خطوات اعادة تاهيل خزانات البترول الموجودة على ناقلات البترول بالبحر الاحمر-الكيماويات المختارة -(الحديد الكربونى)

Tankguard Storage

THE CHEMICAL-DESCRIPTION

Product description

This is a two component polyamine cured novolac epoxy coating. It is a specially designed tank lining with excellent chemical resistance.

Can be used as primer, mid coat or finish coat in atmospheric and immersed environments.

Suitable for properly prepared carbon steel, galvanised steel, stainless steel and concrete substrates.

Technical Data735;739 1 735

Scope

The Application Guide offers product details and recommended practices for the use of this product.

The Application Guide (AG) must be read in conjunction with the relevant specification, Technical Data Sheet(TDS) and Safety Data Sheet (SDS) for all the products used as part of the coating system.

Referred standards

Reference is generally made to ISO Standards. When using standards from other regions it is recommended to reference only one corresponding standard for the substrate being treated.

Surface preparation and coating should normally be commenced only after all welding, degreasing, removal of sharp edges, weld spatter and treatment of welds is complete.

It is important that all hot work is completed before coating commences.

The required quality of surface preparation can vary depending on the area of use, expected durability and if applicable, project specification.

Surface preparation

The required quality of surface preparation can vary depending on the area of use, expected durability and if applicable, project specification.

When preparing new surfaces, maintaining already coated surfaces or aged coatings it is necessary to remove all contamination that can interfere with coating adhesion, and prepare a sound substrate for the subsequent product.

Inspect the surface for hydrocarbon and other contamination and if present, remove with an alkaline detergent.

Agitate the surface to activate the cleaner and before it dries, wash the treated area using fresh water.

Paint solvents (thinners) shall not be used for general degreasing or preparation of the surface for painting due to the risk of spreading dissolved hydrocarbon contamination.

Paint thinners can be used to treat small localized areas of contamination such as marks from marker pens.

Use clean, white cotton cloths that are turned and replaced often.

Do not bundle used solvent saturated cloths.

Place used cloths into water.

When the surface is an existing coating, verify with technical data sheet and application guide of the involved products, both over coatability and the given maximum over coating interval.

Process sequence

Surface preparation and coating should normally be commenced only after all welding, degreasing, removal of sharp edges, weld spatter and treatment of welds is complete.

It is important that all hot work is completed before coating commences.

Soluble salts removal

Soluble salts have a negative impact on the coating systems performance, especially when immersed.

general recommendations for maximum soluble salts (sampled and measured as per ISO 8502-6 and -9) content on a surface are:

Chemical tanks:

50 mg/m² For areas exposed to (ISO12944-2):

C1-C4: 200 mg/m²

C5M or C5I: 100 mg/m²

Im1-Im3: 80 mg/m²

Carbon steel

Initial rust grade

The steel shall preferably be Rust Grade A or B (ISO 8501-1).

It is technically possible to apply the coating to grades higher than B, but it is practically challenging to ensure specified film thickness on such a rough surface, hence risk of reduced lifetime of the coating system.

When steel of Rust Grade C or D is coated, the frequency of inspection and testing should be increased.

When preparing new surfaces, maintaining already coated surfaces or aged coatings it is necessary to remove all contamination that can interfere with coating adhesion, and prepare a sound substrate for the subsequent product.

Inspect the surface for hydrocarbon and other contamination and if present, remove with an alkaline detergent.

Agitate the surface to activate the cleaner and before it dries, wash the treated area using fresh water.

Paint solvents (thinners) shall not be used for general degreasing or preparation of the surface for painting due to the risk of spreading dissolved hydrocarbon contamination.

Paint thinners can be used to treat small localized areas of contamination such as marks from marker pens.

Use clean, white cotton cloths that are turned and replaced often. Do not bundle used solvent saturated cloths.

Place used cloths into water.

When the surface is an existing coating, verify with technical data sheet and application guide of the involved products, both over coatability and the given maximum over coating interval.

Metal finishing

For areas in corrosivity category C1 to C4 (ISO 12944-2) all irregularities, burrs, slivers, slag and spatter on welds, sharp edges and corners shall conform to minimum grade P2 (ISO 8501-3) Table 1, or as specified.

All edges shall have a rounded radius of minimum 2 mm subjected to three pass grinding or equally effective method.

For areas in corrosivity category C5, Im1-3 the requirement is for the steel to conform to grade P2 (ISO 8501-3).

All edges shall have a rounded radius of minimum 2mm subjected to three pass grinding or equally effective method.

One may use a mechanical grinder fitted with a suitable abrasive disc.

All sharp irregularities, burrs, slivers, slag and spatter on welds, whether apparent before or after blast cleaning, shall be removed before coating application.

It is recommended that welding smoke should be removed by low-pressure Water Cleaning LP WC method (ISO 8501-4:2006) Wa1 using fresh water.

Welding smoke residues are water soluble and could cause blistering if not removed by washing before blasting.

Defective welds shall be replaced and treated to an acceptable finish before painting.

Temporary welds and brackets shall be ground to a flat finish after removal from the parent metal.

Surface preparation and coating should normally be commenced only after all metal finishing and degreasing of a specific area is complete.

It is important as much hot work as possible is completed before coating commences.

Pitting repair

Pittings in steel can be difficult to cover fully with most coatings.

In some areas it is practically feasible to use filler to fill pittings.

This should then be done either after the initial surface preparation or after application of first coat.

For tank coating and lining used for chemical exposure the recommendation is to fill pitts through welding, since using fillers may negatively affect the coating systems' chemical resistance and flexibility.

Abrasive blast cleaning

Application of protective coating shall commence before degradation of the surface standard occurs.

