bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Residual Stress on the J-R Curve of HY-100 Steel
Authors: Gallant AD , Bar-On I , Tuler FR
Published: March 2009

Fabrication processes in structural components can result in intended or inadvertent material behavior changes due to plastic deformation and residual stresses. In this study, the effect of a residual stress field caused by prior plastic deformation of a beam in four-point bending on the J-R curve of 12.7 mm (0.5 in.) thick specimens of HY-100 steel was investigated. Specimen blanks were deformed in four-point bending to two different levels of deflection prior to machining the starter notch. The resulting residual stress field in a companion test specimen was measured on side surfaces and through-the-thickness by a multiple exposure X-ray diffraction technique. J-testing was performed in three-point bending on undeformed specimens and the two deformed specimen sets using a modified multiple-specimen technique. A decrease in JQ and tearing modulus, T, with increasing specimen deflection was observed. The decrease in JQ was comparable to that observed previously in uniformly prestrained specimens.
The Application of the Multispecimen J-Integral Technique to Toughened Polymers
Authors: Huang DD
Published: March 2009

The multispecimen J-integral technique ASTM Test Method for JIc, a Measure of Fracture Toughness (E 813-87) has been applied to a series of rubber-toughened polymers to determine the generality of the method for polymeric materials. The experimental procedures produce results that are similar in form with those found in the metals and ceramics literature. However, many of the procedures involving data analysis require reexamination.

In this study, the effects of side grooves, ligament depths, and the relationship between critical initiation J and G values are examined. The use of side-grooved specimens for J testing is a viable way of experimentally verifying plane strain conditions. The ASTM E 813-87 recommendation for the allowable range of ligament depths appears to be inappropriate for toughened polymers. However, the recommendation of W/B = 2 as an experimental starting point is sensible. Finally, the JIc to Gc relationship was explored. In separate, nonstandard K tests involving large specimens, the initiation point, Gc, was defined at 2.5% crack growth. JIc, as calculated by the ASTM E 813-87 construction, was as much as 50% lower than this Gc value. However, when comparing critical J and G values for specific crack growths, good agreement between the two tests was obtained, provided the crack growth was small. Although the current JIc construction provides a conservative estimate of the Gc value, it is an open question whether the JIc value is appropriate for polymer design.
Fracture Toughness of Polycarbonate as Characterized by the J-Integral
Authors: Bernstein HL
Published: March 2009

Fracture tests have been conducted on polycarbonate in the elasto-plastic and fully plastic regimes. The fracture behavior was well characterized by the J-integral. The value of the J-integral at the initiation of crack growth, corresponding to JIc, was 2.1 kN/m (12.2 psi∙in.) for the 1981 ASTM Test Method for JIc, a Measure of Fracture Toughness (E 813-81), and 3.3 kN/m (19 psi∙in.) for the 1987 ASTM (E 813-87). It was found that the value of the J-integral at 2% crack growth, 4.4 kN/m (25 psi∙in.), corresponded well with values of KIc in the literature. It is suggested that the value of J at 2% crack growth may be a better parameter to characterize fracture than J at initiation. The value of the J-integral at popin or unstable fracture, 7.3 kN/m (41 psi∙in.), was consistent for all the experiments. No effect of crack length or thickness was observed for any of these values of J. Two difficulties with the use of the 1987 standard were found. The first was that the data did not coincide with the blunting line. More crack growth was measured than predicted by the blunting line. The second was that a valid data point between the 1 and 1.5-mm offset lines could not be experimentally obtained because of the nature of crack growth in polycarbonate.
Modeling Human Exposure to Airborne Pesticides in Closed Environments
Authors: Kogan V , Gieseke JA
Published: March 2009

A computer program was developed for the assessment of human exposure to airborne pesticides in the work place, such as a greenhouse or a chemical production plant. The program considers various aspects of aerosol physics including accounting for sources, transport, deposition, and evolution of the size distribution of aerosol materials. In addition, it addresses phase transition phenomena and photolysis. It evaluates level of exposure to airborne particles based on arbitrary schedule of worker activities. Results of model calculations using the computer code show the importance of source strength, droplet size, air flow patterns, applicator activities and location, and atmospheric conditions.
Evaluation of the Carbo-Flo● Pesticide Waste Management System
Authors: Hall FR , Downer RA , Chapple AC
Published: March 2009

The CARBO-FLO● water effluent treatment process uses a simple flocculation and filtration system which requires no specialized personnel for its effective use. Treatment is carried out using pre-weighed/pre-packed materials designed to treat 1000 liters of diluted spray liquor. The flocculation and settlement process takes a minimum of 1 hour. Filtration through one coarse gravel and two fine carbon filters takes approximately 2 hours.

