Comprehensive Analysis of Solar Shading Devices: Materials, Fire Safety, and Regulatory Compliance in the Context of Welsh Building Regulations 2025

Abstract

Solar shading devices represent a critical component in contemporary architectural design, primarily lauded for their efficacy in optimizing building energy performance and elevating occupant comfort through the strategic management of solar heat gain. However, their increasing prevalence, particularly when incorporating combustible materials, introduces a complex layer of fire safety considerations that demand rigorous evaluation. This comprehensive research report meticulously examines the diverse typologies of solar shading systems, the extensive array of materials commonly employed in their fabrication, and their inherent contributions to potential fire risk scenarios. A central focus is placed on the imperative design and material considerations necessary to ensure strict compliance with the updated Welsh Building Regulations 2025. Furthermore, the study critically analyzes applicable exemptions stipulated within these regulations, offering robust recommendations for best practices in the holistic design, material selection, and implementation of solar shading devices to reconcile energy efficiency ambitions with paramount fire safety objectives.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

1. Introduction

The imperative to construct buildings that are both energy-efficient and conducive to occupant well-being has propelled the integration of solar shading devices into mainstream architectural practice. These elements, encompassing a spectrum from fixed brise soleil to dynamic retractable awnings, operate on the fundamental principle of intercepting or redirecting solar radiation before it penetrates the building envelope. By effectively mitigating direct solar heat gain, they significantly reduce cooling loads, thereby lowering energy consumption, minimizing peak electricity demand, and enhancing indoor thermal comfort, especially during warmer periods [1]. This symbiotic relationship between architectural aesthetics and functional performance has cemented their status as indispensable features in sustainable building design across various climates and building typologies.

Despite their undeniable benefits, the proliferation of solar shading devices, particularly those fabricated from certain materials, has concurrently necessitated a critical re-evaluation of fire safety protocols within the built environment. The tragic events of the Grenfell Tower fire in 2017 served as a stark global catalyst, profoundly influencing building safety regulations worldwide and underscoring the catastrophic consequences of combustible materials within external wall systems [2]. In the aftermath, legislative bodies have progressively tightened regulations concerning facade materials, expanding their scope to encompass all elements attached to the external walls of buildings that could contribute to fire spread.

In Wales, this heightened awareness and regulatory evolution have culminated in the introduction of significant amendments to the Building Regulations, specifically the Welsh Building Regulations 2025. These amendments are pivotal, as they explicitly categorize solar shading devices under the definition of a ‘specified attachment’ [3]. This designation is not merely a bureaucratic reclassification; it represents a formal acknowledgement by the regulatory authority of both the energy performance benefits and the potential, often overlooked, fire risks associated with these elements. Consequently, solar shading devices are now subjected to stringent fire performance requirements, aligning their safety standards with other critical components of the external building envelope. This report undertakes a comprehensive analysis of solar shading devices, meticulously examining material selection, delineating their fire safety implications, and providing actionable guidance for ensuring full compliance with the updated Welsh regulatory framework, thereby fostering a safer and more sustainable built environment.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

2. Types of Solar Shading Devices

Solar shading devices exhibit remarkable diversity in their design, operational characteristics, and integration strategies within building facades. Their categorization is typically based on their fixed or adjustable nature, their proximity to the building envelope, and their primary mechanism of solar control. Understanding these distinctions is crucial for assessing their energy performance, aesthetic impact, and critically, their fire safety implications.

2.1 Fixed Shading Devices

Fixed shading devices are characterized by their permanent installation and immutable configuration. Once installed, they offer consistent shading performance based on their geometry and orientation relative to the sun’s path. While lacking adaptability to dynamic solar conditions or occupant preferences, their simplicity, durability, and often lower maintenance requirements make them an attractive choice for many architectural applications.

• Brise Soleil: French for ‘sun breaker,’ brise soleil are perhaps the most iconic form of fixed shading. They consist of horizontal or vertical blades, fins, or louvers strategically positioned to block high-angle summer sun while potentially allowing lower-angle winter sun to penetrate. They can be integrated directly into the facade structure or stand as independent architectural elements. Materials commonly include aluminum, steel, timber, or concrete. Their effectiveness is highly dependent on precise orientation and dimensioning, which requires a detailed sun path analysis during the design phase. From a fire safety perspective, their fixed nature means the materials are constantly exposed, and their structural components are critical.

