Author Topic: SMACNA Two Blade Dampers - What CID  (Read 286 times)

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Offline ScottieMTopic starter

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SMACNA Two Blade Dampers - What CID
« on: May 11, 2019, 02:46:03 PM »
Greetings,
I've always had it drilled into me that any dampers over 12X48 needed to be multi-blade dampers, and were ordered items. Recently, after looking at the SMACNA standard, that's not entirely true. Yes, it's multi-blade, but two single blades could be used in leu of a purchased multi-blade damper.
Looking to build one for our library, I cannot figure out how to get two dampers on one item for a "Two Blade Volume Damper."
I can add a D2 damper and get it on the same plain, but it wants to cut it as per C2 opening size, and I can't figure out how to separate them. Any Idea's?
Scott M.
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Offline DotNet

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Re: SMACNA Two Blade Dampers - What CID
« Reply #1 on: May 11, 2019, 03:34:31 PM »
I didn't know you could use 2 blades in leu of OBDs. It's not possible to place two on one end for the CID built in dampers though. Theyre tied to connectors (size/location). Might create one, set machine cut to "no", then name it appropriately so the shop knows what to build.

Offline ScottieMTopic starter

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Re: SMACNA Two Blade Dampers - What CID
« Reply #2 on: May 11, 2019, 04:31:05 PM »
Okay, I think I got something.
I added holes with calc's for where the damper rods would need to go.
Kept the single blade damper, but turned off the pierce points.
So..., it will make the tap with the holes and a single damper for the overall size, but the guy's will have to split the damper on the shear to make two dampers.
Add hardware and done.
Scott M.
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Offline Rick Hillson

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Re: SMACNA Two Blade Dampers - What CID
« Reply #3 on: May 15, 2019, 10:11:13 AM »
CID#921  has a max dim "E" which you can set to what you need and it will give you two blades.
Not sure if it will burn the two holes required.

Offline ScottieMTopic starter

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Re: SMACNA Two Blade Dampers - What CID
« Reply #4 on: May 15, 2019, 10:08:21 PM »
I'll have to take a look. Everything is closed for the day.
This is what it looks like finished.
Scott M.
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Offline cadbob

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Re: SMACNA Two Blade Dampers - What CID
« Reply #5 on: May 16, 2019, 09:58:36 AM »
Looks great, nice work, but with adding up the time and labor, would not a store bought multiblade be easier and cheaper?
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Offline ScottieMTopic starter

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Re: SMACNA Two Blade Dampers - What CID
« Reply #6 on: May 16, 2019, 12:28:24 PM »
We kinda looked at that. A 16x16 bought was $55.
The adders were: labor cutting the damper in half and forming, hardware and attaching, and install time for an dditional damper.
It was slightly better than a wash, but larger dampers and associated cost, and lead time are the other factors that made this make more sense.
So, we can go to 24x48 before having to purchase, and it is only for reduced volume damper where the dampers are going to be open, generally.
The fitting was able to download, have the holes, and the damper piece was cut, same as a single.
Scott M.
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