 Do I need hydrants to basement level during construction? So clause E1.9 says required hydrants must be operational in at least every story that is covered by a roof or the floor above, except the top two stories when the building reaches an effective height of 12 metres under construction. When we measure effective height, we measure from the lower story calculated in the riser stories. So there's a couple of definitions here that we need to understand. The first is the definition of a story. This definition describes what a story is and it doesn't matter if it's above or below ground, if it's got a floor and a ceiling or a floor above it, then it's a story and therefore it is subject to the E1.9. So the basement requires hydrant protection during construction once the effective height hits 12 metres. Pretty clear, so why the confusion? Well quite likely it's confused with the meaning of rise in stories, which is a calculation found in C1.2. And this is only about stories above ground, but as we just saw E1.9 applies to all stories as defined. It could be a confusion with effective height, which is only about the stories above ground, but as we just saw E1.9 applies to all stories. So with the exception of the top two floors, these are the locations of required hydrants in a building during its construction once it's reached 12 metres in effective height.