Testing of Facade in Buildings

Introduction

AAMI 501.2 and AAMI 502 water tests are considered as the most important on-site Quality Assurant facade tests in buildings. The façade of a building is its most visible and crucial component, providing both aesthetic appeal and protection from external elements. In Australia, the testing of facades for water penetration is governed by two key standards: AS 4284 and AS 4654. These standards outline the specific procedures and methods for testing water penetration resistance in different types of facades. In addition to these national standards, international standards such as AAMI 501.2 and AAMI 502 are also commonly used to evaluate the water resistance of building facades. In this blog, we will explore these standards in detail and their importance in ensuring the safety and longevity of building facades in Australia.

Testing of façade in Australia

Facade testing is an important aspect of building design and construction, as it helps to ensure the safety, performance, and compliance of building envelopes. In Australia, there are several types of facade testing that are commonly conducted to evaluate the performance of building facades. These include:

1. Air Infiltration Testing: Air infiltration testing measures the amount of air that leaks through the building envelope. This test is important because it helps to identify areas of the building envelope where air leakage occurs, which can affect energy efficiency, indoor air quality, and occupant comfort.
2. Water Penetration Testing: This test examines how well the building can withstand water infiltration, especially in cases of strong wind and rain. It helps to identify weak spots in the building envelope that could allow water to enter and cause damage to the building’s structure, finishes, and equipment.
3. Structural Testing: This test evaluates the strength and stiffness of building components like windows, doors, and curtain walls. Its purpose is to ensure that these components can withstand the various loads and forces they will face over their lifespan.
4. Acoustic Testing: This test measures the amount of sound that can penetrate through the building envelope. It is used to determine if the building envelope provides sufficient sound insulation and can reduce noise levels from external sources.
5. Fire Testing: Fire testing evaluates the fire resistance of building components, such as insulation, glazing, and cladding. The aim is to ensure that these components can prevent the spread of fire and protect the building’s occupants.

In Australia, facade testing is typically conducted in accordance with the relevant Australian Standards, such as AS 4284, AS 4654, AS 1530, AS/NZS 3837 and other international standards such as AAMA and ASTM E. Testing results are used to inform building design and construction, as well as compliance with building codes and regulations. In this post, we mainly focus on water penetration tests.

Water Penetration Tests:

Water penetration testing is a type of facade testing that assesses how well the building envelope can resist water infiltration in different scenarios, like wind-driven rain. This test is essential because water infiltration can cause damage to the building’s structure, finishes, and equipment, and lead to problems like mould growth, material deterioration, and reduced indoor air quality.

During water penetration testing, a calibrated water spray simulates the effects of wind-driven rain on a small section of the building envelope, such as a mock-up or representative facade section. The test may be conducted at different pressure differentials to simulate various wind speeds and directions. The test monitors and records any water that penetrates the building envelope.

The results of the test help evaluate the water resistance of the building envelope and identify any vulnerable areas. The results may also inform design and construction decisions, such as material selection and detailing, to enhance the water resistance of the building envelope.

In Australia, water penetration testing is typically conducted following relevant Australian Standards, like AS 4284 and AS 4654, and other international standards such as AAMA 501.2, AAMA 502, and ASTM E1105. These standards provide guidelines for conducting the test, interpreting the results, and specifying the equipment and procedures to be used.

Water Ingress Test as per AAMA

AAMA 501.2 Test

In Australia, a commonly used field test is the American Architectural Manufacturers Association AAMA – Quality Assurance and Diagnostic Water Leakage Field Check for installed windows, doors, skylights, shopfronts, curtain walls, and sloped glazing systems. Along with AAMA 502, AAMA 503, ASTM E1105, and other testing standards, AAMA 501.2 is used to identify water leakage in newly constructed commercial buildings. The purpose of this test is to provide a quality assurance and diagnostic method for checking the field water installation of storefronts, curtain walls, and sloped glazing systems. It should be noted that AAMA 501.2 is not a test for the design of the façade system, but rather a test for installation and trade.

