Glint and Glare Assessment

Question: What is a Glint and Glare Assessment?

Answer: A Glint and Glare Assessment evaluates the potential for reflected sunlight from a proposed development to affect nearby receptors. Glint is a momentary flash of reflected light, while glare is a continuous reflection. Assessments are most commonly required for solar photovoltaic installations but are also relevant to highly glazed or metal-clad buildings.

The assessment identifies receptors such as dwellings, roads, railways, airports and aircraft flight paths, calculates when and where reflections could occur, and determines whether the effect is likely to be significant or requires mitigation.

Question: When is a Glint and Glare Assessment required for planning?

Answer: Assessments are commonly required for:

• Ground-mounted solar farms
• Roof-mounted and canopy solar PV near roads, railways or homes
• Solar installations within safeguarding zones of airports and aerodromes
• Highly reflective façades, glazed buildings and metal-clad structures near roads or airports
• Developments near railway signals or level crossings

Local Planning Authorities, National Highways, Network Rail, the Civil Aviation Authority and airport operators may all request an assessment as statutory or non-statutory consultees.

Question: What guidance is used for Glint and Glare Assessments?

Answer: There is no single UK statutory standard, but assessments generally follow:

• Federal Aviation Administration (FAA) guidance and the Solar Glare Hazard Analysis Tool (SGHAT) methodology
• Civil Aviation Authority CAP 738 and aerodrome safeguarding guidance
• Pager Power guidance on glint and glare from solar PV
• National Highways and Network Rail requirements for reflections affecting drivers and train operators
• Institute of Lighting Professionals guidance where relevant

Results for aviation receptors are usually expressed using FAA ocular impact categories.

Question: How is glint and glare modelled?

Answer: Geometric modelling calculates the position of the sun throughout the year and the angles at which sunlight would reflect from the panels or façade towards each receptor. The model considers panel tilt, orientation, tracking, receptor location and height, and screening from buildings, terrain and vegetation. Outputs show the dates, times and duration of potential reflections and the intensity of the effect at each receptor.

Question: What are the effects of glint and glare on aviation?

Answer: Reflections from solar panels can affect pilots on approach, air traffic controllers in control towers and airport operations. The FAA methodology classifies reflections as no glare, low potential for temporary after-image, or high potential for temporary after-image. Airports typically require assessments for solar installations within a defined distance and may object to installations that create a high impact on final approach paths or the tower.

Question: What mitigation can reduce glint and glare?

Answer: Mitigation options include reorienting or re-tilting panels, using anti-reflective coated panels, screening with planting, fencing or bunding, adjusting the layout to avoid critical receptors and, for buildings, specifying low-reflectance glazing and cladding. The assessment identifies which measures are needed and demonstrates their effectiveness.

Question: Why choose Syntegra Group for a Glint and Glare Assessment?

Answer: Syntegra Group prepares Glint and Glare Assessments for solar PV installations and reflective buildings across the UK, supporting planning applications, discharge of conditions and consultations with airports, National Highways and Network Rail. Our assessments use recognised geometric modelling methods and present results clearly for planning officers and aviation stakeholders.

As designers of solar PV and building services systems, we can advise on layout and specification changes that resolve glare issues without unduly compromising the performance of the installation.