Commercial Steam Shower Requirements - Perm Ratings
So I understand that there is new requirements in place (or soon coming into place) for commercial steam showers. The Perm Ratings requirements I believe need to be 0.50.
I'm not sure what manufactures other than Noble Company are going to make this new requirement. The Noble membrane is rated 0.05 for the Noble Seal TS material but the KErdi membrane from Schluter has a perm rating of 0.75 I think.
It might be that Kerdi over concrete board is no longer an approved method for commercial steam showers.
I will send out a note to my Schluter rep looking for clarification. I think that Kerdi Board might pass this new requirement.
I will also touch base with Wedi and Laticrete to find out if their products will make this new requirement.
Stand by for up dates.
JW
Continuous Use Steam Rooms - Kerdi Process (Kerdi DS)
I heard back from Bob Weins yesterday and he granted me permission to share this information online.
Here is Bob's email to me.
Hi John
As mentioned there are changes in regards to acceptable levels of vapor transmission for 2013. This is a combination of information revision from our 2013 Handbook / Technical Data Sheets.
Water exists as both liquid and vapor in showers, and needs to be managed in both forms. Steam showers not designed to manage water vapor have caused mold growth, rot in wood framing, and damage to moisture-sensitive wall coverings on the opposite side of the stud cavities.
The ANSI A118.10 standard for bonded waterproof membranes was developed to provide a framework for determining the suitability of these products to serve as barriers to positive liquid water migration only. The standard does not include a minimum criterion to establish the ability of products to limit vapor transmission therefore selecting a membrane that only meets the requirements of the ANSI A118.10 standard for a steam shower application is not enough. The ability of the product to limit vapor transmission must be considered as well.
Water vapor permeance is a measure of how quickly water vapor is transmitted through a material and can be determined according to the ASTM E96 Standard Test Method for Water Vapor Transmission of Materials. The higher the vapor permeance, the less effective a material is at slowing vapor transmission.
There is no universal requirement for vapor permeance of membranes in the building industry. The environmental conditions (i.e., differences in temperature and relative humidity), building materials, etc., and relevant field experience will determine the appropriate membrane performance for a given application. The consensus within the tile industry in North America has been that a vapor permeance of 1.0 perm or less will manage vapor effectively in showers and steam shower applications.
Recent developments in the industry indicate that a more conservative recommendation will be implemented in the TCNA Handbook for Ceramic, Glass, and Stone Tile Installation and the TTMAC Specification Guide 09 30 00 Tile Installation Manual for continuous use steam rooms as follows: Membranes for continuous use steam rooms (e.g., those found in health clubs, spas, etc.) should have a water vapor permeance of 0.5 perms or less when tested using the desiccant method at 100°F (38°C) and 90% RH.
TILE INSTALLED IN STEAM ROOMS
321SR-2012-2014
"For continuous steam rooms if the waterproof membrane is acting as both the waterproofing membrane and the vapor retarder the waterproof membrane must have a perm rating of .5 or less using ASTM E-96 Procedure E with 90 % humidity. If the waterproof membrane has a perm rating higher then .5 then a vapor retarder
should be used that has a perm rating 1.0 or less when tested with ASTM E-96. This is to be located behind the solid backing such as a cementitious backer board."
Schluter®-Systems has tested the various options within the Schluter®-Shower System for moisture management, including Schluter®-KERDI, Schluter®-KERDI-DS, and Schluter®-KERDI-BOARD in the more aggressive conditions referenced above. The table below summarizes Schluter®-Systems recommendations for the use of these products and respective water vapor permeance values.
Product Recommended Applications Water Vapor Permeance (perms)1
KERDI-BOARD Showers, intermittent use steam showers, and bathtub surrounds 0.362
KERDI Showers, intermittent use steam showers, and bathtub surrounds 0.903
KERDI-DS Continuous use steam rooms 0.19
1Tested according to ASTM E96, using the desiccant method at 100°F (38°C) and 90% RH
21/2" – 12.5 mm -thick KERDI-BOARD tested
3Previously reported a value of 0.75 perms when tested at 73.4°F (23°C) and 50% RH
While the water vapor permeance of Schluter®-KERDI-BOARD meets the new recommendations for continuous use steam rooms in upcoming tile industry standard guidelines, Schluter®-Systems has chosen to require the KERDI-DS membrane for these demanding applications in an effort to be conservative and provide the best possible solution for our customers.
Thus, the Schluter®-Shower System has solutions that provide superior moisture management for virtually any tile application.
Continuous Use Steam Rooms – Ceramic, porcelain, and natural stone tile
Schluter®-KERDI-DS waterproofing membrane
This drawing will be modified to look like a more
traditional steam room with a bench and generator outlets.
Kerdi DS is now available in Canada. I ordered my roll from Ames Bros here in Burnaby, B.C. I would imagine any Schluter retailer can bring it in for you.
This is a big moment for me. Those of you that have followed my posts for a long time Know I have always had issues with the fact that Kerdi is installed differently in Europe as it is in Canada. I learned much of my skill set from my UK peers and finally have a system that meets my standards and is available in Canada.
I'll post a few pictures once I get the roll of Kerdi DS.
I'll double check with the Noble Boys on their commercial steam shower spec but assume they have already being meeting this new standard for years.
JW
