operator has virtually no chance of making a mistake.
Category 1 systems may, as per the standard, only be used for a
fully attended operation.
Category 2
Category 2 systems have the ability to transmit level and alarm
information to a centralised control room. But the alarm is
dependent so that an ATG failure can cause total loss of
information about the tank levels as well as the alarms.
Category 2 systems have no redundancy and should only be
used if the failure rate of the ATG and level system is
extremely low (i.e. the best possible technology available).
Category 2 is permitted only for attended and semi attended
facilities. While most tank facilities are fitted with Category 2
systems, most are also fitted with unreliable automatic tank
gauges making these particularly vulnerable to an overfill
event.
Category 3
Category 3 systems are like Category 2 systems but are
characterised by having an independent alarm. The
independent alarm ensures that an ATG failure will not cause a
failure of the alarm function. Category 3 systems are
considered the best available configuration and technology for
tank filling operations and alarm systems. They may be used at
a facility which is attended, semiattended or unattended. A
Category 3 tank allows for better tank utilisation as a higher
working level can be used.
Basically any modern tank farm will be classified as a
Category 3 facility, which shall be equipped with (at a
minimum):
n
n
1x automatic tank gauge (ATG).
n
n
1x independent overfill prevention system (OPS).
The API 2350 standard includes all the requirements for
implementing Category 3 tank operations.
Automatic overfill prevention
systems
The API 2350 recognises that technology is advancing and that
better devices are available today than ever before. The
standard thus allows for further automation by utilising an
Figure 3.
Dual radar gauges for level and overfill
measurements. SIL2 or SIL3 safety certified.
Flottweg SE • Industriestraße 6-8 • 84137 Vilsbiburg • Germany • Tel.: +49 8741 301-0 • Fax: +49 8741 301-300 •
•
FLOTTWEG TECHNOLOGY FOR OIL RECOVERY
FROM RESIDUALS DURING TANK CLEANING
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The solid can be sent to landfill, as well as being
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significant environmental hazard
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Automatic and continuous operation even when
the oil sludge has a fluctuating composition
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Explosion-proof zone 1 or zone 2
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FLO-15022_Anz Tankreinigung_210 x 147 + 3 mm Bleed 04.02.15 10:14 Seite 1
