Dow Protected Membrane Roof EN - Manual (Page 20)

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Overview
Fire and wind ratings are
required to meet building code
requirements. Typically, a PMR
assembly, including roof deck,
membrane, insulation and
ballast, is tested in exactly the
same configuration as would
be constructed in the field. No
deviation from the component
specification is allowed.
Underwriters Laboratories Inc.
(ULI), Underwriters Laboratories
Canada (ULC) and Factory
Mutual (FM) have developed test
methods to rate the fire and
wind properties of assemblies.
For the most current listings,
contact Dow at 1-866-583-BLUE
(2583).
Test Methods
FIRE RESISTANCE RATINGS –
FIRE WITHIN A BUILDING
Both ULI and ULC test roof
assemblies based on the type of
fire exposure. For fires originating
within a building, roof assemblies
are assessed using either ANSI/UL
263 or CAN/ULC S101-M.
When testing for fires originat-
ing within a building, a full-scale
roof system is exposed to a
controlled fire in order to assess
a construction/assembly that
can contain a fully developed
fire. The Fire Resistance Rating
represents the time it takes for
the temperature on the unex-
posed side of the assembly to
increase by 250°F (121°C).
A sample measuring approxi-
mately 14' x 17' (4.3 m x 5.2 m)
is used, including the decking
material, any suspended ceiling,
hangers, insulation, etc. The
sample is then exposed to a fire
with temperatures reaching 1,000°F
(537°C) at five minutes and then
1,700°F (927°C) for a specified
time. During the test, a load is
applied to the floor to represent
the maximum load the joists are
designed to support.
EXTERNAL FIRE
PERFORMANCE OF
A ROOF ASSEMBLY
The fire resistance performance
of roof coverings exposed to
simulated fire source originating
outside a building is conducted
in accordance with ULI 790
(ASTM E108) or CAN/ULC S107-M.
Three classifications are available.
Class A roof covering:
• Effective against severe fire test
exposures
• Provides a high degree of fire
protection
• Not expected to produce flying
embers
• Does not slip from position
during the test
Class B roof covering:
• Effective against moderate fire
test exposures
• Provides a moderate degree of
fire protection
• Not expected to produce flying
embers
• Does not slip from position
during the test
Class C roof covering:
• Effective against light fire test
exposures
• Provides a light degree of fire
protection
• Not expected to produce flying
embers
• Does not slip from position
during the test
Note: PMR assemblies ballasted
with a minimum of 9 lb/ft
2 (44
kg/m 2 ) of stone ballast (or pavers
installed with a maximum gap of
1/4" [6 mm]) achieve a Class A
rating.
FM TESTS FOR
WIND PERFORMANCE
Factory Mutual approved roof
assemblies are only required when
the building is insured by FM
Global. Building code authorities
may recognize some FM
standards; however, they do not
require the use of FM approved
or accepted products and systems.
FM 4450, “Approval Standard
for Class 1 Insulated Steel Deck
Roofs,” and FM 4470, “Approval
Standard for Class 1 Roof
Covers,” are two recognized
laboratory test methods for
determining the wind-uplift
resistances of roof assemblies.
FM 4450 and FM 4470 are the
basis of FM’s 1-60, 1-90, 1-120,
etc., approvals. For example, a
Class 1-60 design resists a 60
lb/ft
2 (2.88 kPa) uplift pressure
for one minute without loss of
pressure.
Dow has a PMR system rated
FM 1-90 that adheres
STYROFOAM
™ Brand Extruded
Polystyrene Foam Insulation to
a BUR assembly with asphalt.
This system can be used on both
steel and concrete roof decks.
Loose-laid single-ply roof mem-
branes with ballast are not listed
in the FM approval guide since
there are not methods to test
these systems for wind uplift.
Loose-laid systems can be
“accepted” by FM if the assem-
bly is ballasted in accordance
with FM Loss Prevention Guide
1-29 and reviewed by the local
FM engineering office.
REQUIREMENTS FOR
BALLASTED ROOF
ASSEMBLIES
PMR assemblies should be
ballasted according to the
requirements listed in “Ballast”
on page 11.
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