FLAMEBAR A2L REFRIGERANT ENCLOSURE SYSTEM
IMPROVED CONSTRUCTABILITY, LESS SPACE, LESS COST
A2L refrigerant piping is mandated by code to be protected and contained in 2-hour enclosures. Learn more about the solution for A2L refrigerant piping.
Flamebar fire-rated enclosures contain and protect flammable A2L refrigerants. The system offers a number of benefits:
- Floor Space Advantage: Compact—occupies less depth and width for any configuration of two or more pipes.
- Simplicity: Avoids difficult to construct drywall assemblies and allows for horizontal offsets.
- Serviceability: Simplifies maintenance access with easily opened ‘clamshell’ enclosures, and built-in access doors as required.
- Convenient: Supplied with all materials required to complete the job.
- Vapor Barrier Savings: Does not require an additional vapor barrier. Insulation options available.
- Ventilation: Accommodates mechanically or naturally ventilated designs.
A2L SYSTEMS MUST PROTECT AND CONTAIN
The 2021 International Mechanical Code and ASHRAE 15 2022 Standard require that A2L refrigerant piping systems penetrating two or more floors be protected with a fire-rated enclosure that is sealed to contain refrigerants in the event of leaks. For buildings with four stories or more, two-hour rated and vented assemblies are required.
Manufacturer transition to A2L equipment, timing of jurisdictional adoption codes, and date of permitting will drive rate of implementation. Ensure compliance by choosing the Flamebar fire-rated A2L refrigerant enclosure.
WATCH THE FLAMEBAR A2L REFRIGERANT ENCLOSURE SYSTEM BEING INSTALLED
The pre-fabricated ductwork design of the Flamebar fire-rated A2L refrigerant enclosure system helps contractors save both time and materials during installation. See for yourself just how easy it is to install with this step-by-step video demonstration. Along with installation instructions, the video also provides a detailed overview of all the components included in the A2L refrigerant enclosure system. Watch and learn techniques to complete an installation quickly, safely, and securely!
Who We Work With
Flamebar fire-rated HVAC systems benefit different team members throughout the construction process. Learn more below.
Engineers
Leading engineering firms in the US and worldwide simplify their designs by using Flamebar as their holistic fire-rated solution.
Mechanical / Sheet Metal
Flamebar simplifies the installation process, saving valuable project time.
General Contractors
Conquest delivers just-in-time (JIT) multi-hour fire resistive assemblies and ductwork directly to project sites
Owners / Developers
Flamebar replaces multiple disjointed materials with one holistic solution, resulting in a lower total install cost.
FREQUENTLY ASKED QUESTIONS
The AIM Act directed the EPA to phase down HFCs, which accelerated the HVAC industry’s transition to lower-GWP alternatives. Most mini-split, multi-split, and VRF equipment manufactured today uses A2L refrigerants such as R-32 and R-454B. Because these refrigerants are classified as mildly flammable under ASHRAE Standard 34, building codes now impose ventilated shaft and enclosure requirements for refrigerant piping routed through buildings that did not apply to previous refrigerant generations.
A2L refrigerants are a classification under ASHRAE Standard 34 for refrigerants that are mildly flammable. When A2L refrigerant piping is routed through interstitial spaces, wall cavities, or above-ceiling spaces without ventilated enclosures, a leak has no dispersion pathway and refrigerant can accumulate to concentrations within the flammable range. The ventilated and fire-rated enclosure and shaft requirements exist to prevent this scenario. Current mini-split, multi-split, and VRF equipment lines broadly use A2L refrigerants.
The 2021 and 2024 International Mechanical Code (IMC) require ventilated and fire-rated shafts for all A2L refrigerant piping in human comfort applications. ASHRAE Standard 15:2022 with amendments permits exemptions based on Refrigerant Concentration Limit (RCL) calculations for smaller systems, but this does not override IMC requirements in IMC jurisdictions. Jurisdiction adoption of specific code editions varies; confirm with your local AHJ.
The Flamebar A2L Enclosure is a ventilated, fire-rated enclosure and shaft system designed specifically for A2L refrigerant piping. It provides both the fire resistance and the ventilation pathway required by current model codes.
The Flamebar A2L Enclosure is a purpose-built, listed fire-rated enclosure and shaft system for A2L refrigerant piping. It provides the ventilation pathway and fire resistance required. Unlike field-built drywall shaft alternatives, it is factory-manufactured and arrives as a complete listed system.
The AIM Act’s HFC phase-down has accelerated the transition to A2L refrigerants across the HVAC industry. IMC 2021/2024 responds to this by requiring ventilated and fire-rated shafts for A2L piping in buildings. Specifying the shaft system at the design stage ensures the project meets current code requirements in jurisdictions that have adopted IMC 2021 or 2024.
Several factors create specification complexity: varying code adoption across jurisdictions, the interaction between ASHRAE Standard 15 RCL exemptions and IMC mandatory requirements, the need to coordinate enclosure routing with the mechanical system design early, and selecting a product with appropriate fire-resistance ratings and ventilation performance. Conquest can provide code path guidance, specification language, and design support.
The 2021 and 2024 International Mechanical Code require ventilated and fire-rated shafts and enclosures for A2L refrigerant piping in human comfort applications routed through buildings. This applies regardless of building height. In multi-story buildings, this means all A2L refrigerant line sets routed through floor assemblies, wall cavities, and interstitial spaces must be enclosed in a listed ventilated and fire-rated system. Jurisdiction adoption of specific IMC editions varies; confirm with your local AHJ.
The Flamebar A2L Enclosure is a factory-built, listed enclosure for A2L refrigerant piping that can be built into a shaft assembly and provides ventilation and fire resistance in a compact shape factor. For vertical riser applications, the Flamebar Compact Shaft reduces conventional multi-layer shaft wall construction from 6 or more inches to approximately 2-1/4 inches. Engage Conquest Flamebar early in design so enclosure routing and sizing are reflected in shaft layouts before construction documents are issued.
The Flamebar A2L Enclosure is a factory-built, listed system that provides the ventilation pathway and shaft fire resistance required by IMC 2021/2024 for A2L refrigerant piping.
Flamebar A2L Enclosures are suitable for all unitary (VRF and split) HVAC systems in any building type where A2L refrigerant piping is routed through occupied or interstitial/wall/ceiling spaces, including office buildings and data centers. The applicable code requirements are governed by the IMC edition adopted in the project jurisdiction, not by building type.
The Flamebar A2L Enclosure is a purpose-built, listed fire-rated and ventilated enclosure and shaft system for A2L refrigerant piping. It integrates with the broader Flamebar fire-rated duct product family.