Fire Rating Facts:
Fire Resistance:
All sizes of Premiere & ThinLine series Pittsburgh Corning Glass Block® products in panels up to 120 sq. ft.
in masonry walls or 94 sq. ft. in non-masonry walls are classified by Underwriters Laboratories® for use as
45-minuted-rated window assemblies. These panels are usually acceptable as window assembles for use in
fire separation walls requiring one hour or less.
Thickset® & Vistabrik® glass blocks are listed for use as 45- 60- or 90- minute fire rated window assemblies
in panels up to 100 square feet.
Refer to the latest issue of UL® Building Materials Directory as well as your local building codes.
- Underwriters Laboratory Classification: R2556
- Underwriters Laboratories of Canada File: CR 1715
- In accordance with NFPA 80, Chapter 14
Fire Rated Glass Block Window Assemblies:
Pittsburgh Corning Glass Block® products listed above have been tested and classified by Underwriters
Laboratories® (UL®) for use as fire rated window assemblies to panel sizes and dimension limitations listed
below.
Where permitted by Building Codes, glass block fire rated window assemblies having a fire resistance rating of not less than 45 minutes, may
be used as "opening protectives" and to not exceed 25% of the wall areas separating a tenancy from a corridor or a corridor from an
enclosed vertical opening or one fire-rated area from another fire-rated area.
Exception: Although glass block masonry units have been tested as window assemblies (not wall assemblies), they may be used as a one
hour fire partition as required for corridors in the enclosure of atriums only when sprinkler protection is provided on occupied sides.
45- & 60-Minuted Rated Construction:
All 45- & 60-minuted rated PC Glass Block products may be used in both masonry and non-masonry (steel or wood stud gypsum board) walls.
These rated glass block windows are framed and anchored with either PC® Panel Anchor construction or channel-type restraints. The use of a
fire retardant type sealant for head and jamb locations is required. Specification and construction details of such panels are per Pittsburgh
Corning Corporation recommendations.
Non-masonry, fire-rated steel stud/gypsum board walls must conform to UL® listed wall assembly #U465. Framing and support of the rated
glass block window assembly shall be provided with double-studding with height of supporting wall limited to no more than 3 feet.
90-Minute Rated Construction:
Where permitted by building codes, all 90-minute rated PC Glass Block® products may be used in masonry walls only, framed and anchored
with 1/4 in. thick steel (not aluminum) channel-type restraints or masonry chases. The use of panel anchor construction is not permitted.
Specifications and construction details of such panels are as per Pittsburgh Corning Corporation recommendations.
Exception:
In 90-minute rated glass block window assemblies twice the thickness (3/4 in. total) of expansion material is required at head and jamb
locations as well as the use of a fire retardant type sealant.
45-Minute Rated Curved Construction:
The glass blocks noted under 90-minute "rating" and those 8" x 8" x 3-7/8" sized glass block noted under 45-minute "rating" are classified for
use in masonry walls as curved window assemblies provided that the maximum allowable curvature does not exceed a ratio of 2:1 with
respect to length of radius to length of assembly width.
PC GlassBlock Products Not Fire Rated:
- All 12" x 12" sizes
- All Delphi Patterns
- All corners, endblocks and finishing units
- All Paver block units
- Frosted blocks
Refer to the latest issue of UL® Building Materials Directory as well as your local building codes and officials.
