Title: /
Clarify use of the words “Coating”, “Liner”, and “Lining” in the 11th Edition
Date: / Sept 11, 2007Contact: / Name: D.J. “Jerry” Boldra
Company : PetroChem Inspection
Phone : 713-880-0544
E-mail :
Purpose: / Clarify use of the words “coating”, “liner”, and “lining” throughout API 650, 11th edition
Source: / Discussion in Fabrication meeting at Fall Refinery meeting - 2006
Revision: / 0. Origination – Fall 2006. Agenda item requested by Jerry
Boldra
1. Moved to SCLB with changes noted in Sub-group
Fabrication – Fall 2007.
2.
Impact: / The cost impact of this item is neutral. The business impact will result in clarity and more precise communication.
Background: / Agenda Item was taken out as a result of inaccurate use of the words “coating”, “liner” and “lining”. This results in confusion and inefficiency in written and oral communication.
Legend: / Red print = existing “coat”, “coated”, and “coating” words in 11th
edition. A word search was performed and ALL
references in the 11th edition to these three words
ARE listed below.
Strike thru = proposed deletions
Green print = proposed additions
Italics = explanatory notes (delete these before publishing)
Light gray = no change to existing text.
Proposal:
(Page 3-1)
3.2 coating: A protective material applied to external and internal surfaces of a tank, or to inaccessible surfaces (the underside of the tank bottom) In this Standard, the term includes materials frequently described as painting and lining materials.
3.2 coating: Generic term for various protective materials applied to external, internal and inaccessible surfaces (the underside of the tank bottom) of an aboveground storage tank. In this Standard, the term may be used as a noun or verb*. It includes liquid paint, protective metal processes (e.g. galvanizing, cadmium plating, etc.), pipe** coatings, and plastic or polyolefin materials. For specific language about protective materials in internal service, either in immersion or vapor space, see the definition of “lining”.
* (for use of “coating” as a verb, see Paragraphs 5.4.5; Figure 5-5; 7.3.6.1; C.3.8.1; C.3.8.3)
** (for “pipe coating”, see Figure O-3, page O-5)
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X.X liner: Fiberglass, metal, plastic, polyolefin, or rubber sheeting used as a barrier, but is not adhered to the protected surface. Typically used (1) inside a tank to protect steel, e.g. lead sheeting in sulfuric acid service, (2) under a tank for leak detection, or (3) in a dike yard as secondary containment.
(for use of the word “liner” in API 650, see Figures I-1; I-2; I-3; I-4; I-6; I-8; and I-9)
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X.X lining: A paint material, that is applied, dries, cures and develops strong adhesion to the substrate. This protective material is designed for immersion service or vapor space service. Note that Table 6-1 in API 653 requires a reinforced lining, and API 652 requires a reinforced fiberglass lining.
(for use of the word “lining” , see API 653 Table 6-1, and the title of API 652. Other
industry references can be furnished upon request.)
(Note to API staff: After inserting the two new definitions, please re-number the
subsequent defined words in Section 3-- DEFINITIONS)
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(No change)
• 5.4.5 If specified on the Data Sheet, Line 12, a foundation drip ring shall be provided to prevent ingress of water between the tank bottom and foundation. Unless the Purchaser specifies otherwise, the ring shall meet the following requirements (see Figure 5-5):
1. Material shall be carbon steel, 3 mm (1/8-in.) minimum thickness.
2. All radial joints between sections of the drip rings, as well as between
the drip ring and the annular plate or bottom, shall be continuously seal-
welded.
3. The drip ring shall extend at least 75 mm (3 in.) beyond the outer
periphery of the foundation ringwall and then turn down (up to 90°) at its
outer diameter.
4. The top and bottom of the drip ring, and the top of the tank bottom edge
protection beyond the shell, and a portion of the tank shell shall be coated
if specified by the Purchaser.
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(No change)
Figure 5-5—Drip Ring (Suggested Detail) (Page 5-9)
Coat if
specified
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(Page 5-60)
5.10.2.3 Roof plates of supported cone roofs shall not be attached to the supporting members unless otherwise approved by the Purchaser.
