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Surface treatment baths - Ventilation and other means of improving the environment
Ytbehandlingsbad - Om ventilation och andra åtgärder för en bättre miljö [en sueco]
Contents: responsibilities of management, supervisory staff, safety officer and electroplaters for improving the workplace environment; enclosure of tanks with exhaust; respiratory and skin hazards; practical measures against atmospheric pollutants (replacement of cyanides by less toxic products, reduction in concentration of chemicals, use of low current density, addition of surface-active agent, lowering of roof height); appropriate ventilation systems (enclosure with air locks or negative pressure, air curtains); control of efficacy and maintenance of exhaust equipment; economic aspects; practical solutions.
Arbetarskyddsfonden, Sveavägen 166, 113 46 Stockholm, Sweden, no date. 23p. Illus. 10 ref.
Tratamiento eficaz del aire en fundiciones
The most highly polluting foundry operations are: melting, pouring, precooling of the mould, removal from the mould and knockout, cooling of castings, fettling, sand preparation. Details are given of ventilation systems using local exhaust at the source, and of air filter systems, dust collectors (wet, Bahco multicyclones) and heat exchangers that can be used in foundries.
Prevención, Jan-Mar. 1980, No.71, p.32-40. Illus.
Validation of a recommended approach to recirculation of industrial exhaust air. Volume II
The validity of the approach recommended in DHEW(NIOSH) Publication No. 78-124 (CIS 79-85) was evaluated by studying its application in 4 plants with newly installed exhaust air recirculation systems. The plants were a lead battery assembly operation, a woodworking operation, a wet grinding process, and an enamel blending process. Conclusions concerning the recommended approach and recommendations for improvement and research are presented. The recommended approach provided a useful method for examining the feasibility of recirculating exhaust air.
National Institute for Occupational Safety and Health, 4676 Columbia Parkway, Cincinnati, Ohio 45226, USA, Aug. 1979. 195p. Illus. 18 ref.
Validation of a recommended approach to recirculation of industrial exhaust air. Volume I
The validity of the approach recomended in DHEW(NIOSH) Publication No.78-124 (CIS 79-85) was evaluated by studying its application in the design of new recirculation systems and in retroactive applications to existing systems. Recirculation of air contaminated with particles, mists, vapours and fumes using fabric filters, baghouses, scrubbers, electrostatic precipitators and carbon absorbers as air cleaning systems was studied in the context of spring grinding, hard chrome plating, dry cleaning, and welding and degreasing operations. The approach provides and appropriate framework for the design of recirculation systems and is of value in identifying and resolving problems of health and safety.
National Institute for Occupational Safety and Health, 4676 Columbia Parkway, Cincinnati, Ohio 45226, USA, Aug. 1979. 202p. Illus. 18 ref.
Evaluation of design criteria for recirculation of industrial exhaust air
The validity of a recommended approach to the recirculation of exhaust air (CIS 79-85) was evaluated by studying its application in the design of new recirculation systems and in retroactive applications to existing systems. This evaluation, which includes 6 detailed case studies of the application of recommendations to recirculation systems for spring grinding operations, hard-chrome plating plants, dry cleaning plants, welding operations and degreasing operations, indicates that the approach provides an appropriate framework for the design of recirculation systems and is of value in identifying and resolving health and safety problems.
National Institute for Occupational Safety and Health, Division of Physical Sciences and Engineering, Cincinnati, Ohio 45226, USA, Apr. 1979. 202p. Illus. 21 ref.
Computer program for recirculation system design
A computer programme which can be used to evaluate the effects of the recirculation of exhaust air on the workplace and to optimise system design configuration to provide the greatest energy savings while maintaining a safe and healthful workplace, is presented. The programme is based on models developed from a set of analytical procedures for determining the effects of the recirculation of exhaust air. The pre-circulation and post-circulation conditions, limitations and the methodology of use of the models are described. The programme language is Fortran IV. Example problems are used to demonstrate programme use.
National Institute for Occupational Safety and Health, Division of Physical Sciences and Engineering, Cincinnati, Ohio 45226, USA, Apr. 1979. 39p.
Fundamentals governing the design and operation of local exhaust systems.
This standard comprises the fundamentals of good practice in industrial local exhaust systems installed to prevent unhealthy or unsafe environmental conditions or to minimise nuisances. Definitions are followed by sections devoted to: plant construction and layout; exhaust hoods; exhaust ducts; air-cleaning equipment; exhausters (fans, turbo-compressors, positive displacement blowers, ejectors, fan selection); construction and installation; operation and maintenance; checking of operation (air-flow measuring devices). Tables: velocity pressures for different air velocities, density correction factors, altitude, temperature and air density.
