There are various situations where integrating BAS products from multiple manufacturers can be useful. The issues involved with specifying BAS-to-BAS integration are somewhat similar to those for factory-mounted controls (as discussed last month) though with some added twists.
Why? The major circumstance for considering BAS-to-BAS integration is when adding on to an existing BAS. The simplest approach is to stick with the same manufacturer, though the client may prefer that the new work be bid out to multiple contractors/manufacturers.