Water containing atrazine, alachlor and permethrin was processed through the specially designed SENTINEL● plant. These pesticides were chosen as they are widely used and represent a range of chemical groups. Trials using both single products and a three way mix were performed. Analysis of the treated water at different points in the system was carried out using gas chromatography. All treatments resulted in >99.9% of the pesticide being removed from the end water. Water thus treated can, at present, be recycled for subsequent use as rinse water or may be discharged into a soakaway. All solid waste from the process can be incinerated. The carbon filters can be regenerated. Some possible user problems with the flocculation process were encountered and investigated. Adequate dilution of the pesticide waste liquor was found to be essential for the process to be completely efficient.
Temperature-Activated Release of Trifluralin and Diazinon
Authors: Carter DH , Meyers PA , Greene CL
Published: March 2009

Landec Labs has been developing a family of polymers (Intelimer™) that when used in encapsulation, respond to a temperature change by releasing active ingredient (AI). Microcapsules made from these polymers containing selected pesticides have been developed which utilize this “off” and turn “on” property. Below the temperature of interest, the microcapsules have low release of the AI thereby protecting it from leaching and degradation. At the temperature of interest, the microcapsules have a higher release of the active ingredient. The change in release rate in response to temperature is unique to microcapsules made from Intelimer polymers and is not observed with commercial microcapsules. A variety of active ingredients including trifluralin and diazinon have been successfully microencapsulated using Intelimer polymers. Greenhouse and field studies indicate the microencapsulated trifluralin had reduced phytotoxicity to corn. In a cotton field trial, trifluralin microcapsules at a 0.55 kg AI/ha rate provided equivalent 90 day control of weeds to a 1.1 kg AI/ha treatment of Treflan 4EC™. Greenhouse results have demonstrated the temperature-activation characteristics with trifluralin and diazinon. The efficacy of diazinon capsules (made with Intelimer polymers) on corn root worm also will be discussed.
Emulsifiable Concentrate Formulations for Multiple Active Ingredients Using N-Alkylpyrrolidones
Authors: Narayanan KS , Chaudhuri RK
Published: March 2009

Higher N-alkyl pyrrolidones, a new and unique class of surface active solvents have been shown to be excellent for formulating a wide variety of agricultural active ingredients (a.i.) as emulsifiable concentrates (ECs). The proprietary solvent system we have developed for ECs consists of four components: 1. Water-soluble lower N-alkyl pyrrolidones, such as N-methyl pyrrolidone (AgsolEx™1), that are needed for high a.i. loading in the formulations. AgsolEx™1 is polar, has very high solvency and is biodegradable. 2. Water-insoluble higher N-alkyl pyrrolidones, such as N-octyl pyrrolidone (AgsolEx™8) and N-dodecyl pyrrolidone (AgsolEx™12) that eliminate crystal formation and stabilize the EC on dilution with water. These alkyl pyrrolidones are moderately polar, have surfactant and wetting properties, have low toxicity and are biodegradable. 3. Hydrophobic solvents, such as aromatic petroleum oils and long chain esters, help to improve the quality of the emulsion on dilution with water. 4. Nonylphenol ethyoxylated phosphate ester surfactants.

The active ingredients evaluated in our EC system included: atrazine, bendiocarb, carbaryl, dichlofluanid, diuron, metolachlor, pendimethalin, prodiamine, thidiazuron and triforine. Triangular co-ordinate plots were used to optimize the ternary solvent composition for a fixed weight ratio of active ingredients and surfactants. By using this solvent optimization technique, a variety of active ingredients having different biological spectra have been combined into a single EC formulation.

A working model is proposed that explains the universality of the system and its high stability on dilution with water.
Improvements in Dry Flowable Tank Mix Compatibility
Authors: Collins HM , Munie LA
Published: March 2009

Tank mix compatibility has frequently been a problem for dry flowable formulations. Compatibility with either co-pesticides or liquid fertilizer has been poor in the past resulting in flocculation or sedimentation. Traditional lignosulfonate and naphthalene condensate surfactants used in dry flowables appear to compound these compatibility problems. Developments in surfactant technology have served to improve the tank mix compatibility in dry flowables.

A new class of dry flowable surfactants is discussed and compared to the traditional surfactants. The compatibilities of many dry flowables are extensively evaluated. The new surfactants were found to improve tank mix compatibility without the loss of suspensibility in water.
The Expedite® Pesticide Application System; A More Efficient, Safer Backpack Pesticide Application System
Authors: Wright DR
Published: March 2009

The Expedite® Pesticide Application System is a unique backpack application system. The system is unique in that the packaging, formulation and applicator are an integrated system. This closed, ready-to-use system gives a pesticide applicator a way in which to apply pesticides that reduces exposure to chemicals through direct handling of the pesticide[1]. The light weight, accurate delivery, Controlled Droplet Application (CDA) spray system allows for a more efficient way to apply pesticides[2] [3].
Effect of Wear on Spray Characteristics of Fan Pattern Nozzles Made from Different Materials
Authors: Ozkan HE , Reichard DL , Ackerman KD , Sweeney JS
Published: March 2009