American National Standards Institute, 1430 Broadway, New York, N.Y. 10018, USA, 29 Mar. 1979. 72p. Illus. 11 ref. Price: US$11.50.
Speight F.Y., Campbell H.C.
Fumes and gases in the welding environment.
This report summarises 5 studies and several literature surveys conducted to evaluate the extent to which ventilation may control the exposure of the welder to harmful fumes and gases and to investigate the nature of the various fumes and gases generated in arc welding, in brazing with silver-based filler metals, in thermal spraying and in oxyfuel gas cutting. Tables show what fumes and gases are generated by 14 types of covered electrodes for shielded metal arc welding, 7 electrodes for flux cored arc welding, 11 gas metal arc solid electrodes, 2 BAg-class brazing filler metals, and 3 thicknesses of carbon steel plate severed by oxyacetylene and oxymethane cutting under various conditions. The data can be used to determine the blower capacity and exhaust flow rates needed for ventilation.
American Welding Society, 2501 N.W. 7th Street, Miami, Fl. 33125, USA, 1979. 232p. Illus. 80 ref.
Allander C., Ljungqvist B.
Air movements - the dispersion of pollution. Exploratory tests using IR techniques.
A method comparable to smoke photography which shows up gas accumulations rather than smoke particles is described. Use was made of the fact that most gases and vapours of interest to occupational hygiene have dipole moments in their molecular structure, so that they have absorption lines within the infrared region. The test apparatus is described and early test results are given. Sensitivity appeared to be of the order of 100ppm/cm, using primitive experimental conditions. The dynamic process of dispersal of gas was also filmed: different colours corresponded to different extinction values. The wake of a person working at a fume cupboard can give rise to extensive release of gas from the cupboard even when work is performed with the door half closed.
Document D16:1979, Svensk Byggtjänst, Box 7853, 103 99 Stockholm, Sweden, 1979. 8p. Illus. 2 ref. Price: Swe-cr. 20.00.
Some observations on the interaction between air movements and the dispersion of pollution.
Research in the field of aerodynamics to find an answer to 2 questions: 1. Is it possible, in rooms with normal ventilating air flow, for areas to exist which are so free of turbulent diffusion that gases and particles move with independent velocities? 2. If emission of pollution takes place within closed streamlines in a macroscopic vortex, will the concentration of impurities inside the streamline through the source become significantly higher than outside the streamline? A number of studies on models showed that the presence of a worker and his postures and movements have a considerable influence on the behaviour of pollutant clouds emitted at the workplace. The results of this research have a considerable bearing on the study of ventilation and local exhaust systems.
D8:1979, Svensk Byggtjänst, Box 7853, 103 99 Stockholm, Sweden, 1979. 112p. Illus. Price: Swe-cr.40.00.
USSR State Standards Committee (Gosudarstvennyj komitet SSSR po standartam)
Ventilation systems - Aerodynamic test methods.
Sistemy ventiljacionnye - Metody aėrodinamičeskih ispytanij [en ruso]
This standard (effective 1 Jan.1981) concerns airflow and pressure drop measurements in ventilation systems in buildings and industrial installations. Contents: selection of measurement points; measuring apparatus; preparation of tests; evaluation of results; safety conditions to be observed. Annex: calculation of error in airflow measurement when using a pressure sensor combined with a differential pressure gauge.
GOST 12.3.018-79, Izdatel'stvo standartov, Novopresnenskij per.3, 123557 Moskva, USSR, 5 Sep. 1979. 11 p. Illus. Price: Rbl.0.05.
Mine ventilation and refrigeration planning.
Description of a mine model for research in determining optimum cooling power of air circulated in underground mines using forced ventilation and refrigeration techniques. Mathematical formulae for airway heat load, air cooling capacity. Economic aspects, and effects of workplace conditions on productivity; acclimatisation; heat stroke hazard; description of a method for financial evaluation; results of analysis and review of optimisation methods; formulae giving optimal values for each parameter.
Journal of the Mine Ventilation Society of South Africa, Dec. 1979, Vol.32, No.12, p.225-235. Illus. 6 ref.
Local exhaust dust collector for special-purpose pneumatic grinders
Pyleotsasyvajuščee ustrojstvo pnevmošlifmašinki special'nogo naznačenija [en ruso]
Description of, and technical data concerning, a device which can be mounted on a portable grinder. It is composed of a cylinderical body, an axial-flow fan, a filter and fairing with a tapered duct leading to a dust collector. Machining dust is removed by exhaust ventilation and retained by the filter; the cleaned air is returned to the workplace environment by the fan. Dust collection efficiency is 99%.
Mestnyj proizvodstvennyj opyt v promyšlennosti, Nov. 1979, No.11, p.23.
Allander C., Ljungqvist B.
