Purpose and Scope
A properly designed, constructed, and operated perchloric acid system is likely to have minimal perchlorates present in any of the components. However, if certain components of the system were not functioning properly, or proper wash down was not happening, shock sensitive perchlorates may be present. This SOP ensures that the system has been properly inspected and tested prior to conducting maintenance or decommissioning work on surfaces exposed to perchloric acid (e.g. interior of fume hood, interior ductwork, and exhaust fan).
Policy
No de-commissioning or maintenance activities that disturb the interior duct work, interior exhaust fan, or interior of the fume hood shall be performed without following the minimum procedures to verify the system is working properly and the wash water has been tested for the presence of perchlorates.
Procedure
The perchloric acid fume hood located in room 251 Shideler Hall was specifically designed with a 5-stage wash down system. Zone 1 is located between the exhaust fan and the roof exhaust. Zones 2, 3, and 4 are located in the ductwork between the exhaust fan and the fume hood. Zone 5 is a spray bar located just above the fume hood.
Prior to conducting maintenance work the attached Daily Log --- Perchloric Acid Fume Hood Use sheet shall be reviewed. In addition, the system shall be visually inspected to verify the wash down system is operating properly. If there is any doubt regarding its effectiveness, then a supplemental method of wetting internal surfaces must be provided.
The primary reason for wetting of the system is for safety rather than for decontamination. Optional wetting methods include:
- Steaming the system for 24-hours in order to condense moisture in every possible location, or,
- Introducing a fine mist of water within the fume hood while the exhaust fan is running. The high humidity air stream will wet all surfaces in the system. Such wetting should be continued for a period of at least 12-hours, or,
- Any other wetting method that will assure prolonged water contact with all internal surfaces.
The final rinsate from the fume hood’s wash down system (or optional wetting method if applicable) shall be tested to verify the absence of perchlorates. The following information was provided by ALS Laboratories located at 4388 Glendale Milford Road, Cincinnati, Ohio 45242.
EPA method 6850 LC/MS Cost: $120/sample
Collected in 500 mL polypropylene bottles Turn around time: 8 working days
Shipped cold (no preservative) Hold time is 28-days.
Related Documents, Forms, and Tools
Attachment: Daily Log - Perchloric Acid Fume Hood Use
Revision History