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For problems with accessibility in using figures, illustrations and PDFs in this method, please contact the SLTC at (801) 233-4900.
These procedures were designed and tested for internal use by OSHA personnel. Mention of any company name or commercial product does not constitute endorsement by OSHA.
||Air, Wipe (Smear Tabs for particulate fluoride)
|OSHA Permissible Exposure Limits
Final Rule Limits
Fluorides (as F):
2.5 mg/m3 Time Weighted Average (TWA)
3 ppm TWA
6 ppm Short-Term Exposure Limit (STEL)
| Transitional Limits
Fluoride Dust (as F):
2.5 mg/m3 TWA
3 ppm TWA
A known volume of air is drawn through a cassette containing a mixed-cellulose ester (MCE) filter and backup pad using a calibrated personal sampling pump.
A known volume of air is drawn through a three-piece cassette containing a MCE filter and a sodium-carbonate treated backup pad using a personal sampling pump.
|Recommended Air Volumes:
|Recommended Sampling Rate:
||Filters (MCE) are fused with sodium hydroxide, and treated back-up pads are desorbed with deionized water. Analysis is performed using an ion specific electrode and the method of standard additions. All samples are analyzed for total fluoride content.
25 µg (25-mL sample solution volume)
|Precision and Accuracy
Overall Analytical Error
350 to 700 µg load (as HF)
||Validated Analytical Method
|Date (Date Revised):
||December 1988 (Feb. 1991)
Commercial manufacturers and products mentioned in this method are for
descriptive use only and do not constitute endorsements by USDOL-OSHA.
Similar products from other sources can be substituted.
Division of Physical Measurements and Inorganic Analyses
OSHA Technical Center
This method describes the collection and analysis of
airborne hydrogen fluoride or particulate fluoride-containing
compounds in the workplace. It is applicable for both Short-Term
(STEL) and Time Weighted Average (TWA) exposure evaluations.
2. Range and Detection Limit
In the past, samples for determination of particulate and gaseous fluoride
compounds were collected using the sampling procedure mentioned in this
method with one exception. For HF sampling, the MCE filter was previously
placed on the chemically-treated backup pad. The filter and
treated pad are now separated within a three-piece cassette.
Samples have always been analyzed at the OSHA laboratory using an ion
specific electrode (ISE)/standard addition technique.
An air sample is taken by drawing a known amount of air through a cassette
containing a mixed-cellulose ester (MCE) membrane filter for
the collection of particulate fluoride compounds. For the collection of
hydrogen fluoride (HF) gas, a sodium carbonate-treated
back-up pad is placed behind the MCE filter.
The MCE filter containing particulate fluoride is fused with sodium
hydroxide to facilitate solubility of the particulate. The resulting
alkali flux is dried, neutralized with hydrochloric acid, and then diluted
to a specified volume with deionized water. The sodium
carbonate-treated back-up pad is desorbed with
deionized water. The pH of each sample solution is adjusted to be within a
pH of 5 to 10. Immediately before analysis, each sample is combined
with Tris-Tartrate (T-T) complexing buffer
solution. The concentration of each sample is determined by a standard
addition technique using an ISE for fluoride.
1.3. Advantages and Disadvantages
1.3.1. This method is a simple sampling and analytical procedure able
to detect fluoride over a large concentration range.
1.4. Physical and Chemical Properties (8.1.)
1.3.2. Analytical interferences are minimized by the addition of a
buffer and use of the standard additions technique. Ions commonly
associated with fluoride in work atmospheres (i.e. chloride, bromide,
iodide, sulfate, nitrate, phosphate, and acetate) do not interfere with
1.3.3. The instrumentation and sample preparation are inexpensive.
1.3.4. A disadvantage of this method is the sample preparation which
involves a tedious sample flux technique.
1.3.5. Another disadvantage is the tendency for ISE readings to drift
when measuring low concentrations.