Air movement and pollutant spread - Photographic method
Luftrörelser - föroreningsspridning. Fotografisk metod [en sueco]
Description of a method for studying the aerodynamic behaviour of smoke or dust released in workplaces, and to evaluate the efficacy of ventilation and exhaust systems. Methodology: production of experimental smoke, photographic lighting and camera techniques. Example of a study carried out in a chemical laboratory equipped with exhaust ventilation.
Institutionen för värmeteknik, Kungliga Tekniska Högskolan, 100 44 Stockholm 70, Sweden, 1979. 31p. Illus. 4 ref. Price: Swe-cr. 25.00.
I fumi di saldatura [en italiano]
Considerations on the effects of welding fume on man; review of practical measures for exhaust ventilation and air purification: a portable device which exhausts welding fumes and also purifies the polluted air in welding booths by means of modular filter elements which can be chosen to deal with different types of welding fume; a series of exhaust nozzles are also available, connected to the device by a hose; each nozzle is designed for a different type of welding process.
Rivista di meccanica, Oct.(I) 1979, Vol.30, No.698/c, p.73-75. Illus.
Tracer gases in ventilation measurements
Merkkiaineet ilmanvaihtomittauksissa [en finlandés]
Measurements were carried out in 6 rotogravure printing works; the tracer gases used were CO2, N2O and SF6. SF6 was best for marking large air masses; only a very small amount of this tracer was needed, and could be detected <4x10-5cm3/m3. CO2 measurements are best for small rooms and halls with a low ventilation rate. Cost aspects of measurement and analysis equipment are discussed.
Tutkimuksia 162/1979, Työterveyslaitos, Laajaniityntie 1, 01620 Vantaa 62, Finland, 1979. 77p. Illus. 41 ref. Price: Fmk.20.00.
Workplace environment improvement during cleaning of castings by tool-mounted exhaust ventilation
Förbättrad arbetsmiljö vid gjutgodsrensning genom punktavsug på handverktyg [en sueco]
Description of devices developed and used with success in Sweden: power-driven hand tools with built-in exhaust ventilation (chipping hammer, cut-off grinder, straight grinder, angle grinder, suspension of tools); exhaust ventilation nozzles and their correct use; radial suspension arms with built-in valve; workplace design and layout for cleaning castings (booth, ventilation, work bench, lighting).
Rapport 790426, Svenska Gjuteriföreningen, Box 2132, 550 02 Jönköping, Sweden, no date. 29p. Illus. Price: Swe-cr.21.00.
Extract ventilation systems and their problems
Considerations on maintaining exhaust velocity at point of release of the pollutant or other substance to be captured: components of exhaust systems and their problems (suction inlets, hoods, enclosures, slots, ducts, fans, air cleaners); fume extraction units; discharge to the atmosphere; examples of faulty design, faulty installation and procedures. Other problems considered include removal of ambient heat from the workplace along with the pollutant exhausted, buoyancy factors of some pollutants, which tend to accumulate in pools on the floor or cavities in the roof, according as they are lighter or heavier than air.
Prevention, Nov. 1979, Vol.16, No.11, p.3-6. Illus.
The measurement of airflow in ducted ventilation systems.
Preventive maintenance aspects of ensuring that ventilation systems continue to function properly: checking whether the air flow rate continues to meet the parameters for which the system was designed; reasons for impaired performance (dirt on fan blades, blocked filters, corroded dampers, leaky ducting); multi-branched systems getting out of balance, some branches handling more or less air than intended; measurement of pressure differences across certain parts of the system; use of coloured smoke tracers to make airflow visible and observe flow patterns outside the system; measurement of air velocities at various points in the system. Techniques and instruments used (Pitot static tube; glass U-tube; diaphragm gauge; rotating-vane, hot-wire, thermocouple and thermister anemometers); general guidelines.
Protection, Mar. 1979, Vol.16, No.3, p.6-11. Illus.
Water-spray induced face ventilation.
Previously-used methods for preventing working face ignitions by using slower bit speeds (under 400rpm) and installation of diffuser fan systems on continuous mining machines can now be supplemented by water sprays (originally intended for methane control) used to induce face ventilation. The system was tested on a mock-up mine section. Tracer smoke representing methane was dispersed and fresh air rapidly circulated across the face by the diffuser and spray systems (2-to-1 methane reduction). Other test results: use of upper face nozzles actually deters air flow across the face; the sprays were highly successful in preventing ignitions, and reduced noise and dust. 11 guidelines are given for installation of water sprays.
American Mining Congress Journal, Sep. 1979, Vol.65, No.9, p.27-30. Illus. 4 ref.
Schläger P., Sredenscheck H.
