进行了测试，以测量由绕线柔性风管和刚性金属板风管组成的轻型商用风管系统中的压力损失。试验确定了多分支系统中使用的不同长度柔性管道的压力损失。ASHRAE手册指南建议商业应用的软管长度不得超过6英尺（1.83米）。与满足该建议的管道系统相比，使用11英尺（3.35米）柔性管道支管连接至扩散器的系统的总压力损失损失为3%。 使用完整长度的适当尺寸柔性管道的系统产生的总压力损失比符合现行要求的多支管系统低22%。关于支管中测得的流量不平衡，使用软管支管长度大于现有限制6英尺（1.83米）的系统显示出可忽略的不利影响。引用:佛罗里达州奥兰多2020年冬季会议技术论文

Tests were performed to measure pressure losses in lightcommercialduct systems comprised of wire-wound flexibleduct and rigid sheet metal duct. The tests determined the pressureloss associated with various lengths of flexible duct usedin multi-branch systems. ASHRAE Handbook guidelinesrecommend a maximum 6 ft (1.83 m) length of flexible duct forcommercial applications. The total pressure loss penalty for asystem that utilized 11 ft (3.35 m) of flexible duct branchesconnected to diffusers was 3%, compared to a duct systemmeeting this recommendation. A system using completelengths of properly sized flexible duct yielded a total pressureloss that was 22% less than a multi-branch system whichconformed to prevailing requirements. Regarding themeasured flow imbalance in the branches, systems that usedflexible duct branch lengths greater than the existing limit of6 ft (1.83 m) exhibited negligible adverse effects.