Oxygen Breathing Apparatus Research Articles

Canaries, camouflets, and carbon monoxide: making ‘Proto Man’ in Britain’s tunnelling war 1915–1918

ABSTRACT Focused mainly on the gas mask, historians of technology have paid little attention to the use of oxygen breathing apparatus in World War I. This article explores how an assemblage of technology, avian life, and experimental physiology resulted in the ‘Proto Man’ – a militarized mine rescuer vital for fighting Britain’s tunnelling war. Wartime mobilization of science pushed the improvement of oxygen equipment and the study of human performance. The success of ‘Proto Man’ was not narrowly limited to technical refinements of equipment or discoveries in physiology. Instead, this article argues for the centrality of the canary as a living gas detector endowing ‘Proto Man’ with more-than-human sensing of carbon monoxide. Easily surpassing chemical testing methods in utility and practicality, the trench canary provided an essential role for the non-human amidst the broad militarization of extreme environments during the twentieth century.

Thermal Load of Mine Rescuer in the Underwear and Protective Clothing with Phase Change Materials in Simulated Utility Conditions.

A new set of underwear and protective clothing with phase change materials (PCM) for mine rescuers has been developed in order to increase their safety of work. It includes PCM pouches absorbing excess heat from the body. In order to evaluate thermal load of mine rescuers, physiological tests were carried out for three variants of possible use of the developed set of clothing: for mine rescuers wearing only the underwear with PCM; for a set of underwear and protective clothing; and for a complete set of clothing with closed-circuit compressed oxygen breathing apparatus. Tests were performed in difficult microclimate conditions, reflecting the typical working conditions of rescuers that cause a significant thermal load. The use of outer clothing shortened safe time of exposure to such conditions by about 36%, while the addition of respiratory protective device to this set further shortened this time to a lesser extent (by another 13%).

Acoustic estimation of the impact of a single dive using a closed-type breathing apparatus on the ventilatory function of the human lungs

Diving negatively affects the human respiratory system, especially if an oxygen breathing apparatus is used. The spirometry indices generally used to estimate the ventilatory function of the lung have a poor sensitivity to the toxic effect of hyperbaric hyperoxia. The goal of this study was to estimate the possibilities of using the forced expiratory (FE) tracheal noise duration. The study was done on 48 divers who had been tested before and after a single dive.

Thermal status of wet-suited divers using closed circuit O2 apparatus in sea water of 17-18.5 degrees C.

A wet suit may not provide adequate thermal protection when diving in moderately cold water (17-18 degrees C), and any resultant mild hypothermia may impair performance during prolonged diving. We studied heat exchange during a dive to a depth of 5 m in sea water (17-18.5 degrees C) in divers wearing a full wet suit and using closed-circuit oxygen breathing apparatus. Eight fin swimmers dived for 3.1 h and six underwater scooter (UWS) divers propelled themselves through the water for 3.7 h. The measurements taken throughout the dive were the oxygen pressure in the cylinder and skin and rectal temperatures (Tre). Each subject also completed a cold score questionnaire. The Tre decreased continuously in all subjects. Oxygen consumption in the fin divers (1.40 l.min-1) was higher than that of the UWS divers (1.05 l.min-1). The mean total insulation was 0.087 degree C.m2.W-1 in both groups. Mean body insulation was 37% of the total insulation (suit insulation was 63%). The reduction in Tre over the 1st hour was related to subcutaneous fat thickness. There was a correlation between cold score and Tre at the end of 1 h, but not after that. A full wet suit does not appear to provide adequate thermal protection when diving in moderately cold water.

AGGRESSIVE WATER FOG ATTACK REDUCES HEAT STRAIN DURING SHIPBOARD FIREFIGHTING1182

This study compared the use of two shipboard firefighting water attack methods, direct straight-stream (DIR) and aggressive fog (FOG), on heat strain of naval firefighting personnel. Eight males and four females aged 31 ± 4 yrs served as subjects. Portable data logger recordings were made of heart rate (HR), and rectal (Tre), chest (Tch), arm (Tar), hand(Tha), index finger (Tfi), thigh (Tth), foot(Tfo), and big toe (Tto) temperatures during altematingly ordered DIR and FOG tests. Subjects wore cotton work clothes underneath the standard Navy firefighting ensemble plus oxygen breathing apparatus. Fire compartment temperatures at the time of entry averaged (±SD) 591± 43°C. Firefighters entered into the fire compartment 1.2 to 1.8 m, took a crouched position, and set the nozzle angle to either 60° for FOG or 30° for DIR. During both FOG and DIR, water was discharged in a series of 2 or 3 short bursts lasting 2-3 sec in duration. During pre-activities and actual firefighting, HR and all body temperatures increased progressively. Time to extinction of flames was significantly (p<.05) less for FOG (9.1 ± 0.6 min) compared to DIR (10.9 ± 0.6 min). Analysis of covariance (adjusted for pre-entry values) showed no differences for Tha ([horizontal bar over]X=38.2°C), Tfi ([horizontal bar over]X=41.6°C), and Tth ([horizontal bar over]Xs=38.2°C). However, FOG Tre ([horizontal bar over]X=38.2°C), Tch([horizontal bar over]X=39.6°C), Tar ([horizontal bar over]X=40.0°C) and Tfo ([horizontal bar over]X=36.0°C) were lower (p<.05) compared to DIR (38.5°C, 40.4°C, 41.0°C, 37.4°C, respectively). HR for FOG ([horizontal bar over]X=185 bpm) was also lower (p<.05) than DIR ([horizontal bar over]X=171 bpm). Our findings suggest that use of the FOG attack method reduces heat strain in personnel conducting shipboard firefighting.

