Chainsaw and the fire service, keep it simple.
When I worked at the Oakland Fire department, we used a large power head, a Stihl 044 and/or MS 440 chain (No special saw… fire service design etc or special fire service chain). Saws were equipped with carbide tip chains using a 404-7 sprocket and .404” 20-inch bar. This set-up is for structure fires only(See below). We bought the Oregon generic carbide tooth semi chisel design in a large roll and made up our own chain. It worked great.
This way we could replace broken teeth and have a chain with a full set of teeth for every fire. We also sharpened the teeth with a carbide tooth sharpening jig. They were the saw of choice on every pitched roof op. The OFD regularly does vertically vent roof ops because of a large quantity of balloon frame housing stock.
Chain of choice (Below)
Bar of choice for the OFD (Below)