Testing Metal Wall Panel Systems

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Testing Metal Wall
Panel Systems
Michael Slocumb
FM Approvals
1151 Boston-Providence Highway, Norwood, MA 03062
Phone: 781-255-4841 • Fax: 781-762-9375 • E-mail: michael.slocumb@fmapprovals.com
Abstract
Combustible components contained in some metal wall panel systems (MWPS) may
exhibit self-propagating behavior in the event of even a small fire. MWPS intended for the
building envelope are subjected to natural hazards such as wind, hail, and wind-blown
debris.
FM Approvals tests MWPS for combustibility according to FM Approvals Standard 4880,
resistance to natural hazards according to Standard 4881, and smoke generation rate
according to Standard 4882.
MWPS that receive approval recognition have been evaluated to ensure that they will
perform their intended functions and maintain the integrity of the building envelope for the
stated design conditions.
Speaker
Michael S. Slocumb — FM Approvals – Norwood, MA
Micha el S. Slocumb is a senior engineer in the Materials Group at FM Approvals. He
holds a BS degree in business from Assumption College and a BS in mechanical engineering
from the University of Massachusetts. He has almost ten years of experience in testing
and research of building materials. Currently, he is focused on testing wall and roof panel
systems and pliable roof systems.
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This paper describes the development of
FM Approvals Standards 4880, 4881, and
4882. In addition, an explanation on selecting
a properly rated system is provided.
Metal wall panel systems (MWPS) are
examined and approved by FM Approvals
through the use of the following three standards:
• Approval Standard for Class 1 Fire
Rating of Insulated Wall or Wall and
Roof/Ceiling Panels, Interior Finish
Materials or Coatings, and Exterior
Wall Systems (Standard 4880)
• Approval Standard for Class 1
Exterior Wall Systems (Standard
4881)
• Approval Standard for Class 1
Interior Wall and Ceiling Materials
or Systems for Smoke-Sensitive
Occupancies (Standard 4882)
Standard 4880
Standard 4880 specifies the fire resistance
performance requirements for Class
1 fire-rated wall panel, wall and roof/ceiling
panel, interior finish materials or coating,
and exterior wall system assemblies.
Performance is dependent in part on
fasteners, adhesives, and other accessories
used in construction and the substrate
over which they are installed. Therefore,
assemblies, and not products or parts,
are examined and approved. Based upon
performance, approved installation height
ratings are maximum 30 ft. (9.1 m) or 50 ft.
(15.2 m), or no height restriction.
Products approved to Standard 4880
will not allow a self-propagating fire and
may not require the use of an automatic
sprinkler system to protect a building.
The most common materials examined
are field- or factory-fabricated panels. These
panels are connected to one another and to
the substrate with various types of closures
and joint treatments. They consist of a facer
attached to an insulating core material. The
facer could be aluminum (foil), painted or
npainted steel, gypsum wallboard, plastic,
masonry, or other cementitious material.
The insulating core material consists of a
rigid plastic foam or mineral wool. Samples
are examined at the maximum core thickness,
minimum facing thickness, minimum
panel width, and maximum facer coating
thickness sought for approval.
Interior finish materials are also examined.
They can be reinforced or nonreinforced
thermoplastic or thermoset materials such
as polyvinyl chloride (PVC) or fiberglassreinforced
panels (FRP ). Interior finish
materials also consist of masonry block,
brick, precast concrete, or gypsum board.
Samples are provided at the maximum core
thickness, minimum facing thickness, and
minimum width sought for approval.
Interior wall or ceiling coating systems
include fire-retardant-treated cellulose,
mineral or glass fiber insulations, and intumescent
paints and mastics. These products
are usually applied by trowel, brush,
spray rig, or roller. Samples are provided
at the minimum thickness and over the
most critical substrate for which approval
is sought.
Examples of exterior wall systems
are metal, concrete, composite, or glass.
