Overview - What ISO 4112:2025 covers
ISO 4112:2025 provides guidance for the measurement of the temperature of grain stored in bulk (cereals and pulses) in silos, horizontal warehouses and other storage buildings. The standard describes the principle of placing thermometric probes throughout a grain mass, the required apparatus and sensor types, probe layouts, measurement procedures, digital display/recording, and basic calibration and record-keeping expectations. The 2025 edition updates probe layouts, thermometric systems and adds guidance on wireless/networked monitoring.
Key topics and technical requirements
- Scope and principle
- Monitoring bulk grain temperature using a network of thermometric probes to detect hotspots and prevent spoilage.
- Apparatus and system components
- Thermometric cables/probes (rigid tubes or flexible cable), thermometric instruments, and a thermometric system (computer, communications, electronics).
- Probes must be resistant to fumigants and rodents; flexible cables in silos should be anchored.
- Sensors
- Thermistors, thermocouples or digital sensors capable of detecting temperature changes of about 0.5 °C; working range up to 70 °C.
- Probe response time when buried: ≤ 3 minutes to reach steady reading.
- Probe layout and placement
- Horizontal warehouses: probes no more than 5 m apart horizontally; sensors vertically spaced ≤ 2 m. Typical placements: 0.3–0.5 m below grain surface, 0.5–0.8 m above floor, ~0.5–0.8 m from walls.
- Silos: ring arrangement with horizontal spacing ≤ 5 m, vertical spacing ≤ 3 m; placements: 0.3–0.5 m below surface, 0.8–1.0 m above floor, 1.5–2.0 m from walls.
- Short-term storage: divide area ≤100 m² with five measuring points (center + four corners) and layer probes by bulk height.
- Measurement procedure
- Frequency depends on storage conditions: e.g., every 24 h under unfavorable conditions, reduced (e.g., weekly) when dry/cold.
- For ventilated warehouses: initial reading, ventilate ~30–45 minutes (depending on height), measure inlet air, then take a corrected second reading per clause 6.2.2.
- Records and calibration
- Maintain temperature records and perform regular calibration of sensors/instruments (see clause 7).
Practical applications - Who uses this standard
- Grain storage operators and silo managers for routine temperature monitoring and hotspot detection
- Agribusiness quality managers and food-safety personnel to reduce spoilage and maintain commodity value
- Equipment manufacturers and integrators designing thermometric probes, monitoring systems and wireless solutions
- Engineers and consultants specifying probe layouts for new or retrofitted warehouses
- Auditors and regulators verifying compliance with best-practice bulk grain management
Related information
- ISO 4112:2025 lists no normative references; it was prepared by ISO/TC 34 (Food products). For implementation, consult ISO resources (ISO OBP) and national technical committees for local guidance.
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