Clean Agent Systems are the best fire protection system for your server rooms. For this suppression system to work properly, your server room construction needs to be specifically designed to limit leaks and hold the gaseous agent.
In reports from the NFPA, when automatic extinguishing equipment was reported present, sprinklers were reported in 72% of the fires. Wet-pipe sprinklers were reported for 90% of the fires with sprinklers present, compared to 7% for dry-pipe sprinklers and 3% for other sprinklers.
When wet-pipe sprinklers were present, 56% of fires were reported as too small to activate operational sprinklers. Clean agent systems can activate faster than traditional wet-pipe sprinklers and, since they do not use water, will not damage your electrical equipment when used. Debris, smoke, and water clean-up wreaks havoc on electronic gear. It also prevents your business from getting back to business as usual.
Server Room Construction for a Clean Agent Suppression System
Server rooms are generally constructed with the perimeter walls extending from the true ceiling (as opposed to drop ceilings and the like) to the lowest structural unit, either the floor itself or the concrete slab underneath the floor. This creates a fire rated barrier for the room and reduces the leaks a room will have in an Integrity Fan Test.
Server rooms should be prepared for a clean agent suppression system by inspecting the walls and slab for leakage points, sealing them with fire retardant materials, and fitting the doors with pressure seals around the jams and thresholds.
When constructing a server room, your contractors should ensure the following points are followed to allow for a clean agent suppression system.
Doors & Windows
- All doors must have a threshold and sweep installed
- Egress doors should swing out of the protected space
- Doors may require weather stripping around the jam to ensure an air tight seal
- Latching mechanisms are necessary and door closures are required
- If doors to the server room must remain open, an electromagnet door holder will be required which can be released prior to agent discharge
- All types of windows, pass through, or openings must be fire caulked and sealed
- Porous block walls must be sealed from slab-to-slab to prevent gas from leaking out of the block; two or three coats of paint are typically required
- Server rooms should be enclosed with wall partitions that extend slab-to-slab; in areas where this is not possible, all ceiling tiles should be clipped and openings caulked
- All walls should be caulked around the inside perimeter of the room where the walls rest on the floor slab and the walls intersect with the ceiling slab above
- Upgraded, noncombustible ceiling tiles are recommended
- Drywall should be caulked at the joints of the walls and floor, and at the roof or floor above
- Any penetration to the walls, including conduit, cable trays, outlets, switches and wire troughs, must be fire caulked and sealed
- If a raised floor continues out of the protected space, bulkheads must be installed under the floor directly under the partitions; these bulkheads must be caulked top and bottom
- All floor drains should have traps which are designed to have water in them at all times
- To ensure the protected area is air tight, dampers may be required in the ductwork at the perimeter walls of each protected space
- Dampers must be spring loaded or motor operated to provide 100% air shut off
- A 5% minimum leakage requirement must be met so the dampers must be UL #5555
- With clean agent fire suppression, the HVAC will be shut down prior to discharge, self-contained HVAC units may continue to run (if included in design calculations)
- HVAC shut down control relays should be installed to within 3 feet of each unit
- All exhaust fans should be dampered; fire alarm system control relays are used to shut down any fans
- All fresh air intakes should be dampered and closed using fire alarm system control relays
Power and Interface Wiring
- 120 VAC dedicated 15 AMP circuit to the suppression control panel is required
- Power to all dampers – control relays within 3 feet of damper
- Fire alarm monitoring – contacts for alarm, supervisory and trouble conditions are available within the fire control panel; connection is handled by your fire system contractor
- Purge system control wiring to HVAC units and exhaust fans are interfaced with fire alarm system control panel; connection is handled by your fire system contractor
Pressure Relief Vents
While ensuring that your server room is sufficiently sealed to contain the suppression agent for at least 10 minutes, you also have to take into consideration the maximum amount of pressure the room’s construction can withstand. The suppression agent is released with force, in a sealed room, if not calculated properly the pressure could be higher than the room can withstand. NFPA 2001, Section 5.3.7 states, “if the developed pressures present a threat to the structural strength of the enclosure, venting shall be provided to prevent excessive pressures.” Your suppression system designer should calculate Peak Pressure equations for your server room to determine if you need Pressure Relief Vents installed.