• Louvers: While often part of a brise soleil system, louvers can also function as standalone fixed shading elements. They comprise an array of angled slats designed to control light and airflow. Fixed louvers are typically employed where a consistent level of shading and ventilation is desired. They can be horizontal, vertical, or even angled to optimize performance for specific facade orientations. Common materials include aluminum, steel, timber, and sometimes robust plastics. The spacing and angle of the slats are critical design parameters. Their fire risk is primarily linked to the combustibility of the louver material and their structural fixings.

• Overhangs and Fins: These are integral architectural features extending from the building facade. Overhangs typically shade windows from above, most effective for south-facing facades during midday sun. Vertical fins, on the other hand, are more effective for east and west facades, mitigating low-angle sun exposure. They can be made from concrete, metal, or masonry, often forming part of the primary structural or facade system. Due to their integration, their fire performance is often considered part of the overall facade assembly.

• Pergolas and Canopies: While often considered landscape elements, pergolas, when attached to buildings, can serve as effective overhead shading, particularly for ground-floor fenestration or outdoor spaces adjacent to the building. They typically feature an open framework of beams and rafters, sometimes covered with climbing vegetation (e.g., vines) or more permanent shading elements like fabric sails or fixed slats. Canopies are generally more robust and provide a solid or semi-solid overhead covering, extending outwards from the facade. The materials used, especially timber in pergolas or certain fabrics/plastics in canopies, introduce specific fire risks, which are compounded if they are close to the main building structure or fire escape routes.

2.2 Adjustable Shading Devices

Adjustable shading devices offer superior flexibility, allowing occupants or building management systems to dynamically respond to changing solar conditions, varying daylight requirements, and personal preferences. This adaptability maximizes energy savings and comfort throughout the day and across seasons, but often involves more complex mechanical systems and control mechanisms.

• Retractable Awnings: These typically consist of a fabric covering stretched over a frame that can be extended or retracted. They are particularly popular for residential applications, retail storefronts, and outdoor dining areas. Awnings can be manually operated or motorized, often integrated with sensors that detect wind speed or sun intensity. The primary shading element is the fabric, which can range from weather-resistant canvas to specialized solar control textiles. The framework is commonly aluminum or steel. Fire safety concerns with awnings are predominantly related to the combustibility of the fabric and the proximity of the retracted awning mechanism to combustible facade elements or openings.

• Operable Louvers: Unlike their fixed counterparts, operable louvers allow for dynamic adjustment of the slat angle. They can be manually cranked, electrically motorized, or integrated into sophisticated building management systems (BMS) for automated control. This enables precise regulation of daylighting, glare, solar heat gain, and even privacy. They are often larger scale than internal blinds and are external to the window, offering superior thermal performance. Materials include aluminum, steel, and treated timber. The fire risk here is not only the material combustibility but also the potential for failure of operating mechanisms in a fire, leaving them in a position that could hinder egress or promote fire spread.

• Roller Shutters and Blinds (External): While internal blinds are ubiquitous, external roller shutters and blinds offer a more effective barrier against solar heat and glare before it enters the glass. They typically consist of horizontal slats or a continuous fabric screen that can be rolled up or down. Often used for security purposes as well, they can also provide significant thermal insulation. Materials range from aluminum or steel for shutters to specialized performance fabrics for external blinds. Their controlled deployment and retraction are key features. Fire safety considerations include the combustibility of the slat material or fabric, especially when fully deployed and close to window openings.

2.3 Integrated Shading Devices

Integrated shading devices are seamlessly incorporated into the building’s architecture, often serving dual roles as aesthetic features and functional shading elements. Their design is inherently intertwined with the facade’s overall composition.

• Solar Screens/Mesh Screens: These are typically fine mesh materials installed over windows or curtain wall systems. They are designed to block a significant portion of solar radiation while maintaining outward visibility and allowing diffused light to enter. The mesh structure can be made from various materials, including fiberglass, polyester, or specialized metal weaves, often coated for durability and UV resistance. They are typically fixed but can sometimes be integrated into roller mechanisms. Fire concerns relate to the flammability of the mesh material and its contribution to external surface fire spread.

