painting system

1. Description of painting system
PROJ ECT: GHALEMDI KHOLA HYDROPOWER PROJ ECT (5 MW)

2. 1. Definition and Abbreviation .................................................................................................................. 2
2. Purpose............................................................................................................................. .................... 2
3. Scope of Works ............................................................................................................................. ........ 2
4. References ............................................................................................................................................ 3
5. Contract Requirement of Painting Specification .................................................................................. 3
6. Method of Application .......................................................................................................................... 4
6.1. PaintSystemfor PenstockPipes……………………………………………….. .............................................. 4
6.1.1. Surface Preparation .............................................................................................................. 4
6.1.2. Paints use & Tolerance……..................................................................................................... 5
7. Applicationof paint……………………………………….................................................................................. 5
8. Annexes ……………………………… .............................................................................................................. 5

3. 1. Definition and Abbreviation
Employer : Ghalemdi Hydro Ltd.
Consultant : Nirvana Tech.Pvt.Ltd.
Contractor : CE Hydro Mechanical Work Pvt. Ltd.
Project : Ghalemdi Khola Hydropower Project (5 MW)
HSS : Hydraulic Steel Structure
LPPP : Low Pressure Penstock Pipe
HPPP : High Pressure Penstock Pipe
SSPC : The Society for Protective Coatings
SIS : Swedish Standard Institute
IS : Indian Standard
2. Purpose
Ghalemdi Khola Hydropower Project is a Run-off type hydro project with rated electrical capacity of 5
MW. The project are located at Narchyang VD of myagdi district of Nepal respectively. The contract for
Hydro-mechanical works: LOT 2 Hydraulic Steel Structure (HSS) works of this project was awarded to
CE Hydro Mechanical Work Pvt. Ltd.
This document is prepared in order to give technical specifications of the painting systems that are
proposed to be applied for HSS works of the project, as per the contract requirement and is meant to take
approval of the painting systems and specifications from the consultant. This document contains the
description of the Painting Systems and Specifications along with the annex of supporting documents like
product data sheets of paint manufacturers, references etc. The paints and painting systems described in
this document is proposed by the contractor to be applied in the HSS works of the project such as
Penstock Pipes . The information contained in this document shall be read in conjunction with the
references as enlisted in the references part of this document.
3. Scope ofWorks
The scope of works of the Contractor shall be as per the Contract Documents. But in particular to the
work related with this document, the Contractor shall perform the following:
:Priming and application of the finishing coating on all equipment to be painted.
o Surface Preparation
2

4. ƒ Cleaning
ƒ Rust Removal
o Priming
o Finishing Coating
4. References
1. LOT 2: HSS, Section I: General Specification
2. LOT 2: HSS, Section II: Technical Specification
5. ContractRequirement of Painting Specification
The technical requirement of the painting systems have been specified in the various contract clauses as
follow:
1. Chapter 34, Protection, Cleaning and Painting, LOT 2: HSS, Section I: General Specification
2. Sub Clause 2.12 Painting Inspection, LOT 2: HSS, Section II: Technical Specification
The contractor shall follow the prescribed specifications in accordance with the contract and as
recommended by the latest paint code sand standards.
Specifically, for the technical requirements of surface preparation, paint specification and nominal dry
film thickness of each coat, the, LOT 2: HSS, Section I: General Specification has specified the detail
requirement which is based on the type of surfaces in terms of the medium that the surface is in contact.
This is presented below in tabular form for explanatory purpose of this document.
Surface : Wetted/Buried/Expose Surface
All steel surfaces in contact with water, e.g. steel linings, penstock, turbines, various piping (dia. 600 mm
and bigger), etc. shall be protected as follows:
Surface Preparation B St 3 (SIS)
Prime Coat 1 x 2-Component epoxy zinc rich primer
Dry film thickness 1 x 50 microns: 50
microns
Finish Coat 3 x 2-Component coal-tar expoxy
Dry film thickness 3 x 100 microns: 300
microns
Total dry film thickness 350 microns
3

5. 6. Method of Application
6.1. Paint System for PenstockPipes
6.1.1. Surface Preparation
After the pipes have been fabricated it is essential that the surface is properly prepared before applying
primers and final coats. Such preparation shall include thorough cleaning smoothing, drying and similar
operation that may be required to ensure that the primer and or paint is applied on suitable surfaces. The
procedure for surface preparation will be as follows:
• Weld spatters or any other surface irregularities will be removed by any suitable means before
cleaning.
• All oil, grease and dirt will be removed from the surface by the use of suitable cleaning material.
• Following the cleaning, the surfaces to be painted have to be free from rust and mill scales. The
surface preparation of these components is B St 3 (SIS) for internal and external surfaces, The
rust formed during the storage period will be removed by scrapping, brushing or grinding to the
grade St 3 SSPC.
• A good quality primer designed for application on rusted steel surface will be applied on the
bare steel surface before application of Finishing Layers. The method of application of such
paints will be followed as per the manufacturers’ recommendations and to meet the desired type
of paints.
• Primers will be applied as soon as the surface preparation is complete and prior to the
development of surface rusting. In case there is considerable time gap, the surface will be
cleaned prior to painting.

6. 6.1.2 Paints Use &Tolerances
The painting shall be performed one primer coat and three coats of coal-tar expoxy resin paints. in all
surface (Wetted, Buried& Expose ) & chembond, Berger & Shalimar brands paints are preferred depends
on the contractor choice & market availability of products.
Reference on the LOT-2 HYDRAULIC STEEL STRUCTURES General Specification consultant
provided total dry film thickness is 350 micron .than contractor gives the tolerances limits are +40% &
-20% which are acceptable.
7. Application of Paint
The contents of the paints will be mixed thoroughly as directed by the paint manufacturer before and
during use. Methods of paint application are:
a) Brush/Roller
b) Conventional spray
Painting at shop can be done in any of the two methods so that the paint can be made to suit the
convenient direction. the general method adopted is only by brush/roller. For the penstock pipe, any of the
two methods can be employed to paint at the field.
8. Annexes
Annex (i): Photograph of rust grade B as per SSPC
Annex (ii): Photograph of surface preparation grade B St 2 as per SSPC
Annex (iii): Photograph of surface preparation grade B St 3 as per SSPC

7. Attachment (i): Photograph of rust grade B as per SSPC

8. Attachment(iii):Photographof surface preparationgrade BSt2 as per SSPC

9. Attachment (iv): Photograph of surface preparation grade B St 3 as per SSPC

14. PREPARATION GRADE: B SA 2

15. PREPARATION GRADE: B St 3