Samples are provided at the minimum
material thickness, maximum insulation
thickness, and over the most critical substrate
for which approval is sought.
The general requirements for examination
according to Standard 4880 are as
follows:
1. Witness sample manufacture
2. R eview of component formulations
and/or specifications
3. Flammability characterization of
combustible components
4. R oom fire test
5. 25-ft. (7.6-m) High Corner Test (for
approval to 30 ft. [9.1 m])
6. 50-ft. (15.2-m) High Corner Test (for
approval greater than 30 ft. [9.1 m])
7. 16-ft. (4.9-m) High Parallel Panel
Test (for approval greater than 30 ft.
[9.1 m])
8. Surface-burning characteristics (if
plastic foam core) per ASTM E84
9. Small-scale identification tests (density,
ignition properties, heat content,
ash content)
Items 8 and 9 are for identification or
local building code requirement purposes
only. No limits are placed on test values.
An FM Approvals representative must
witness production of all plastic components
(e.g., polyol or isocyanate of any thermoset
plastic foam core) at the manufacturing
facility. Additionally, the production of
sample panels must be witnessed by an FM
Approvals representative.
The flammability characterization is a
small-scale test to measure the flammability
properties of plastic components. The
FM Approvals Fire Propagation Apparatus is
used for this test, and it is performed according
to ASTM E2058. This test measures the
following material flammability properties:
• Convective flame spread parameter
(FSPc), a measurement of or correlation
to flame spread along eaves in a
corner
• Chemical heat of combustion (measurement
of heat content)
• E ffective heat of gasification
• Critical heat flux for ignition (measurement
of maximum heat flux at
which no ignition occurs)
• Chemical heat release rate (total of
CO and CO2 generation)
• Convective heat release rate (CO
generation)
• Thermal response parameter resistance
to ignition (measurement of a
resistance to ignition)
For Class 1 Approval to maximum height
of 30 ft. (9.1 m) of inert-faced thermoset
plastic foam core panels without a 25-ft.
(7.6-m) High Corner Test, performance is
adequate if FSPc ≤ 0.39 s-1/2. The FSPc can
also be used to screen candidates for a
25-ft. (7.6-m) High Corner Test, since this
Testing Metal Wall
Panel Systems
test is required if 0.40 < FSPc < 0.47 s-1/2.
The 25-ft. (7.6-m) High Corner Test is not
recommended if FSPc ≥ 0.47 s-1/2 (unless
walls only, with noncombustible ceiling).
The room corner test is a full-scale test
of a completed wall, wall-and-ceiling, or ceiling-
only assembly. It is performed according
to Uniform Building Code Standard No.
26-3, Room Fire Test Standard for Interior of
Foam Plastic Systems. It is used to measure
performance of assembly in response to a
real corner. A corner fire is considered the
most critical area in which a fire can occur.
The wall area exposed to this test consists
of two 8- x 8-ft. (2.4- x 2.4-m) exposed area
intersecting walls. The ceiling area exposed
to this test is one 8- x 8-ft. (2.4- x 2.4-m)
exposed area ceiling. The fire source is a 15-
by 15-in. (380- by 380-mm) square crib of
1½-in.- (38-mm-) square Douglas fir sticks
conditioned to specified moisture content
and placed at the intersection of the panel
walls. It is ignited using 1 lb. (0.45 kg) of
shredded wood excelsior and 4 oz. (0.12 l)
of ethanol. The test is run for 15 minutes.
For acceptance, the assembly must (a) not
support a self-propagating fire that extends
to outer extremities of the test area, (b) not
generate excessive smoke during test period,
and (c) sustain the applied load (if any)
for the duration of the test period.