• Perforated Panels: These panels, made from metal (aluminum, steel) or sometimes composite materials, feature an array of perforations that allow for controlled light transmission and views while providing solar shading. The size, shape, and density of the perforations can be customized to optimize shading performance and aesthetic impact. They are often used as decorative facade elements in addition to their functional role. The fire performance is directly dependent on the base material and any coatings applied.

• Double-Skin Facades with Integrated Shading: In a double-skin facade system, an outer glazed or perforated layer is separated from the inner building facade by an air cavity, within which shading devices (often operable louvers or blinds) are integrated. This provides a highly controlled environment for solar management, natural ventilation, and acoustic performance. While the primary facade elements are typically non-combustible glass and metal, the integrated shading devices within the cavity, if made from combustible materials, pose a significant fire risk, particularly due to the chimney effect that can be created within the cavity during a fire [4]. This complexity requires meticulous fire engineering design.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

3. Materials Used in Solar Shading Devices

The choice of material for solar shading devices is a multi-faceted decision, influencing not only their aesthetic appeal, structural integrity, and durability but critically, their performance in a fire scenario. The Welsh Building Regulations 2025 place significant emphasis on material combustibility, necessitating a thorough understanding of the fire characteristics of commonly used substances.

3.1 Metals

Metals are a predominant choice for solar shading due to their inherent strength, durability, and often, non-combustible nature. However, specific treatments and assembly methods can influence their overall fire performance.

• Aluminum: This lightweight, corrosion-resistant metal is highly favored for louvers, brise soleil, frames for awnings, and perforated panels. Its low density facilitates complex designs and reduces structural loads on the building. Aluminum exhibits excellent thermal conductivity, which can be both an advantage (dissipating heat) and a disadvantage (conducting heat into the building). Critically, aluminum is classified as non-combustible. However, it can melt at relatively low temperatures (around 660°C), which, while not contributing to fuel, can lead to structural collapse of the shading device in a severe fire, potentially impeding firefighter access or causing secondary damage. Surface treatments, such as anodizing or powder coating, generally have negligible impact on the overall fire classification if applied thinly, but thicker polymer coatings could introduce minor combustible elements [5].

• Steel: Offering superior strength and stiffness compared to aluminum, steel is suitable for larger, heavier shading structures or where higher structural demands are present. It is heavier and requires protective coatings (e.g., galvanizing, paint) to prevent corrosion. Like aluminum, steel is fundamentally non-combustible. However, its structural integrity can be compromised at elevated temperatures (typically above 500-600°C), leading to a significant reduction in strength and potential collapse. Fire protection measures for steel, such as intumescent coatings, are more commonly applied to primary structural elements rather than shading devices, but their consideration for critical shading supports could be warranted in specific high-risk scenarios.

3.2 Wood

Wood, or timber, is valued for its natural aesthetic, renewable character, and biophilic qualities, making it a popular choice for pergolas, louvers, and brise soleil. However, its inherent combustibility presents a significant fire safety challenge.

• Timber: Untreated timber is a combustible material. It contributes fuel to a fire, can char, ignite, and propagate flames. The rate of charring and flame spread varies significantly depending on the timber species, density, and thickness. Softwoods generally burn faster than dense hardwoods. To mitigate this risk, timber used in external applications, particularly in multi-story buildings, often requires treatment with fire retardants. These treatments, which can be surface coatings or pressure impregnations, work by either forming a char layer that insulates the underlying wood, releasing non-combustible gases, or reducing the spread of flame. The effectiveness and durability of these treatments must be certified to relevant fire performance standards (e.g., Euroclass B or C, EN 13501-1 [6]). Regular maintenance and re-application might be necessary for surface treatments over the device’s lifespan to maintain their fire-retardant properties. The Welsh Building Regulations 2025 will restrict the use of combustible materials on facades, making untreated timber largely unsuitable for many solar shading applications above certain heights or in specific building types.

3.3 Composites

Composite materials offer a blend of properties not found in individual components, often combining strength, light weight, and design flexibility. However, their fire performance is highly dependent on the constituent materials, particularly the core material in panel systems.

