Fire protection in cold storage environments is uniquely complex. With temperatures well below freezing, facilities rely on dry or pre-action sprinkler systems to keep water out of the pipes until activation. But while these systems prevent freezing, they introduce new risks—oxygen and moisture inside the pipes that can compromise system performance when it matters most.
That’s where nitrogen comes in. As an inert, ultra-dry gas, nitrogen eliminates oxygen-driven corrosion and moisture-based ice formation—the two leading causes of system degradation in cold storage settings.
Let’s explore why nitrogen inerting technology isn’t just an upgrade but a proven strategy for protecting cold storage facilities.
Key Challenges in Cold Storage Sprinkler Systems
Cold storage facilities well below 32°F/0°C present unique challenges for fire sprinkler systems. These facilities typically use dry or pre-action sprinkler systems where pipes are filled with pressurized gas instead of water to prevent water from freezing in the pipes. However, using standard compressed air in such systems can lead to two significant problems: corrosion and ice plug formation.
The air fed into dry and pre-action sprinklers contains about 21% oxygen and carries moisture (even if dried by a desiccant air dryer). Oxygen and residual water in the piping will cause internal rusting of steel pipes over time. In cold storage, any moisture can also condense and freeze at the entry point where warmer piping transitions into the freezer, forming ice plugs that obstruct flow.
FM Global (a leading insurance and standards organization) has found ice plugs in over 50% of the freezers it has examined in its field examinations, illustrating how common this issue is. Even a partial ice plug or corrosion buildup can impair sprinkler performance, reducing or completely cutting off water flow during a fire emergency. Corrosion and ice plug issues undermine system reliability, trigger false alarms, and drive up maintenance costs due to frequent repairs.
How Nitrogen Purging Prevents Corrosion and Ice
The core strategy for combatting corrosion and ice in cold storage fire sprinkler systems is to eliminate the oxygen and excess moisture inside the piping, which is precisely what nitrogen inerting technology does.
Nitrogen (N₂) is an inert, dry gas that makes up about 78% of air. By using a nitrogen generator to fill the sprinkler system, the oxygen level in the pipes can be reduced from 21% down to about 1–2%, essentially creating an oxygen-starved environment. With ~98% pure nitrogen in the pipes, the electrochemical rust reaction is halted. Without oxygen, steel cannot oxidize into rust. Any residual water from hydrostatic testing or condensation cannot corrode the metal because there is no dissolved oxygen to drive the reaction. This inert atmosphere effectively “passivates” the interior of the sprinkler system, dramatically slowing corrosion rates to near zero.
In addition, the nitrogen introduced is very dry. Modern membrane-type nitrogen generators produce gas with an extremely low dew point (around -70°F to -90°F). This far exceeds the drying capability of typical desiccant air dryers (which achieve about -40°F dew point) and easily satisfies FM Global’s recommendation to maintain the supervisory gas at least 20°F below the freezer temperature.
In practical terms, nitrogen purging removes moisture from the piping: as the system is initially filled and routinely vented, any water vapor is carried out, and the low-humidity nitrogen remains. Without humidity, there is no condensation to form ice. Using nitrogen prevents ice plug formation at the freezer inlet as the dew point of the gas is so low that even at subzero freezer temps, no frost or ice can precipitate inside the pipes.
Many nitrogen generator systems also incorporate automatic oxygen vents at the riser that continually bleed off a small amount of gas, purging out oxygen and moisture during normal operation. This fill-and-purge process ensures the internal environment stays mostly nitrogen and very dry at all times.
Why Nitrogen Generators are the Ideal Choice for Cold Storage
Unlike compressed air, nitrogen stops corrosion before it starts and prevents ice from forming inside the pipes. The result is a sprinkler system that stays clear, dry, and dependable—even in the harshest freezer conditions.
- Superior System Reliability: Nitrogen eliminates oxygen in dry and pre-action sprinkler systems, which is the primary cause of internal corrosion. This dramatically extends pipe life—often by 5x or more—and helps reduce sprinkler head blockages over time.
- Lower Maintenance and Repair Costs: By stopping corrosion at the source, nitrogen reduces the need for frequent pipe replacements, leak repairs, and emergency service calls. Compared to air dryers, nitrogen systems require minimal upkeep and have significantly lower annual maintenance costs.
- Ice Plug Prevention: Nitrogen has an extremely low dew point, keeping pipes dry and preventing moisture from freezing. Unlike compressed air systems, nitrogen eliminates the risk of ice plugs at freezer entry points, reducing nuisance alarms and ensuring reliable water flow during a fire.
- Code and Insurance Compliance: NFPA 13 now recommends 98% nitrogen in dry and pre-action systems for corrosion control, and FM Global approves nitrogen generators for cold storage applications. Using nitrogen helps facilities stay compliant with fire codes and insurer expectations—while improving safety and lowering risk.
Case Study: How a Cold Storage Facility Reduced Ice Buildup with an ECS Nitrogen Generator
A cold storage facility in the food service industry was experiencing frequent ice plug issues in its pre-action sprinkler system—particularly at the entry point to its -10°F freezer. Despite using a traditional Dry Air Pac™ system, quarterly inspections revealed consistent frost accumulation and partial blockages in the air supply line, leading to low air pressure alarms, false fire signals, and even emergency dispatches.
The facility partnered with Wayne Automatic Sprinkler and Engineered Corrosion Solutions (ECS) to replace the air system with an ECS Nitrogen Generator. After installation, nitrogen was used to purge oxygen and moisture from the system. After seven months, the results were clear: no ice buildup was found in any part of the sprinkler piping during routine inspections. The nitrogen generator eliminated ice-related issues and significantly lowered annual maintenance costs from an estimated $2,300 for the previous system to $450.
Ready to Protect Your Cold Storage Space?
Even small sprinkler failures can have major consequences in cold storage environments. Nitrogen-based systems eliminate the oxygen and moisture that create long-term issues like rust, leaks, ice plugs, and blocked water flow.
Facilities that switch to nitrogen see immediate benefits, from lower maintenance costs to dramatically improved system performance. Nitrogen generators ensure that when a fire emergency arises, the sprinkler system will operate as intended to protect personnel and valuable inventory. Adopting a nitrogen corrosion prevention solution for cold storage operations is an investment in safety, reliability, and long-term savings. It’s a strategy strongly supported by current fire protection best practices and guidelines.
Reach out today to learn how ECS nitrogen generators can protect your cold storage facility and keep your fire sprinkler system operating at peak performance.
