Westminster's total fire prevention concepts can combine advanced fire detection technology together with gaseous fire extinguishing systems.
They have been developed to protect people, critical operations, buildings and importantly the environment.
The Westminster Nitrogen inert gas fire extinguishing system is an essential component of an overall fire prevention concept.
Nitrogen is both an efficient extinguishing agent and environmentally friendly. Suitable for many applications Nitrogen is Westminster's solution to the issues facing critical operation managers - especially those looking for Halon alternatives.
Halon Removal and Replacement
The 1970s saw the introduction of Halon gases - efficient extinguishing agents that posed no danger to people.
During the early 1980s scientific evidence found that the Earths stratospheric ozone layer was being eroded, mainly by man-made chemical substances released into the atmosphere.
Typically CFC's were amongst the worst ozone depleting substances so measures were introduced to control CFC's including Halon gases.
The Montreal protocol introduced measures that saw the halt of virgin Halon gas manufacture at the end 1993.
For a short period of time recycling was used as a means of controlling and reducing the amount of halons in existence. Led by Germany, many mainland European countries adopted removal and destruction policies and made the transition from halons to non-ozone depleting replacements without the need for European enforced legislation.
The UK policy required the removal and disposal of existing Halon fire extinguishing systems by the end of 2003, the policy also includes that Halon fire extinguishing systems must not be refilled after 2002.
Users are now confronted with either the challenge of removal and replacement of fire extinguishing systems that use halons and the development of new fire protection concepts.
Criteria for a Halon replacement were that it had to be:
- Environmentally friendly;
- Easily available;
- Effective against the majority of fires;
- Safe for people;
- Equally important was that the gas must not breakdown into harmful or corrosive by-products when in contact with fire.
These criteria could not be achieved with halocarbon agents or inert gas mixtures containing carbon dioxide.
Nitrogen inert gas fire extinguishing system is the natural choice.
Where to use an Inert Extinguishing System
Any operation that depends on its continuity for success needs adequate fire prevention management, this includes:
- EDP Areas;
- Telecommunications;
- Internet Co-location sites & Farms;
- Logistics Control Areas;
- Production Machinery;
- Archive & valuable equipment stores.
In many of these applications the equipment loss from a fire is a relatively low cost.
It is the cost of business interruption that is critical and for some organisations the difference between success and failure.
How Nitrogen Works
Combustion takes place when fuel, oxygen and heat are present in sufficient quantities.
For a fire extinguishing system to be effective one of these elements needs to be removed, Westminster's nitrogen fire extinguishing system reduces the oxygen concentration within the hazard from the normal 21% in air to below 15% - effectively and rapidly extinguishing fire without endangering personnel.
Nitrogen has almost the same density as natural air, providing retention times in excess of the required 10 minutes and maintaining the extinguishing mechanism.
On discharge nitrogen mixes with the air at a molecular level combining with air to produce an evenly reduced oxygen environment throughout the enclosure height.
Westminster's Nitrogen inert gas fire extinguishing systems are designed to control and extinguish class A, B and C material fires.
Nitrogen Systems
The use of nitrogen in fire extinguishing systems is not a new concept; it has been used as a propellant in halocarbon systems for many years.
Nitrogen is colourless, odourless and electrically non-conductive.
Fogging or misting on discharge does not occur; exit routes remain visible at all times.
Nitrogen does not generate condensation, which could otherwise combine with combusted products and damage sensitive electronic equipment through corrosion or thermal shock.
Nitrogen displays excellent extinguishing characteristics and offers the user the following advantages:
- Zero ozone depleting potential and global warming potential;
- Safe for people;
- Compact storage space;
- Does not break down in contact with high temperatures;
- Does not fog or impair vision on discharge;
- Provides increased retention times to keep a fire extinguished;
- Is readily available in the event of a discharge;
- Is capable of protecting more than one hazard from the same cylinder bank using directional valves;
- The Nitrogen gas is stored in cylinders at 200 bar, allowing the cylinder bank to be stored remotely from the risk;
- The high pressure allows the customer with much greater flexibility in the choice of cylinder location.
Safe for People
Nitrogen naturally occurs within the atmosphere - the air we breathe contains approximately 78% nitrogen.
A normal air environment in which the Nitrogen level is increased poses no threat to personal safety as the human body is naturally conditioned to breath high levels of nitrogen.
In environments associated with inert gas fire extinguishing systems the low oxygen content automatically leads to accelerated breathing and an increased oxygen intake. Nitrogen is non-toxic in any concentration (unlike halocarbon agents) and provided that the minimum oxygen level limits are applied there is limited effect on people.
Nitrogen inert gas systems can be used automatically in normally occupied areas.
Limit restrictions do not apply to nitrogen although national bodies such as ISO have established minimum oxygen level limits.
System Technology
An important factor for any fire extinguishing system is that the best combination of component technology is used.
Westminster's Nitrogen inert gas systems comprise one or more cylinders connected via a common manifold.
Automatic or manual system operation is available.
Valve design, the size and storage pressure of the cylinders used together with approved computer calculations ensures that the system will operate effectively to extinguish fire.
To provide the best and most cost effective engineered solution Nitrogen inert gas extinguishing systems use a range of re-useable cylinder sizes.
The 140 litre cylinder ensures that the cylinder bank footprint is reduced in comparison with other inert gas systems. Cylinders are colour coded to European standards providing a quick visual indication of the stored gas.
The cylinder discharge valves are operated by solenoid, pneumatic or a combination of both actuators.
When the cylinder discharge valves are opened nitrogen gas travels through the valve and discharge hose into the manifold, the manifold provides a single outlet and delivers the gas into the piping network.
To ensure the correct amount of nitrogen is discharged into the risk the piping network is designed and sized and the discharge nozzles drilled such that the nitrogen gas accurately discharges through the piping network.
Systems may be configured to suit any application; they can be installed as a dedicated system protecting one hazard only.
To provide a very cost effective solution a single bank of cylinders may be shared between a number of risks using directional valves.
Directional valves are used to control the flow of gas in systems that are protecting more than one hazard from a common bank of cylinders.
They are installed in the piping network after the manifold and are normally closed.