• Metal Composite Materials (MCM): These typically consist of two thin metal sheets (e.g., aluminum, zinc, copper) bonded to a non-metallic core. MCMs are highly versatile, offering a flat, smooth finish, excellent formability, and diverse color options. However, their fire performance varies drastically based on the core material. Polyethylene (PE) cores, particularly unmodified PE, are highly combustible, melt at low temperatures, and can produce flaming droplets, contributing significantly to rapid vertical fire spread [7]. This was a primary factor in the Grenfell Tower tragedy. Consequently, the Welsh Building Regulations 2025 specifically ban the use of ‘relevant metal composite material’ (RMCM), defined as MCM with a core of greater than 30% polyethylene by mass, in external walls and specified attachments, including solar shading devices, above 18 meters [3]. Fire-rated MCMs, incorporating mineral-filled (e.g., A2 or B-s1, d0 Euroclass rating) or fire-retardant (FR) cores, are designed to significantly reduce combustibility and are often permissible under stricter regulations. Specifiers must ensure that any MCM used has certified fire ratings appropriate for the application.

• Fibre-Reinforced Polymer (FRP): These composites, such as glass fibre-reinforced polymer (GFRP) or carbon fibre-reinforced polymer (CFRP), offer exceptional strength-to-weight ratios and design flexibility. They are used for lightweight, complex-shaped shading elements. However, the resin matrix used (e.g., polyester, vinyl ester, epoxy) is typically organic and thus combustible. Fire retardants can be incorporated into the resin or applied as coatings to improve their reaction-to-fire performance, but their inherent combustibility must be carefully assessed and certified [8].

3.4 Fabrics

Fabrics are primarily used in adjustable or retractable shading devices due to their flexibility, lightweight nature, and ability to be easily deployed or stored. Their fire performance is a critical concern.

• Acrylic and Polyester: These synthetic fabrics are widely used for retractable awnings, shade sails, and external blinds due to their durability, UV resistance, and vibrant color retention. Untreated, they are combustible and can melt, drip flaming droplets, and contribute to fire spread. To meet fire safety standards, these fabrics must be treated with fire-retardant coatings or inherently manufactured with fire-resistant properties. Certified fire-retardant fabrics typically achieve classifications such as EN 13501-1 B-s1, d0 or B-s2, d0, indicating limited combustibility, very limited smoke production, and no flaming droplets. The durability of these treatments, especially when exposed to outdoor elements, is a key consideration, and manufacturers’ certifications regarding their long-term performance are crucial.

• PVC-Coated Polyester/Glass Fibre: These fabrics offer enhanced weather resistance and dimensional stability. The PVC coating can improve fire performance compared to untreated polyester, but the overall fire rating depends on the formulation. Glass fibre substrates are inherently non-combustible, and when coated, provide a superior fire rating, often achieving A2 or B classifications, making them suitable for applications with higher fire safety requirements.

3.5 Other Materials

• Glass: While not typically forming the primary shading element in the conventional sense, glass can be an integral part of advanced shading systems, such as electrochromic glass (which changes opacity) or integrated PV laminates. Glass itself is non-combustible, but its performance in fire (e.g., resistance to thermal shock, integrity) and how it is framed and sealed within a shading device must be considered. Laminated or toughened glass can offer better safety characteristics.

• Plastics (e.g., Polycarbonate, PVC): Certain plastics, particularly polycarbonate, are sometimes used for translucent canopies or small shading elements due to their light weight, impact resistance, and transparency. However, most plastics are combustible, and their use in facade applications is heavily regulated. Fire-rated grades of polycarbonate are available, but their suitability for external shading above specific heights or in critical locations must be thoroughly vetted against the regulations.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

4. Fire Safety Considerations and the Regulatory Landscape

The integration of solar shading devices into building facades necessitates a comprehensive understanding of their potential contributions to fire risk. The historical context of facade fires, combined with evolving material science and regulatory responses, has shaped a stringent framework, particularly evident in the Welsh Building Regulations 2025. This section delves into the mechanisms of fire spread, critical performance standards, and the specific regulatory mandates concerning solar shading.

4.1 The Evolution of Facade Fire Safety Regulations

The perception and regulation of fire safety in external wall systems have undergone a profound transformation, largely catalyzed by the devastating Grenfell Tower fire in London in 2017 [2]. This tragedy, primarily attributed to the rapid vertical spread of fire via combustible cladding and insulation materials, highlighted critical vulnerabilities in existing building regulations and construction practices across the UK and internationally. Prior to Grenfell, the focus was often predominantly on internal compartmentation and structural fire resistance, with less emphasis on the role of external facade materials in fire propagation. The Grenfell inquiry unequivocally demonstrated that combustible external materials could circumvent internal fire safety measures, leading to rapid external fire spread and catastrophic loss of life. This event instigated an urgent review of building regulations, leading to a tightening of restrictions on combustible materials in external wall systems for certain building types and heights [2, 9]. The Welsh Government, in alignment with this broader safety imperative, has progressively introduced and strengthened its own regulations, culminating in the Welsh Building Regulations 2025, which explicitly extend fire safety requirements to ‘specified attachments’ like solar shading devices [3].