Some properties and additional information regarding hydrogen fluoride are
listed below. Particulate fluoride compounds are too numerous to describe;
sodium fluoride (NaF) is included below as an example of a soluble
||Hydrofluoric acid, hydrogen fluoride
||Variety of compounds, fluoride ion, perfluoride
||Colorless, fuming mobile liquid. Attacks glass and
any silicon-containing material.
||Clear crystals or white powder
||(HF 38% solution)
||0.988 (liquid @ 14 °C)
||2.558 (14 °C)
||Soluble in water
||Soluble in water
||Strong irritant to eyes, skin, and mucous
membranes. Toxic by inhalation or ingestion.
||Tissue irritant, toxic by inhalation or ingestion.
||Aluminum production, fluorocarbons, stainless
steel pickling, glass etching, oil well acidizing, gasoline
production, uranium processing, automotive chromium brightening.
||Water fluoridation (~ 1 ppm), degassing steel,
fungicide and rodenticide, wood preservative, electroplating,
toothpaste additive, glass manufacture, disinfectant (in
fermentation), dental prophylaxis.
The analytical range is from 25 to 2,000 µg fluoride.
Samples larger than 2,000 µg can be diluted and analyzed. An estimated
detection limit of 25 µg is used. This detection limit is based on the
lowest concentration standard used in the analysis.
3. Method Performance
Quality control data (8.2.) from the OSHA Technical Center (OSHA-SLTC)
indicate an average recovery of 99% with a coefficient of variation of 0.057
for 60 samples spiked with sodium fluoride. The overall analytical error for
these quality control samples (analyzed from 1986 to 1990) was ±12.4%.
Factors which may influence precision and accuracy include electrode
temperature, drift, and noise.
The sampling portion of the method had previously been evaluated at a flow
rate of 1.5 L/min (see reference 8.3. for more information).
4. Interferences (Analytical) (8.4.)
Interference due to OH¯ ion can be controlled by maintaining the pH between
5 and 10. Loss of fluoride from complex formation of fluoride ion with
polyvalent cations is controlled by the addition of a buffer during
analysis. Interferences can further be minimized using a standard additions
technique. Formation of HF and HF¯ at low pH is avoided by using a sample
matrix having a pH > 5. Interferences from complexing agents
such as hydrogen ion (H+), aluminum, silicon, or iron [Fe(3+)]
are minimized by using a buffer and a standard additions technique.
5.1. Equipment - Air Samples (Note: Any
chemicals used in sampling media preparation should be reagent grade or
collection: Mixed cellulose ester (MCE) filters (0.8 µm pore
size), cellulose backup pads for filter support, and two- or
three-piece cassettes, 37-mm diameter, (part no.
MAWP 037 A0, Millipore Corp., Bedford, MA).
5.2. Equipment - Wipe Samples
5.1.2. Particulate and hydrogen fluoride collection:
In addition to the MCE filter, a filter spacer (Cat. No. 225-23,
SKC Inc., Eighty Four, PA) and a chemically-treated backup
pad is also used. The spacer is a support ring for the MCE filter. The
treated pad ensures capture of HF. The backup pads are treated using the
Using a forceps, remove the MCE filters from
the three-piece cassettes and use the opened cassettes as supports for
backup pad impregnation. Each backup pad should be resting on the ridge
of the middle insert of the cassette and not in contact with the
cassette base when impregnating.
- Pipets, 0.5 mL
- Sodium carbonate (Na2CO3)
- Glycerol (C3H8O3)
- Impregnation solution [Na2CO3 solution with
glycerol] - prepare by dissolving 4.0 g Na2CO3 in 50 mL
deionized water, add 2 mL glycerol, and dilute this solution to 100 mL
with deionized water.
Slowly pipet 0.5 mL of the impregnation solution over the entire backup
pad and let dry overnight. Assemble the cassettes such that the backup
pad resides in the lower section (the cassette outlet), and the MCE
filter and filter spacer is in the upper section (the inlet) as shown:
Use the treated backup pads within 2 months of
5.1.3. Gel bands (Omega Specialty Instrument Co., Chelmsford, MA) for
sealing cassettes. Seal cassettes with the bands after assembly.
