Fume Hood Research Articles

The Area Measurements in the Tritium Laboratory Within NIPNE Magurele

This paper reports the results of radiological measurements taken for the last 3 years in the controlled area and adjacent zone of the Tritium Laboratory of the the Horia Hulubei National Institute for Physics and Nuclear Engineering, Magurele. The radiological characterization has been performed by determination of total and removed tritium contamination for the following surfaces: pavement, walls, windows, radiochemical tables, radionuclide fume cupboards, glove boxes, and sinks. The fixed tritium contamination does not present representative radiological risk because beta particles emitted by tritium are unable to penetrate the skin. The removed tritium contamination represents that component of the total surface contamination that can be taken by mechanical processes. The removed contamination was analyzed as a priority because it represents the main radiological risk factor in tritium laboratories. The determination of surface contamination has been carried out by scanning of the analyzed surfaces using an LB 1230 UMo tritium surface monitor with an LB 1230 detector and by a smear test using extruded polystyrene smears followed by measurement of the removed activity with a liquid scintillation counter. The total surface contamination values, obtained by scanning, were below the detection limit of the equipment, except for radiochemical hood surfaces. The removed tritium contamination determined values are in the domain of 5 … 450 Bq/dm2. At the department level, the obtained values for surface tritium contamination are at the background level.

Changing Behavior Through Design: A Lab Fume Hood Closure Experiment

One fume hood in a laboratory can use as much energy as three homes per year. When a fume hood is in use, its door (or "sash") needs to be open, but otherwise it should be closed for safety, as well as to conserve energy. This paper examines strategies to promote fume hood closure behavior. A behavior change experiment conducted in the field tested whether a design signifier (sticker) and comparative feedback extracted from automated building and equipment data would decrease the number of times people left fume hoods open when not in use (while spaces were unoccupied or the hoods were inactive). The experiment included a control building where no fume hood intervention was implemented. The sticker and feedback together resulted in significantly fewer instances of hoods being left open (a 52.8% reduction overall). One year later, with the sticker in place and without further feedback, the instances of hoods being left open when the space was occupied but the hoods were inactive remained significantly lower than baseline. In addition to providing a low-cost strategy to bring about behavior change, findings from this study suggest opportunities to improve fume hood design and to use automated building data to provide laboratory workers with feedback to change their behavior.

The Levels of Antinutritional Factors in Moringa Oleifera and Vernomia Amygdalina Leaves Found in Some Part of Plateau State, Nigeria

In this research work, various materials were used and they include; apparatus such as fume cupboard, measuring cylinder, spatula, centrifuge, pipette and reagent such as Na2CO3, CaCl2, H2SO4, HCl, AgNO3. The nutrient composition of V. Amydalina are: Phytate 11.9 ± 0.01 (mg/100g), oxalate 244.02 ± 0.57 (mg/100g), tannins 1.28 ± 0.50 (mg/100g), alkaloid 1.66 ± 0.01%, HCN 2036.00 ± 0.58 (mg/100g) and M. oleifera are: phytate 10.58 ± 0.01 (mg/100g), oxalate 334.33 ± 0.67 (mg/100g), tannin 8.19 ± 0.01 (mg/100g), alkaloid 1.72 ± 0.01% and HCN 3998.30 ± 0.49 (mg/100g). These results showed that V. Amydalina leaves could be a bioresources for Zn as a result of the low level of phytate. But they are not Cu bioavailable resources due to the high level of oxalate. Hence, people are encouraged to utilize V. amydalina and M. oleifera leaves as a good source of micronutrient particularly those prove to be bioavailable.

A study of separated flows at inlets of flanged slotted hoods

Slotted hoods are used for capturing contaminants released by extended sources. As a means of improving of its efficiency, the capture velocity can be increased by using flange and the aerodynamic drag can be reduced by shaping the hood after discovered vortex zone boundaries. The goal of study is to identify regularities in the behavior of outlines of the two vortex zones formed at the inlet of a flanged slotted hood and the velocity distribution near the exhaust hood given different flange lengths and tilt angles. Study relied on a natural experiment and numeric simulations in the ANSYS® Fluent software and using our improved version of the discrete vortex method. Vortex zones have never been studied in such detail so far. For the first time ever, the outline of the second vortex zone has been successfully identified. Coefficients of similarity for the first vortex zone outlines have been determined. New airflow velocity distribution patterns have been identified. We have demonstrated that failure to account for flow separation led to wrong conclusions in the past concerning maximum axial velocities with a flange opening angle of 90° within the entire range of distances away from the exhaust hood. At distances 0.7 times gauge and less, axial velocity reaches its maximum near the flangeless slotted hood. Furthermore, we were able to determine velocity distributions further away from the exhaust hood centerline where relations involving tilt angle get even more complex. We believe our findings are relevant for the design of efficient, energy-saving exhaust hoods.

