Air Leakage Rate Research Articles

Experimental study on the penetration efficiency of fine aerosols in thin capillaries

Aerosol penetration efficiency is one of the most important parameters for the safety assessment of a containment shell or containers of radioactive materials. In this work, a practical procedure has been developed to study the penetration efficiency of fine aerosol particles (size < 300nm) through capillaries with bore sizes ranging from 5 to 20µm and lengths from 10mm to 80mm under pressure differences from 60 to 450kPa. The effects of the upstream aerosol concentration, capillary dimension, and pressure difference on the aerosol penetration were investigated, and the relationships between the aerosol penetration efficiency and the air leakage rate as well as the average flow velocity in the capillary were obtained. The results showed that the penetration efficiency of aerosols through a capillary was positively related to the pressure difference as well as the air leakage rate until reaching 100%. For a given air leakage rate, the aerosol penetration efficiency fluctuated within a relatively wide range due to the influence of the pressure difference and capillary dimensions. The aerosol penetration efficiency decreased significantly with increasing capillary length but was identical for capillaries of the same length but different bore sizes. The aerosol penetration efficiency in capillaries showed a better correlation with the average flow velocity than with the air leakage rate. For flow velocities below 5m/s, the aerosol penetration efficiency increased with the air velocity in the capillary, while for velocities above 5m/s, a constant level of approximately 80–100% was maintained.

Utility of Objective Chest Tube Management After Pulmonary Resection Using a Digital Drainage System

We sought to evaluate the clinical utility of chest tube management after pulmonary resection based on objective digital monitoring of pleural pressure and digital surveillance for air leaks. We prospectively recorded the perioperative data of 308 patients who underwent pulmonary resection between December 2013 and January 2016. We used information from a digital monitoring thoracic drainage system to measure peak air leakage during the first 24 hours after the operation, patterns of air leakage over the first 72 hours, and patterns of pleural pressure changes until the chest tubes were removed. There were 240 patients with lung cancer and 68 patients with other diseases. The operations included 49 wedge resections, 58 segmentectomies, and 201 lobectomies. A postoperative air leak was observed in 61 patients (20%). A prolonged air leak exceeding 20 mL/min lasting 5 days or more was observed in 18 patients (5.8%). Multivariate analysis of various perioperative factors showed forced expiratory volume in 1 second below 70%, patterns of air leakage, defined as exacerbating and remitting or without a trend toward improvement, and peak air leakage of 100 mL/min or more were significant positive predictors of prolonged air leak. Fluctuations in pleural pressure occurred justafter the air leakage rate decreased to less than 20mL/min. Digital monitoring of peak air leakage and patterns of air leakage were useful for predicting prolonged air leak after pulmonary resection. Information on the disappearance of air leak could be derived from the change in the rate of air leakage and from the increase in fluctuation of pleural pressure.

Airtightness of Light-Frame Wood Houses built in Daejeon and Chungnam Area

Among the energy consumption in building, the heating energy takes the largest part. Therefore, it is important to minimize the heat energy loss in building for the reduction of overall energy use in construction. The most important points for the minimization of energy loss in building are insulation and airtightness. Especially, in wood houses, airtightness is very important for energy saving as well as increase of durability. However, the researches on airtightness of wood buildings have been started recently and are very deficient especially in Korea. In this study, air leakage properties and airtightness performance were evaluated for light-frame wood houses built in Daejeon and Chungnam area. Total 7 houses were evaluated, among which four houses (Case 1 to Case 4) were in the construction stage before interior finish and the other three houses (Case 5 to Case 7) were after completion of construction work. The tests for airtightness were conducted by pressurization- depressurization method, and the factors included in the measurements includes air leakage rate at 50 Pa (CMH50), air change rate at 50 Pa (ACH50), equivalent leakage area (EqLA) and EqLA per floor area. As a result of this study, key air leakage points in wood houses were found to be the gaps between floor and wall, the holes for wiring and plumbing, the double glasses windows and the entrance doors. The average value of ACH50 for the houses after completion of construction work was 3.5 h-1 that was similar to Europe standard (3.0 h-1). ACH50 was proportional to EqLA per floor area but inversely proportional to the internal volume, the net floor area and the area of window.