A significant benefit of AAMA 501.2 is its ease of use and repeatability. The reason is that the equipment required by the AAMA 501.2 tests includes a specific nozzle that measures the water pressure. The procedure also dictates the required pressure and describes a specific procedure for applying the water to the façade.

AAMA 501.2 test is designed to simulate wind-driven rain and evaluates the ability of these building components to resist water infiltration under specific test conditions. The test involves subjecting the specimen to a controlled water spray from calibrated nozzles conducted at different pressure differentials to simulate different wind speeds and directions. The water spray is directed at the exterior surface of the specimen for a specified period of time, and any water that penetrates through the specimen is collected and measured.

The test also evaluates other factors, such as air leakage to determine if the specimen meets the requirements of the test standard.

It is crucial to understand that the spray rate for the AAMA 5.12 test should always be maintained at 30-35 PSI, and should never go below this pressure. However, the standard does permit a reduction in pressure, as long as it is not less than 25 PSI and is deemed acceptable by the specifier.

Here is a step-by-step overview of the test procedure:

1. Preparation: Before conducting the test, the specimen is installed in a test chamber or mock-up, according to the manufacturer’s instructions (AAMA 502 test only). The chamber or mock-up is equipped with calibrated nozzles, which are used to spray water at the specimen. For AAMA501.2 tests, random building envelopes are selected and prepared for the test (approximately 100 ft2 or 9.3 m2 area) without installing a pressurised chamber.
2. Water spray: The test begins by subjecting the specimen to a controlled water spray from calibrated nozzles. The spray is directed at the exterior surface of the specimen for a specified period of time, and any water that penetrates through the specimen is collected and measured.
3. Pressure Differentials: The test is conducted by varying the pressure differentials to simulate different wind speeds and directions. The pressure differentials are typically defined in the test standard and may be adjusted as per the specific needs of the project.
4. Evaluation: Once the test is completed, the quantity of water that penetrates through the sample is measured, and the outcomes are compared with the acceptance criteria specified in the test standard. Additionally, other factors, such as air leakage and structural performance, may also be assessed during the test (AAMA 502 test only) to determine if the sample meets the requirements of the test standard.
5. Reporting: The test results are usually documented in a formal test report, which includes information like the test procedure, test outcomes, acceptance criteria, and any observations or recommendations related to the test.

The 501.2 storefront test is useful when testing the perimeter and other sealants as well as seals and joints within the window product. 501.2 tests are not to be used on operable doors or windows. Nor is the standard applicable for testing the rating or specific water performance of a product. The 501.2 standard will refer to the AAMA 502 and 503 standards for this.

AAMA 502 Test

The AAMA 501.2 and AAMA 502 test standards are both used to evaluate the water penetration resistance of building components, but they differ in their specific applications and test procedures. It’s important to note that the AAMA 502 test standard also utilizes the ASTM E1105 test method which details specific test set-up and equipment requirements for the water penetration portion of the test and the ASTM E-783 test method which details test set-up and equipment requirements for the Air Infiltration portion of the test.
During AAMA 502 verification testing, an air test chamber is attached and sealed to the wall or roof construction in order to create a pressure differential across the entire area and to seal the perimeter. The testing needs to be performed and completed as soon as possible after the fenestration product is installed and before drywall or other interior finish wall/roof materials are installed. Once fenestration products are installed, adjusted, cleaned, and perimeter sealed, the fenestration products will be tested for air leakage resistance and water penetration resistance.

Australian Standard AS/NZ 4284

It is typical for façades to undergo weather tightness tests to comply with the requirements of the National Construction Code (NCC) and relevant Australian Codes of Practice before construction.

