When is it permissible to use a flexible hose instead of metal tubing in a system?

Using a flexible hose instead of metal tubing is permissible when it maintains identical flow characteristics. This is crucial in ensuring that the system's performance is not compromised. Flow characteristics refer to the ability of the hose to allow fluids to pass through without significant changes in pressure, turbulence, or velocity that could affect system efficiency.

Flexible hoses are designed to meet specific performance criteria and can be used effectively in applications where they match the necessary flow characteristics of metal tubing. This ensures that the system functions as intended without introducing potential issues such as leaks or reduced performance.

While space restrictions can sometimes necessitate the use of flexible hoses, it is not a standalone reason for their use when metal tubing could still be implemented with appropriate design considerations. Using flexible hoses strictly in emergencies is not a standard practice; instead, they should be used in specified applications where their properties are compatible with system requirements. Finally, using hoses simply due to the unavailability of metal tubing does not suffice; the choice should primarily focus on maintaining flow characteristics that meet operational needs.