5.1.4. Sampling pumps capable of sampling at 1.5 liters/min (L/min) with
less than ±5% pump error.
5.1.5. Assorted flexible tubing.
5.1.6. Stopwatch and bubble tube or meter for pump calibration.
5.2.1. Smear tabs (part no. 225-24, SKC Inc.,
Eighty Four, PA).
5.3. Sampling Procedure - Air Samples (Also see note in Section 7.3.)
5.2.2. Deionized water.
5.2.3. Scintillation vials, 20-mL (part no. 74515 or 58515, Kimble, Div.
of Owens-Illinois Inc., Toledo, OH) with polypropylene or
Teflon cap liners.
5.3.1. Connect sampling media for calibration
purposes to each pump and calibrate to approximately 1.5 L/min.
5.4. Sampling Procedure - Wipe Samples
5.3.2. Remove the calibration media and connect the appropriate sampling
media to each pump. For particulate fluoride sampling only, use the
media described in Section 5.1.1. For HF and particulate fluoride, use
the media listed in Section 5.1.2. Make sure the filter cassette is
connected to the pump with flexible tubing such that sampled air enters
the MCE filter first.
5.3.3. Place the sampling assembly on the employee or workplace area so
it does not interfere with the work being performed.
5.3.4. Collect air samples at a flow rate of 1.5 L/min. Whenever
possible for TWA measurements, take consecutive samples for 1 h each.
Take enough samples to cover the entire workshift. Observe each cassette
during sampling to make sure the filter does not become overloaded.
5.3.5. Take samples for at least 15 minutes for STEL measurements. The
minimum suggested total air volume for STEL determinations is 22.5 L.
5.3.6. Replace the end plugs into the filter cassettes immediately after
5.3.7. Securely wrap each sample cassette end-to-end with an OSHA Form
21 sample seal.
5.4.1. Wear clean, impervious, disposable
gloves when taking each wipe sample.
5.4.2. Moisten the wipe filters with deionized water prior to use.
5.4.3. If possible, wipe a surface area covering 100 cm2.
5.4.4. Fold the wipe sample with the exposed side in.
5.4.5. Transfer the wipe sample into a 20-mL scintillation vial and seal
with vinyl or electrical tape. Securely wrap an OSHA-21
seal length-wise from vial top to bottom.
5.5.1. Document the operation sampled and
record other chemical substances in use.
5.5.2. Request fluoride analysis. Also request hydrogen fluoride
analysis if the impregnated backup pad was used. For smear tabs, only
total particulate fluoride will be analyzed and reported.
5.5.3. Submit at least one blank sample with each set of air or wipe
samples. The blank sample should be handled in the same manner as the
other samples except that an actual sample is not taken.
5.5.4. Ship the samples to the laboratory for analysis as soon as
possible in a suitable container designed to prevent damage in transit.
6.1. Safety Precautions
6.1.1. All work with concentrated acids or
bases is potentially hazardous. Always wear safety glasses and
protective clothing. HF and fluoride salts pose a particular hazard. All safety materials must be reviewed before handling either chemical.
6.1.2. Prepare all fusions in an exhaust hood.
6.1.3. Care should be exercised when handling any acidic or basic
solutions. If any acid or base contacts the eyes, skin, or clothes,
flush the area immediately with copious amounts of water. Medical
treatment may be necessary. Acid or base contact with work surfaces
should be avoided. Fluoride safety kits should be located near the fluoride work station. Instructions must be carefully followed.
6.1.4. Use a pipet bulb, never pipet by mouth.
6.1.5. Before using any instrument, the operator should consult the
Standard Operating Procedure (SOP) (8.5.) and any instrument manuals.
6.2.1. Ion Specific Electrode (ISE) and filling
solution, fluoride (Model 96-09, Orion Research Inc.,
6.3. Reagents (All chemicals should be reagent
grade or better)
6.2.2. Electrode, pH and filling solution (Model 81-02 RossTM
Combination pH electrode, Orion Research Inc.).
