NFPA-99 Practice Exam

What is NOT a requirement for metallic flexible joints used for vibration control in pipelines?

1. Able to withstand 1000 degrees

2. Provide brazing extensions to allow brazing into the pipeline

3. Received on the job site with certification of cleanliness

4. Suitable for service at 150 p.s.i. or above

The correct answer is: Suitable for service at 150 p.s.i. or above

The assertion that a requirement for metallic flexible joints used for vibration control in pipelines is not suitable for service at 150 p.s.i. or above is accurate because the design and specification of these joints generally focus on their ability to accommodate certain service conditions, including pressure ratings. For most applications, particularly those involving vibration control, flexible joints are designed to handle typical pressures encountered in pipeline systems, which often exceed 150 p.s.i. In this context, options regarding the ability to withstand high temperatures, the provision of brazing extensions, and cleanliness certifications are all pertinent considerations for ensuring the reliability and integrity of the pipeline system. High-temperature ratings might be necessary for applications where thermal expansion and operation at elevated temperatures are factors. Similarly, brazing extensions are required to facilitate proper joining methods, and certifications of cleanliness ensure that no contaminants affect the performance and safety of the pipeline system. Thus, while pressure ratings are essential, the specific mention of being "suitable for service at 150 p.s.i. or above" is not a typical requirement for metallic flexible joints meant for vibration control, making it the exception in this list.