After the Cho Oyu expedition the Everest committee appointed as oxygen controller Peter Lloyd, who had used oxygen on Everest in 1938 (and as oxygen officer for the 1953 expedition, Tom Bourdillon).
At the committee’s request, a group of experts was brought together by the M.R.C., under the chairmanship of Sir Brian Matthews, to consider the amount of oxygen needed and the most suitable kind of apparatus to use. Two types of equipment were considered, one based on the open-circuit and the other on the closed-circuit principle.
Open-circuit apparatus has been fairly well tested on Everest; it is simple and reliable to operate. Closed-circuit apparatus is much more complicated and has many practical snags.
While closed-circuit sets have been in use for many years for mine rescue and fire fighting, no existing set could handle the volume of respiration of men climbing at altitude, nor are they built to supply oxygen over long periods.
It was clear then that entirely new sets would have to be developed for Everest and it was doubtful if they could be made reliable enough in the time available. This being so, it was decided to concentrate mainly on the well-tried open-circuit principle and take some closed-circuit sets for trial.
From an article by Dr Griffith Pugh in the Himalayan Journal (18) published in 1954
- Everest 1953 The expedition took the following Oxygen equipment: Sixty light alloy and a hundred RAF cylinders containing in all nearly 200,000 litres of oxygen This compared with 28,000 litres taken in 1922, and 30,000 litres taken by the Swiss in their expedition to Everest in 1952. The open-circuit sets weighed about 30lb, with two cylinders of oxygen each holding 800 litres. This would give a man a 6 hour supply at 4 litres per minute.
- The closed-circuit sets weighed 35lb, with one oxygen cylinder and a 10lb soda-lime cannister. On arriving at base camp the expedition found that 18 cylinders had leaked leaving about 150,000 litres of oxygen, most of which was used. About one-third of the oxygen was used for training and a small amount for experimental purposes.
- The first assault was done with closed-circuit sets. Bourdillon and Evans climbed from the South Col (25,000 feet) to the South Summit at 28,700 feet and back in a day. On the first part of the route, they climbed at the rate of 900 feet an hour.
- The second assault was done with open-circuit sets, Hillary and Tenzing going from the top camp at nearly 28,000 feet to the top and back to the col. On the first part of the route they climbed at 400 feet an hour, but this should not be compared with the closed-circuit performance, as they were using steps cut by the support party.