Batt Insulation Research Articles

Transit-oriented development: A case study of exterior-to-interior noise control for buildings near transit and highway noise sources

A case study of acoustical design for mixed-used, transit-oriented development is presented. The project is two, six-story mixed-used residential buildings near a rapid transit station and heavily traveled elevated highway in the San Francisco Bay Area. The buildings are metal frame construction over concrete podiums. The California Building Code requires the building shell to be designed to provide interior noise from exterior noise sources not to exceed 45 dBA Ldn. Exterior noise due to trains and buses serving the transit station, and traffic on the elevated highway, required high sound attenuating windows and acoustically rated walls and roofs. Initially, none of the exterior wall assemblies included batt insulation in the stud cavities, only continuous rigid insulation behind the façade. Modeling was done to compare the exterior wall assemblies with and without batt insulation in the stud cavities combined with various window configurations. Estimates of the building shell transmission loss are presented along with a summary of noise control recommendations for building roof, windows, and doors.

Thermal Performance of Lightweight Steel Framed Facade Walls Using Thermal Break Strips and ETICS: A Parametric Study

The thermal performance of lightweight steel framed (LSF) facade walls depends on many factors, such as the steel studs, the batt insulation, the external thermal insulation composite systems (ETICS), and the sheathing layers. Moreover, the high thermal conductivity of steel could negatively affect their thermal performance due to the consequent thermal bridge effect. Furthermore, in LSF walls, the batt insulation is usually bridged by the steel studs. Thus, some analytical calculation procedures defined in standards (e.g., ISO 6946) are not valid, further complicating their thermal performance quantification. In this research, a parametric study to evaluate the thermal performance of facade LSF walls is presented. Seven relevant parameters are assessed, most of them related to the use of thermal break strips (TBS) and ETICS. The 2D numerical models used to predict the conductive R-values were experimentally validated, and their precision was successfully verified. As earlier found in a previous research work for partition LSF walls, it is also more effective for facades to increase the TBS thickness rather than their width, with the R-value increments being slightly smaller for facade LSF walls. These features were more pronounced for double TBS and for the smaller stud spacing (400 mm). The major thermal performance improvements were found when increasing the ETICS insulation thickness and decreasing their thermal conductivity.

Performance of a Mid-Size Net-Zero Energy Solar House

The University of Alabama at Birmingham (UAB) was one of 16 collegiate teams from around the world that participated in the U.S. Department of Energy Solar Decathlon 2017 competition. An interdisciplinary team of students from across the university was engaged in a 2-year long process to design and build a house that is powered completely by solar power. The house was equipped to run all the typical appliances of an average modern house at similar levels on a conventional power grid. The net-zero house was built and tested on the UAB campus. Considering Birmingham’s weather, a safe room was built to ensure the safety of occupants during events of extreme weather, such as a tornado. A ductless HVAC unit consisting of an inverter-type 3-speed outdoor unit supplied refrigerant to four high-wall indoor units providing the primary source of space conditioning. To achieve a model of efficiency and cost effectiveness, the house incorporated a heavily insulated envelope and precise glazing protection. The roof, floor framing and walls had R-30 batt and foam insulation. With a design informed by southern vernacular language, the building is oriented to maximize solar access and to use roof planes for shading the majority of the year. Peak power generation of the panels was recorded at 9.6 kW. The home has a centralized energy management system that can provide access to energy consumption data and allow control of lighting, appliances, and plug loads remotely. Energy modeling showed that the annual electricity consumption for heating and cooling with variation in wall types were 8470 to 11,661 kWh. For the month of October, it was calculated varying from 683 to 763 kWh, with varying air changes per hour from 0 to 1.5.