4.2 Material Combustibility and the European Classification System (Euroclass)

The combustibility of materials is a central tenet of fire safety regulations. Materials such as untreated timber, certain plastics, and particularly Metal Composite Materials (MCMs) with highly combustible polyethylene (PE) cores, have been identified as significant contributors to rapid fire propagation on building exteriors. The Welsh Building Regulations 2025 directly address this by prohibiting the use of ‘relevant metal composite material’ (RMCM) in external walls and specified attachments, including solar shading devices, on buildings with a storey 18 meters or more above ground level. RMCM is precisely defined as MCM with a core of greater than 30% polyethylene by mass [3]. This outright ban aims to eradicate the most hazardous form of MCM from high-risk applications.

To standardize the assessment of material fire performance, the European classification system, known as Euroclass (EN 13501-1), is widely adopted [6]. This system categorizes building products based on their ‘reaction to fire’ performance, considering factors such as ignitability, flame spread, heat release, smoke production, and the generation of flaming droplets/particles. The classifications range from A1 (non-combustible, no contribution to fire) to F (easily flammable, no performance determined). Key Euroclass ratings for external facade materials typically include:

• A1: Non-combustible. Examples: stone, concrete, most metals.
• A2: Limited combustibility. Very limited contribution to fire. Examples: mineral wool insulation, fire-rated plasterboard, some fire-rated MCMs.
• B, C, D, E: Progressively increasing levels of combustibility. These classifications are further refined by ‘s’ (smoke production: s1, s2, s3) and ‘d’ (flaming droplets/particles: d0, d1, d2). For external applications, particularly for high-rise or higher-risk buildings, materials generally need to achieve A1 or A2-s1, d0 classification for significant components of the external wall and attachments.

For solar shading devices, understanding the Euroclass rating of each component — not just the primary shading element but also its supporting structure and fixings — is paramount for demonstrating compliance.

4.3 Fire Spread Mechanisms Associated with Solar Shading

Solar shading devices, by their very nature of being external projections or integrated facade elements, can inadvertently facilitate or exacerbate fire spread through several mechanisms:

• Vertical Fire Spread (Chimney Effect): Spaces behind or between shading devices and the main facade can act as vertical channels. If combustible materials are present within these channels or if a fire breaches a window, flames and hot gases can rapidly rise within this cavity, bypassing floor-to-floor fire breaks and igniting materials higher up the building [4]. This is particularly pertinent for double-skin facades or closely mounted brise soleil.

• External Surface Spread of Flame: If the surface material of the shading device itself is combustible (e.g., untreated timber, certain fabrics, non-FR composites), flames can spread across its surface. This can lead to rapid fire growth, engulfing larger sections of the facade and exposing adjacent compartments to fire.

• Flaming Droplets/Particles: Certain combustible materials (e.g., some plastics, PE-cored MCMs) can melt and produce flaming droplets or particles when exposed to heat. These can fall onto lower floors, igniting other combustible materials or entering open windows, thereby spreading fire horizontally and vertically.

• Impeding Firefighter Access and Egress: Densely arranged or projecting shading devices can hinder the deployment of ladders, aerial appliances, and external fire suppression efforts. They can also create barriers to escape routes, particularly if they are close to windows or balconies designated for emergency egress.

• Radiation and Convection: Shading devices, if ignited, can radiate significant heat to adjacent building elements, causing them to ignite or compromise their integrity. Convective heat currents carrying flames and hot gases can also transfer fire to higher levels.

