MR-24 ROOF SYSTEM
PERFORMANCE ASSURANCE
®
®
Prospective
Butler standing seam roof systems, the
cornerstone of our company, are by far the
most widely used roof systems in the industry.
With unyielding strength, proven reliability against
the elements and durability over time, our roof
systems cover people and non-residential
buildings worldwide.
Since 1969, the MR-24® roof system has
demonstrated its outstanding performance on
buildings in nearly every possible weather element
worldwide. The MR-24 roof system has been
tested in accordance with the most demanding,
recognized specifications in the industry, such as
the U.S. Army Corps of Engineers Guide
Specification 07416 and ASTM E 1592. It has
been tested and meets the requirements for a UL
90 rating per Underwriters Laboratories U.L. 580.
According to Factory Mutual Approval Standard
4471, the MR-24 can be supplied to meet Uplift
Ratings of 1-60, 1-90 or 1-120. It is also designed
to meet the loading requirements of all Model
Building Codes and national specifications such as
IBC (International Building Code), ANSI, MBMA,
UBC, BOCA, ASCE 7 and SBC.
ROOF MOVEMENT
Roofs expand and contract with daily and
seasonal temperature changes. Unless your roof is
designed to accommodate this movement, all metal,
built-up or single ply roofs will eventually fail.
The MR-24 roof system is specifically designed
to accommodate roof movement. The system is
attached to the building’s structure with a special
clip and tab assembly formed into the double-lock
seam. Because the tab can move within the clip, the
entire roof can expand and contract freely without
sacrificing structural integrity.
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Patrick J. Fin
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THE BUTLER DIFFERENCE
ENERGY SAVINGS
Most roof systems intend to save energy.
However, few actually do so without causing
problems. For example, when thicker insulation
is used on conventional built-up roofs, fuel bills
may be reduced, but the additional insulation may
also speed-up the inevitable deterioration of the
roof surface.
Because the MR-24 roof system is metal and
moves freely with the forces of expansion and
contraction, additional insulation thickness will
not cause roof deterioration.
Also, when metal roofs are installed,
insulation is often crushed at points where the
roof is fastened to the structural members. At
these points, a thermal short circuit is created.
The MR-24 roof system utilizes special thermal
blocks to rectify this problem.
MR-24® roof system
CMR-24® roof system
VSR™ roof system
Snap-It™ roof system
Butlerib® II roof system
Reroofing systems
MR-24 ROOF SYSTEM
PERFORMANCE ASSURANCE TESTING
®
®
UNDERWRITERS LABORATORIES U.L. 580 TESTS FOR UPLIFT
RESISTANCE OF ROOF ASSEMBLIES
The U.L. test is an excellent gauge to compare
any roof deck to a standard; however, since the
test is conducted on 10’ panels lengths and the
perimeter of this test area is anchored, the test
should not be used for developing positive and
negative load tables or capacities.
Test Significance:
• Provides a comparative index of all types of roof
assemblies with respect to uplift resistance
• Evaluates systems with regard to relative loading
capacity: Class 30, 60 or 90
U.S. ARMY CORPS OF ENGINEERS
The MR-24 roof system has been
pressure tested for wind uplift in accordance
with The U.S. Army Corps of Engineers “Test
Method for Structural Performance of Standing
Seam Roof Systems by Uniform Static Air
Pressure Difference”.
Test Significance:
• Required on all projects involving the Corps
of Engineers
• Cyclic loading induces strains that help in the
evaluation of panel and/or connection fatigue
• Is used to reduce insurance rates for
end users
• Tested by an independent agency - all tests
performed in the same test fixture eliminating
test variables
• Follow-up by U.L. inspectors and labeling
service ensures that product furnished is the
same as tested
GUIDE SPECIFICATION 07416
• May be used to develop load/span tables
• Permits testing of variable purlin spacing
• Test is run to failure to establish design loads
using appropriate factors of safety
• Test sample installed representing typical edge
of roof condition
• Test sample can be configured to be representative of different roof wind uplift zones
• Can be used as a confirming test for
determining structural performance in
accordance with AISI
FACTORY MUTUAL APPROVAL STANDARD 4471
resistance, fire spread and foot traffic
The MR-24 roof system has been tested by
Factory Mutual and is listed in the FM Approval
• Used to reduce insurance rates on projects
Guide for Class 1 Panel Roofs. It can be designed
insured by a Factory Mutual insurance company
and supplied to meet the FM Uplift Ratings of
• Used to meet requirements of Factory Mutual
1-60, 1-90 or 1-120. The specific rating will
design loads
affect the gauge and purlin spacing of the system
that is provided.
• Evaluates uplift capacity of roof systems relative
to discreet loading classes
Test Significance:
• Includes testing for wind uplift, hail damage
Butler building products are constantly being improved;
therefore, the information contained herein is subject to
change without notice. Before finalizing details, contact your
nearest Butler Builder® or Butler Manufacturing Company for
the latest information.
ASTM E 1592
Test Significance:
The MR-24 roof system has been tested accord• Recognized as industry standard for uplift
ing to American Society for Testing and Materials
capacity testing
ASTM E 1592-95 “Structural Performance of Sheet
Metal Roof and Siding Systems by Uniform Static
• System is tested to failure to established design
Air Pressure Difference”.
capacity
• Used to develop load/span tables for uplift capacity
AISC Certified for
Design & Fabrication
Form No. 4830 12/05
Butler Manufacturing Company
1540 Genessee, Kansas City, MO 64102
P.O. Box 419917, Kansas City, MO 64141
Butler Buildings (Canada)
Burlington, Ontario, Canada L7M3X1
www.butlermfg.com
• Test standard prescribed by AISI to determine
factors of safety
© 2005 Butler Manufacturing Company
Printed in U.S.A.