Continuously attaching the roof to cone supporting members may be beneficial when interior coating lining systems are required, however, the tank roof cannot be considered frangible (see 5.10.2.6).
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(No change)
6.1.1.3 Materials used to aid in the fabrication of tanks shall not have a detrimental effect on the structural integrity of the tank. Lubricants, crayons, adhesives, and anti-weld spatter compounds shall not contain materials that will be detrimental to the tank, e.g., sulfur and chloride compounds for stainless steel materials. Attachments that will be welded to the pressure boundary shall not have a zinc or cadmium coating in the weld area within 12 mm (0.5 in.) of the weld.
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(No change)
7.1.3 Coating or foreign material shall not be used between surfaces in contact in the construction of the tank, except as permitted by 7.2.1.9.
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(No change)
• 7.1.4 Coating or other protection for structural work inside and outside of the tank shall be as specified in the contract and shall be applied by competent workers.
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(Page 7-1)
7.1.6 All temporary attachments welded to the interior of the tank, including the shell, roof, tank bottom, roof columns and other internal structures shall be removed and any noticeable projections of weld metal shall be ground smooth. In the event of inadvertent tearing of the plate when attachments are removed, the damaged area shall be repaired by welding and subsequent grinding of the surface to a smooth condition. This work must be completed before the application of internal coatings linings, the air raising of a fixed roof, the initial floating of a floating roof, and any other circumstance whereby projections may cause damage.
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(No change)
7.2.1.9 If protective coatings are to be used on surfaces to be welded, the coatings shall be included in welding-procedure qualification tests for the brand formulation and maximum thickness of coating to be applied.
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(No change)
7.3.6.1 This hydrostatic test of the tank shall be conducted before permanent external piping is connected to the tank. Attachments to the shell defined in 5.8.1.1, located at least 1 m (3 ft) above the water level, and roof appurtenances may be welded during the filling of the tank. After completion of the hydro-test, only non-structural small attachments may be welded to the tank in accordance with 7.2.1.11. Any welded joints above the test-water level shall be examined for leakage by one of the following methods:
1. coating all of the joints on the inside with a highly penetrating oil, such
as automobile spring oil, and carefully examining the outside of the
joints for leakage;
2. applying vacuum to either side of the joints or applying internal air
pressure as specified for the roof test in 7.3.7 and carefully examining
the joints for leakage; or
3. using any combination of the methods stipulated in Subitems 1 and 2.
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(No change)
9.2.1.4 Welding variables (including supplementary essential variables when impact tests are required by 9.2.2), as defined by QW-250 of Section IX of the ASME Code, shall be used to determine the welding procedure specifications and the procedure qualification records to be instituted. In addition, when impact tests of the heat-affected zone are required, the heat-treated condition of the base material shall be a supplementary essential variable. If a protective coating has been applied to weld edge preparations, the coating shall be included as an essential variable of the welding procedure specification, as required by 7.2.1.9.
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(Page C-2)
C.3.2.2 If a lining will be applied to the underside of the roof is to be coated, all coated joints that will have a lining shall be seal-welded.
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(No change)
C.3.8.1 Primary Roof Drains
• 1. Primary roof drains shall be sized and positioned to accommodate the rainfall rates specified on the Data Sheet, Line 33, while preventing the roof from accumulating a water level greater than design, without allowing the roof to tilt excessively or interfere with its operation. Roof drains shall be furnished attached to double-flanged, low-type nozzles on the tank shell with valves to be supplied by the Purchaser. A swing-type check valve shall be provided at the inlet of drains unless otherwise specified on the Data Sheet, Line 32. The drains shall be removable, if required by the Purchaser. Primary roof drains shall not be smaller than NPS 3 for roofs with a diameter less than or equal 36 m (120 ft) or smaller than NPS 4 for roofs with a diameter greater than 36 m (120 ft).
2. Primary roof drains shall be resistant to the tank’s contents, or suitably coated, and shall be free from floating, kinking, or catching on any internal appurtenance or obstruction during operation, and from being crushed by landing legs on the bottom.