Numerical Strategy for Forecasting the Leakage Rate of Inner Containments in Double-Wall Nuclear Reactor Buildings

In the context of life extension of nuclear reactor buildings while ensuring safety and regulatory requirements, a numerical strategy is proposed to compute and forecast the air leakage rate evolution of inner containments in double-wall reactor buildings under standard long-term operation. In order to reduce the numerical cost of such complex computations, the proposed strategy is based on a coarse but adapted mesh together with a chained weakly-coupled thermo-hydro-mechanical modeling. The total leakage rate is then computed with a specially-designed tridimensional finite element based on a non-linear thermal analogy. This methodology is used to model the behavior of the VeRCoRs mock-up, a simplified nuclear reactor building at scale 1:3, built and monitored by EDF. Results obtained until the first pre-operational pressurization test have been discussed in a dedicated benchmark organized by EDF. The proposed methodology provides delayed strains and leakage results in good agreement with available experimental data. A blind prolongation until the first decennial test of the mock-up is presented and analyzed.

Sustained versus intermittent lung inflation for resuscitation of preterm infants: a randomized controlled trial

Aim: To evaluate efficacy and safety of delivery room (DR) sustained lung inflation (SLI) in resuscitation of preterm neonates.Methods: Randomized Controlled Trial including 112 preterm infants randomized to either SLI (n = 57) using T-piece resuscitator [maximum three inflations with maximum pressure of 30 cmH2O for 15 s followed by continuous positive airway pressure (CPAP) of 5–7 cmH2O] or conventional bag/mask inflation (CBMI) (n = 55) using traditional self-inflating bag (maximum pressure of 40 cmH2O at a rate of 40–60 per min). Failure was defined as the need for DR or first 72 h intubation. Cord and 2-h post-resuscitation blood samples were collected to measure interleukin (IL)-1β and tumor necrosis factor-α levels before and after intervention.Results: SLI was associated with significantly higher success rate compared to CBMI [75.4 versus 54.5%; p = 0.017], lower need for DR intubation [5.3% versus 23.6%; (X2 = 7.7; p = 0.005)], higher 5-min-Apgar score (median 8 versus 7; p = 0.018), shorter duration on nasal-CPAP (p = 0.017), and non-significantly different air leak (7% versus 11%; p = 0.3) and bronchopulmonary dysplasia rates among survivors (2% versus 11%; p = 0.09). Post-resuscitation IL-1β plasma levels increased significantly in CBMI (p = 0.009) and not in SLI group.Conclusion: Delivery room SLI is more effective than intermittent bag and mask inflation for improving short-term respiratory outcome in preterm infants, without significant adverse effects.

CASE-STUDY ANALYSIS OF CONCRETE LARGE-PANEL APARTMENT BUILDING AT PRE- AND POST LOW-BUDGET ENERGY-RENOVATION

The paper presents a case study analysis of low-budget renovation of a typical concrete large-panel apartment building. Focus is on the measurements and analyses of energy consumption, indoor climate, CO2 concentration, air leakage rate, thermal transmittance of thermal bridges, and thermal transmittance of the building envelope before and after the renovation. Results indicate that the renovation project was generally successful, with delivered energy need de­creasing by 40% and heating energy need decreasing by 50%. However, some key problems need to be solved to achieve full energy efficiency potential of the renovation works. Those critical problems are the performance (thermal comfort, heat recovery) of ventilation systems, thermal bridges of external wall/window jamb and economic viability. Currently, a major renovation is not economically viable, therefore financial assistance to the apartment owners’ associations is required to encourage them to undertake major renovations.

In-Place Filter Tester Instrument for Nuclear Material Containers.

A portable instrument was developed to determine filter clogging and container leakage of in-place nuclear material storage canisters. This paper describes the development of an in-place filter tester for determining the "as found" condition of unopened canisters. The U.S. Department of Energy uses several thousand canisters for nuclear material storage, and air filters in the canister lids allow gases to escape while maintaining an equilibrated pressure without release of radioactive contamination. Diagnosing the filter condition and canister integrity is important for ensuring worker and public safety. Customized canister interfaces were developed for suction clamping (during tests) to two of the canister types in use at Los Alamos National Laboratory. Experimental leakage scenarios included: O-rings fouled with dust, cracked O-rings, and loose canister lids. The prototype tester has a measurement range for air leakage rates from 8.2 × 10 mL s up to 3.0 × 10 mL s. This is sufficient to measure a leak rate of 3.4 × 10 mL s, which is the Los Alamos helium leak criterion for post-drop tested canisters. The In-Place-Filter-Tester cannot measure to the lower value of the helium leak criterion for pre-drop tested canisters (1.0 × 10 mL s). However, helium leak testing requires canister disassembly, while the new in-place filter tester is able to assess the assembled condition of as-found and in-situ canisters.

