Oxygen Enrichment

Inspired partial pressure of oxygen (PO2) and lack of oxygen

The reduction in oxygen is best described by the fall in inspired partial pressure of oxygen (PO2).

The partial pressure is the pressure than a particular gas exerts independently. This is the pressure that a component of a gaseous mixture would have if it alone occupied the same volume at the same temperature as the mixture.

The partial pressure can be calculated by the following formula: Partial pressure = %gas x atmospheric pressure

Where the atmosphere pressure is PN2 + PO2 + PCO2 +PH2O, in accordance with Dalton's Law (the total pressure of a mixture of gases is the sum of the pressures each component would have if it alone occupied the volume of the mixture at its temperature). The atmosphere pressure varies at different latitudes and altitudes .

It should be taken into account that for low latitudes (ex. Ecuador) the barometric pressure for a given altitude is higher than predicted from the Standard Atmosphere (1atm representative for pressure at sea level at T=20C)

Physiological effects of oxygen deprivation

The most common physiological effects of high sites where there is low oxygen pressure are breathlessness, irritability, headaches, nausea and poor judgment. Other effects caused by a lack of oxygen are impairs in sleep quality, problems in mental performance productivity and general dissatisfaction. For example, one of the most unpleasant features of going to high altitude is difficulties with sleeping.

The rate at which humans can perform physical work (power output) depends on the amount of oxygen available to the body, so it is not surprising that as the altitude increases, maximal oxygen uptake falls and therefore the need for supplementary oxygen is well recommended.
Some statements refer that oxygen enrichment for altitudes of 5000 m and above should be mandatory and would also be helpful at more modest altitudes such as 4200 m.

Problem shooting: Oxygen enrichment chambers

The most effective way of improving human performance in areas with deprivation of oxygen is to add supplementary oxygen. Recent technical advances allow this to be done very efficiently by oxygen enrichment of room air.

Other solution for workers at places where there is lack of oxygen is by portable oxygen units with an oxygen supply of 2Liters/min per person through nasal cannulas that are placed just inside the nostrils.

Please note that this solution is similar to the individual oxygen intake provided by Lenntech oxygen bars which is exclusively intended for recreational use.

It must be stated that oxygen enrichment of room air at high altitude to the levels of 24% does not increase the fire hazard above that for air at sea-level. This is because the partial pressure of O2 is still far below this pressure at sea-level.

Cases of study and technical requirements.

Some experimental research studies have been carried out in order to improve sleep of workers at mines located at high altitudes (specially in Los Andes in South America) by increasing the oxygenation of the dormitory to a 24% oxygen content.

The area of study has a volume of 208m3 where six people will sleep. Oxygen output requirements is 400L/h per person (=6.7L/min/person) which means 40L/min per person. The oxygen generator necessary for this application is Lenntech oxygen generator Quad 100 with compressor that can deliver 47L/min of oxygen at high purity (99%).

The occupants of the room are generally unaware of the increase of oxygen. Nevertheless the experimental research has found that their mental and physical performance is significantly enhanced.

Other study that was carried out is a mobile home trailers of 34m2 with sanitary and kitchen facilities. The oxygen generator necessary in this case is Lenntech WH 23 with 11 L/min O2 outputs.

The principle of the concentrators is that when air is pumped into a tube of synthetic zeolite at high pressure, nitrogen is preferentially adsorbed and the effluent gas has an oxygen concentration of 90-95%.After a short period the zeolite is unable to adsorb more nitrogen and the high pressure air is
switched to a second tube while the first tube is purged of nitrogen using air at normal pressure.

Requirements to maintain oxygen values of 24 to 25%:

- 1. Sealing the area. Sealed all joints with silicone caulking and create a double-door airlock. This is necessary in order to maintain constant environmental conditions in the study room.

- 2. Fresh air drawn in a ventilation duct. The ventilation level of the room is maintained at the minimum acceptable level to reduce the amount of oxygen that has to be generated. For example, according to the ASHRAE (American Society of Heating, Refrigerating, and Air Conditioning Engineers) 1975 standard the requirement for ventilation is 8.5 m3.h-1 per person.

-3. Injection of O2. The oxygen generator is enclosed in a well ventilated area outside the oxygen enriched room.

-4. Carbon dioxide and gases monitoring system. The carbon dioxide concentration in the room is monitored and kept at or below 0.3% (the concentration in air is about 0.03%) as an useful index of the adequacy of ventilation.

- 5. Lighting, electrical outlets

Estimated costs
It is neither difficult nor expensive to set up an oxygen-enriched room. In general, the costs to set up an oxygen enrichment chamber are as described below:
- Oxygen generator with compressor around 1,000 Euros up to 4,000 depending on the oxygen output necessary.
- Sealing area estimated cost of 329Euros
- Two double door entries in the control room which cost 1317 Euros
- Piping is 21Euros

And other costs such as flow meters, lighting and electrical outlets in the room. The only running cost of oxygenating a room is the cost of the electrical power.

Further information
For further information in relation to oxygen bars and oxygen click on the following topics:

- Oxygen bars
- Equipment to install an oxygen bar
- Oxygen generator Lenntech
- Infusor Oxygen-Aromas Lenntech
- Aromas
- Cannulas
- Oxygen
- Oxygen Enrichment
- Generadores de ozono