This SAE Standard covers general and dimensional specifications for brass bodied reusable Push to Connect tube fittings for use in the piping of vehicular air brake systems. This type of fitting is intended for use with nylon tubing per SAE J844. See SAE J2494-3 for the Performance Requirements of Reusable (Push to Connect) Fittings Intended for Use in Automotive Air Brake Systems and U.S. Department of Transportation, National Highway Traffic Safety Administration (NHTSA) Federal Motor Vehicle Safety Standards (FMVSS) 571.
The purpose of the changes noted in this document are to harmonize the dimensioning scheme for the jam nut thickness of bulkhead unions found in Figure 1 with that of Figure 2 in this document and also Figure A5 of SAE J2494-2. In each case, the bulkhead union jam nut thickness dimensions was noted to be a “minimum”, except for that found in Table 1A and 1B for Figure 1 of SAE J2494-1 where the dimensions were noted to be a “maximum”. It is reasonable that the dimensions for the jam nut thickness, define a certain minimum thickness, as to insure an adequate thread engagement will be maintained for the integrity of the fitting. Correcting Table 1A and 1B, harmonizes the design intent for all bulkhead union, jam nut minimum thickness found in the SAE J2494-1 and SAE J2494-2 documents.