Durability and Measurement Uncertainty of Airtightness in Extremely Airtight Dwellings

In this paper a series of leakage tests is presented on extremely airtight dwellings, studying the durability of the airtightness level and the measurement uncertainty involved. All houses subjected to testing are certificated passive houses, meaning the maximum air leakage rate upon completion was n50 < 0.6 h-1 air changes per hour at 50 Pa pressure difference.In the literature, repeatability and reproducibility issues have been discussed by several authors, along with influences of weather conditions. However, it remains unclear to what extent the available uncertainty intervals are relative or absolute. With the current tendency towards extremely low leakage levels and the introduction of airtightness requirements in building codes, the further exploration of this issue has become crucial.Four aspects concerning air leakage tests are examined: the repeatability and reproducibility of the fan pressurization results in extremely airtight houses, the impact of weather conditions on the measurement results, the impact of the age of the construction, and the reproducibility of the airtightness level in repeated construction of virtually identical houses. The latter is limited to short term effects since all dwellings (n = 15) were completed after 2010.The results show similar relative repeatability and reproducibility intervals to those found in the literature. The rather large effects of weather conditions reported in previous studies could not be reproduced. Normal wear and tear due to occupation of the dwelling proved to introduce substantial relative deterioration of the airtightness of the building shell (20–100% increase in leakage), although in absolute value, the additional leakage was modest and the buildings remained very airtight. In general, it is concluded that pressurization tests render robust results in extremely tight construction, but with respect to ambitious leakage limits, test conditions and small preparation details such as the locking of window hardware can easily determine whether the dwelling will pass or fail.

Results and problems in the construction phase of the SuperKEKB vacuum system

The SuperKEKB, the upgrade of the KEKB, is an electron–positron collider with asymmetric energies, that is, 7.0 GeV electrons and 4.0 GeV positrons, designed for a luminosity of 8 × 1035 cm−2 s−1. As a key item of the upgrade project, a new vacuum system for the SuperKEKB has been in construction since 2010. Over 1000 beam pipes, vacuum pumps, bellows chambers, and other various vacuum components had almost been fabricated in 2014. All the new beam pipes were baked as a general rule before being installed in the KEKB tunnel. A thin TiN film with a low secondary-electron yield was coated on the inside of the beam pipes for the positron ring as a countermeasure against the electron cloud effect. The performance of the new built-in nonevaporable getter (NEG) pumps and the step-less connection flanges met the expectation. Although several problems such as damage to the bellows chambers due to a large earthquake, cracking of the welding lines of the aluminum beam pipes, and a relatively high air-leak rate at the connection flanges occurred during the construction work, approximately 99% of the beam pipes were successfully installed by the end of October 2015. The activation of the NEG pumps in the tunnel started at the beginning of 2015 and has also been completed in approximately 97% of the ring. The installed beam pipes and the bellows chambers in the tunnel were aligned to their specified positions as the final step of the installation work. The vacuum system was ready in 2015 with the aim of starting the first commissioning in 2016. The various experiences during the construction phase reported here will be a useful reference for the design and construction of other accelerators in the future.

Prolonged air leakage in secondary spontaneous pneumothorax: is proportion of emphysema important?

Prolonged air leakage is the most common complication that can cause severe problems in cases of secondary spontaneous pneumothorax (SSP). The purpose of this study was to explore whether Goddard Classification Score (GCS) can be a marker of prolonged air leakage, particularly during the post-operative period, for patients with emphysema. Fifty patients, who underwent tube thoracostomy for SSP, were retrospectively evaluated. For the evaluation of emphysematous on the preoperative computed tomography image, visual scoring system described by Goddard was used. The correlations between age, duration of hospitalization, duration of drainage, number of pneumothorax episodes, prolonged air leakage and GCS parameters, were evaluated. When 50 patients were scored, based on GCS, the distribution was as follows: G1: four cases, G2: 16 cases, G3: 17 cases, and G4: 13 cases. The mean number of pneumothorax episodes was 1.3 ± 0.5, the mean duration of drainage was 15.7 ± 11.3 days, and the mean duration of hospitalization was 9.2 ± 5.1 days. Prolonged air leakage was seen in 26 (52.2%) cases. The rate of prolonged air leakage was significantly higher in higher GCS cases (P = 0.035). There was a positive correlation between age and GCS (P = 0.011). The number of pneumothorax episodes rose significantly with increasing GCS (P = 0.011). The duration of hospitalization increased with the growing number of pneumothorax episodes (P = 0.027). Prolonged air leakage and the recurrence rate of SSP rise with increasing GCS. Taking this condition into consideration in the treatment algorithm can be helpful for clinicians in patient follow-up.

