Rationale

To include approved test methods for concentrations of limited DME / predominant LPG mixtures in concentrations of up to 12% DME by mass consistent with existing testing protocols utilized in LPG Gas fuel specifications today. The proposal does not reflect any requested modifications related to ASTM D1835-22 Standard specification for Liquified Petroleum Gases, as DME is not currently included in the scope of the standard. The propane shall meet the requirements of D1835 and the DME shall meet the requirements of D7901. The DME-LPG mixture shall meet the requirements set forth in D1835-22 Table 1 as transposed into D7901 proposed Table 2. The National Propane Gas Association is proposing to add this information into D7901 as DME is currently not within the scope of D1835-22. D7901 is the proposed standard for this addition based on D7901-23 Note 3—"It is expected that additional requirements for specifying dimethyl ether for fuel applications could be required as purpose-built engines and other applications develop for DME and DME – LPG blends, and such additional requirements would be balloted for inclusion into this specification, based on need and technical data." This proposed table was inspired by D1835-22 Table 1 as DME/LPG blends will be a mixture of LPG meeting the specifications of D1835-22 and DME meeting the specifications of D7901-23. It is expected that additional work will be needed to properly integrate this table and it’s D1835 referenced verbiage into D7901 so that it accurately represents the DME/LPG blend products that it is creating - and such additional requirements would be balloted for inclusion into this specification, based on need and technical data.