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Dimensional Specifications for Non-Metallic Body Push-to-Connect Fittings – SAE J2494-2 (2017)
Introduction and Scope
SAE J2494-2 (2017) is a stabilized standard that specifies dimensional requirements for non-metallic body reusable push-to-connect tube fittings used in vehicular air brake systems with nylon tubing per SAE J844. The standard provides maximum envelope dimensions and general design guidance only, and it references performance requirements covered in SAE J2494-3 and FMVSS 571.106.
Dimensional, Design, and Material Requirements
The standard defines maximum envelope dimensions for fittings while leaving internal construction optional. Tolerances are ±0.4 mm (±0.016 in) for most dimensions. The minimum flow diameter must be at least 66% of the nominal tubing inside diameter. Straight threads must conform to ANSI B1.1, ISO 261, or ISO 228; taper pipe threads to SAE J476 or ISO 7-1. Fitting bodies must be made from 100% virgin thermoplastic, and threaded bases from specified brass alloys (e.g., UNS C34500). Workmanship must ensure high-quality, defect-free parts.
| Tube Size | Max L (mm) | Max L (in) | Max OD (mm) | Max OD (in) |
|---|---|---|---|---|
| 1/4 | 44.0 | 1.73 | 18.3 | 0.72 |
| 5/16 | 47.0 | 1.85 | 17.0 | 0.67 |
| 3/8 | 52.5 | 2.07 | 22.1 | 0.87 |
| 1/2 | 58.0 | 2.28 | 25.4 | 1.00 |
🛠️ Design Insight: Because the standard only defines maximum envelope dimensions, internal construction is free for manufacturer innovation as long as SAE J2494-3 performance is met.
⚠️ Important: Only 100% virgin thermoplastic is allowed for the body. Regrind is strictly prohibited.
Frequently Asked Questions
- 1. What does SAE J2494-2 cover?
- It covers dimensional specifications for non-metallic body reusable push-to-connect tube fittings for vehicular air brake systems with SAE J844 tubing.
- 2. What materials are required for the fitting body?
- The body must be 100% virgin thermoplastic, and the threaded base must be from specified brass alloys.
- 3. How are the fittings identified?
- Fittings must be marked per FMVSS 571.106.
- 4. What are the flow diameter requirements?
- The minimum flow diameter cannot be less than 66% of the nominal inside diameter of the tubing.
