[OpenPlantModeler C#]Dose anyone knows how to get elementid from IECInstance?

I found a way to get all pipe of current plant in OPM SDK's example as follow :

ECInstanceList pipeInstances = DgnUtilities.FindInstancesAndLoadRelated("PIPE", false, "PIPING_COMPONENT_HAS_PORT", true);
if (pipeInstances != null && pipeInstances.Count > 0)
{
    foreach (IECInstance pipeInst in pipeInstances)
    {
        //do something
    }
}

I could get most EC value in the pipeInst,but i can't get ElementId from it.Does Anyone knows how to get ElementId from it or have an easy way to get all pipe's ElementId?