Can someone help me understand the requirements of 450.23 for putting an oil filled transformer on a roof? Examples would be extremely apricated. We have a 1500kVA transformer with FR3 oil and the client is insured by FM. I am just having a hard time understanding how to provide containment. Section 5-4 Transformers of FM Global Property Loss Prevention Data Sheets directs us to provide containment, but then goes on to state that the scope of the document is not to give the requirements for Environmental Protection and directs you to IEEE 980 Guide for Containment and Control of Oil Spills in Substations.