Safety Consulting Engineers, Inc. (SCE) provides impartial consulting services and guidance to the industry in process safety.

Flammability Testing of Refrigerant Blends

ASHRAE Standard 34 -2010
“Designation and Safety Classification of Refrigerants”

R number for Refrigerants.

The standard specifies rigorous testing, modeling and data collection process to which any newly formulated blend brought to the market must be subjected. The result of this process is assignment of the “R” number to the given blend.

The application seeking “R” number from SSPC 34 needs to include administrative data, properties of the blend and components, toxicity data, flammability determination, and the MSDS for both individual components and the blend.

Flammability Determination

The basis for this determination is fractionation analysis and flammability testing.

Refrigerant blend, Flammability test, “burn” result (12 Liter flask).

WCF and WCFF

For multi-component blends some components are usually flammable. Even if initially the blend is non-flammable, it may become flammable during a slow leak. Standard 34 requires that the WCF (worst case formulation) and WCFF (worst case fractionated formulation) of the given blend be determined and tested for flammability.

Flame propagation in the Burning Velocity test.

Flammability Classes and Subclasses

In a recent change to the Standard an additional subclass of flammability was added to the existing three classes: 1-nonflammable, 2- low flammable, 3- highly flammable.

The additional subclass divides the low flammable class into 2 and 2L. A measurement of burning velocity of the blend is required to have class 2L assigned. The Standard references the method used for this flammability testing.

Safety Consulting Engineers, Inc. (SCE) generally provides clients a single point source for the entire application preparation process. SCE does the flammability testing, calculations and analysis and also provides the toxicity data.

ASHRAE Standard 34 -2010
Flammability Testing of Refrigerant Blends

Safety Consulting Engineers, Inc.

Chilworth | A DEKRA Company