CGA V-21为压缩气体的填充者和用户提供扭矩指南，用于密封各种CGA钢瓶阀门出口连接件，CGA V-17《CGA 630/710系列超高完整性服务连接件的搬运和使用指南》、医用阀轭连接件、医用DISS连接件、潜水器连接件、，和余压阀（RPV）连接。通过遵循这些指南，用户可以减少泄漏和对连接的损坏。

CGA V-21 provides fillers and users of compressed gases with torque guidelines for sealing various CGA cylinder valve outlet connections except for the 630/710 connections covered in CGA V-17, Guideline for Handling and Use of CGA 630/710 Series Ultra High Integrity Service Connections, medical yoke connections, medical DISS connections, scuba connections, and residual pressure valve (RPV) connections. By following these guidelines, users can expect to reduce leaks and damage to the connections.