6.2.3. Reference electrode and filling solution (Model 90-01, Orion
6.2.4. Millivolt/pH meter, capable of relative mV, pH, standard addition
or concentration measurements (Model EA 940 Expandable Ionanalyzer,
Orion Research Inc.).
6.2.5. Stirrer, electronic, or magnetic with Teflon stirring bars.
6.2.6. Drying oven, vacuum-assisted (Model 5851, National Appliance Co.,
6.2.7. Nickel or monel crucibles, 75-mL.
6.2.8. Laboratory glassware including 25-, 250-, 500-, and 1,000-mL
volumetric flasks, and various sizes of Class A volumetric pipets, 20-mL glass scintillation vials.
6.2.9. Polyethylene centrifuge tubes, 50-mL.
6.2.12. Eyedroppers or disposable Pasteur pipets.
6.2.13. Automatic pipets, adjustable, 0.1- to 5.0-mL range (models
P-1000 and P-5000, Rainin Instruments Co., Woburn,
6.2.14.Analytical balance (0.01 mg).
6.3.1. Deionized water (DI H2O).
6.4. Standard Preparation
6.3.2. Sodium hydroxide (NaOH) pellets.
6.3.3. Sodium hydroxide, 5 N: Dissolve 200 g NaOH pellets in
approximately 600 mL of DI H2O and dilute to 1-L.
Store in a polyethylene bottle.
6.3.4. Sodium hydroxide, dilute: 0.5 and 0.05 N for pH adjustments.
6.3.5. Sodium fluoride (NaF).
6.3.6. Sodium fluoride stock solution, 1,000 µg/mL as F¯: Dissolve
1.10525 g NaF in DI H2O and dilute to 500 mL. Store
in a polyethylene bottle.
6.3.7. Tris(hydroxymethyl)aminomethane [(CH2OH)3CNH2].
6.3.8. Hydrochloric acid (HCl), concentrated (36.5 to 38% w/w).
6.3.9. Hydrochloric acid, dilute (2%) for pH adjustments.
6.3.10. Sodium tartrate (Na2C4H4O6·
6.3.11. Tris-Tartrate (T-T) buffer (concentrated): To approximately
500 mL DI H2O add 84 mL of concentrated HCl, 242 g
tris(hydroxymethyl)aminomethane and 230 g sodium tartrate. Stir to
dissolve and let cool to room temperature. Dilute to 1-L
with DI H2O. Use this concentrated solution to prepare dilute
T-T buffer. Do not use concentrated T-T buffer in any
samples or standards.
6.3.12. Tris-Tartrate (T-T) buffer (analytical): Dilute 360 mL of
concentrated T-T buffer to 2-L with DI H2O. Use
this buffer with an equal volume of sample or standard solution for
6.3.13. 1:1 T-T buffer/DI H2O (for dilutions only): Dilute
equal volumes of analytical T-T buffer with DI H2O.
Use this buffer only for sample dilutions
(i.e. when the sample displays an mV reading above the largest
6.3.14. Buffer solutions, in the range of pH 4 to 10.
Prepare dilutions of the 1,000 µg/mL F¯ stock standard. Use DI H2O
as the diluent and store all standards in polyethylene bottles. An example
of preparation of three standards in the analytical working range is
||Dilution of 1,000 µg/mL Stock
||20 mL to 250 mL
||20 mL to 500 mL
||5 mL to 1,000 mL
|Prepare 20 mL of each standard with 1:1 tris(hydroxymethyl)aminomethane:sodium tartrate added before analysis.
6.5. Sample Preparation
6.5.1. Rinse all glassware and crucibles with
10% HNO3 and DI H2O. Rinse all plasticware with DI
H2O. Allow labware to air dry before using.
6.5.2. MCE filters
Prepare filters (also wipe smear tabs) suspected of containing
particulate fluoride as follows:
- Carefully remove each filter from its cassette using a forceps.