Simultaneous use of secondary fans in underground worksites
Zusammenarbeit mehrerer Luttenlüfter [en alemán]
The use of sets of secondary fans to increase ventilation is often a source of incidents and irregular operation. The specific features of fans arranged in series or in parallel are presented. Knowledge of the characteristic pressure-volume curve of the fans is important for installation design.
Glückauf, 4 Oct. 1979, Vol.115, No.19, p.949-951. Illus.
Head I.W., Silk S.J.
Integral fume extraction in MIG/CO2 welding.
After a brief discussion of relevant aspects of the welding process, the integral exhaust system is described. The fume extraction point is mounted on the welding gun either in the form of an annular exhaust slot or a perforated extraction chamber. The exhaust flow rate is 1000-1700l/min, and a 25-38mm bore extraction hose is used. Problems of the system, which must satisfy the conflicting requirements of a non-turbulent downward flow of shielding gas and an upward and inward flow of fume to the exhaust system, are presented. Operational factors having an influence are: shape and position of work and angle of welding gun; gas flow and electrode stickout; exhaust conditions. A reduction of fume levels by up to one-third can be expected, and the effectiveness of the system is substantiated by results of atmospheric sampling.
Metal Construction, Dec. 1979, Vol.11, No.12, p.633-638. Illus. 2 ref.
Gasjuk L.A., Nonezov R.G.
Evaluation of ventilation systems on chemical fibre production machinery
Ocenka ėffektivnosti sistem ventiljacii mašin dlja proizvodstva himičeskih volokon [en ruso]
A dynamic method of testing exhaust systems under the enclosure of spinning pumps is presented. It allows the efficiency factor to be calculated and the exhaust system to be evaluated in terms of the concentration of carbon disulfide, dimethylacetamide and other toxic gases in the exhaust air. Typical concentration curves are shown for different systems operating under 2 conditions (constant exhaust, additional standby exhaust when the enclosure is opened).
Vodosnabženie i sanitarnaja tehnika, July 1979, No.7, p.26-28. Illus. 2 ref.
Dust control on bins
Obespylivanie bunkerov [en ruso]
Presentation of a method for calculating the air volume required to remove dust by exhaust ventilation when filling ore bins. Tests were carried out in industrial plants equipped with different exhaust ventilation systems: bin lid with pipe connection; exhaust truck on a crusher feed hopper, enclosed bins with cyclone chamber or turbulence exhaust fan, exhaust ventilation at skip loading and unloading openings. The enclosures reduced the workplace dust level to 2mg/m3.
Bezopasnost' truda v promyšlennosti, June 1979, No.6, p.37-38. Illus.
Bekanntmachung, Federal Ministry of Labour and Social Affairs (Bundesministerium für Arbeit und Sozialordnung), Bonn, 22 Aug. 1979.
Guidelines concerning workplaces
Arbeitsstätten-Richtlinien [en alemán]
Issued under the 1975 Ordinance concerning workplaces (CIS 75-1494) these guidelines (Oct. 1979 edition) lay down more detailed provisions for the application of art.5 (ventilation), art.10, subsection 6 (protection against doors derailing and falling), art.11, subsections 1 to 5 (automatic doors), and art.12, subsections 1 60 3 (protection against falls of persons and objects).
Bundesarbeitsblatt, Oct. 1979, No.10, p.103-108. Illus.
Elimination of harmful substances during mechanised welding processes
Udalenie vrednyh veščestv pri mehanizirovannyh vidah svarki [en ruso]
A mathematical analysis of the aerodynamic conditions to be met by local exhaust ventilation equipment for the removal of welding fume in the presence of limiting surfaces is followed by a description of an exhaust ventilation hood mounted on a welding torch for inert gas (CO2) welding. Prototype testing of this device showed the optimal diameter definition for the hood to be 70-80mm for a distance of 80mm between it and the welding point. Fume is exhausted through a flexible tube, the aerodynamic resistance of which is easy to determine. Removal efficiency is 90-95%, and saving in energy consumption is considerable compared to conventional local exhaust ventilation systems.
Sudostroenie, Mar. 1979, No.3, p.46-49. Illus. 12 ref.
Assessment of selected control technology techniques for welding fumes.
This study in an industrial MIG-welding plant validated laboratory findings on the effect of dilution air direction and velocity and use of a welding gun with built-in smoke exhaust. The studies are intended to aid updating national standards for fume control. General data on composition, sources and exposure limits of welding fumes, sampling and analysis of fumes are given, and the welding plant and equipment used for the air flow measurements are described. The maximum air flow across a weld site should not exceed 30m/min (100fp/min) at 90° to the welder and use of the "smoke-exhaust" gun is satisfactory.
DHEW (NIOSH) Publication No.79-125, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, Cincinnati, Ohio 45226, USA, Jan. 1979. 24p. Illus. 17 ref.
