Clean agent fire suppression gas is frequently used inside data centers. These gases may include Inergen, FM-200, ECARO FE-25, Novec 1230¹ and others. The gases provide fire protection without the use of water. This can be great option that cuts the damage and repair costs compared to water sprinkler. However compared to traditional sprinkler systems, the accidental discharge of the clean agent gas is far more likely and also very expensive. These systems can be triggered to release the gas and alarm the building by just lighting a flame, a release of refrigerant, or miscellaneous dust creation among many others .

All precautions should be taken to prevent an accidental discharge. We have all heard of an accidental gas release but at many sites, contractors still perform this type of work inside an active space. And when the proper steps aren’t taken prior to work starting, it’s not a matter of if it will happen but when it will happen. A costly and expensive gas discharge will not only initiate a building alarm that stops operations but also dispatch your local fire department. So, what can be done to prevent you from being front and center to explain why it cost $20, 30, 40, 50K+ to recharge agent, how did this occur and why weren’t provisions implemented to prevent an accidental discharge.

Risk is to be minimized inside the critical space at all times. This begins by executing “best practices” when it comes to having contractors performing construction or any maintenance service inside the clean agent protected space. The “best practice” is to have the fire system placed into a test status with the clean agent system discharge circuit disabled or “bypassed” via a keyed bypass switch with light indicator. Many existing legacy clean agent systems do not have a bypass switch installed. In the past, this was not a code requirement but with the new updated code, a bypass switch is now required.

If your site does not include a bypass switch, one can be easily installed and tested. Your staff should be fully trained on how to place the space into test and use the bypass switch. This is not to be limited to one person but also back up personnel so staff is available at all times to place the clean agent system in bypass and to re-engage to normal after the work task is complete. You can not depend on the contractor to operate your bypass switch and all other associated tasks to place the system and building in test. You will need to have trained staff to perform the required procedures at any time contractors are on site and that means sometimes in the middle of the night when emergency service is being performed.

All “change control procedures” are to include the clean agent bypass. Change control is a company internal procedure stating the task at hand and communicating to all company internal parties for comment and approval sign off. These procedures are to include the following at a minimum;

Prepare your change control procedure document and route/approve accordingly.





Contact your building monitoring company (if one exists) and place the building in test. This will prevent the deployment of the fire company to your site if an alarm is triggered. A time deadline will have to be given to the building monitoring company to automatically place the building off test and back on line. So, obviously you’re work tasks to be performed are to be fully completed prior to the deadline.

Utilize clean agent bypass switch to isolate the clean agent discharge assembly. You should also know that the clean agent bypass switch does not disable the smoke detectors. The possibility of a smoke sensor alarming may occur. All precautions should be made to minimize this possibility such as when copper brazing or refrigerant retrieval or leak is occurring. Refrigerant will set off the smoke sensors. If excessive smoke is generated within the area of a detector, the detector may have to be covered and a temporary smoke fan removal system installed. Also know that rooms with a raised floor, there may be an additional underfloor detector directly under the ceiling located detector. So pull up the floor tiles, locate detector and cover as needed. Any hot work should always be accompanied with a hand held clean agent extinguisher. Never use a powder type extinguisher.

When the clean agent bypass switch is used, the indicator light will energize and the clean agent panel will locally initiate an audible trouble alarm. This audible trouble alarm is to be silenced in the clean agent panel. At the same time, your main building Fire Alarm Control Panel (FACP) will receive a trouble signal. Check with your building manager on any required silencing. Your building manager should also receive your “Change Control” so prior knowledge of work task is known.

At this point, any required safety procedures are discussed and work can proceed.

When the work is completed prior to the building test deadline, the system can be placed back on line. The bypass switch indicator light will de-energize and the local and FACP trouble alarm will return to normal. Contact the building monitoring company to remove building from test.



The aferementioned are procedural examples that require a formal review and documentation on how they apply and execution in your specific data center. Mitigating the risk is a prime reason for implementing these suggested procedures. The cost to recharge the clean agent cylinders is expensive and to consider the cooling shuts off on gas discharge tends to make this event not only expensive but extremely stressful. It’s also another way to determine if your contractors are data center experienced is if they ask you prior to commencing work if the clean agent is in bypass. Here’s a good rule of thumb, if a contractor is working in the protected space, the clean agent system is in bypass all the time and every time.

Inergen is trademark of Ansul/Tyco; FM-200 & ECARO FE-25 are trademarks of Fike, and Novec 1230 is a trademark of 3M