COMPLETE REVISION
September 2014
Process Industry Practices
Vessels
PIP VESV1003
Special Fabrication Requirements for Welded
Vessels and Tanks to Be Lined
PURPOSE AND USE OF PROCESS INDUSTRY PRACTICES
In an effort to minimize the cost of process industry facilities, this Practice has
been prepared from the technical requirements in the existing standards of major
industrial users, contractors, or standards organizations. By harmonizing these
technical requirements into a single set of Practices, administrative, application, and
engineering costs to both the purchaser and the manufacturer should be reduced. While
this Practice is expected to incorporate the majority of requirements of most users,
individual applications may involve requirements that will be appended to and take
precedence over this Practice. Determinations concerning fitness for purpose and
particular matters or application of the Practice to particular project or engineering
situations should not be made solely on information contained in these materials. The
use of trade names from time to time should not be viewed as an expression of
preference but rather recognized as normal usage in the trade. Other brands having the
same specifications are equally correct and may be substituted for those named. All
Practices or guidelines are intended to be consistent with applicable laws and
regulations including OSHA requirements. To the extent these Practices or guidelines
should conflict with OSHA or other applicable laws or regulations, such laws or
regulations must be followed. Consult an appropriate professional before applying or
acting on any material contained in or suggested by the Practice.
This Practice is subject to revision at any time.
© Process Industry Practices (PIP), Construction Industry Institute, The University of
Texas at Austin, 3925 West Braker Lane (R4500), Austin, Texas 78759. PIP Member
Companies and Subscribers may copy this Practice for their internal use. Changes or
modifications of any kind are not permitted within any PIP Practice without the express
written authorization of PIP. Authorized Users may attach addenda or overlays to clearly
indicate modifications or exceptions to specific sections of PIP Practices. Authorized
Users may provide their clients, suppliers and contractors with copies of the Practice
solely for Authorized Users’ purposes. These purposes include but are not limited to the
procurement process (e.g., as attachments to requests for quotation/ purchase orders or
requests for proposals/contracts) and preparation and issue of design engineering
deliverables for use on a specific project by Authorized User’s client. PIP’s copyright
notices must be clearly indicated and unequivocally incorporated in documents where an
Authorized User desires to provide any third party with copies of the Practice.
PUBLISHING HISTORY
April 2004 Issued
September 2008 Complete Revision
September 2014 Complete Revision
Not printed with State funds
COMPLETE REVISION
September 2014
Process Industry Practices
Vessels
PIP VESV1003
Special Fabrication Requirements for Welded
Vessels and Tanks to Be Lined
Table of Contents
1. Introduction......................................................................................................... 2
1.1 Purpose .................................................................................................................................. 2
1.2 Scope ..................................................................................................................................... 2
2. References .......................................................................................................... 2
2.1 Process Industry Practices ..................................................................................................... 2
2.2 Industry Codes and Standards ............................................................................................... 2
3. Requirements ...................................................................................................... 2
3.1 Welded Joints to Be Lined ...................................................................................................... 2
3.2 Welds ..................................................................................................................................... 3
3.3 Surface Contours ................................................................................................................... 3
3.4 Surface Finish......................................................................................................................... 3
3.5 Attachments............................................................................................................................ 4
3.6 Connections............................................................................................................................ 4
3.7 Tests and Inspections ............................................................................................................. 5
3.8 Weld Quality Samples ............................................................................................................ 5
3.9 Requirements for Vertical Tank Foundations .......................................................................... 6
Table 1 Special Requirements for Lining Systems ......................................................................... 7
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PIP VESV1003 COMPLETE REVISION
Special Fabrication Requirements for Welded Vessels and Tanks to Be Lined September 2014
1. Introduction
1.1 Purpose
This Practice provides fabrication requirements for equipment to be internally lined,
supplementing PIP VECV1001, PIP VESV1002, PIP VESSM001 and PIP VESLP001.
1.2 Scope
This Practice describes fabrication requirements for welded vessels, tanks, bins and silos
that are to be lined with nonmetallic linings including liquid-applied and sheet linings.
Provisions of this Practice are intended to apply only to surfaces to be lined.
2. References
Applicable parts of the following Practices, industry codes and standards, and references shall be
considered an integral part of this Practice. The edition in effect on the date of contract award
shall be used, except as otherwise noted. Short titles are used herein where appropriate.
