1. Heat-Flux Measurement - Issues Convection heat transfer effects (Schmidt-Boelter & Gardon) Non-uniform temperature distribution on sensor (Gardon) Different calibration methods by manufacturers Lack of suitable traceability to National Standards

2. Heat-Flux Measurement - Status No major break-through in sensor manufacture Calibration issues still persist (Sarkos, Hill & Johnson 1995)

3. Calibration Approach - NIST Detector Based (Flux) Blackbody radiation Source Based (Temperature) Flux measured Absorbs incident flux Flux traceability to National Standards Flux derived Effective emissivity Configuration factor Source temperature Factors: Calibration range, source temperature, view angle Establish equivalence

4. Resolving Calibration Issues Common Interest Group – Government/Users/ Manf. Evaluation of different calibration techniques Standard development efforts – ASTM/ASME Provide traceability to Primary Standards National Level

5. Resolving Calibration Issues Fire Laboratories Round-robin [NIST-BFRL/PL] International Standards Organization – ISO Flux Meter calibration standard Development – Ellipsoidal radiometer evaluation [SP, Sweden] International Level

6. Major Outcome of Collaboration Flux-scale calibration suitable when reflected component is large part of incident flux, source characteristics difficult to establish Temperature & flux scales equivalence demonstrated Low/moderate heat flux - convection effects important High heat flux – source effective emissivity important