ISO 15741 Paints and Varnishes - Friction-reducing Coatings for Internal Sections of Steel Pipelines, Onshore and Offshore, for Non-Corrosive Gases

The standard "ISO 15741 Paints and varnishes - Friction-reducing coatings for internal parts of onshore and offshore steel pipelines for non-corrosive gases" published by the International Organization for Standardization (ISO) describes the test requirements and methods for liquid epoxy paints and internal coatings of such paints on steel pipes and fittings for the transport of non-corrosive gases. This standard also deals with the application of the paint.

Other paints or paint systems are not excluded provided they comply with the requirements given in this standard. The coating normally consists of a single coat applied in the shop onto blasted steel by airless spray or other suitable spray techniques. The applied and cured paint film should be smooth to provide the desired reduction in friction. Brush application is only used for minor repair work.

For the purposes of this standard, the following definitions apply in addition to the terms and definitions given in ISO 4618:

The coater is the company responsible for applying the coating material in accordance with the principles of this standard.
The coating material manufacturer is the supplier of the coating material.
Dry film thickness is the thickness of the coating that remains on the surface when the coating has hardened or cured.
Natural gas is a complex gas mixture of hydrocarbons, primarily methane, but also often contains much smaller amounts of ethane, propane, and higher hydrocarbons, and some non-flammable gases such as nitrogen and carbon dioxide.
Nominal dry film thickness is the dry film thickness specified for each coat or the entire paint system.
A pinhole is a film defect characterized by small pore-like defects in a coating that pass completely through the applied film and have the appearance of a pinhead when viewed with reflected light.
The purchaser is the organization or person who purchases coated pipes and fittings.

The coating material is typically a two-component epoxy paint. The paint film must be released after curing and must not contain any substances that have been proven to be detrimental to the operation of the pipeline and the quality of the gas.

Unless otherwise agreed, the coating material must be qualified in accordance with this standard and must not be modified after qualification.

The manufacturer of the coating material shall provide infrared spectrograms of the base component and the curing agent component upon request. In addition, the manufacturer shall provide a product data sheet, a health and safety data sheet and a certificate stating the test results obtained in accordance with this standard and any other test conditions.

The manufacturer also provides a batch test certificate with each batch of coating material, stating the information given in this standard.

Unless otherwise agreed, the applied coating shall provide corrosion protection during storage and transport for a period of at least one year without significant deterioration of the coating. Typical operating temperature ranges for this type of coating are between minus 20 degrees and plus 110 degrees. When subsequent external coatings are required, care should be taken to ensure that the high temperatures that may occur do not damage the internal coating.

Laboratory test methods required for qualification of the coating material include:

Non-volatile matter (by mass): When determined according to ISO 3251, the non-volatile matter (by mass) of the coating material shall comply with the value stated in the qualification certificate by the coating material manufacturer.
Non-volatile matter (by volume): When determined according to ISO 3233-1, the non-volatile matter (by volume) of the coating material must comply with the value stated in the product data sheet by the coating material manufacturer.
Viscosity: When determined by the method specified by the manufacturer, the viscosity of the ready-mixed coating material must comply with the value specified in the qualification certificate by the coating material manufacturer.
Density: When determined according to the ISO 2811 series of standards, the density of the coating material must comply with the value specified in the product data sheet by the coating material manufacturer.
Ash (ignition residue): When determined according to the method described in the annex to the standard, the ash (ignition residue) of the coating material shall comply with the value stated in the qualification certificate by the coating material manufacturer (Annex A).
Pot life is considered as the time required for the ready-mixed coating material to reach a state beyond which it can no longer be applied satisfactorily. Pot life should be stated on the product data sheet.
Infrared spectrograms: Infrared spectrograms of the base component and the curing agent component are available on request.
The appearance and continuity of the coating should be visually inspected without any magnification.

Specific requirements for qualification of the hardened paint film are:

Preparation of test panels: The tests specified in this standard are carried out on coatings applied to the required dry film thickness. Steel test panels are prepared as specified in the standard and glass panels as specified in Annex E. Paint is applied in accordance with the coating material manufacturer's instructions. Each test is carried out at least twice.
If specified, coated test panels are conditioned using one of the cycles given in the standard, depending on the substrate and individual test. Cycle B and Cycle C are optional and the choice of conditioning cycle depends on the time available to perform the test procedure.
Dry film thickness: Unless otherwise agreed, the dry film thickness of the coating applied to the glass or steel panel shall be between 60 µm and 100 µm, except for the neutral salt spray resistance test method described in this standard. Unless otherwise agreed, the dry film thickness shall be measured in accordance with ISO 19840.
Adhesion: When determined in accordance with ISO 2409, the cross-sectional classification of the coating applied to steel panels and conditioned using the B or C cycle shall be equal to or less than this standard.
When Buchholz hardness is determined in accordance with the ISO 2815 standard, the coating applied to glass or steel panels and conditioned using the B or C cycle must have a Buchholz hardness of 94 or more.
Resistance to neutral salt spray: Coating applied to steel panels with a dry film thickness of 60 µm to 75 µm, conditioned using the B or C cycle and X-cut to the substrate at least 20 mm from any edge, is tested for 9227 hours in accordance with ISO 480. After testing, the test panels are allowed to dry for at least 18 minutes at 25°C to 80°C and a relative humidity of not more than 30 percent.

Among the numerous testing, measurement, analysis and evaluation studies that our organization has carried out for businesses in various sectors, our organization also provides testing services defined in the standard “ISO 15741 Paints and varnishes - Friction reducing coatings for the interior of onshore and offshore steel pipelines for non-corrosive gases” with its trained and expert staff and advanced technological equipment.