Defects in Industrial Painting
Content
DEFECTS IN INDUSTRIAL PAINTING
1)
2)
3)
4)
5)
6)
7)
8)
GENERAL RUSTING
PIN POINT RUSTING
SPOT RUSTING
PEELING
BLISTERING
SAGGING
CRACKING
LOSS OF ADHESION
Inspection Procedure :
1) A survey of the structures is done for
Determining the general types of unique components like shell, roof, ladders
and piping for a storage tank, Helideck top side and the service exposure
environment for each.
Visually identify areas having a typical level of coating deterioration and rust
break through for each component.
Identify areas having a much greater visual level of deterioration than typical
and unique environmental conditions that may correspond to these areas like
weld joints, edges of roof support beams and secondary support channels.
Record the description of components and their general environment on an
inspection form and describe areas having greater deterioration as well as any
unique associated environments in the remarks column.
2) Based upon the data of what constituents the typical deterioration for each
component as a determined in the initial survey ,examine the condition of
coating on a representative sample of each component.
Rate the condition of the coatings using appropriate ASTM visual standard for
rust break through Test method ASTM D610,Blistering Test method ASTM D
714,Peeling (use test method ASTM D610 to report amount),chalking (Test
Method D4214) and cracking / checking test method D660) of the coating film.
3) Record the rating in the appropriate column of the report form for each
Component.Determine and record the type of peeling like inter coat deLamination,total loss of adhesion. Rate the condition in enough areas that each
component the coating evaluation is representative of the condition over the
entire structure.If additional areas of greater deterioration are detected during
this assessment make note of them in the remarks column.
4) When rusting beneath an intact coating film is suspected, remove the coating
And examine the condition of the underlying substrate. Remove the intact
coatings using paints strippers / removers or closely spaced parallel knife
Coats. For structural steel, determine the type of previous surface preparation
From the presence of mill scale or profile, identify evidence of corrosion from
the presence of pits, black anodic spots or corrosion scale. Record the results of
the examination on the report form.
5) Using one of the procedures described in the Test Method D1186 determine the
Coating thickness in enough areas of each component to ensure a representative
Measure. Record the adhesion reading and the type of procedure and equipment
Used. The measure of coating adhesion shall be done using one of the procedure
described in Test methods of ASTM D3359 or ASTM D 4541.
6) Frequency of Inspection for Painted Surface : Annually
7) Repair Methodology :
The repair/rework shall be initiated when defect or combination of defects
becomes 10% of the area inspected at any point of time.The sample for assessing defect
shall be around 100m2 on each selective level/location of each un-manned platform.The
total number of sample areas shall not be less than 10 on each platform.The repair shall
be carried out by localized surface preparation and painting as per the maintenance
painting specification given in the tender document.The repair shall be upto the cover
tapping of intact coating area.
1)
2)
3)
4)
5)
6)
7)
8)
GENERAL RUSTING
PIN POINT RUSTING
SPOT RUSTING
PEELING
BLISTERING
SAGGING
CRACKING
LOSS OF ADHESION
Inspection Procedure :
1) A survey of the structures is done for
Determining the general types of unique components like shell, roof, ladders
and piping for a storage tank, Helideck top side and the service exposure
environment for each.
Visually identify areas having a typical level of coating deterioration and rust
break through for each component.
Identify areas having a much greater visual level of deterioration than typical
and unique environmental conditions that may correspond to these areas like
weld joints, edges of roof support beams and secondary support channels.
Record the description of components and their general environment on an
inspection form and describe areas having greater deterioration as well as any
unique associated environments in the remarks column.
2) Based upon the data of what constituents the typical deterioration for each
component as a determined in the initial survey ,examine the condition of
coating on a representative sample of each component.
Rate the condition of the coatings using appropriate ASTM visual standard for
rust break through Test method ASTM D610,Blistering Test method ASTM D
714,Peeling (use test method ASTM D610 to report amount),chalking (Test
Method D4214) and cracking / checking test method D660) of the coating film.
3) Record the rating in the appropriate column of the report form for each
Component.Determine and record the type of peeling like inter coat deLamination,total loss of adhesion. Rate the condition in enough areas that each
component the coating evaluation is representative of the condition over the
entire structure.If additional areas of greater deterioration are detected during
this assessment make note of them in the remarks column.
4) When rusting beneath an intact coating film is suspected, remove the coating
And examine the condition of the underlying substrate. Remove the intact
coatings using paints strippers / removers or closely spaced parallel knife
Coats. For structural steel, determine the type of previous surface preparation
From the presence of mill scale or profile, identify evidence of corrosion from
the presence of pits, black anodic spots or corrosion scale. Record the results of
the examination on the report form.
5) Using one of the procedures described in the Test Method D1186 determine the
Coating thickness in enough areas of each component to ensure a representative
Measure. Record the adhesion reading and the type of procedure and equipment
Used. The measure of coating adhesion shall be done using one of the procedure
described in Test methods of ASTM D3359 or ASTM D 4541.
6) Frequency of Inspection for Painted Surface : Annually
7) Repair Methodology :
The repair/rework shall be initiated when defect or combination of defects
becomes 10% of the area inspected at any point of time.The sample for assessing defect
shall be around 100m2 on each selective level/location of each un-manned platform.The
total number of sample areas shall not be less than 10 on each platform.The repair shall
be carried out by localized surface preparation and painting as per the maintenance
painting specification given in the tender document.The repair shall be upto the cover
tapping of intact coating area.