The 25-ft- (7.6-m) High Corner Test is
a full-scale test of a completed wall-only
or wall-and-ceiling assembly. It is intended
for inert-faced thermoset-plastic-core panels
where 0.40 < FSPc < 0.47 s-½ or all
other combustible-core panels are under
the scope of Standard 4880. This test is
used to measure performance of a complete
assembly in response to a fire in the
corner of a room. The test is made up of a
free-standing structural steel frame with
51 ft., 6 in.- (15.7-m-) and 39 ft., 3 in.-
(12.0m-) long intersecting walls. Samples
are installed on the inside of the steel frame.
The fire exposure source is 750 lb. (340 kg)
of oak pallets, which are ignited with cellucotton
rolls soaked in gasoline, and the test
is performed for 15 minutes. See Figure 1.
For approval to a maximum height of 30
ft. (9.1 m), assemblies using this test method
cannot support a self-propagating fire
that reaches any of the limits of the 25-ft.
(7.6-m) structure as evidenced by flaming or
material damage.
The 50-ft. (15.2-m) High Corner Test
is another full-scale test of a completed
wall-only or wall-and-ceiling assembly. It is
intended for inert-faced thermoset-plasticcore
panels where FSPc ≤ 0.39 s-1/2 and
which have passed the UBC 26-3 room test,
or all other combustible-core panels under
the scope of Standard 4880 that passed
the 25-ft- (7.6-m) High Corner Test. Like all
other large-scale Standard 4880 tests, this
test is used to measure performance of a
complete assembly in response to a fire in
the corner of a room. The test is made up
of a freestanding structural steel frame with
20- x 50-ft.- (4.6- x 15.2-m-) long intersecting
walls with a triangular ceiling. Samples
are installed on the inside of the steel frame.
The fire exposure source is 750 lb. (340 kg)
of oak pallets, which are ignited with cellucotton
rolls soaked in gasoline. The test is
for 15 minutes. See Figure 2.
For approval to a maximum height of 50
ft. (15.2 m), an assembly must meet requirements
for 30-ft.
(9.1-m) approval.
Additionally, the
same assembly
must not support
a self-propagating
fire in the
50-ft. (15.2-m)
High Corner Test
that reaches any
of the limits of
the 50-ft. (15.2-
m) structure as
evidenced by
flaming or material
damage.
For approval
to unlimited
height, an
assembly must meet requirements for 50-ft.
(15.2-m) approval and experience no ignition
of the ceiling in the 50-ft. (15.2-m) High
Corner Test.
The 16-ft. (4.9-m) parallel panel test
is a medium-scale test of finished wall
panels but not a complete assembly. This
test measures chemical heat release rate.
It is intended to replace the 25-ft. (7.6-m)
and 50-ft. (15.2-m) High Corner Test for
assemblies that do not have thermoplastic
foam cores or a peak chemical heat release
rate below a set value. The test is made up
of parallel panels facing one other—each 16
ft. (4.9 m) high by 42 in. (1.1 m) wide with
a vertical panel joint incorporated in the
center. The panels are separated by 21 in.
(0.53 m). The ignition source is a 360 kW
propane sand burner located at the base
and between the panels. See Figure 3.
Approval is granted based on the following
(see Table 1):
Surface burning characteristic tests
are performed in accordance with ASTM
E84, Test Method for Surface Burning
Characteristics. The test is performed on
only the bare thermoset or thermoplastic
core of building panels. Flame spread
distance and quantity of smoke developed
from a core surface are measured. Tests are
conducted to satisfy building code requirements
or for identification purposes, as FM
Approvals places no limits on values.
For inert-faced noncombustible core
(i.e., mineral wool) panels, approval with an
unlimited height rating can be granted with
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Figure 1 – 25-ft (7.6-m) high corner test layout.
Figure 2 – 50-ft. (15.2-m) high corner
test layout.
one large-scale test—a UBC 26-3 room test.