Australian Standard AS/NZS 4284 is a widely used standard for testing curtain wall façades, including panelised curtain wall systems. Its purpose is to evaluate the overall performance of the system and how the various façade components interact with each other. The Sirowet method, which originated from the Commonwealth Scientific and Industrial Research Organisation (CSIRO), is the basis for the original tests outlined in AS/NZ 4284. To conduct the tests according to AS/NZ 4284, a prototype must be constructed and the external side of the façade must be sealed to a test chamber. Water is then sprayed onto the façade at a predetermined rate to test its resistance to water penetration. This weathertightness test is widely recognized by engineers and contractors. A diagram in AS/NZ 4284 shows the pressure boxes used in the test.

In addition to the water penetration tests, AS/NZ 4284 also includes other tests. These are:

• Air infiltration;
• Seismic tests;
• Seismic test at serviceability limit state displacement which includes subsequent water penetration test;
• Building maintenance unit (BMU) test;
• Façade strength test at ultimate limit state;
• Seal degradation test.

Australian Standard AS 2047 for windows and doors

All windows and external glazed doors must meet the requirements of Australian Standard AS 2047 as per the NCC deemed-to-satisfy regulations. This standard aims to provide generic guidelines for the design and manufacture of windows and doors, with water penetration, operating force (for operable sashes), and air infiltration being the main concerns. The relevant testing standard for windows is Australian Standard AS 4420, which includes various tests such as water penetration, frame deflection, operating force, air infiltration, and ultimate strength tests. Participants of this course should note that most complaints regarding windows and doors are related to water penetration, followed by problems with the operation of operable sashes.

Prototype mock-up

As previously mentioned, compliance with the NCC can be achieved through a Performance Solution, a Deemed-to-Satisfy Solution, or a combination of both, backed up by one or more Assessment Methods. A widely used Assessment Method is the ‘verification method’, which involves constructing a mock-up of a façade system prototype and testing it for compliance.

The image above shows a prototype mock-up (PMU) of a façade, made for testing compliance with section FP1.4 of BCA Volume One and P2.2.2 of BCA Volume 2 of the NCC.

Conclusion

The facade of a building serves as its protective outer shell, guarding against external elements while contributing to its aesthetic appeal. With the growing concerns surrounding climate change and extreme weather events, the testing of facades for water penetration has become an essential aspect of ensuring building safety and longevity.

In Australia, the testing of facades is governed by key standards such as AS 4284 and AS 4654, which outline specific procedures and methods for evaluating water penetration resistance in different facade types. Additionally, international standards like AAMA 501.2 and AAMA 502 are also commonly employed to assess water resistance.

Facade testing encompasses various critical aspects, including air infiltration, water penetration, structural strength, acoustic insulation, and fire resistance. Each of these tests plays a vital role in identifying vulnerabilities in the building envelope, enabling proactive measures to mitigate potential risks.

Water penetration testing, in particular, examines how well the facade can withstand water infiltration during wind-driven rain scenarios. By subjecting a small section of the facade to a calibrated water spray, engineers can assess its water resistance and identify weak points that may lead to structural damage or compromised indoor air quality.

AAMA 501.2 and AAMA 502 are widely utilized for water penetration verification testing, focusing on storefronts, curtain walls, and sloped glazing systems. These tests simulate wind-driven rain to evaluate the ability of building components to resist water infiltration under specific conditions.

Australian Standard AS/NZS 4284 is commonly used for curtain wall facade testing, employing the Sirowet method to evaluate the overall performance of the system and the interaction of its components.

Windows and external glazed doors must adhere to Australian Standard AS 2047, which focuses on water penetration, operating force, and air infiltration concerns.

Mock-up testing, as part of the verification method, allows for compliance with the National Construction Code (NCC) through the construction and evaluation of a prototype facade system.

In conclusion, the testing of facades is a crucial step in ensuring the safety, performance, and compliance of modern buildings. By adhering to the relevant standards and conducting thorough testing procedures, architects, engineers, and construction professionals can create durable, resilient, and weather-resistant facades that contribute to the longevity and sustainability of the built environment.

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