Fire rating testing for photovoltaic carport materials evaluates the burning behavior, flame spread, heat release, and smoke production of structural components, membrane fabrics, PV modules, and polymer parts used in solar canopy systems. This guide explains the key test items, applicable standards such as GB 8624, UL 94, EN 13501, and ISO 5660, and how manufacturers and project developers can achieve regulatory compliance through accredited third-party laboratories. Understanding these fire safety classification requirements is essential for design approval, insurance acceptance, and safe long-term operation of PV carport installations.
Technical Overview
A photovoltaic (PV) carport is a dual-function structure that combines covered parking with solar power generation. These systems integrate multiple material types within a single assembly: hot-dip galvanized or painted steel frames, aluminum alloy profiles, polymer membrane canopies, crystalline silicon PV modules, insulated cabling, junction boxes, and various elastomeric sealants. Because the structure is installed above vehicles—often directly adjacent to electric vehicle (EV) charging equipment—fire performance is a critical safety and regulatory consideration.
Fire hazards in PV carports originate from several sources, including DC arc faults in module strings, overheating connectors, cable insulation aging under sustained UV and thermal cycling, and external ignition from vehicle fires beneath the canopy. Unlike rooftop PV systems, carports have open airflow on all sides, but they also concentrate electrical equipment above an occupied space with limited egress clearance. Fire rating testing therefore serves to verify that each material layer in the assembly resists ignition, limits flame propagation, controls smoke production, and maintains structural integrity long enough for occupants to evacuate.
The fire safety evaluation of PV carport materials is governed by a framework of national and international standards. In China, GB 8624 establishes the burning behavior classification for building materials and products, while GB 50016 defines fire protection design requirements for building structures. Internationally, EN 13501 provides the European fire classification system, UL 94 addresses plastic material flammability, ASTM E84 (equivalent to UL 790) measures surface burning characteristics, and ISO 5660 quantifies heat release using the cone calorimeter method. IEC 61730 covers PV module safety qualification, including fire-related test sequences. Accredited third-party laboratories conduct these evaluations and issue test reports used for design review, fire authority acceptance, tender compliance, and export certification.
Testing Samples
Membrane and Canopy Fabric Materials
Membrane materials used in PV carport roofing and side cladding typically include PVDF-coated polyester fabric, PTFE-coated glass fiber fabric, ETFE films, and PVC-coated textiles. These polymer-based products represent the highest fire loading in the assembly and require full classification testing under GB 8624 or EN 13501. Samples must be submitted in their final production state, including all surface coatings, with dimensions and conditioning requirements specified by each test method.
Polymer and Plastic Functional Components
This category includes cable insulation and sheathing compounds, junction box housings, combiner box enclosures, cable management trays, wiring ducts, plastic fastener covers, and LED lighting housings. These components are generally evaluated using small-scale flammability methods such as UL 94 horizontal and vertical burning tests, the glow wire test per IEC 60695-2 series, and oxygen index determination per GB/T 2406.2 or ISO 4589-2.
Photovoltaic Module Laminates and Electrical Materials
PV module materials such as backsheets, encapsulant films (EVA or POE), junction boxes, connectors, and bypass diode housings form part of the electrical fire load. In addition to flammability testing of individual materials, complete modules may undergo the fire endurance and component failure tests defined in IEC 61730-2. Cable assemblies should additionally comply with flame retardancy and smoke emission requirements from the relevant IEC or GB cable product standards.
Steel and Aluminum Structural Elements
Although bare steel is non-combustible, load-bearing structural elements are tested for fire resistance rather than material flammability. Coated samples—including powder-coated beams, painted columns, and intumescent fireproof coatings applied to steel members—are evaluated to determine their fire endurance rating. Where fire-retardant coatings are specified, the coating system itself must be qualified under GB 14907 or equivalent regional standards, including adhesion, expansion behavior, and durability verification.
Sealants, Adhesives, and Coatings
Silicone sealants, structural adhesives, gaskets, and anti-corrosion coatings are tested for ignitability, self-extinguishing behavior, and combustion heat value. Although these materials represent a small mass fraction, their placement at module edges and cable penetrations means they can act as ignition propagation paths if not properly qualified.
Testing Items
Depending on the material type, product form, and target classification, a typical PV carport fire safety evaluation program includes the following test items:
- Non-combustibility test for materials seeking Class A classification, measuring furnace temperature rise, mass loss, and sustained flaming
- Gross heat of combustion determination to verify energy contribution limits for A-class products
- Ignitability under single flame source exposure, evaluating ignition time, flame spread, and flaming droplet behavior
- Single burning item (SBI) test measuring fire growth rate index (FIGRA), lateral flame spread, and total heat release
- Smoke production assessment, including smoke density grading and total smoke production indices
- Combustion droplets and debris evaluation to confirm whether flaming particles fall onto vehicles or occupants below
- Limited oxygen index (LOI) determination to quantify the minimum oxygen concentration supporting candle-like combustion
- Horizontal and vertical burning tests classifying plastics as HB, V-2, V-1, or V-0
- Glow wire ignitability and glow wire flammability index tests for live electrical components
- Cone calorimeter testing to determine peak heat release rate, total heat released, and ignition time under radiant exposure
- Surface burning characteristics testing generating flame spread index and smoke developed index
- Fire resistance testing of structural assemblies under standardized time–temperature curves to determine load-bearing endurance ratings
- Smoke toxicity assessment for enclosed or semi-enclosed canopy configurations where applicable
Testing Methods
Testing is performed according to the classification system that applies to the project jurisdiction and contract specification. The most commonly referenced frameworks are summarized below.