Spray nozzles are important in metering the liquid, atomizing, and controlling the distribution of spray over the spray swath. The effects of nozzle wear on flow rates, spray patterns, and droplet size spectrums delivered by fan pattern nozzles made from different materials were investigated. The relative wear rates of nozzle materials varied greatly with different times of use. At the end of test periods, hardened stainless steel was the most resistant to wear, followed in order of decreasing resistance to wear by stainless steel, plastic, nylon and brass. Nozzles with lower capacities wore at faster rates than nozzles with higher capacities. An automated computerized weighing system was developed to rapidly evaluate the effect of nozzle orifice wear on the spray deposit distribution. The results indicate that there was little difference between the spray deposit distributions of new and worn fan nozzles. The width of the spray pattern remained nearly constant but the worn nozzles delivered greater volumes of liquid in the centers of the patterns. Generally there was little difference in droplet size distributions between new and worn nozzles.
Use of Surface Relationship Models to Predict the Spreading of Nonaqueous Droplets on Johnsongrass
Authors: Chambers GV , Bulawa MC , McWhorter CG , Hanks JE
Published: March 2009

A renewed interest in improving the application of chemical pesticides has prompted additional application research on utilizing spray adjuvants or carrier systems for enhancing ground or aerial applications. This application research is producing findings on the potential of nonaqueous application systems as well as research leads for improving pesticide formulations. Nonaqueous application systems provide greater surface coverage than aqueous or emulsion systems. While the total spray volume for nonaqueous carriers was substantially less in field comparisons, efficacy was better. In comparisons of nonaqueous carriers, mineral oil was superior to vegetable oils (soybean, cottonseed) in weed control. A number of factors can affect the surface coverage of pesticide formulations. This paper evaluates factors for relationship to surface coverage on grasses, including: (1) the surface chemistry of the carrier/adjuvant and (2) leaf chemistry of grasses. Other measurements of spreadability on inert surfaces were compared to the measurement of coverages on johnsongrass leaves.
Some Factors Affecting Herbicidal Activity of Glyphosate in Relation to Adjuvants and Droplet Size
Authors: Prasad R
Published: March 2009

The influence of four adjuvants (Ethokem, Multifilm, Regulaid and Tween-20) and four spray-droplet sizes (159, 332, 447, 575 μm) on efficacy and crop tolerance with a glyphosate formulation were investigated for white birch [Betula papyrifera L.] and white spruce [Picea glauca (Moench) Voss] under greenhouse and laboratory conditions. It was found that some adjuvants (Ethokem, and Tween-20) enhanced the effectiveness of glyphosate sprays without damaging the crop (white spruce) species. Tests with 14C-glyphosate showed greater penetration and translocation by birch leaves when an adjuvant was used. Of the four droplet sizes tested, small droplets (159 μm) of glyphosate were more phytotoxic than large drops (575 μm). The implication of these findings in relation to herbicidal action of glyphosate on forestry species is discussed.
Air Toxics Monitoring Plan for the Denver Metropolitan Area—Integrated Environmental Management Project
Authors: Komp M , Svoboda L , Frey S
Published: March 2009

The air toxics monitoring plan for the metropolitan Denver Integrated Environmental Management Project (IEMP) sponsored by the U.S. Environmental Protection Agency (EPA) describes the monitoring program to be used during the project to collect data on ambient levels of toxic compounds in the air. The plan describes the objectives, monitoring approach, and sampling methods and analyses of the program. Aspects of the analyses described in the plan include the determination of the exposure of the population to the toxic concentrations found during the monitoring program and the apportionment of these toxic compounds to sources in the metropolitan area. The data to be collected will be of value not only in Denver, where a comprehensive air toxic database will be completed, but to the ongoing national effort by EPA to assess the magnitude of the air toxics problem in urban areas.
Defining Toxics Problems at the State Level—The State of California's Monitoring Program
Authors: Crowe D
Published: March 2009

The State of California's Air Resources Board has implemented a network for monitoring the levels of potentially toxic air contaminants (TACs) at 20 population centers throughout the state. The monitoring is designed to support a program to identify the presence of any TACs that are at levels which would require the adoption of emission control regulations. The network monitors concentrations of eleven organic gases and eight particulate metals. Pesticides are also monitored at various locations on an intermittent basis.

