Mix Standard Response with Fast-Response?

2/27/2024

NFPA 13 (2019) Section 9.4.3.2 states that quick-response sprinklers shall not be mixed with any standard-response within a compartment unless some conditions apply.

Section 9.4.3.2 Where quick-response sprinklers are installed, all sprinklers within a compartment shall be quick-response unless otherwise permitted in 9.4.3.3, 9.4.3.4, or 9.4.3.5.

If a quick-response sprinkler is a type of fast-response sprinkler, then not all fast-response sprinklers are quick response.

So my question is: can I mix standard-response with fast-response heads?

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9 Comments

Pete H

2/27/2024 06:38:56 am

Depends if the fast response sprinkler is listed as quick response or not.

For example, a reliable F1FR is a fast response sprinkler, but it is listed as quick response as it has a thermal element with an RTI of 50 (meter-seconds)^(1/2) or less and is listed as a quick-response sprinkler for its intended use (the definition of quick response as per NFPA 13, 2016 edition, 3.6.4.7).

But then there are extended coverage sprinklers that have fast response elements that are listed for standard response at extended coverage. For example the Reliable J112 is listed as quick response for light hazard, but in ordinary hazard it is quick response for 14 x 14 spacing and standard response for spacings up to 20 foot.

Basically, see what the listing of the sprinkler head on the catalog cut says.

Dan Wilder

2/27/2024 07:04:19 am

Yes, but only if you meet one of the exception criteria. A good example would be an overhead system with standard response sprinklers and in-racks utilizing fast response (Section 25.1.6.3 & 25.6.2.2 for example)

The intent of 9.4.3.2 is to keep the RTI similar between sprinklers, in this case less than 50 as the defined upper limit per NFPA. This is to prevent things like sprinklers outside area of the fire from activating (skipping) or more sprinklers than necessary activating (leading to more open sprinklers overall, potentially over-taxing the water supply)

While residential, quick response, and fast response all have different RTI's, they all fall under the 50 threshold and are allowed to in the same compartment (solely based on their response element, other factors may prevent mixing such as approvals, listings, and of course NFPA). There is a notable section 12.1.4 that requires all sprinklers installed within a compartment to be residential, however that is more addressing the spray patterns of the sprinklers than the response time.

Good breakdown below:

https://cdn.viking-emea.com/document_files/Automatic20Sprinkler20Thermal20Sensitivity.pdf

The JOB site (maker of the thermo bulbs)

https://www.job-group.com/produkte/job-thermo-bulbs/

https://www.job-group.com/en/products/job-thermo-bulbs/ (English chart)

Anthony

2/27/2024 08:15:22 am

What does mixing mean in this instant? can one portion of a warehouse be ESFR and one be OH2, sure.

Can you go every other sprinkler on a line a different sprinkler head type, NO. Each hazard should have its own design and consistent head type.

If it's a sprinkler replacement job for a single (few) then just match what is there now.

Glenn Berger

2/27/2024 08:23:42 am

IMO, It is not proper to mix sprinkler types (response or orifice types) within a "compartment." Unless you want to provide the building owner with zero flexibility to adapt the compartment to meet the Owner needs.

The majority of clients will not fix their sprinkler systems unless they get caught.

Jeremy S

2/27/2024 11:01:14 am

I have a situation where a warehouse has an existing ESFR system. The tenant is splitting the building and adding a Riser Room to separate the space. This riser room has caused the ESFR heads to be over spaced from the new wall. There isn't enough room to properly space ESFR head to this wall.

because the area needing new spacing has a door, it is designated as non-storage and can have a standard 8k head.

Does this area get standard response heads or quick response as the ESFR heads are "Fast Response."

Glenn Berger

2/28/2024 08:19:05 am

Where walls are modified, the sprinkler system on both sides of the new construction needs to be evaluated. The storage side would need ESFR sprinklers and the Riser Room being in a separate compartment it can have stand response standard sprinklers.

Jesse

2/27/2024 02:19:40 pm

Yes and no.

You can have areas with a warehouse that are ESFR (fast) and OH2 (standard). You can't intermix different responses on the same BLs for example.

Franck

2/27/2024 03:03:20 pm

NFPA 13 is very clear on that specific topic.

Sprinklers with different coverage types, K-factors, orientations, RTI ratings, and/or temperature ratings should not be mixed within the same area.

There are anyway some possible exceptions where the situation can be considered acceptable.

For example, ceiling-level pendent and upright sprinklers can be installed in the same area if they are used to protect two adjacent occupancy hazards that require different sprinkler designs.

An upright sprinkler can be substituted for an obstructed pendent sprinkler if:
• The upright sprinkler has the same attributes as the pendent sprinkler (other than orientation), and
• The upright sprinkler is an acceptable option to protect the occupancy hazard.
The same applies to substitute an upright sprinkler with a pendent sprinkler.

Ceiling-level sprinklers with the same K-factor, orientation, RTI rating, and coverage type attributes, but with different nominal temperature ratings can be installed in the same area if isolated ambient temperature conditions (such as near unit heater outlets) require a higher sprinkler temperature rating.

Standard sprinklers and quick response sprinklers should not be mixed in the same compartment.
Where quick response sprinklers are installed, all the sprinklers within the same compartment should be quick response.
The only exception is to provide quick response sprinklers inside rack storage arrangement with standard sprinklers at the ceiling level.

As a general rule, quick response sprinklers operate significantly faster than standard response sprinklers under the same conditions.
If sprinklers with different RTI are randomly installed throughout a compartment, sprinklers remote from the fire my operate prior to sprinklers in the immediate vicinity of the fire. This phenomenon is referred to as skipping, which can be detrimental to system performance.

Ceiling level sprinklers with different RTI ratings can be installed in the same area if:
A minimum 0.6 m (2 ft) deep solid noncombustible draft curtain is installed to separate the area protected by quick-response sprinklers from the area protected by standard-response sprinklers, and
A minimum 2.3 m (7-1/2 ft) wide space, measured away from the draft curtain, clear of combustibles is provided on the side of the draft curtain protected by standard-response sprinklers.

Ceiling level sprinklers with different RTI ratings can be installed in the same area if:
There is a minimum 0.6 m (2 ft) elevation difference between adjacent ceilings, and
Standard-response sprinklers are installed beneath the higher elevated ceiling, and
A minimum 2.3 m (7-1/2 ft) wide space, measured away from the elevation difference, clear of combustibles is provided on the side protected by standard-response sprinklers.

Now, there is the situation mentioned by Jeremy where you may need to mix ESFR with standard spray sprinklers.
It is normally not a good idea, as they have different K-factor, different RTI, possibly different orientation and different temperature ratings.
So, if you have an area protected by ESFR, adjacent to an area protected by standard spray sprinklers, these 2 areas should either be physically separated (by a wall) or the areas should be separated by a draft curtain or barrier located above an aisle, horizontally at a minimum distance of 600 mm (2 ft) from the adjacent hazard on each side.
The minimum height of the draft curtain should be at least 600 mm (2 ft).
Note that there is no specific requirement for the fire rating of the draft curtain. It should only be capable of stopping the heat from the higher hazard area from opening sprinkler heads in the lower hazard area.

But in no way you can have standard spray sprinklers (designed on the control mode, i.e. with an expected large area of operation) mixed with ESFR (designed on the extinguishing mode with a limited niumber of operating sprinklers - generally 12) in the same area.
A fire in the "standard spray area" may operate ESFR before the standard spray and then compromise the overall control of the fire.

Rob B

2/28/2024 07:37:50 am

This is spot on

Mix Standard Response with Fast-Response?

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