Hi Everyone. I am looking for a manufacturer that can achieve STC55 on a 1-3/4" thick steel door. I have flush and vision type elevations. So far I was able to find one manufacturer and they are asking for almost $20k per door. Please let me know if yo u have heard of anyone. Thanks.
Doors are 3x7.
Krieger makes excellent sound control doors
thanks Nathan. I am a customer of Krieger and I know Bob McCluney however their STC55 doors are 3" thick.
I don’t think you will easily be able to achieve this with a 1-3/4 inch door. The cost you cite does not surprise me. An alternate solution may be to use communicating doors (two doors into a single opening) each with an appropriate STC rating (determined by the acoustical engineer or door manufacturer). That may be cheaper. In some projects I did, I raised these concerns with the acoustical engineer and asked them to reexamine the conditions and confirm that the high rating is needed. Many times the answer was no, and a door with a lower rating was fine. Personally, I don’t think it’s a good design approach to depend on high STC ratings for a door. They are expensive, may be hard to operate due to weight and hardware, and can get out of adjustment negating the rating. I prefer to see physical separation in the form of another space between the two rooms that are to be separated. Of course, this is sometimes not workable.
I concur with John. Considering the practical limitations of squeezing STC 55 into a 1-3/4 inch deep opening can a 3 inch deep opening be considered? I presume your walls are sufficiently deep to accommodate a deeper opening if you’re trying to achieve an STC-55 in a gyp board assembly.
Tolga,
That is a very large STC value! Why do you need it to be so high?
Tolga,
There is no way that you are going to acheive that STC rating with a 1-3/4 inch thick steel door.
Krieger will get you up to STC 53 with a 1.75" door, but their STC 55 doors are 3" thick:
https://www.kriegerproducts.com/acoustical/models/
Gentlemen, thanks for your response. Here is the story behind. Job is for US Military overseas. I know it is crazy but these doors are for apartment entrances. We have been trying to educate eveyone involved (Contractor, QC at government, PD at government) that this requirement is out of the world and if there is an alarm, the soldiers might not even hear the sound but it is like talking to a wall. There is actually a manufacturer (I dont want to advertise them) that says they can achieve STC55 on a 1 3/4" thick door and provided me the reports on that but the cost they are asking is too much.
I have submitted Krieger STC53 as 1-3/4" and got rejected as they asked for STC55. I submitted Krieger STC55 2-3/4" and got rejected due to thickness. Turning in circles for the past 6 months.
Sad part is this is tax money getting out of everyone’s pockets for no reason at all.
Nathan,
Thank you for information on the Krieger product. I will be sure to file that away in the back of my brain if a higher STC door is required on one of my projects.
Tolga,
Please name the manufacturer and product. Maybe someone here has experience with that product.
Remember that you cannot just put a high STC sound door in a typical gypsum board wall. The wall has to be a special configuration. Check out Gypsum Association’s Fire Resistance and Sound Control Design Manual.
You could always write a performance specification and see what the contractor submits. 
All,
The independent door hardware consultant I work with does not want me to specify Norise Barriers QuietSwing doors. He says there are issues with the design of the door and mounting of door hardware.
One other caveat, of many, when using the Gypsum Association or other STC “rated” wall systems. The designs are almost always based on “25 gage” studs spaced at 24 inches OC. I don’t recall ever seeing a wall like that on a project, especially a government project.
Tolga, I am sorry that you are dealing with obtuse people who don’t understand construction or construction law. My guess is that you are dealing with a design calling for 30 to 33 mil studs spaced at 16 inches OC. Regardless, unless you’re planning on working with MarinoWare’s SoundGuard-https://www.marinoware.com/product-category/soundguard/ studs I don’t know if your assemblies have a chance of achieving STC 55 unless you’re using a double row of offset studs completely isolated from each other in which case your wall will be deep enough to easily accommodate a 3 inch door. Perhaps you can contest the Work as being sole-sourced and closed proprietary. Last I checked our military has self-imposed limitations on that sort of practice. Challenge them to provide three compliant products and manufacturers; otherwise it would appear that the project is not constructible as designed.
Good Morning Everyone,
Thanks for the supportive arguments. I will let you know about the progress, next meeting is after holidays.
Please see link below for the data sheet for the STC56 1-3/4" doors.
https://arcacoustics.com/wp-content/uploads/2017/08/steel-door-brochure-2.pdf
This is an interesting product. I am wondering if you can get the flush door without a lite that has a UL fire rating
Wow! That product is amazing. If true I may have to take back my comments.
I have passed this information on to an acoustical engineering consultant for his input.
Thanks Tolga for bringing this to our attention.
It is interesting that this door can meet this rating, though I’d like to see the caveats, if any. Notably, though they show the door with a full vision lite, the graph with STC 56 appears to be for the flush condition, with the vision lite door it looks like less than 56. Tolga stated that there were some with vision lites. Eyeballing the sketch in the PDF, it looks like the door would be about 3 inches thick at the lite. So a bit awkward there. Do they have any fire-rating, which may be needed for an apartment door?