SH/T 3537-2009 English PDF (SHT3537-2009)
SH/T 3537-2009 English PDF (SHT3537-2009)
SH/T 3537-2009: Technical specification for construction of vertical cylindrical low temperature storage tank
PETROCHEMICAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Filing No.: J1019-2010
Replacing SH 3537-2002
Technical specification for construction of vertical
cylindrical low temperature storage tank
ISSUED ON: DECEMBER 04, 2009
IMPLEMENTED ON: JUNE 01, 2010
Issued by: Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword ... 4
1 Scope ... 6
2 Normative references ... 6
3 General provisions ... 7
4 Construction preparation ... 8
4.1 Technical preparation ... 8
4.2 Site preparation ... 9
5 Materials ... 9
6 Construction process ... 10
7 Prefabrication ... 11
7.1 General requirements ... 11
7.2 Base plate prefabrication ... 12
7.3 Wall plate prefabrication ... 15
7.4 Vault prefabrication ... 16
7.5 Prefabrication of inner suspension roof ... 18
7.6 Prefabrication of other components ... 19
7.7 Exit-factory of prefabricated parts ... 19
8 Review of foundation and reinforced concrete outer tank ... 20
8.1 Foundation review ... 20
8.2 Re-examination of reinforced concrete outer tank ... 21
9 Tank bottom assembly ... 22
9.1 General requirements ... 22
9.2 Assembly of tank bottom plate with overlap joints ... 23
9.3 Assembly of butt joint tank bottom plate ... 24
9.4 Assembly of inner tank bottom of double-layer low-temperature storage tank ... 25 10 Tank wall assembly ... 26
10.1 General requirements ... 26
10.2 Determination of datum circle ... 27
10.3 Wall plate assembly ... 27
10.4 Installation of moisture-proof plate for double-layer low-temperature storage tanks whose outer tank is reinforced concrete structure ... 34
11 Tank top assembly ... 35
11.1 Center frame method ... 35
11.2 Air lift method ... 36
12 Accessory installation ... 40
12.1 Tank opening and connecting pipe installation ... 40
12.2 Anchor installation ... 40
12.3 Installation of other accessories ... 41
13 Welding ... 41
13.1 General provisions ... 41
13.2 Welding procedure qualification ... 42
13.3 Welding consumables management ... 43
13.4 Welding requirements ... 43
13.5 Welding sequence and method ... 44
13.6 Repair... 46
14 Cold insulation ... 47
14.1 General requirements ... 47
14.2 Cold insulation at tank bottom ... 47
14.3 Tank wall cold insulation ... 49
14.4 Cold preservation of pipelines in the tank ... 50
14.5 Cold insulation of inner suspension roof ... 50
15 Inspection and testing ... 51
15.1 Visual inspection of welded joints ... 51
15.2 Non-destructive testing and tightness test of weld joints ... 51
15.3 Inspection of tank geometry and dimensions ... 54
15.4 Tank test ... 54
16 Construction process technical documents and handover acceptance ... 57 Appendix A (Informative) Several typical structures of low-temperature storage tanks ... 59
Appendix B (Informative) Construction process flow ... 63
Explanation of wording in this code ... 68
Technical specification for construction of vertical
cylindrical low temperature storage tank
This Specification gives the construction process and construction methods of vertical cylindrical low-temperature storage tanks (hereinafter referred to as low-temperature storage tanks); specifies the process control, quality standards, inspection, testing of prefabrication, assembly, welding, cold preservation.
This Specification is applicable to the construction and acceptance of low-temperature storage tanks, which have a nominal volume greater than or equal to 10000 m3 and a design temperature not higher than -45 °C and not lower than -168 °C. Low-temperature storage tanks, which have a nominal volume of less than 10000 m3, can make reference to this Specification.
This Specification is applicable to the construction of low-alloy steel and alloy steel low-temperature storage tanks. Stainless steel low-temperature storage tanks can make reference to this Specification.
This Specification does not apply to the outer tank part of reinforced concrete. 2 Normative references
The provisions in following documents become the provisions of this Standard through reference in this Standard. For the dated references, the subsequent amendments (excluding corrections) or revisions do not apply to this Standard; however, parties who reach an agreement based on this Standard are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest edition of the referenced document applies.
