Selecting the appropriate glazing for conservation rooflights involves considering various factors, including weather conditions, structural loads, and internal / external atmospheres. This guide helps you understand the glazing considerations for conservation rooflights.
Glazing considerations
Key considerations include the size of glass panes, design loadings, and the overall performance parameters desired.
Glass size
The size of glass panes influences the required thickness of the glazing unit, with a general rule that larger panes necessitate thicker units. Seeking advice from knowledgeable professionals is crucial to ensure proper selection.
Glass coating
Glass coatings play a significant role, offering improvements in thermal performance, solar reflectance, light transmission, UV protection, and more. However, these coatings may be limited by the appropriate glass thickness, requiring guidance from rooflight manufacturers.
Thermal performance
Thermal performance, measured in U-Values, reflects the heat transfer between a building and its surroundings. Advances in low-emissivity glazing technology have enhanced thermal insulation, with the use of low-e glass becoming mandatory in many cases. Triple Glazed Units (TGU) can further reduce U-Values, but considerations must be made for increased weight and structural loads.
Solar control
Solar control coatings help manage solar gain into properties, preventing rooms from becoming excessively hot during summer. This effective use of solar control glass can reduce the need for air-conditioning and blinds, leading to cost savings.
Furniture fading is often caused by heat, infrared light, and harmful UV rays. PVB laminated glass can virtually eliminate UV radiation, offering protection against fading.
Glazing safety
Safety considerations for glazed roofs involve impact resistance and fall prevention.
Robustness focuses on damage prevention, setting performance requirements for the upper pane of glass, while safety addresses fall prevention and glass retention for the lower pane.
Toughened glass may be necessary in certain instances, and its strength lies in its ability to break into small particles when shattered. However, the risk of spontaneous breakage due to Nickel Sulphide Inclusions (NSI) exists, and a risk assessment should be conducted to evaluate potential hazards.
Heat Soaking, a process where glass is heated to 250 degrees Celsius after tempering, can reduce the risk of NSI breakage by causing panels with impurities to shatter. Heat-soaked toughened glass has specific usage restrictions based on height and thickness.
Laminated glass, with its ability to remain in place when broken, is a suitable option for overhead glazing. A thorough risk assessment considering the probability of glass failure, the likelihood of falling glass, and the consequences of falling glass is essential for safe use in such situations.
Conclusion
Selecting the right rooflight glazing involves a nuanced approach, balancing performance parameters with aesthetic and budget considerations while prioritising safety and functionality.
There are so many choices and considerations when it comes to glazing for your conservation rooflight. It is often best to be guided by your rooflight manufacturer as to the most suitable glazing type for your installation.