The development of a liquid oxygen breathing apparatus working at positive pressure∗

Bentley, R.A. and Roff, M.W., 1984. The development of a liquid oxygen breathing apparatus working at positive pressure. Journal of Occupational Accidents, 5: 233–242. The protection which any breathing apparatus affords is limited by the effectiveness of the seal between the apparatus and the wearer. All face-masks may leak to some degree, the maximum inward leakage permitted by the British Standard Specification is 0.05 per cent of the wearer's minute volume under conditions of negative demand. This figure is a compromise between the considerations of the toxicity and likely concentrations of gases in irrespirable atmospheres and the time for which such apparatus would normally be used. Extra protection can be achieved if the pressure in the face-mask is maintained at a positive level throughout the breathing cycle, so that any leakage is outward. Compressed air breathing apparatus operating on this principle are commercially available and are widely used in industrial situations. The breathing apparatus used in the mining industry in the U.K. operate on a closed circuit principle and this paper describes a method used to convert such an apparatus to operate at positive pressure. A laboratory prototype apparatus and an experimental face-mask have been constructed. An important feature of this system is the maintenance of the seal between the inner and outer mask, consequently some form of independent inner mask adjustment is necessary. A series of tests at various work rates with the apparatus connected to a breathing simulator has shown that positive pressure can be maintained in the mask outer cavity. A range of leakages at the inner mask sealing edge have been simulated to accommodate the likely levels of fit which may be achieved in practice. Limited wearer trials have shown that the apparatus is comfortable to wear and the normal functioning of the equipment is not impaired.

Oxygen Breathing Apparatus at High Atmospheric Pressure

Oxygen Breathing Apparatus at High Atmospheric Pressure

A Study on the Oxygen-breathing Apparatus

A Study on the Oxygen-breathing Apparatus

The use of oxygen apparatus by acclimatized men.

Although oxygen breathing apparatus has a wide range of applications it is only in Himalayan mountaineering that the users are likely to be fully acclimatized to high altitude. Above 25000 ft. even acclimatized men are severely handicapped without additional oxygen and hence we have little accurate information on phenomena occurring at these heights. The following notes describe observations made during the British Expedition to Cho Oyu of 1952 and the Everest Expedition of 1953, when oxygen apparatus was used to a greater extent than in previous mountaineering. The conditions met in mountaineering at great altitudes are not easy, and a breathing set must meet several stringent requirements. Thus the greatest weight which a climber can carry over difficult ground for many hours is about 60 lb., but a load as great as this is a severe handicap and weight and bulk should both be small.

Oxygen and Everest

ON the interesting subject of the need for oxygen on Mount Everest, Prof J. Barcroft has made the remark, before Section I of the British Association, that the whole matter is now merely “an engineer's problem”: the problem of designing a light and efficient oxygen breathing apparatus. This point of view is ably supported by Prof. Margaria.1 There is, however, something more: namely, the disadvantage of acclimatisation in a man using such apparatus. If it is one of the ‘open circuit’ type, acclimatised breathing causes a huge waste of oxygen and adds correspondingly to the difficulty of transportation. Yet a man dare not relinquish this physiological condition, even if he could. For if he relinquished it, he would die of asphyxia as soon as he took the apparatus off.

Group-Capt. Martin Flack, C.B.E

To Martin Flack, whose death at the age of forty-nine years occurred on Aug. 16, we are indebted for the clear setting out during the War of those principles which made high flying possible by the use of oxygen breathing apparatus, and for the tests which differentiated suitable from unsuitable candidates for flying. Moreover, he did excellent work in recommending the physical training required to make and keep those chosen for the air service in fit condition. In addition, at the time when cerebro-spinal fever caused great anxiety, he did first-class work in elucidating the means, by ventilation, spacing out beds, etc., of keeping down infection and for carrying out serum treatment.

Comparison of gas masks, hose masks, and oxygen-breathing apparatus

Report providing information about the most appropriate kinds of breathing apparatus -- gas masks, hose masks, or self-contained oxygen-breathing apparatus -- to use in different situations.

Permeation of oxygen breathing apparatus by gases and vapors

Permeation of oxygen breathing apparatus by gases and vapors