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(No change)
C.3.8.3 Out-of-Service Supplementary Drains
•Threaded pipe couplings and plugs with a 600-mm (24-in.) extension “T-bar” handle shall be provided as supplementary drains when the roof is resting on its legs and when the primary drains are inoperative. The number of drains shall be based on the specified rainfall rate (see Line 33 of the Data Sheet) and tank size. Fittings shall be at least NPS 4. Plugs shall have threads coated with a non-stick coating or anti-seize paste such as tetrafluoroethylene. One supplementary drain shall be located adjacent to the ladder track.
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(No change)
G.11.2 FABRICATION
All roof parts shall be prefabricated for field assembly. Fabrication procedures shall be in accordance with Section 6 of the Aluminum Design Manual. All structural shapes used to make the roof shall be punched or drilled before any shop coating is applied.
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(No change)
G.11.4 SHIPPING AND HANDLING
Materials shall be handled, shipped, and stored in a manner that does not damage the surface of aluminum or the surface coating of steel.
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(No change)
H.4.4.4 Types of Primary Seals (Page H-5)
a. Liquid-mounted rim seal: Means a resilient foam-filled or liquid-filled primary rim seal mounted in a position resulting in the bottom of the seal being normally in contact with the stored liquid surface. This seal may be a flexible foam (such as polyurethane foam in accordance with ASTM D 3453) or liquid contained in a coated fabric envelope. Circumferential joints on liquid-mounted peripheral seals shall be liquid-tight and shall overlap at least 75 mm (3 in.). The material and thickness of the envelope
fabric shall be determined after the factors given in H.4.4.2 are considered.
b. Vapor-mounted rim seal: Means a peripheral seal positioned such that it does not normally contact the surface of the stored liquid. Vapor-mounted peripheral seals may include, but are not limited to, resilient-filled seals (similar in design to liquid-mounted rim seals per H.4.4.4a), and flexible-wiper seals. Flexible-wiper seal means a rim seal utilizing a blade or tip of a flexible material (such as extruded rubber or synthetic rubber) with or without a reinforcing cloth or mesh.
c. Mechanical shoe (metallic shoe): Means a peripheral seal that utilizes a light-gauge metallic band as the sliding contact with the shell and a fabric seal to close the annular space between the metallic band and the rim of the floating roof deck. The band is typically formed as a series of sheets (shoes) that are overlapped or joined together to form a ring and held against the shell by a series of mechanical devices.
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(No change)
H.4.4.4 Types of Primary Seals (Page H-5, second paragraph)
Galvanized shoes shall conform to ASTM A 924 and shall have a minimum nominal thickness of 1.5 mm (16 gauge) and a G90 coating. Stainless steel shoes shall conform to H.3.3, and shall have a minimum nominal thickness of 1.2 mm (18 gauge). For internal floating roofs the primary shoes shall extend at least 150 mm (6 in.) above and at least 100 mm (4 in.) into the liquid at the design flotation level. If necessary, bottom shell course accessories (e.g., side mixers) and other assemblies shall be modified or relocated to eliminate interference between lower portions of metallic seal assemblies.
(Page H-5)
• Unless specified otherwise by the Purchaser, the seal shoe and compression mechanism shall be installed before hydrostatic testing. It may be necessary to remove the seal shoe after the hydro-test to accommodate cleaning, application of interior coatings linings, or any situation where the installed shoe might interfere with the process. The fabric seal may be installed after the hydrostatic testing.
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(Page H-7)
• H.4.6.8 Special protective measures (corrosion allowance, material selection, coatings linings ) are to be evaluated for supports that interface with stratified product bottoms, which may include corrosive contaminant combinations not found in the normal product. The Purchaser shall specify if any protective measures are required.
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(Page H-7)
• H.4.6.9 For tanks with internal coatings linings, the Purchaser shall specify on Line 23 of the Data Sheet any special requirements for minimizing corrosion where the leg contacts the tank bottom, such as a flat plate or bull nose on the leg base, a thicker base plate, or other means.
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(Page I-1)
I.1.5 For additional information on the use of internal coatings linings to prevent internal bottom corrosion, see API RP 652. Similarly, see API RP 651 for guidelines and requirements relating to preventing corrosion from the soil side of the bottom plate.
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(No change)
Figure I-6
Flexible membrane
liner or applied coating
for leak tightness