Standard USP 1174 measurements with the GranuHeap

What Is the Angle of Repose?

The Angle of Repose is a historic measurement that provides a fast and easy way to get a classification of powders. When poured, granular materials and powders naturally form a heap whose angle depends on the properties of the material (inter-particle friction, cohesive forces). Therefore, measuring the angle of the heap, commonly referred to as the Angle of Repose (AOR), provides information that can be used to predict flowability of the powders. The Angle of Repose evaluation methodology is covered by several standardized protocols, and particularly by the USP1174.

Measuring According to USP1174

The new GranuHeap software now allows to perform USP1174 Angle of Repose measurement. The USP1174 procedure is fully integrated in the software, thus requiring no preliminary knowledge of the standard. The operator is guided through all the steps, minimizing the risk of errors and guaranteeing the correct execution of the standardized procedure. A camera takes a picture of the heap, then processed by an image processing algorithm to accurately determine the Angle of Repose. The repeatability is thus improved by reducing the inherent operator-to-operator variability of the heap height measurement.

Secure and Traceable Data Handling

Moreover, the measurement data are stored electronically by the software and secured by a CFR 21 part 11 compliance for data integrity. This prevents errors that can arise from manual reporting of the results. Also, the heap pictures can be accessed after the measurement for quality control checks. Measurement reports can be exported to be included in the quality control documentation.

Combining Standard and Advanced Characterization

Using the GranuHeap to do USP1174 tests also allows to go further in the understanding of the powder properties by combining the standard test with a GranuHeap advanced characterization. Indeed, the GranuHeap instrument has been designed as a major improvement of the classic standard procedures by providing repeatable and accurate evaluation of the Angle of Repose thanks to the use of a video camera and an image processing analysis. Moreover, the shape of the heap is also characterized, which gives access to a metric quantifying the cohesiveness of the powder, the static cohesive index. With the new GranuHeap software you get the best of both worlds: the standard procedure for quality control and the advanced characterization to go deeper into the understanding of the powder behavior.

Want to explore USP1174 compliance and powder flow standardization in pharma?

Join our free webinar on April 15, 2025 (4–5 PM CET): “Standardizing Powder Flow Characterization in Pharma: Ensuring Compliance & Efficiency”

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