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At least 19 recordsLinked to original sources
PubMed2000

Laboratory evaluation of welder's exposure and efficiency of air duct ventilation for welding work in a confined space.

CO2 arc welding in a confined space was simulated in a laboratory by manipulating a welding robot which worked in a small chamber to experimentally evaluate the welder's exposure to welding fumes, ozone and carbon monoxide (CO). The effects of the welding arc on the air temperature rise and oxygen (O2) concentration in the chamber were also investigated. The measuring points for these items were located in the presumed breathing zone of a welder in a confined space. The time averaged concentrations of welding fumes, ozone and CO during the arcing time were 83.55 mg/m3, 0.203 ppm and 0.006%, respectively, at a welding current of 120A-200A. These results suggest serious exposure of a welder who operates in a confined space. Air temperature in the chamber rose remarkably due to the arc heat and the increase in the welding current. No clear decrease in the O2 concentration in the chamber was recognized during this welding operation. A model of air duct ventilation was constructed in the small chamber to investigate the strategy of effective ventilation for hazardous welding contaminants in a confined space. With this model we examined ventilation efficiency with a flow rate of 1.08-1.80 m3/min (ventilation rate for 0.40-0.67 air exchanges per minute) in the chamber, and proved that the exposure level was not drastically reduced during arcing time by this air duct ventilation, but the residual contaminants were rapidly exhausted after the welding operation.

Carbon Dioxide↗
PubMed2004

Finding the right approach. What do you mean, this is a non-permit required confined space?

While not a big fan of the non-permit confined space designation, I have come to believe the approach can work if done properly. However, it is this author's opinion that the designation of a confined space as non-permit required in any work environment should be the exception rather than the rule. The up-front determination that a space is "non-permit-required" should necessarily consume more time and resources than assuming the space is "permit-required" because so fewer controls are in place. Most certainly, this decision must be based on the knowledge that no hazards are present or have the potential to develop, rather than on "convenience" or "resource limitations"; assumptions should never play a part in the decision. Attention to proper evaluation of confined spaces, documentation of actual conditions over time, and communication to those entering the spaces are all critical components of a safe confined space entry program, whether the space be permit-required or not.

Guideline Adherence↗
PubMed1986

Confined spaces--a case for ventilation.

Many exposures, some leading to deaths and injuries, in confined spaces could have been prevented by ventilating the space prior to and during the entry. Current standards and guidelines generally do not require ventilation. Nor do they sufficiently emphasize the need for ventilation or provide guidance on how to ventilate confined spaces. Mechanical ventilation is a positive engineering control action that can usually be taken and that will reduce the hazards of adverse atmospheric conditions inside a confined space. Natural ventilation usually is not sufficiently reliable to serve as a primary means of control. Unfortunately, very little specific information is available for designing and implementing ventilation strategies for confined spaces. More published information is needed, such as examples of effective policy and procedures in use by industry and findings from research on confined space ventilation. Basic and applied research can help to demonstrate effective ventilation actions and develop useful design guidelines. Additional published information should increase hazard awareness and reduce the likelihood of accidents.

Industry↗
PubMed2000

Confined space synthesis. A novel route to nanosized zeolites.

Confined space synthesis is a novel method in zeolite synthesis. It involves crystallization of the zeolite inside the pore system of an inert mesoporous matrix. In this way it is possible to prepare nanosized zeolites with a controlled size distribution by proper choice of the inert matrix. Here, confined space synthesis was adopted to prepare nanosized ZSM-5, zeolite Beta, zeolite X, and zeolite A with tailored crystal size distributions using mesoporous carbon blacks as inert matrices. All zeolites were characterized by X-ray powder diffraction, transmission electron microscopy, and nitrogen adsorption/desorption prior to and after removal of the carbon matrix. ZSM-5 with Si/Al ratios of 50, 100, and infinity (silicalite-1) were synthesized with controlled average crystal sizes in the range 20-75 nm. Nanosized zeolite Beta (7-30 nm), zeolite X (22-60 nm), and zeolite A (25-37 nm) were prepared similarly. Removal of the carbon matrix by controlled combustion allows a convenient method for isolation of the pure and highly crystalline zeolites. Therefore, confined space synthesis appears to be an attractive method for preparation of zeolites with a controlled size distribution.

