Trends, changes in data center fire and life safety system design

Respondents:

• Bill Kosik, PE, CEM, BEMP, Senior Energy Engineer, DNV, Oak Brook, Illinois
• Matt Koukl, DCEP, Principal, Market Leader Mission Critical, Affiliated Engineers Inc., Madison, Wisconsin
• Kenneth Kutsmeda, PE, LEED AP, Global Technology Leader – Mission Critical, Jacobs, Philadelphia
• Ben Olejniczak, PE, Senior Project Mechanical Engineer, Environmental Systems Design Inc., Chicago
• Brian Rener, PE, LEED AP, Mission Critical Leader, Smith Group, Chicago
• Jonathan Sajdak, PE, Senior Associate/Fire Protection Engineer, Page, Houston

Bill Kosik, PE, CEM, BEMP, Senior Energy Engineer, DNV, Oak Brook, Illinois – Matt Koukl, DCEP, Principal, Market Leader Mission Critical, Affiliated Engineers Inc., Madison, Wisconsin – Kenneth Kutsmeda, PE, LEED AP, Global Technology Leader – Mission Critical, Jacobs, Philadelphia – Ben Olejniczak, PE, Senior Project Mechanical Engineer, Environmental Systems Design Inc., Chicago – Brian Rener, PE, LEED AP, Mission Critical Leader, Smith Group, Chicago – Jonathan Sajdak, PE, Senior Associate/Fire Protection Engineer, Page, Houston

What are some of the unique challenges regarding fire/life safety system design that you’ve encountered for such projects? How have you overcome these challenges?

Jonathan Sajdak: One key aspect and challenge of designing fire protection systems in data centers is the coordination with other disciplines. Whether its fire alarm or fire suppression related, there are typically items that need to be coordinated with mechanical, electrical, plumbing and architecture disciplines at a minimum.

One example that occurred on a project recently was having a clean agent system serving a space that was unable to pass the 10-minute enclosure integrity test; this is a standard test detailed in NFPA 2001: Standard on Clean Agent Fire Extinguishing Systems for total flooding clean agent systems. Our team had to coordinate with the architects to modify the door installation/sealing, ceiling grid design and size of the bi-directional vent to allow for pressure relief. After making these modifications, the test passed and the design criteria was achieved. There are some features that can be planned and designed for during the design phase, but it’s always possible that additional changes will be needed in the field once construction is complete. In this example, it’s important to make disciplines aware of the clean agent system acceptance testing requirements because certain aspects of their design may be impacted by the performance of the system.

What clean agent, aerosol, oxygen reduction or other fire suppression systems typically specified?

Matt Koukl: Fire suppression systems for facilities can vary depending on application, risk tolerance and insurance requirements. In addition, if the site is rural and does not have a plentiful source of water, there could be limitations to water supply to support a water-based suppression system. In a situation where there is not available water, AEI designs a clean agent system, which provides protection to the systems for multiple data halls.

Jonathan Sajdak: Two of the most frequently used clean agents in the design of data centers are HFC-227ea and FK-5-1-12, more commonly known as FM-200 and Novec 1230, respectively. One project we recently designed was the new IT building for an airport in Texas. For this facility, we designed and specified a Novec 1230 clean agent system for multiple reasons, including mitigation of residue upon activation, space available for storage of agent and how often the spaces are occupied. Other types of agents that can be considered in similar applications include Inergen and other inert gases such as nitrogen, argon and carbon dioxide.

Hydrogen fuel cell plant rendering. Courtesy: Jacobs

How have the trends in fire/life safety changed in data center projects?

Jonathan Sajdak: In recent years, fire protection systems used in data center facilities typically include preaction systems, clean agent systems and air aspirating smoke detection. One new technology to keep an eye on moving forward is hybrid fire extinguishing systems. NFPA 770: Standard on Hybrid (Water and Inert Gas) Fire-Extinguishing Systems, first published in 2021, is the standard for these systems that incorporate both water and inert gas into one suppression system. This standard is in the process of being introduced to and adopted by jurisdictions. One key design aspect to note for these systems is that an enclosure is needed to maintain the required concentration levels of the inert gas.

What fire, smoke control and security features might you incorporate in these facilities that you wouldn’t see on other projects?

Jonathan Sajdak: Arguably the most critical aspect of fire protection in data centers is detection. The faster smoke is able to be detected in the space, the greater the chance for containment and mitigating impact to the operation of the facility, which includes asset protection and business continuity. Some features and systems that you will see in data centers include air-aspirating smoke detection, gas detection (especially where batteries are stored) and ultraviolet/infrared detection via cameras. Using these detection devices, suppression systems such as clean agent and preaction systems are typically activated with the goal of suppressing and containing the fire.

Do you see any future changes/requests to the structural design of these buildings regarding fire/life safety systems?

Jonathan Sajdak: The biggest impact to the structural design of these buildings is the consideration of leakage and bi-directional ventilation for over- and under-pressurization where clean agent systems are provided. Both wall material and structural design can play a role in the rate of leakage along with the force walls can withstand when the pressure changes in the space upon releasing of the clean agent. In addition, bi-directional vents may have to be coordinated with the architect and structural engineer so that excess pressure can be relieved from the space.

How has the cost and complexity of fire protection systems involved with data center projects changed over the years? How did these changes impact the overall design process?

Jonathan Sajdak: One issue seen recently is the increased cost of materials and supply chain issues causing delays in procurement. An example is preaction systems, which are common suppression systems used for data center projects. Costs have increased for system materials and system components have longer lead times, particularly steel piping and fire alarm releasing panels. To optimize cost and performance for the owner while still meeting project schedule, exercises such as cost analyses should be performed to look at the use of one material or piece of equipment versus another. One example of this is comparing black steel and nitrogen in lieu of galvanized piping and dry air for preaction systems.

How have changes to codes, BIM and wireless devices/systems impacted fire and life safety system design for these buildings?

Jonathan Sajdak: One recent change in the 2022 edition of NFPA 13: Standard for the Installation of Sprinkler Systems allows for an increased C factor for dry and preaction systems using nitrogen. This change will help with hydraulic performance of the system and allow for designers to decrease pipe sizes in certain areas.

BIM software such as Revit and Navisworks have also allowed for improved coordination among engineering disciplines. Equipment and system elements can be modeled at a higher level of detail, allowing areas such as above ceiling plenum spaces to be optimized while also preventing clashes. For fire protection specifically, 3D families and components from clean agent systems, air sampling smoke detection and sprinklers can now be modeled to accurately represent their final constructed state.

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