Current through Register Vol. 60, No. 12, December 1, 2021
An owner and permittee may use manual
tank gauging as a release detection method for USTs that are less than 2,001
gallons in size.
(a) For USTs of 550 gallons
or less nominal capacity and USTs with a nominal capacity of 551 to 1,000
gallons that meet the tank diameter criteria in the table may use this as the
sole method of release detection.
For USTs of 551 to 2,000 gallons in size,
this method may be used instead of manual inventory control (OAR 340-150-0430).
This method is allowed for a period of:
Ten years after the installation of the UST system; or
(B) Ten years after the UST system achieved
compliance with corrosion protection requirements; except
(C) In no case may manual tank gauging be
used as a primary release detection method after December 22, 2008.
(c) After the period of use has
expired as listed in paragraph (1)(b)(C) of this section, an owner and
permittee of an UST between 551 and 2,000 gallons in size must use one of the
release detection methods in OAR 340-150-0435 through 340-150-0470.
An owner and permittee must
use the following procedures for the manual tank gauging release detection
(a) Tank liquid level measurements
must be taken at the beginning and ending of a minimum 36-hour test period,
during which time no liquid (i.e., regulated substance) may be added to or
removed from the UST;
measurements must be based on an average of two consecutive measuring stick or
automatic tank gauge readings at both the beginning and ending of the period in
which the UST is tested; and
The equipment used to measure the level of regulated substance in the UST
(e.g., stick or automatic tank gauge) must be capable of measuring the level of
the regulated substance over the full range of the UST's height to the nearest
one-eighth of an inch.
(3) An owner and permittee must monitor the
UST system for releases at least weekly and record and reconcile the results of
each week's readings for each month.
(4) In addition to any other requirements of
this rule, an owner and permittee must conduct tightness testing (OAR
340-150-0445) of USTs of 1,001 to 2,000 gallons in size at least once every
(5) An owner and
permittee must report to DEQ any variation between beginning and ending
measurements that exceeds either the weekly or monthly standards in the table
in 340-150-0440(1)(a) within 24 hours as a suspected release (OAR 340-150-0500)
and immediately begin investigation as 340-150-0510 specifies.
(6) An owner and permittee must immediately
investigate all larger-than-normal or reoccurring variations in results and
report such variations to DEQ as a suspected release if the variation cannot be
accounted for, without waiting to obtain a second week of data.
(7) An owner and permittee must retain at a
minimum the most current 12 consecutive months of release detection records and
the last two tightness test results.