What percentage of failure of installed field devices of one type constitutes a batch failure of the entire supplied devices as a project?

Is there any regulation or standard that governs this?

Is there any segregation between the way process and fire and gas devices are treated with respect to batch failures?

 

Reputable manufacturers pre-test their equipment prior to shipping. Some end-users even pretest the hardware upon receipt.

Get your on inspection methodology sorted through, and catalog the data, with qualified specialists. Only then you can start talking about failures of any sort.