New shop AC now running, but..

[Codyboy]

Finally got a reply from the duct manufacturer.
They are not HVAC duct designers but just build to the customers specifications.
After doing some rethinking , I think (dangerous i know) that I only want 1000 to 1200 cfm on the main duct running the shop length. The other 400 cfm I would branch off the AH left and right at around 200 cfm each side. That would get me some air under the loft area that will be built later.
They recommend a 16" duct with two rows of 3" holes every 24 ". So for 50ft that would give me 48 or 50 , 3" holes. If I did the mathe correctly that would be a total of around 353 sq in.
The 16" duct would be around 200 sq in.
He said by doing it as described above would give some velocity out of the holes.
I suppose that means more forceful air coming from the holes?
Does this sound like a good plan?

He miss figured the hole size.

He revised the hole size to 2.25" at 24" o.c. which will give me 48 holes. At close to 4 square in. per hole will be a total of 192 square in. .
The 16" duct is 201 square in. on it's cross section.

So he's thinking being less outlet than input will give some force/velocity from the holes.

Just thinking in layman's terms, it makes sense now. I visualize it as putting your thumb over the end of the water hose to provide a little back pressure and get it to shoot farther out.

Any thoughts on this?
Thanks

 

[danski0224]

The design is worth what you paid for it.

 

[Codyboy]

The design is worth what you paid for it.

Thanks for the insightful help.

A lot of us DIYers are not made of money and trying to do what's right / effective.
I thought that is what this type of forum is about.
Helping.

 

[danski0224]

Thanks for the insightful help.

You're welcome. /s

A lot of us DIYers are not made of money and trying to do what's right / effective.

And it is also fair to say that someone putting up a 60 x 40 x 16 building has some money.

I thought that is what this type of forum is about.
Helping.

And there is a lot of erroneous information that is tossed around in this forum.

And there are times when correct information is provided, and something less is chosen.

If you want to do it yourself, and source your supplier yourself, then at some point, it may be in your best interest to follow the info that your supplier is providing. Or, find another supplier that will do your design work as part of the project cost.

If you don't trust the supplier, or whatever stuff you are reading, then getting some actual professional design work may be worthwhile- and this approach is NOT limited to HVAC.

 

[Codyboy]

You're welcome. /s

And it is also fair to say that someone putting up a 60 x 40 x 16 building has some money.

And there is a lot of erroneous information that is tossed around in this forum.

And there are times when correct information is provided, and something less is chosen.

If you want to do it yourself, and source your supplier yourself, then at some point, it may be in your best interest to follow the info that your supplier is providing. Or, find another supplier that will do your design work as part of the project cost.

If you don't trust the supplier, or whatever stuff you are reading, then getting some actual professional design work may be worthwhile- and this approach is NOT limited to HVAC.

Seriously? Fair to say someone that puts up a building has some money?

You know nothing about me but yet you talk like you know me and my situation.
Some, like me want things and have to do for themselves to get those things.
If I had money to throw at it don't you think I would? I mean being as I have money and all.

I come here looking for knowledge and inspiration to be able to do the things I'd like to do.
Then comes dan to throw in his 2 cents .

You sound like a troll. Pretty easy to search you and see thats true.

As far as trusting the supplier, there are thousands of threads on GJ that want some clarification to what a supplier, contractor is purposing.
My thread is no different.

 

[American Locomotive]

The thing to keep in mind that flow through a duct is not the same as flow through a hole. The flow through anything is a function of its diameter, length and the pressure. There are fans that can push 200 CFM through a 4" hole.

A duct manufacturer that doesn't typically do engineering will probably have some insights based on what they see customers spec out, or some basic rule-of-thumb.

It will probably work fine