Fume hoods, open canopy type - their ability to capture pollutants in various environments.
Using field observations, modelling techniques, and theoretical analysis, parameters describing the performance and collection efficiency of large industrial canopy fume hoods are established for steady state collection of fume and collection of plumes with fluctuating flow rates. Suction flow rates required to capture more than 97% of the pollutant were established for various experimental conditions: hood not centrally mounted above fume source; plume subject to cross draft; a combination of these two. A baffle plate arrangement for use within hoods which prevents recirculation and spillage of fume is proposed. At a cost of US-$6 per m3/h of installed fume control system capacity, the arrangement promises to save millions of dollars on large new installations and significantly to improve the collection efficiency of existing systems. A practical application of the results to the design of electric arc furnace canopy hoods is proposed.
American Industrial Hygiene Association Journal, Feb. 1979, Vol.40, No.2, p.118-127. Illus. 5 ref.
Control of welding fume in fabrication shops.
In the light of a recent judgment of a United Kingdom Court confirming the employer's liability when TLVs for toxic substances in the workplace air have been exceeded, the article reviews the means of reducing exposure to welding fume: control of emission at source; local exhaust (well over 90% of fume emitted can be extracted by low volume-high velocity (LVHV) ventilation (capture velocity
Metal Construction, Feb. 1979, Vol.11, No.2, p.84-89. Illus. 3 ref.
Local exhaust ventilation principles.
This overview article gives the reasons for inefficient action of local exhaust systems (inadequate air volume, excessive capture distance, poor positioning of hoods). It discusses the virtues of containment, in which contaminant collection is at the very source of contamination and considers other factors important for design: conveying velocity for particulates, use of gravitational force, pressure drop in ducts, airflow distribution at hoods, fan or blower placement, installation of a static pressure gauge and tests of the system.
American Industrial Hygiene Association Journal, Jan. 1979, Vol.40, No.1, p.1-10. Illus. 19 ref.
The recirculation of industrial exhaust air
The 10 papers, and discussion, presented at this conference, 6-7 Oct. 1977, Cincinnati, Ohio, USA, are reproduced. The topics covered include the logic and procedures to evaluate the assumption, with certain restrictions, that all chemicals are potentially suitable for a given recirculation/process situation; the needs of industry and the system designer; contaminant monitoring; recirculation practices and research in Sweden.
National Institute for Occupational Safety and Health, Division of Physical Sciences and Engineering, Cincinnati, Ohio 45226, USA, Apr. 1978. 152p. Illus. 45 ref.
German Standards Institute (Deutsches Institut für Normung), Berlin (West).
Required specifications for fume cupboards
Anforderungen an Abzüge [en alemán]
Standard prescribing safety specifications based on the 1968 Act concerning technical equipment used in industry. Part 1: fume cupboards and exhaust hoods in general use in laboratories in industry, hospitals, etc.; rules for ventilation, design, piping, valves, and electrical installation. Part 2: specifications for materials for construction of special-purpose fume cupboards (corrosive acids, explosion hazards). Commentaries and list of standards to be complied with.
DIN 12 924, Parts 1 and 2, Beuth Verlag GmbH, Burggrafenstrasse 4-10, D-1000 Berlin 30, Jan. and Dec. 1978, 4+2p. Illus. Price: DM.12.60. each part.
VDI 2051, Association of German Engineers (Verein deutscher Ingenieure).
Ventilation methods in laboratories
Raumlufttechnik in Laboratorien [en alemán]
This VDI directive applies to laboratories in industry and teaching, research and hospital laboratories where harmful substances are used. The ventilation should be adequate to dilute concentrations in air of these substances and reduce them to below the corresponding TLV. The basic provisions of this directive concern: air flowrates, proportion of outside air, local exhaust ventilation at floor level, fume hoods, air inlets and outlets, fresh air purification, controlled air flow and prevention of draughts, air temperature and humidity, ventilation noise levels. A chapter is devoted to construction, constituent materials and piping for ventilation systems. Technical data concerning properties of plastics used as construction materials are shown in tables. List of pertinent DIN standards.
Beuth Verlag GmbH, Burggrafenstrasse 4-10, D-1000 Berlin 30, July 1978. 7p. Price: DM.19.60.
Ventilation at the workplace - Natural and mechanical ventilation, exhaust ventilation
Belüftung von Arbeitsräumen - Lüftung, Zuluft, Absaugung [en alemán]
Parameters for evaluation of ventilation plant are defined: air flow required for respiration and CO2 dilution, air renewal rate, temperature and relative humidity, air speed. The dilution and push-pull ventilation systems are explained with diagrams. The commonest system is dilution, the various types of which (tangential or diffuse airflow, horizontal or vertical flow, inlet and outlet at floor or ceiling level) are described.
