RAS Engineering is a professional engineering company serving building managers and owners by providing advice, oversight restoration, and testing to ensure that all components of a build’s exterior and structure meet the standards necessary to provide quality durability and safe protection against the elements.
Jalousie Windows: Damage Assessment and Performance Evaluation
Jalousie windows, known for their horizontal panels (louvers) made of glass, metal, or wood, are designed to tilt open and control airflow. While these windows provide excellent ventilation, they are often more vulnerable to damage, especially in regions with extreme weather conditions like high winds or hurricanes. Assessing the condition and performance of jalousie windows is essential for determining their future usability and resilience against environmental forces.
A Level 1 assessment provides an initial, nondestructive evaluation of jalousie windows, allowing property owners or managers to gather essential data regarding their current condition. This blog discusses the process of assessing jalousie windows, the need for potential follow-up tests, and the importance of a thorough report to summarize findings.
The Level 1 Assessment Process
A Level 1 assessment for jalousie windows involves reviewing available records, interviewing occupants, and conducting a site inspection to document current conditions. Once the assessment is completed, a detailed report should summarize all tasks performed, any missing or assumed information, and findings that could indicate potential issues. Here’s a breakdown of the key components involved:
Key Steps in a Level 1 Assessment:
Review of Project and Repair Documents:
Collect and review historical documents to gather information about the original installation and any subsequent repairs. This helps establish the age of the windows and the materials used.
Site Inspection:
A physical inspection of the jalousie windows is crucial to identify visible signs of damage or deterioration. The framing type, material condition, louvers, and anchor points should be closely examined. Jalousie windows often feature thin glass or lightweight materials that can deteriorate over time, especially when exposed to heavy rain and wind.
Photographic Documentation:
During the site inspection, it’s essential to document all observations with detailed photographs. Clear captions and directional arrows on the photos can help highlight specific areas of concern, such as damaged louvers or weakened frame joints.
Manufacturer and Performance Data:
If possible, identify the window manufacturer and gather any performance data, such as resistance to wind pressure or water leakage. In many cases, this information may be unavailable, especially for older installations, but research and field observations can help make reasonable assumptions.
Occupant Interviews:
Speaking with building occupants can offer insights into the service history of the jalousie windows, including any performance problems like drafts or water intrusion. Focus on gathering factual data rather than subjective opinions.
Summarizing Findings:
The final report should include a detailed description of the methodology used, the site inspection findings, the materials reviewed, and any performance data obtained. The report should conclude with recommendations for further assessment, if necessary.
When to Recommend a Level 2 Assessment
A Level 2 assessment is recommended in cases where a more thorough analysis is needed. This is especially important when:
The Level 1 assessment reveals that the windows are nearing the end of their useful service life, particularly in regions where the basic wind speed exceeds 120 mph.
Critical information was not obtained during the Level 1 assessment.
Assumptions made during the Level 1 assessment need to be confirmed.
The Level 2 assessment involves more detailed field testing, potentially destructive analysis, and theoretical calculations to provide a comprehensive evaluation of the jalousie windows.
Field Testing and Theoretical Analysis in a Level 2 Assessment
During a Level 2 assessment, specialized testing methods are employed to verify the performance of the windows under real-world conditions. These tests help confirm whether the windows can withstand environmental stresses, particularly wind-driven rain and air infiltration. Some key tests include:
Water Infiltration Testing:
ASTM E1105-00 is the standard test for determining water penetration in windows, doors, and curtain walls. This test simulates wind-driven rain by applying water to the exterior face of the windows while creating a pressure differential inside the building. The test is designed to mimic real-world conditions and is critical for predicting how well the jalousie windows can prevent water leakage during storms.
Air Infiltration Testing:
ASTM E783-02(2018) is used to measure air leakage through installed windows. High air infiltration rates could signal that the windows are no longer sealing properly, which may indicate the need for repairs or replacement.
Partial Disassembly:
Sometimes, disassembling part of the window assembly allows inspectors to access concealed conditions, such as hidden anchors or framing joints. Observing these areas can help determine the overall condition of the assembly and whether it is performing as intended.
Anchor and Fastener Analysis:
The effectiveness of the window's anchors and fasteners is a critical factor in its performance. Over time, these components can corrode or weaken, especially in coastal or high-humidity environments. A detailed analysis of anchor substrates is essential to predict the future performance of the window system.
Theoretical Engineering Analysis:
If specific performance data are not available from the manufacturer, theoretical calculations can help estimate the windows' performance under wind loads. These calculations are based on measurements taken in the field and include framing dimensions, glass type, and the condition of anchors.
Reporting Level 2 Assessment Findings
The Level 2 assessment report should provide a thorough overview of all additional investigations and tests performed. The report should include:
A detailed summary of field water infiltration test results, with full test reports attached.
Photographs and descriptions of any partial disassembly or removed assemblies.
Theoretical calculations, if performed, with full details attached as an exhibit.
A summary of combined findings from both the Level 1 and Level 2 assessments, along with a prediction of future performance and recommendations for repairs or replacements.
Conclusion
Jalousie windows can offer excellent ventilation and aesthetic appeal, but they require careful evaluation to ensure they can withstand environmental stresses, particularly in regions prone to high winds. A thorough Level 1 assessment provides an initial overview of their condition, while a Level 2 assessment delves deeper into performance testing and analysis. By conducting these assessments and documenting the findings comprehensively, building owners can make informed decisions on the maintenance and potential replacement of jalousie windows to enhance the longevity and safety of the building envelope.