GB 8624 Classification Route
For projects in China, membrane and building product materials are classified under GB 8624 using a hierarchical test sequence. Class A1 requires the non-combustibility furnace test (GB/T 5464) and gross heat of combustion test (GB/T 14402). Class A2, B, and C classifications require the single burning item test (GB/T 20284) combined with ignitability testing (GB/T 8626) and, for lower grades, smoke density testing (GB/T 8627). Class D and E rely primarily on the small flame ignitability test. Most membrane materials for PV carports are specified at Grade B1 (flame-retardant) or above, and project specifications increasingly require Grade A2 or B1 for canopy fabrics above parking areas.
UL 94 and IEC 60695 Small-Scale Methods
Polymer components, electrical enclosures, and module materials are evaluated using UL 94 vertical burning tests, where afterflame time, afterglow, and ignition of cotton indicator pads by flaming droplets determine the V-0 through V-2 classifications. The IEC 60695-2-10 to 60695-2-13 glow wire series determines the glow wire ignition temperature and glow wire flammability index for parts carrying live current, which is particularly relevant for junction boxes, connectors, and combiner enclosures installed under the canopy.
EN 13501 European Classification
For export projects and installations under European building regulations, materials are tested to EN 13501-1. This system uses ISO 1182 (non-combustibility), ISO 1716 (heat of combustion), ISO 11925-2 (single flame source ignitability), and the EN 13823 SBI test to assign Euroclasses A1 through F, with additional classifications for smoke production (s1–s3) and flaming droplets (d0–d2). Canopy membranes above occupied parking typically require Class B or C with low smoke indices depending on national annexes.
ASTM E84 Surface Burning Method
For North American specifications, the Steiner tunnel test per ASTM E84 (UL 790) measures flame spread index and smoke developed index over an extended sample length. Membrane and panel products are commonly required to achieve Class A interior finish ratings, corresponding to a flame spread index of 0–25 and smoke developed index not exceeding 450 unless otherwise restricted by the authority having jurisdiction.
Cone Calorimeter and Fire Resistance Testing
ISO 5660-1 cone calorimeter testing provides performance-based data—peak heat release rate, total heat release, effective heat of combustion, and smoke production rate—useful for fire modeling and comparative material selection. Structural steel assemblies, including coated columns and beam-to-module connections, are tested to GB/T 9978 or ISO 834 time–temperature curves to establish fire endurance ratings such as R15, R30, or higher where local codes require them for canopy structures covering occupiable space.
Sample Preparation and Conditioning
All specimens must be produced using the same formulation, thickness, and manufacturing process as the commercial product. Test laboratories condition samples to constant mass at standard temperature and humidity (typically 23 ± 2 °C and 50 ± 5% relative humidity) before testing. Mounting and fixing configurations must replicate the end-use installation, since air gaps and substrate contact significantly influence flame spread results for membrane products.
Applications
Fire rating test reports for PV carport materials are used across the full project lifecycle:
- Design phase material selection and specification writing for commercial, industrial, and municipal solar carport projects
- Fire authority design review and construction acceptance inspection for canopies over public and private parking facilities
- Tender and procurement compliance verification, where bidders must demonstrate that submitted materials meet the specified fire classification
- Integrated PV-plus-EV-charging stations, where the combination of battery storage, high-power charging equipment, and canopy structures elevates fire safety scrutiny
- Factory production control and batch consistency checking during serial manufacturing of membranes, modules, and polymer components
- Export market access, where manufacturers must demonstrate compliance with destination-market classification systems such as EN 13501 or ASTM E84 through accredited third-party laboratories
- Insurance underwriting and risk assessment for asset owners and operators of distributed solar generation portfolios
- Post-incident forensic investigation and material requalification after supplier or formulation changes
FAQ
What fire rating is typically required for PV carport membrane materials?
Most project specifications require canopy membrane materials to achieve at least Grade B1 under GB 8624 or Euroclass B under EN 13501, with low smoke production classification. For carports covering high-occupancy venues, airports, or hospital parking, authorities frequently require Grade A2 or higher. The exact requirement depends on the applicable building code, canopy height, and occupant density beneath the structure.
Do steel structural components require fire rating testing?
Bare structural steel is classified as non-combustible and does not require material flammability testing. However, load-bearing members may require a fire resistance rating determined by furnace testing under GB/T 9978 or ISO 834, particularly for large-span canopies or where local codes impose endurance requirements. Any organic coating applied to steel must itself be qualified for fire performance.
Is a UL 94 V-0 rating equivalent to GB 8624 Grade B1?
No. UL 94 V-0 is a small-scale test on plastic specimens measuring self-extinguishing behavior, while GB 8624 Grade B1 is a building product classification based on larger-scale tests including the SBI apparatus. They measure different parameters and are not interchangeable. Components with electrical function are usually evaluated under UL 94 or IEC 60695, whereas construction surfaces and membranes are classified under GB 8624, EN 13501, or ASTM E84.
How many samples are required for testing?
Sample requirements depend on the test program. A full GB 8624 classification typically consumes specimens for ignitability, SBI, and smoke density testing, with several replicate pieces per method. Small-scale tests such as oxygen index or UL 94 generally require 5 to 15 specimens per material. Laboratories provide precise cutting dimensions and conditioning instructions before submission.
How long does fire rating testing take?
Standard flammability tests such as UL 94 or oxygen index can be completed within one to two weeks. A complete GB 8624 or EN 13501 classification sequence, including conditioning and multiple apparatus tests, typically requires three to six weeks. Fire resistance testing of structural assemblies may extend longer due to furnace scheduling and specimen preparation.
How often should fire testing be repeated?
Fire classification reports remain valid as long as the product formulation, thickness, and manufacturing process are unchanged. Any change of raw material supplier, coating chemistry, or product construction requires retesting or reassessment. Many procurement contracts also require periodic re-verification, typically every one to three years, to support continued compliance of serial production.