Specifics of Building Envelope Air Leakage Problems and Airtightness Measurements

In addition to transmission heat loses the infiltration of outdoor air can cause significant heat losses. The external building envelope should be airtight in order to prevent uncontrolled cold air infiltration. The article analysis modern building materials and structures influence on airtightness. The practical measurements of renovated buildings' airtightness are presented and compared to non-renovated buildings. In addition paper presents data on airtightness measurements of whole multi apartment building and single apartment in analyzed building taking inco accout properties of building materials. The airtightness of single apartment was evaluated with support pressure in neighbor apartments. The results show that the airtightness measurements of multi apartment building can be evaluated by measuring single apartment on last floor with support pressure in neighbor apartments. The practical measurement of renovated buildings had shown the air leakage rate q50 of typical Latvian construction after renovation is between 2.5 and 2.9 m 3 /(m 2 ·h). Since the building envelope has to minimize the heat loses (transmission and infiltration) and ventilation system either mechanical or natural has to provide necessary air exchange, the building envelope airtightness shouldn't be dependent on type of ventilation systems.

Prolonged air leak following lung resection - does Tri-staplerTM technology improve the incidence?

Prolonged air leak following lung resection leads to delayed discharge and increases risk of infection. The incidence of prolonged air leak (defined as greater than 7 days) is approx. 9% in the U.K. (SCTS Cardiothoracic Surgery database 2011). The Covidien Tri-staplerTM technology (Covidien, Mansfield, MA) claims to improve air leak rates following lung resection through improved vascularity at the suture line. We started using these staplers in August 2012.

Air Leakage of Concrete Floor and Foundation Junctions

Air leakage of the building envelope is a significant contributor to radon concentration levels. The aim of our work was to determine the air leakage rate through the foundation wall and the floor joint. Different sealing methods were investigated to compare their effect on the air leakage of the joint. Additional tests were made to gather information about the construction quality and the reproducibility of measurement results. The air leakage rate decreased between 1.3 and 86 times depending on the sealing method. Essentially, the air leakage rate was found to depend heavily on the quality of the construction works.

Improving the airtightness in an existing UK dwelling: The challenges, the measures and their effectiveness

Air infiltration, occurring through gaps in the building envelope, can contribute up to one third of total heat losses associated with older UK dwellings [1]. Therefore, reducing the rate of air leakage (i.e. improving air ‘tightness’) can have a positive effect in terms of decreasing space heating requirements.This study presents an investigation of the effectiveness of airtightness measures applied in a retrofit context to a UK dwelling. A phased programme of refurbishment work was undertaken to a test dwelling at the University of Nottingham campus, UK. Evaluation techniques, including building energy modelling (SAP 2009), air pressurisation tests and thermal imaging, were performed. The study demonstrates that the use of conventional draught-proofing measures can achieve a reduction in air permeability of over 30% when compared with the house base case value of 15.57 m3/(h.m2) @ 50 Pa. This reduction was only achievable with close attention to installation detail. Further measures of service penetration and floor sealing enabled the air permeability to be reduced to as low as 4.74 m3/(h m2) @ 50 Pa.Modelling of the test dwelling predicted an initial space heating supply energy requirement of 32,373 kWh, which was reduced to 23,197 kWh by a combination of the air tightness measures, insulation, and system (boiler and ventilation) improvements. Air tightness measures alone contributed to approximately 9% of the predicted total reduction, half of which was due to relatively straight-forward draught-proofing. Other more advanced air tightness measures were considerably more expensive, though cheaper approaches to their application could help reduce payback times.