Place each filter in a separate, labeled 75-mL nickel or monel crucible. Record the crucible number in a log book next to the
appropriate sample number. Using an automatic or glass volumetric
pipet, carefully add 5 mL of 5 N NaOH to each crucible.
- Turn on the vacuum-assisted drying oven. Place the heat setting at 90 °C and ramp the temperature slowly to 140 °C to avoid splatter and loss of sample. Maintain a drying temperature of 140 °C (Note: For the equipment
mentioned in Section 6.2.6., 140 °C is approximately 85% of the
maximum setting). Place the samples on a metal tray and secure with
tape to prevent the crucibles from "walking" off the surface due to
vibration. Place the tray containing the samples on the bottom of the
drying oven. Close the oven door tightly and dry for 1 h at 140 °C.
- Before proceeding, make sure the drying oven air vents are open to
the surrounding atmosphere. Turn on the vacuum to the drying oven and
then close the vents. Continue drying with the vacuum on for an
additional hour. When drying is complete, open the oven air vents.
When the vacuum reaches 10 mmHg or less, close off the vacuum. Open
the oven door when the internal oven pressure is equal to ambient
atmospheric pressure. Carefully remove the tray of samples and turn
off the oven.
- Place dried samples in a desiccator until the next step (5) is
performed, since the samples will reabsorb moisture from the air if there is a time gap between removal from oven and fusing process.
- In an exhaust hood, fuse the samples with the added NaOH by
carefully heating the crucible over a Bunsen burner and slowly
swirling the molten NaOH around the inside of the crucible until the bubbles subside. Samples will appear translucent.
||If splattering occurs, you have probably lost some of the sample and the results will be low. Place the crucibles back into the oven for more complete drying.
- Allow the samples to cool, then add 10 mL DI H2O to
- Carefully add 1.5 to 2 mL of concentrated HCl to neutralize the
- Quantitatively transfer the contents of each crucible into
separate 50-mL centrifuge tubes.
||The MCE filter should always be prepared and
analyzed even if the industrial hygienist specifies only an HF
analysis. See Section 7.3. for more details.
Place each impregnated backup pad into a clean scintillation vial and add 20 mL of DI H2O. Allow the pads to desorb for
at least 1 h. Agitate each solution occasionally while desorbing.
6.6. Instrument Set-up
Follow the manufacturers' instructions or the SOP (8.5.) for operation of
the analytical instrument and electrodes. Use a battery-powered
or electronic stirrer with stirring bar to stir any sample or calibration
solution (Note: If a magnetic stir bar is used, make sure the bar does
not contact the electrodes).
6.6.1. Connect the pH electrode (and reference electrode, if
necessary) to the millivolt/pH meter. Calibrate the instrument using two
buffers in the pH 4 to 10 range.
6.6.2. Individually adjust the pH of each sample to within 5 to 10
using an eyedropper or Pasteur pipet with dilute HCl or NaOH as needed.
Dilute particulate fluoride samples to 25mL.
||Do not use a large amount of solution to adjust
the pH. A few drops should be sufficient. The desorbed solutions
from the backup pads normally should not need any adjustment to
achieve a pH within 4.5 to 10.5.
Rinse the electrode after each standard or sample measurement.
6.7. Analytical Procedure
6.6.3. While adjusting the pH of the samples, periodically check the
instrument for drift by measuring the pH buffers.
6.6.4. Connect the fluoride ISE and reference electrode leads to the
appropriate sites of the instrument, place the electrodes in a standard
solution, and allow to stabilize.
6.7.1. Prepare working standards immediately before analysis as
follows: Add 20 mL of dilute
T-T buffer to each polyethylene beaker. Depending on the size of
the sample set, prepare enough standards to analyze at the beginning,
during, and at the end of the analysis. A fresh standard should be
analyzed periodically throughout the analysis according to laboratory QC rules.
||The total microgram content of the three
standards is 2,000, 1,000, and 125 µg, respectively. Other standards
in this range may be used if desired.