A substantial amount of work has been accomplished in developing and documenting TAC sampling and analysis methods, acquiring authoritative calibration standards, and implementing data quality assessment procedures. However, improvements are still needed in such areas as automating TAC analyzers, lowering the detection limits for TAC analysis methods, conducting interlaboratory validations of TAC analytical methods, producing National Bureau of Standards certified calibration gases at ambient TAC levels, and improving quality assurance/quality control documentation.
Program Strategies for Standards Development for Hazardous Waste Incineration
Authors: von Lehmden DJ
Published: March 2009

This paper discusses program strategies of the U.S. Environmental Protection Agency's Environmental Monitoring Systems Laboratory; the strategies under consideration are strategies for standards development for hazardous waste incineration. The paper discusses the goals of the program, the selection of compounds for standards, the selection of compound concentrations for standards, the stability of standards, the traceability of analyses to NBS gas standards, a comparison of the compounds selected versus the current need, and the availability of the standards.
Auditing Hazardous Waste Incineration—EPA Program
Authors: Jayanty RKM , Allen JM , Sokol CK , von Lehmden DJ
Published: March 2009

Audit standards consisting of volatile and semivolatile organics have been established by the EPA to be provided to federal, state, and local agencies or their contractors for use in performance audits to assess the accuracy of measurement methods used during hazardous waste trial burns. The volatile organic audit standards currently total 29 gaseous organics in 5, 6, 7, 9, and 18-component mixtures at part-per-billion (ppb) levels (1 to 10 000 ppb) in compressed gas cylinders in a balance gas of nitrogen. The semivolatile organic audit standards currently total six organics which are spiked onto XAD-2 cartridges for auditing analysis procedures.

Studies of all organic standards have been performed to determine the stability of the compounds and the feasibility of using them as performance audit materials. Results as of July 1987 indicated that all of the selected organic compounds are adequately stable for use as reliable audit materials.

Performance audits have been conducted with the audit materials to assess the accuracy of the measurement methods. To date, 160 performance audits have been initiated with the ppb-level audit gases. The audit results obtained with audit gases during hazardous waste trial burn tests were generally within ±50% of the audit concentrations. A limited number of audit results have been obtained with spiked XAD-2 cartridges, and the results have generally been within ±35% of the audit concentrations.
Mobile Field Monitoring of Volatile Organics and Toxic Air Pollutants Using a Mobile Tandem Mass Spectrometer System
Authors: Shushan BI , DeBrou G , Mo SH , Webster W
Published: March 2009

The recent marriage of tandem mass spectrometry (MS/MS) to mobile trace atmospheric gas analyzer (TAGA) technology has resulted in an analytical system capable of real-time direct air analysis for toxic air pollutants (TAP), volatile organic compounds (VOC), and odor compounds at concentrations as low as a few parts per trillion. This direct analytical approach obviates problems associated with conventional trapping methods. The latest design of a mobile MS/MS laboratory comprises a customized 9-m (30-ft) transit motor coach configured with a TAGA 6000EM MS/MS system and ancillary equipment. This paper discusses the incorporation of a sorbent cartridge purge unit into the TAGA system to assist in rapidly distinguishing between isomeric compounds (for example, ethylbenzene and xylene) using gas chromatography (GC/MS/MS. This paper also describes combining real-time TAP analysis with meteorological data to rapidly and accurately characterize plume profiles and emission frequencies. The mobility of the TAGA detector permitted the precise location of point source and fugitive emissions. Examples are provided for industrial emissions of methyl ethyl ketone and dimethyl sulfide. A simple method of on-site calibration was used, based upon headspace syringe injection. Under interactive computer control, calibration constants were determined in about 5 min per compound within the ambient air matrix. Other recent software developments are discussed, including the ability to simultaneously monitor up to 128 different compounds with real-time output in concentration units.
Characterization of a Low-Concentration-Level Acid Gas Calibration System: Sulfur Dioxide in Air, from 100 to 1 ppb
Authors: Dorko WD , Cai Z-T
Published: March 2009

The Acid Precipitation Act of 1980 called for a comprehensive ten-year program to identify the causes and sources of wet and dry acid deposition, to evaluate their effects, and, on the basis of the findings, to minimize or eliminate their sources where possible. The U.S. Environmental Protection Agency (EPA) is involved with several aspects of the overall interagency National Acid Precipitation Assessment Plan, including field monitoring and quality assurance. One of the major precursors of acid deposition is the gas sulfur dioxide (SO2). The purpose of the project described in this paper was to provide the EPA with standards or predictable test atmospheres of SO2 in air in the parts-per-billion range. Since the amount of calibration gas required was great, it was not feasible to prepare the required mixtures in cylinders, characterize them, and supply them to the EPA. To overcome this limitation, dynamic dilution was chosen as a method of supplying the required mixtures. Gas cylinder mixtures of higher concentrations of SO2 were characterized with respect to concentration and stability over time. These mixtures were used as inputs to the dilution system and blended with large amounts of air to produce SO2 mixtures of known lower concentration. The analysis of the high-concentration cylinder mixtures is described, along with the characterization and evaluation of the components of the dilution system and the dilution system as a whole.
Analysis of Low-Concentration-Level Gaseous Sulfur Compounds in the Atmosphere
Authors: Goldan PD
Published: March 2009

