Under what condition is static protection not required during CNG transfer?

Static protection is essential during CNG transfer to prevent potential ignition sources caused by static electricity. The correct answer indicates that static protection is not required when both halves of the couplings are in continuous contact. This is because when the couplings are continuously connected, there is a continuous conductive path that allows any build-up of static electricity to dissipate safely, thus minimizing the risk of an electrostatic discharge that could ignite flammable gases.

In contrast, conditions such as using insulated hoses or having metallic couplings that are not in contact could allow static charge to build up without a safe path for discharge. Transferring at low temperatures might influence the behavior of gases, but it does not inherently negate the need for static protection, particularly if couplings are not continuously in contact. Therefore, maintaining continuous contact between the couplings provides a safe environment for CNG transfer without requiring additional static protection measures.