Coatings
&
is to ensure the contents remain cold enough to prevent
evaporation.
Are you developing environmentally-
sound coatings?
In recent years we have seen the elimination of mercury
compounds from polyurethane systems. We are also working
on eliminated hazardous solvents from our ancillary processes
such as flushing and cleaning.
While the majority of the materials themselves cannot be
altered too much, as this would have a significant impact on
their performance, our main environmental contribution lies
in the improved efficiency and reduced waste and fugitive
release of materials from our processes. This is brought about
by our drive towards increased automation.
What role do tapes and wraps have in
the coatings industry?
Tapes and wraps are generally interpreted as cold applied
coating materials such as petrolatum or wax tapes, though
included in this category are hot applied bituminous and
hot melt polymeric adhesive tapes that require the bonding
material to be heated to melting for application. They have
a significant role to play though their use is restricted to
pipelines with relatively low operating temperatures of up to
around 30˚C for the bituminous, petrolatum and wax types or
80˚C for the polymeric hot melt adhesive types.
These types of material are widely used for relatively
low volume coating projects where automation may not be
economically viable. They are used widely for rehabilitation
of pipeline coating and for restricted access working.
Other than coatings, how else can you
protect your pipeline from corrosion?
Corrosion protection on oil and gas pipelines is usually
provided by a combination of a coating primarily designed to
adhere to the steel thereby excluding water and oxygen from
the surface, and cathodic protection (CP) to provide further
assurance of corrosion protection should the coating become
damaged.
The anodic or corroding areas and the cathodic or
protected areas on a pipeline are commonly on the same
surface but separated microscopically. The coating system is
the primary barrier against environmental corrosion while the
CP system is a secondary defence to protect areas of the pipe
that become exposed due to scratched, missing or damaged
coating. CP is typically used to prevent corrosion at any weak
areas in the coating such as field joints or damaged spots.
Which coatings-related events, seminars
and/or standards would you
recommend?
PIH has been actively involved for many years in the
development and revision of the ISO 21809 series of standards
which cover the petroleum and natural gas industries —
external coatings for buried or submerged pipelines used in
pipeline transportation systems. The series is split into several
specific areas:
)
Part 1: polyolefin coatings (3-layer PE and 3-layer PP).
)
Part 2: fusion-bonded epoxy coatings.
)
Part 3: field joint coatings.
)
Part 4: polyethylene coatings (2-layer PE).
)
Part 5: external concrete coatings.
)
In preperation are part 6: dealing with bitumen, asphalt
and coaltar coatings; part 7: dealing with liquid coatings;
part 8: dealing with thermal insulation coatings; and part 9:
dealing with epoxy polyamide powder coatings (2-layer)
are in reparation.
Additionally, ISO 12736 deals with wet insulation coatings
for oil and gas pipelines.
Craig J R Thomas
, Product
Manager - Pipeline Coatings,
Jotun A/S, UAE
Has the way you coat pipes changed
in the last ten years? How?
Coating technology has changed over the last decade.
There is a definite trend towards greater use of high
operating temperature (HOT), fusion-bonded epoxy (FBE)
coatings and dual-layer FBE coating systems that provide
a very specific level of topcoat performance. Surface
roughness associated with internal flow coatings is also
becoming more prevalent in specifications, but such a
specification parameter needs to be handled with care.
In the pipeline industry, track record and conformance
to both local and international approvals provide
confidence in the product – whether powder or liquid –
where the consequences associated with failure can be
high. Radical changes to pipe coating products are not
always seen in a positive light by end users, designers and
even pipe coaters, unless they are required to fulfil a very
specific need, where no existing solution exists. The reason
is quite simple – new means change, new means no track
record, new means re-approval.
Most pipe coating manufacturers have realised that the
‘standard’ line pipe coating market allows for huge volume
potential and have adapted existing products to meet the
required standards and approvals. Starting to develop a
brand new product can be very time consuming and not
always cost-effective. Moreover, if the industry has not
49
