| Primary purpose | Guide for evaluating and specifying wood–plastic composite products and materials. | Test method for determining flexural properties of plastic lumber and related products. | European product and material requirements for wood–plastic composites; Part 1 covers general characteristics and Part 4 covers decking profiles. | The exact standard edition, product type, test laboratory, specimen preparation procedure, and complete test report. |
| Flexural performance | Identifies flexural strength and stiffness as important performance characteristics for structural or load-bearing applications. | Uses bending tests to determine flexural modulus of elasticity and flexural strength or modulus of rupture. | Requires relevant mechanical performance to be assessed according to the applicable product category and test procedures. | Flexural modulus in MPa, flexural strength or MOR in MPa, load–deflection curves, span, cross-section, loading rate, and failure mode. |
| Test configuration | Recommends selecting test methods that reflect the intended end use, including outdoor exposure and decking-related performance. | Typically uses a three-point bending arrangement with a defined support span, specimen geometry, and loading rate. | The applicable part and product specification determine the required test arrangement and evaluation criteria. | Test span-to-depth ratio, specimen dimensions, support and loading nose details, loading direction, and number of specimens. |
| Water absorption and thickness change | Treats moisture-related dimensional stability and water absorption as key characteristics for exterior WPC products. | Primarily addresses flexural testing; water absorption and dimensional change normally require separate applicable methods. | Includes moisture-related characteristics and dimensional changes relevant to WPC products and decking profiles. | Water absorption percentage, thickness swelling percentage, test duration, immersion conditions, and measurement locations. |
| Dimensional stability | Considers changes caused by moisture and temperature because they can affect installation, gaps, and service performance. | Dimensional stability is not the principal property measured by this flexural test method. | Addresses dimensional variation and product tolerances for the applicable WPC product category. | Length, width, and thickness changes after conditioning; coefficient of thermal expansion where relevant; profile tolerances in millimetres. |
| Weathering and colour stability | Provides a framework for considering weatherability, colour change, surface appearance, and durability during product evaluation. | Does not determine outdoor weathering or colour retention. | Relevant appearance and durability characteristics are evaluated using the applicable European procedures and product requirements. | Accelerated-weathering method, exposure time, irradiance or UV conditions, colour-change measurement, surface defects, and post-exposure strength results. |
| Slip resistance | Identifies surface safety and slip resistance as important considerations for decking applications. | Not measured by the flexural test method. | Decking profiles are evaluated for applicable surface characteristics, including slip-related performance where required. | Slip-resistance test method, dry and wet results, test direction, surface condition, and any stated classification or limit. |
| Fastener and installation compatibility | Encourages evaluation of product characteristics that affect installation, fastening, serviceability, and end-use performance. | Does not by itself qualify screws, clips, joist spacing, or installation systems. | Product installation and profile requirements must be considered together with the applicable decking specification and instructions. | Approved fastener type, pull-out or holding data where relevant, recommended joist spacing, edge distances, expansion gaps, and installation drawings. |
| Fire performance | Fire behaviour may need separate evaluation when required by the building application or local code. | Not a fire-classification test method. | Fire-related classification and testing are handled under the applicable European fire standards and regulatory requirements. | Reaction-to-fire test standard, classification, specimen construction, substrate, mounting method, and report scope. |
| Quality-control indicators | Supports a systematic specification and testing program rather than relying on a single property. | Provides repeatable flexural data when specimen preparation, conditioning, and machine settings are controlled. | Supports conformity assessment using defined product characteristics, test methods, and documented production control. | Mean, minimum, maximum, and coefficient of variation; batch identification; conditioning records; calibration certificates; and traceable sample records. |
| How to interpret compliance | A guide does not automatically create a universal pass/fail value for every WPC decking product. | A test result is meaningful only when the specimen, conditioning, loading method, and acceptance criteria are clearly defined. | Compliance depends on the applicable part, product category, declared use, and stated European requirements. | Do not compare isolated numbers; compare complete, third-party test reports against the requirements for the intended climate and installation. |