Allowed to Mix Extended & Standard Coverage?

2/23/2022

We are working on a project where the Architect is very particular about the placement of ceiling components, including sprinkler heads. The idea is to line up diffusers, lights, sprinkler heads, smoke detectors etc. The problem is, in several locations, their preferred location will place heads more than 15 feet apart. The obvious solution for him is to require the heads more than 15 feet apart to be extended coverage type.

From a practical standpoint, it doesn't make sense to scatter extended coverage heads throughout the project as it becomes an installation and maintenance (heads that down the road needing replacement may be replaced with standard coverage by mistake) nightmare.

Is there anything in the code preventing the installation of extended coverage and standard coverage heads of the same style (i.e. concealer style) in the same area?

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11 Comments

Wayne Ammons

2/23/2022 06:48:09 am

You can mix standard spray sprinklers and extended coverage spray sprinklers within the same compartment as long as they are the same response and the spacing requirements for each type of sprinkler is maintained. If your standard spray sprinklers are quick response, your extended coverage spray sprinklers will need to be listed as quick response as well.

Alex

2/23/2022 07:09:22 am

HI,

I cannot think of a code section that states you cannot mix standard and extended coverage sprinklers. There should be some plan set forth though to prevent sprinklers from being replaced with standard coverage down the road.

The only code section that comes to mind is NFPA 13 (2013) 8.3.3.2 which states if quick response sprinklers are used, all sprinklers shall be quick response.

Thanks,
Alex

Anthony

2/23/2022 07:39:06 am

I'd suggest using concealed type sprinklers the cover plates look the same on each.

Jesse

2/23/2022 08:09:25 am

Yep, as long as the response is the same.

And watch your calcs if this becocmes the hydraulic remote area. Obviously, sprinkler coverage area is critical to the calcs, but the listing of the extended coverage sprinkler will dictate the flow / pressure that the sprinkler needs to calculate at.

Glenn Berger

2/23/2022 08:11:18 am

Mixing standard (coverage) pendent and extended coverage pendent in the same ceiling plane is a bad idea. I would ensure that the requirements for extended coverage sprinklers are met and use these throughout the given space.

Mike

2/23/2022 08:11:28 am

I thought mixing heads of different orifices within the same compartment was not permitted. Can't remember the section.

Cliff Schulze

2/23/2022 08:45:16 am

The code prohibits using different orifice sizes to minimize sprinkler discharge (NFPA 13 -2013 23.4.4.8.2). Obviously you can mix orifice sizes in situations like hotel rooms where you have an extended coverage sidewall protecting the sleeping area and a standard coverage head in the entry way.

2/23/2022 09:39:42 am

You're correct.

2/23/2022 08:46:23 am

This is allowed per the standard. Be careful of a few items:

1. Calculation methods, area reductions should still follow rules for NFPA and EC sprinkler manufacturer requirements.
2. Be careful spacing regarding sprinklers. Remember many EC sprinkler require a 8' minimum to prevent cold soldering vs 6' for standard coverage.
3. Pay attention to obstruction rules as outlined in NFPA as both will be different for each type for the same type of architectural feature.
4. Ensure response type matches.
5. A practice I like to do is making the EC sprinklers a different orifice if possible. I.E. make all EC sprinklers 8.0K and Standard sprinklers 5.6K ...this helps any field installation errors, this not only requires a different symbol on the print but also a different reducer size on the drop. **This may not always be cost effective!**
6. Make sure you can utilize the same manufacturer that will be listed in both OH and LH occupancies for the style of head you are using. For example: Your building more than likely will have LH & OH rooms. You are trying to use concealed sprinklers. Find a manufacturer that has both EC and Standard coverage sprinklers that are listed as QR for both style of occupancies in concealed style. Don't mix manufacturers if you don't have to.

Just my two pennies. Hope that helps.

Fred Walker

2/23/2022 09:26:57 am

Remember our job as FPE is to ensure proper fire and life safety, not to drive the Arch decisions. We have a tool bag that allows us choices which permit us to achieve our goals and permit the Arch to achieve their design intent and goals, giving the customer a safe and Arch pleasing environment.

We should not impose artificial constraints for our design simplification or maintainers connivence.

That said we do still have to address those technical design issues already identified in the comments previously.

Dave

2/23/2022 10:39:47 am

CJ covered the considerations that come to my mind, and I frequently (but not every time) mix standard coverage and EC. I often have a room (classroom for example) where four EC sprinklers make more sense than none standard coverage sprinklers, but perhaps there is an additional nook or door alcove that needs an additional sprinkler, and I might use a standard coverage sprinkler for that small area. Or in a corridor where corridor sprinklers give me the flexibility to spread them out but I need sprinklers for pockets that have significant shadowing.

Allowed to Mix Extended & Standard Coverage?

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