Sector·2 min read
Cold Storage and Ammonia Refrigeration Fire Safety
Cold stores have a contradictory fire profile: although the temperature inside is low, the fire load is high — cartons, plastic packaging, wooden pallets, and combustible product are stacked on high racks. Ammonia (NH3) refrigeration systems hold a toxic and, at certain concentrations, flammable gas in the machine room; the sandwich panels (PIR/PUR foam) used for insulation can carry fire rapidly along the envelope; and because a classic wet sprinkler can freeze and go out of service, a dry or preaction system must be selected. This article covers the real risks in cold stores, the measures to take, and the recommended suppression systems (dry/preaction sprinkler, ESFR, ammonia gas detection, and machine-room protection).
A-Pro Engineering
Cold stores have a contradictory fire profile: although the temperature inside is low, the fire load is high — cartons, plastic packaging, wooden pallets, and combustible product are stacked on high racks. Ammonia refrigeration brings a toxic/flammable gas, flammable sandwich panels bring envelope-spread risk, and freezing disables wet sprinklers. This article covers the real risks, measures, and recommended suppression systems.
Risk: low temperature ≠ low fire risk
- Product + carton/plastic packaging + wooden pallets on high racks — dense fire load,
- Flammable sandwich panel (PIR/PUR) in insulation — hidden/rapid spread along the envelope,
- Ammonia (NH3) — toxic and flammable in the 15-28% range (machine room),
- Freezing — classic wet sprinkler freezes, bursts the pipe, disables the system,
- Smoke and heat build up rapidly in the enclosed/insulated volume.
Measure: ammonia machine room
- Ammonia gas detection in the machine room,
- Automatic ventilation + emergency shutdown on a leak (safe stop),
- Equipment grounding + keeping ignition sources away,
- Machine room as a separate compartment; clean-agent suppression for electrical if needed.
Gas detection is as critical as fire detection in this facility.
Measure: the right sprinkler against freezing
Wet sprinklers freeze in freezer volumes; instead:
- Dry-pipe or preaction system — pipes filled with air/nitrogen, water enters only on detection,
- Preaction provides a double interlock against false activation — preventing accidental water discharge.
We covered valve-set selection in our dry/deluge/preaction article.
Measure: insulation panel and compartmentation
- Non-combustible / fire-rated panel where possible,
- Fire-stop at panel joints and service penetrations,
- Dividing the building into compartments.
The wrong panel nullifies even the best sprinkler system.
Recommended suppression systems
| Area | Recommended system |
|---|---|
| Storage volume (cold/freezer) | Dry-pipe / preaction sprinkler |
| High-rack dense stacking | ESFR / in-rack sprinkler |
| Ammonia machine room | Gas detection + ventilation + emergency shutdown |
| Machine-room electrical equipment | Clean-agent gas (if needed) |
| Early detection | Low-temperature reliable detector + aspirating |
We covered ESFR/in-rack selection in our ESFR article.
Summary
Cold-store fire safety is built along three axes: securing the ammonia machine room with gas detection + ventilation + emergency shutdown, protecting the store with freeze-resistant dry/preaction sprinkler (and ESFR/in-rack on high racks), and cutting passive spread with insulation panel + compartmentation. All are based on NFPA 13 + EN 12845/BYKHY (and refrigeration safety practices). For a related risk see our chemical storage article. At A-Pro Engineering we design dry/preaction sprinkler, ESFR, gas detection, and machine-room protection for cold stores in an integrated way; contact us for your project.
This content is for information purposes. Binding design must be done on a project basis based on store temperature, rack height, packaging type, refrigerant, and actual facility conditions, together with NFPA 13, NFPA 2001, EN 12845, relevant refrigeration safety regulations, and the current edition of BYKHY.
© 2027 A-Pro Mühendislik. This is original technical content produced by A-Pro Engineering; all rights reserved. Copying, reproducing or republishing it in whole or in part without attribution and permission is prohibited.
Frequently asked questions
Is there a fire risk in a cold store — isn't the temperature already low?+
Low temperature does not prevent fire; on the contrary, cold stores have a high fire load. Besides the stored product, cartons, plastic packaging, and wooden pallets form a dense combustible mass, and these are stacked on high racks. In addition, the flammable sandwich panels used for building insulation and the refrigeration system's electrical/compressor equipment carry extra risk. When a fire breaks out, the low temperature does not slow the flame; on the contrary, smoke and heat build up rapidly in the enclosed, insulated volume. So cold stores must be treated as a serious fire risk despite their low temperature.
Why is ammonia (NH3) refrigeration risky and how is it protected?+
Ammonia (NH3), widely used in industrial refrigeration, is both toxic and flammable within a certain concentration range (roughly 15-28% in air); a leak creates both a poisoning and a fire/explosion risk in the machine room. For protection, ammonia gas detection in the machine room, automatic ventilation and emergency shutdown (safe system stop) on a leak, equipment grounding, and keeping ignition sources away are applied. The machine room is treated as a separate compartment; clean-agent suppression is considered for electrical equipment if needed. Gas detection is as critical as fire detection in this facility.
Which sprinkler system is used because of the freezing problem?+
Classic wet (filled-pipe) sprinklers cannot be used in cold-store and freezer volumes; water in the pipes freezes, bursts the pipe, and disables the system. So a dry-pipe or preaction system is preferred; the pipes are normally held filled with pressurised air/nitrogen, and water enters the line only when detection/a sprinkler opens. Preaction also provides a double interlock against false activation — preventing the damage that accidental water discharge would cause in a cold store. We covered valve-set selection in our dry/deluge/preaction article; the right choice is made per store temperature and sensitivity.
Why do flammable insulation panels (sandwich panels) matter?+
Sandwich panels are used for insulation on the walls and ceiling of cold stores; panels filled with flammable foam (PIR/PUR) form a hidden and rapid spread path along the envelope during a fire and make suppression harder. So, where possible, non-combustible or fire-rated panels (appropriate reaction class) should be preferred; panel joints and service penetrations should be properly sealed (fire-stop); and the building should be divided into compartments. Panel selection is a passive measure as decisive as active suppression; the wrong panel can nullify even the best sprinkler system.
Which suppression systems are recommended in a cold store?+
Freeze-resistant dry-pipe or preaction sprinkler for the storage volume; ESFR or in-rack sprinkler for high-rack dense stacking (in freezers, in-rack is often preferred due to ESFR limitations). For the ammonia machine room, gas detection + ventilation + emergency shutdown and, if needed, clean-agent suppression for electrical equipment. For early detection, detectors and aspirating systems that operate reliably at low temperature are preferred. The right set is designed in an integrated way per store temperature, rack height, packaging type, and refrigerant.
Which standards govern cold stores?+
For cold stores and high-rack storage, NFPA 13 (dry/preaction and ESFR/in-rack criteria) and EN 12845/BYKHY for water demand are the basis. On the ammonia refrigeration side, machine-room safety, gas detection, and ventilation are handled per relevant refrigeration safety regulations (e.g. IIAR practices); NFPA 2001 applies for clean-agent suppression of electrical areas. The fire reaction class of insulation panels is selected per relevant building/material standards. In Türkiye, design is based on these standards together with BYKHY. For a related risk see our chemical storage article.
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