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Fire Protection – Oxygen Reduction Systems


Wagner Group GmbH introduced the technology of using an oxygen-reduced atmosphere for the purposes of fire prevention around 20 years ago under the trademark of OxyReduct®.

The concept behind the OxyReduct product is quite simple: the use of nitrogen gas to reduce the oxygen concentration in the protected area to the point where fires can no longer break out or develop. Key to the development of the OxyReduct system has been the advancement by Wagner of the process of on-site nitrogen generation from the ambient air, removing the need for space consuming and expensive storage of nitrogen in cylinders. 

Recent years has seen traction in the international sales and installation of OxyReduct systems for the protection of specific risk environments owing to the benefits of fire prevention against damage limitation. Another advantage of the system is its ability to be retrofitted into an existing building. It can be installed with minimal disruption compared with other fire-protection systems. However, the building's fabric needs to be scrutinised for suitability, as the cost of air sealing can be high when added to the cost of the system.

It is reported that around 500 OxyReduct systems have been installed worldwide which have proved to be a cost-effective solution, compared with traditional protection systems for high-value storage and business critical applications. However, take up in the UK has been fairly small with some 20 installations to date.   Typical environments for OxyReduct include:

  • Data centres

  • Cold stores

  • Automated high-bay warehouses

  • Hazardous materials storage

  • Libraries and museums.

  • Notable OxyReduct installations in the UK include:

  • Essex Fire and Rescue Service new command and control centre, Witham

  • The British Library document storage centre, Boston Spa

  • AstraZeneca PLC pharmaceuticals warehouse, Macclesfield

  • The new Birmingham Library.

Whist the OxyReduct product is unique in the UK, it is understood that similar systems based on oxygen reduction are available in other parts of Europe.

 OxyReduct Design

In general terms the OxyReduct system consists of the following main components:

  • An OxyReduct generator (see above), normally contained in a separate plant room in which nitrogen is extracted from the ambient air.

  • Control equipment in which the entire process is managed, linked to controllers in which the oxygen content is constantly monitored and adjusted to within the defined protection levels.

  • Distribution pipework

  • Multiple oxygen sensors throughout the projected premises via which pre-defined oxygen concentration levels are continually monitored.

  • External indication equipment displaying oxygen concentration levels within any protected area.

Wagner has developed special protection concepts for variety of applications which are based on a risk analysis and the client’s specific needs. These are summarised as follows:

Concept 1 - Permanent reduction of oxygen concentration levels. By continuously reducing the oxygen concentration levels, the OxyReduct system prevents fire from developing or spreading. To achieve this, oxygen levels are defined based on the ignition thresholds of the materials present (typically 15 vol.%) and the atmospheric oxygen reduced and maintained to this target concentration level, creating a protective atmosphere. (Natural atmosphere has an oxygen content of 20.95 vol.%.)

Concept 2 – Oxygen reduction with two adjustable levels.  OxyReduct can also adjust oxygen levels completely automatically at specific times. For example, the protected area might have a slightly reduced O² concentration of 17 vol.% during the day, ensuring that it remains freely accessible, whereas during night and weekend hours, the system automatically reduces oxygen concentration to a second level (14.6 vol.%) in order to ensure maximum fire protection during periods on non-supervision.

Concept 3 – Quick release. The OxyReduct system lowers the atmospheric oxygen concentration to 17 vol.%, thus significantly limiting fire behaviour, also working in tandem with a smoke aspirating detection system which on activation rapidly lowers oxygen concertation levels to a point where the fire is extinguished and lower concentrations maintained to prevent re-ignition.

Concept 4 – Two-stage quick action reduction. On activation of a smoke aspirating detection system, the oxygen level is first lowered to 17 vol.%, resulting in a significantly reduced fire behaviour and, in most cases, extinguishment. This oxygen level can be maintained for as long as is necessary for operatives to safely locate and remove the cause of the fire. If during this phase an expansion of the fire should nevertheless be detected, the oxygen concentration is reduced further to a level below the ignition threshold of the predominant materials and fire spread prevented.

Irrespective of whether it is required for the operation of the OxyReduct system (as in the case of concepts 3&4), Wagner’s TITANUS® LPCB approved smoke aspirating detection equipment will invariably be installed in all cases, as part of an overall scheme of protection.


Standards and Approvals

Without exception, all OxyReduct systems are installed in accordance with BSEN 16750: Fixed firefighting systems – Oxygen Reduction Systems – Design, Installation, Planning and Maintenance.

OxyReduct has achieved VdS (German regulatory body) approval. At time of writing (February 2023) the LPCB has yet to develop an approvals scheme for oxygen reduction systems.


 System Monitoring, Inspection and Maintenance

Monitoring of the system on site is accomplished visually and by linkage into the premises building management system (BMS).  It is understood that systems can also be monitored remotely at Wagner’s UK headquarters from where adjustments to operational parameters can be accomplished.

The requirements of BSEN 16750 are that systems are inspected and maintained twice yearly, although Wagner would normally recommend that this is carried out quarterly.

In accordance with the OxyReduct operating manual, user checks should include:


  • The generator for abnormal noise development and any leakage;

  • The system control panel for any pending alarms or faults;

Every 14 days

  • All pressure bearing parts for tightness and integrity (pipes, hoses, connections etc.);

  • Uninterrupted air intake and exhaust;

  • Accessible nitrogen/oxygen pipe lines for damage.


Health and Safety

Whilst the merits of OxyReduct in fire prevention terms are abundant, these need to be considered alongside the risks of health and safety which require close attention.

On account of the fact that oxygen reduction systems require an airtight enclosure in which a reduced oxygen atmosphere is created, these spaces meet the definition of a ‘confined space’ and are the subject of the Confined Spaces Regulations 1997. As result a suitable and sufficient risk assessment should be undertaken for all work activities undertaken from which the appropriate protective measures should be taken. In addition to the in-built oxygen concentration alarms and other safety devices of the system, measures may include:

  • Consideration of any pre-existing medical conditions employees may have and the impact working in reduced oxygen may have on those conditions

  • Health monitoring of staff who will enter the confined space as part of their role.

  • Establish a system for identifying changes in health that may affect the employee’s ability to work in the confined space.

  • Training in alarm recognition, evacuation processes and recognising the symptoms that oxygen deprivation may cause.

  • Assessment the risks to employees from other issues such as the amount of exertion involved in the job which would increase respiration to provide more oxygen, temperature etc.

Of vital importance is the need to ensure that all operating and safety instructions supplied by Wagner, together with those developed locally are fully observed at all times and staff suitably trained.   


Survey Expectations

Whilst OxyReduct is viewed as a highly meritable product with a promising future in the highly protected risks arena, its application as far as the UK is concerned has to date been limited to special/high risk environments such those previously mentioned and is not seen at this stage as a replacement for conventional sprinkler protection and other suppression systems for common occupancies.

In the event that an OxyReduct system is encountered in the field, design details of the system should be ascertained, combined with health and safety protocols applying and the case referred to David Reynolds, Head of Risk Engineering & Surveys.

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