Document KzvkKa3w59G4BRmgdB6V99XBX

(conoco) Interoffice Communication to Steve Ashby From Tom Grumbles ate January 6, 1982 Subject PERSONAL AIR SAMPLING FOR WELDING FUMES The basic method used in sampling for welding fume is a high volume personal sampling pump and filter cassette. For total fume and iron oxide measurements the method outlined in Attachment I is used. The only addition would be to use a pre-weighed filter to allow for a gravimetric determination of total welding fume. These pre-weighed filters and the analytical services can be obtained through several contract laboratories. The majority of welding done in the shop is probably carbon steel, and a total welding fume and iron oxide determination is suitable for assessing exposures. However, if stainless steel is being welded a chromium analysis should also be done. This method is outlined in Attachment II. I would recommend using Hager Laboratories or C-TEK Laboratories to obtain pre-weighed filters and sample analysis. The address for these laboratories is below. There are other sampling considerations, such as filter placement on the welder, that we should discuss before you begin samp!ing. ajo Attachments Hager Laboratories, Inc. 4725 Paris Avenue Denver, CO 80239 (303) 371-1441 C-TEK Laboratories Continental Technical Services 9742 Skillman Dallas, Texas 75243 (214) 343-2025 CC* oooo 024.14 ATTACHMENT I Class E Substance: ircn oxiGa Standard: -? c /- t-d c i r. a Ar.alvtical Proce At eric abs: T ork. Sarrrl irritant: - i--c - - ^ -____e; i/C'ivS. Sample Size: sd. =va Ocrcb .g/n 18. 1972 g/fiicer V > - ars r trace icer :-*'2 nears a OCCGGC " a r ii er noicar a v;:n race sea gs. Shipping: Shir in a cer.tsir.er fesimei tr rrevert cacaze it. transit. 7s oooooz^5 CCR Sampling Data Sheet > S352 Substance: Chromium, Metal and Insoluble Compounds Standard: 8-hour time-weighted average: 1 mg/cu m Reference: 29 CFR 1910.93 Analytical Method: A known volume of air is drawn through a cellulose ester membrane filter to trap the chromium metal and insoluble chromium compounds present. The filter and sample are digested with hydrochloric and nitric acids to solubilize the sample and destroy the filters and any organic material. The analyte is then dissolved in a nitric acid solution, and aspirated into an atomic absorption spectrophotometer for determination of concentration. The method has been validated over the range of 0.493-1.830 mg/cu m using a 90-liter sample at 26 *C and 761 mm Hg atmospheric temperature and pressure. Sampling Equipment: A calibrated personal sampling pump whose flow can be determined to an accuracy of - 5% at 1.5 liters per minute; a 37-mm three piece cassette filter holder and a 37-mm/0.8 micrometer mixed cellulose ester membrane filter (MCEF) supported by a cellulose backup pad. Sample Size : A sample size of 90 liters is recommended. Sample at a flow rate of 1.5 liters per minute. Sampling Procedure: 1 Assemble the filter and three p ie ce fi lte r cas sette and close firmly to insure that the cente r ring sea 1 s th e edge of the filter. Examine the holder for a good f i 1 ter seal. If t he cassette will not seal tightly, i t should be d iscard ed . Secu the cassette holder together wi th tape or shri nkable ba nd . 2. Remove the cassette plugs and attach to the personal sampling pump tubing. Clip the cassette to the worker's lapel. 3. Air being sampled should not be passed through any hose or tubing before entering the filter cassette. S352-1 CCR 000002*+! 6 Data Sheer /.-`S352 4. Set the flow rate as accurately as possible using the manufacturer's directions. Record the temperature and pressure of the atmosphere being sampled. If the pressure reading is not available, record the elevation. Position the middle of the rotameter ball of the personal sampling pump to the 1.5-liter per minute calibration mark as accurately as possible. Since it is possible for the filter to become plugged by heavy particulate loading or by the presence of oil mists or other liquids in the air, the pump rotameter should be observed frequently, and readjusted as needed. If the rotameter cannot be adjusted to correct a problem, terminate the sampling. 5. After termination of sample collection, the cassettes should be firmly sealed with the plugs in both the inlet and outlet. 6. Carefully record sample identity and all relevant sample data. 7. Blank. With each batch of ten samples, submit one filter from the same lot of filters which was used for sample collection and which is subjected to exactly the same handling as the samples except that no air is drawn through it.- Label this as a blank. Specia1 Considerations: When interfering compounds are known or suspected to be present in the air, such information, including their suspected identities, should be transmitted with the sample. Shipping Instructions: The cassettes in which the samples are collected should be shipped in a suitable container, designed to prevent damage in transit. Reference: Chromium, Metal and Insoluble Compounds, h`IOSH Method No. S352. S352-2 CCR 000002417