Evaluation of sizing system structure and reliability in firefighting gloves

Ill-fitting firefighter gloves negatively impact firefighters' work efficiency, performance, and safety. Although the NFPA 1971 Standard defines recommended glove sizing parameters, it remains unclear whether these sizing frameworks are accurately implemented during manufacturing. Previous studies have developed sizing systems through statistical analysis or applied population-based approaches; however, there has been a lack of research that systematically evaluates the consistency and reliability of sizing systems in actual manufactured products. This study aimed to systematically evaluate the dimensional structure and manufacturability of firefighter glove sizing systems across five commercially available manufacturers. Using 3D scanning and key dimension analysis of index finger length and hand breadth, the research assessed the degree of linearity, size interval consistency, accommodation of the target population, and alignment with NFPA standards. Findings revealed pervasive inconsistencies, including reverse intervals, irregular size progression, gaps and substantial overlaps in size distributions. These issues indicate a fundamental disconnect between intended sizing logic and the physical dimensions of manufactured gloves, leading to unreliable fit and reduced population accommodation. The study underscores that designing more size options or applying advanced statistical models alone cannot resolve fit issues if sizing systems are developed in isolation from production realities and material constraints. An integrated approach-incorporating sizing development, design specifications, and manufacturing feasibility-is essential for achieving reliable and inclusive fit outcomes. The sizing evaluation framework presented provides a quantitative, reusable method for assessing and improving glove fit in future product development.