What's your experience with Duct Sox? 2

[atlas06]

I have seen some duct sox in operation at the Gym for about two years now. I have an application for such a thing but I hesitate about the durability and maintenance of this material.
I've seen some with a type with linear slot of holes and a other totally perforrated types. I can see that it helps spread the airflow throughout the open space evenly without having the draft of a 4000 CFM round diffuser damping air into people's bold heads. Very light and easy to install material, and not so bad looking.

what's your experience with duct sox? what do your clients say about it?

 

[AbbyNormal]

I have been aware of them for quite a while now, I have them on paper only for two projects that have not been built yet.

Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[NCDesign]

I've used fabric duct on several projects, 2 gyms, a large industrial application, a large church sanctuary (4,000 plus seat sanctuary), and industrial style office space. When installed and balanced properly it is great. You get a very quite installation with good airflow and even temperatures. I am a big fan as it can give you some serious savings over painted spiral duct and give you better performance to boot. I would work closely with the product rep or better yet the factory to lay-out and size the fabric duct. They can really help you get the right fabric and distribution type for your application. Be sure that the system gets balanced properly. My biggest problems with fabric duct came with improperly balanced systems. When the systems where rebalanced correctly the problems went away. If you use it in an industrial application be aware of the dirt factor. My industrial application ran white fabric duct directly over the discharge of an electrical control cabinet. Needless to say they ended up getting dirt spots at that location. The good thing was that it was fairly easy to take the duct down wash it and hang it back up as good as new.

 

[NCDesign]

I also meant to add that all of my clients have been very, very happy with the fabric duct.

 

[CarolinaPE]

Works pretty well. We have a job where someone walked on it and left footprints before it got installed. Pretty funny to see when it is installed 20 plus feet off the ground.

 

[marcoh]

We've got a couple of projects which are about to be commissioned so good to hear they all work well. From my experience would the suppliers were very helpfull in achieving the right holes etc for the correct air distribution and they should be consulted from the very concept design stages.

 

[absrbrtek]

They work well as long as you have good filtering. I have seen them plug up internaly with lack of proper air handler mainanence. Then when the blower would start up the internal static pressure would blow the sock off. Other than that I have seen them around for about 12 years, all of the customers were pleased. JMHO

 

[vannic]

The only place I have seen that wasn't a good application was VAV systems. The VAV boxes were painted to match the sock but at low loads, there isn't enough air from the VAV box to keep the sock inflated. It looks kind of bad.

 

[atlas06]

Although I'd never consider a duct sox for something other that a Gym or wide open space using CV system, I must say Vannic that you make a good point to remind others not to use it for VAV system.

On a follow up:
How did you sell it to the architect and the owner? was it easy to sell or did they actually originate the duct sox application? and were there truely real costs savings compared to sheet metal?

 

[NCDesign]

The first time I used fabric duct was at the owners direction. I had my doubts because I was unfamiliar with it, but it was a great installation. I usually recommend it in any application that would typically be spiral duct with sidewall grilles, especially if it is going to be painted.

A couple of things that can be a big driver on costs are the type of fabric and the color chosen. If you stick with most manufacturers "standard" (i know there can be a lot of variation here) fabric and their standard colors you will see some significant savings. When you go to premium fabric or non-standard colors those installed savings start to diminish. Also, cost savings start to disappear with more complex lay-outs.

One other gotcha in regards to installed costs is whether or not the contractor is familiar with it. An unfamiliar contractor may figure it will take the same amount of time to install as spiral since they probably don't have any numbers to go by. It is a much, much faster install.

Finally, I have found it very easy to sell to both architects and owners. Owners like it because of the lowered install costs. Architects like it because it is very easy to work with and gives them a lot of options. As with most systems that we deal with the best way to sell it is to take the clients to another installation. Once they see it in action they are usually sold.

 

[vannic]

As an engineer working for a contractor, i can tell you that installing a duct sock system is not necessarily as easy as installing spiral duct. The reason being is exactly what NCDesign points out; it isn't used much at all. Repetition and familiarity only adds speed and expertise to even complicated systems. Duct sox definitely have a place in HVAC design from an engineering standpoint. Without a doubt the best applications are natatoriums where it is imperative to get even air distribution on glass to prevent fogging/condensation. Architects who fall in love with the flexibility of color and uniform shape usually drive the selections that I have been a part of.

 

[Fabricguy]

I have used Fabric ducts on quite a few jobs, and like eveyrone else I was quite apprehensive about them at first.
I have even used them on VAV jobs, the key is getting the fabric duct supplier involved early in the job and keeping the lines of communication open. VAV is possible with fabric but it must be pointed out in the design stage,(the ducts need to be designed at with at least .25" esp on the lowest setting to keep the duct fully inflated, this may raise the esp on the highest setting, just make sure the equipment can handle it.)

jobs I have used the fabric on :

Natatoiums (fully agree with vannic here)

gyms

warehouse

office space (halfround ducts work well and look decent also)

hockey arena

library (if balanced/designed right they are quiet)

One neat thing about them is the colors can be matched to school colors (although adds cost) and even mascots can be placed on the ducts. I had one school order several sections with company logos on them and the comapnies paid to have their section up fuctioning in the system but also advertising for their company. The school had their duct system paid for in 2 yrs!!

Be careful with high inlet velocity and turbulence at the inlets as this can make the duct visibly move or vibrate!! Most say 1400-1600fpm inlet velocity, be sure to have the manfuacture give you a layout with dimienision etc.

Duct sox is the big brand name out there but shop around as I have used a few different manufacturers and have had satifactory results (the danish companies seem to be the most experienced, as this product is claimed to have been produced there first) Just make sure the company has a UL listing and can provide written technical data, performance gaurantee, warranty, etc.

 

[OLYMPICMech]

How do you size up blower when installing duct sox???

Size, Length, CFM needed, etc. (static pressure)???

Any help???

 

[NCDesign]

http://www.ductsox.com/ductsoxweb/d...ign+Manual+Detail-Design+Manuals!OpenDocument

Better would be to go to

http://www.ductsox.com

and find your local rep.

 

[williamsGA]

We have Duct Sox in our office, and I have used them in a number of applications and am very please with them. In our office with have two different types, the liner slot and perforated holes. I don't think they make the liner slot anymore as it has a tendency to clog. I personally have taken down the ductwork and washed it once. The system has been installed for 5 years, after washing there have been no more problems with airflow. If an engineer can work out how to take the duct sox down and reinstall, it can't be all that hard.