In addition to calculating if a pressure relief vent is necessary, and what size it should be, your designer should also calculate the leakage rate for the vent to ensure it will open and close at the correct pressure and will vent the proper amount of pressure to outdoors.
If Pressure Relief Vents need to be installed, here are some guidelines for optimizing performance:
- Install vents as high as possible so that the lighter air, not the denser agent, is vented
- Vents should open at pressures no lower than .007 PSI (50 Pa) so they don’t open unintentionally under normal HVAC pressures and no higher than .02 PSI (100 Pa) so the pressure is vented early enough to prevent it from becoming excessive
- Specify the correct direction for venting with the Pressure Relief Vent. Inert agent discharges always create positive pressures and must have venting out of the enclosure, but halocarbons may create positive and/or negative pressures creating a need to be vented in either direction or both, depending on the agent and the humidity
- All Pressure Relief Vents should be inspected annually to confirm they will open according to their specifications and to verify that the vent path to outdoors has not been accidently restricted
Keeping your project on schedule can be a challenge. Planning, communicating and coordinating with the different trade professionals is important and one set-back can cause a ripple effect for others. Here are a few items Electrical Contractors can check off the list to keep the fire protection part of the plan on moving forward.
- Have background CAD Drawings available
Your fire protection project starts with installation drawings which overlay with the project’s background CAD drawing. The design of a fire protection project cannot begin until these original drawings are received. When you select your Life Safety partner, have your project’s CAD drawings ready to hand over so that the fire protection design can begin immediately. To delay the start of the design can lead to slow submittals, unnecessary delays, or even missed deadlines.
- Coordination with other trades
To have a successful fire protection design, your Life Safety partner will need to coordinate efforts with other trades during construction. Successful communication between trades will limit delays and errors in project delivery. For example, the sprinkler contractor needs to communicate the number and locations of sprinkler points to be monitored. It is recommended that your elevator contractor and fire alarm contractor meet early in the schedule to discuss the interface. Many issues and delays can occur if miscommunication occurs between the fire alarm and HVAC professionals, so A1 recommends that you use your fire alarm contractor to supply and install the system duct detectors. This cuts down on the opportunity for problems and delays, and allows the duct detectors to be programmed in a way that they can be reset at the fire alarm panel.
- Phone Company
We all know utilities move at their own pace. Waiting on the phone company to provide a dedicated line for your fire sprinkler monitoring system can be frustrating and cause an unnecessary delay. By utilizing cell monitoring you can cut out the phone company altogether. Take back control of your project. Your Life Safety partner can install a cell dialer during construction.
Your Fire Alarm panel requires a dedicated power line with 120-volt circuit with a breaker lock marked “fire” in red. Without this power line installed and properly marked, your Life Safety partner cannot move forward with the fire alarm panel install and programming. Ensure that your power is properly run before your Life Safety partner is scheduled to perform the fire alarm install.
- Check all Circuits
This is another item that needs to be completed before your Life Safety partner can begin installation. Your electrician should check all circuits to ensure they are free of trouble, no grounds, opens or shorts. If your fire alarm panel senses these troubles it will not work properly, your Life Safety partner will have to spend valuable time rechecking all lines for the problem which can delay the schedule.
- Communicate Permit Notes/Changes
When permits are returned with comments it is imperative that these notes be passed back along to your subcontractors including your Life Safety partner. If changes are required but not implemented, you can fail your final walk-through and delay occupancy. Even small changes can take time and cause extra expense if they have to be corrected after all work is complete; however, the delay and expense can be minimized if the changes are communicated during construction.
- Communicate changes to project schedule
Changes to your project schedule need to be communicated to your Life Safety partner and other subcontractors as soon as possible. If you are changing your project to a phased project, experiencing delays, or accelerating your project getting all of your partners on-board with that change as quickly as possible can be the difference in successfully meeting your new timeline.
- 100% Pre-Check
You should test 100% of the fire alarm devices before the AHJ arrives for the final inspection. This ensures a successful final and occupancy. More importantly, it provides confidence that the fire alarm system will work in the case of an actual emergency.
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