Egress windows are crucial for the safety and well-being of occupants in any residential building. They provide an accessible escape route in case of emergencies, like fires or gas leaks. However, to serve their purpose effectively, egress windows must adhere to specific size requirements set by local building codes. In this article, we will explore the steps on how to calculate egress window size and important considerations to keep in mind.

Step-By-Step Calculation

1. Understand local building codes: First, familiarize yourself with the local regulations governing egress window sizes, as these may vary depending on your jurisdiction. Consulting your homeowner’s association or contacting your local building department is a good starting point.

2. Measure window height: Building codes typically require that the bottom of the egress window’s opening be a certain distance off the floor—usually not exceeding 44 inches (1118 mm). Make sure you factor this requirement into your calculation.

3. Determine clear opening width: The egress window must have a minimum unobstructed area for proper egress or escape when fully open. According to most building codes, the minimum clear width should be no less than 20 inches (508 mm). Remember that this measurement refers to the actual opening space and not the frame or additional mechanisms.

4. Determine clear opening height: Similarly, most building codes also mandate a minimum clear opening height of at least 24 inches (610 mm). Keep in mind that adjustments may be necessary due to window sash interference.

5. Calculate net clear opening area: Multiply the clear opening width by height to obtain the net clear opening area in square inches. Most jurisdictions require a minimum net clear opening area of 5.7 square feet (0.53 square meters) or 820 square inches for grade-level windows and 5 square feet (0.46 square meters) or 720 square inches for windows located above the ground floor.

6. Compare actual window dimensions: Once you’ve calculated the net clear opening area, compare it to the dimensions of your egress window options. Ensure the selected model meets or exceeds the minimum requirements of your local building code.

Important Considerations

1. Access to window wells: If the egress window is located below ground level, ensure there is enough space for an occupant to safely exit and enter through a window well. Window wells should be at least 9 square feet (0.84 square meters) in area and allow a minimum horizontal projection of 36 inches (914 mm).

2. Window operation: Egress windows must be operable from inside without the use of any tools, keys, or additional force.

3. Bedroom requirements: Each bedroom in a residential property typically needs its own egress window—a vital consideration when planning new constructions or remodeling existing properties.

Conclusion

Calculating egress window size is critical for ensuring safety in residential constructions. Familiarizing yourself with local building codes and following these step-by-step guidelines will help ensure your egress windows meet all necessary requirements for proper emergency escape and rescue routes. Additionally, remember to keep crucial factors like access to window wells and multiple bedrooms in mind when planning various living spaces within the property.