health status in households.

This report describes a case study concerned with acute and subacute health effects of formaldehyde in the indoor air, which is based on a large group of control houses and houses retroinsulated 4 to 5 years earlier with urea formaldehyde foam insulation (UFFI). Both groups underwent an environmental and health assessment on two occasions separated by an interval of 12 months, during which about one-half of the UFFI group performed remedial work on their houses. The results show that in the first survey of the study population, before remedial work, there was a moderate excess of many adverse health status indicators among the UFFI subset relative to the controls. This was associated with the presence of direct exposure-response relationships between formaldehyde levels in the UFFI houses and the prevalence of a number of symptoms. No comparable relationships were seen among the controls. At the second survey, performed following the removal of the UFFI, there was an appreciable reduction in the excess of most adverse health status indicators among the UFFI subjects. This improvement in health status among the UFFI removal subset was not associated with any significant diminution of formaldehyde exposures, although the previously observed exposure-response relationships had vanished. These observations imply that the findings obtained in the preremedial stage of the study cannot be explained by formaldehyde exposure alone.

Formaldehyde Exposure and Health Status in Households

This report describes a case study concerned with acute and subacute health effects of formaldehyde in the indoor air, which is based on a large group of control houses and houses retroinsulated 4 to 5 years earlier with urea formaldehyde foam insulation (UFFI). Both groups underwent an environmental and health assessment on two occasions separated by an interval of 12 months, during which about one-half of the UFFI group performed remedial work on their houses. The results show that in the first survey of the study population, before remedial work, there was a moderate excess of many adverse health status indicators among the UFFI subset relative to the controls. This was associated with the presence of direct exposure-response relationships between formaldehyde levels in the UFFI houses and the prevalence of a number of symptoms. No comparable relationships were seen among the controls. At the second survey, performed following the removal of the UFFI, there was an appreciable reduction in the excess of most adverse health status indicators among the UFFI subjects. This improvement in health status among the UFFI removal subset was not associated with any significant diminution of formaldehyde exposures, although the previously observed exposure-response relationships had vanished. These observations imply that the findings obtained in the preremedial stage of the study cannot be explained by formaldehyde exposure alone.

Urea formaldehyde insulating foams: a risk for health?

In 1983, the media brought out articies expressing serious concerns as to the use of Urea Formaldehyde Foam Insulation (UFFI). The emission of formaldehyde vapours within UFF insulated homes was held responsible for «serious health problems».

Hydrolysis and durability of urea formaldehyde foam insulation

Physical and chemical changes in urea formaldehyde foam insulation (UFFI) products after exposure to several temperature/relative humidity (RH) environments have been investigated in order to develop methods for assessing product durability in buildings. All products depolymerised, lost strength and emitted more formaldehyde gas when exposed to higher temperature/RH conditions. However, only products with high acidity exhibited dimensional instability, some exhibiting more than 30% linear shrinkage. Stable products were found to exhibit less than 4% linear shrinkage when exposed to 50°C and 96% RH for 28 days, and these conditions are recommended for durability assessment of UFFI products. Other properties of UFFI that should be specified to ensure long-term performance are (a) maximum acid value (ml of 0·1 m NaOH to neutralise 1 g of foam) of 0·1 for bulk dry set foam, (b) minimum dry density of 12 kg/m 3 and (c) maximum formaldehyde offgassing of 5 mg/g.

Reassessment of Formaldehyde Exposures in Homes Insulated with Urea-Formaldehyde Foam Insulation

Abstract The Connecticut Department of Health Services (DHS) responded to health complaints associated with urea-formaldehyde foam insulation (UFFI) between 1977 and 1983 with free air tests. As a result of investigation of health complaints in over 500 houses, UFFI was banned in Connecticut in 1981. However, a review of recent data obtained from private laboratories indicated that formaldehyde levels in the air of homes insulated with UFFI had dropped considerably since the time of installation and prompted this current study. This study was conducted to test the supposition that formaldehyde levels had dropped significantly since the late 1970s in homes that were insulated with UFFI during that time. Formaldehyde levels were measured in 30 homes, which had been tested by the DHS in the past, and were found to have had “high” levels. In addition, ten control non-UFFI homes were tested to establish background levels. The results of this study indicate that the formaldehyde levels in the “high” UFFI houses...

Effect of ambient environmental factors on indoor formaldehyde levels

The effect of ambient (outdoor) environmental parameters on formaldehyde levels in a temperature controlled urea-formaldehyde foam-insulated (UFFI) house and a mobile home was investigated over a 9-month period (July–March). Strong correlations between formaldehyde levels, solar radiation, ambient temperatures, inside/outside temperature differences and water vapor pressure were observed in the UFFI house and in the mobile home. Stepwise regression revealed a significant independent effect of solar radiation values on indoor formaldehyde levels in the UFFI house but not in the mobile home. Stepwise regression revealed no significant independent effect of the other environmental variables evaluated. The independent effect of solar radiation on formaldehyde levels in the UFFI house indicates that solar radiation can have a significant effect on formaldehyde concentrations, and this effect may explain anomolous results in whole house source interaction studies.

Visits to physicians before and after exposure to urea formaldehyde foam insulation.

