Abstract: Methods of evaluating a fluid condition may include stroking a valve member and measuring a force acting on the valve member during the stroke. Methods of evaluating a fluid condition may include measuring a force acting on a valve member in the presence of fluid flow over a period of time and evaluating at least one of the frequency of changes in the measured force over the period of time and the magnitude of the changes in the measured force over the period of time to identify the presence of an anomaly in a fluid flow and, optionally, its estimated location. Methods of evaluating a valve condition may include directing a fluid flow through a valve while stroking a valve member, measuring a force acting on the valve member during the stroke, and comparing the measured force to a reference force. Valve assemblies and related systems are also disclosed.

Abstract: A work platform (10) for performing work operations on an object such as roof construction work including an upper surface (15A) for working on the roof and a lower surface (15B) for storage of work material, the step between the work surfaces (15A, 15B) comprising an elongate material transfer section (19), and the upper work surface (15A) including a covered roof access section (11). The platform can also be used for access to perform maintenance work on aircraft, railway carriages, etc. The invention also provides method of performing work operations utilising the work platform (10).