Commercial Roof System Testing: Wind Uplift, Fire Resistance, and More

The roof is arguably the most important piece of any building. It protects the facility, the equipment, the inventory, and most importantly, the people operating beneath it. That’s why proper testing is so important when it comes to selecting the right roof for a facility. Commercial roof test methods vary from wind uplift to fire resistance and many more.

Identifying Necessary Roof Tests for a Facility

Before diving into the various commercial testing methods, you must first look at geography. Where your facility is located will dictate most of the required and/or recommended test methods for your roof system. For example, the coastal areas require a significantly stronger wind uplift score than a facility located in the Midwest.

Commercial roof testing will also vary depending on the building and its intended usage. For example, a plaza or multi-tenant facility will require a stronger fire resistance rating to reduce the risk of flame spread.

Always refer to your local building codes and your insurance provider to determine what roof tests are required for your facility.

Types of Commercial Roof Testing

The two most commonly required commercial roof tests are wind uplift and fire resistance.

Wind Uplift

Wind uplift measures the amount of pressure it takes to pull a roof system from the deck. It is measured in pounds per square foot. Wind speed maps are available to see what is required for your area. The higher the wind speed, the higher the uplift required. High Velocity Hurricane Zones (HVHZ) like Miami-Dade County in Florida, require the highest wind uplift.

The test method is attaching or adhering the roof system to a wind uplift table. A vacuum chamber is applied to the test roof and a manometer measures the pounds of pressure inside the test chamber When the roof system detaches, the gauge stops and that is the wind uplift is noted in pounds per square foot (psf).

Wind uplift tables vary in size. For example, the wind uplift table at Simon Roofing’s laboratory is 12’ x 24’. For those tested on a 5’ x 9’ table, the maximum wind uplift that can be measured is 90 psf. You’ll notice an asterisk on these test results. For fully adhered roof systems over concrete or gypsum decks, a 2’ x 2’ test is generally performed.

Fire Resistance

There are two main types of fire testing – external fire (also known as spread of flame or burning brand) and internal fire.

External Fire

External fire measures the spread of a flame on a roof system. To test external fire or spread of flame, the roof system is set up at the appropriate slope and a fire is started at the lowest part. It burns for 10 minutes and how far the spread reaches at the end of that time determines the classification.
External fire or spread of flame is classified into three main groups:
• Class A: Fire does not spread past 6’ (on an 8’ deck)
• Class B: Fire does not spread past 8’
• Class C: Fire does not spread past 13’
Make note of the slope of the roof system during the test. The higher the slope, the harder it is to pass the test.

Internal Fire

Internal fire measures a roof system’s ability to prevent flame from happening from the underside of a building. It is especially important in multi-tenant facilities like apartment complexes or shopping plazas.

To test internal fire, the roof system is built on top of a metal deck inside of a chamber. The test monitors BTUs to determine how much heat the roof system contributes to the flame. Internal fire ratings are pass/fail, with a 1 score as a passing grade. Non-combustible roof decks like concrete will not require this test.

In addition to wind uplift and fire ratings, other test methods include hail damage and leak testing.

• Hail Damage Testing. This roof test is sometimes required for facilities with Factory Mutual insurance. The test consists of a steel ball being dropped onto the roof system from 14.5’. A moderate hail rating uses a 1” ball while a severe hail rating uses a 1.75” ball. There is also a very severe hail rating that utilizes a device to shoot an ice ball onto the roof system at a high rate of speed.
• Leak Testing. This roof test focuses on the seams of the roof system, a common source of roof leaks. A 6” diameter tube is centered under a seam of the roof system, with water standing or ponding on top. The purpose is to see if the seam holds or if the water drips through the tube.

Commercial Roof Testing Considerations

There are several variations and methodologies of commercial roof testing. Always look for accredited testing facilities like UL, ETC, Nemo, and PRI. Local building codes may require specific accreditations so be sure to pay attention. FM or Factory Mutual also has a certain set of approvals required.

Make sure to review testing for whatever is required for your area. For example, a roof system can have a high wind uplift rating but uses flammable adhesive, so the fire rating is low. Understand what is required for each test for your facility.

The entire roof assembly should be tested, meaning the deck, securements (adhesive or fasteners), insulation, base sheets, and membranes or topcoats. Individual physical properties are often tested on materials within the assembly through ASTM. Some codes require physical property testing for each material used, as well as roof assembly testing.