2.1 Process Industry Practices (PIP)
– PIP VECV1001 - Design Criteria and Purchasing Requirements for Vessels
– PIP VEDV1003 - Documentation Requirements for Vessels, ASME Code Section VIII,
Divisions 1 and 2
– PIP VEFV1100 - Vessel/S&T Heat Exchanger Standard Details
– PIP VESSM001 - Specification for Small Pressure Vessels and Heat Exchangers with
Limited Design Conditions
– PIP VESLP001 - Low-Pressure, Welded Vessel Specification
– PIP VESV1002 - Design and Fabrication Specification for Vessels, ASME Code
Section VIII, Divisions 1 and 2
2.2 Industry Codes and Standards
ASME
– ASME Section VIII, Div. 1 - Rules for the Construction of Pressure Vessels
NACE International
– NACE Standard Practice SP0178 - Design, Fabrication and Surface Finish
Practices for Tanks and Vessels to Be Lined for Immersion Service
3. Requirements
3.1 Welded Joints to Be Lined
3.1.1 For in-plane joints, buttweld joints shall be used.
3.1.2 Continuous lap welds may be used for liquid applied linings in accordance with
Table 1, but are not preferred because of the difficulty in obtaining acceptable
radii for the welds.
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PIP VESV1003 COMPLETE REVISION
Special Fabrication Requirements for Welded Vessels and Tanks to Be Lined September 2014
3.1.3 Misalignment of plate edges shall not be greater than the limits permitted by the
applicable code or standard, but in any case shall not be greater than the lesser of
1/8 inch (3 mm) or 25 percent of the plate thickness.
3.1.4 Mismatched edges shall be blended into the adjacent surfaces by grinding.
Minimum required wall thickness shall be maintained.
3.1.5 Grinding shall be held to the minimum necessary to provide a minimum radius of
1/4 inch (6 mm) for a smooth surface for the lining.
3.1.6 The use of caulking compounds and putties shall not be permitted.
3.2 Welds
3.2.1 Welds shall be prepared in accordance with NACE Weld Preparation
Designation C for liquid-applied linings and Weld Preparation Designation A for
rubber and sheet linings.
3.2.2 See NACE Standard Practice SP0178, Appendix C for details of NACE Weld
Preparation Designations.
3.3 Surface Contours
3.3.1 Particular care shall be given to corners and edges over which the lining is to be
applied. All outside corners and edges shall be ground to a radius of 1/4 inch
(6 mm) or greater.
3.3.2 See Figure 1 for typical details for surface contours. See NACE Standard
Practice SP0178, Appendix A for additional details.
Fillet welds that are to be ground shall be
oversized, so that grinding a radius does not
reduce throat dimensions below code
requirements
Fillet weld, ¼” (6 mm)
minimum radius ¼” (6 mm) minimum radius
Figure 1. Surface Contours
3.4 Surface Finish
Weld surface finish shall be in accordance with NACE Standard Practice SP0178,
Section 5.
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PIP VESV1003 COMPLETE REVISION
Special Fabrication Requirements for Welded Vessels and Tanks to Be Lined September 2014
3.5 Attachments
3.5.1 Interior Structural Members
3.5.1.1 Partitions, braces, supports, or other attachments on the lined side of the
vessel shall be fitted flat against the vessel surface and continuously
welded around the entire perimeter.
3.5.1.2 See Figure 2 for typical details for internal attachments.
3.5.1.3 Pockets or crevices that cannot drain or be abrasive-blast cleaned shall
not be permitted.
3.5.1.4 Internal attachment configurations shall be in accordance with NACE
Standard Practice SP0178, Section 3, Paragraph 3.4.
3.5.1.5 Avoid the use of bolt holes that must be lined. However, if lined bolt
holes are required, bolt holes shall be drilled oversized as required for
the lining. All edges shall be rounded to 1/4-inch (6-mm) radius by
grinding.
¼” (6 mm)
minimum radius
¼” (6 mm)
Continuous welds, free from pores, minimum radius
ground smooth to ¼” (6 mm)
minimum radius
Figure 2. Internal Attachments
3.5.2 External Attachments
Lifting lugs shall be designed and located so that lining cannot be damaged
during lifts.
3.6 Connections
3.6.1 All nozzles and outlets shall be flanged or pad type.
3.6.2 Nozzles and manways shall be flush on the lining side with all corners rounded
to a radius of ¼ inch (6 mm).
3.6.3 See Figure 3 for typical details for nozzles and outlets.
3.6.4 Minimum nozzle size for lining shall be NPS 2 (DN 50) nominal size. Manways
shall be 24-inch (DN 600) nominal size.
3.6.5 For connections less than NPS 2 (DN 50), the use of a reducing flange should be
considered.
3.6.6 Flat face flanges are preferred, to allow lining of the flange face (see Figure 3).
For rubber or sheet lining, if flange faces are to be lined, flat face flanges shall
be used.
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PIP VESV1003 COMPLETE REVISION
Special Fabrication Requirements for Welded Vessels and Tanks to Be Lined September 2014
3.6.7 If raised face flanges are required by design, the lining shall extend only to the
outside of the raised face.