4.4 The Welsh Building Regulations 2025: Specific Mandates

The Welsh Building Regulations 2025 significantly amend Part B (Fire Safety) of Schedule 1 to the Building Regulations 2010. These amendments introduce explicit requirements for ‘specified attachments,’ which now include solar shading devices, balconies, and other external features [3, 9]. Key provisions include:

• Regulation 7(2): Combustible Materials Ban: This is the cornerstone of the updated regulations. It states that ‘relevant metal composite material’ (RMCM) is prohibited on the external walls of relevant buildings (typically those with a storey at least 18 meters above ground level and containing dwellings, institutions, or other specified uses). Crucially, this prohibition extends to any part of a specified attachment, directly impacting solar shading devices. This means that if a solar shading device incorporates RMCM, it will be non-compliant for such buildings.

• Regulation 7(3): Fire Performance of Other Materials: Beyond RMCM, Regulation 7(3) mandates that other materials forming part of the external wall or specified attachment must meet specific fire classification requirements. For relevant buildings, generally, all materials forming part of the external wall construction and specified attachments must achieve at least a Euroclass A2-s1, d0 rating [3]. This is a critical requirement for structural components and core elements of solar shading devices.

• Approved Document B (Fire Safety): The supporting Approved Document B provides detailed guidance on how to comply with the Building Regulations. It outlines specific design principles, material standards, and testing methodologies. The 2025 updates will incorporate specific guidance pertaining to solar shading devices, emphasizing the need for robust fire engineering solutions where conventional compliance is challenging.

4.5 Exemptions and Their Nuances

The Welsh Building Regulations 2025 do provide certain exemptions, acknowledging that not all components of a solar shading device pose the same level of fire risk. Understanding these exemptions is crucial for design flexibility while maintaining safety:

• Exemption for Primary Shading Elements: Components whose primary function is solely to provide shade or deflect sunlight, such as awning curtains or the individual slats of a louver system (when not forming part of the structural support), are exempt from the strict A2-s1, d0 fire performance requirements [3]. This means that fabric awnings or timber slats can potentially be used, provided their structural frame and fixings meet the A2-s1, d0 standard, and the fabric/slats meet appropriate, albeit lesser, fire performance standards (e.g., B-s1, d0 or C-s2, d0, as deemed acceptable by the authority). The rationale is that these elements, while potentially combustible, are designed to be thin, lightweight, and often easily consumable in a fire, and are not intended to contribute to the structural integrity or long-term fire resistance of the overall facade. However, even for these exempted elements, designers must consider their potential to produce flaming droplets or excessive smoke, which could still contribute to fire spread or hinder escape.

• Exemption for Devices Below 4.5 Meters: Solar shading devices installed below 4.5 meters from ground level are generally exempt from the most stringent fire performance requirements [3]. This exemption recognizes the reduced risk associated with their proximity to the ground, where fire service access is typically easier and the potential for extensive vertical fire spread is diminished. However, this exemption does not negate the need for a general fire risk assessment, especially if the device is located near escape routes, entrances, or areas with high occupancy. Furthermore, this exemption often only applies to the shading device itself, and the building’s underlying external wall construction must still comply with relevant regulations, irrespective of the shading device’s height.

It is imperative that designers and specifiers do not interpret these exemptions as a carte blanche for the use of highly combustible materials. The spirit of the regulations is to mitigate risk, and any design decision, even under an exemption, should be justified by a thorough fire risk assessment and potentially consultation with building control bodies or fire engineers. The exemptions primarily allow for flexibility in the choice of the shading surface material, not for a relaxation of safety standards for the critical structural components or the overall facade integrity.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

5. Design and Material Considerations for Compliance and Best Practices

Achieving compliance with the stringent Welsh Building Regulations 2025 for solar shading devices requires a holistic and proactive approach, integrating fire safety from the earliest stages of design. This involves meticulous material selection, thoughtful construction detailing, and a comprehensive understanding of regulatory nuances.

5.1 Holistic Design for Fire Safety Integration

Effective fire safety in solar shading is not an afterthought but an intrinsic part of the design process. Architects and engineers must consider the interplay between the shading device, the building’s facade, and overall fire strategy from concept to completion. This includes:

• Early Fire Risk Assessment: Conduct a detailed fire risk assessment specific to the proposed shading system, evaluating its impact on external fire spread, occupant escape routes, and firefighter access. This assessment should consider the building’s height, occupancy, and fire strategy [10].
• Façade Interaction: Understand how the shading device interfaces with the main facade. Gaps, voids, and penetrations created by the shading system can create pathways for fire spread or hinder fire stopping. Detail interfaces to maintain the fire integrity of the external wall.
• Emergency Access and Egress: Ensure that solar shading devices do not obstruct designated escape routes, exit doors, or windows intended for emergency egress. Similarly, they should not impede access for fire service ladders or aerial rescue platforms.
• Maintenance Access: Design the devices to allow for safe and easy inspection and maintenance, especially for fire-retardant treatments or mechanical components.

