WG Fire Exclusion System

The WG Fire Exclusion System (WG FES) provides a permanent means of inhibiting a fire starting and prevents the expensive after effects of building damage, the loss of building use and the potential of loss of life.

WG FES is a revolutionary fire prevention technology, with the unique ability to create a breathable oxygen-reduced (hypoxic) environment which prevents flame ignition and at the same time continues to provide a safe and healthy environment for human occupancy.

The WG FES differs from conventional fire extinguishing systems in that it provides a continuous level of prevention rather than a one off discharge of extinguishing agent when a fire has been detected.

WG FES - Briefly how it works

• Ambient air is drawn into a hypoxic generator where it is purified and turned hypoxic (oxygen reduced);
• The hypoxic air ventilates the entire room, inhibiting any common fire ignition;
  A control unit monitoring the room with oxygen sensors permanently ensures a stable hypoxic environment in the room.

Unmatched Fire Safety - WG FES prevents fire proactively instead of suppressing it after it has started and damage has already occurred.

Absolute Safety for Human beings - WG FES produces and uses breathable air for fire prevention, thus avoiding any hazard to human occupants and any damage to the protected areas and their content.

Environmental friendliness - WG FES uses natural, ambient air as its resource - no chemicals, no gases or similar are involved. The WG FES agent is simply hypoxic (oxygen-reduced) air, nothing is added.

Fire Triangle

Before a fire can actually occur, three things must be present in the correct proportions: an ignition or heat source, a fuel source (materials that burn) and an oxidizer (gases that increase oxygen concentration and support combustion).

These three elements are known as the fire triangle, when the three components converge in the proper proportions a fire can quickly ignite.

If the oxygen component (or other components) is not present in its correct proportion a fire will not be able to ignite.

Normal Atmosphere

In normal circumstances air is a mixture of oxygen and nitrogen, together with small quantities of argon, carbon dioxide and other gases.

Oxygen is the critical element that supports both life and combustion, when the oxygen content is intentionally lowered for special applications the resulting gas is called hypoxic air or reduced-oxygen air.

Reduced Oxygen Atmosphere

The WG FES reduces the oxygen content in the designated protected areas to approximately 15% making it impossible for a fire to be able to ignite.

The WG FES can be applied to installations where it is possible to control the environment of the protected spaces, either exclusively for fire prevention or in combination with other indoor climate control (e.g. temperature, humidity).
The system can typically be used in:-

Applications

• Ammunition Storage Areas;
• Art Galleries;
• Banks;
• Cold Storage Areas;
• Computer Facilities;
• Document Archives;
• Libraries;
• Security Control & Command rooms;
• Telecommunication Equipment rooms;
• Underground Car Parks;
• Vaults;
• Warehouses.

WG FES when used in protected areas that contain artefacts and other materials affected by oxidation (e.g. food, paper, paintings and metals) will also reduce oxidative degradation.

Conventional Systems - Disadvantages

• Serious damage can occur before a fire is extinguished;
• The fire damaged area will require cleaning and refurbishment before return to normal business operations can take place;
• You never know if a Gas Extinguishing system is going to actually work in the event of a fire, you cannot test it;
• Gas Extinguishing systems, are a one activation system, once discharged they provide no protection until the gas bottles are replaced;
• Gas Extinguishing bottles take up a lot of space;
• Gas Extinguishing systems are very expensive and disruptive to install;
• Gas Extinguishing systems require means of pressure relief to be installed in the protected area.

The WG FES overcomes all of the above and many other disadvantages associated with conventional fire extinguishing systems.

Protected Area - Air Tightness

The designated WG FES protected area will need to be sealed to prevent ingress of normal atmosphic air, to enable retention of the hypoxic environment.

The area will be required to have a minimum N50 value of less than 1.0 to meet the maximum allowable infiltration of external non‑hypoxic air, this can normally be achieved by using various building sealing techniques. If an air conditioning system is present, it must be of the re-circulatory type. It is not possible to open windows in the protected areas.