Journal Article↗
PubMed1989

The confined space. A review of a recently discerned medical entity.

This paper presents an extensive review of the literature relating to the industrial confined space. It defines the various types of confined spaces, classifies their associated noxious atmospheres, and identifies the potential hazards of each. A newly recognized confined space, the environment of the surgical amphitheater in which the surgical patient undergoes general anesthesia, has been added. Pathological alterations bearing upon these hazards and the forensic principles of confined space injuries are examined in depth. In addition, recent methods are described for prevention and control of the perils of the confined space.

Accidents, Occupational↗
PubMed1964

PENETRATION BY GASES TO STERILIZE INTERIOR SURFACES OF CONFINED SPACES.

The rate of penetration of gaseous sterilizing agents into confined spaces can be predicted from physical and chemical considerations. The exposure times required to obtain sterilizing concentrations of ethylene oxide in several configurations of confined space were predicted by computation and illustrated by experiment. The results of the computations are presented graphically.

Bacillus subtilis↗
PubMed1992

Confined space fatalities in Virginia.

To better understand the frequency and characteristics of occupational confined space fatalities in Virginia, we reviewed death certificates, workers' compensation files, a Virginia Occupational Safety and Health Administration listing, and medical examiner records for all 50 fatalities (41 accidents) reported during 1979 to 1986. All fatalities were identified in medical examiner records (50), more than in any other source. The majority of decedents were male craftsmen, operators, or laborers less than 50 years old (mean 38). Drug screens of the 43 decedents tested were negative, with the exception of 2 cases where blood alcohol was detected (greater than or equal to 0.06%). Approximately 5% of "at work" civilian deaths (excluding plane, train, and motor vehicle fatalities) were confined space related. Virginia resident death rates per million employees were highest for shipbuilding and repair facilities (23.2), local government (8.9), and manufacturing other than shipbuilding (5.4%). Multiple fatalities occurred in 4 (10%) of the accidents, with 3 involving 2 fatalities each, and 1 accident involving 7 fatalities. Three fatalities (6%) were rescuers. Fifty nonfatal injuries of rescuers were known to have occurred in these accidents, 15 of co-workers and 35 of community rescue personnel (firefighters and rescue squad members). Approximately half the accidents occurred during the fourth quarter of the year and on a Thursday or Friday, and about one third occurred at night. The leading accident type was atmospheric condition, most commonly oxygen deficiency (33%) or the presence of carbon monoxide (20%). In 6 (40%) of the 15 accidents involving atmospheric condition, the toxic gas or oxygen deficiency was absent in the confined space at the time of entry.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidental Falls↗
PubMed2005

Understanding and measuring powered wheelchair mobility and manoeuvrability. Part I. Reach in confined spaces.

PURPOSE: To determine: (1) what wheelchair manoeuvrability factors are important and (2) the effects of powered wheelchair design on the ability to reach in a confined space. METHOD: The relative importance of five aspects of wheelchair manoeuvrability was determined through a survey of users of wheelchairs (N = 52) and health care professionals and others (N = 89). A single young, non-disabled subject undertook repeated trials of reach distance on to a counter at the end of a corridor whose width could be adjusted by moving Styrofoam walls. RESULTS: Reaching, moving in confined spaces and avoiding collisions were more important than speed and avoiding the need to drive backwards. The rear wheel drive powered wheelchair was found to allow the greatest reach when driving backwards into the space and the wheelchair which moved in a sideways direction allowed greatest reach in the narrowest corridor. CONCLUSIONS: The survey concluded that manoeuvring in small spaces and reaching without collisions were important. The powered wheelchair with sideways capability afforded the greatest reach in confined spaces except when the rear wheel drive chair was driven in backwards. The survey respondents did not place a high priority on avoiding backwards driving but some people find this difficult to do safely.