Beyond the 3rd Generation of Planar SOFC: Development of Metal Foam Supported Cells with Thin Film Electrolyte

Manufacturing of thin and gas tight electrolyte is still a challenging issue for metal supported solid oxide fuel cells (SOFCs). In this work, we present a porosity graded multi-layer structure supporting thin film electrolyte. The substrate is made of NiCrAl metal foam impregnated with La-substituted SrTiO3 (LST) ceramic. Furthermore, a 20 µm thick composite anode functional layer with LST and gadolinium doped ceria (GDC) was deposited onto the substrate. The surface of the anode functional layer is later engineered with a suspension of nano-particles with 40 nm average particle size of yttria-stabilized zirconia (YSZ). This results in a mesoporous layer with smooth surface able to support a thin film GDC layers. Finally, a gas-tight GDC electrolyte was deposited by EB-PVD method. The thickness of the thin-film YSZ layer and the gas-tight GDC layer was approximately 1 µm and 2 µm, respectively. Button half cells with size up to 25cm² were successfully produced showing an air leakage rate down to 7.0*10-4 (hPa*dm3)/(s*cm2), satisfying the gas-tightness quality control threshold of the state of the art metal supported SOFCs at DLR. Full cells with LSCF cathodes were then produced and electrochemically tested presenting stable Open Circuit Voltage near to 1V. Results will be presented and discussed in this paper by confronting the performance with the cell microstructure. Key Words: metal foam, thin-film, electrolyte The research leading to these results has received funding from the European Union‘s Seventh Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement n° 303429

Beyond the 3rd Generation of Planar SOFC: Development of Metal Foam Supported Cells with Thin Film Electrolyte

The manufacturing of thin and gas tight electrolyte in solid oxide fuel cells (SOFCs) remains challenging especially when alloys are used for the substrate. In this work, we present a porosity graded multi-layer structure supporting thin film electrolyte, as a further evolution of the metal supported planar cell architecture. The substrate is made of NiCrAl metal foam impregnated with La0.1Sr0.9TiO3-α (LST) ceramic. Furthermore, a 20 µm thick composite anode functional layer with LST and Gd0.1Ce0.9O2-α (GDC) was deposited onto the substrate. The surface of the anode functional layer is later engineered with a suspension of nano-particles with 40 nm average particle size of yttria-stabilized zirconia (YSZ). This results in a mesoporous layer with a smooth surface. Finally, a gas-tight GDC electrolyte was deposited by EB-PVD method. The thickness of the thin-film YSZ layer and the gas-tight CGO layer was approximately 1 µm and 2 µm, respectively. Button half cells with size up to 25cm² were successfully produced showing an air leakage rate down to 0.7 Pa·m·s-1 satisfying the gas-tightness quality control threshold of the state of the art metal supported SOFCs at DLR. Full cells with La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathodes showed an OCV of 0.97 V at 750°C and power density of about 80mW/cm² was obtained at 0.7 V.

Assessing uncertainty in housing stock infiltration rates and associated heat loss: English and UK case studies

Strategies to reduce domestic heating loads by minimizing the infiltration of cold air through adventitious openings located in the thermal envelopes of houses are highlighted by the building codes of many countries. Consequent reductions of energy demand and CO2e emission are often unquantified by empirical evidence. Instead, a mean heating season infiltration rate is commonly inferred from an air leakage rate using a simple ratio scaled to account for the physical and environmental properties of a dwelling. The scaling does not take account of the permeability of party walls in conjoined dwellings and so cannot differentiate between the infiltration of unconditioned ambient air that requires heating, and conditioned air from adjacent dwellings that does not.A stochastic method is presented that applies a theoretical model of adventitious infiltration to predict distributions of mean infiltration rates and the associated total heat loss in any stock of dwellings during heating hours. The method is applied to the English and UK housing stocks and provides probability distribution functions of stock infiltration rates and total heat loss during the heating season for two extremes of party wall permeability. The distributions predict that up to 79% of the current English stock could require additional purpose-provided ventilation to limit negative health consequences. National models predict that fewer dwellings are under-ventilated. The distributions are also used to predict that infiltration is responsible for 3–5% of total UK energy demand, 11–15% of UK housing stock energy demand, and 10–14% of UK housing stock carbon emissions.

The effect of an enclosure retrofit on air leakage rates for a multi-unit residential case-study building

This paper presents a relatively new, simple and robust, method for air leakage testing. A thirteen-story multi-unit residential building was tested for air leakage before and after an enclosure retrofit. The building suites had a pre-retrofit NLA50 average of 6.77cm2/m2 and an average post-retrofit NLA50 of 2.82cm2/m2—a 58% betterment. The effect of the retrofit on air leakage rates was assessed and compared to other multi-unit residential buildings across Canada and USA. The case study building was significantly tighter than other multi-unit residential buildings included in published studies. Recommendations were made for field-testing procedures in order to maximize the potential for accurate measured flow characteristics. Field-testing for air-tightness needs to be standardized in order for useful comparative results to be generated in order to inform future research and operational considerations for the multi-unit residential building stock across North America.