6.7.2. Quantitatively transfer fused particulate centrifuge tube samples into 100-mL Griff beakers. Pipet
25 mL of the dilute T-T buffer into each empty centrifuge tube and then
transfer these rinses into each corresponding beaker. Pipet 15 mL of each HF sample into 50 mL beakers and add 15 mL T-T buffer solution.
6.7.3. Using the mV scale on the millivolt/pH meter, scan each sample
and compare the mV reading to the standards. Always rinse the ISE with
DI H2O. If any mV reading is lower (less
negative) than that of the highest standard, the sample is above the
calibration curve and therefore must be diluted.
6.7.4. If a sample appears to be greater than the PEL, the sample may be
split into two aliquots, which can be diluted and analyzed separately.
To decide whether a sample should be split for duplicate analyses,
estimate the concentration of the sample using data presented in the
Appendix. For example, if the sample mV reading is near the 1,000 µg
standard and the air volume of the sample is near 200 L, then the
estimated air concentration is about 5 mg/m3.
||This calculation is only an estimate - it does
not include blank corrections, Time Weighted Average calculations,
etc. and is offered only as a convenience to allow for duplicate
sample analyses. Final assessment of an overexposure is performed by
the industrial hygienist.
6.7.5. Sample dilutions
To estimate the approximate concentration of any samples above the
highest standard, apply the following rule: Doubling the concentration
of the analyte will change the initial mV reading (Eo) by
about 18 mV. Therefore, if the sample has an initial mV reading 18 mV
less than the initial mV reading of the prepared standard, it is twice
as concentrated as the standard. Similarly, a sample reading 36 mV lower
than the standard is four times as concentrated. For samples that are 18
mV or less below the highest standard, pipet a 25-mL
aliquot of the sample/T-T buffer mixture into a clean
beaker. Add 25 mL of 1:1 T-T buffer/DI H2O
(Section 6.3.13.). This results in a two-fold dilution that
now is within the analytical concentration range. If further dilutions
are necessary, repeat the two-fold dilutions until the
sample is in the range of the standards. Save the unanalyzed portion for
a duplicate analysis.
||The 1:1 T-T buffer/DI H2O used for
two-fold dilutions is necessary to maintain a constant
6.7.6. Place the fluoride and reference electrodes
into a standard solution. Allow the reading to stabilize and record the
reading. Remove the electrodes from the standard solution, rinse with DI
H2O. Analyze a different concentration standard
(usually a ten- to twenty-fold concentration difference)
and determine the slope from the two readings. Slope values using the
instruments specified in Section 6.2. of this method have been
approximately -56 to -59 mV.
||The fluoride ISE can be affected by changes in
temperature. Standards and samples should be at the same temperature
before analyzing. Fluctuations in the ambient temperature during
analysis can sometimes be compensated for by slope adjustment (see
reference 8.4. for further details).
6.7.7. If available, use a standard additions
program intrinsic within the instrument to calibrate and convert
readings directly to concentration values. If an automated program is
not available, record the mV reading prior to standard addition (Eo)
and after addition (Es). The "standard addition" is a
500-µL aliquot of the 1,000 µg/mL fluoride stock standard (Section
6.7.8. Analyze a sample or standard (Eo). Using a glass or
automatic pipet, add a 1,000 µg (as F¯) spike, and then take a final
reading (Es or concentration for automated programs). Follow
the SOP for the particular instrument (8.5.) or manufacturers'
guidelines. Analyze a standard in the concentration range of the samples
after every tenth sample and at the end of the analysis.
7.1. Determine the total g fluoride content of
each sample and blank using a concentration-response
(concentration units versus µg) linear regression curve if readings were
measured in concentration units.
