Detail Pick-Apart: Dry Sidewall at a Deck

11/1/2023

I'm going to go out on a limb here and do something I'm a bit apprehensive about as an engineer.

#1 FLAWS IN THE ARMOR
First - my number one fear of writing when I first started was that I was going to be wrong, and I was going to expose it for the world to see.

After all - Engineers are never allowed to be wrong. And when we are, we're not allowed to openly admit it, right!? Anyone?

Ok now that I've offended my friends, I should say that I'm flawed. I don't mean that facetiously. I've mostly gotten over the fact that I don't know everything; I have gaps in my knowledge. And even the things I do feel pretty adamant about, I'm still learning ways in which even those areas need improvement. I'm learning all the time.

So acknowledging first that I am flawed and make mistakes is piece number one.

#2 OPEN DISCORD
Second - it's better for the world to bring discussions out into the open - where we can all learn from it.

That's the entire point of the Forum, the point of writing as part of this blog, the point of MeyerFire altogether. What conversations can we start that everyone benefits from?

In that line of logic, today I'm posting this detail that is a sketch I put together for open critique. Hopefully, if this is something we all learn a little from and gain some useful knowledge, maybe it's something we can do again with different situations.

#3 IDEAS FOR CRITIQUE
Before we fire away, remember that any detail is simply an approach, a concept. It's one possible solution. It's not a cure-all for every situation. It's simply one approach of many.

I'd like to propose a few prompts to help the discussion related to this specific approach:

USE CASES: What are good use cases for this?
PROS: What benefits does an approach like this bring?
CONS: What are the negatives with an approach like this?
IMPROVE: What ways can this approach be improved?

Here's the concept:

So - what critique would you offer here?

What are good and bad use cases? Pros and cons with the approach? How could it be improved?

Thanks, as always, for being a part of making the industry better.

Anthony

11/1/2023 10:50:42 am

Quick notes:

Do you need a sealant other than the boot?
Define the minimum required length of "exposed barrel length" (conductive freezing concern?)
Is there a requirement for a hanger on the barrel if its over 1'-0?

Looks great otherwise!

Eric R

11/1/2023 11:33:14 am

This is a fun forum topic!

I think a good note on any dry head detail is to comment that the manufacturer's data sheet should also be reviewed. A perhaps simple way of sneaking this in would be to revise the barrel length note to say "exposed barrel length per MFG datasheet".

Also, speaking of data sheets, a quick check found at least one MFG that prohibits the use of a coupling as the connection fitting. I think having the note simply require the use of a tee and plug would be best.

I would like to know if using a boot is common approach for dry-heads not being installed in walk-in freezers. Personally we use rockwool insulation around dry heads we install.

Not necessarily something that should go on the detail, but if the inside portion of the dry head will be buried above a ceiling or soffit then the installer should try to insure that the head can be removed from the outside if possible. Since dry heads require sample testing relatively frequently, having a boot (or split ring hanger) on the inside wall that would require opening up the ceiling can add unnecessary future costs.

Jeffery McBride

11/1/2023 12:47:59 pm

The biggest concern I always have with these is that the minimum dry barrel length has to meet environmental conditions. The colder the outside winter averages, the longer the barrel. For example, a 6-inch dry-barrel in Montana may be an issue... Virginia, probably OK.

Also, I generally provide a note about effective sealing at the outside wall penetration. Even a small air gap can just about negate the effectiveness of the entire concept.

The space above the ceiling or in the bulkhead as shown is not really a heated area, per se.

Lastly, dry-type heads have to be replaced or tested every 10-years per NFPA 25, so we want to make sure that the installation provides reasonable clearances to remove and reinstall a new head if needed. That may actually necessitate accessing the T fitting from below...

