Read this if You are Building in a Seismic Zone? Part 1 of 2

Are you building in a Seismic Zone?  If so, are you aware that there is a required clearance around your sprinkler pipes. If you do not meet this requirement, you are risking the life safety of your building. So, if you are in a seismic zone, please ensure your team conforms with this requirement.


Allow me to share a little story with you before we get into the specifics.


I was part of the quality control team on a massive construction project. I had written the build team up, because they did not conform with this particular clearance requirement we are discussing.  The executive team called me into a meeting to explain the information in the report.   I didn’t know everyone in the room, but of the executives I knew, I had tremendous respect for them. My goal has always been to be a catalyst for positive change and you can’t do that if you run around with a chip on your shoulder always having to prove you are right. My responsibility was to help make the building as fire safe as possible.


My report said that they didn’t have proper clearance around the sprinkler pipes. The sprinkler guy asked me what I was talking about. I confirmed that we were in a seismic zone and then mentioned that “I thought” the NFPA had requirements for clearance around pipes, but that the sprinkler guy works in the NFPA realm and I work in the IBC realm. So, I asked if he would do me a favor and check the NFPA and confirm whether or not I was right.


He agreed and what this man did next surprised me. It also made me glad I didn’t just tell him, “I’m right and you are wrong!”.


This guy found the code section I had referred to. He emailed it not only to me, but also to the entire team of executives who were at the table. He thanked me for bringing this to his attention and promised to rectify the issues I had brought to light.


The next time he saw me in the hall way, he stopped me and said, “Hey, in that last meeting…You knew what you were talking about and probably could have quoted the code section off the top of your head.  Am I right?“ I smiled and said “9.3.4? Yeah” As he walked away smiling, he just said “Thanks”.


I could have fought with him. Maybe I could have made him look bad, but instead I earned his respect and who knows the ripple impact that made.  My hope is, that he never forgot that codes section again and buildings he was involved with were safer because of it. So, the next time you know you are right, take power in that and don’t get defensive when people question you. Find a way to make a wave of positive change.



For those of you who don’t know NFPA 13, section 9.3.4, it basically says that, if you are in a seismic zone, all pipes through concrete or block walls and floors have to have a flexible coupling within 1 foot of each side of the floor or wall. There is an exception for “frangible substrates” (easily breakable) such as a gypsum wall IF it is not rated or IF you are using non-metallic pipes that have sufficient flexibility.  So, if you are making a hole in a rated wall or floor for a sprinkler pipe, please remember that without the seismic coupling, the hole needs to be sized:

2” larger than the outside diameter if your pipe is 1” to 3.5”

4” larger than the OD of the pipe if your pipe is 4” or larger


That means if you have an 8” diameter pipe, you have to have a 12” diameter hole.



If an inflexible pipe is going through concrete, the concern is that the seismic activity could potential cause the pipe to bash into the concrete floor or wall. This could easily result in one of two scenarios:

  1. the pipe breaks and can not supply water to the fire
  2. the rated concrete assembly breaks and can no longer preventive passage of smoke and fire



I hope this little tidbit can be useful to your next project if you are in a seismic area. If you are, I would suggest you read this section of the NFPA so you know the specifics; because this information is just a general overview and there is additional information in the code, above what I have noted here, that might be pertinent to your project.  But we have not even talked about firestop YET…


Our next post will explain a bit of a problem that you may encounter due to this requirement.  If you have any questions or if we can support your construction project, please reach out to us. Please share this with anyone who may benefit from this. Until then, keep learning and be safe!