A56-11
AMERICAN WOOD PROTECTION ASSOCIATION STANDARD
© 2015 All Rights Reserved
STANDARD METHOD FOR THE DETERMINATION OF THE SPECIFIC
GRAVITY OF DISTILLATION FRACTIONS AND RESIDUE
Jurisdiction: AWPA Technical Committee P-5
Adopted in 2011, this standard was developed from AWPA Standard A1, Method 5.
This AWPA Standard is promulgated according to an open, consensus procedure. Using this standard in no way signifies standardization of a
chemical or wood protection system in AWPA Standard U1.
1.0 Scope:
1.1 This method is employed to determine the specific
gravities of the distillation fractions and residue of creosote
and creosote solution.
1.2. It is also suitable for determining the specific gravity of
quantities of oil-type preservatives too small to be
determined by the hydrometer method, Standard A55.
2.0 Summary:
2.1. This method is employed to determine the specific
gravities of the distillation fractions of creosote and creosote
solution using pycnometers.
2.2. This standard formerly listed as AWPA Standard A1
Method 5.
3.0 Safety Precautions: The collection, storage, handling
and disposal of all material should be done in accordance
with standard laboratory safety procedures. Not all general
safety concerns associated with this standard are addressed
here. It is therefore the responsibility of the user to establish
and follow appropriate good laboratory practices and general
safety precautions where applicable.
4.0 Apparatus:
4.1. Pycnometers:
(a) Gay-Lussac type, 10 ml and 25 ml capacity; or
(b) Hubbard-Carmick type, 25 ml capacity.
Note: Calibration of the pycnometer is not necessary prior
to making each determination. Dependent on usage, re-
calibration should be done at sufficient time intervals to
insure that the calibration is accurate. In case of dispute
calibration is mandatory.
4.2. ASTM Low Softening Point Thermometer having a
range of 2° to 80°C and conforming to the requirements for
Thermometer 15°C as prescribed in the specifications for
ASTM Thermometers (ASTM Designation: E 1).
4.3. Water bath capable of being maintained at 38.0° ±
0.1°C.
4.4. Suitable analytical balance.
5.0 Reagents: Not applicable.
6.0 General Method Procedures:
6.1. Fractions Entirely Liquid Below 38°C.
6.1.1. Carefully heat the fraction to a temperature below
38°C in a water bath or by direct heat with a heat resistant
ceramic board under the container until the distillation
fraction is entirely liquid. Fill the dry Gay-Lussac
pycnometer by means of a warm pipette or warm drawn-out
medicine dropper until the neck is about one-half full,
avoiding the inclusion of air bubbles. Insert the stopper with
a rotary motion to secure a firm seat, making sure no air is
entrapped.
6.1.2. Place the filled pycnometer in the water bath at 38.0°C
so that the top of the stopper is slightly above the water
level, and allow to remain for at least 30 minutes. All this
time the capillary tube should be completely filled with oil.
Carefully wipe off with soft absorbent paper any oil from the
top flat surface of the stopper while the pycnometer is still in
the water bath.
6.1.3. Remove the pycnometer from the water bath, immerse
its lower half momentarily in cold water, dry its surface and
weigh it to the nearest 0.001 g. Remove the stopper, refill
the pycnometer with liquid fraction, and repeat the
determination as described above until two successive
weighings agree within 0.010 g. Designate this weight W 2.
6.2. Fractions Containing Solids at or above 38°C.
6.2.1. Carefully heat the fraction in a water bath or by direct
heat with a fireproof board under the container until the
distillation fraction is entirely liquid. By means of a warm
pipette or warm drawn-out medicine dropper, transfer a
sufficient amount of the fraction to the dry Gay-Lussac or
Hubbard-Carmick pycnometer until it is approximately one-
half full, avoiding the inclusion of air bubbles and contact of
the oil with the ground glass surface of the neck of the
pycnometer. (Permitting the stream of liquid to impinge on
the side of the pycnometer below the ultimate liquid level
aids in preventing inclusion of air bubbles.)
6.2.2. Cool the pycnometer to room temperature and weigh
with the stopper. Designate this weight W 3. Add freshly
boiled distilled water to the partially filled pycnometer until
it is about three-quarters full.
6.2.3. Partially immerse the pycnometer without the stopper
in a small water bath, maintained at 90° to 95° C, and allow
it to remain until the fraction is liquid and free of air
bubbles. (Any entrapped air bubbles can be removed with a
heated fine wire loop.)
6.2.4. Cool the pycnometer and contents to a temperature of
about 25°C and then add cool, freshly boiled distilled water
until the neck is about one-half full. Insert the stopper with a
rotary motion to secure a firm seat, making sure that all air is
excluded. Completely immerse the pycnometer in the water
bath at 38.0°C and allow sufficient time for an equilibrium
crystal state to be established. One hour is usually sufficient.
- 278 -
A56-11
STANDARD METHOD FOR THE DETERMINATION OF THE SPECIFIC
GRAVITY OF DISTILLATION FRACTIONS AND RESIDUES
Page 2 of 2
© 2015
6.2.5. While still in the water bath, raise the pycnometer
until the top of the stopper is above the water level and wipe
off the water on the flat surface of the stopper with soft
absorbent paper, taking precautions not to remove water
from the capillary tube.
6.2.6. Remove the pycnometer from the water bath, immerse
its lower half momentarily in cold water, dry its surface and
weigh it to the nearest 0.001 g. Remove the stopper, add
freshly distilled water, reinsert the stopper, and return the
pycnometer to the water bath at 38.0°C. After 30 minutes,
remove and weigh the pycnometer as described above.
Repeat these operations until two successive weighings
agree within 0.010 g. Designate this weight W 4.
6.3. Distillation Residue.
6.3.1. Carefully heat the fraction to a temperature below
38°C in a water bath or by direct heat with a heat resistant
ceramic board under the container until the distillation
fraction is entirely liquid. Carry out the determination as
described in Procedure 6.2 above, using the Hubbard-
Carmick pycnometer.
7.0 Calculations:
7.1. Fractions Entirely Liquid Below 38°C.
Specific Gravity at 38.0/15.5C
W 2 P
W 1 P
Where, P = Weight of empty pycnometer
W1
W2
W3
= Weight of pycnometer full of water
= Weight of pycnometer full of liquid fraction
= Weight of pycnometer partially filled with solid
fraction or distillation residue
W4 = Weight of pycnometer full of solid fraction or residue
and water
0.99393 = The ratio of the density of water at 38.0°C to the
density of water at 15.5°C, i.e.,
0.99299
0.99905
8.0 Report: Report the specific gravity at 38.0°/15.5°C to
the nearest one thousandth unit of specific gravity.
9.0 Precision Statement:
9.1. The following criteria should be used to judge the
acceptability of results at the 95 percent probability level:
Repeatability. Duplicate values by the same operator should
not be considered suspect unless they differ by more than
0.005.
Reproducibility. The values reported by each of two
laboratories should not be considered suspect unless the
values differ by more than 0.010.
Standard Deviation. The estimated standard deviation of
repeatability is 0.0018 at 54 degrees of freedom. The
estimated standard deviation of reproducibility is 0.0036 at
27 degrees of freedom.
9.2. No precision statement based on ASTM E-691 has yet
been developed for this Standard.
x 0.99393
7.2. Fractions Containing Solids at 38° C and Distillation
Residue
SpecificGravityat 38.0/15.5C
W 2 P
(W 1 P)(W 4 W 3)