Indoor thermal environment and air quality in Chinese-style residential kitchens.

This paper reviews the published literature on indoor thermal environment and air quality in Chinese-style residential kitchens (CRKs). The paper first discusses typical characteristics of CRKs, including kitchen layout, cooking methods, and ventilation systems used. Next, the paper describes the current state of the indoor thermal environment and air quality in CRKs. Finally, this paper summarizes measures to control and improve the environment inside CRKs. The results indicate that the indoor environment of CRKs is too hot in summer and exhibits a large vertical temperature difference. No appropriate model was available for accurately evaluating the thermal environment in CRKs. At the same time, CRKs are highly polluted by COx, NOx, TVOC, and particulate matter (PM). Although existing exhaust hoods could improve the indoor environment to some extent, the use of a combined exhaust, make-up air, and air-conditioning system should be considered to provide a comfortable and healthy environment in CRKs.

Influence of the scheme of air exchange organization in the room on the efficiency of the air-jet hood of the heat treatment chamber

Local exhaust ventilation allows maximizing the localization of hazards with minimum values of air exchange in the room. For the study, the design of a local exhaust in the form of an air-jet hood at an open doorway of the UKM Classic M 2005 chamber by Mauting was adopted. Geometric models have been developed, including a heat treatment chamber, a room from which the chamber is loaded, a supply and exhaust hood over the door from the chamber to the room, and a supply air duct with air distributing devices. The results of a computational experiment on modeling the operation of the local exhaust ventilation system of the heat treatment chamber are presented. The STAR-CCM+ software package was used as a calculation program. The calculation results were analyzed. The influence of the air exchange scheme (location of the supply devices) in the room on the efficiency of the local exhaust devices (supply and exhaust hood) has been established.

Phytoremediation of lead in Mineral, distilled and surface water using Pennisetum purpureum and Allium fistulosum

An eco-friendly bioremediation technology that removes heavy metals and contaminants in soil and water using plants is known as phytoremediation. It has been an effective and affordable remediation method to absorb contaminants. Hence, this paper aims to analyze the ability of two plants to absorb lead (Pb) in three types of water, i.e., distilled, mineral and surface water. Two green plants used in this research were, Napier grass (Pennisetum purpureum) and red scallion (Allium fistulosum). The plant was grown for 14 days in water-only medium while a portion Pb (NO3)2 solution was added as a lead contaminant. The research was carried out in a fume cupboard equipped with a tungsten bulb as a light source. The light intensity, humidity, temperature, and concentration of Pb (NO3)2 were monitored. The lead concentration was measured by analyzing the lead content in liquid sample taken from the beaker where the plants were grown. The concentration of lead in the water were analyzed by using atomic absorption spectroscopy (AAS) at 283.3 nm wavelength. In 14 days of experiment, the highest rate of lead absorbed was achieved by using Pennisetum purpureum plant in distilled water, which is 2.188 ppm/day. However, the Pennisetum purpureum showed the highest amount of lead removed (86.99%) in surface water. While for Allium fistulosum plant, the highest rate of lead absorbed was found by using distilled water which is 0.749 ppm/day. The Allium fistulosum showed the highest amount of the lead removed (49.22%) in distilled water. Additionally, plants named mung bean (Vigna radiata) and (Allium schoenoprasum) were also studied and were unable to absorb the lead contaminant under the same experimental procedures.

Exposures during wet production and use processes of nanomaterials: a summary of 11 worksite evaluations.

