 Wildland
Fire Chemicals
Evaluation of Wildland Fire Chemicals
Standard Test Procedures
STP 4.4—pH
Summary:
The pH of wildland fire chemicals can be used as part of an assessment
of product stability over time as well as for quality assurance. In
addition pH of the water used to prepare some of the fire chemicals can
have a
significant impact on their physical characteristics.
Equipment:
- Electronic pH meter with combination electrode
- Standard buffer solutions—pH
4, pH 7, and pH 10
Method:
- 7 buffer solution.
- Ensure that the electrode is clean and thoroughly
rinsed with deionized water.
- Adjust the calibration knob
until the meter reads 7.0.
- Rinse the electrode thoroughly
with deionized
water and place in the test sample.
- Allow the reading
to stabilize.
- If the reading is in the range of pH 6.0
to 8.0, record the
reading and repeat the measurement with a second sample
of the test sample.
- If the reading is outside the range of
pH 6.0 to 8.0, repeat
the calibration with pH 7 buffer and then insert
the electrode into pH
4 or pH 10 buffer, depending on the preliminary reading,
until stabilized.
- Use the slope function to adjust
the meter reading
to pH 4 or
pH 10.
- Rinse the electrode thoroughly with
deionized water and place in the test sample.
- Allow
the reading to stabilize.
- Record the reading.
- Rinse
the electrode with
deionized water.
- Repeat the measurement with
a second sample of the
test material,
repeating steps 9 through 11.
- Rinse
the electrode thoroughly and replace in fresh storage solution.
References:
American Society for Testing and Materials. Standard Test Methods
for pH of Water; D1293-99(2005).
Printer-friendly (PDF
File, 60 kb)
 Click the icon on the left to download a free version of Adobe Acrobat Reader
|
Printer
friendly
