1 Scope
This standard specifies the basic safety requirements for materials, design, pre-fabrication, construction & acceptance, lighting protection, static protection, anti-corrosion and use management, inspection of the vertical cylindrical steel welded tank as well as its safety accessories.
This standard is applicable to the vertical cylindrical steel welded tank with design pressure less than 0.1MPa(G) and nominal volume greater than or equal to 1000m3, which is built on the ground, stores petroleum, petroleum products or chemical liquid media with non-extreme or non-high toxicity, and is subjected to on-site assembly welding. It may be referenced for tanks with nominal volume less than 1000m3 and other similar liquid media.
The scope of the tank to which this standard applies includes a tank body, flange covers for safety accessories and tank connecting pipes, sealing gaskets and fasteners of the sealing gaskets.
This standard does not apply to frozen cryogenic tanks.
2 Normative references
The following referenced documents are indispensable for the application of this standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB 50057 Code for design protection of structures against lightning
GB 50074 Code for design of oil depot
GB 50128 Code for construction of vertical cylindrical steel welded storage tanks
GB 50160-2008 Fire prevention code of petrochemical enterprise design
GB 50183 Code for fire protection design of petroleum and natural gas engineering
GB 50236 Code for construction of field equipment, industrial pipe welding engineering
GB 50341 Code for design of vertical cylindrical welded steel oil tanks
GB 50493 Specification for design of combustible gas and toxic gas detection and alarm for petrochemical industry
GB 50650 Code for design protection of petrochemical plant against lightning
AQ 3028 Safety code for operation at confined spaces in chemical manufactory
HG 20660 Standard for classification on hazards of toxicity and explosion of chemical mediums in pressure vessel
GBZ 230 Classification for hazards of occupational exposure to toxicant
JB/T 4730 NDT of pressure equipments
JB/T 10764 Non-destructive testing - Acoustic emission testing and evaluation of atmospheric pressure metal storage tanks
JB/T 10765 Non-destructive testing - Magnetic flux leakage testing of atmospheric pressure metal storage tanks
NB/T 47014 Welding procedure qualification for pressure equipment
NB/T 47018 Technical permission of welding materials for pressure equipment
SH/T 3007 Design specification for tank farms of storage and transportation system in petrochemical industry
SH/T 3026 Standard for aseismic appraisal of atmospheric vertical cylindrical storage steel tanks
SY/T 6620 Tank inspection, repair, alteration and reconstruction
TSG Z6002 Examination rules for welding operators of special equipment
API Std 2000 Venting Atmospheric and Low Pressure Storage Tanks (Nor-refrigerated and Refrigerated)
3 Terms, definitions and abbreviations
For the purposes of this document, the following term, definition and abbreviations apply.
3.1 Terms and definitions
3.1.1
tank body
tank body includes:
a) beveled end face of the first circumferential joint in welded connection with an outer pipeline;
b) end face of the first threaded joint in threaded connection;
c) first flange sealing surface in flanged connection;
d) first sealing surface connected with a special connecting piece or a pipe fitting;
e) connection welds between the tank and non-pressure elements.
The main pressure elements in the tank body include roof, shell, tank bottom, connecting pipes and pipe flanges with nominal diameter greater than or equal to 250mm
3.1.2
safety accessory
safety accessory of the storage tank includes safety valve/breathing valve, emergency cut-off device, safety interlock device, pressure gauge, liquid level meter, thermometer, flame arrester
3.1.3
design positive pressure
set maximum pressure of the gas-phase space of roof, which, together with corresponding design temperature, is taken as the design load condition
3.1.4
design negative pressure
set maximum external pressure (excluding the external pressure caused by wind load) bore by the tank or the maximum local vacuum degree in the tank. Design negative pressure shall not be less than the maximum local vacuum degree possibly achieved in the tank (its value shall be determined by the vacuum degree formed by a vacuum relief valve at the maximum specified flow rate)
3.1.5
design temperature
under normal working condition of the tank, the set metal temperature (average temperature along the section thickness of an element) of a tank shell plate and a stressed element shall be taken as the design load condition together with corresponding design pressure.
3.1.6
large storage tanks
tanks with nominal diameter greater than or equal to 30m or nominal volume greater than or equal to 10000m3
3.1.7
internal inspection
inspection conducted on various parts or components such as tank bottom after the medium in the tank is emptied, during which an inspector usually needs to enter the tank
3.2 Abbreviations
3.2.1
RBI: Risk Based Inspection
3.2.2
WPS: Welding Procedure Specification
3.2.3
TOFD: Time of Flight Diffraction
Foreword I
1 Scope
2 Normative references
3 Terms, definitions and abbreviations
4 General
5 Materials
6 Design
7 Prefabrication, construction and acceptance
8 Lightning protection and static protection
9 Anti-corrosion
10 Utilization management
11 Tank inspection
12 Safety accessories
Annex A (Normative) Classification of tank pressure grade
Annex B (Normative) Classification method of storage tanks
Annex C (Informative) Tank product nameplate
Annex D (Informative) Tank product data sheet
Annex E (Informative) Fire hazard classification
Annex F (Informative) Tank product certificate
Annex G (Normative) Tank code numbering method
Figure C.1 Tank product nameplate
Figure G.2 Schematic diagram of equipment code
Table D.1 Tank product data sheet
Table E.1 Fire hazard classification of flammable liquid
Table F.1 Tank product certificate
