Chemical Safety Evaluation & Testing

Chemical Compatibility & Thermal Stability Testing

DSC / ARC / SikaREX / DIERS-grade thermal characterisation — anchoring Stoessel criticality and SADT classification

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What this study delivers

Chemical Compatibility &
Thermal Stability Testing

Thermal stability and chemical compatibility testing form the foundational evidence base for any reactive-hazard or storage-segregation decision. Differential Scanning Calorimetry (DSC) provides mg-scale screening across −90°C to +600°C identifying exothermic onset, heat of decomposition, and reactive-trigger temperatures. Accelerating Rate Calorimetry (ARC) — including modern variants like Phi-Tec II, ESARC, and Thermal Hazard Technology (THT) systems — supplies adiabatic worst-case data with Phi-correction for vessel-class projection, generating Time-to-Maximum-Rate (TMRad) and Self-Accelerating Decomposition Temperature (SADT) per UN MTC Test H. Compatibility testing extends single-substance characterisation into binary and matrix combinations identifying dangerous interactions before they reach the storage facility — the discipline that prevents events like the West Fertilizer 2013 ammonium nitrate / combustible cellulose escalation, the Beirut Port 2020 catastrophe, and routine warehouse fires driven by unsuspected reactive pairs. Modern practice integrates calorimetric data directly into Stoessel criticality classification (Class 1–5), DIERS vent-sizing inputs, UN packing-group determination, and MOC reviews for any new-chemical introduction.

Chemical Compatibility & Thermal Stability Testing — Overview
Study execution

How the study is executed

A structured, facilitated process — from scope definition through close-out — producing defensible, actionable outputs.

Screening Calorimetry (DSC)

Conduct Differential Scanning Calorimetry per ASTM E537 / E2046 — temperature ramp typically 5-10°C/min from ambient to 400-500°C; identify exothermic onset temperature (To), peak temperature (Tp), and energy release (ΔH).

Adiabatic Calorimetry (ARC / Phi-TEC II)

Conduct adiabatic calorimetry — Accelerating Rate Calorimeter (ARC) or Phi-TEC II per ASTM E1981; measure adiabatic onset (To,ad), self-heat rate (dT/dt), pressure rise rate (dP/dt), and time-to-maximum-rate (TMRad).

Compatibility Matrix Testing

Conduct binary compatibility testing for each material pair (intentional contact or credible mixing scenario) per OSHA PSM / CCPS Reactive Chemicals; identify exothermic onset shift, gas evolution, and runaway potential.

Stoessel Classification

Apply Stoessel scenario classification (Class 1: TMRad >24h, low energy; Class 5: TMRad <8h, high energy with secondary decomposition); align with CCPS Process Safety Beacon and EFCE / IChemE guidance.

Safe Operating Window Definition

Define safe operating window — MTSR < To (onset minus safety margin typically 50°C); specify control philosophy with high-temperature trip, emergency cooling, and dilution / drown-out; align with HAZOP / LOPA / SIL allocation.

Documentation & PSI Compliance

Compile thermal stability report with raw data, classification, and design recommendations; include in OSHA PSM Process Safety Information (1910.119(d)); align with CCPS RBPS Reactive Chemicals Management element.

Chemical Compatibility & Thermal Stability Testing — Scope
Study scope

What the study covers in full

DSC screening across −90 to +600 °C identifying exotherm onset, ΔH, and thermal trigger
ARC adiabatic testing with Phi-correction for vessel-scale projection
Phi-Tec II / ESARC / THT calorimetric platforms for two-phase and gassy systems
TMRad calculation feeding SADT determination per UN MTC Test H
Stoessel six-class criticality assignment per CCPS framework
Heat-of-decomposition quantification with kinetic model fitting (Friedman, Kissinger, Ozawa)
Binary and matrix compatibility studies for storage segregation decisions
Process condition operating-envelope derivation with margin to runaway
Cryogenic-stability testing for low-temperature materials and intermediates
DIERS vent-sizing input data per the Omega method or simplified VSP correlations
Why it matters

Outcomes of Chemical Compatibility & Thermal Stability Testing

Thermal Instability & Decomposition Prevention
  • Prevents the West Fertilizer / Beirut-class reactive-storage catastrophic events
  • Identifies dangerous binary and matrix compatibility before warehousing
  • Defines defensible safe operating and storage envelopes
  • Anchors post-incident root-cause forensic analysis
UN TDG / OSHA PSM Thermal Defence
  • DIERS-compliant vent-sizing input data
  • UN MTC Test H SADT data for transport classification
  • Supports CCPS Reactive Chemicals Guidelines and OSHA reactive coverage
  • Provides UN packing-group and Class 4.1 / 5.2 classification basis
Safe Processing Temperature Envelope
  • Defines storage temperature limits with engineering basis
  • Sharpens MOC discipline for new chemical and formulation introductions
  • Supports DCS / SIS trip-setpoint and alarm-threshold derivation
  • Informs emergency cooling and quench-system design
Thermal Runaway Incident & Loss Prevention
  • Avoids the catastrophic loss profile of reactive runaway / decomposition events
  • Optimises storage temperature reducing energy consumption
  • Trims insurer loadings on reactive-inventory occupancies
  • Supports premium pricing on stability-validated products
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