The average number of visits to a physician made by a sample of 351 residents of homes insulated with urea formaldehyde foam insulation in Montreal in the one year period before exposure was 5.25, and in the year following 5.62, an increase of 7 per cent (odds ratio 1.07, 95% CI = 1.00, 1.15). The increase in visits in the post insulation year was limited to subjects who had the product installed in the winter (OR = 1.48, 95% CI = 1.18,1.85), and was not seen for study subjects who insulated their homes during other seasons of the year.

Comparison of health of occupants and characteristics of houses among control homes and homes insulated with urea formaldehyde foam: III. Health and house variables following remedial work

This report describes the second survey of a group of 762 control and urea formaldehyde foam insulated (UFFI) houses performed following an interval of 1 year, after about two-thirds of the UFFI households either had their UFFI removed or performed other UFFI-related remedial work. The UFFI subjects who lived in remedial houses showed a decline in indicators of impaired health status, to roughly equalize with those whose houses were not altered; they continued to show a small excess of adverse health indicators relative to the controls, but at a somewhat lower level than seen in the first survey. This improvement was not associated with changes in indoor levels of formaldehyde. Weak exposure-response relationships were observed between formaldehyde and upper and lower respiratory symptoms, but mainly in the combined UFFI and control populations; these are interpreted as representing the contribution of background levels of formaldehyde to the prevalence of respiratory complaints in the general population. The principal findings of this study were primarily based on subjective variables, but most could be directly validated by objective measurements in the UFFI and control subjects. The support for a causal relationship between impaired health and living in a UFFI house is considered to be moderately strong. However the demonstrated adverse effects are generally minor in nature.

Comparison of health of occupants and characteristics of houses among control homes and homes insulated with urea formaldehyde foam: II. Initial health and house variables and exposure-response relationships

A health survey was conducted on 1726 occupants of urea formaldehyde foam insulated (UFFI) houses and 720 residents of control homes. The occupants of the UFFI houses showed a modest excess of many symptoms relative to the controls. This excess of complaints was contributed mainly by the residents of households which were intending to have their UFFI removed and by onsets which followed the installation of UFFI. There were no associated abnormalities in nasal airway resistance, sense of smell, pulmonary function, or patch tests for allergy to formaldehyde. However, the UFFI subjects intending to have their UFFI removed demonstrated a small increase in nasal epithelial squamous metaplasia. The indoor formaldehyde levels of the UFFI houses were about 20% higher than in the controls, while the carbon dioxide levels were similar in both groups. The UFFI subjects showed positive relationships between level of formaldehyde exposure and the presence of a number of symptoms, which were largely dependent on a small group of formaldehyde values that were in excess of 0.12 ppm. A number of the exposure-response relationships were enhanced by UFFI. These results suggested that some adverse health effects of UFFI were explained by formaldehyde alone while others were related to the combined effects of formaldehyde and an additional UFFI-related factor(s) which was not identified.

Comparison of health of occupants and characteristics of houses among control homes and homes insulated with urea formaldehyde foam: I. Methodology

The methodology of a study in which a comparison is made of the health and house characteristics of the occupants of 231 control homes and 571 houses containing urea formaldehyde foam insulation (UFFI) is described. All homes and occupants were examined on two occasions separated by an interval of 12 months, during which two-thirds of the UFFI houses performed remedial work. The occupants were examined using a health questionnaire and a series of objective tests including pulmonary function, nasal airway resistance, sense of smell, nasal surface cytology, and patch tests. The houses were assessed using a questionnaire and measurements of indoor formaldehyde and carbon dioxide levels. No obvious bias has been identified in this survey with respect to the representativeness of the population studied, the classification of the UFFI and control groups, and the input from both the respondents and observers. The symptom responses made by individuals within the same households were not correlated. Quality control assessment of the objective health tests and formaldehyde sampling and assays demonstrated that these procedures remained stable over the two phases of the study, with the exception of the expected decrease in the pulmonary flow rates over 1 year and a small unexpected increase in the forced vital capacity and the forced expiratory volume in 1 s.

Residential Formaldehyde Control by Mechanical Ventilation

Abstract Studies of forced or mechanical ventilation applied for the control of residential formaldehyde levels were conducted in a urea-formaldehyde foam insulated (UFFI) house and in a mobile home. Air exchange rates were increased from base values (circa 0.2 ACH) to values in the range of 0.45–1.49 ACH by means of centrally installed heat-exchange ventilation systems. All studies were conducted under controlled temperature and humidity conditions. Formaldehyde levels were determined by the NIOSH chromatropic acid method. Ventilation rates in the UFFI house in the range of 0.48–1.49 ACH were observed to be associated with percentage formaldehyde decreases in the range of 55–79 percent. In the mobile home, ventilation rates in the range of 0.45–1.33 ACH were observed to be associated with percentage formaldehyde decreases in the range of 57–67 percent. Over the range of ventilation rates evaluated, forced ventilation appeared to be more effective in the UFFI house than in the mobile home. Though increase...

Fungi associated with urea-formaldehyde foam insulation in Canada.

Sixty-eight fungal taxa were identified from samples of urea-formaldehyde foam insulation taken from Canadian residences. Mesophilic taxa were predominant, with Penicillium spp., Trichoderma harzianum and Paecilomyces variotii observed most frequently. Extensive or conspicuous growth also was seen for Hormoconis resinae, Stachybotrys chartarum and Trichoderma viride in some samples. The potential for these fungi to have contributed to the adverse health effects reported in some homes containing UF-foam insulation is discussed.