Effective standoff in standing seam roof systems

To study and quantify the effect of effective standoff in standing seam roof systems, a test program of twenty-five roof assemblies was performed with varying clip type, panel type, clip height, and batt insulation thickness; and the results are presented in this paper. The tests measured the overall rotational stiffness of the connection between the purlin and the panel as well as the relative stiffness of the clip-to-purlin and clip-to-panel connections. Utilizing the rotational stiffness data from the tests, the effective standoff of the purlin-to-panel connection is quantified for each standing seam configuration. General trends in the effective standoff are reported and recommendations for approximate effective standoff values for various panel-clip-seam configurations are provided. Additional recommendations for performing tests to determine the effective standoff of a standing seam system are also presented. For most of the test assemblies, effective standoff distance is close by the mid-height of the clip. For a system of floating clip with vertical rib panels, the flexibility in the purlin-clip connection is greater which means the effective standoff distance is reduced, approaching to the top flange of the purlin. On the other hand, for the tests where the seam was uncrimped, the stiffness of the clip-flange connection is reduced, resulting in a shift in the standoff distance towards the top of the clip. It is also observed that the inclusion of fiberglass batt insulation between the clip and the purlin had no perceptible effect on the stiffness of the purlin-clip connection and did not change the effective standoff.

Technical Performance Overview of Bio-Based Insulation Materials Compared to Expanded Polystyrene

The energy efficiency of buildings is well documented. However, to improve standards of energy efficiency, the embodied energy of materials included in the envelope is also increasing. Natural fibers like wood and hemp are used to make low environmental impact insulation products. Technical characterizations of five bio-based materials are described and compared to a common, traditional, synthetic-based insulation material, i.e., expanded polystyrene. The study tests the thermal conductivity and the vapor transmission performance, as well as the combustibility of the material. Achieving densities below 60 kg/m3, wood and hemp batt insulation products show thermal conductivity in the same range as expanded polystyrene (0.036 kW/mK). The vapor permeability depends on the geometry of the internal structure of the material. With long fibers are intertwined with interstices, vapor can diffuse and flow through the natural insulation up to three times more than with cellular synthetic (polymer) -based insulation. Having a short ignition times, natural insulation materials are highly combustible. On the other hand, they release a significantly lower amount of smoke and heat during combustion, making them safer than the expanded polystyrene. The behavior of a bio-based building envelopes needs to be assessed to understand the hygrothermal characteristics of these nontraditional materials which are currently being used in building systems.

Case Study – When A Roof is More Than a Roof

The repurposing of existing buildings is becoming more prevalent. But changing a buildings use is not without concern. A European Company purchased an existing warehouse located north of Chicago, Illinois, USA as the space filled their needs for the layout of their manufacturing equipment. Producing medical grade synthetic mesh requires interior temperatures of 90°F (32.2C) with a relative humidity of 90%. The roof of the facility was low-sloped trapezoidal standing seam metal roof system that was watertight in all types of precipitation: Rain, snow, ice. The insulation, below the roof panels and above the steel purlins, was vinyl face fiberglass batt laid over the structural steel bar joist and pinned by the metal roof panels. Shortly after manufacturing commenced, water build-up in the batt insulation during winter started and was so severe that the vinyl facing would belly downward and split the lap seams, which would release the water, soiling the 2m wide rolls of mesh that then did not meet medical standards and had to be discarded. This case study will review the issues that arose out of repurposing a warehouse to a manufacturing facility and what the solution to correct moisture related issues. Hutchinson Design Group, Ltd. of Barrington, Illinois, was retained to investigate the conditions, determine the causes and develop a corrective solution.