WG FES System Size

Westminster can offer a large variety of hypoxic air venting systems that can fit virtually any application; they range from self contained units for smaller volumes to larger systems for multi floored buildings.

WG FES systems can protect single or multiple rooms and compartments with volumes of up to several 100,000 m3/mil. cuft and even more.

System Components

The oxygen reduction in the designated protected area is achieved by the installation of a WG Fire Exclusion System, this consists of:-

• Control Panel & Hypoxic Air Generator;
• Oxygen Sensors;
• Pipe Work, to extract and input air.

Control Panel & Hypoxic Air Generator example:

Hypoxic Air Generator Unit

The Hypoxic units are equipped with highly reliable compressors, refrigerant dryers, separate condensate cleaners and buffer vessels;
Each hypoxic air generator unit has a 3-stage pre-filtering and a moisture alarm.
3-phase 400v and 50Hz power supply (other voltages on request);
The layout and base size of the system may be adjusted to specific requirements and size of the particular location.
All systems can be configured as Twin-Systems, offering full redundancy of compression and generator units to improve failure safety.

Oxygen Sensors

The installation design of a WG FES will incorporate a minimum of two oxygen independent sensors in different locations in each protected area. The sensor outputs are sent to monitoring and control points (e.g. the fire alarm panel and the building management system), as required.

The location of the oxygen sensors is such as to not be influenced by the injection of hypoxic air or nitrogen. The readings from the oxygen sensors reflect the homogeneity of the hypoxic air environment.

Control Panel

The WG FES is equipped with a touch panel control unit, which can be located remotely and is able to communicate with Building Management Systems. As well as monitoring and controlling the hypoxic generators the Control panel provides performance indicators for each protected space.

• An intergal battery assures the function of the control and alarm system even in the case of general power failure;
• Oxygen concentration level as indicated by every oxygen sensor;
• High and low oxygen alarm conditions;
• An output indicating the operation of any other system alarms (e.g. oxygen sensor fault);
• The monitoring system complies with BS EN 61508.

Hazard and Risk Assessment

Design and installation of hypoxic air fire prevention systems should follow a suitably detailed hazard and risk assessment, including consideration of the suitability of such a system for the specific application at its location and any protective measures required for the health and safety of all persons having access to the protected space.

Safe Working Conditions

• It is proven, that reducing the partial pressure of oxygen to a certain extent does not have any negative effects on the health of human life;
• People live permanently in altitudes of 4,000 m / 13,000 ft and above;
• Persons travelling on modern airplanes will have experienced oxygen concentrations of around 15%;
• Scientific studies confirm that working under defined hypoxic conditions is safe for human life.
• We recommend that after 6 hours persons working continuously in a protected area take a 20 minute break in a normal atmosphere;
• The United Kingdom HSE has deemed that an area with reduced oxygen content would be classed as a confined working space. This requires that there should be a safe system of work and effective management procedure in place that monitors the movement of people through the area.

Where WG FES Cannot be installed:-

• Hypoxic air fire prevention systems should not be used in conjunction with smoke control systems;
• A hypoxic environment cannot prevent non‑oxidizing smouldering or pyrolysis;
• Hypoxic air fire prevention systems may not offer full protection in the following areas:

a) Where explosive gases (or explosive mixtures of gases), particulates and liquids are present, or where there is the possibility of explosive atmospheres being created within the range of system operating oxygen concentration levels;

b) Where reactive metals, gunpowder, metal hydrides, hydrazine and other chemicals capable of auto thermal decomposition are handled or stored;

c) Where chemicals containing oxygen available for combustion (e.g. cellulose nitrate) are present.

Normal Fire Detection System

A normal Fire Detection system must be installed in the WG FES protected area.

Event of Power Failure

In the advent of a power failure the control panel has integral battery backup; the continued room protection will depend on the leakage rate in the protected area.