Comprehension↗
PubMed1995

Confined space hazards: combined exposure to styrene, fiberglass, and silica.

Work in confined spaces continues to present hazards to workers. The magnitude of this problem was recently addressed by the Occupational Safety and Health Administration in its Final Rule for "Permit-Required Control Spaces for General Industry" (29 CFR Parts 1910). Although illness and injury are typically due to asphyxiation, explosion, and drowning, toxic exposures also are an important risk. We describe herein four workers engaged in erosion-proofing enclosed chemical tanks with minimal ventilation and no respiratory protection. They were exposed to styrene-based solvents, styrene-based resins, silica, and fiberglass dust. Each experienced acute neurological effects and bronchitis. One worker developed a life-threatening pneumonia that resulted in numerous complications. The severity of the illness, which would likely not have otherwise occurred, resulted from impaired lung defense mechanisms due to the combined exposures. Several studies support the association of styrene exposure and respiratory illness that may be compounded by co-exposure to fiberglass in unique circumstances. To prevent the hazards of confined space, recommended procedures should be followed, including those established by the National Institute for Occupational Safety and Health and the Occupational Safety and Health Administration.

Adult↗
PubMed1993

Permit-required confined spaces.

The focus of the new Occupational Safety and Health Administration Standard: Permit-Required Confined Spaces (29 CFR 1910.146) is to protect workers who enter and work in areas with immediate health or safety risk from toxic, explosive, and/or asphyxiating atmospheres. The rule mandates that employers identify all permit-required confined spaces in their workplaces, prevent unauthorized entry into them, and develop a program to protect workers during authorized entry. Included in this standard are requirements for the content, issuance, and retention of entry permits; the provision of standby attendants; arrangements for rescue and other emergency services; the communication of hazards to workers (including contractors' employees); and appropriate training and equipment for authorized entrants, attendants, and entry supervisors.

Air↗
PubMed2006

Anisotropic siloxane-based monolith prepared in confined spaces.

When bicontinuous gels are prepared via sol-gel method in a 2-dimensionally (2D) confined space, the gel skeletons in the vicinity of interface of a mold are elongated perpendicular to the interface. This phenomenon was attributed to the dynamic wetting of polymerizing siloxane phase onto the interface of the mold under gravity. In this paper, we report the successful preparation of monolithic columns with an oriented pillar structure in a variety of 2D confined spaces. Starting from a solution, which consists of methyltrimethoxysilane (MTMS), the macroporous structure is prepared in situ by a completely spontaneous process. In the oriented pillar structure, bicontinuous siloxane skeletons deformed or disappeared and most pillars are oriented along the direction of gravity. Gel morphologies with the pillar structure were examined by scanning electron microscopy (SEM) and laser scanning confocal microscopy (LSCM). Geometrical information on gel morphologies was numerically derived from the obtained 3D LSCM images.

Acetamides↗
PubMed1981

Monitoring personnel exposure to stainless steel welding fumes in confined spaces at a petrochemical plant.

This paper documents exposure to stainless steel welding fumes at a petrochemical plant. The situation evaluated may be separated into three categories: 1) evaluation of background concentration levels in a maintenance shop (area monitoring), 2) evaluation of personnel exposures during open air welding in a maintenance shop (personal monitoring), 3) evaluation of personnel exposures in confined space welding (personal monitoring). Thirty-five area samples and seventy-six personal samples were collected and analyzed for chromium (VI), total chromium, nickel, iron, copper, and total particulates. The background concentrations in the maintenance shop were found to be far below those felt to be harmful. Personnel exposures found in the maintenance shop during open air welding were also low, especially when compared to current OSHA permissible exposure levels. Contaminant levels found during confined space welding, as in distillation towers, were considered excessive. After several possible solutions to the problem were considered, it was decided to implement a mandatory air-line respirator program for all employees entering confined spaces during stainless steel welding operations.

