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PubMedDate not supplied

Welding and ischemic heart disease.

Metal welding and cutting are associated with inhalation of gases and respirable particles. The purpose of this study was to compare the mortality of male welders with that of all gainfully employed men in Sweden regarding ischemic heart disease (IHD). Male welders and gas cutters were identified in the Swedish National Censuses of 1970 and 1990. Two cohorts were established and followed until the end of 1995. The IHD mortality among the welders was compared with that of all gainfully employed men. An increased mortality due to IHD was observed among welders identified in the 1990 Census, SMR = 1.35, 95% confidence limits 1.1-1.6. The observed increased mortality due to IHD was unlikely to be explained by different smoking habits. A general hypothesis linking inhalation of particles to the occurrence of IHD via an inflammatory process is discussed.

Adult↗
PubMed1998

Occupational exposure to dioxins by thermal oxygen cutting, welding, and soldering of metals.

This paper focuses on one aspect of occupational dioxin exposure that is novel and unexpected. Exposures in excess of the German threshold limit value of 50 pg international toxicity equivalent (I-TEQ)/m3 are very frequent, unpredictable, and sometimes very high--up to 6612 pg I-TEQ/m3--during thermal oxygen cutting at scrap metal and demolition sites. The same procedure involving virgin steel in steel trade and mass production of steel objects gave no such evidence, even though no final conclusions can be drawn because of the low number of samples analyzed. Low dioxin exposures during inert gas electric arc welding confirm previous literature findings, whereas soldering and thermal oxygen cutting in the presence of polyvinyl chloride give rise to concern. The consequences of occupational dioxin exposure were studied by analysis of the dioxin-blood concentration, the body burden, of men performing thermal oxygen cutting at scrap metal reclamation and demolition sites, in steel trade and producing plants as well as for industrial welders and white-collar workers. The results concerning body burdens are in excellent agreement with the dioxin exposure as characterized by dioxin air concentration in the workplace. The significant positive correlation between duration and frequency of performing thermal oxygen cutting at metal reclamation and demolition sites expressed in job-years and dioxin body burden speaks for the occupational origin of the observed overload after long times. The results reported here lead to consequences for occupational health, which are discussed and require immediate attention.

Adult↗
PubMed1991

Pulmonary reactions caused by welding-induced decomposed trichloroethylene.

This is the report of a welder who performed argon-shielded electric arc welding in an atmosphere containing trichloroethylene. He developed immediate respiratory symptoms, pulmonary edema 12 hours after exposure, and recurring dyspnea ten days after exposure. These pulmonary reactions might be explained by inhalation of decomposition products of trichloroethylene such as dichloroacetyl chloride and phosgene.

Dyspnea↗
PubMed2002

Correlations between workplace protection factors and fit factors for filtering facepieces in the welding workplace.

Workplace protection factor (WPF) means a measure of the actual protection of respirator provided in the workplace when correctly worn. While fit factor (FF) represents a quantitative measure of the fit of a particular respirator to an individual and it is determined in the laboratory. To evaluate the relationship between WPF and FF is very important since FF may or may not be taken advantage of estimating WPF. Outside and inside Fe concentrations for three brand N95 filtering facepieces were collected on 14 workers/three respirator combinations in the welding workplace. The WPF measurements on the samples of the three respirator brands worn by 14 workers were observed to range from 2.2 to 132.9 with a geometric mean of 15.9 and a geometric standard deviation of 2.63. Respirator performances as measured by the WPF differed significantly among different respirator brands (p<0.05). In this study, correlations were found between the WPF measurements and the FF data for all samples of the three respirators (R2=0.38). The percentage of Fe particles having a smaller fraction than 1.1 microm diameter was observed as 71.6% of the total.

Filtration↗
PubMed1987

Electrical activity in dental amalgam of submerged divers during welding.

Divers performing underwater manual metal arc welding/cutting (UMMA) have complained about a metallic taste phenomenon. In several dives with voluntary leakage in their diving suits, potential alterations in dental amalgam were registered when they performed UMMA. Polarization resistance values were obtained for the test amalgam cylinders used and the diver's dental restorations. These values, along with the recorded potential values of the amalgam test cylinders and of the diver's dental restorations, enabled us to calculate the depolarizing current, using the law of Ohm. The current depolarizing the amalgam test cylinder did not differ significantly from the mean intermetallic currents between the dental restorations. The clinical effect of intraoral currents when performing UMMA welding should be regarded as small, whereas considerably higher currents should not be ruled out in an intense cutting situation.

Adult↗
PubMed1987

Fracture of hip prostheses due to inadequate welding.

Twenty-five patients underwent total hip arthroplasty using a copy of a well-known prosthesis during the period 1974-1976. Five of the prostheses fractured through the neck after 5-12 years. There were no prodromal symptoms and no trauma preceded the fractures. Technical analysis revealed that inadequate welds were responsible.

Aged↗
PubMed1995

[Measurement of airborne fumes in welding factories].

