Document ID: chunk:federal_register_of_legislation:F2011C00880:body:0:p6
Version: federal_register_of_legislation:F2011C00880
Segment Type: other
Provision Reference: 
Character Range: 13787–16567

the part is not greater than one tenth of that of the coil;

(b) the part of the section or part to be inspected at the time is not more than 0.5 m long;

(c) the relative permeability of the part is 500 or greater;

(d) the part has an L/D ratio of between 2 and 15.
Appendix III

This Appendix specifies procedures for the control of magnetic particle materials and equipment.

1 Overall sensitivity test

      1.1 The overall effectiveness of the equipment, materials and procedures used must be tested at intervals of not more than 7 days.

      1.2 The test must be performed by inspecting demagnetised samples containing known natural or artificial defects and assessing whether there has been any deterioration in the clarity of the indications obtained.

      1.3 If deterioration has occurred, the magnetic particle ink and equipment must be tested separately to determine where the fault lies and appropriate rectification action taken.

2 Magnetic particle inks

      2.1 Magnetic particles inks must be tested for the concentration of magnetic particles in suspension at least daily in the case of equipment in constant use, and in other cases before use.

      2.2 The tests performed must be in accordance with the following procedures:
       (Equipment required: ASTM pear-shaped 100 ml centrifuge tube, Gaetz or equivalent, with a stem calibrated in 0.1 mls.)

(a) let pump run for several minutes to agitate the suspension thoroughly;

(b) flow the bath mixture through hose and nozzle to clear the hose;

(c) fill the centrifuge tube to the 100 ml line;

(d) place the tube in its stand and leave for 30 minutes;

(e) read the volume of the magnetic particle sediment.

      2.3 The volume of the sediment should be within the range 0.1 ml–0.5 ml (preferred range 0.17 ml–4.25 ml) for fluorescent particles and 1.3 ml–2.4 ml for non‑fluorescent particles. If the volume obtained is outside these limits, the bath concentration must be adjusted accordingly and the test repeated.

      2.4 The condition of the ink should be assessed by examining the sediment for clumping, texture and colour or fluorescence. If contamination is suspected, a test for sensitivity as described in paragraph 1 of this Appendix must be performed. If an unsatisfactory result is obtained, the ink must be discarded.

3 Ultraviolet lamps

       Ultraviolet lamps together with their filters must be tested, not less than once every 3 months, for the intensity of ultraviolet light output. The intensity must be not less than 1350 lumen m­² (1020 Wcm­²) or 125 foot candle when measured with a Weston Light Meter, Model 703, type 51, or equivalent, or an Ultra-Violet Products Inc. Ultraviolet Meter, Model J-221 or equivalent, placed 380 mm from the surface of the filter.