How to Write Paint Specifications A.S.Khanna Corrosion Science & Engineering IIT Bombay
What do we mean by Paint Specification • Protecting a surface with a paint coating that takes care of the requirements of a user • Requirements – Chemical Resistance • Resistance to chlorides, acids, alkalies, solvents – Mechanical Properties • Impact, scratch, abrasion, bond strength – Weathering properties • Resistance to UV, rains, snow – Heat Resistance • Highest Temperature a paint can resist – Low Temperature resistance • Lowest temperature a paint can resist
Selection Criteria • Location – Environment • Mild, Urban, Coastal • Onshore • Offshore – Mud line – Silent water Zone – Splash Zone
Selection Criteria … contd • Surface Finishing Requirements – New Surface – Old Surface • Whether possibility of complete Cleaning • Partial cleaning • Application Technique – Brush – Roller – Air Spray – Airless Spray • Life of Coating – Long Life – Short Life • Cost
Type of paints • Conventional Solvent based Paints – Requires more time to dry – High DFT in several coats – Large recoating intervals – Chances of malpractices – tempering of resin ./ solvent composition • Modern paints – Solventless Paints – High DFT in single coat – Modified by Glassflake enhance life by several folds.
Ensuring Proper Raw Materials • Initial Checking of the composition of the paint- resin, hardener, thinner etc. – Volume solid – Viscosity – Density • Batch Testing of Each Batch
Performance tests – pre Qualifications • Chemical Resistance • Weathering • Mechanical Properties • Special Tests – if any
Qualified Personal • It is now very important to properly check the staff who are going to take the job: – Technical Qualification of applicators / Surface preparation – Qualified Supervisor – Qualified Inspectors • Their role must be specified and data collected must be properly arranged and checked.
Coating Conditions • Proper Humidity • Proper Temperature • Free from salt deposition • Free from contamination by salt aerosols etc.
Environment Surface Preparation Coating System No. of DFT in (μm) Category as per Required as per ISO 8501 Coats (ISO-12944-2) C 3 St 2 Medium durability Non-immersion Primer : MIO based alkyd 1 50 Medium Corrosion Top Coat : Modified Alkyd ( with urethane) 1 50 ( Temperature up to 120 o C) Long Durability Primer: Epoxy Mastic 1 50 Top Coat – 2 Pack Aliphatic PUR 1 100 Sa 2.5 Medium Durability 2 coats of Alkyd 2 150 Long Durability 1 50 Primer – Zn-rich 1 80 Top Coat -2 pack Aliphatic PUR C 4 Sa 2.5 Medium Durability Non-immersion Primer : Zn-rich epoxy 1 50 ( High Corrosion) Intermediate : Epoxy MIO 1 60 Top Coat : 2 pack Aliphatic PUR 1 50 Long Durability Primer: Inorganic Zn- Silicate 1 50 Intermediate : Epoxy MIO 2 150 Top Coat: 2 pack Aliphatic PUR 1 50 C 5 Sa2.5 Medium Durability Non-immersion Primer : Inorganic Zn- Silicate Intermediate: Epoxy MIO 1 50 Very High Corrosion Top Coat: 2 pack Aliphatic PUR 2 150 (2x75) ( Temperature up to 120 o C 1 50 Long Durability Primer : Inorganic Zn- Silicate 1 50 Intermediate : high Build Epoxy MIO 2 160 (2x80) Top Coat : 2 pack Aliphatic PUR 1 50 C 3 Sa2.5 Medium Durability Non-immersion Aluminum Coating 2 250 Medium Corrosion Long Duration ( Temperature up to 400 o C Primer: Inorganic Zn- Silicate 1 50 Top Coat : Silicon Based Coating 2 200 C 3 Sa 2.5 Medium Durability Non-immersion Primer - Silicon Based 1 50 Medium Corrosion Top Coat : Polysiloxane 2 250 ( Temperature up to 600 o C
Immersion Sa 2.5 Service Solvent Less Epoxies 1 500 Tanks for fuel, oil, crude, chemicals and process water Immersion Sa 2.5 Service Glassflake Epoxies 1 or 2 1000 or more Sewage lines, or water treatment Combination of Glassflake and Reinforced epoxies facilities Immersion Sa2.5 Polyester Glassflake 1 1000 Service HA 2 Water Repellent Epoxies 2 2x400 Splash Zone in Sea Water Underwater Immersion Sa 2.5 Glassflake Epoxy Service Or Novolac Epoxy 1 or 2 1500-2000 Water Jetties Sea Water Immersion Service Sa 2.5 Solvent less Epoxies 1 1000 Freshwater Treatment facilities, locks and gates External 2000 – 3000 Underground Sa 2.5 Oil & Gas 3 Structures 3 layer PE ( FBE Primer, Adhesive and 1 3000-5000 Gas Pipelines PE) 700-1000 Water Pipelines Water Pipelines Coal tar or Tar Epoxy, tar-urethane Liquid Epoxy, Elastomeric PU
Quality Control for Protective Coatings Projects A.S.Khanna Corrosion Science & Engineering IIT Bombay
Definition • QC gathers and documents the information that verifies that the work performed meets the minimum standards as required by specifications. • Quality assurance (QA) on the otherhand is to protect the against failures of quality control. It is process to verify that quality work was performed actually as claimed on the basis of QC. • The quality programme assures and controls the QA and QC as per industry standards. • The QC manager is a qualified person, appointed by top management to assure the quality of coating, which is evaluated on annual basis and recommendations of the corrective measures if any. • QA and QC inspector is the qualified person appointed by QC manager to perform individual inspections and verify the work being performed as per specifications, can introduce corrective measures or stop work, if not going as per specifications
Standards & Guidelines 1. SSPC-QP1 Standard Procedure for evaluating painting contractor( field application to complex industrial structures) 2. SSPC-QP3 Standard Procedure for evaluating Shop Painting Applicators. 3. SSPC-QP5 Standard Procedure for evaluating qualifications of coating and lining inspection companies .
Pre-Job Review 1. Contract & Specification review. 2. QC and inspector Requirements 3. Inspection Plan 4. Document control 5. Pre-job conference
QC and inspector Requirements 1. Formalised training & Certification of the inspector. 2. Experience in the type of structure to be inspected. 3. Availability of inspection equipments to the inspector. 4. Records of all inspection equipment used by inspector. 5. Standards & Procedures to show conformance with The specifications be available with the inspector. 6. Approved copies of materials supplier technical data sheets, application instructions and material safety.
Inspection Plan • Prior to the start of work, • Immediately following the surface preparation. • Immediately prior to the coating & lining application. • Following the application of each coat • Following the curing of coating or lining. • Final inspection and sign off
Daily Inspection Activities 1. Revision Log 2. Technical resource availability 3. Calibration verification 4. Daily work log 5. Daily inspection report 6. Corrective Actions 7. Photographic Records 8. Management review
Technical resource availability • SSPC Painting Manual Vol. 2, systems & specifications • SSPC PA2, Measurement of DFT • SSPC visual standards • ASTM protective coating inspection standards for field and shop applications. • Updated material supplier technical data sheets. • Standard procedures SSPC, NACE, ASTM, API, ISO
Calibration verification • Equipment type & serial number • Required frequency & calibration method. • Record of calibration data. • Signature and date of person performing calibration verifications.
Daily inspection report • Weather and site condition. • Pre-surface condition & cleanliness • Surface Preparation monitoring. • Post surface preparation cleanliness and profile. • Coating material preparation & application • Physical film properties, DFT measurement • Verification of corrective actions prior to final approval. • Record of equipments used for measurement
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