May 26, 2010
Clean Agent Gaseous Fire Suppression Systems
Fires in data centers can put personal safety, property and business operations in danger, resulting in losses that can extend beyond the occurrence of the actual fire. Repairing or replacing damaged equipment is expensive and may require significant business downtime, which is also costly. For a typical computing infrastructure, business downtime impact is estimated to be $42,000/hr; downtime impacts for companies relying entirely on telecommunications technology, such as online brokerages or e-commerce sites, can reach $500,000 per hour or more. Since data centers have an essential role in powering our e-commerce infrastructure, protecting these facilities is critical to ensure business continuity and minimize revenue loss.
Gaseous fire suppression systems (also referred to as clean agent systems) are rapidly becoming a preferred extinguishing option for data centers. The term ‘clean agent’ is defined by the National Fire Protection Association (NFPA) 2001 as an "electrically nonconductive, volatile, or gaseous fire extinguishing that does not leave a residue upon evaporation." These systems are utilized to protect high value assets, such as computer server rooms, where a high level of fire protection is required but the use of water or other suppressant agents may cause excessive collateral damage.
These fire suppression systems extinguish fires using a gaseous agent that is able to permeate into cabinets and obstructed area, absorb the surrounding heat, and deprive the fire of oxygen. The gaseous agents are non-conductive and non-corrosive, making them safe to use around live electrical equipment. The agents also leave no residue so there is no clean up following a discharge and business is able to be quickly resumed. Several types of facilities can benefit from the use of clean agent systems:
Computer rooms
Sub-floors
Control rooms
Tape storage rooms
Critical file storage rooms
Telecommunications facilities
Clean rooms
Electric switchgear
Vaults
Process equipment
Engine test cells and other test bays
Libraries, museums, art galleries, archives
For clean agents to work effectively, the rooms they protect must be constructed in such a way as to contain the clean agent until it has had time to fully extinguish a fire. NFPA 2001 refers to this containment period as the "Soak" period and code requires that the clean agent stay inside the room for 10 minutes to accomplish "Soak". Containing the clean agent requires the following procedures:
Exterior walls must be constructed from slab to structure above, bedded, and taped to be air tight.
Conduit and other pipe penetrations must be sealed so that there is no escape of air.
Conduits that originate outside of the protected area must be sealed inside the conduit, much as you would in an explosive environment.
Doors must be equipped with smoke seals and sweeps.
HVAC ducts that penetrate the exterior of the room must be equipped with smoke dampers that close upon release of the clean agent.
Special audio/visual devices are mounted both inside and outside the room to warn people to not open the doors.
In addition to clean agent implementation, data center managers should also try to minimize combustible materials, such as furniture, data storage media, and paper, and they should seal penetrations for cabling, air handling, and other components with fire-rated sealants.
The benefits of a gaseous fire suppression system are numerous. The system extinguishes fires quickly, and when a fire is extinguished quickly it ultimately saves you money by lowering repair costs, downtime and damage. Gas fire suppression systems can also help to protect your staff by adding another element to your fire protection initiatives. Finally, when compared to Halon extinguishing methods’ effect on the environment, clean agents are superior and have zero effect on the earth’s stratospheric ozone layer.
References:
http://zodiaq.fr/FE/en_US/science/expert_view_lowery.html
http://www.buildings.com/Magazine/ArticleDetails/tabid/3413/ArticleID/6588/Default.aspx
http://www.facilitiesnet.com/firesafety/article/Clean-Agent-Suppression-Systems-Fire-Fighting-Strategies-for-Mission-Critical-Facilities--3517
http://www.thefreelibrary.com/Benefits+of+a+Gas+Fire+Suppression+System-a01073935778