Archive for June, 2012

Trial by fire

The trial gets fully under way as a technician moves a gas-powered flame bar up to the wall assembly mock-up exterior. A fire in an oven has already been moved up to the back of the mock-up, simulating an interior fire.

I’m proud of the fact that PROSOCO R-GUARD Cat 5, our primary air-and-waterproof barrier, keeps water out of structural walls, rigid sheathing and CMU back-up in conditions from a mild Spring day to a category-5 hurricane.

Mild to wild, as we say.

Now we get to add a new bullet point to Cat 5’s resume — fire-resistance.

Here’s the story. They’re anticipating using Cat 5 on an EIFS project in the Caribbean. They get hurricanes and tropical storms there, along with rain almost every day, so Cat 5 is a good choice.

But if your wall assembly has combustible components like this Caribbean project, the International Building Code says it has to be tested according to NFPA 285–Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load-Bearing Wall Assemblies Containing Combustible Components.

NFPA stands for National Fire Protection Association.

Combustible components in this assembly include exterior foam plastic continuous insulation — 2-foot by 4-foot expanded polystyrene panels, 4 inches thick. Cat 5, like all water-resistive barriers on the market is also considered combustible — even though it’s similar to silicon sealants and chemically inert when cured. So the wall assembly needs to be tested.

It’s important to understand that NFPA 285 isn’t a test of Cat 5 — or any individual component in the assembly. It’s a test of the wall assembly itself.

Individual testing under ASTM E 84-12
Tested individually under ASTM E 84-12 Standard Method of Test for Surface Burning Characteristics of Building Materials in April, Cat 5 proved to be a Class A building material under the NFPA’s Life Safety Code.

Class A is defined as “Can withstand severe exposure from fire originating from a source outside the building.” Clay brick is another example of a Class A building material.

On the zero-to-100 Flame Spread Index where zero is fiber-reinforced cement board, grade II; and 100 is red oak flooring, Cat 5 rated 10.6. On the zero-to-100 Smoke Developed Index, Cat 5 tested at 2.6

The test assembly
An independent third-party test facility conducted NFPA 285 on the wall assembly incorporating Cat 5 June 14. Representatives of the manufacturers whose components went into the walls built the mock-up to the same specs as the Caribbean project. Here’s some photos of the test assembly going up.

Shawn Derosier applies CAT 5 primary air & water barrier over Densglass.

Next, the expanded polystyrene continuous foam plastic exterior insulation goes on over the Cat 5.

The EIFS finish coat goes on.

Time for fire
With the mock-up constructed, it’s time for the fire.

NFPA 285 tests the wall assembly — a two-story mock-up with a first floor window — to measure whether or not the fire spreads beyond an acceptable distance either horizontally or vertically on the exterior, or through the core of the wall, where the combustible materials are located.

The 30-minute test scenario is that there’s a fire inside, shooting a fire plume out of the window.

The inside fire is simulated by backing the mock-up against a test oven lit with a roaring fire.

The interior fire is simulated by backing the mock-up to this test oven, which will be filled by real, live flames.

Here’s NFPA 285 under way.

An inspector tears away the burnt surface to see how the foam plastic insulation and Cat 5 beneath it fared.

Here’s the damage revealed. though much of the foam plastic melted and ran during the 30-minute burn, it doesn’t appear to have actually ignited.

Here’s a closer look. It appears that a bit of the Cat 5 was scorched off the window header where the flames made direct contact, but was not impacted elsewhere.

Along with dimensions written on the side of the test panel, the mock-up also contained thermocouples for measuring heat. I’m told they indicated 1600 degrees — more than double the melting point of lead.

Result of the testing? The wall assembly, including Cat 5, faced trial by fire — and passed.

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A participant in the Portland BEC Technical Symposium 2012 contemplates three of the four mock-ups to be tested, including our FastFlash mock up (right).

So there’s four 6 x 8-foot wall assembly mock-ups. Each has a window and several through-wall penetrations. They’re identical except for the air barrier coverings. One is a fluid-applied system — that’s our own FastFlash. It’s got seams, joints and gaps sealed with Joint & Seam Filler; a rough opening for the window flashed with FastFlash; the main wall covered in Cat 5; and the window frame sealed with Air Dam.

The other three mock-ups included a peel and stick membrane air barrier, a mechanically fastened air barrier and a bitumen membrane. They were all on display at Portland BEC’s (Building Enclosure Council) 2012 Technical Symposium, June 4, in Portland, Ore. Those products belonged to big names who you’d definitely recognize, and all of whom, along with BEI/PROSOCO sponsored or supported the event.

The day-long program featured recent national and international research focusing on air barriers in existing and new building enclosure design. The symposium presented academic research complemented with real-world applications and case studies.

Sessions and speakers included some of the leading experts and practitioners of air barrier and building envelope science, including Laverne Dalgleish, executive director of the Air Barrier Association of America.

The reason I’m writing you about it is that the symposium included an independent test for air-tightness of the four air barrier mock-ups. And I love the fact that they conducted the test in an objective, highly technical environment in front of some of the industry’s best and brightest engineers, contractors and architects.

They used ASTM E783 to test the mock-ups.

This method, according to the ASTM website, “is a standard procedure for determining the air leakage characteristics of installed exterior windows and doors under specified static air pressure differences.”

Short version– PROSOCO R-GUARD FastFlash kicked butt.

Test results. Note the disparity in the amount of air leakage between the top entry (FastFlash) and the bottom three other types of air barriers. Tests were done independently at the Portland Building Enclosure Council’s 2012 Technical Symposium.

The test simulated wind loads of about 25 mph (75 Pa WIN-ISO) and about 50 mph (299 Pa WIN-ISO). Since the testing equipment couldn’t measure down to zero leakage, the results had to show the minimum it could measure, which is why the FastFlash results show any leakage at all, says BEI’s Tom Schneider, one of the participants.

“This was one of the proudest moments of my career,” he said. “It was great to be part of such an accomplished group of building envelope professionals, and even greater to show them undeniable proof of the capabilities of the products we developed.”

Box of water, anyone? This cardboard box is lined with FastFlash waterproof (but vapor permeable) liquid flashing for rough openings. The box, filled with water, sat all day at BEI/PROSOCO’s exhibit at the Portland BEC Technical Symposium without leaking a drop. As I write 10 days later, the box is still filled with water, not leaking, and on display at BEI’s Clackamas, Ore., facility. ~ photos courtesy of Tom Schneider

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