GB 985 Basic forms and sizes of weld grooves for gas welding, manual welding and gas-shielded welding
GB 986 Basic forms and sizes of weld grooves
GB 50236 Code for construction and acceptance of field equipment, industrial pipe welding engineering
JB 4708 Welding procedure qualification for steel pressure vessels - Welding specification for steel pressure vessels - Mechanical proper ty tests of product accordance with GB 50236. Welders engaged in low-temperature steel welding shall undergo skill assessment, before taking up their posts.
3.4 The non-destructive testing personnel engaged in low-temperature storage tanks shall obtain qualification certificates, which are suitable for their work, in accordance with the "Rules on Management of Special Equipment Nondestructive Testing Personnel Assessment and Supervision".
3.5 The construction safety technology and labor protection of low-temperature storage tanks shall be implemented, in accordance with the provisions of SH 3505. 3.6 Refer to Appendix A, for typical structures of single-layer low-temperature storage tanks, steel double-layer low-temperature storage tanks, double-layer low-temperature storage tanks with reinforced concrete outer tanks.
4 Construction preparation
4.1 Technical preparation
4.1.1 The low-temperature storage tank shall have the following technical documents, before construction:
a) Design documents;
b) Quality certification documents for materials and accessories;
c) Construction technical documents;
d) Welding procedure qualification report and welding operation instructions; e) Relevant standard specifications.
4.1.2 Check the drawings, including:
a) Applicability of standard specifications;
b) The connection between the general assembly drawing and the parts drawing, as well as the elevation, orientation, main dimensions, etc.;
c) Construction feasibility of the equipment structure;
d) Connection between equipment drawings and trade drawings such as civil engineering and technology;
e) Requirements for inspection and testing.
4.1.3 Refer to design disclosure.
4.1.4 Conduct technical disclosure, including project characteristics, schedule, construction technology, quality standards, safety and technical labor protection measures, etc.
4.2 Site preparation
4.2.1 Arrange the construction site according to the construction layout drawing. The water, electricity, roads are unimpeded and meet the following requirements: a) The site is flat; there shall be no low-lying water accumulation around the tank foundation;
b) The road shall meet the travel requirements of transportation and hoisting vehicles; c) Material storage facilities shall meet the requirements of construction technical documents.
4.2.2 Provide the construction machinery, tooling facilities, measuring instruments, samples, etc. that meet the requirements for on-site assembly. Measuring instruments shall be within the validity period of the verification.
4.2.3 The construction personnel have undergone safety education and mobilization education.
4.2.4 Configure safety protection facilities, according to the requirements of technical documents.
5.1 The steel materials, accessories, welding materials, cold insulation materials, which are used for low-temperature storage tanks, shall have quality certification documents; their characteristic data shall meet the relevant standards and meet the requirements of the design documents.
5.2 The quality certification documents of low-temperature steel plates, low- temperature accessories, welding materials shall indicate the steel designation, specification, chemical composition, mechanical properties, low-temperature impact toughness value, supply status, material manufacturing standards.
5.3 The manufacturer's sign on the steel surface shall be clear and correspond to the quality certification documents.
5.4 The steel plates used for low-temperature storage tanks shall be checked for 7 Prefabrication
7.1 General requirements
7.1.1 Verification shall be carried out after the template is prepared, which shall meet the following requirements:
a) The template should be made of a metal plate with a thickness of 0.5 mm, reinforced with flat iron or wood; the periphery shall be neat and smooth; b) The chord length of the arc template shall not be less than 2000 mm; c) The length of the straight template shall not be less than 1000 mm;
d) The chord length of the template, for measuring weld corner deformation, shall not be less than 1000 mm;
7.1.2 Check the flatness of the steel plate with a straight template; the gap shall not be greater than 4 mm. The coil shall be flattened and straightened. The straightening should be carried out on a multi-roller plate straightening machine.
7.1.3 Before material marking, check the material and specifications of the steel plate; keep the steel plate in a flat position.
