scope:

This standard specifies all the information necessary to determine, declare, and verify airborne emission sound pressure level characteristics of MR EQUIPMENT under standardized conditions in the MR EXAMINATION ROOM. It specifies minimum requirements for measurement methods and operating conditions that shall be used for the test. This standard measures the maximum exposure the PATIENT may experience and the representative average MR EQUIPMENT output at the position for an MR WORKER standing beside the PATIENT table.

The use of this standard ensures the reproducibility of the measured airborne noise-emission characteristics within specified limits determined by the grade of accuracy of the basic airborne noise measurement methods used. Noise measurement methods according to this standard are engineering methods (grade 2). All measurements as defined in this standard are acceptable for ISO 4871 declarations. Translation to sound power levels is not required for the purpose of this standard.

This standard is a type C standard as stated in ISO 12001, also known as a noise test code. MR EQUIPMENT is considered PERMANENTLY INSTALLED EQUIPMENT, and this standard provides type test methodologies for the scanner as installed. All PERMANENTLY INSTALLED MR EQUIPMENT is considered to be large for the purposes of ISO Acoustic Noise standards. This in situ determination of the airborne emission sound pressure level at a specified PATIENT and MR WORKER position is necessary for:

• Demonstrating compliance with requirements in IEC 60601-2-33

• A harmonized and consistent method to measure acoustic emissions

• Declaring a noise emission value, such as required by the EU Machinery Directive 2006/42/EC

This standard may also be useful for design and verification of noise control provisions.

When provisions of this type C standard for acoustics are different from those that are stated in A or B standards, the provisions of this type C standard take precedence.

The standard is applicable to all types of PERMANENTLY INSTALLED MR EQUIPMENT, such as "horizontal, cylindrical bore" and "perpendicular to PATIENT's long axis," with or without an acoustically isolated examination room, and with or without separate MR operator room. NON-PERMANENTLY INSTALLED MR EQUIPMENT may be able to adapt these methods for their particular operations, taking into consideration the variability of the room acoustics. The sound pressure level is determined for a specified PATIENT and MR WORKER position, inside the examination room in which the scanner is installed and which is considered part of the MR SYSTEM. Noise measurements are performed inside the examination room in accordance with ISO 11201, and sound pressure levels can be used without environmental corrections. This standard characterizes clinically configured systems and does not consider the implications of IRB-controlled operation modes. However, the test methods may be applied to characterize system performance for use under IRB.

Measurement methods described in this standard have not been developed to assess emissions relevant to servicing actions to the equipment, but may be adapted for such purposes.

The RESPONSIBLE ORGANIZATION may find the noise emissions determined by this standard useful for designing noise control for the building but is otherwise outside the scope of this standard.

This procedure has been designed for measuring peak sound pressure levels (SPL) up to 140 dB(C). Above 140 dB(C), the use of more sophisticated equipment and methods may be required. Note that this edition of the standard has converted from unweighted peak SPL measurements to C-weighted measurements to align with the changes in IEC 60601-1 ed 3.1 (2015). The measurement methodology provided in this standard can also be used to measure unweighted peak acoustic noise exposures.