5.2 Strategic Selection of Non-Combustible and Fire-Rated Materials

The most straightforward approach to compliance, particularly for higher-risk buildings (e.g., those above 18 meters), is to prioritize inherently non-combustible materials for the structural and significant components of solar shading devices.

• Metals (Aluminum and Steel): For frames, supports, and structural louvers, aluminum and steel are highly recommended due to their A1 non-combustible classification. While they can lose structural integrity at high temperatures, they do not contribute fuel to the fire. Specify appropriate finishes (e.g., anodizing, powder coating) that do not introduce combustible elements. For steel, consider its thermal performance and potential for distortion in extreme heat.
• Fire-Rated Composites: Where the aesthetic or performance benefits of composites are desired, only specify fire-rated MCMs (e.g., those with A2 or B-s1, d0 Euroclass cores) or similarly classified fibre-reinforced polymers. Crucially, obtain and verify independent third-party certification for the specific product and its intended application. The outright ban on RMCM (MCM with >30% PE core) must be strictly observed for relevant buildings [3].
• Treated Timber: For applications where timber’s aesthetic is paramount, specify timber that has been pressure-impregnated or coated with a durable fire retardant treatment to achieve at least a Euroclass B-s1, d0 or C-s2, d0 classification, as appropriate. Ensure the treatment’s longevity and require documentation demonstrating compliance and quality control [6]. Regular inspection and potential re-treatment schedules should be incorporated into the building’s maintenance plan.
• Fire-Retardant Fabrics: For awnings and external blinds, select fabrics that are inherently fire-retardant or have undergone certified fire-retardant treatments to achieve relevant standards (e.g., B-s1, d0 or C-s2, d0). The certification should specify resistance to flaming droplets and minimal smoke production. Verify the durability of the fire-retardant properties against weathering and UV exposure.

5.3 Careful Incorporation of Exempt Components with Due Diligence

The regulations provide exemptions for components whose ‘primary function is to provide shade or deflect sunlight’ and for devices below 4.5 meters from ground level [3]. While offering flexibility, these exemptions must be applied with careful consideration:

• Distinguish Structural vs. Shading Elements: Clearly differentiate between the structural framework (which must typically be A2-s1, d0 compliant for relevant buildings) and the actual shading surface (which may benefit from exemption). For example, in an awning, the metal frame needs to be compliant, while the fabric curtain might be exempt from the A2 requirement but still needs appropriate fire performance to prevent excessive spread or flaming droplets.
• Rationale for Exemption: Document the rationale for utilizing any exemption, demonstrating that the component truly falls within the exemption criteria and does not introduce undue risk. For example, a fabric awning may be exempt, but if it is excessively large, positioned directly above an emergency exit, or could produce significant flaming droplets, additional risk mitigation might be necessary.
• Below 4.5m Height: While devices below 4.5 meters are exempt from the most stringent requirements, this does not permit the use of highly combustible materials that could easily ignite and spread fire to the building or adjacent structures. A general duty of care and local authority building control requirements will still apply, potentially requiring a lower level of fire performance than for higher elements, but still avoiding highly hazardous materials.

5.4 Robust Construction Details and Installation Best Practices

Even with appropriate material selection, poor detailing and installation can compromise fire safety:

• Fire Stopping and Cavity Barriers: Ensure that any cavities or voids created by the shading system are adequately fire-stopped at compartment lines (e.g., floor levels) and around openings to prevent vertical and horizontal fire spread [4]. This is particularly critical for integrated systems or those creating enclosed channels.
• Secure Fixings: All shading devices must be securely fixed to the building structure using non-combustible fasteners. Ensure that fixings do not create thermal bridges that could compromise the integrity of fire-rated external wall elements.
• Prevention of Unintended Voids: Design to prevent the creation of unsealed voids between the shading device and the main facade that could act as a chimney or allow fire ingress into the building envelope.
• Weathering and Durability: Consider the long-term durability of fire-retardant treatments, coatings, and mechanical components. Weathering can degrade fire performance over time, necessitating robust specifications and maintenance plans.