Intentional sulfur doping of the flame photometric detector results in a quasilinear response with a linear dynamic range of ∼100, a significantly reduced detection limit of ∼3 pg of sulfur, and a graphic display of interferences caused by response quenching. The use of Teflon for all sample lines and valves is shown to result in significantly smaller analyte losses for several important volatile sulfur species including SO2, CH3SCH3 [dimethyl sulfide (DMS)], and H2S. Ozone interference is shown to be a major problem in the quantitation of ambient levels of DMS using both solid sorbant and cryogenic enrichment techniques. The relative merits of several ozone removal procedures are discussed.
Measurement of HCl in Flue Gas by Infrared Spectroscopy with the Spectran 677 Infrared HCl Monitoring System
Authors: Breton H
Published: March 2009

According to the Federal Immissions Control Law, most waste incineration plants in the Federal Republic of Germany are equipped with a continuously operating monitoring device to control hydrochloric acid (HCl) emissions. The Spectran 677 infrared HCl-emission monitoring system of the Bodenseewerk Gerätetechnik GmbH, a long-path gas cell nondispersive infrared (NDIR) photometer that has been on the market since 1979, is described. The system is designed for HCl measurement after gas cleaning systems. The sampling system can also be modified for measuring HCl after dry scrubbers or after wet scrubbers. Field experiences are reported.
Tracer Gas Measurement Systems Compared in a Multifamily Building
Authors: Harrje DT , Dietz RN , Sherman M , Bohac DL , D'Ottavio TW , Dickerhoff DJ
Published: March 2009

The more complex building poses additional challenges to air infiltration measurement, especially in the case of multiple zones and rooms. Today's technology has provided us with a number of measurement choices which include the constant concentration single-tracer gas system, multitracer gas systems using the mass spectrometer, and perfluorocarbon multitracer systems both passive and active. This paper compares simultaneous field measurements in a Princeton-area multifamily building using each of these tracer gas-based air infiltration systems. Personnel from Princeton University, Lawrence Berkeley Laboratory, and Brookhaven National Laboratory were involved in the air infiltration measurement studies. Air infiltration rates in the various zones in each building are compared as well as the ease of implementation of the various approaches in these comprehensive measurements. Sources of errors using the various techniques are discussed.
A Numerical Investigation of the Constant Tracer Flow Technique
Authors: Lagus PL , Lie K-H
Published: March 2009

One of the techniques to be included in the upcoming revision of ASTM Standard E 741 is the so-called constant flow technique. This technique is effected by injecting tracer into a room or structure at a constant rate and measuring the resulting tracer concentration. For steady-state conditions, this resulting concentration can be interpreted in terms of an equivalent air leakage rate, assuming the source injection rate is known. An increasingly popular variant of this technique entails the use of passive injectors and samplers to obtain an estimate of long-term average air leakage rate.

We have undertaken an examination of numerical solutions to the first-order differential equation governing the concentration. To simplify our considerations, all calculations are based on a single well-mixed zone. Instantaneous and time average concentration histories are generated using measured air exchange data. These histories are then examined for their utility in predicting actual air leakage rates.

The passive long-term average technique appears to underpredict the actual air leakage rate for the limited data considered. Values of air leakage inferred from instantaneous measurements are also provided for comparison with actual air leakage rates.
Measuring Airflow Rates with Pulse Tracer Techniques
Authors: Persily AK , Axley J
Published: March 2009

New tracer gas techniques for measuring airflow rates in HVAC ducts and buildings airflow systems are described. These pulse tracer techniques are based upon the application of integral mass balance equations to the tracer gas concentration response of an airflow system to pulse injections of tracer. For building airflow systems, or portions of them, the airflow system is first idealized by an appropriate multi-zone model, pulse injections of tracer are applied to each zone independently, and the concentration response of each of the zones is measured. The multi-zone integral mass balance equations are formed and solved to determine the airflow rates between the zones. The airflows that are determined and the accuracy of these determinations are dependent not only upon the air exchange characteristics of the building, but also on the appropriateness of the system idealization employed.

This paper presents the theoretical basis of the pulse techniques for measuring airflows in ducts, and for studying single-zone and multi-zone building airflow systems. Procedures for formulating appropriate multi-zone idealizations of building airflow systems are described and practical details of pulse testing outlined. A series of field studies are reviewed, providing examples of procedures used to formulate system idealizations, experimental techniques employed to conduct the tests, and airflow rate measurement results.
The User's Influence on Air Change
Authors: Kvisgaard B , Collet PF
Published: March 2009

Of the various parameters deciding the air change in a building, the influence of wind and the stack effect have in particular been focused on. Concurrently, with the increase in quality of buildings and the tightening of existing buildings, the influence of the climatic parameters is reduced, and other parameters gain a greater influence on the air change. One of the parameters having a great influence on the air change in tight buildings are the users. The air change rate is greatly influenced by the users not only in naturally ventilated buildings, but also in mechanically ventilated buildings.

On the basis of continuous measurement of the air change in 28 dwellings, the proportion between the total air change (air change in house with occupants) and the basic air change (air change in a sealed house) is discussed. The air change in each of the dwellings has been measured for a period of about one week during occupancy. The measuring principle applied is the method with constant concentration of tracer gas. The measuring equipment utilized is computerized and capable of measuring in up to ten separate rooms for periods of more than one week without supervision.

