Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
SAE J1175-2012: Why the Bystander Noise Measurement Standard Was Cancelled
SAE J1175-2012 was a recommended practice published by SAE International that defined a pass-by noise measurement procedure for small engine powered equipment. Developed in the 1970s, it was intended to measure bystander sound levels during vehicle operation. However, the standard never gained widespread acceptance and was officially cancelled in May 2012.
Background of SAE J1175-2012
The standard was initially issued in October 1977 and reaffirmed over the years. It specified a test method where the equipment was driven past a microphone at a defined distance, simulating a bystander’s exposure. While the concept was straightforward, practical implementation faced challenges due to test site requirements and variability in results.
Why SAE J1175 Was Cancelled
The Rationale section of J1175-2012 states: “This pass-by noise procedure was developed in the 1970’s. It has never been widely accepted. With the development of stationary sound power procedures used in EU countries there is no longer a need for this document.” The shift toward stationary sound power measurements, as outlined in ISO 3744 and other standards, offered more repeatable and controlled testing conditions. These methods are now integral to EU noise regulations for outdoor equipment, such as Directive 2000/14/EC.
Current Noise Measurement Practices for Small Engines
Today, noise emissions from small engine powered equipment are typically assessed using stationary sound power methods. These tests are performed in acoustically controlled environments, allowing for precise measurement of sound power levels. The following table provides a comparison between the pass-by approach and stationary sound power testing.
| Aspect | Pass-By Noise (J1175) | Stationary Sound Power |
|---|---|---|
| Test Environment | Outdoor test track | Hemispherical measurement surface in anechoic or semi-anechoic room |
| Equipment Operation | Vehicle drives past microphone | Equipment operates at stationary condition |
| Complexity | Requires large test site, multiple passes | Controlled laboratory setup with automated measurements |
| Regulatory Acceptance | Limited | Widely accepted in EU and many other regions |
Design Insight: When designing for noise compliance, engineers must base their measurements on current, widely adopted standards. Using obsolete procedures like J1175 can result in non-compliance with regulations, especially in markets that require sound power labeling. Always verify the latest standard status.
Frequently Asked Questions
Q1: Is SAE J1175 still a valid standard?
A1: No, SAE J1175-2012 was cancelled in May 2012 and should not be used for testing or compliance.
Q2: Why was the pass-by noise procedure not widely accepted?
A2: The procedure required large test tracks and had variable results. Stationary sound power methods became the preferred approach due to better repeatability and alignment with EU regulations.
Q3: What standards have replaced J1175?
A3: Standards such as ISO 3744, ISO 3745, and SAE J192 are commonly used for sound power measurement of small engine powered equipment. Specific EU directives also specify measurement methods.
Q4: Can I use J1175 for legacy equipment testing?
A4: It is not recommended, as the standard is cancelled and may not reflect current noise emission levels under regulated conditions.
⚠️ Important: SAE J1175-2012 is cancelled. Do not rely on this standard for any design verification or regulatory compliance purposes.
🛠️ Current Practice: For noise measurement of small engine equipment, use stationary sound power methods per ISO 3744 or SAE J192. Always check the regulatory requirements of your target market.