Concentrations and size distributions of airborne welding fumes in work environments were measured. Samples were collected from 20 workplaces in 13 companies. In all workplaces, the stationary samplings including A-sampling and B-sampling and the personal sampling were carried out simultaneously. The fume concentration in the stationary sampling was measured with a digital dust monitor. A low volume air sampler and an Anderson cascade impactor was also used to determine the conversion factor of the values obtained by the digital dust monitor and the size distributions of the fumes. The personal exposure levels were measured with a TR sampler and a personal cascade impactor. The concentrations by the personal sampling (average: 11.3mg/m3) were much higher than those by the A-sampling (average: 0.4mg/m3 and range: 0.15-0.64mg/m3) but lower than those by the B-sampling (average: 46.8mg/m3, range: 0.66-152.8mg/m3). The mass median aerodynamic diameter (MMAD) of the stationary and the personal samplings were 2.41 microns and 0.80 microns, respectively. Fumes were observed under a scanning electron microscope. Most of the fume particles were sphere in shape but smaller fumes were aggregated and formed larger secondary particles.

Dust↗
PubMed2000

[Titanium joints welded with laser and infrared techniques: comparative analysis of its microstructure].

BACKGROUND: Aim of the study is to compare microstructure of Titanium joints soldered with Laser and Infrared methods by performing SEM analysis, metallography and microhardness evaluation. METHODS: Wax specimens were separated in the middle area corresponding to the joint region, machined and then soldered. 40 Titanium samples were fused and divided in 2 groups of 20 samples each. First group was soldered by laser welding, second one by infrared brazing. SEM analysis and standard metallography were carried out at joined areas and unsoldered surfaces. Microhardness test was performed on longitudinally sectioned samples with 150 g load for 15 second up to 7 mm distance from the joined area. RESULTS: SEM photomicrographs revealed for group 1 a homogeneous metal-joint interface, without microporosities; for group 2 exhibited a distinct demarcation of metal joint interface. Metallography evaluation showed for laser joined samples only the presence of Titanium; infrared joined samples showed in soldered regions also Ni and Cu. Microhardness values detected at the joined surfaces seem to be higher for both considered groups. CONCLUSIONS: Laser joining method with exclusive presence of Titanium seems to be ideal for monometallism; both techniques exhibited microstructural changes in the heated surface layer.

Hardness Tests↗
PubMed2001

Laser welding of thermoplastic materials.

The capabilities of the three main types of laser are compared and a new technique is introduced, which laser welds plastics using an infrared absorber to create a joint that is almost invisible to the human eye.

Humans↗
PubMed1992

Fixed implant-supported prostheses with welded titanium frameworks.

Eighty-six edentulous patients provided with Brånemark implants were randomly selected for fixed prostheses with modified framework designs. This study describes alternative laboratory techniques in which premachined titanium components are welded together to form the framework. Clinical experience, following the patients for 1 year after placement, indicates that it is a predictable technique with a similar pattern of complications as experienced by patients with cast frameworks supported by implants. The prostheses are considered to be slightly more bulky than cast frameworks, but seem to have, on a clinical level, a better fit to the implants.

Adult↗
PubMed1992

[Expression of TNF-alpha in alveolar macrophages after stimulation with quartz dust, welding fume dust and asbestos fibers].

Alveolar macrophages have a potential for expressing and excreting many factors that are immunologically active and active on cytokines (monokines and lymphokines) and are thus indirectly involved in the genesis of pulmonary fibroses. One of these factors is the tumour necrosis factor alpha (TNF alpha). In the study presented here, the expression of TNF alpha-mRNA was investigated in macrophages stimulated in vitro with quartz dust, dust from cinders of welding furnaces, and asbestos, using non-radioactive in situ hybridization. There was a marked dependence of the expression of this cytokine on both time and stimulation. Macrophages stimulated by quartz dust showed the highest rate of expression compared with controls and other related stimuli. In addition, all stimuli yielded an expression that was elevated for a short period only and reached its peak after four hours. The results permit the conclusion that various professionally inhaled dusts possess different risk potentials in respect of lung damage mediated by macrophages and do not behave uniformly.

Animals↗
PubMed2000

High-frequency welding trials.

The high-frequency weldability of a new family of polyolefin films is compared with that of conventional films made of other polymers. A comparison of the optimum weld parameters of all the films and the results of performance testing of all the pouches produced are reported.

Alkenes↗
PubMed1990

[Ultraviolet exposure in the environment of welding work sites].

It has been checked if the "limits of the acceptable doses of ultraviolet radiation of monochromatic radiation at the workplace" (NIOSH-standard of USA) are adhered to in the vicinity of welders' work stations in a factory hall. For recording of UV-doses polysulphon films have been used. According to these investigations non-welders are exposed to doses of UV-radiation which exceed the limits recommended by about eight times. Clinical examinations of these persons showed chronic damage of the external parts of the eyes in a higher percentage than in a control group. It is pointed to the necessity of taking protective measures to shield persons working in the vicinity of welding job sites from ultraviolet radiation.

Dose-Response Relationship, Radiation↗