The main conclusion of the measurement was that, even though the average air change rate for occupied dwellings is higher than 0.5 times/h (which is normally recommended in Denmark), some 20% of the dwellings have an air change rate so low that indoor climate problems may easily arise. Only a small percentage of the dwellings have ventilation systems that can be adjusted to provide the recommended rate of air change. The mechanical ventilation system usually gives too high a rate of air change, while the natural ventilation system usually provides too low a rate.
Comparison of Methods for the Measurement of Air Change Rates and Interzonal Airflows in Two Test Residences
Authors: Fortmann RC , Nagda NL , Rector HE
Published: March 2009

Four different but complementary methods—the tracer gas dilution method, single-tracer constant concentration, passive perfluorocarbon tracers (constant release), and constant release of multiple halocarbon tracers with semicontinuous analysis—were used to obtain detailed information on air exchange and interzonal airflow rates in the two GEOMET bilevel research houses. The four methods yielded comparable measurements of single-zone (whole-house) air exchange rates. Constant concentration tracer gas, perfluorocarbon tracer, and multiple halocarbon tracer measurements yielded comparable measurements of upstairs and downstairs air infiltration rates; downstairs infiltration rates were as much as seven times higher than upstairs. The constant-concentration method also provided detailed information on room-specific infiltration rates. Perfluorocarbon tracer (PFT) measurements of airflow rates between conditioned zones, the attic, and garage demonstrated the effectiveness of house-tightening retrofit procedures to reduce airflows to the unconditioned airspaces. Perfluorocarbon and halocarbon measurements of week-long, time-averaged interzonal airflow rates were comparable, but the halocarbon system showed that hourly interzonal airflow rates could be as much as an order of magnitude higher than the week-long average.
Results of a Pre-Field Measurement Program Fan Pressurization Comparative Test
Authors: Hadley DL
Published: March 2009

The Northwest Residential Infiltration Survey (NORIS) was a field study conducted in the Pacific Northwest to determine air leakage rates and infiltration characteristics of electrically heated, single-family, detached residences. Air leakage rates were measured using fan pressurization (blower door) techniques. The results of the blower door tests were used to estimate the natural building air infiltration rates.

A detailed set of measurement protocols based on the ASTM Standard Method for Determining Air Leakage Rate by Fan Pressurization Test (E 779-87) was developed prior to implementing the field testing. The measurement protocols were tested on two residences during a training workshop by five independent blower door testing technicians. The objectives of this workshop were: (1) to instruct the technicians on the specifics of the NORIS protocols in order to develop consistency in measurement among the technicians; (2) to evaluate the ability of the technicians and their respective blower doors to measure the leakage area of an orifice plate; and (3) to compare the results of depressurization and pressurization tests.

This paper will review briefly the field protocols used during the full field measurement program and present a detailed comparison of the results of the blower door tests conducted during the workshop.
The Effects of Wind on Residential Building Leakage Measurements
Authors: Modera MP , Wilson DJ
Published: March 2009

Over the past ten years, the measurement of the airtightness of single-family building envelopes has made the transition from laboratory research tool to practitioner's (home energy auditor's) tool. Along with this transition have come ASTM and CGSB standards for fan pressurization measurements, and an ASHRAE standard for single-family building airtightness levels. Two major sources of uncertainty identified for fan pressurization measurements of effective leakage area (the air leakage parameter specified in the ASTM and ASHRAE standards) were the statistical uncertainty associated with extrapolating fan pressurization measurements down to 4 Pa and the individual flow and pressure uncertainties induced by the wind and by instrumentation inaccuracies. This report analyzes the effects of wind on fan pressurization measurements and describes a series of experiments performed to examine a methodology that combines two techniques for reducing these effects. The methodology for reducing the effects of wind on fan pressurization measurements, which employs four-surface pressure averaging and time averaging of pressure and flow data, is examined using multiple fan pressurization measurements at a single site. The results of these experiments are compared with a similar experimental examination of the standard ASTM procedure under calm conditions. It is shown that the combined surface-averaging/time-averaging technique has significantly lower scatter at calm conditions (3 versus 6.5%), and that the scatter remains below 11% up to a windspeed of 5 m/s. Another significant result is that surface pressure averaging always causes a negative bias in the leakage area measured at high windspeeds. Despite this bias, it is concluded that surface-pressure averaging generally should provide better leakage area measurements compared to using single-pressure-tap measurements.
Fan Door Testing on Crawl Space Buildings
Authors: Brennan T , Pyle B , Williamson A , Balzer F , Osborne M
Published: March 2009

In order to learn something about the leakage characteristics of crawl spaces, a small-scale investigation was made using fan doors on nine buildings in Tennessee. This effort was part of a larger project to study the control of indoor radon levels in crawl space houses. The goal was to gain insight into the overall leakiness of crawl spaces and the leakage between the crawl spaces and the living spaces.