7.1.4 Set the reference line on the steel plate. Draw the cutting line. Mark it with paint marker. Mark the inspection line or inspection point inside the cut line. Mark the equipment position number, arrangement number, specification, material and edge processing symbols, on the steel plate. Before the steel plate is cut, it shall be marked and transplanted; a record shall be made.
7.1.5 The low-temperature steel plate shall not be marked with steel stamps; the non-cutting line shall not be marked with sharp tools; meanwhile it shall not be patterned or punched.
7.1.6 Steel plate groove should adopt mechanical processing. The surface of the groove must not have defects, such as slag inclusion, delamination, cracks, melting slag. 7.1.7 For grooves processed by flame cutting, the surface oxidizing layer shall be removed after cutting. For the steel grooves, which have a standard yield strength greater than or equal to 390 MPa, it shall be subjected to magnetic particle testing according to JB/T 4730.4 or permeation according to JB/T 4730.5. All the tests are qualified with level I. Magnetic particle testing should not be used for the steels that are prone to magnetic deflection during welding.
7.1.8 For steel plates with butt joint thickness greater than 10 mm and steel plates with they shall be clearly marked with a marker pen.
7.7.2 The prefabricated parts shall be packaged, transported, and stored in accordance with the provisions of the construction technical documents.
7.7.3 The following documents shall be provided, when the prefabricated parts leave the factory:
a) List of prefabricated parts (including prefabricated part name, number, material, specification, quantity);
b) Material quality certification documents;
c) Quality certification documents of prefabricated parts;
d) Arrangement plan;
e) Design modification documents.
8 Review of foundation and reinforced concrete outer tank
8.1 Foundation review
8.1.1 The foundation of the low-temperature storage tank shall have obvious markings, such as center position, orientation, elevation.
8.1.2 The foundation shall be re-examined according to the relevant provisions of 8.1.3 and 8.1.4. It shall be installed after intermediate handover.
8.1.3 The surface of the foundation asphalt sand layer shall be flat and dense, without prominent bulges, depressions, through cracks.
8.1.4 The elevation of the center of the foundation and the flatness of the surface shall meet the following requirements:
a) The allowable deviation of the foundation center elevation is ±20 mm; b) For the flatness of the foundation below the wall plate or the flatness of the ring beam, the height difference -- between any two points within the arc length range of 10000 mm -- shall not be greater than 6 mm; the height difference -- between any two points within the circumference length range -- shall not be greater than 12 mm;
c) For the flatness of the asphalt sand layer at the bottom of the tank or the flatness of the concrete layer at the bottom of the tank, concentric circles shall be drawn and the measurement points shall be determined, according to the provisions in 9.3.7 When the edge plate and the medium plate are butt connected, the assembly welding of the edge plate and the medium plate shall be carried out, immediately after cutting off the margin of the medium plate.
9.3.8 For the low-temperature storage tank whose outer tank is concrete structure, if there is a second layer of tank bottom between the inner and outer tank bottoms, the laying, assembly, welding is carried out, after the outer tank bottom is installed AND the cold insulation layer under the second layer tank bottom is finished. After the second layer tank bottom passes inspection, carry out the installation of the cold insulation layer above the second layer tank bottom. Finally install the bottom plate of inner tank. 9.4 Assembly of inner tank bottom of double-layer low-temperature
9.4.1 The installation of the cold insulation layer under the medium plate of the inner tank bottom of the double-layer low-temperature storage tank shall be carried out, after the vault of the outer tank is installed and the rainproof facilities are completed. The assembly procedure of the inner tank bottom is as follows:
a) Installation of cold insulation layer under the edge plate or temporary platform; b) Assembly of edge plate;
c) After the inner tank wall is assembled and the outer vault is installed, lay the cold insulation layer under the middle plate;
d) Assembly of medium plate;
e) Assembly of medium plate with the edge plate.
9.4.2 When the load-bearing and cold-insulation layer under the edge plate is poured on site, the load-bearing and cold-insulation layer shall be cured for 3 days, before the edge plate can be laid and assembled.
9.4.3 When the load-bearing and cold insulation layer under the edge plate is a filling block AND it is required to be installed after the construction of the tank bottom is completed, a temporary platform can be set up at the filling block; the assembled edge plate can be laid on it.
