Which requirement must flexible connectors used in cylinder installations comply with?

Flexible connectors used in cylinder installations must comply with NFPA 58.6.6.1.1. This part of the National Fire Protection Association (NFPA) code specifically addresses the requirements for flexible connectors in the context of liquefied petroleum gas (LP gas) systems, ensuring safety and reliability in installations.

The rationale behind this is to ensure that the connectors can withstand the pressures and potential hazards associated with LP gas. The flexible connectors must be constructed of materials that can resist the corrosive effects of gas and the physical stresses of installation and use, which is crucial to prevent leaks and maintain the integrity of the gas supply system.

Additionally, adhering to NFPA standards helps standardize safety measures across the industry, promoting consistent practices that protect both the installers and the end-users from hazardous situations. Compliance with NFPA 58 is essential for maintaining a safe working environment and adhering to legal and regulatory standards in LP gas operations. This makes the chosen answer essential for anyone working with LP gas installations, ensuring both safety and operational efficacy.