Backup Power for All Fire Pumps in Highrise?

5/12/2021

NFPA 20 5.6.2 requires a fully-independent and automatic back up pump for very tall buildings. This project is just under 50 stories with a pump and back up several levels below grade serving the lower zones and another pump and back up several levels above grade serving the remaining zones.

The project’s electrician cannot meet the power requirements for the worst case scenario, which would be all (4) pumps operating at once (if the primaries are running, but not at full capacity).

The request is to interlock the primary and back up on the respective level, so only one pump is running on the level at a time (for a max total of two pumps running in the whole building).

Would interlocking the pumps on their respective levels still satisfy the requirements of NFPA 20 5.6.2 (copied below)?

NFPA 20 5.6.2 Fire Pump Backup. Fire pumps serving zones that are partially or wholly beyond the pumping capability of the fire department apparatus shall be provided with one of the following:

A fully independent and automatic backup fire pump unit(s) arranged so that all zones can be maintained in full service with any one pump out of service.
An auxiliary means that is capable of providing the full fire protection demand and that is acceptable to the authority having jurisdiction.

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5 Comments

Todd E Wyatt

5/12/2021 08:59:05 am

I would recommend starting in the scoping Code (e.g. 2021 IBC) for the fire protection requirements for a "high-rise building" (HRB).

Section 403 identifies the special detailed requirements for HRBs. "403.3.4 Fire pump room" refers to Section 913.2.1. "403.4.8 Standby and emergency power" references "Electically powered fire pumps" which classifies them as "emergency power loads" in "403.8.4. Emergency power loads".

Section 913 Fire Pumps references NFPA 20 in 913.1 ("fire pumps ... shall be installed in accordance with this section and NFPA 20"), in 913.2 ("fire pump ... shall be protected in accordance with NFPA 20 against possible interuption of service through damage ..."), in 913.2.1 Ex 2 ("Separation is not required for fire pumps physically separated in accordance with NFPA 20"), and 913.5 ("Acceptance testing ... NFPA 20").

NFPA 20 (2019) is a "referenced standard" (See Chapter 35) by the 2021 IBC (See Chapter 35). NFPA 20 is only applicable per these (5) references. Unless the jurisdiction has adopted the NFPA 20, you only need to follow the referenced sections per the adopted (scoping) Code.

Jay

5/12/2021 04:25:55 pm

913.1 requires the fire pump to be installed in accordance NFPA 20. That means the entire standard and not only certain sections of NFPA 20, except where there are conflicts between NFPA 20 and the IBC/IFC, in which case the IBC/IFC governs.

James

5/12/2021 04:31:01 pm

Agreed; once a fire pump has been introduced I've always understood the whole standard of NFPA 20 to be applicable.

5/13/2021 08:40:25 am

Per the scoping Code (IBC), it states :

102.4 Referenced Codes and Standards
The codes and standards referenced in this code shall be considered to be part of the requirements of this code to the prescribed extent of each such reference and as further regulated in Sections 102.4.1 and 102.4.2.

102.4.1 Conflicts
Where conflicts occur between provisions of this code and referenced codes and standards, the provisions of this code shall apply.

102.4.2 Provisions in Referenced Codes and Standards
Where the extent of the reference to a referenced code or standard includes subject matter that is within the scope of this code or the International Codes listed in Section 101.4, the provisions of this code or the International Codes listed in Section 101.4, as applicable, shall take precedence over the provisions in the referenced code or standard.

5/13/2021 02:15:41 pm

913.1 prescribes the use of the entire referenced standard, NFPA 20, not only specific sections of NFPA 20.

Backup Power for All Fire Pumps in Highrise?

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