9.4.4 The extraction of the temporary platform and the filling sequence and requirements of the load-bearing and cold-insulation layer filling blocks are as follows: a) Make multiple sets of lifting frames, according to the structure and quantity specified in the construction technical documents;
10.4.2 Welded joints between moisture-proof plates and embedded parts as well as between the moisture-proof plates shall be leak tested by vacuum box method. 11 Tank top assembly
11.1 Center frame method
11.1.1 Assemble the center frame at the center of the storage tank. Place the center top ring of the outer tank roof on the center frame. Install the outer tank vault beam. Lay the outer tank roof plate.
11.1.2 Assembling the tank roof, through the center frame method, shall be carried out according to the following procedures:
a) Assemble the center frame after assembly and welding of the second circle of wall plates of the inner tank; fix it with cables after assembly;
b) Lift the center top ring to the center frame; find out the elevation and center; c) Install the outer tank top pressure ring;
d) Lift the vault beams of the outer tank symmetrically one by one or in groups; weld the two ends to the center top ring and the pressure ring of the outer tank roof, respectively;
e) Install the connecting beams between the vault beams; lay, assemble, weld the tank roof plate according to the plate arrangement plan.
11.1.3 The center frame is made in the form of steel frame; its strength, rigidity, stability shall be determined by calculation. The center position and elevation shall be controlled during assembly.
11.1.4 The assembly of the inner suspended roof can be assembled by full scaffolding method; it can also adopt the hoist lifting method or chain hoist lifting method, meanwhile it shall meet the following requirements:
a) When using the full scaffolding assembly method, the inner suspended roof shall be assembled on the full scaffold with adjusted roof elevation and flatness; then suspended under the arch beam of the outer tank through the suspender; the scaffold and center frame shall be removed after fixing;
b) When hoist lifting method is adopted, the inner suspended roof shall be assembled on the bottom of the tank; a hole shall be opened on the outer tank roof and a pulley block shall be installed; a winch shall be installed outside the tank, to lift the inner suspended roof in place AND fix it;
c) When the chain hoist lifting method is used, the inner suspended roof shall be assembled on the tank bottom; the steel wire rope and chain hoist shall be hung on the main beam of the outer tank roof; the inner suspended roof shall be lifted into place and then fixed.
11.2 Air lift method
11.2.1 The tank roof can be assembled by air lift method, along the outer tank wall or along the inner tank wall.
11.2.2 Assembling the tank roof along the outer tank wall, through the air lift method, shall be carried out according to the following procedures. Meanwhile, the inner tank wall shall be constructed after the outer tank roof is installed in place, by air lift method: a) On the bottom of the outer tank, manufacture and install the outer tank vault beam's support mold; set up a small center frame for assembly; install the center top ring;
b) Assemble the outer tank vault beam on the supporting mold;
c) Reinforce the vault beam of the outer tank;
d) Lay, assemble, weld the tank roof plates;
e) Assemble the inner suspended roof; suspend it on the outer tank roof; f) Install the sealing devices;
g) Set up rainwater drainage device;
h) Install the pressure bearing ring of the outer tank wall; install the limit hanging device on the pressure bearing ring of the outer tank wall;
i) Install the balancing devices;
j) Install the inflatable facilities, air volume adjustment devices, wind pressure measurement devices, etc.;
k) Temporarily connect the anchor structures;
l) Air lift and fix the outer tank roof and the inner suspended roof;
m) Assemble and weld the outer tank vault beams; lay remaining tank roof plates; n) Remove temporary connections of the anchor structures.
11.2.3 Assembling the tank roof by the air lift method along the inner tank wall shall be carried out, according to the following procedures:
a) Assemble the bottom of the outer tank, the bottom ring, the second ring of wall plates;
b) Install the pressure-bearing and cold-preservation layer or temporary platform under the inner tank wall;
c) Lay and assemble the inner tank bottom edge plate;
d) Assemble the inner tank bottom ring and the second ring of wall plate; e) Assemble the outer tank roof and inner suspension roof;
f) Assemble and weld the inner and outer tank walls; assemble and weld