Air Pollutants↗
PubMed1996

Blast injuries: bus versus open-air bombings--a comparative study of injuries in survivors of open-air versus confined-space explosions.

OBJECTIVES: To compare injury patterns resulting from explosions in the open air versus within confined spaces. METHODS: Medical charts of 297 victims of four bombing events were analyzed. Two explosions occurred in the open air and two inside buses. Similar explosive devices were applied in all four incidents. The incidence of primary blast injuries, significant penetrating trauma (Abbreviated Injury Scale score > or = 2), burns, Injury Severity Score, Revised Trauma Score, and mortality were compared between the two populations. RESULTS: A total of 204 casualties were involved in open-air bombings, 15 of whom died (7.8%). Ninety-three victims were involved in bus bombings, 46 of whom died (49%). The difference in mortality rate was highly significant, p < 0.00001. Primary blast injuries were observed in 25 and 31 victims (34.2% and 77.5% of admitted victims), respectively (p = 0.00003). Median Injury Severity Score was 4 versus 18, respectively (p < 0.0001). CONCLUSION: Explosions in confined spaces are associated with a higher incidence of primary blast injuries, with more severe injuries and with a higher mortality rate in comparison with explosions in the open air.

Adolescent↗
PubMed1997

Effects of reduced oxygen partial pressure on cognitive performance in confined spaces.

The reduction of oxygen levels is a technique used both for fire fighting and fire protection in confined spaces. The purpose of this study was to find out if and how reduced oxygen levels affect cognitive performance in a small group of persons living in a confined space such as a submarine. In 3 separate experiments lasting for 11 to 14 days, a total of 22 men were exposed to normoxic and different levels of hypoxic normobaric atmospheres (15, 14, and 13 kPa O2). Each participant completed a cognitive test battery twice every 24-hr period in the first 2 experiments, but only once a day in the 3rd experiment. Performance in almost all tests improved with the number of test sessions performed, despite reductions of the oxygen partial pressure. Under the conditions tested, cognitive performance decrements could not be observed if inspiratory oxygen partial pressure was kept above 13 kPa.

Adult↗
PubMed2004

Geometry effects in confined space.

In this paper we calculate some exact solutions of the grand partition functions for quantum gases in confined space, such as ideal gases in two- and three-dimensional boxes, in tubes, in annular containers, on the lateral surface of cylinders, and photon gases in three-dimensional boxes. Based on these exact solutions, which, of course, contain the complete information about the system, we discuss the geometry effect which is neglected in the calculation with the thermodynamic limit V--> infinity, and analyze the validity of the quantum statistical method which can be used to calculate the geometry effect on ideal quantum gases confined in two-dimensional irregular containers. We also calculate the grand partition function for phonon gases in confined space. Finally, we discuss the geometry effects in realistic systems.

Journal Article↗
PubMed2006

Dose-effect relationships between manganese exposure and neurological, neuropsychological and pulmonary function in confined space bridge welders.