If mV readings were taken, plot the mV readings using an appropriate
standard additions program. An example of equations used for standard
additions can be found in reference 8.6. or in ISE manuals.
||Recall that 25 mL of
dilute T-T buffer and 1 mL NaF spike is added to each standard and
sample. Since this volume is constant for all samples and standards,
the total µg content of each sample and standard can be calculated
after standard addition computation as:
fluoride = µg/mL fluoride × Solution Volume × Dilution Factor
|| Solution Volume
||Standard or sample volume (mL)
without the addition of T-T buffer and NaF spike.
|| Dilution Factor
||Factor from Section 6.7.5.
7.2. Each air sample is blank corrected and the concentration is then calculated to determine particulate
fluoride or hydrogen fluoride exposure using the following equations:
||µg Sample - µg
air Volume, L
µg Sample or Blank = From above calculation (Section 7.1.)
|ppm F =
||MV × (µg Sample -
Molecular Weight × Air Volume, L
| MV (Molar Volume)
||24.45 (25 °C and 760 mmHg)
| µg Sample or Blank
||From Section 7.1.
| Molecular Weight (F)
7.3. Reporting Results
||Problems have occurred concerning the
discrimination between particulate and hydrogen fluoride (See
references 8.3. and 8.7. for further details). Past studies (8.3.,
8.8.) have indicated that HF did not significantly react with the MCE
filter, styrene cassette, or an untreated backup pad before collection
on the chemically-treated backup pad; however, one study
(8.3.) did indicate the possibility of HF reacting with or being
absorbed by particulate on the MCE filter (especially if the
particulate is an adsorbent such as alumina which is common in
aluminum reduction operations). A recent study (8.7.) appears to
indicate some reactivity of HF with the sampling media components. Due
to the possibility of HF reacting with particulate on the MCE filter,
the potential for underestimating HF exposure exists. The total
fluoride exposure should be considered for industrial operations
having alumina or other adsorbents in the air during sampling. If
possible for TWA determinations, consecutive samples should be taken
over the workshift, not to exceed 1-h each. This should
minimize the amount of particulate on the MCE filter.
Results are reported to the industrial hygienist as follows:
For particulate fluoride (MCE filters), sample results are reported as
For chemically-treated backup pad or MFGB samples, results are reported as
ppm hydrogen fluoride.
8.1. Hawley, G.G.: The
Condensed Chemical Dictionary. 11th ed. New York: Van Nostrand
Reinhold Co., 1987.
8.2. Occupational Safety and Health Administration
Technical Center: OSHA Laboratory Quality
Control Division Data by B. Babcock, Salt Lake City, UT. 1990
8.3. Einfeld, W., and S.W. Horstman:
Investigation of a dual filter sampling method for gaseous and particulate
fluoride. Amer. Ind. Hyg. Assoc. J. 40:
8.4. Orion Research Incorporated:
Instruction Manual, Fluoride Electrodes, Model
94-09, Model 96-09. Cambridge, MA: Orion Research
8.5. Occupational Safety and Health Administration
Technical Center: Ion Specific Electrode
Standard Operating Procedure. Salt Lake City, UT. In progress
8.6. Occupational Safety and Health Administration
Analytical Laboratory: OSHA Manual of
Analytical Methods edited by R.G. Adler (Fluoride as F¯ and HF.
Method No. VI-3). Salt Lake City, UT. 1977.
8.7. Lorberau, C., and K.J. Mulligan: Problem
identified with NIOSH method 7902. Appl. Ind. Hyg. 3:
8.8. Laboratory Services, Worker's Compensation Board
of British Columbia: Hydrogen Fluoride in Air
(Analytical Method No. 0751). Vancouver, B.C., Canada: Worker's
Compensation Board of British Columbia, 1989.
Calculated mg/m3 values for F¯ or HF
||- - - - - - -
- - - - - - - - - - - - Concn - - - - - - - - - - - - - - - - - - -
|Air Vol (L)
|mg/m3 values are
based on the equation:
||GF × µg
||estimated reading obtained
||gravimetric factor (1 for
F¯, 1.05 for HF)
||2.5 mg/m3 F¯ and
3 ppm HF
|Conversion of mg/m3
HF to ppm values can be accomplished by multiplying the mg/m3
HF value by 1.222.