Is it safe to stay in a room protected by a LOX fire prevention system?

What applies to work in rooms where the oxygen level is reduced?

LOX is currently used in many large installations where people stay and work as normal. There are potentially many advantages and a lot to save by choosing a LOX system for fire prevention, but some are unsure whether working in rooms with a reduced oxygen level can be harmful to health, and therefore hesitate to consider it when designing fire protection.

For more than a hundred years, research has been carried out on the effects of low-oxygen air on humans. Even though it can be dangerous to stay in “very thin air” for a long time, research shows that there is no basis for generally excluding anyone from working at high altitude, or in rooms where the oxygen conditions correspond to high altitude.

On the contrary: as long as you stay within risk class 1 or 2 (up to 2,700 metres altitude, or 14.8% oxygen), there are no special risks associated with normal work in rooms with reduced oxygen levels.

• Above 17% oxygen is considered completely risk-free for everyone.
• Down to 14.8% oxygen is considered completely risk-free for everyone except people with severe heart and lung diseases.
• There are no special recommendations for children or pregnant women.

Heart and lung disease, discomfort, and levels below 14.8%

People with severe heart or lung disease are not necessarily excluded from staying at high altitude either. It is recommended, however, that their reaction is tested under controlled conditions before any stays at altitude, so that they can be excluded if necessary.

Some people may feel discomfort the first few times they are in a room with a reduced oxygen level, but all research shows that this goes away as soon as they leave the room. The effect is not permanent or harmful.

Levels below 14.8% oxygen and further down can be harmful to health and require more follow-up and knowledge. Concentrations that low are not necessary to prevent fire in the vast majority of materials.

How can you be sure that LOX is a safe solution?

Since September 2017 there has been a European standard for fire protection using reduced oxygen – EN 16750. The Nordic countries are obliged to accept it as their national standard, without changes. That means the standard has applied in the Nordic countries from March 2018 at the latest.

The standard sets minimum requirements and requirements for the design, installation and maintenance of permanent oxygen reduction systems. It applies to systems where nitrogen is used to replace the oxygen in the air (LOX – Low OXygen system).

In addition to the technical requirements, the standard sets out procedures for instructing personnel in connection with stays in LOX rooms, and gives guidelines on the measures required for safety.

For anyone introducing a LOX system, the standard is a useful tool. It gives clear instructions on what is required of the various elements in the solution.

We recommend reading the standard alongside the UIAA (The International Mountaineering and Climbing Federation) recommendation on work in hypoxic conditions, Recommendation No. 15.

Research has also been carried out in Sweden into whether cognitive ability is impaired by working in an environment with about 15% oxygen. The conclusion of that research is that no effect can be seen from such a reduction.

How it works

Normal air consists of about 78% nitrogen and about 21% oxygen. The remainder is argon and other gases in small amounts. It is the amount of oxygen that determines whether fire can start and develop further.

In a LOX system, enough of the oxygen in the air is removed that fire can no longer occur, and the room and its contents are therefore protected against fire.

What is required, and where it fits

It is important that the room to be protected is reasonably airtight, so that the oxygen-reduced air does not simply disappear. Beyond the air production equipment itself, all that is required is simple installation of air pipes and oxygen level sensors. The system works well alongside closed systems for balanced ventilation, for example.

LOX is ideal in:

• Data rooms and data halls
• Cold storage
• Li-ion battery storage
• Archives and museums
• Cellulose storage
• Storage for hazardous substances

Sources and references

The documentation behind the assessments above:

• European standard EN 16750:2017 Fixed firefighting systems – Oxygen reduction systems – Design, installation, planning and maintenance.
• Report no. 2/2013. Undersökning av den kognitiva förmågan vid arbete i syrereducerad miljö vid Forsmarks kärnkraftverk. Åsa Stöllman, Thomas Höljö.
• Recommendation of the UIAA Medical Commission Vol. 15. Work in Hypoxic Conditions – Including work in low oxygen facilities and work at high altitude. Intended for Physicians, Occupational Health and Safety Advisors, Interested Non-medical Persons.