BACKGROUND: Although adverse neuropsychological and neurological health effects are well known among workers with high manganese (Mn) exposures in mining, ore-processing and ferroalloy production, the risks among welders with lower exposures are less well understood. METHODS: Confined space welding in construction of a new span of the San Francisco-Oakland Bay Bridge without adequate protection was studied using a multidisciplinary method to identify the dose-effect relationship between adverse health effects and Mn in air or whole blood. Bridge welders (n = 43) with little or no personal protection equipment and exposed to a welding fume containing Mn, were administered neurological, neuropsychological, neurophysiological and pulmonary tests. Outcome variables were analysed in relation to whole blood Mn (MnB) and a Cumulative Exposure Index (CEI) based on Mn-air, duration and type of welding. Welders performed a mean of 16.5 months of welding on the bridge, were on average 43.8 years of age and had on average 12.6 years of education. RESULTS: The mean time weighted average of Mn-air ranged from 0.11-0.46 mg/m(3) (55% >0.20 mg/m(3)). MnB >10 microg/l was found in 43% of the workers, but the concentrations of Mn in urine, lead in blood and copper and iron in plasma were normal. Forced expiratory volume at 1s: forced vital capacity ratios (FEV(1)/FVC) were found to be abnormal in 33.3% of the welders after about 1.5 years of welding at the bridge. Mean scores of bradykinesia and Unified Parkinson Disease Rating Scale exceeded 4 and 6, respectively. Computer assisted tremor analysis system hand tremor and body sway tests, and University of Pennsylvania Smell Identification Test showed impairment in 38.5/61.5, 51.4 and 88% of the welders, respectively. Significant inverse dose-effect relationships with CEI and/or MnB were found for IQ (p<or=0.05), executive function (p<or=0.03), sustaining concentration and sequencing (p<or=0.04), verbal learning (p<or=0.01), working (p<or=0.04) and immediate memory (p<or=0.02), even when adjusted for demographics and years of welding before Bay Bridge. Symptoms reported by the welders while working were: tremors (41.9%); numbness (60.5%); excessive fatigue (65.1%); sleep disturbance (79.1%); sexual dysfunction (58.1%); toxic hallucinations (18.6%); depression (53.5%); and anxiety (39.5%). Dose-effect associations between CEI and sexual function (p<0.05), fatigue (p<0.05), depression (p<0.01) and headache (p<0.05) were statistically significant. CONCLUSIONS: Confined space welding was shown to be associated with neurological, neuropsychological and pulmonary adverse health effects. A careful enquiry of occupational histories is recommended for all welders presenting with neurological or pulmonary complaints, and a more stringent prevention strategy should be considered for Mn exposure due to inhalation of welding fume.

Adult↗
PubMed2004

Performing chest compressions in a confined space.

Standard cardiopulmonary resuscitation (CPR) may be difficult to perform in a confined space. This study set out to evaluate alternative techniques of chest compression, which may be easier to perform in such situations. Nineteen airline employees, trained in basic life support (BLS), were recruited to take part in the study. Following refresher training in standard one- and two-person CPR, they were taught two alternative techniques of chest compression: one-person over-the-head (OTH) and two-person straddle (STR). Their performances of chest compression during one-person standard CPR (St-1) and two-person standard CPR (St-2) were then compared with their performances during OTH and STR using a recording manikin. There were no statistically significant differences between the two-person methods of compression (St-2 and STR) for any of the parameters measured. There were no statistically significant differences between the one-person methods of chest compression (St-1 and OTH) for the average compression rate, the number of chest compressions achieved in a minute, or the average hands-off time per cycle. For OTH the average compression depth was significantly less than for St-1 (P = 0.0149) and there were more compressions of incorrect depth (P = 0.0400). The average duty cycle was significantly higher for OTH (P = 0.0045). 30.4% of compressions were incorrectly placed for OTH compared with 7.7% for St-1 (P = 0.0025). It was concluded that the quality of chest compression during two-person straddle CPR compares favorably with chest compression during standard two-person CPR, and may be useful in situations where space is limited. If only one rescuer is available to perform CPR, and limited space makes it impossible to carry out standard CPR, over-the-head CPR is an alternative method. However, in this study, hand placement during chest compression was poor, and additional training may be necessary before it can be considered a safe technique.

Adult↗
PubMedDate not supplied

Injuries after use of the lacrimatory agent chloroacetophenone in a confined space.

When the lacrimatory agent chloroacetophenone was released into 44 prisoner cells, 8 prisoners required hospitalization and 20 more received outpatient physician care for injuries. Contact with water contributed to the injuries caused by chloroacetophenone, but prolonged exposure in a confined space was probably the principal cause of morbidity. In a confined space the lacrimatory agent chloroacetophenone is relatively toxic.

Burns, Chemical↗