SECTION IV
4.0
REQUIRED CONDITIONS AND RECOMMENDATIONS FOR SAFE USAGE:
The attention of the user of this apparatus is drawn to the possible hazards of oxygen sensing
within flammable environments normally found above confined petroleum liquids, which are
known to be generators of static electricity, and which are not covered with an inert gas blanket.
The following is a general guidance to safe usage, drawn from the advice and experience of
various industry sources.
The specific safety standards or directives of your company are to be strictly adhered to, with the
general guidance given here being regarded as only a supplement to existing and established
operating safety procedures.
4.1
REQUIRED CONDITIONS:
The oxygen sensor frame and reel assembly are to be earthed (grounded) to the liquid
tank containment vessel or tank, before and during introduction of the gauging equipment
into the vessel. The earthing conductor must not be disconnected until the equipment is
completely withdrawn from the vessel being gauged. A coiled grounding cable with a
heavy alligator spring clamp is provided with the equipment. Proper grounding of this
cable is the responsibility of the user.
4.2
RECOMMENDED SAFE USAGE CONDITIONS:
4.2.1 The apparatus’ sensor should preferable be entered into a tank or vessel within an
earthed sounding tube or pipe where such devices are provided and are normally
used for temperature and/or other fluid measurements.
4.2.2 For sea going vessels where gauging is normally accomplished through standard
cargo tank ullaging hatch ports or other approved means, the following
precautions should be observed.
4.2.3 Sensor entry into tanks or vessels immediately following a tank filling or loading
operation of known static accumulator type petroleum products or other
flammable liquids,
should not
be attempted until, at least a period of
30 minutes
has elapsed since the cessation of filling.
4.2.4 Clean oil distillates are, in general, known to be accumulators of static electricity
due to their low conductivity (i.e., less than 1000 picosiemens/meter) and
therefore may require relaxation periods greater than 30 minutes before gauging is
attempted. The foregoing does not consider use of anti-static additives to clean
oils, as generally easing the need for proper precaution, unless actual and specific
product testing has shown the product to have conductivity levels which eliminate
the danger of static charging.
4.2.5 The presence of an inert gas blanket above products of this type may generally
relax the above precautions. However, such determination is to be made by
qualified authorities.
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