Clean Agent Fire Suppression System
Gaseous fire suppression, also called clean agent fire suppression, is a term to describe the use of inert gases and chemical agents to extinguish a fire. Hegel provide design and installation of Clean Agent Fire Suppression System such as :
Novec 1230 System
Water Mist System
Carbon Dioxide Gas System
Gaseous clean agent systems, typically used to protect electronics, can be used to protect a wide variety of hazards. Some of these mission-critical hazards include:
Military and government facilities where the loss of equipment and a long downtime can lead to lapses in defence systems
Control centres for national air space
Airline flight-control servers
Consumer-product credit card transaction computers
Satellite communication systems
Research and development computing data hubs
Engine test cells with accompanying data.
Types of clean agents
NFPA 2001 provides two main categories of gaseous clean agent systems. Inert gases, such as IG-541, extinguish fires by depleting oxygen, and halo-carbon-based agents, such as HFC 227ea, extinguish fires on a molecular level in the presence of heat, fuel, and oxygen. Note that halo-carbons disrupt the chemical reaction in the fire tetrahedron. Both types of systems have their pros and cons when protecting mission-critical applications. When comparing systems, it is important to consider the cost to refill, shelf life, and environmental concerns.
The weight and required storage area of the suppression agent cylinders are typically smaller with halo-carbon-based systems as compared with inert gas systems. Increased weight can have structural implications that should be accounted for during design. More inert gas cylinders will typically be required than when using halo-carbon cylinders for protection of the same volume. This can be a driving factor on, for example, lease space and building-use planning. It is also an important consideration in retrofit applications in existing buildings, where large areas for cylinder storage are often difficult to find.
Cylinder pressures for halo-carbon-based clean agents are typically lower than for inert gas agents. While the agent pressure drops drastically during release, there are still piping implications to be considered. Some inert gas systems require higher pressure-rated piping and fittings. The increase of room pressure is also greater with inert gases. Pressure relief venting of the protected enclosure is more common with inert gas systems than with halo-carbon systems.
While inert gases reduce oxygen to a level that humans can survive and fire cannot the halo-carbon-based agents extinguish fires while heat, fuel, and oxygen are present. NFPA 2001 and other standards require that the gaseous clean agent is maintained at a minimum concentration threshold within a room for the duration of protection; this is usually referred to as the “hold time.” The latest requirement is 10 minutes.
The hold time is intended to allow the gaseous clean agent to extinguish the fire and reduce the potential for re-ignition due to the presence of heat, fuel, and oxygen. To ensure that the required hold time is achieved, the room must be sealed as much as possible to reduce areas from which gaseous clean agents can leak. Sealing of the room is referred to as room integrity. Typically, walls in the protected area are continuous to the roof or floor/ceiling assembly above, or to a “hard” gypsum ceiling. Dampers or HVAC equipment controlled by the fire alarm system may be necessary to maintain room integrity. Caulking to address holes and other leakage paths in walls is usually necessary. Finally, seals around doors equipped with automatic closer may be needed to minimize leakage.
During construction, room integrity is measured by administering what is commonly referred to as a “door fan test.” This test uses specialized equipment to pressurize the enclosure and measure leakage rates, which then can be translated into hold times.
Early detection is imperative for all types of clean agents. The systems are most effective when fires are in the incipient stage. Using heat-sensing detectors for system activation are not industry standard due to the delayed detection and the resulting larger fire size. This is especially important with halo-carbon-based agents where agent thermal decomposition can occur, resulting in hazardous agent byproducts. As a result, smoke-sensing detectors that identify products of combustion in the incipient stage are typically used in clean agent systems.
Perhaps the most important consideration when choosing a control panel is the listing of the control panel. The listing must include fire suppression agent releasing and must be cross-listed with the solenoid used to release the gaseous clean agent into the piping network. This is an NFPA 2001 requirement to ensure the control panel and gaseous clean agent system communicate seamlessly.
Many systems in fire protection interact with one field or trade. For example, a sprinkler system is installed by a sprinkler contractor and a fire alarm system is installed by an electrician and fire alarm contractor. Clean agent systems require the interaction of multiple trades including detection/controls, piping, mechanical shutdowns, and room integrity, as outlined above. As a result, having a strong specification is imperative for coordination. In addition to the design, third-party testing is recommended.
Clean Agent Fire Suppression Gas Refill and Recharge
If your building or facility has an Clean Agent fire suppression system in operation, you should already know that it is crucial to recharge (or refill) the system as soon as possible after every use or discharge. A properly working system should respond to even a small electrical fire within seconds. It works by immediately reacting and diffusing the fire before it has time to do more damage to your computer room, data centre, archives storage, etc.
Because the system reacted and put out the fire, it now is not as prepared to extinguish the next fire unless you get it recharged. With no Clean Agent gas to discharge, even another small fire could lead to great property loss or damage if it cannot be contained as quickly as it would with a working fire suppression system.
Clean Agent Gas Composition
Mixtures of Nitrogen, Carbon Dioxide, and any one of the Inert Gases including Helium, Neon, Argon, Krypton and Xenon. The most common composition is derived from a mixture of Nitrogen(52%), Argon (40%), and Carbon Dioxide (8%).
ARGONITE and IG55
Comprising of 50% Argon & 50& Nitrogen, it is naturally present in the atmosphere, therefore its greenhouse effect is nil and its ozone layer depletion potential is zero.
Based on a proprietary chemical from 3M called a fluoroketone. The full chemical name for this compound is dodecafluoro-2-methyl pentane-3-one. Its ASHRAE nomenclature – the way it is designated in the NFPA and ISO 14520 clean agent standards – is FK-5-1-12.
FM200 and SR200
Consist of 1,1,1,2,3,3,3-Heptafluoropropane, also called heptafluoropropane, FM200, HFC-227 or HFC-227ea (ISO name), as well as apaflurane (INN), is a colorless, odorless gaseous halo-carbon commonly used as a gaseous fire suppression agent.