However, the core must be proven noncombustible
with the following tests:
1. ASTM D482, where the ash content
of core must be at least 90%
2. ASTM E2058, where there must be
no visible flaming for 15 minutes
when tested in a combustion test
with an applied heat flux of 50 kW/
m2 in air enriched to 40% oxygen
3. ISO 1716 (oxygen bomb), where an
average of three heat-of-combustion
tests cannot exceed 2.0 kJ/g (860
BTU/lb.)
For noninert-faced panels, all other
large-scale tests must be performed.
Other small-scale identification tests
are performed and serve as fingerprints
of parts of building panels. The results of
these tests can be used to judge approval of
future assembly revisions.
If an MWPS with a polyisocyanurate core
were to seek approval with a 30-ft. (9.1-m)
rating, for example, the following would be
required:
1. Witness blending of polyol portion of
polyisocyanurate core
2. Witness manufacture of MWPS
3. R eview of component formulations
and/or specifications
4. Flammability characterization of core
with FSPc ≤ 0.39 s-1/2
5. UBC 26-3 room fire test
6. Surface burning characteristics (if
plastic foam core) per ASTM E84
7. Small-scale identification tests (density,
ignition properties, heat content,
ash content)
Standard 4881
Standard 4881 sets the performance
requirements for Class 1 exterior wall panels
when exposed to natural hazards such
as the cyclic pressure of wind, simulated
hail, and wind-borne debris. Examples are
metal-only or composite panels.
The following describes the pressure
dynamics around a building for a wind
event (see Figure 4).
Due to pressure dynamics and other
factors affecting the fluid dynamics of air
around a building, pressure working from
the inside of the building toward the outside,
or Poutward, can reach a level twice as
high as the pressure acting from the outside
of the building toward the inside, or Pinward.
Standard 4881 provides wind-loading
classification ratings
in multiple windstorm
zones: HM–Hurricane
with missile impact,
H–Hurricane (no missile
impact), and
NH–Nonhurricane
(intended for assemblies
installed in
areas not prone to
hurricanes). Two missile
impact ratings
exist to go along
with the HM rating.
Small-missile (SM)
impact testing consists
of ten 0.7-oz.
(2-g) steel balls shot
out of a small cannon
at approximately 90 mph (145 kmph).
Large-missile (LM) impact testing consists
of two-by-four lumber shot from a cannon
at approximately 35 mph (56 kmph). Missile
impact testing simulates windborne debris
in the event of a hurricane. Therefore, along
with the wind load rating based on the
tested pressure, available zone classifications
are Zone NH, Zone H, Zone HM, Zone
HM-SM, and Zone HM-LM.
The general requirements for examination
are as follows:
1. Must be approved or in the process
of being approved according to
Standard 4880
2. Witness sample manufacturing by
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Figure 3 – 16-ft. (4.9-m) parallel panel test layout.
Figure 4 – Outward pressure vs. inward pressure.
Sample Consisting of… Maximum Approved If the Peak Chemical Heat
Height Release Rate < or =
Combustible walls with 30 ft. (9.1 m) 1100 kW
noncombustible ceiling
Combustible walls with 30 ft. (9.1 m) 830 kW
combustible ceiling
Combustible walls with No height restriction 830 kW
combustible or
noncombustible ceiling
Table 1 – 16-ft. (4.9-m) parallel panel approval matrix.
representative of FM Approvals (only
if panels are not currently approved)
3. Simulated wind loading
4. Simulated windborne debris (optional)
5. Hail resistance
For simulated wind loading, samples
are subjected to a set of static and a set of
cyclic air pressure differentials. Samples
are usually of the thinnest and widest
offering attached to the thinnest and leaststrong
girts sought for approval and are
installed in a 14- x 16-ft. (4.3- x 4.9-m) steel
frame. A minimum of one sample is tested.