Mycotoxin Production by Stachybotrys chartarum on Water-Damaged Building Materials

The major question after a flooding event is whether to remove or remediate the building materials so that potentially harmful mold growth and their by-products cannot cause serious health problems for susceptible individuals. The purpose of this study was to determine the growth of Stachybotrys chartarum and corresponding production of macrocyclic trichothecenes on different components of a residential wall up to 65 days after a simulated flood event. Small-scale residential walls constructed of fiberglass batt insulation, oriented strandboard, gypsum wallboard, and lumber were destructively sampled at four time points. All four building materials contained notable levels of macrocyclic trichothecenes on all collection days. The highest concentrations of macrocyclic trichothecenes were on the paper siding of the gypsum wallboard, followed by the paper siding of the batt insulation and wood lumber. There was a significant increase in trichothecene concentration over time, particularly on the gypsum. The DNA concentrations of the mold were significantly higher on the batt insulation than on the wood products, and the mold concentrations also increased over time on the batt insulation and gypsum, but not on the wood products. It was concluded that if a flooding event should occur, the insulation and gypsum should be removed from the home and the remaining materials should be remediated.

POWER CONSUMPTION COMPARISON OF FIVE BUILDING ENVELOPES IN THE NORTHERN PRAIRIE CLIMATE OF MANITOBA

The energy efficiency of a building depends on building envelope performance. The results presented in this paper are the first of a long-term building envelope research project at the Alternative Village at the University of Manitoba in Winnipeg, Manitoba, Canada. Five test buildings were constructed using the following systems: two wood frames with fiberglass batt insulation and dense pack cellulose, one polyurethane structural insulated panels (PUR SIP), and two with the Stay in place PVC concrete form building system using 102mm and 204mm of concrete externally insulated with 102mm of expanded polystyrene foam. All of the buildings had a common foundation and roof system with a footprint of 23.8 m2. Blower door tests were conducted to determine air tightness. Each structure was heated with an electrical resistance heater and maintained at a constant internal temperature. The thermal gradient through the wall and power consumption were monitored. The study period discussed in this report represents the main heating season from October 2011 to April 2012 consisting of 209 days. Based on the power consumption, the PUR SIP consumed the least at 2498 kWh, while the 204 mm Stay in place PVC concrete form building used the most at 2898 kWh for the same time period. The thermal gradient through the cross section of the wood frame structures was compared through the cavity insulation and at the stud. It was found that the cellulose building provided better thermal resistance along the stud when compared to the fiberglass batt insulation.

Sheep's wool insulation: A sustainable alternative use for a renewable resource?

Material selection in manufacturing may be characterized as a series of trade-offs between characteristics, properties, environmental impacts, sustainability, availability, and economics. Societal concerns about the environmental impacts of construction practices and materials have been expressed through an increase in the demand, production and use of “green” building products. This, combined with a desire to integrate more bioproducts and natural and renewable resources into the construction industry, has extended to the production and promotion of insulation made from sheep's wool.Although substantial literature exists on the insulation properties and other benefits of wool, less is known about the economics and manufacturing processes of sheep's wool insulation at varying scales of production. This paper contributes to this field of enquiry through presentation of the preliminary results of a wool insulation manufacturing pilot project, in which the scale and economics of the production of sheep's wool insulation were considered. Processing techniques, the impact of sheep breed, yield, energy use, and manufacturing costs were also examined. The results of the pilot project indicate that, while sheep's wool insulation produced at a smaller, or artisanal scale shows some potential, scale of operation and volume of production need to be carefully considered in order to ensure long-term sustainability of the operation. Using the least expensive sheep's wool available for the manufacture of wool batt insulation (and thereby reducing production costs) did not, in this pilot study, have a negative impact on productivity or product performance. Diversion of this waste stream of currently less marketable, and consequently less valuable wool, into the production of a green building material may offer small but significant benefit to sheep producers and the broader agricultural community, as well as consumers.

