FM 1-52, now formally identified by FM Global as Data Sheet 1-52, Field Verification of Roof Wind Uplift Resistance, provides procedures for verifying whether an installed roofing assembly has adequate resistance to wind uplift. The testing is particularly important for commercial and industrial buildings in areas exposed to tropical cyclones and high design wind speeds. FM Global’s current 1-52 document describes field testing methods for new, recovered, and reroofed above-deck roofing assemblies, while also allowing visual construction observation as an alternative in qualifying situations.
What Does FM 1-52 Testing Measure?
Roof uplift testing evaluates how well the completed roofing assembly resists negative wind pressure. Instead of relying only on laboratory ratings or product specifications, field testing checks the actual installed roof.
Depending on the roof construction, FM 1-52 provides methods including negative pressure uplift testing and bonded uplift testing. The appropriate method depends on the roof membrane, insulation, attachment method, deck construction, and other assembly characteristics. The testing is intended to identify inadequate securement, weak adhesion, or construction deficiencies that could allow wind to separate the roof system.
FM 1-52 also establishes testing pressures based on the roof’s required wind design pressure. Under the current procedure, the passing test pressure is generally determined using a 1.25 uplift testing factor applied to the applicable design wind pressure, with the roof evaluated according to its designated wind zones.
When Is FM 1-52 Field Uplift Testing Required?
The current FM Global guidance calls for field uplift testing or visual construction observation for new, recovered, or reroofed above-deck roof assemblies when both of the following conditions apply:
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The building is located in a tropical cyclone-prone region as defined by FM Global Data Sheet 1-28.
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The design wind speed is 100 mph (45 m/s) or greater.
When these conditions apply, the project should generally have satisfactory uplift testing performed in accordance with FM 1-52 or qualifying visual construction observation completed.
There are important exceptions. For example, certain new roof covers that are mechanically fastened directly to qualifying steel, wood, cementitious panel, structural concrete, or specific lightweight insulating concrete decks may not require field uplift testing when the required fastener spacing is verified.
What Happens During the Test?
A qualified testing contractor applies controlled negative pressure or uplift force to representative portions of the completed roof. Testing is performed across applicable roof zones, including field, perimeter, and corner areas where required. The objective is to determine whether the installed assembly can withstand the specified test pressure without unacceptable movement, separation, or other failure.
If a test fails or produces a suspect result, FM 1-52 provides procedures for further investigation, including roof test cuts. A roofing professional should be available to repair test areas and restore the roof to a watertight condition.
Testing also requires documentation. FM Global recommends that the final report identify the roof construction, test locations, pressures, individual test results, observations, test cuts, photographs where applicable, and equipment calibration information.
Why Is FM 1-52 Important in Florida?
For Florida commercial properties, wind uplift is a major roofing concern because of hurricane and tropical-cyclone exposure. FM 1-52 testing can provide field evidence that a roof assembly has been properly installed and can resist the required wind pressures.
However, FM 1-52 is an FM Global loss-prevention requirement, not a blanket Florida building-code requirement for every roof project. Whether testing is required on a specific property can depend on the building’s insurance requirements, FM Global recommendations, project specifications, roof assembly, location, and applicable code requirements.
Bottom Line
FM 1-52 field uplift testing verifies the wind-uplift resistance of an installed commercial roofing assembly. Under current FM Global guidance, testing or qualifying visual construction observation is generally required for new, recovered, or reroofed above-deck roof assemblies in tropical cyclone-prone areas with design wind speeds of at least 100 mph, subject to stated exceptions.
For a Florida commercial roof, the safest approach is to determine the applicable FM Global requirements before roofing work begins, confirm the specified roof assembly and wind rating, and include any required testing and documentation in the roofing contract.
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