AHRTI to begin A3 flammability tests

The Air Conditioning, Heating and Refrigeration Technology Institute (AHRTI) plans to begin work this week on a study of the risks posed by A3 (flammable) refrigerants.

The study, which covers phase two of AHRTI Project 9007, is called “Benchmarking Risk by Whole Room Scale Leaks and Ignitions Testing for A3 Refrigerant.” It follows phase one of Project 9007, completed last year, which did the same testing on A2L refrigerants.

Project 9007 is part of a broader research program on flammable refrigerants launched last year and supported by AHRI, which has invested $1 million, ASHRAE ($1.3 million), the California Air Resources Board ($300,000) and the U.S. Department of Energy ($3 million). AHRTI is the research arm of AHRI, Arlington, Va.

“The test set up has been completed and ready for testing as of now,” said Xudong Wang, director, research for AHRI. “We will start off with two tests this week and next week and then review and see if any adjustment is needed.”

The initial part of the A3 project involves testing under a controlled environment, using a model room 3.6 m by 2.4 m by 2.4 m, according to Wang. Various leak rates, heights, oil concentrations and room conditions will be used.

The second part does testing under a “whole room” scale. It encompasses residential split air conditioners in a hallway application; commercial air conditioning, including a rooftop unit and a packaged terminal air conditioner (PTAC); and self-contained reach-in and walk-in coolers.

The A3 tests will be “as equivalent as possible” to the A2L tests in terms of mass flow rate, percentage of LFL (lower flammability limit,” Wang said last September at the Danfoss EnVisioneering Symposium in Orlando, Fla.

At the AHR Expo in Chicago last month, Wang said the A3 testing would be completed in six months.

Meanwhile, ASHRAE is engaged in three A3-related projects.

ASHRAE-1806, “Flammable Refrigerants Post-Ignition Risk Assessment,” will be completed in late 2018, said William Goetzler, managing director, energy practice at Navigant, who spoke at AHR Expo. This project, which covers both A2L and A3 refrigerants, will consider a risk assessment of the creation of hydrofluoric acid in the combustion of A2L refrigerants, he said.

Gexcon is the prime contractor for the 1806 project; Navigant is the subcontractor responsible for the risk assessment.

Results from ASHRAE-1807, “Guidelines for Flammable Refrigerant Handling, Transporting, Storing and Equipment Servicing and Installation,” are due to be released soon, said Goetzler. The project covers both A3 and A2L refrigerants.

ASHRAE-1808, “Servicing and Installing Equipment Using Flammable Refrigerants: Assessment of Field-Made Mechanical Joints,” is being handled by Creative Thermal Solutions (CTS), Urbana, Ill. “The project will be completed very soon on our end,” said Predrag (Pega) Hrnjak, president of CTS.