Nr.19, Schriftenreihe Arbeitsschutz, Moderne Arbeitsstätten, Bundesanstalt für Arbeitsschutz und Unfallforschung, Postfach 17 02 02, 4600 Dortmund 17, Germany (Fed.Rep.), 1978, p.93-125. Illus.
Exhaust of harmful substances
Schadstofferfassung [en alemán]
This book provides designers with the main facts concerning exhaust ventilation systems. Contents: terms and definitions; legislation in the German Democratic Republic; possibilities of reducing concentrations of harmful substances (increased air exchange rate, workplace design, exhaust ventilation at the source); theory (collection systems, thermal upcurrents, transport of harmful substances to the exhaust by directed air stream, indicative values for collection velocity).
VEB Verlag Technik, Oranienburgerstrasse 13-14, DDR-1020 Berlin, 1978. 129p. Illus. 86 ref.
Device for controlling the concentration of toxic gases
Ustrojstvo dlja regulirovanija koncentracii jadovityh gazov [en ruso]
An air-conditioning installation for cattle sheds and poultry farms which automatically regulates air temperature and humidity has been equipped with a gas analyser which, by means of a relay, switches on ventilation fans as soon as the atmospheric concentration of ammonia in the premises exceeds the displayed threshold. Description of the regulatory system which includes safety relays to prevent excessive lowering of the air temperature, and an acoustic warning signal which sounds if the threshold concentration is considerably exceeded. The electrical system is reproduced, together with the equations used for calculating the values to be regulated and a graph illustrating the response of the regulator. The principle described can be applied to other toxic gases.
Mehanizacija i ėlektrifikacija socialističeskogo sel'skogo hozjajstva, Dec. 1978, No.12, p.46-48. Illus. 3 ref.
Determination of collection efficiency - Particle size distributions and concentrations during welding with and without different local exhausts, and performance of some collectors and ventilation systems
Bestämning av infångningsförmåga - Partikelstorleksfördelningar och -koncentrationer vid svetsning med och utan olika punktutsug samt funktion hos några avskiljare och ventilationssystem [en sueco]
Collection efficiencies were determined for 15 different types of local exhausts. The air flows were 40-1000m3/h. 7 of the exhausts were tested with 2 air flows and in different locations. The tests were carried out in an air-conditioned room with constant particle concentration. Different electrodes were used, and the particle numbers were determined with and without exhaust in 10 size stages from 0.01 to 1µm and in 5 stages from 0.5 to 10µm. The collection efficiencies for arc welding were 97-99% for particles 0.1-1.4µm, but were lower for shielded-arc welding. Exhausts or welding guns had 70-90% efficiencies. The flow rates for these exhausts were limited by shielding gas requirements. There was a slight tendency for increasing efficiency with increasing particle size. 3 welding workshops with different air inlet systems had particle concentrations and size distributions similar to the test room without local exhaust. 5 welding fume filters gave increasing efficiencies with increasing particle size; efficiencies ranged from 86-99.99% for particles 0.1-0.18µm to 99.0-99.99% for particles 0.56-1.0µm.
Arbete och hälsa - Vetenskaplig skriftserie 1978:18, Arbetarskyddsverket, Fack, 100 26 Stockholm, Sweden, Oct. 1978. 86p. Illus. 11 ref.
Exhaust ventilation in the woodworking industry
L'aspiration dans les industries du bois. [en francés]
Fire safety and housekeeping requirements in woodworking shops necessitate the installation of efficient exhaust systems for sawdust removal. This booklet reviews the basic aspects of aerodynamics and examines the present day state of the art regarding various exhaust ventilation systems for the removal of sawdust and wood chips, and their performance (fans, exhaust ducts and hoods, dust collectors). A section devoted to storage bins considers fire hazards in the industry and arching of bulk materials. Other chapters deal with exhaust ventilation systems (with concrete examples) and equipment required for exhaust removal of small-size particles.
Cahier 110, Centre technique du bois, 10 avenue de Saint-Mandé, 75012 Paris, France, Dec. 1978. 91p. Illus.
Kazakov V.K., Avramenko A.F.
Cutting tool with built-in exhaust for dust removal
Pyleotsasyvajuščij rezec [en ruso]
Brief description, with detailed drawings, of a lathe tool with a built-in local exhaust nozzle, for machining friable materials such as fabric-base laminated plastics, asbestos cement, glass fibre-reinforced plastics, etc.
Mašinostroitel', Dec. 1978, No.12, p.13. Illus.