Dave

11/1/2023 01:20:00 pm

By now others have covered the items I thought of when I first read it this morning, like sealing the outside, does anyone really use a boot here, barrel length, ease of removal later, hanger support, they can bottom-out in couplings… what’s left…“Sometimes I'll start a sentence and I don't even know where it's going. I just hope I find it along the way." While the architect may not like it, I’ll say this is much better than stuffing the pipe and tee behind a wall and squishing the insulation! But watch if the soffit you create makes you change how you sprinkler the room. A couple more related things, is the deflector parallel to the ceiling where required, and remember sidewalls can only be installed under smooth, horizontal or smooth flat ceilings (both often ignored).

Sean A. link

11/1/2023 01:57:42 pm

Hi Joe,

First very nice detail.

You could possibly add a note on the minimum dry barrel length & cross ref. to the pertinent section of NFPA 13 (2019ed would be 15.3 & Tables 15.3.1(a) & (b). "Sprinkler dry barrel length to be in accordance with chapter 15.3 of NFPA 13"

Sean A.

Casey Milhorn

11/1/2023 02:25:31 pm

Everyone covered it pretty well on the actual detail. I will be the negative one here and say most installations like this are a thing of the past. Victaulic's dry flex, though expensive, is almost always more economical than building a soffit. (somehow they knew to price it about 25% below the soffit cost.... lol. Almost like they planned it). From the grapevine, it sounds like at least one other manufacturer is working on a similar solution. Prices should drop when this happens. Also, not to mention architects/developers HATE these soffits/bump outs in their apartment units. Also, a dry flex pendent adds a nice option when you might have obstructions or other issues using dry flex sidewalls (for example in an "L" shaped balcony where sidewalls won't cover). Sorry, I know that wasn't the question but thought it might be helpful.

11/2/2023 09:26:34 am

We've been installing the VS1 dry flexes quite a bit lately, but are limiting our use of them to areas that are accessible like in full height attics or above suspended ceilings.

While they are an awesome product, the design basically doubles down on my above issue about endeavoring to install dry heads so they can be removed for testing without opening walls. With a VS1 sidewall, not only will you need to open the ceiling to get to the adapter fitting, but will also need to open the wall and try to snake the flex tube back out somehow.

And while I know that the sample testing frequency in NFPA25 has been increased twice recently, this is a whole new product type and I could see NFPA25 carving out a new test frequency specifically for them if there are any hints of issues over the next decade of use.

Anywho, I'm pretty far off topic about the detail, sorry for the derail Joe!

Pete H

11/2/2023 08:23:26 am

If using a dry flex pendent or sidewall, such as the vicflex, I throw on an extra detail on the drawing reminding folks that the vicflex can't go up. From the tee to the outlet it has to be a continuous downward angle.

You can pretty much rip what to draw from the detail out of the Do's and Dont's section of the catalog cut.

11/3/2023 04:19:06 pm

Once again since I last logged-on everyone picked up on anything I was going to add, but yes, it's easy to overlook that the Victaulic flexible dry sprinkler must slope down to the weep-hole at the end. However I had a project where the flex had to go up, THEN go down to the sprinkler, and I was told if the up-part was completely in the warm area, then it is okay. Don't quote me though.

11/3/2023 04:21:00 pm

Oh and about the threaded tee, it can go in either orientation, if it matters.

11/6/2023 02:34:37 pm

You're correct, it can go up in a heated area, but must be on a completely downward slope in the unheated area.

11/6/2023 02:42:14 pm

At least I think you're correct. Cause the whole point is no having any water that could freeze in a trappable location.

But yeah, gonna join the "don't quote me" club on this.

Joe Meyer

11/2/2023 09:32:13 am

These are all EXCELLENT comments - wonderful input. In a positive way, I think there's 8-10 more details or variations that could be built just out of this conversation.

I would think the next one to try would be the dry VicFlex option, and detail that with different nuances. Would make for a good comparison as I'd work on the different variations and improvements for this one.

This has been such a positive and helpful learning exercise, and I very much appreciate the input!! We're going to be able to create really helpful and really neat outcomes from these conversations.

Comments are closed.

Detail Pick-Apart: Dry Sidewall at a Deck

ALL-ACCESS

SUBSCRIBE

AUTHOR

FILTERS

ARCHIVES