5.5 Compliance Documentation and Stakeholder Collaboration

Comprehensive documentation is vital for demonstrating compliance throughout the project lifecycle:

• Material Specifications and Certifications: Maintain detailed records of all material specifications, including Euroclass ratings (EN 13501-1) and manufacturer certifications. This includes fire test reports for specific products and assemblies, not just generic material data [6].
• Design Drawings and Risk Assessments: Provide clear design drawings detailing the shading device’s integration with the facade, fire stopping, and material selections. The fire risk assessment should be a living document, updated throughout the design and construction phases.
• Building Control Engagement: Engage early and frequently with local authority building control officers and fire engineers. Their input is invaluable in interpreting complex regulations and gaining approval for innovative or non-standard solutions. Early engagement can prevent costly redesigns later.
• Manufacturer and Installer Accountability: Ensure that manufacturers provide clear installation instructions that align with fire safety requirements and that installers are trained and competent in adhering to these details. Quality control during construction is paramount.
• Operation and Maintenance Manuals: Provide detailed O&M manuals for the building owner, outlining required maintenance for shading devices, including checks for fire-retardant material integrity and mechanical system functionality.

5.6 Future Considerations and Life Cycle Assessment

As building materials evolve, and the demands for highly performing, sustainable facades grow, solar shading solutions will continue to innovate. This necessitates a proactive approach to fire safety:

• Design for Disassembly and Recycling: Consider the end-of-life implications for shading devices, especially those with fire-retardant treatments or composite materials, as these can impact recycling processes.
• Advanced Materials: Research and development in fire-safe advanced materials, such as bio-composites with inherent fire resistance or novel non-combustible polymers, will continue to expand the palette of options for designers.
• Smart Shading Systems: As smart building technologies become more prevalent, integrated fire detection and suppression systems within or around solar shading devices could offer enhanced safety, automatically retracting combustible elements or deploying fire suppression in the event of an alarm [11].

By diligently adhering to these design and material considerations, stakeholders can ensure that solar shading devices not only contribute to the energy efficiency and comfort of buildings but also uphold the highest standards of fire safety, aligning with the progressive objectives of the Welsh Building Regulations 2025.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

6. Conclusion

Solar shading devices are indispensable elements in modern sustainable architecture, offering substantial benefits in terms of energy efficiency, reduction in cooling loads, and enhanced occupant comfort. Their ability to dynamically manage solar heat gain positions them as critical tools in mitigating the environmental impact of buildings. However, their increasing integration into building facades, particularly in the wake of heightened global scrutiny on external fire safety, necessitates a rigorous and proactive approach to material selection and design.

The Welsh Building Regulations 2025 represent a significant legislative advancement, explicitly recognizing solar shading devices as ‘specified attachments’ and subjecting them to stringent fire performance requirements [3]. This regulatory framework, largely shaped by lessons learned from catastrophic facade fires, unequivocally prohibits the use of ‘relevant metal composite material’ and mandates high standards of non-combustibility for structural components and core elements of shading devices on relevant buildings [3, 9].

To navigate this evolving regulatory landscape successfully, designers, specifiers, and installers must adopt a holistic approach to fire safety. This encompasses prioritizing inherently non-combustible materials such as aluminum and steel for structural elements, carefully selecting fire-rated composite materials and treated timber where aesthetics or specific performance criteria dictate, and ensuring fire-retardant certification for all fabrics. Furthermore, a thorough understanding and judicious application of the specified exemptions, particularly for primary shading elements and devices below 4.5 meters, are crucial. However, even with exemptions, a fundamental commitment to fire risk assessment and appropriate material selection remains paramount to prevent any contribution to fire spread or obstruction of emergency measures.

Ultimately, the successful integration of solar shading devices demands a balance between aesthetic innovation, environmental performance, and unwavering adherence to safety standards. By diligently applying design guidelines, ensuring verifiable material compliance through rigorous documentation, and fostering collaborative engagement with regulatory bodies and fire safety experts, stakeholders can ensure that solar shading devices continue to contribute positively to building performance without ever compromising the paramount safety of occupants and the integrity of the built environment. The Welsh Building Regulations 2025 provide a clear mandate for this responsible approach, paving the way for safer, more sustainable buildings across Wales.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

References

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