Flat convection currents at the surface of open high-temperature baths for industrial treatment
Płaskie strumienie konwekcyjne nad odkrytymi powierzchniami gorących kąpieli technologicznych [en polonés]
Aerodynamic measurements taken on the basis of formulae proposed in the literature, to determine the air velocity distribution in convection currents formed on the surface of baths at temperatures well above that of the ambient air, are described in an attempt to obtain data for ventilation design. The results confirmed the practical value of the formulae used and demonstrated the need to extract a greater volume of air from the centre than from the edges of the bath. The air volume extracted should be proportional to the distribution of air velocities in the convection current. Local exhaust systems should thus provide for air flow regulation the whole length of the baths.
Prace Centralnego instytutu ochrony pracy, 1978, Vol.28, No.99, p.373-388. Illus. 9 ref.
Influence of disturbing currents on local exhaust ventilation systems
Wpływ strumieni zakłócających na skuteczność działania ssawek urządzeń wentylacji miejscowej [en polonés]
Design of exhaust hoods is an important factor in the collection of pollutants close to the source. A classification of mobile hoods used in welding is presented, and a method and a test set up especially designed for study of the influence of disturbing currents on the air velocity distribution in the range of action of the hood are described. Using isotachs the changes caused by disturbances are shown. The results confirmed the usefulness of the method, especially for studying small hoods. Further research to determine "exhaust spectra" of hoods is proposed to give designers a more solid basis for increasing the efficiency of ventilation systems.
Prace Centralnego instytutu ochrony pracy, 1978, Vol.28, No.96, p.45-60. Illus. 17 ref.
Liszka L., Danielsson A., Söderberg L., Lindmark A.
Research on the chronic effects of ventilation noise on man
En undersökning av långtidseffekter av ventilationsbuller på människor [en sueco]
Results of research carried out in a workplace where 54 workers were exposed to airflow noise (<92dB) over periods varying between 3 and 10 years. The sound spectrum included a large percentage of low frequencies and infrasound. Even slight noise levels had an effect on the arterial blood pressure. The authors were able to establish a significant relation between the noise level and a reduction of arterial blood pressure. They observed that the less-exposed workers used less pharmaceutical products than those exposed to louder noise. Monitoring of urinary catecholamine in the exposed workers showed relatively low levels and normal variations between periods of work and rest, showing the absence of any specific workpost stress.
Undersöksningsrapport 1978:34, Arbetarskyddsstyrelsen, Fack, 100 26 Stockholm, Sweden, 1978. 27p. Illus. 1 ref. Price: Swe-cr.10.00.
Exhaust and collection of fumes from die-casting machines
Absaugung und Abscheidung der Dämpfe an Druckgiessmaschinen [en alemán]
Parting agents used in die-casting machines are the main source of air pollution in these foundries, and it must be controlled at the source by exhaust ventilation. The operation and construction of these installations is described: suction effect, volume of exhaust air, example of an exhaust system serving several machines. Fume collection as close as posssible to the source is decisive for efficiency. Attention is drawn to the high fire risk associated with condensation of grease in the pipework. Filtration of the fumes is also dealt with, with illustrated descriptions of the various mechanisms and types of filter.
Giesserei, 14 Sep. 1978, Vol.65, No.19, p.510-515. Illus. 5 ref.
Underground use of dust scrubbers.
This article surveys recent developments in wet dust collectors and a new compact dry dust collector for use in underground coal mines. The aspects of efficiency of removal of dust-laden air from the face area are studied, comparing conditions in the USA and in Europe. The article considers the use of a dust collecting enclosure or hood on a rotary crusher and on a conveyor belt transfer point and describes a dust collector arrangement for a tunnel boring machine. The inferiority of dry collectors (filter and cyclone types) underground is emphasised and the test findings on a wet dust collector recently developed in West Germany are given, stressing the adjuvant role of turbulence in the collector in the wetting of particles and illustrating the principle of a horizontal centrifugal separator for separating dust-laden micro-droplets from the air flow. The author claims that high-pressure wet collector systems have 99.99% efficiency. A prototype dry dust collector with a specially impregnated tough filter fabric, currently being tested, is described.
American Mining Congress Journal, Mar. 1978, Vol.64, No.3, p.46-49. Illus.
Effect of flanges on the velocity in front of exhaust ventilation hoods.
Addition of a flange to a local exhaust ventilation hood can produce a large increase in air velocity in front of the hood, An optimum flange width exists - the square root of the slot area - beyond which there is little further increase in exhaust air velocity. The effect of flanges increases in proportion to the aspect ratio of the hood. The addition of even small flanges can have an appreciable effect. Velocity increases exceeding 55% have been measured in front of hoods with an aspect ratio of 16:1.
Annals of Occupational Hygiene, Dec. 1978, Vol.21, No.3, p.265-269. 4 ref.