From 2011–2015, the National Institute for Occupational Safety and Health Nanotechnology Field Studies Team conducted 11 evaluations at worksites that either produced engineered nanomaterials (ENMs) via a wet process or used ENMs in a wetted, suspended, or slurry form. Wet handling or processing of ENMs reduces potential exposure compared to dry handling or processing; however, air sampling data indicated exposures may still occur. Information was gathered about each company, production processes, ENMs of interest, and control measures. Exposure assessments included air sampling using filter media, surface wipe sampling, and real-time particle counting by direct-reading instruments. Electron microscopy analysis of air filters confirmed the presence of ENMs of interest (10 of 11 sites). When a method was available, chemical analysis of filters was also used to detect the presence of ENMs (nine of 11 sites). Wipe samples were collected at four of the 11 sites, and, in each case, confirmed the presence of ENMs on surfaces. Direct-reading data showed potential nanomaterial emissions (nine of 11 sites). Engineering controls included fume hoods, cleanrooms, and enclosed processes. Personal protective equipment was required during all 11 evaluations. Recommendations to address potential exposures were provided to each company following the hierarchy of controls.

高効率捕集性能を有する局所排気装置の設計手法に関する研究 (第2報)吸い込み口形状が横風条件下における排気性能に及ぼす影響

高効率捕集性能を有する局所排気装置の設計手法に関する研究 (第2報)吸い込み口形状が横風条件下における排気性能に及ぼす影響

Blowing Steam into the Boundary Layer on the Outer Wall of the Axial Exhaust Hood

The paper is devoted to experimental verification of flow on the steam turbine axial exhaust hood model. The main goal of the submitted paper is to evaluate the influence of additional air blowing into the boundary layer in the axial exhaust hood on the change of the pressure recovery coefficient. The experimental model was supplemented with a blowing track and fitted with a centric orifice for mass flow measurement. Several variants were measured with various types of inner struts and supports inside the hood for two values of Mach number at the diffuser inlet.

Survey study on Chinese commercial kitchen exhaust fume systems in Tianjin

Exhaust fume system plays an important role in ensuring indoor and outdoor environment in the Chinese commercial kitchens (CCKs). To investigate the current status of exhaust fume systems in CCKs (CCKEF), on-site survey of cooking appliances, components of CCKEF including exhaust hoods, purification equipment, exhaust fans, discharge form and replacement air, outdoor grease accumulation, and indoor environment, was conducted in 41 CCKs in Tianjin. Results showed that: (1) the diversity and number of cooking appliances was related to kitchen area. 76.19% of stir-frying stoves were located at the end of the appliance lines. (2) Most of the CCKEFs were composed of wall-mounted canopy hood (94.12%), terminal static purifier (98.04%), centrifugal fan (100%), roof-located discharge (66.67%) and transfer air (100%). 47.06% of canopy hoods were equipped with baffle filters, including 29.41% tube-type, 9.80% plate-type and 7.85% strainer-type. The nameplate purification efficiency of purifiers met the fume emission standard. 81.08% of purifier manufacturers were from Beijing. (3) Outdoor grease accumulation was serious. 72.73% had much or a lot of grease accumulation. Cleaning period and the number of burners were the major influence factors. For systems with over 4 burners, the cleaning period was better within 2 months. (4) 70.8% of chefs were dissatisfied with the thermal comfort in CCKs. Thermal and wet sensation varied with seasons and summer was the most unsatisfactory season. Over 80.0% of chefs felt fumes overflowing and interfering noise. The indoor environment in CCKs needed improvement. Survey results can provide reference for the designing of CCKEF in China.

Study on limit flow ratio method for a lateral exhaust hood above high-temperature buoyant jets

A local lateral exhaust hood can be used to capture the contaminated airflow in the industrial production process. For the design of the lateral exhaust hood, the flow ratio method is commonly adopted. However, there are three major concerns in the existing calculation formula of the limit flow ratio for the lateral exhaust hood: 1 The influence of the horizontal width of the hood is not considered. 2 The influence of the installation height of the hood is not accurately presented. 3 The influence of temperature difference between polluted air flow and environment is not considered. By analyzing the variation of the limit flow ratio of the hood with the above three different influencing factors, the existing calculation formula of the limit flow ratio for the lateral exhaust hood is corrected, and the limit flow ratio correction formula is obtained when the temperature difference Δt = 0∼1200 °C. Therefore, the improved formula of the limit flow ratio for a lateral exhaust hood could guide a more precise design of the exhaust system, which is significant to save energy, ensure the workers’ health, and step into sustainable development.

