ASTM E331 and ASTM E1105: Testing Water Resistance of Exterior Walls

Raindrops test the water resistance of an exterior window, skyscrapers in the background
Raindrops Test The Water Resistance Of An Exterior Window Overlooking Skyscrapers

Water resistance is a critical performance factor for a building envelope, especially in climates where wet, wind-driven rain is a common condition. Keeping water out of wall assemblies is crucial for the long-term health of buildings and their occupants. As with other aspects of building envelope performance, there is a test for that. It is called ASTM E331.

ASTM E331 – Testing Water Resistance In The Laboratory

The full title of ASTM E331 explains its purpose: Standard test method for water penetration of exterior windows, skylights, doors, and curtain walls by uniform static air pressure difference. The test is applicable for testing water resistance of an entire curtain wall or a window, skylight or door alone.

Intended to simulate a realistic scenario, the test requires the construction of a specimen wall with all components to be tested at full size using the same details as in an actual wall assembly. This could include an air barrier or water-resistive barrier as part of the assembly.

The specimen is installed on one side of a sealed test chamber, which is equipped with a water spray grid with nozzles that spray water on the specimen uniformly at a minimum rate of 3.4 L/m2-min. The chamber also has a blower or compressed air system that provides a constant air flow at a fixed pressure. The idea is to create a pressure differential of 137 pascals (Pa), unless otherwise specified. For a skylight, the specimen should be angled as it would be in an actual building installation.

The specimen is then subjected to the water spray and air pressure for a period of 15 minutes. Test technicians observe the test specimen and record any and all points of water penetration on the inside face of the specimen.

ASTM E1105 – Testing Water Resistance In The Field

What about testing water resistance of a wall in the field? Obviously, the method defined in ASTM E331 would be difficult to replicate on site. That’s where ASTM E1105 comes in. It defines a standard test method for determining water penetration of installed curtain walls, windows, doors, and skylights in the field. The wall or fenestration is fitted with an apparatus that creates either uniform pressure or cyclic pressure on the inside surface. A calibrated spray rack with nozzles on the exterior surface sprays water at the installed wall assembly or fenestration at a rate of 3.4 L/m2-min. In this way, ASTM E1105 attempts to simulate the real-world conditions of wind-driven water, similar to the lab water penetration test method described in ASTM E331—with the added advantage of optionally using cyclic pressure, which may replicate conditions more realistically.

Contact A Local Air Barrier Specialist Today

Both ASTM E331 and ASTM E1105 can provide invaluable information on the water resistive performance of curtain walls and fenestrations – either beforehand in the lab or on the project site as construction is underway. Call your local air barrier specialists today at Atlas Supply. Our specialists will help you to select the optimal air barrier for your application and answer any installation questions you might have. Call now!

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Last Modified: May 28, 2019

8th Annual ABAA Conference & Trade Show

Attend the 8th Annual Air Barrier Association of America (ABAA)’s Conference and Trade Show, March 26-27, 2019 in Norfolk, Virginia to learn from some of the top minds in Building Science. Earn American Institute of Architects (AIA) continuing education units (CEUs) for attending.

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Last Modified: November 23, 2018

DOWSIL™ Case Study Cornish Commons – Seattle, Washington

Cornish Commons residence hall with unique rainscreen design - Seattle, WA
Cornish Commons residence hall with unique rainscreen design – Seattle, Washington

A premier college for the visual and performing arts, Cornish College of the Arts’ main campus is located in Seattle’s popular South Lake Union neighborhood, where the 20-story Cornish Commons opened in 2015.

The new residence hall and academic building includes a unique rainscreen design featuring 3/16-inch thick architectural aluminum cladding on cold-form framing. The innovative building design boasts thermal performance 40% better than required by current Seattle Building Code.

Cornish Commons’ Challenge

To achieve its ambitious thermal performance, the rainscreen design includes 2-inch, continuous R-8, exterior insulation to supplement the R-32 interior batt/cavity insulation. But that created additional challenges to be compliant with the Seattle Building Code, which dictates use of insulation outboard of the metal framing. The proposed design needed an air barrier with high permeability to ensure water vapor was not trapped in the wall cavity.

Additionally, staying on schedule – in spite of challenging Seattle weather conditions – was critical. Minimizing product incompatibility issues also was important.

Cornish Commons’ Solution

Ankrom Moisan Architects, Inc. selected the 100% silicone DOWSIL Silicone Air Barrier System to ensure enclosure airtightness performance, durability and compatibility.

When we learned about the option of a fluid-applied silicone air and water barrier, we realized that DOWSIL DefendAir 200 was ideal for our needs. Not only did the spray-applied product simplify installation and eliminate the need for traditional membrane materials, its high permeability ensured our design’s compliance with Seattle Building Code.

Eric Bressman, Architect, Ankrom Moisan Architects

Unitized Construction

To keep the Cornish Commons project on schedule, the design called for a combination of unitized rainscreen panels and traditional construction techniques. The use of unitized panels assembled off-site in a controlled manufacturing environment enabled continued productivity, regardless of weather.

An external cladding contractor’s licensed use of a patented, universal joint system (U.S. Patent 8,943,773) facilitated construction of the unitized panels. This system is designed with interlocking joints that mitigate improper installation conditions that increase the risk of failure.ß The joint system relies on DOWSIL sealants for enhanced performance.

The panels used DOWSIL silicones exclusively: DOWSIL DefendAir 200 as an air barrier and DOWSIL 791 Silicone Weatherproofing Sealant for unit sealing. The quick cure capability of the DOWSIL products helped keep unit assembly on schedule. The unitized rainscreen system was used from the third floor to the 20th floor – using 30 units per floor – with approximately 50,000 square feet protected by the DOWSIL Silicone Air Barrier System.

All-Weather Installation

Construction on-site continued into late fall, due in part to the low-temperature installation capability of DOWSIL DefendAir 200, which can be applied at temperatures as low as 20°F (-6°C).

The ability to use spray-applied product was much easier, said Jerry Jensen, Project Manager. Its cold-weather ability allowed us to continue construction into inclement fall weather.

In addition to the unitized rainscreen panels, on-site work totaling nearly 8,000 square feet used the DOWSIL Silicone Air Barrier System on the first and second floors.

Confidently Build A Better Barrier – Simple. Compatible. Silicones.

Because it is not uncommon to face challenges with varying interfacing construction materials, having a compatible all-silicone solution from Dow was appreciated and advantageous.

Having exclusively silicone products ensured compatibility. Rather than an ‘origami’ of incompatible materials around openings, having all-silicone materials simplified construction and eliminated uncertainty. It is straightforward. We can get answers from a single, trusted manufacturer, without unproductive back-and-forth exchanges with multiple suppliers. It’s helpful to have the continuity and support – and the confidence of warranty protection – from [Dow.]

Jerry Jensen, Project Manager, external cladding contractor

Additionally, the all-silicone compatibility of the DOWSIL Silicone Air Barrier System allowed materials to be applied in any order, eliminating sequencing delays and expenses.

Learn More About DOWSIL Silicone Air Barrier System

Dow High Performance Building solutions include proven and innovative materials for structural and protective glazing, weatherproofing, insulating glass, high-efficiency insulation, and window and door fabrication. Learn more about the DOWSIL Silicone Air Barrier System and other High Performance Building solutions from Dow.

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Last Modified: May 24, 2019