Case Study of Mechanical Control of Condensation in Exterior Walls

Abstract An electronics manufacturing facility in Colorado was constructed with typical commercial steel framing containing fiberglass batt insulation with foil-facing as the vapor retarder. A large portion of the facility required constant positive space pressurization and an indoor relative humidity (RH) of 48 % RH at 21°C (70°F). Due to a lack of containment of the moist interior air, condensation formed in the exterior walls, in the roofing, on the window and door systems, and on the skylights of the facility, particularly along the north and east elevations of the building, which resulted in significant damage to the wall components and the inability of the HVAC system to remain properly balanced. The as-constructed exterior wall systems were evaluated for performance relative to the existing building mechanical system. It was determined that the as-designed and as-constructed exterior wall assemblies and components could not perform satisfactorily under the necessary indoor environmental requirements. Options were explored to improve the performance of the exterior wall assemblies and related details. Due to a number of constraints, it was decided that constructing new walls inside the as-constructed exterior walls and windows, thereby creating an “interstitial” space to separate the exterior walls from the interior building space for their full height and mechanically supplying warm, dry air to this interstitial space, was the desired method to correct the condensation problems that were occurring. These repairs have proven to be effective. This paper discusses the original design and construction, the method of evaluation of the condensation problems that occurred, and the design and results of the implemented repairs.

Evaluation of Intumescent Coatings for Shipboard Fire Protection

In response to several claims from Manufacturers that intumescent coatings could be used in place of fire insulation and provide equal protection to shipboard structures during a fire, U.S. Navy conducted an extensive investigation of several fire protective coatings for use aboard ship. These fire protective coatings included water and solvent based coatings, insulative coatings, and foams. The objective of this program was to identify passive fire protection (PFP) coatings for shipboard interior applications capable of meeting U.S. Navy (USN) fire resistance requirements (DRAFT MIL-PRF-XX 381) of 30 min rating with backside average temperature rise less than 139 C using UL-1709 fire curve (post flashover fire). This evaluation consisted of small scale fire, adhesion, and impact tests; intermediate scale room corner fire tests, and full scale fire tests conducted aboard ex-USS SHADWELL. The test results with steel substrate show that all candidate coatings failed to meet minimum U.S. Navy fire resistance criteria when used as stand-alone coatings. Furthermore, many coatings demonstrated poor adhesion, and fell off from the substrate during the fire test. These data have led the Navy to conclude that intumescent coatings tested in this study are not sufficient to protect shipboard spaces during a fire and are not equivalent when used alone as direct replacement for batt or blanket type fibrous fire insulation (mineral wool, StructoGard) installed aboard U.S. Navy ships. However, U.S. Navy smallscale fire tests have also demonstrated that some of the intumescent coatings, when applied over substrates such as Glass Reinforced Plastic (GRP), did reduce flame spread and smoke generation.

End-User Exposures to Synthetic Vitreous Fibers: II. Fabrication and Installation Fabrication of Commercial Products

This article summarizes the results of exposure monitoring conducted during the installation and fabrication of commercial synthetic vitreous fiber (SVF) products. Included in this investigation were fiberglass duct insulation and construction applications (duct board, duct liner, and duct wrap), pipe and vessel insulation, batt insulation for prefabricated homes, and general fiberglass products. Commercial mineral wool products sampled as a part of this investigation included ceiling tiles, building safing, and loose insulation for prefabricated homes. A total of 520 valid air samples were collected as a part of this investigation and were analyzed using gravimetric, phase contrast microscopy (PCM), or scanning electron microscopy (SEM). Airborne fiber-size distributions were also determined for a subset of samples collected for SEM analysis. As a result of the task-based sampling strategy used in this study, sample times reflect exposures over the time the person was actually engaged in SVF-related work activities, and exposure results are therefore presented as task-length averages (TLAs). Thirty-five total dust samples were collected as a part of this investigation, resulting in 14 TLAs ranging from 0.3 to 7.6 mg/m3. A total of 125 PCM-based TLAs were collected, with the mean TLA time for all product and occupation categories ranging from 277 to 443 minutes. The mean PCM-based TLAs for all product/occupations were below 1.0 f/cm3, ranging from 0.04 to 0.68 f/cm3. A total of 116 SEM TLAs were determined. Average SEM-based TLA concentrations were slightly lower than the PCM-based estimates and ranged from < 0.01 to 0.16 f/cm3

End-user exposures to synthetic vitreous fibers: II. Fabrication and installation fabrication of commercial products.