Simulation of construction ventilation in deep diversion tunnels using Euler–Lagrange method

Removal of harmful components is a major concern in the construction ventilation of deep diversion tunnels with heat exchange. The intersecting tunnels and air leakage along the long duct system increase the difficulty of smoke extraction. A 3D unsteady Euler–Lagrange two-phase turbulence model is utilized with the aim of understanding the pollutant discharge problem caused by the storage heat effects, the intersecting tunnels and air leakage along the long duct system. The effects of air leakage, the gas–solid heat exchange, the gas–solid interaction forces and the particle collision are considered. A grid-sensitivity study was performed to obtain a reasonable mesh resolution. The model is validated based on the in-situ ventilation test data. The construction ventilation for the diversion tunnels of the Jinping Second-cascade Hydropower Station in China is taken as a case. The air field distribution, the distribution of heat transfer coefficient, the air leakage rate per 100m, the particle collision force and dust particles migration tracks are analyzed. The dust particles collisions have a negative influence on ventilation and dust exhaust. Most dust particles move toward the tunnel outlet along the tunnel bottom with the effects of airflow and density flow, whereas part of the dust particles move upwards under the effect of buoyancy.

Hermeticity and Reliability of Au-Au Thermocompression Bonds, Realized at Low Temperature

Au-Au thermocompression bonding is a reliable and space-efficient method for wafer-level sealing [1]. It is commonly performed at bond temperatures of 300 – 400 oC [1-3] and bond pressures of 0.5 – 15 MPa [1, 3]. He leak rates of 2.7 ×10-10 atm cm3 s-1 have been presented [2]. We have explored the lower temperature limits for realizing Au-Au thermocompression bonds with high yield. Further, we have investigated the reliability of the bonds when subjected to environmental stress test conditions. Test laminates were prepared by bonding bottom Si wafers to top Si wafers with 481 membranes with a nominal thickness of 36 µm and nominal dimension 2.5 × 2.5 mm2. A cross-sectional view of a single die is shown in Figure 1. Both wafers had a SiO2 layer of 7500 Å. Metal layers of 400 nm TiW and 1.2 µm Au were sputter deposited and patterned to form frames on all wafers. The nominal width of the bonding frames was 20, 40, 80, and 200 µm. The total bonding area on a 150mm wafer was 504 mm2. Top and bottom wafers were aligned and bonded in vacuum ambient in a SB6e (Suss MicroTec.) bonder applying a tool pressure of 2266 mbar for 15 minutes at temperatures ranging from 150 oC to 300 oC. The targeted bond pressure was 8.5 MPa. The bonded laminates and parameters are given in Table 1.After bonding, the inward deflection of the membranes was measured by white light interferometry. The wafers were subjected to environmental stress conditions consisting of steady-state life test (exposure to 150 °C for 1000 h), 50 cycles of thermal shock from -65 °C to +200 °C, and 10 cycles in 90 – 100 % humidity from 25 °C to 65 °C. Characterization was done by investigating the membrane deflection after each test.The hermeticity yield was defined as the percentage of membranes deflecting inwards by more than 2 µm after bonding, and is shown in Figure 1 and Table 1. An average membrane deflection was 5.5 µm. Laminates Au200 and Au250 had hermeticity yields of 65 – 75 % for all frame widths, except 200 µm wide frames on Au200. Laminate Au150 had yields of 3 – 11 % for all frame widths. Laminate Au300 appeared to be misaligned since the yield was below 2 % for frames of widths 20 – 80 µm and 54 % for 200 µm wide frames. The results indicate that at 8.5 MPa bond pressure, there seems to exist a threshold temperature for bonding between 150 oC and 200 oC. Bonding at 200 oC and 250 oC seem to be of equal quality.The membrane deflection measurements provided an estimate of the maximum air leak rate of 7.4×10-12 atm cm3 s-1. Longer storage times can reveal more accurate leak rates. No changes in membrane deflection were observed in any of the laminates after exposure to the steady-state life test, thermal shock test or moisture resistance test. The results indicate that Au-Au thermocompression bonds realized at 200 oC and 250 oC are hermetic and can withstand environmental stress test conditions.