In industrial refrigeration, ammonia (NH₃ / R717) remains the natural refrigerant of reference. With zero GWP (Global Warming Potential) and zero ODP (Ozone Depletion Potential), it is a cornerstone of sustainable cooling systems worldwide.
However, although refrigeration circuits operate in closed loops, the engine room environment itself must be designed to ensure safety, reliability, and worst-case exposure scenarios.
Ventilation in NH₃ installations is not designed only for normal operation — it must be designed for chemical uncertainty.
1. The true chemistry of a machine room in the food industry
In standard operation, ammonia concentrations in a properly ventilated machine room remain very low. But the industrial reality of slaughterhouses and agri-food factories is much more complex.
These facilities are subject to intensive and regular cleaning protocols, often daily. The washing phases involve highly alkaline leaching products — caustic soda, concentrated detergents, basic degreasing foams — whose vapours invade the entire machine room environment. It is precisely during these phases that the extractors operate at full speed to remove chemical vapours, aerosols and moisture laden with cleaning residues.
- Chronic alkaline attack of the cleaning phases High pH leaching products, widely used in slaughterhouses and cutting plants, generate vapours and aerosols deposited on all surfaces in contact with extracted air. For metal equipment, this repeated exposure weakens protective coatings, initiates underlying corrosion phenomena and gradually reduces the mechanical strength of the components.
- Localized NH₃ interaction with moisture In the case of chronic micro-leaks, aging seals, maintenance operations or condensation areas, ammonia can react with moisture to form ammonium hydroxide. This alkaline compound can gradually attack galvanized coatings and, over time, contribute to pitting phenomena on some stainless steels — especially in wet and stagnant areas.
- Oil and dust vapour deposits Oil vapors from the compressor mix with cleaning residues, moisture, and airborne particles to form stubborn deposits on the propellers. On metal fans, these deposits accelerate surface degradation, mechanical imbalance, and long-term wear.
2. Engineering for worst-case scenarios
Industrial ventilation in NH₃ plants is a safety feature. Regulations such as ICPE 4735 in France require ammonia detection systems to trigger immediate extraction. In emergency mode, fans must accelerate reliably and operate in potentially aggressive atmospheric conditions.
An extractor degraded by months of exposure to alkaline detergents cannot guarantee the required performance at the critical moment.
3. Why Polypropylene Offers Intrinsic Chemical Immunity
SEAT ventilation extractors are made of high-density polypropylene (PP). Unlike coated metal systems, polypropylene does not depend on surface protection. The material itself is chemically inert.
- Absolute immunity to alkaline corrosion
Full resistance to highly alkaline leaching agents, dry or wet ammonia, cleaning acids, detergents and industrial vapors in the temperature range of refrigeration environments. No coating to degrade, no oxidation layer to compromise — no matter how often and how intense the cleaning phases are. - Aerodynamic stability over time
Polypropylene propellers maintain their smooth airfoil for 15 to 20 years, ensuring stable airflow and consistent performance — even after thousands of cleaning cycles. - Thermal reliability
Our PP extractors operate from −20°C to +80°C without brittle fractures or weld fatigue issues sometimes associated with metal assemblies subjected to repeated temperature cycles.
4. Total Cost of Ownership (TCO): A Long-Term View
In industrial refrigeration, the purchase price of a fan is only a fraction of its life-cycle cost.
| Performance Measurement | Traditional Metal / Stainless Steel | SEAT Polypropylene |
|---|---|---|
| Typical Lifespan | 5 to 8 years | 15 – 20 years |
| Maintenance Needs | Periodic corrosion treatment | Standard inspection only |
| Replacement cycles (20 years) | 2 – 3 | 1 |
| Weight | Heavy | ~40% lighter |
| Reliability in cleaning phases | Degrades over time | Remains constant |
| Emergency reliability | May degrade over time | Remains constant |
By eliminating multiple replacement cycles and reducing maintenance downtime — especially critical in high-production slaughterhouses and food factories — polypropylene systems typically achieve a return on investment within the first 3 years of operation.
Most importantly, they maintain performance consistency — a critical parameter in regulated environments.
5. Safety, compliance and peace of mind
A corroded fan isn't just a maintenance issue — it's a safety risk. If the integrity of the propeller or the rigidity of the housing is compromised by months of exposure to leaching products, emergency extraction performance may no longer meet design specifications during a leak event.
In food and beverage environments, where cleaning phases are a daily operational reality and not a one-off event, the chemical robustness of ventilation equipment is a prerequisite — not an option.
Polypropylene offers intrinsic immunity without reliance on coatings or periodic surface protection.
Conclusion: Designing for industrial reality
Ammonia refrigeration systems are designed in a closed loop. The machine rooms of slaughterhouses and food factories, on the other hand, are exposed to highly alkaline leaching products, humidity, industrial fumes and potential leakage scenarios on a daily basis.
Ventilation must therefore be designed for durability, reliability and resistance to recurrent chemical aggressiveness — not just for nominal operation.
With more than 55 years of expertise, SEAT Ventilation supplies 100% polypropylene extractors specifically designed for these most demanding industrial environments.
