Conditions, issues and ratings, Overview, Test methods – Dow Protected Membrane Roof EN User Manual
Page 21: Fire resistance ratings – fire within a building, External fire performance of a roof assembly, Fm tests for wind performance, Ibc requirements for ballasted roof assemblies
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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.
A sample measuring approxi-
mately 14' x 17' 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
at five minutes and then 1,700°F
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 UL 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
of
stone ballast (or pavers installed
with a maximum gap of 1/4")
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
uplift pressure for one
minute without loss of pressure.
Dow has a PMR system rated
FM 1-90 that adheres
STYROFOAM
™
extruded poly-
styrene insulation to a BUR roof
assembly with asphalt. This sys-
tem can be used on both steel
and concrete roof decks. Loose-
laid single-ply roof membranes
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 assembly is ballast-
ed in accordance with FM Loss
Prevention Guide 1-29 and
reviewed by the local FM engi-
neering office.
IBC REQUIREMENTS
FOR BALLASTED ROOF
ASSEMBLIES
The International Building
Code (IBC) requires that ballast-
ed roofing assemblies, including
PMR assemblies, be ballasted in
accordance with ANSI/SPRI RP-4.
This standard can be down-
loaded (free of charge) at
www.spri.org
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Conditions, Issues and Ratings
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