The investigation made first order estimates of the effective leakage areas (ELA) of the crawl spaces and the floor areas between them. It was discovered that, even with passive vents closed, crawl spaces are quite leaky compared to the building shell they support, and that the leakage area between the unconditioned crawl spaces and the conditioned upper part of the building were also large.
Air Leakage Measurements in Dwellings in Turkey
Authors: Tanribilir AH , Oskay R , Yener C
Published: March 2009

It has been necessary to check air leakage in dwellings due to complaints about thermal comfort and ever-increasing heating expenses. Airtightness of 18 rooms and air infiltration rate's of 34 rooms were measured using two blower doors and decaying tracer gas technique with nitrous oxide (N2O). Due to their availability, Canadian and ASTM standards were used for measurement. One of the blower doors was designed and constructed in Turkey. The test rooms were selected from new, unoccupied multistory apartment buildings and two-or three-story dwellings. Airtightness of the rooms was about 2.64 to 20.54 air changes per hour (ACH) at 50 Pa indoor-outdoor air pressure difference, while air infiltration rates were in the range of 0.16 to 1.99 ACH. To compare this with test results obtained abroad and with Turkish standards, normalized air leakage areas and air permeabilities of windows were also calculated from the results of airtightness experiments. They were found to be in the range of 0.57 to 24.45 cm2/m2 and 1.7 to 4.5 dm3/(s.m), respectively, at 10 Pa indoor-outdoor air pressure difference.
Investigation of a Fan-Pressurization Technique for Measuring Interzonal Air Leakage
Authors: Modera MP , Herrlin MK
Published: March 2009

Although the prediction of airflow through single-zone buildings has improved significantly during the past ten years, the more complex problem of predicting airflows in a multizone building has seen relatively little progress. One impediment to the solution of this problem has been the lack of reliable measurements of the flow resistances between the zones of such a building. This report analyzes a fan-pressurization technique for measuring the interzonal leakage (inverse flow resistance) in a multi-zone building. The technique involves two blower doors, one in each of the two zones between which the leakage is being measured. The evaluation of the technique is based upon simulations using MOVECOMP, a multizone infiltration and ventilation simulation program, which is used to determine what data would be recorded when using the procedure in a multifamily building under typical wind conditions. These simulations indicate that wind-induced uncertainties in the determined leakage parameters do not exceed 10% for wind speeds lower than 5 m/s. By performing additional simulations, the effects of wind conditions, building location, and measurement protocol on the uncertainties in the measured leakage parameters are examined in detail. These examinations highlight the importance of using an appropriate reference for the pressure difference across the primary-zone envelope.
Airtightness Survey of Row Houses in Calgary, Alberta
Authors: Love JA
Published: March 2009

While many reports are available on the airtightness of detached dwellings, little information is available on multifamily housing. In this study, airtightness characteristics of 42 row dwellings from nine housing complexes were obtained by depressurization [CGSB “Determination of Airtightness of Buildings by the Fan Depressurization Method” (CAN2-149.10)]. For 24 of the houses, airtightness was also determined with party wall leakage offset by simultaneous depressurization of dwellings adjacent to the test unit. The houses were built between 1965 and 1982 using wood-frame exterior wall construction; airtightness characteristics of exterior envelopes were found to be similar to those of detached dwellings of the same age and envelope construction. Airtightness characteristics of party walls were found to be similar to those of the exterior envelope.
Airtightness Measurements in Two UK Office Buildings
Authors: Perera MDAES , Stephen RK , Tull RG
Published: March 2009

A major factor in the ventilation of buildings is the leakiness of the building envelope. In housing, it has been possible for some time to measure leakiness quickly and easily by using a fan (sealed in place of the front door) to pressure/depressurize the building. Until now, this has not been done in larger buildings either in the UK or elsewhere in Western Europe.

The Building Research Establishment (BRE) designed and built three fan units which can be used together to pressurize large nonresidential buildings. A novel feature of the pressurization rig is that the fans are powered from conventional 13-A ring mains. This is in contrast to the techniques used in North America of either using a building's mechanical ventilation system (not possible in the UK since most buildings are naturally ventilated) or a large, bulky, trailer-towed fan with its own generator.

Envelope leakage tests have been carried out in two medium-sized (approximately 5500 m3) office buildings. Pressure differences of well over the accepted target of 50 Pa between inside and outside were reached easily.

