Texas CNG(Compressed Natural Gas) Driver Practice

What is the required discharge flow rate for a pressure relief device?

1. Below the maximum pressure rating

2. Exactly the same as the inlet flow rate

3. That required for the capacity of the container

4. Higher than the operational pressure

The correct answer is: That required for the capacity of the container

The required discharge flow rate for a pressure relief device is determined by the capacity of the container it is protecting. This is crucial because the flow rate must be sufficient to safely release gas or liquid in the event of a pressure build-up, ensuring the pressure doesn't exceed safe operating limits. If the flow rate were lower than what's necessary for the capacity of the container, there could be a risk of overpressure and potential failure of the system, leading to safety hazards. Having a discharge flow rate that corresponds to the container's capacity ensures that, during an emergency situation like an overpressure event, the pressure relief device can function effectively to manage and relieve excess pressure, thereby safeguarding both the container and the surrounding environment. If the flow rate is not adequately matched to the container's capacity, it poses a significant risk to safety and operation. This underscores the importance of correct flow rate calculations in the selection and installation of pressure relief devices.