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Key words: lasers, calibrations, laser measurements
OST continued to provide support to the laser field compliance program through consultations on optical radiation measurements, training of FDA Electro-Optics Specialists (EOS's), and training of inspectors from Texas' Radiological Health program. The activities of OST's laser calibration laboratory provide validity to the measurements made in compliance testing programs nationwide. The OST Laser Calibration Laboratory maintains equipment for conducting high-precision optical measurements. The laboratory measurement standard is a C-series calorimeter built by NIST. To assure the validity of measurements made by OST, periodic intercomparisons are conducted with NIST, and in-house quality assurance procedures are followed. Due to the advancing age of the instruments in the EOS kits, potential replacement instruments are being evaluated. At the present time, power/energy meters and oscilloscopes are being evaluated as potential replacements.
OST continues to provide support to voluntary standards activities through participation on the ANSI Z136.4 and ISO TC172/SC9 committees. In ANSI Z136.4, a draft measurement document has been submitted to the ANSI executive committee for review. The document provides guidance for measurement procedures used in evaluating the hazards associated with lasers and optically radiating diodes. It is intended for use when the hazard classification of the product is unknown, or when it has been changed due to alteration to the product. In ISO TC172/SC9, work continues on standards for determining the laser resistance of the shafts of tracheal tubes and on a standard for surgical drapes and patient protective covers suitable for use in laser surgery.
The microwave oven survey instrument calibration program provides calibration for the instruments used by Office of Compliance and the FDA field offices. OST presently calibrates approximately 120 instruments per year for the field and for FDA inspectors. The FDA-owned survey instruments range in age from 3 to more than 20 years old. OST has been replacing one to four instruments per year, either with new instruments or with units returned from the field. OST engineers repaired 10 instruments during the last calibration cycle. OST has also been supplying calibration of standardized probes to Holaday Industries. These calibrations are performed in order to maintain a direct traceability of the leakage measuring instruments used by the oven manufacturers. [Enf, Stds, PostMS]
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Key words: latex gloves, spontaneous combustion, additives
During 1994 and 1995, four warehouse fires were reported as having been caused by the spontaneous combustion of latex examination gloves stored therein. FDA was alerted to the problem and began investigating. Latex does not ordinarily give rise to spontaneous combustion, so the suspect gloves were tested for excess generation of heat. The suspect gloves (which were powder-free latex examination gloves labeled as having been made in China) and control (powder-free latex) examination gloves were taken through identical heating profiles while the internal temperature of the glove mass was monitored. Clear overheating by the suspect gloves indicated a potential for spontaneous combustion. Infrared studies of both the surfaces (using attenuated total reflection FTIR) of the gloves as well as extracts (using transmission FTIR) from the gloves showed a difference in the chemical makeup of the suspect gloves from control gloves. It was concluded that the gloves were improperly manufactured using additives to the latex that were inappropriate and unsafe. A public health advisory was issued concerning the storage of suspect gloves. [Enf]