Did You Know: NAVFAC Has Issued New Interim Technical Guidance Related to UFC 3-401-01

NAVFAC has issued new Interim Technical Guidance (ITG) that aligns with current industry practices for heating, ventilation, and air conditioning (HVAC) systems. This guidance removes restrictions on the use of Class A2L refrigerants, paving the way for safer, more efficient, and cost-effective HVAC solutions across all Navy and Marine Corps facilities.

Why the Change?

Historically, Navy and Marine Corps facility codes restricted the use of Class A2L refrigerants in occupied spaces, requiring refrigerant-containing components to be placed in unoccupied mechanical rooms or outside the building. These restrictions are considered outdated and not in sync with modern building codes and industry standards, which have widely adopted A2L refrigerants (like R-454B and R-32) as safer, more efficient alternatives to older refrigerants such as R-410A. Removing restrictions allows facilities to use widely available, UL-listed commercial products, improving maintenance support and design flexibility.

Class A2L refrigerants are classified as having lower toxicity and mild flammability. They are now standard in commercial HVAC systems, offering comparable or superior performance to traditional refrigerants. Advances in technology have made these systems safer, with integrated leak detection, enhanced ventilation, and factory-installed safety controls. A2L refrigerant systems are also more energy-efficient and offer lower life cycle costs.

The ITG is already in effect and applies to all renovations, repairs, equipment replacement, and new contruction in Navy and Marine Corps facilities. HVAC systems using A2L refrigerants must be considered in all project scopes and designs. Substitutions to A2L systems may be proposed, providing they meet or exceed performance and safety standards. In every case, HVAC systems using Class A2L refrigerants must still comply with adopted building codes and industry standards including ASHRAE. Safety systems, such as refrigerant detection and mechanical ventilation, must be commissioned and tested before system acceptance.