This article summarizes the results of exposure monitoring conducted during the installation and fabrication of commercial synthetic vitreous fiber (SVF) products. Included in this investigation were fiberglass duct insulation and construction applications (duct board, duct liner, and duct wrap), pipe and vessel insulation, batt insulation for prefabricated homes, and general fiberglass products. Commercial mineral wool products sampled as a part of this investigation included ceiling tiles, building safing, and loose insulation for prefabricated homes. A total of 520 valid air samples were collected as a part of this investigation and were analyzed using gravimetric, phase contrast microscopy (PCM), or scanning electron microscopy (SEM). Airborne fiber-size distributions were also determined for a subset of samples collected for SEM analysis. As a result of the task-based sampling strategy used in this study, sample times reflect exposures over the time the person was actually engaged in SVF-related work activities, and exposure results are therefore presented as task-length averages (TLAs). Thirty-five total dust samples were collected as a part of this investigation, resulting in 14 TLAs ranging from 0.3 to 7.6 mg/m3. A total of 125 PCM-based TLAs were collected, with the mean TLA time for all product and occupation categories ranging from 277 to 443 minutes. The mean PCM-based TLAs for all product/occupations were below 1.0 f/cm3, ranging from 0.04 to 0.68 f/cm3. A total of 116 SEM TLAs were determined. Average SEM-based TLA concentrations were slightly lower than the PCM-based estimates and ranged from <0.01 to 0.16 f/cm3. The geometric mean fiber diameters for commercial products and occupations sampled as a part of the investigation ranged from 0.8 microm to 1.9 microm. Geometric mean fiber length varied by a factor of approximately three, ranging from 9.5 microm to 29.5 microm.

Noise Reduction Retrofit on Historic Structures

Cost-effective noise reduction techniques for historic buildings can be accomplished affordably and without altering the structure's historic status. Techniques include adding sashes to existing historic windows, replacing windows with visually compatible acoustic units, and using jamb extensions to accommodate manufacturers' standard window units. Wood-truss roofs can be insulated from noise on the interior through the addition of a light-gauge metal framing support with alternating layers of gypsum board, plywood, and batt insulation. Ventilation solutions include a unique over-the-sill air intake system that functions as an acoustic baffle and visually spares a historic facade from random louver punch-throughs. Acoustically rated doors and vestibule construction address noise reduction at entry ways. At an example installation, sound levels were reduced by 12 dB, and speech interference levels were reduced by 18-23 dB. Continuous use is the best method for preservation of historic buildings. Noise redu...

Noise Reduction Retrofit on Historic Structures

Cost-effective noise reduction techniques for historic buildings can be accomplished affordably and without altering the structure's historic status. Techniques include adding sashes to existing historic windows, replacing windows with visually compatible acoustic units, and using jamb extensions to accommodate manufacturers' standard window units. Wood-truss roofs can be insulated from noise on the interior through the addition of a light-gauge metal framing support with alternating layers of gypsum board, plywood, and batt insulation. Ventilation solutions include a unique over-the-sill air intake system that functions as an acoustic baffle and visually spares a historic facade from random louver punch-throughs. Acoustically rated doors and vestibule construction address noise reduction at entry ways. At an example installation, sound levels were reduced by 12 dB, and speech interference levels were reduced by 18–23 dB. Continuous use is the best method for preservation of historic buildings. Noise reduction, sensibly applied, gives a historic structure occupational viability in the modern world.