Grimitlin M.I., Zabavskij A.N., Grimitlin A.M.
Adjustable air outlet for workplace ventilation in shipyards
Reguliruemyj vozduhoraspredelitel' dlja podači vozduha v sudostroitel'nye cehi [en ruso]
Description of an adjustable air outlet designed for ventilating disseminated workposts which have to be constantly moved in shipyards. The outlet expander and the guide vanes are designed so as to reduce pressure drop (and loss of temperature in the case of air heating systems) to a minimum. The adjustable guide vanes enable the air stream to be directed at any angle between +45° and -45° in relation to the axis of the outlet; the velocity of the air stream remains constant on account of the low aerodynamic resistance of the guide vanes.
Sudostroenie, Sep. 1978, No.9, p.49-51. Illus.
Mixed general ventilation of multibay factories with heavy heat production
Smešannaja obščeobmennaja ventiljacija mnogoproletnyh cehov so značitel'nymi teplovydelenijami [en ruso]
Results are reported of theoretical and experimental studies of natural and mixed ventilation of industrial buildings containing furnaces. A formula for determination of temperature at the workplace (based on the flow of hot air, and natural and mechanical ventilation air) and a calculation method for mixed general ventilation of multibay factories, are developed. Model studies to optimise air renewal have shown that each bay must be provided with mechanical ventilation inlets located slightly above floor level, in addition to skylights.
Vodosnabženie i sanitarnaja tehnika, Aug. 1978, No.8, p.6-10. Illus. 5 ref.
Measures to prevent smoke from fire outbreaks from entering emergency exits
Massnahmen zum Schutz der Rettungswege gegen Rauchgaseintritt [en alemán]
The exchange between smoke escaping from premises on fire and fresh air from neighbouring premises plays an important role in the spread of fires, and affects the extent to which the neighbouring premises can be used as emergency exits. The volume of flow of smoke is caused by differences in pressure arising between the 2 premises on account of the difference in temperature. This article studies these differences and the physical laws on which they are based, and calculates the flow volume of fresh air required to prevent smoke escaping from burning premises.
VFDB-Zeitschrift, 1978, Vol.27, No.1, p.34-36, and No.2, p.56-58. Illus. 2 ref.
Industrial ventilation and atmospheric pollution control
Promyšlennaja ventiljacija i zaščita vozdušnoj sredy [en ruso]
Series of articles on: calculation of zone ventilation of workplaces; calculation of coefficient of non-isothermal conditions for studies of air heating; studies and calculation of draughts; design of rectangular air inlets; temperature distribution in multi-bay air-conditioned halls; ventilation of such halls in the event of heavy heat production; efficacy of rim-exhaust systems with provision of make-up air; efficacy of natural ventilation of an industrial complex; model study of natural ventilation of factories; pollutant concentration distribution around industrial buildings; cleaning of gas emissions; exhaust ventilation device for machine-tools; measurement and calculation of air flow in circular or rectangular ducting; influence of surface roughness of ventilation ducts.
Vsesojuznyj central'nyj naučno-issledovatel'skij institut ohrany truda VCSPS, Obolenskij per. 10, Moskva, USSR, 1978. 204p. Illus. 131 ref. Price: Rbl.1.00.
Lead dust control in the accumulator industry: Good ventilation and personal hygiene
Ackumulatorindustri bekämpar blydamm: God ventilation och personlig renlighet [en sueco]
This article describes lead dust control measures adopted in a Swedish storage battery factory: melting, oxidation, handling and storage of lead oxide; mixing of paste and pressing it into the grids; drying operations etc.) ventilation (the exhausted air is purified in wet dust collectors and is not recirculated; the air conditioning is shut off outside working hours, to avoid unnecessary stirring up of dust); local exhaust ventilation and vacuum cleaners are used to remove deposited dust; personnel are required to wear rubber gloves, protective clothing, dust masks, etc.; work clothes must be changed daily and a daily shower taken; regular blood tests of exposed workers and transfer to other work if blood lead levels exceed 60µg/100ml.
Arbetsmiljö, 1978, No.10, p.11-13. Illus.
Partridge L.J., Nayak P.R., Stricoff R.S., Hagopian J.H.
A recommended approach to recirculation of exhaust air.
The factors to be considered in the design, installation and operation of a recirculation system are reviewed and discussed in this research report. The variables are: overall design; feasibility assessment; contaminant properties; exhaust cleaning; surveillance and response systems; recirculation system design; performance evaluation; maintenance and operation. The appendices, which embody the conclusions of the report, show modeling of a system, equations and calculations for the configurations, and a hypothetical system for vapour degreasing.
DHEW (NIOSH) Publication No.78-124, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, Cincinnati, Ohio 45226, USA, Jan. 1978. 184p. Illus.
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