3.6.8 Maximum nozzle lengths are shown in Table 1.
3.6.9 To facilitate ventilation and heat curing, vertical tanks shall have a minimum of
one 12-inch (DN 300) diameter nozzle in the top head or roof, and horizontal
tanks shall be designed with one 6-inch (DN 150) diameter nozzle at each end. If
Table 1 requires two manways, the manways shall be located approximately 180
degrees apart.
All inside welds finished round &
smooth, ¼” (6 mm) minimum
¼” (6 mm) radius
minimum radius
Figure 3. Outlets
3.7 Tests and Inspections
3.7.1 Before the application of any lining, all equipment shall be inspected to verify
conformance to the provisions of this Practice.
3.7.2 After the vessel has been prepared for the lining, acceptability of surface
preparations shall be evaluated by the purchaser’s representative, using the
approved weld samples specified in Section 3.8.
3.7.3 The lining applicator shall inspect the vessel and certify that it is suitable for
lining.
3.7.4 All vessels, tanks, or other equipment shall be hydrotested after the final
grinding of all welds and prior to the final surface preparation of the vessel
before the application of a lining.
3.8 Weld Quality Samples
3.8.1 Representative weld samples, 6 inches (150 mm) long, with grinding if required,
shall be submitted representing each of the following welds:
a. Tank bottom welds. These can be either butt welds or fillet welds depending
upon the type applied.
b. Vertical shell welds
c. Horizontal shell welds
d. Roof welds
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PIP VESV1003 COMPLETE REVISION
Special Fabrication Requirements for Welded Vessels and Tanks to Be Lined September 2014
3.8.2 The samples shall represent the different types of welds present in the vessel,
tank, or equipment and shall be in accordance with the surface preparation
requirements of Sections 3.1 through 3.4 and Table 1.
3.8.3 The samples shall be submitted with drawings, for approval both by the
purchaser and the lining applicator, and used as standards to determine
acceptance in accordance with Section 3.7.1.
3.8.4 If the samples submitted are not approved, the purchaser and/or lining applicator
shall furnish a detailed written explanation of the reason for rejection. Additional
samples shall be submitted for approval.
3.9 Requirements for Vertical Tank Foundations
3.9.1 Except as specified in Section 3.9.2, the bottom of all field-erected, flat-bottom
tanks shall be fully supported before application of a lining to prevent deflection
that could damage the integrity of the lining when the tank is filled.
3.9.2 Section 3.9.1 shall not apply to tanks to be lined with an elastomeric lining.
However, the bottom of these tanks shall be sloped to permit removal of all
steam condensate, resulting from steam curing.
Comment: If this condensate is not removed, the result can be incomplete
curing of the elastomer.
3.9.3 For heat-cured plastic linings applied in the field, the tank foundation shall
possess adequate insulating properties, (e.g. a structural lightweight aggregate
concrete).
Comment: Insulation is necessary to reduce the heat loss through the foundation
to ensure that the lining on the tank bottom reaches the required cure
temperature.
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PIP VESV1003 COMPLETE REVISION
Special Fabrication Requirements for Welded Vessels and Tanks to Be Lined September 2014
Table 1. Special Requirements for Lining Systems
Liquid Applied Linings
Sheet linings
Specification Glass– (adhesively
Thin Film
Rubber linings reinforced bonded) (Note 3)
linings
resin linings
Butt welds permitted Yes Yes Yes Yes
Lap welds permitted No Yes Yes No
Welds shall be flush Yes No No (Note 1) Yes
Welds shall be smooth Yes Yes (Note 2) Yes (Note 2) Yes
Weld spatter permitted No No No No
Maximum nozzle length
NPS 2 (DN-50) 6 in. (150 mm) Not Permitted Not Permitted Unlimited (Note 4)
NPS 3 (DN-80) 12 in. (300 mm) 4 in. (100 mm) 4 in. (100 mm) Unlimited (Note 4)
NPS 4 (DN-100) 24 in. (600 mm) 8 in. (200 mm) 8 in. (200 mm) Unlimited (Note 4)
Minimum number of 1 2 (heat cured) or 1 (epoxy) or 2
manways in tanks for 1 (chemically 2 (polyester)
application of lining cured)
Grout tank bottom to No Yes Yes Yes
minimize deflection or “oil-
canning” (see Section 3.9 for
flat bottom tanks)
Use insulating or structural No Yes (heat cured) No No
lightweight aggregate No (chemically
concrete for tank foundation cured)
(see Section 3.9.3)
Notes: 1. Maximum height of any weld bead shall be in accordance with ASME Code or 1/8 inch (3 mm), whichever is
less. Welds shall blend into the adjacent surface so that the glass fabric saturated with resin is able to follow
this contour and not leave a gap or an air space.
2. Weld ripples are acceptable if they are shallow enough so that crevices and depressions can be cleaned by
sandblasting to remove slag and oxides.
3. Typically, 60 mils thick or greater.
4. Use insert linings. If loose linings are used for nozzles, venting is required.
Process Industry Practices Page 7 of 7