Cleanliness

After pre-treatment is complete, the surface shall be dry abrasive blast cleaned to Sa 2½ (ISO 8501-1) using abrasive media suitable to achieve a sharp and angular surface profile.

Surface profile

Recommended surface profile 50-85 μm, grade Medium G; Ry5 (ISO 8503- 2).

Measure the achieved profile with surface replication tape (Testex) (ISO 8503-5) or by surface roughness stylus instrument (ISO 8503-4).

Abrasive media quality

The selected abrasive must be compatible with both the surface to be blast cleaned and the specified coating system.

The abrasive shall meet specifications as per relevant parts of ISO 11124 (Specification for metallic blast-cleaning abrasives), or ISO 11126 (Specification for non-metallic blast- cleaning abrasives). It should be sampled and tested as per relevant parts of ISO 11125 (metallic abrasives) or ISO 11127 (non-metallic abrasives).

Dry storage of abrasive and shelter for blasting pots is necessary to prevent equipment becoming clogged with damp abrasive.

All abrasive blast media used should be new and not recirculated, with the exception of Steel Grit.

If this is utilized the circulation process must include a cleaning process.

Compressed air quality

The supply of clean air to blasting pots must be secured to avoid contamination of abrasive and thereby of blast cleaned surfaces.

Compressors must be fitted with sufficient traps for oil and water.

It is also recommended to fit two water separators at the blasting machine to ensure a supply of moisture-free air to the abrasive chamber.

Dust contamination

At the completion of abrasive blasting the prepared surface shall be cleaned to remove residues of corrosion product and abrasive media and inspected for surface particulate contamination.

Maximum contamination level is rating 1 (ISO 8502-3).

Dust size no greater than class 2.

Hand and Power Tool Cleaning

Power tool cleaning

Minor damage of the coating may be prepared to St 3 (ISO 8501-1).

Suitable method is disc grinding with rough discs only.

Ensure the surface is free from mill scale, residual corrosion, failed coating and is suitable for painting.

The surface should appear rough and mat.

Overlapping zones to intact coating shall have all leading edges feathered back by sanding methods to remove all sharp leading edges and establish a smooth transition from

the exposed substrate to the surrounding coating.

Consecutive layers of coating shall be feathered to expose each layer and new coating shall always overlap to an abraded existing layer.

Abrade intact coatings around the damaged areas for a minimum 100 mm to ensure a mat, rough surface profile, suitable for over coating.

Mechanical repairs are only accepted for minor areas of damage where abrasive blasting is expected to create more damage to the coating system than actual benefit to the performance of the coating system.

Galvanised steel

Abrasive blast cleaning

After removal of excess zinc and surface defects the area to be coated shall be degreased to ISO 12944-4, Part6.1.4 Alkaline Cleaning. The galvanised surface shall be dry abrasive brush off blast cleaned with the nozzle angle at 45-60° from perpendicular at reduced nozzle pressure to create a sharp and angular surface profile using approved non-metallic abrasive media. As a guide, a surface profile 25-55 μm, grade Fine G; Ry5 (ISO 8503-2) should be achieved.

Care must be exercised when sweep blasting. The zinc coating thickness should be reduced as little as possible, preferably not more than 10 μm.

Smaller areas can be lightly treated with abrasive paper.

Finished surfaces shall be dull, profiled and show no areas of shiny metal.

After removal of excess zinc and surface defects the area to be coated shall be degreased with an alkaline detergent, washed by Low-Pressure Water Cleaning (LPWC) to a grade corresponding to the description of Wa 1 (ISO 8501-4) or higher standard and the surface abraded using mechanical or hand sanding methods using nonmetallic abrasives or bonded fibre abrasive pads to remove all polish and to impart a scratch pattern to the surface. Do not use high speed rotational sanders.

Hand and Power Tool Cleaning

After removal of excess zinc and surface defects the area to be coated shall be degreased with an alkaline detergent, washed by Low-Pressure Water Cleaning (LPWC) to a grade corresponding to the description of Wa 1 (ISO 8501-4) or higher standard and the surface abraded using mechanical or hand sanding methods using nonmetallic abrasives or bonded fibre abrasive pads to remove all polish and to impart a scratch pattern to the surface. Do not use high speed rotational sanders.

Water jetting

Inspect the surface for process residues, hydrocarbon contamination and corrosion by-products. If present, remove with an alkaline detergent. Agitate the surface to activate the detergent and before it dries, wash the treated area by Low-Pressure Water Cleaning (LPWC) to a grade corresponding to the description of Wa 1 (ISO8501-4) or higher standard using fresh water.

Aluminium

Abrasive blast cleaning

The surface to be coated shall be dry abrasive blast cleaned as required for the specified surface profile using approved non-metallic abrasive media which is suitable to achieve a sharp and angular surface profile. As a guide, a surface profile corresponding to 25-55 μm, grade Fine G; Ry5 (ISO8503-2) should be achieved.

Examples of recommended abrasives are:

• Ferrite free almandite garnet grade 30/60 and 80 grade (US Mesh size)

• Aluminium oxide grade G24.

Stainless steel

Abrasive blast cleaning

The surface to be coated shall be dry abrasive blast cleaned as required for the specified surface profile using non-metallic abrasive media which is suitable to achieve a sharp and angular surface profile. As a guide, a surface profile corresponding to 25-55 μm, grade Fine G; Ry5 (ISO 8503-2) should be achieved. Examples of recommended abrasives are:

• Ferrite free almandite garnet grade 30/60 and 80 grade (US Mesh size)

• Aluminium oxide grade G24.

Chlorinated or chlorine containing solvents or detergents must not be used on stainless steel.