Lateral ventilation performance for removal of pulsating buoyant jet under the influence of high-temperature plume

Lateral exhaust systems have commonly been applied to capture polluted buoyant jets in many industrial processes, such as casting and metallurgy. Compared with the normal conditions of design manuals, the capture efficiency of a lateral exhaust hood (LEH) is often weakened by two factors in actual processes: the unsteady buoyant jet released from the operating surface, and the plume formed above a high-temperature workpiece placed between the LEH and the operating surface. In this study, through experiments and numerical simulations, a pulsatile phenomenon was found in the velocity and concentration distribution of the unsteady buoyant jet. Results show that the contaminate escape ratio is pulsatile; it rises with the instantaneous increase in the buoyant jet velocity and gradually decreases to a constant value. This study not only reveals the air distribution of pulsating buoyant jet but also analyses the effect of the pulsating buoyant jet and high-temperature plume on lateral ventilation system capture efficiency and provides a possible guidance for future design of new building ventilation technologies.

Impact of Source Position and Obstructions on Fume Hood Releases.

A fume hood is the most central piece of safety equipment available to researchers in a laboratory environment. While it is understood that the face velocity and sash height can drastically influence airflow patterns, few specific recommendations can be given to the researcher to guide them to maximize the safety of their particular hood. This stems from the issue that fundamentally little is known regarding how obstructions within the hood can push potentially harmful particles or chemicals out of the fume hood and into the breathing zone. In this work, we demonstrate how the position of a typical nanoparticle synthesis setup, including a Schlenk line and stir plate on an adjustable stand, influences airflow in a constant velocity fume hood. Using a combination of smoke evolution experiments and the aid of computational fluid dynamics simulations, we show how the location and height of the reaction components impact airflow. This work offers a highly visual display intended especially for new or inexperienced fume hood users. Based upon our studies and simulations, we provide detailed guidance to researchers and lab technicians on how to optimally modify reaction placement in order to protect the breathing zone while working.

Airborne particles from cooking oils: Emission test and analysis on chemical and health implications

Inhalation of cooking oil fumes can be detrimental to human health. This study aims to evaluate the emission characteristics of different cooking oils and attempts to identify a cooking oil that emits the least fine particulate matter (PM) during heating. The yield of particles of six different size increments were examined for six commonly used cooking oils: vegetable, canola, corn, olive, peanut, and coconut oils. Both the chemical and structural properties of the oils were analyzed to explain for variance in the quantity of particle emissions and distribution of particulate sizes among oils. The study further compared the oil particle accumulation in a typical cooking facility with and without a smoke exhaust hood. Of the oils examined, coconut and olive oil produced the most particles at low temperatures; peanut and canola oil produced the most particles at high temperatures. Fume inhalation can be greatly decreased through ventilation at both the half power and full power tested. The inhalation of particulate matter expelled from the heating of cooking oils does not exceed government regulation levels for typical household cooking, but inhalation for extended lengths of time might exceed U.S. and Australian regulation guidelines.

Study on the control effect of two different forms of side suction hoods on pollutants

A suitable exhaust hood form has a great influence on the control effect of pollutants. This paper uses CFD technology to numerically simulate the airflow distribution characteristics and pollutant concentration distribution characteristics of the side hood before and after improvement. The results show that: (1) The airflow of the improved side suction hood is introduced from the front of hood to make the fresh air pass through the breathing area first and then takes away the hazardous substances, which is beneficial to the breathing health of workers. (2) When the exhaust velocity (V) is more than 3.5m/s, with the increase of the exhaust velocity, the concentration hazardous substances at each control point of the two forms of exhaust hood tends to be stable gradually. (3) When the exhaust velocity is less than 3.5m/s, the control effect of side suction hood with baffle is better than that without baffle, and the percentage of hazardous substances concentration at the same control point can be reduced by 12%-29%, or even higher.

