Summary
Breathing resistance is usually defined by work of breathing per volume respiratory ventilation. It is divided into internal and external resistance and also into an elastic and a resistive component. Total breathing resistance is an important factor, limiting a diver’s physical capacity. In unmanned tests of breathing equipment, only external breathing resistance is measured. The ultimate and ideal requirement for breathing resistance is that the equipment adds no extra resistance to breathing, but instead assists respiratory ventilation so that the density dependent increase of internal resistance is reduced. Realistic requirements, however, must be set so that total cost to fulfil them is justified by gain in safety and efficiency. To determine this, breathing resistance must be weighted against other important properties of the life support equipment such as complexity, fail frequency, maintenance, mobility, entanglement, noise, vision, temperature, pCO2, pO2 and humidity. Requirements for breathing resistance are included in different proposed performance goals for breathing equipment. At a workshop held at NUTEC in 1981, Morrison’s performance goals proposed for Department of Energy gained most support. NEDU also presented performance goals which were about equal on the important points. Main differences were: NEDU proposed only recommended, not also acceptance levels like Morrison, NEDU was more stringent for low respiratory ventilations and less stringent for high ventilations, hydrostatic imbalance (HI) was treated differently. The main problem is to interpret ‘recommended’ and ‘acceptable’ levels for breathing resistance. There should be no justification to use equipment not within the acceptance limits. Justifications to use equipment within acceptance levels, but not within recommended levels are: it is impossible to reach recommended levels and at the same time fulfil other requirements, important for safety and efficiency, the depth is shallow and working conditions are specially safe and easy. Today, with improved equipment and much deeper depths, ‘realistic’ requirements have come much closer to ‘recommended’ levels than they were in 1981.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
J. B. Morrison, ‘Physiological acceptance criteria for underwater breathing apparatus’ and ‘Unmanned test procedures for underwater breathing apparatus’ prepared for Petroleum Production Division, Department of Energy, 1981.
B. H. Hjertager and T. Nome, ‘Conclusions from the chairmen’. Workshop on diver’s breathing equipment, Bergen 30 Nov. to 1 Dec. 1981.
D. H. Robertson, ‘Guidance notes on underwater breathing apparatus’. Offshore Research Focus No. 45, Oct. 1984.
J. R. Middleton and E. D. Thalman, ‘Standardized NEDU unmanned UBA test procedures and performance goals’. NEDU Reprt No. 3–81.
I. Rønnestad, ‘Humidified breathing gas’. Thesis, NUTEC, 1984.
J. B. Morrison and S. D. Reimers, ‘Design principles of underwater breathing apparatus’. In The physiology and medicine of diving, (Ed P. B. Bennet and D. H. Elliot ), 1982.
B. Schenk, D. Furevik, K. Segadal and R. E. Peterson, ‘Final report on Deep Mask 81 Program’. NUTEC Report No. 10b-82.
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 1985 Society for Underwater Technology
About this paper
Cite this paper
Segadal, K., Furevik, D.M., Myrseth, E. (1985). Breathing Resistance: Keeping the Requirements Realistic. In: Developments in Diving Technology. Advances in Underwater Technology, Ocean Science and Offshore Engineering, vol 1. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-4970-6_8
Download citation
DOI: https://doi.org/10.1007/978-94-009-4970-6_8
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-8700-1
Online ISBN: 978-94-009-4970-6
eBook Packages: Springer Book Archive