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Significance and Use
5.1 Paper machine rolls can range in size from 2.4 to 9 m [8 to 30 ft] long, with a shell thickness of from 12.5 to 75 mm [0.5 to 3 in.,] and 300 to 1200 mm [12 to 48 in.] diameter. Depending on purpose, paper machine rolls can weigh as little as 60 000 kg [13 000 lb] to as much as 27 500 kg [60 000 lb].
5.4 Traditional AE examination, whereby the roll is subjected to load greater than service load to detect crack extension, risks damage to the roll and is best employed as a follow-up NDT examination.
5.6 Excess background noise (overhead cranes, nearby maintenance activities) may distort AE data or render it useless. Users must be aware of the following common sources of background noise: bearing noise (lack of lubrication, spalling, and so forth), mechanical contact with the roll by other objects, electromagnetic interference (EMI) and radio frequency interference (RFI) from nearby broadcasting facilities and from other sources. This practice should not be used if background noise cannot be eliminated or controlled.
5.7 Other Non-destructive test methods may be used to evaluate the significance of AE indications. Traditional AE has been used to confirm the existence of the AE indication and fine tune the location. Magnetic particle, ultrasonic and radiographic examinations have been used to establish the position, depth and dimensions of the indication. Procedures for using other NDT methods are beyond the scope of this practice.
1.4 The AE measurements are used to detect or locate emission sources, or both. Other nondestructive test (NDT) methods must be used to evaluate the significance of AE sources. Procedures for other NDT techniques are beyond the scope of this practice. See Note 1.
1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standards.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
E543 Specification for Agencies Performing Nondestructive Testing
E650 Guide for Mounting Piezoelectric Acoustic Emission Sensors
E976 Guide for Determining the Reproducibility of Acoustic Emission Sensor Response
E1316 Terminology for Nondestructive Examinations
E2075 Practice for Verifying the Consistency of AE-Sensor Response Using an Acrylic Rod
E2374 Guide for Acoustic Emission System Performance Verification
E2598 Practice for Acoustic Emission Examination of Cast Iron Yankee and Steam Heated Paper Dryers
ASNT StandardsANSI/ASNTCP-189 Standard for Qualification and Certification of Nondestructive Testing Personnel
AIA DocumentNAS-410 Certification and Qualification of Nondestructive Testing Personnel
ICS Number Code 17.140.20 (Noise emitted by machines and equipment); 85.100 (Equipment for the paper industry)
UNSPSC Code 23151900(Paper making and paper processing machinery and equipment and supplies)