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Fireproofing - FAQs
Fireproofing
is a complex business. The following
list of frequently asked questions has
been developed to address some of the
many issues surrounding fireproofing.
For additional help or inquiries,
contact your AVI's Fireproofing Products
Sales Representative.
Click on the
question to view response.
Monokote® MK-6®
is a gypsum based cementitious
spray-applied fire resistive material
for structural steel framed buildings.
The term
cementitious as defined by ASTM or
Underwriters Laboratories Inc. applies
to all fireproofing that is wet mixed
and then pumped as a slurry.
Cementitious does not refer to
portland cement content.
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Monokote® MK-6®
is designed to be spray-applied. All
of our testing is done with
spray-applied material. Patching and
small areas can be troweled. Care must
be taken to assure an acceptable
installation.
It does
not work this way! Thicknesses for
hourly ratings are derived from
individual UL fire resistance designs.
(We have over 120 designs to choose
from). These are classified as:
Within
these broad categories thicknesses are
dependent on:
As you can see, there are no easy
answers to this question. Consult your
Grace Fireproofing products sales
representative for assistance on
selecting the appropriate design.
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Yes, all
Monokote® Fireproofing products
manufactured by W.R. Grace & Co. -
Conn. are asbestos free.
Monokote® Accelerator
is aluminum sulfate (alum). Monokote®
Accelerator reacts with the retarder
in the gypsum. (Gypsum is normally
retarded to allow for pumping and
mixing.) This allows Monokote® MK-6®
to set in 10-20 minutes. The use of
Monokote® Accelerator with MK-6®
results in a lower installed cost.
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While not
absolutely necessary,
Monokote® MK-6®/HY® is designed to
be used with
Monokote® Accelerator - it is part
of the patented High Yield (HY)
System. If the accelerator is not
used, set time will be longer and the
product yield (board feet per bag)
will be significantly lower. The fire
resistive properties are not affected.
Drying
rate is variable and is dependent upon
many factors including -
-
Thickness
-
Temperature
-
Relative
Humidity
-
Ventilation
The material "sets" within hours but
can take many days to fully dry. As
with any spray-applied fire-resistive
material it is important to follow the
manufacturer's recommended ventilation
requirements.
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No.
Monokote® MK-6® is designed for
new construction conditions. Post
abatement respray is done over
post-removal "lockdown agents" and
Retro-Guard® is the product
recommended for these conditions. Only
Retro-Guard® has been fire tested at
UL with 12 different UL classified
lockdowns. Retro-Guard® is specially
formulated for enclosed areas and has
a distinctive blue color.
Model
building codes and numerous state laws
mandate that only the "Design
Professional" (a registered architect
or professional engineer) can make
these determinations. W. R. Grace &
Co.-Conn. can only recommend the
appropriate design and thicknesses.
All of our recommendations must be
reviewed and approved by the design
professional for the particular
project through the contractor's
normal submittal process and this
information must subsequently be
reviewed and approved by the building
code official having jurisdiction for
the specific project.
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Yes,
although we recommend that the best
surface is lightly rusted, unprimed
steel. The use of primers is governed
by Underwriters Laboratories Inc. and
must be tested in accordance with ASTM
E 736. All spray-applied fire
resistive materials require a clean
surface that is free of rolling
compounds, mill scale and other
substances that will impair the proper
adhesion of the fireproofing material.
Grace
maintains compatibility listings on
over 200 commercially available steel
primers, more than any other
fireproofing manufacturer. Check with
your Grace Fireproofing Products Sales
Representative for assistance on the
compatibility of steel primers.
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Monokote® MK-6®
is a gypsum based product and is not
intended for long term exposure to
weather. However, it's high gypsum
binder content does permit the normal
amount of exposure that is part of the
typical construction process. Our
high-density, portland cement based
product,
Monokote® Z-146 , is approved for
exterior applications where exposure
to wind, rain, and freeze/thaw cycles
are anticipated.
Yes, under
certain circumstances, Monokote® can
be painted. However, the use of paints
and sealers is governed by
Underwriters Laboratories Inc. The
surface flammability and smoke
development characteristics of the
paint or sealer must be tested in
accordance with ASTM E 84. Generally,
the paint must demonstrate a flame
spread index of less than 200 and
smoke developed of less than 450. The
paint must be compatible with gypsum
based construction materials. The
Monokote® MK-6® must be completely
dry and the paint application should
not saturate the surface.
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Absolutely
not. The Monokote® family of products
does not require, nor do we recommend,
surface sealers or water tamping. The
hard surface of gypsum-based and
cement-based cementitious fireproofing
materials delivers excellent in-place
performance, including demonstrated
resistance to air erosion and
abrasion. Monokote® is appropriate for
virtually all fireproofing
applications including air-handling
plenums. Certain types of facilities,
clean rooms and hospitals for example,
may desire a surface sealer as added
protection.
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