| If
Specialist Industrial Coatings are not the contractor, we
can offer an independent inspection service. If we
are the contractor, our internal quality control is to the
same high standards. |
 |
|
Corrosion
problems in Industry, Shipping and Civil Engineering make
corrosion control an essential consideration in the fabrication
of steel. Overall costs and coating performance are two
prime factors to be considered and it has been well established
that they are closely related, providing the coating system
has been applied to specific rigid standards. In other words,
no matter how good a coating system is, it is only as good
as the technical expertise with which the surface preparation
and the coating application has been carried out.
Specialist
Industrial Coatings offer an inspection service which has
gained considerable experience over the last thirty years
with the painting of steel and attempting to prevent corrosion
generally of both internal and external structures. Specialist
Industrial Coatings Ltd offer a coating Inspection Service
that was one of the first to receive the coveted ISO 9002
Accreditation standard for Quality Management Systems. |
| Our
surface coating inspection service is a natural corollary
to other work done in this field and we feel there is no other
really satisfactory method of tackling the problem. We consider
that such a service must be independent both of the contractor
and the paint manufacturer, as being Independent gives our
Inspectors full authority to obtain the required standards
of specification. |
| Introduction |
|
The
duties of a Coating Inspector are primarily to ensure that
the surface preparation and coating application to blast
cleaned steel are to the Clients specification. A
multitude of factors can affect the proper application of
a coating system, therefore the Inspectors duties
cover a broad spectrum of the site activities.
Since
no blasting and coating can be carried out without his supervision,
the Inspector will work as required, but if the work-load
becomes unreasonably demanding, further personnel will be
available to provide an inspection service on a 24
hour per day, seven days per week basis. Our Coating Inspectors
are men of proven integrity and technical competence, and
are familiar with all types of paint spraying and grit blasting
equipment. In order to attain the desired standards,
they are capable of demonstrating their operation. Extensive
training of our Inspectors has ensured that they have reached
a uniform standard of competence which means that they can
be interchanged with no decrease in inspection standards.
Broadly
speaking the Inspectors duties are divided into three
sections:
|
| INITIAL
APPRAISAL |
|
SITE
OPERATIONS |
|
DOCUMENTATION
|
|
| Initial
Appraisal |
 |
|
On
arrival at the site the Inspector will establish lines of
communication with the Client, the Contractor and with Specialist
Industrial Coatings Inspection Services Head Office for
the submission of reports and routine records.
The Inspectors
first objective is to ensure that the equipment to be used
is in working order and is in accordance with the Clients
and the Paint Manufacturers specification. If necessary
he will advise on modification, alteration or repair of
any defective equipment and the purchasing of any replacement
items. |
- Blasting
equipment (manual or automatic):
Blast kettles, hoses, nozzles, connections, water separators
etc.
- Compressed
Air:
Quantity available, maximum pressure available at blast
nozzle, water and oil separators.
- Abrasive:
Handling, removal, cleaning, drying.
- Temperature
Control:
Heating and drying equipment.
- Dehumidification:
Relative humidity readings taken. Dew point calculated.
- Paint Spray
Equipment:
Spray nozzles, tip sizes, mixers, hoses, water traps
etc.
- Scaffolding
Rigging Staging
- Shelters
or covers
- Lighting
- General,
blasting, inspection spotlight
|
| A
representative sample of the abrasive to be used on-site
is despatched to our Company office for analysis.
The
coating material to be applied will be checked against the
specification, the quantity present noted and any forward
ordering put in hand. The Coating Inspector will make a
discreet assessment of the technical ability of the personnel
to be involved in the blasting and coating operations by
staging a full scale dummy run, which will familiarise
the operators with the standards demanded in the blast cleaning
and coating application.
The
first stage will be fully documented in the Initial Appraisal
Report.
|
|
|
|
|
|
| Site
Operations |
 |
|
Prior
to blast cleaning, the Inspector will examine the initial
preparation of the steel to check for weld spatter in the
case of prefabricated sections and will ensure that all
sharp corners and edges have been rounded off. Any laminations
which are obvious at this stage will be brought to the attention
of the Site Engineer or Steel Superintendent for his consideration.
