What is a firestopping Engineering Judgment (EJ)? An EJ is required where there is no specific third party tested and classified firestop system available for an installed condition. EJs in firestopping are necessary on almost every construction project. The fact is, it is impossible to test firestop installations for every conceivable condition that may currently exist or arise in the future, so the best solution in many cases is a firestopping EJ. If it’s properly done there is technically nothing wrong with an EJ, “properly” being the key word. But know this, getting an EJ approved through the inspector or architect may not be easy. Fortunately, the International Firestop Council has published guidelines for such EJs and if followed should make approvals much easier.