All simulated wind loading is based upon
Pinward, subsequently referred to as P, which
is selected by the test sponsor. A minimum
P of 30 psf (1.4 kPa [kilopascal]) is required,
and approval is granted in increments of 5
psf (0.2 kPa) P. Approval is granted as a set;
P, – Poutward. The ratio of Poutward to P is based
on a pressure multiplier of 1.4 or 2.0, which
is also selected by the sponsor. The same
sample can be used, but is not required to
be used, for both sets of simulated wind
loading tests. Successful testing is based
upon the sample’s showing no signs of
cracking or any other failure. Examples of
“any other failure” include delamination
of facer from core, fastener withdrawal,
joint disengagement, or any type of plastic
deformation.
For a Zone H rating, a minimum of one
sample is tested. No wind-borne debris
testing is performed prior to cyclic testing.
For a Zone HM rating, a minimum of
four samples are tested. Three samples
are windborne-debris tested prior to cyclic
testing.
Static and cyclic loading are performed
according to Tables 2, 3, and 4.
Standard 4881 also allows for two hail
resistance ratings, namely “severe” and
“moderate.” Severe hail testing consists of
1.75-in.- (44-mm-) diameter ice balls shot
at 70 mph (113 kmph), and the moderate
hail rating consists of 1.5-in.- (38-mm-)
diameter ice balls shot at 63 mph (101
kmph). The sample is a 3- x 3-ft. to 4- x 4-ft.
(0.9- x 0.9-m to 1.2- x 1.2-m) specimen with
a center seam incorporated in the center of
the sample. A successful test is a sample
that shows no signs of cracking or splitting.
Standard 4882
Standard 4882 sets the performance
requirements for interior wall and ceiling
materials for smoke-sensitive locations.
Smoke-sensitive occupancies include, in
order (from a property-loss-prevention perspective)
of most- to least-sensitive: cleanroom
or similar occupancies, pharmaceutical
manufacturing and storage areas, and
food preparation and storage areas or similar
occupancies.
Approval is granted with height ratings
of 10 ft. (3.0 m), 30 ft. (9.1 m), 50 ft. (15.2 m),
and no height restrictions in two categories:
(1) clean-room or similar occupancies; and
(2) pharmaceutical manufacturing and storage
areas, and food preparation and storage
areas or similar occupancies.
Standard 4882 requires that a product
have a fire and smoke rating. Like Standard
4880, products approved to Standard 4882
will not allow a self-propagating fire and
may not require the use of an automatic
sprinkler system to protect a building.
Additionally, however, products approved
to Standard 4882 will produce low levels of
smoke during any fire. Smoke damage can
result in significant loss of stored product,
in-process product, and significant busi-
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Static Testing for All Zones
Load When Load When Loading Direction Duration
Multiplier = 1.4 Multiplier = 2.0
0.5P 0.5P Inward 60 seconds
1.0P 1.0P Inward 60 seconds
0.7P 1.0P Outward 60 seconds
1.4P 2.0P Outward 60 seconds
Table 2 – Static test loads.
Cyclic Testing for Zones H & HM (9000 Cycles)
Loading Sequence Loading Direction Air Pressure Cycles # of Air Pressure
Cycles
1 Inward 0.2P to 0.5P 3500
2 Inward 0.0P to 0.6P 300
3 Inward 0.5P to 0.8P 600
4 Inward 0.3P to 1.0P 100
5 Outward 0.3P to 1.0P 50
6 Outward 0.5P to 0.8P 1050
7 Outward 0.0P to 0.6P 50
8 Outward 0.2P to 0.5P 3350
Table 3 – Zones H and HM cyclic test loads and cycles.
Cyclic Testing for Zone NH (1048 Cycles)
Loading Loading Air Pressure # of Air Pressure
Sequence Direction Cycles Cycles
1 Inward 0.0P to 0.6P 12
2 Inward 0.0P to 0.8P 1
Repeat loading sequence 1 and 2 an additional 4 times prior to sequence 3.
3 Inward 0.0P to 1.0P 1
4 Outward 0.0P to 0.6P 12
5 Outward 0.0P to 0.8P 1
Repeat loading sequence 4 and 5 an additional 4 times prior to sequence 6.
