Technical Advice | Useful Information about Architectural Glazing

Weather Performance and Testing for Architectural Glazing

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Rebecca Clayton

Written by Rebecca Clayton

Edited by Dan Finnegan

Fact-checked by Michal Piekarewicz

Aug 19, 2026

Last verified: Aug 19, 2026

Next review: Aug 19, 2026

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Architectural glazing is constantly having to evolve and develop to adhere to the most stringent Building Regulations within the UK. This has lead to weather performance testing exceeding the limits of the harshest driving rain to ensure that it can perform under volatile and unpredictable climates.  

 

Important factors of weather performance.  

When weather performance is mentioned during glazing specification  it can be easy to overlook how in-depth and how vast the term ‘weather performance’ actually is.  

The main categories of weather performance are:  

  • Wind load and resistance  
  • Thermal performance  
  • Air permeability 
  • Water resistance  

Hurricane resistance is also a factor to consider if that applies to the project area* 

 Water tightness testing in glazing systems

Wind Load and resistance 

The phrase "wind loading" describes the amount of wind pressure that glass must be able to withstand. There are several variables to consider when calculating wind loads for architectural glazing projects, such as the height, shape, proximity to other structures, and geography. As these forces all exert pressure on the building, it is also necessary to consider the local wind speeds and gust durations. 

Learn more about wind loads and resistance. 

Thermal Performance  

Thermal performance is a key component of contemporary building design that is becoming more and more significant. This holds true for the glazing as well as the rest of the building envelope.  

The most important consideration when selecting the best glazing for home or commercial buildings is  the thermal performance. In order to ensure comfortable living and working temperatures, it is crucial to have an optimal temperature in the interior spaces. 

Read more about Glazing thermal performance updated Building Regulations Approved Document L  

Air Permeability  

The amount of air that can pass through a window or door system when it is closed is referred to as air permeability. Testing for air permeability relies on the engineering, manufacturing, and sealing quality of the system to guarantee that all opening segments fit together tightly and completely to prevent as much airflow through the system as feasible. 

Ensuring minimum wind/breeze intrusion is important for the comfort of the interior areas. It is also crucial for environmental elements to limit the system's energy flow from the inside to the exterior. 

See our article Building Regulations Part L1 | Architectural glazing to exisiting dwellings

Water resistance 

Water resistance goes hand in hand with the previous factors of glazing weather performance. Water resistance for glazing is commonly an overlooked factor which leads to a great deal of issues such as water ingress, rusting and general system failure.  

 

How is weather performance tested?  

Weather performance for glazing can be tested in several ways. Here at IQ we have our glazing tested in a climate simulator which pushes our systems to their limits. During the simulation all types of products will have to overcome heavy wind simulations and even hurricane situations where large objects are hurled at the glazing with great force.  

Of course, glazing systems have to perform thermally as well. This is again tested in a simulation where great deals of hot and cold elements are used to properly understand which U values the glazing achieves.  

 

Why is weather performance and testing for architectural glazing important?  

When specifying systems such as our ultra slim framed sliding doors or Invisio structural glazing naturally the look and aesthetic is of upmost importance to architects and end users.  

While it is great to have a modern and sleek system installed, if the weather performance of the system has been overlooked it could cause costly situations such as loss of thermal performance throughout a building, water ingress and heavy condensation.  

 Ultra slim framed floor to ceiling sliding glass doors connects the cliffside home to the Cornish coastal surroundings.

How can you ensure that your IQ system will perform to the highest standards?  

At IQ Glass, we always pride ourselves on providing accurate and tested data with regards to our systems weather performance and testing. Weather performance and testing for architectural glazing is something that we do not overlook, and with our in house design team we are constantly improving our products and their performance.  

We provide data sheets which cover all aspects of how a specific system will perform in a variety of environments.  

 

If you have any questions regarding weather performance and testing for architectural glazing or would like to request our data sheets, Contact the team today