Results showed that one of these buildings, of conventional construction, was twice as leaky as those found (on average) in North America. The other, built specifically as a low-energy office at BRE, was found to be as tight as the North American buildings. BRE will carry out measurements in further buildings as an aid to understanding and developing air leakage control from the viewpoint of natural ventilation.
Methods for Measuring Air Leakage in High-Rise Apartments
Authors: Shaw C-Y , Gasparetto S , Reardon JT
Published: March 2009

The balanced fan depressurization method has been modified for application to high-rise apartment buildings in order to measure the overall air leakage and the wall air leakage of an apartment unit simultaneously. The method requires the use of two sets of fan pressurization apparatus. One is installed at the door of an apartment unit for measuring the air leakage rate of the exterior wall, and a much larger apparatus is installed at an exterior door of the building for measuring the overall air leakage rate. The pressures between the test unit and the adjacent units are balanced to minimize the air leakage through the party walls by adjusting the airflow of the larger apparatus and the door opening of the adjacent apartments. The method was successfully applied to two high-rise apartment towers before and after they were retrofitted to improve airtightness of the envelope. In addition, the tracer gas decay method was applied to the same buildings to obtain the infiltration rates of selected apartment units.

The methods used to measure the airtightness values and the air infiltration rates and the test results of the two apartment towers are discussed.
Simple Test Method for Evaluating Exterior Wall Airtightness of Tall Office Buildings
Authors: Hayakawa S , Togari S
Published: March 2009

C. Y. Show, D. M. Sander, and G. T. Tamura developed a test method to measure the air leakage characteristics of exterior walls of buildings that utilized an outdoor air supply system of ventilation and air handling, taking into account the influence of the stack effect. They applied this method to eight tall buildings in Ottawa, and results were reported.

However, windows and wall constructions in Japan are so different than those in Canada that those results cannot be used directly. To obtain our own data, the authors developed a simple test method that utilizes buoyancy caused by the stack effect instead of fans for pressurization. To open doors on the ground floor or the window at the bottom part of the building while the stack effect is operative is the same as pressurizing the whole building, and to open an exit door at the roof or the window at the upper part of the building is the same as decompressing the whole building.

This method was applied to three tall buildings of Sendai and Tokyo, whose walls were cast-in-place concrete (Building A), precast concrete panel (Building B), and metal panel (Building C). For the test results, infiltration rates through the exterior wall were estimated by approximate calculation. Of the three, it was found that Building A was the tightest and Building C was the loosest. This paper reports the results of the application for the simple test method we developed.
Air Infiltration and Ventilation Centre's Guide to Air Exchange Rate and Airtightness Measurement Techniques
Authors: Charlesworth PS
Published: March 2009

The provision of an adequate supply of uncontaminated air suitable for the needs of the occupants is an important aspect of building design and construction. Ventilation can be promoted by natural or artificial forces, and it is necessary to understand this process since it affects both the energy consumption and the internal environment of a building. Ventilation is a complex process which is influenced by a variety of constructional, behavioral, and environmental parameters.

Measurement techniques provide the fundamental means of acquiring a greater understanding of air infiltration and ventilation, in that they enable primary data to be obtained from existing structures. In recognition of the importance of measurement techniques, the Air Infiltration and Ventilation Centre (AIVC) has produced a document titled Air Exchange Rate and Airtightness Measurement Techniques—An Applications Guide.

The guide primarily examines the measurement of air change rate, interzonal airflow, and airtightness. The broad aims of this document are to indicate the variety of techniques which are available, to provide detailed information about several techniques, and to offer advice regarding the selection of techniques for particular applications. This paper describes the scope, structure, and content of this guide to air exchange rate and airtightness measurement techniques.
The Use of REMOTS® Imaging Technology for Disposal Site Selection and Monitoring
Authors: Rhoads DC , Germano JD
Published: March 2009

In situ sediment profile imaging was developed for the purpose of rapidly mapping thin layers of disposed dredged material (0.1 to 20 cm thick) and to document efficiently faunal recolonization and diagenesis of disposed sedimentary materials. This technique is called REMOTS® (Remote Ecological Monitoring of the Seafloor) and consists of sediment profile photography combined with computer image analysis.

REMOTS data sets have proven important for selecting containment or dispersive openwater disposal sites. Following disposai, REMOTS is used in combination with precision navigation and bathymetry to contour the mean thickness of disposed materials to 1-cm intervals of thickness. If capping is done, the thickness and continuity of the cap along the flanks of the mound are also determined with REMOTS. Accurate mass balance calculations require high-resolution mapping of thin-layered disposed materials, particularly on the flanks of deposits where layers are typically too thin to be resolved with acoustics.
The Use of Fiber Optic Sensors for In-Situ Chemical Measurements in the Ocean
Authors: Tokar JM , Pugh WL , Goswami K
Published: March 2009

New chemical measurement techniques are continually being developed to improve detection limits, accuracy, reliability, and to obtain data in situ or in real time. Recent work has been done in the development and application of fiber optics and fiber optic sensors (FOS) for the measurement of specific chemical parameters in saltwater systems. To date, FOS have shown great promise and seem destined to become an important contribution to our ability to predict water quality trends in marine and estuarine waters. The National Oceanic and Atmospheric Administration (NOAA) is supporting the development of FOS for measuring pH, carbon dioxide, and dissolved oxygen in marine waters. These and other FOS will be discussed with emphasis on sensor design, current research, ocean applications, and future direction.