6 Outward 0.0P to 1.0P 1
Repeat loading sequence 1 through 6 an additional 7 times.
Table 4 – Zone NH cyclic test loads and cycles.
ness downtime in
smoke-sensitive
industries.
Sample products
are usually
supplied as individual sheets or field- or
factory-fabricated panels. They can be
homogenous material, reinforced plastic
material, or composite panels. Any facers
can be plastic, aluminum, steel, gypsum, or
masonry. Samples are usually tested at the
maximum thickness sought for approval.
In a simplified form, except for the 10-ft.
(3.0-m) rating that requires only a UBC
26-3 room fire test for the fire rating, the
same Standard 4880 tests for the respective
height rating are used to satisfy the fire rating
portion of Standard 4882.
For the smoke-rating potion, requirements
are as follows:
Clean room or similar
occupancies
1. Homogenous material 0.25- to 1-in.
(6- to 25-mm) thick (e.g., PVC sheet):
ASTM E2058 (fire propagation apparatus)
with a fire propagation index
(FPI) ≤ 6 (m/s1/2)/(kW/m)2/3
All other materials (e.g. composite
materials): 8-ft. (2.4-m) parallel
panel test with an ignition source of
60 kW and the following criteria:
a. Visual propagation height of ≤ 6
ft. (1830 mm)
b. Maximum heat flux of 40 kW/m2
at 4 ft. (1220 mm)
c. Decay of at least half of the
maximum chemical heat release
rate one minute after burner termination
d. Decay of at least a factor of four
of the maximum chemical heat
release rate two minutes after
burner termination
2. Homogenous material 0.25- to 1-in.
(6- to 25-mm) thick (i.e., PVC sheet):
ASTM E2058 (fire propagation
apparatus) with a smoke development
index (SDI) ≤ 0.40 (m/s1/2)/
(kW/m)2/3
3. All other materials (e.g., composite
materials): 8-ft. (2.4-m) parallel
panel test with an ignition source of
60 kW and the following criteria:
a. Maximum smoke generation rate
≤ 0.23 g/s
b. Smoke generation rate at 12
minutes ≤ 0.07 g/s
c. Total smoke generated ≤ 60 g
4. 16-ft. (4.9-m) parallel panel test,
with an ignition source of 360 kW
with an average smoke generation
rate ≤ 240 mg/s
5. ASTM E84 tests with:
a. Flame-spread index (FSI) ≤ 25
b. Smoke-developed index (SDI) ≤
450
Pharmaceutical manufacturing/storage
areas, food preparation/storage areas, or
similar occupancies:
1. 16-ft. (4.9-m) parallel panel test with
an ignition source of 360 kW, with
an average smoke generation rate ≤
240 mg/s
2. ASTM E84 tests with:
a. FSI ≤ 25
b. SDI ≤ 450
As illustrated, the requirements for clean
room or similar occupancies are noticeably
more stringent, since these occupancies
are more sensitive with regards to property
loss prevention than pharmaceutical manufacturing/
storage areas, food preparation/
storage areas, or similar occupancies.
Selecting a Properly Rated
Standard 4880/4881/4882
System
Rates for Standards 4880 and 4882
are predetermined by the nature of the
panel or the industry in which assemblies
are placed in service. For example, a
steel-faced panel with a polyisocyanurate
core would be recognized under Standard
4880 in the category of “metal-faced with
combustible core.” A steel-faced panel with
a mineral wool core would be recognized
under Standard 4880 in the category of
“metal-faced with noncombustible core.”
However, a customer does choose a height
installation rating based on the buildings
on which the panel would be installed.
