35 Ill. Adm. Code 218.128
Monitoring VOL Operations
Section 218
Section 218.128 Monitoring
VOL Operations
a) Except as provided in subsection (d), the owner or operator of
each storage vessel with a design capacity greater than or equal to 40,000
gallons storing a liquid with a maximum true vapor pressure that is normally
less than 0.75 psia shall notify the Agency within 30 days when the maximum
true vapor pressure of the liquid exceeds 0.75 psia.
b) Available data on the storage temperature may be used to
determine the maximum true vapor pressure.
1) For vessels operated above or below ambient temperatures, the
maximum true vapor pressure is calculated based upon the highest expected
calendar-month average of the storage temperature. For vessels operated at
ambient temperatures, the maximum true vapor pressure is calculated based upon
the maximum local monthly average ambient temperature as reported by the
National Weather Service.
2) For other liquids, the vapor pressure:
A) Determined by ASTM Method D 879-83, incorporated by reference
at Section 218.112(a) of this Part;
B) Measured by an appropriate method approved by the Agency and
USEPA; or
C) Calculated by an appropriate method approved by the Agency and
USEPA.
c) The owner or operator of each vessel storing a mixture of
indeterminate or variable composition shall be subject to the following:
1) Prior to the initial filling of the vessel, the maximum true
vapor pressure for the range of anticipated liquid compositions to be stored
will be determined using the methods described in subsection (b).
2) For vessels in which the vapor pressure of the anticipated
liquid composition is 0.5 psia or greater but less than 0.75 psia, an initial
physical test of the vapor pressure is required; a physical test at least once
every 6 months thereafter is required as determined by the following methods:
A) ASTM Method D 2879-83, incorporated by reference at Section 218.112(a)
of this Part;
B) ASTM Method D 323-08, incorporated by reference at Section 218.112(a)
of this Part; or
C) As measured by an appropriate method approved by the Agency.
d) The owner or operator of each vessel equipped with a closed
vent system and control device meeting the specifications of Section 218.120 of
this Subpart is exempt from the requirements of subsections (a) and (b).