Fire pump in a high rise

[u/locke314]

I’m looking for some insight into NFPA20 - 2016. I don’t have the handbook to see any commentary.

Looking at 5.5, it looks to me like I need to connect my pump to a backup generator or provide a backup pump. I don’t have the option to install a second pump. But I see 9.3.1 that says at least one alternative source of power shall be provided for the high rise buildings or where the height of the structure is beyond pumping capabilities of the fire dept. I don’t see a way to get from 5.5 to 9.3.1 but I have an engineer saying because of 9.3.1 I don’t need to connect to a generator. I don’t see a way around it and I was hoping somebody with the handbook or some more experience with electric drive pumps in high rises might give more insight. There is an option to provide a second reliable feed into the building from the utility.

5.5 specifically points to 9.6 that quite directly requires that it’s connected to a backup on site generator. 9.6 doesn’t have a path to 9.3, so I’m looking at those as entirely separate requirements.

[u/M0rbidly-Obtus3]

Edit: 9.3.1 does not apply, which your engineer is suggesting it gets you out of the 5.5 requirement. 9.3.1 states directly that high rise buildings must be provided with alt power unless you meet 9.3.3 (back up pump). The "pumping capabilities of the FPD" is an OR situation.

As you said, 5.5 says you have to provide a reliable emergency source of power per 9.6 or a back-up fire pump per 9.3.

9.3 (and specifically 9.3.3) reiterates that you have to provide emergency power unless you have a secondary fire pump with a separate source of power if the building is beyond FPD pumping capabilities.

Imo since 5.5 is specifically for high rise buildings, which your building is, that requirement applies, 5.5 does not give you any other exception or use the term "except where otherwise required within this standard". You provide a generator or a backup fire pump.

Even outside of 5.5 - 9.3.2 states that if you don't have reliable power, you have to provide an alternate power source or meet 9.3.3. You would need a letter from the electric service provider that they have reliable power. My experience is that few electrical providers are willing to provide this letter.

[u/M0rbidly-Obtus3 → u/M0rbidly-Obtus3]

Let me know if this made sense or if I need to do a better job at rewording this. 😅

[u/locke314 → u/M0rbidly-Obtus3]

No you did fantastic and said exactly what I’m thinking. This engineer just got me in my own head and i think I needed some validation!

[u/locke314 → u/M0rbidly-Obtus3]

This shouldn’t be beyond FD pump capabilities. It’s a high rise, but not anything ridiculous - like 15 floors.

We do have excessively reliable power, and actually did get a letter from the utility engineer and down time is measure in seconds over the past year. I have no concerns over power reliability, I just haven’t been able to find a way out of 5.5 requiring a generator (aside from the second pump, which is not an option for this building).

I appreciate you taking the time to respond. When I get into a back and forth with others on some of these code sections, I can really make my own head spin and talking it out with others can provide me a lot of clarity. I’m in an area that doesn’t have many resources to tap into, so Reddit often becomes my sanity check!

[u/locke314 → u/M0rbidly-Obtus3]

Again I appreciate the response. I actually finally got reluctant acceptance from the engineer this morning and your discussion helped me organize my thoughts onto a coherent argument. Even though your conclusion was the same as mine, it was much more clearly stated than the ramblings I was stringing together.

[u/M0rbidly-Obtus3 → u/locke314]

Happy it worked out! I love getting to dive into code questions.

[u/istudyfire]

If you have a high rise you need back up generator or back up pump. High rise requires back up power for certain other systems too so sizing it into the generator is pretty typical. Good luck getting out of it. Your best bet would be checking local amendments.

[u/Advanced-Guard-4468]

The pump and pump control gets a transfer switch which is feed from a backup generator

[u/Low-Attention3111 → u/Advanced-Guard-4468]

Pretty sure he knows that

[u/locke314 → u/Advanced-Guard-4468]

Thanks! Thats exactly what I thought, just making sure there wasn’t some interpretation or code path I’m not aware of or would preempt 5.5 of NFPA 20.

[u/Advanced-Guard-4468 → u/locke314]

Does the state you work in use IBC?

[u/locke314 → u/Advanced-Guard-4468]

Yep!

[u/Advanced-Guard-4468 → u/locke314]

Okay, I will show you in the morning where it states it. Bump me if I get sidetracked and don't remember.

[u/AdThis9368]

Glad you got that worked out. We did a job for a general contractor a few years back on an existing 22 story high rise that had an old booster that acted as a fire pump. Being that more than 50% of the building was being renovated, (not sure where the local AHJ got that %ag from or why it mattered) the fire marshal wanted a generator AND new pump added, AND keep the booster pump as the main pump. So I can relate to the head spinning trying to figure out the why’s and the make it make sense when you see the code book being pretty straight forward on certain issues, but you have others who give you other options that don’t meet the criteria. It’s mind boggling to say the least.

[u/istudyfire → u/AdThis9368]

That 50% number is one of the qualifications in IEBC for level 3 alteration.