Evaluation of a commercial, computer-operated heat flow meter apparatus

A Holometrix, Inc., R-Matic model R-41 Heat Flow Meter Apparatus (HFMA) is evaluated by measurements on homogeneous materials and anisotropic composite materials. The former class of materials includes: foams, calcium silicate boards, fiberglass batts, and loose-fill fiberglass. Materials in the latter class are polystyrene with gas-filled panels and batts with powder-filled evacuated panels. Thermal models of the anisotropic composite materials allow design of composite test specimens and help in the interpretation of test results by computation of apparent thermal conductivities (k). The HFMA includes a dedicated computer for test control, data acquisition, and data analysis. Thus, the computer helps obtain the conditions needed to conduct accurate and repeatable steady-state tests to meet ASTM C 518 with minimum operator involvement. The k values from this HFMA and three other HFMAs (model R-20 and R-21 units) exhibit imprecisions of 2.2% (two standard deviations) for specimens of foam insulation. Such performance requires proper calibrations of good quality heat flux transducers and use of correct thermocouple thermometry practices. For six lots of fiberglass batt insulation, this HFMA and a HFMA model R-21 yield k values as a function of density with two standard deviations of 4.5%. Test results from this HFMA for three specimens of loose-fill fiberglass insulation provide k values as a function of density with two standard deviations of 5.1%. Because these levels of imprecision (2.2%–5.1%) include material differences, they illustrate the limits of error of the model R-41 HFMA.

Characterization of thermal performance of fibrous insulations subject to a humid environment

The insulating capability of a typical Fiberglas insulation slab exposed to different types of environment on each side of the slab was evaluated, based on theory that takes into account heat conduction, natural convection, phase changes, and gas infiltration. The results are analyzed and combined with recent theoretical work to find useful heat transfer characteristics for each of the material studied. These included RA-24 insulation, high-density wool; R-11 Batt insulation, low-density wool; RA-22 insulation, low-density board; and roof deck insulation, high-density board. 5 refs.

The Effect of Compression on the Material R-Value of Fiberglass Batt Insulation

Fiberglass batt insulations intended for use in buildings are labeled with an R-value and a thickness at which the R-value is achieved. In some cases the insulation is installed in such a way that the label thickness is not achieved. The material R-value of fiberglass batts installed at less than full thickness will be less than the full-thickness R-value.

Effect of insulating sheathing on heat and moisture flow

Wood-frame walls with low and high water vapour permeance insulating sheathings were tested in a climate simulator with respect to moisture and thermal performance. Exfiltration of moist interior air through the walls was simulated by pumping moist air into wall cavities from the warm side of the climate simulator where the walls were tested. It was found that ventilation slots in extruded polystyrene sheathing did not improve the drying ability of the walls. Incomplete filling of wall cavities with glass-fibre batt insulation, the presence of ventilation slots, and temperature difference across the walls had, if at all, a very small effect on thermal performance. The ability of glass-fibre-board insulating sheathing to store water condensed from exfiltrating air was improved by installing the sheathing with the spun-bonded polyolefin membrane facing the cold side. Key words: exterior walls, insulating sheathing, air exfiltration, condensation, thermal resistance, workmanship.

Condensation in Attics: Are vapor barriers really the answer?

Calculations of water vapor flow through walls and ceilings are frequently based on the permeabilities of building material, and implicitly assume that most of the vapor transport takes place by diffusion. In order to determine the validity of this assumption, a model for vapor transfer between two spaces by diffusion and convection is first developed. Measurements in a number of houses reveal that, for normal construction practices in U.S. wood frame houses, the transfer of water vapor from living space to attic is almost entirely by air movement. “Kraft” paper “vapor barriers”, frequently attached to batt insulation, do not effectively hinder air (or moisture) flow into attics. Even after numerous cracks and openings in the attic floor, below the insulation, were plugged, significant air flow from living space to attic remained, and evidence of condensation of water vapor within the attic was observed. In new housing, a continuous sheet placed between the ceiling and the framing of the attic floor should effectively hinder air and moisture flow. In existing housing, where it may not be possible to install a continuous sheet under the attic insulation, adequate opening for ventilation with outside air should be provided to prevent moisture build-up and condensation.