Spray Device Indexing
Early in the development of highly automated pharmaceutical and biotech production facilities, validation personnel and regulatory authorities require some method of confirming that all vessel surfaces would be covered with flush, wash and rinse solutions during the CIP program. The industry developed and applied a test using riboflavin as an indicator medium. Riboflavin is water soluble, fluoresces under UV light, is easily applied by spraying, and easily removed by rinse water alone. As users became more skilled in the use of this technology it was recognized that the criteria that made removeable sprays desirable; i.e., for inspection and or removal of insoluble debris during the commissioning and validation process, resulted in frequent failure to properly position the spray following re-installation.
Assurance of Proper Spray Orientation Spray Nozzle with Index Tab
Common methods of assuring proper spray orientation included (1) adding a notch on the perimeter of the TC cap used to clamp the spray into the installation nozzle and (2) weld an elbow on the supply tube to position the spray properly when it was clamped to the end of a properly positioned and rigidly supported CIP supply line. Validation personnel often found that the overall pattern in a spray was correct, but that its position on the nozzle needed to be “tweaked” to provide proper coverage. And, everybody wanted to know that the spray was always in the correct position. A notch in the TC cap was not visible following installation of the clamp and the use of a welded on elbow prevented the spray from being rotated even a few degrees. ESC Indexed Spray in Nozzle.
A method of assuring proper indexing, hence coverage in accordance with design requirements, is to weld a “L” shaped rod to the spray tube extension beyond the installation flange that will intersect a tab welded to the nozzle in the tank head. The photos at the right illustrate this method of indexing fixed static spray devices. Unless otherwise specified, ESC follows the guidelines established by ASME BP-2012 SD.188.8.131.52 Static Spray Device Requirements item (a) which states “Static spray devices shall have a positioning device (preferred) or mark to allow for proper orientation during re-installation, as static devices are orientation sensitive.