Letter # FLR-2THK-CONC
August 7, 2015
Floor fire barrier with 2" contact substrate
Spectrum Specialty Builders Attn: Dan Pridemore 3902 West Valley Hwy North, Suite 500 Auburn, WA 98001
Project: Lincoln Square II
C/S Project #: 156859
RE: Expansion Joint Fire Barrier Information Slab Thickness
Location: Bellvue, WA
Dan, On the above mentioned project it has come to our attention that due to construction conditions that it has become necessary to install the MFX floor fire barrier in a slab depth that is less than that shown in the products UL listing. Reference the attached example UIL listing FF-D-1066 and the 4 ½” deep slab indicated. The floor fire barrier in this case was tested on a 2 hour rated concrete floor slab which has a thickness of 4 ½”. Where is is necessary to install fire barrier in a condition where the slab thickness is less than this it is our recommendation that at a minimum 2” of contact of the fire barrier blanket material maintain contact with the concrete slab (see clouded dimension on the sketch attached). It is our opinion that as long as this is maintained that the fire barrier’s integrity will not be compromised and that it will perform up to the rating of the adjacent substrate. If you have any questions regarding the information herein or need anything additional please feel free to contact us. Sincerely, Construction Specialties Inc.
Kevin W. Smith, PE Engineering Manager Expansion Joint Cover Systems Encl cc: file, Pam Weihermuller (C/S)
6696 State Route 405 Muncy, PA 17756
Phone 570.546.5941 Fax 570.546.8022
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