Height installation ratings are 10-ft. (3-m),
30-ft. (9.1-m), 50-ft. (15.2-m), and no height
restriction. Examples of typical Standard
4880 ratings are “Class 1 metal-faced with
noncombustible core for installation with
no height restriction,” “Class 1 metal-faced
with combustible core for installation to
30 ft. (9.1 m),” and “Class 1 metal-faced
with combustible core for installation with
no height restriction.” Examples of typical
Standard 4882 ratings are “Class 1 interior
wall panels for pharmaceutical manufacturing
and storage areas, food preparation,
and storage areas with or similar occupancies
for installation to 30 ft. (9.1 m)” or
“Class 1 interior wall panels for clean rooms
for installation to 10 ft. (3 m).”
Standard 4880 panels can be used as
exterior panels, which are examined under
Standard 4881 (Standard 4880 recognition
is a prerequisite for Standard 4881 examination).
Approved Standard 4881 ratings
and limitations include those shown in
Table 5.
Standard 4881 establishes—along with
hail and missile impact (wind-blown debris)
ratings—pressure ratings for wall panel
systems. The movement of air around a
building affects the pressure around a
building. FM Global Loss Prevention Data
Sheet (FMGLP DS) 1-28, Design Wind Loads,
available for public reference, is a reference
tool used to develop recommended pressure
ratings for Standard 4881. FMGLP DS 1-28
provides pressures resulting from wind and
other k factors for common building shapes.
Some information must be realized before a
recommended pressure rating can be developed.
Typically, this information includes,
but is not limited to, a market area for sale
of panels. From the market area, the highest
wind speed is obtained from FMGLP DS
1-28. The following other information of a
most critical status to obtain a maximum
pressure is obtained from FMGLP DS 1-28:
• Ground classification
• R oof slope
• Type of building (enclosed, partially
enclosed)
To provide an example for choosing a
rating for Standard 4881: If a customer
requests approval recognition in a market
area of South Korea, the maximum 3-
second gust (used by FM Global) basic wind
speed in this zone is 130 mph (58 m/s).
For determination of the design pressures
(used by FM Global for acceptance)
that relate to the wind speed for this region,
the following is also obtained:
• Ground classification C, which is
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Thickness/ W idth Max. Hail W ind Load W ind Load Min. Support Min. Support
Securement Height Resistance Rating Rating & Steel Steel Yield
Rating & Zone Spacing Thickness Stress
Table 5 – Standard 4881 approval specifications.
relatively open terrain with scattered
obstructions
• R oof slope ≤ 10 degrees
• E nclosed building (see FMGPLP DS
1-28, page 34 for definition)
FM Global requires a 2.0 safety factor
for all design pressures. The wall corners
are the most critical areas of a building
since they are prone to the highest
pressures. Therefore, the corner pressures
govern. The 130-mph (58-m/s), 3-second
gust basic wind speed and other information
result in the corner inward and corner
outward design pressures shown in Table 6.
Installation height is limited to the
Standard 4880 rating and Standard 4881
pressure rating, since pressures vary with
building height. Assume the height installation
rating is 30 ft. (9.1 m).
Therefore, targeted design pressures
according to Standard 4881 are as follows:
(88 psf inward, 120 psf outward)design, 30 ft
or
(4.2 kPa inward, 5.7 kPa outward)design, 9.1 m
For examination, Standard 4881
requires that a customer choose a pressure
coefficient. The pressure coefficient is used
to determine the outward pressure based
on a chosen inward pressure. The outward
pressure is calculated as follows:
outward pressureApproval =
pressure coefficient x inward pressureApproval
Due to the dynamics of air around a
building and other factors, a pressure coefficient
of 1.4 is typically used for building
heights less than or equal to 60 ft. (18.3
m). A pressure coefficient of 2.0 is used for
buildings greater than 60 ft. (18.3 m).
Targeted approval pressures from examination
according to Standard 4881 must be
equal or greater than the design pressures.
A targeted inward approval pressure of 90
psf (4.3 kPa) is accompanied by a targeted
outward approval pressure of 126 psf (6.0
kPa), based on a pressure coefficient of 1.4.