Single-Cylinder Steam Turbine for Powers Up to 100 MW with Axial Exhaust Pipe

The design of a new single-cylinder steam turbine for powers up to 100 MWwith an axial exhaust pipe is discussed. The turbine belongs to turbine class A.3. It can operate in steam power and steam-gas cycles. It is intended for operation at newly commissioned power plants, including those with air condenser systems (ACS). A.3 class turbines are single-shaft single-cylinder machines with loop-type steam circulation in the flow path, and can be used both for radial and axial exhaust hood arrangements. In this paper, an axial exhaust version with an air condenser system is described. The turbine cylinder consists of four major parts: steam intake path made from two cast housings– inner and outer– along with intermediate and exhaust welded parts. The flow-through part is organized as follows: on passing through the left flow stages, steam is diverted by 180° and is directed along the inter-housing space to the right flow stages. The full design cycle for this single-cylinder turbine with an axial exhaust pipe was completed in less than 9 months. The design documentation for this steam turbine consists entirely of 3D-models (100% of component parts and assemblies).

Respiratory deposition of ultrafine welding fume particles

The inhalation and the deposition of welding-generated ultrafine particles in welders’ respiratory tracts have been linked to severe pulmonary impairments. In the present study, a mobile aerosol lung deposition apparatus (MALDA) was developed and applied to study the respiratory deposition of ultrafine welding fume particles. The MALDA was constructed with a set of physiologically representative human tracheobronchial airway replicas made with high-resolution 3D printers. Ultrafine welding fume particles were generated in a welding fume chamber and delivered to the MALDA. A series of respiratory deposition experiments were carried out using the MALDA to investigate the deposition of ultrafine welding fume particles in different airway generations of the tracheobronchial airways. The results showed that the fractional deposition of ultrafine welding fume particle in the human tracheobronchial airways down to the 9th airway generation could be readily and systematically measured by the MALDA. The estimated cumulative respiratory deposition ranged from approximately 9–31% for ultrafine welding fume particles between 10 and 100 nm in diameter. The results acquired demonstrated that the MALDA developed has the potential to become a useful apparatus in the future to estimate the respiratory deposition of ultrafine particles in real workplaces.

In Your Face: Consideration of higher risks for chemical exposure to persons with disabilities in laboratories

Workforce diversity is seen to have a competitive advantage over organizations that are not diverse. It is observed that these organizations have advantages in creativity, problem-solving, decision-making, and overall quality of results, among other observed outcomes. The Americans with Disabilities Act of 1990, passed nearly 30 years ago, opens doors for people with disabilities to enter the workforce. While many under-represented groups are increasing participation, such as women, participation of people with disabilities remains static. This article focuses only on mobility and motor impairments or physical difficulties that could put individuals with disabilities at greater risk of exposures from hazardous chemicals while working in laboratories. Dosage experienced is potentially greater in people who are below the historical standard chemical fume hood testing height of 178 cm (70 inches). Ergonomic concepts and anthropometric adult-measurement data can help OH&S, IH, EH&S professionals to investigate and mitigate physical conditions in laboratories that could increase exposure risks of hazardous fumes, vapors, and airborne particulate to persons who use wheelchairs or who must be seated while operating chemical fume hoods and working at open benches. More exposure tests need to be conducted to assess risks for able and disabled laboratory science workers and students in STEM disciplines. Chemical fume hood testing protocols and certification may need further amendments to acknowledge the data generated and validated in exposure research that includes critical ergonomic factors.

Investigation of influential factors on laboratory fume hood containment performance

The necessity of understanding the potential limitations of fume hood applications is widely neglected because the user tends to consider that the fume hood itself has been certified prior to installation. However, a wide variety of conditions in real laboratory environments may create serious negative impacts on the performance of fume hood containment, consequently increasing the personnel exposure to hazardous materials. The work reported in this article aimed to understand these negative impacts through a comprehensive numerical simulation together with a field experiment. The simulation provided the information of the airflow pattern and contaminant distribution inside the fume hood. The accuracy of the model was verified by an on-site experiment with an electron capture detector and off-site gas chromatography analysis. It is noteworthy that the tracer gas emission character yields a much stronger correlation with the containment failure of a fume hood, compared with the thermal challenge. Better understanding of the effect of those influential factors can contribute to some reference value in engineering control of hazardous material exposure in the laboratory environment. The methodology taken in this study can be referred to by occupational health officers and ventilation engineers to investigate other causes of low hood containment performance.