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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

®™Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow

Conditions, Issues and Ratings

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