Therefore, the following is concluded for
the selection of pressures:
(90 psf inward, 126 psf outward)Approval, 30 ft. ≥
(88 psf inward, 120 psf outward)design, 30 ft.
or
(4.3 kPa inward, 6.0 kPa outward)Approval, 9.1 m
≥ (4.2 kPa inward, 5.7 kPa outward)design, 9.1 m
The chosen P for Standard 4881 testing
is therefore 90 psf (4.3 kPa) with a pressure
coefficient of 1.4.
Standards 4880 and 4881 should be
considered simultaneously with regards to
height installation, since both play a role in
height installation. Wall panel approval recognition
is limited to the maximum girt span
examined in the pressure tests, up to a maximum
94 in. (2.38 m) on center. Additional
examination is required for greater spans.
FMGLP DS 1-29, Roof Deck Securement
and Above-Deck Roof Components, provides
a hailstorm hazard map for the United
States. This is helpful for determining the
selection of the hailstorm rating—severe or
moderate—for a market area.
An HM-SM (small missile) rating is typically
required in a market area where the
wind speed is equal to or greater than 100
mph, and an HM-LM (large missile) rating
is typically required in a market area where
the wind speed is equal to or greater than
110 mph.
REFERENCES
ASTM, 1916 Race Street, Philadelphia,
PA 19103
ASTM D482, Standard Test Method for
Ash From Petroleum Products.
ASTM E84, Standard Test Method for
Surface Burning Characteristics of
Building Materials.
ASTM E2058, Standard Test Methods for
Measurement of Synthetic Polymer
Material Flammability Using a Fire
Propagation Apparatus (FPA).
FM Approvals, 1151 Boston-Providence
Turnpike, Norwood, MA 02062
FM Approvals Standard 4880 — Class 1
Fire Rating of Insulated Wall or Wall
and Roof/Ceiling Panels, Interior
Finish Materials or Coatings, and
Exterior Wall Systems.
FM Approvals Standard 4881 — Class 1
Exterior Wall Systems.
FM Approvals Standard 4882 — Class
1 Interior Wall and Ceiling Materials
or Systems for Smoke-Sensitive
Occupancies.
Test Procedure Class Number 4880:
FM Approvals 50-ft. (15.2-m) High
Corner Test.
Test Procedure Class Numbers 4880
and 4882: FM Approvals 16-Ft. (4.9-
m) High Parallel Panel Test.
Test Procedure Uniform Building Code
Standard 26-3: Room Fire Test Standard
for Interior of Foam Plastic
Systems.
Test Procedure Class Number 4880:
FM Approvals 25-Ft. (7.6-m) High
Corner Test.
FM Global Research, 1151 Boston-
Providence Turnpike, Norwood, MA
02062
FM Global Property Loss Prevention
Data Sheet 1-28, Design Wind
Loads.
FM Global Property Loss Prevention Data
Sheet 1-29, Roof Deck Securement
and Above-Deck Roof Components.
International Organization for
Standardization, Casse Postale 56,
CH1211 Geneva 20, Switzerland
ISO 1716:2002: Reaction to Fire Tests for
Building Products — Determination
of the Heat of Combustion.
3 2 • S l o c u mb 2 8 t h R C I I n t e r n a t i o n a l C o n v e n t i o n a n d T r a d e S h o w • M a rc h 1 4 – 1 9 , 2 0 1 3
130 MPH (58 m/s) Zone Basic Design Pressures
With 2.0 Safety Factory Included
Building Height Corner Inward, psf Corner Outward, psf
(kPa) (kPa)
30 ft. (9.1 m) 88 (4.2) 120 (5.7)
60 ft. (18.3 m) 104 (5.0) 140 (6.7)
90 ft. (27.4 m) 112 (5.4) 209 (10.0)
Table 6 – Pressures at typical building heights for 130 mph (58 m/s) zone.