After the blast
cleaning has commenced, the Coating Inspector will make
regular examinations of all blast cleaned steel to assess
whether the standard of cleanliness required in the specification
is being obtained, and to ensure that the maximum cleaning
rate and efficiency is being achieved - but he will not
cause undue delays by doing so. Once the job is progressing
smoothly and an efficient work method has been established,
the Coating Inspector will examine cleaned surfaces whenever
the blasting foreman feels that the overall condition of
the steel section being blasted will be of a standard acceptable
to the Inspector. |
| When
the Inspector has satisfied himself by means of visual survey,
that the blast cleaned steel surface is of the specified standard,
he will, if he deems it necessary, measure the surface roughness
using an Elcometer Surface Profile Gauge or Testex Tape, the
latter giving a permanent record of surface conditions. These
measurements are used as a periodic check on surface profile,
which is itself an indication as to the physical condition
of the abrasive being used. |
| In
polluted industrial environments checks for soluble iron
in the forms of chloride or sulphate can be carried out
to assess the degree of steel contamination. Similarly,
copper sulphide tests can be carried out to determine trace
quantities of millscale remaining on the surface of new
steel after blast cleaning. |
|
 |
| Before
application of the coating, the Inspector must verify that
the climatic conditions are within the specified limit.
This is carried
out using properly calibrated electronic or traditional
instrumentation to determine substrate temperature and relative
humidity / dew point. |
| Relative
Humidity:
This figure is obtained by means of a Whirling or digital
Hygrometer and is converted into Dew Point.
Steel Temperature:
This is measured by a magnetic adhering thermometer
in ° C.
Specialist Industrial
Coatings Ltd Inspection Services have supervised and inspected
many projects utilising the new generation of surface tolerant
coatings. We are therefore very experienced in assessment
of the lower grades of preparation that can be allowed for
atmospheric exposure conditions.
We also liase
with the coating manufacturers on behalf of our clients,
to enable optimum use and performance from the specialised
systems available.
No painting will
take place if the Steel Temperature is equal to or less
than the Dew Point because when the Steel Temperature is
less than the Dew Point water vapour condenses on the Steel
Surface. Ideally, the cleaned steel should be coated immediately
after blast cleaning and the Coating Inspector must strike
a fine balance between producing too much cleaned steel
and too little. Too little could result in not meeting target
dates, on the other hand too much could mean that all the
coating could not be applied before the steel had turned,
resulting in the need for reblasting which could cause even
more delay. |
 |
|
The
Coating Inspector will ensure that there is sufficient material
on hand to coat any blast cleaned steel. If the paint has
had to be mixed, as in the case of a two pack coating system,
he will have observed the mixing of the paint for the planned
application so that the paint is all applied within the specified
pot life. The inspector will remain on site until all blast
cleaned steel has been coated. |
| The
problems of application and spray techniques should have
been solved during the dummy run, (see Initial
Appraisal) but the Inspector should observe the first few
spray passes and correct any faults in application. When
the spray operator has mastered the application he will
be allowed to operate without direct supervision, the Coating
Inspector making visual inspections and taking wet film
thickness measurements from time to time.
When sufficient
area has been covered to make the calculations significant
the Inspector will estimate spreading rate, paint consumption
and the quantity of material required to finish the job.
He will indicate holidays and areas of too thin
coating and ask for these defects to be made good.
The drying and
curing times will be checked by the Inspector using the
solvent rag test as a guide where applicable,
and he will ensure that the inter-coat time intervals are
observed and that the surface is in a condition to receive
the subsequent coats of the paint system. Contamination
of paintwork by oil, dust and moisture between coats must
be avoided at all costs. |
| Shop-primed
prefabricated steel sections, blast cleaned automatically
or manually and coated with wash-type primers, red oxide
epoxies and zinc epoxies, pose their own specialised problems
in the application of subsequent coating systems. SICL Coating
Inspectors will advise on the preparation of weathered shop-primed
steel, which has accumulated rust from damage caused by
fairing, welding and physical damage sustained during storage
and transportation. |
|
 |
| During
mixing and spraying operations the Inspector will ensure
that fire safety precautions are observed and that there
will be no build up of inflammable vapours in enclosed spaces.
When the coating
has dried or fully cured the Dry Film Thickness will be
measured and, where specified, the incidence of holidays
in the coating and its adhesion to the steelwork will be
measured by using an Elcometer Adhesion tester or cross
hatch test.
The Inspector
will decide when a section of coated steel has cured sufficiently
to be handled without causing damage to the coating and
will ensure that when it is handled great care it taken
to prevent damage.
The work of actual
inspection finishes at this point and is followed by the
equally important phase of report writing and documentation. |
| Documentation
/ click to continue... |
| |
|
|
|
|