1 General provisions
1.0.1 This code is formulated with a view to standardizing the design of water supply and drainage piping engineering in chemical industry, improving the quality of engineering design, and achieving comprehensive planning, rational layout, advanced technology and economical rationality.
1.0.2 This code is applicable to design of constructed, extended or renovated piping of water supply and drainage in chemical industry.
1.0.3 In addition to this code, the design of piping of water supply and drainage in chemical industry shall also meet the requirements of the current relevant standards of China.
2 Terms
2.0.1 piping system
a group of pipes formed by connecting a plurality of pipes divided according to fluid and design conditions
2.0.2 flume
arc-shaped water groove set inside the inspection well to keep the flow state stable and avoid the vortex phenomenon caused by any change in section
2.0.3 covered depth
vertical distance from the outer top of the buried piping or pipeline to the ground surface
2.0.4 buried depth
vertical distance from the inner bottom of buried piping or pipeline to the ground surface
2.0.5 surge or water hammer
hydraulic impact phenomenon, in pressure pipeline, of alternating pressure rise and fall caused by the drastic change of flow velocity
2.0.6 cathodic protection
electrochemical protection method, taking metal as cathode for protection with the aid of external anode or DC power supply to avoid pipe corrosion
2.0.7 flexible joint of piping
pipe joint allowing a certain amount of axial line and relative angular displacement
2.0.8 composite pipe
round pipe with wall structure consisting of two or more kinds of materials
3 Piping system and layout
3.1 General requirements
3.1.1 The division of the water supply piping system shall be determined according to the requirements of the process plant for water quality, water pressure and water temperature.
3.1.2 The division of water drainage piping system shall be determined based on classification of water quality, in the principle of separation of clean water and wastewater and according to the water quality, water volume, water pressure and destination of drainage. For wastewater of different properties discharged by different chemical process plants (units), separate or combined wastewater piping system shall be set up in the principles of easy transport and treatment. Separate wastewater piping system should be set for the following types of wastewater:
1 wastewater prone to precipitation, polymerization or formation of refractory substances resistant to biodegradation;
2 wastewater containing high concentration of refractory substances resistant to biodegradation and biological toxic substances, thus requiring targeted treatment;
3 wastewater containing corrosive media such as acid and alkali;
3.1.3 Independent fire water supply piping must not be connected to non-fire water piping.
3.1.4 The fire water supply system shall not be combined with the circulating cooling water system.
3.1.5 The circulating cooling water piping should not be connected with other production water supply piping.
3.1.6 The recycling water system shall be provided with independent water supply piping.
3.1.7 Independent drainage piping system should be adopted for domestic drainage in the plant.
3.1.8 Emergency fire-fighting drainage piping in polluted areas such as production plant and tank farms may be combined with production sewage piping and rainwater piping (pipeline) or set independently, but shall not pass through explosion-proof areas; if it is unavoidable, protective measures shall be taken.
3.1.9 As for the piping of water supply and drainage of a process plant (unit), the number of inlets and outlets and the orientation shall be determined according to the piping layout within the process plant (unit) and the layout of overall piping of water supply and drainage.
3.1.10 The piping of sewage containing flammable liquid shall be set in accordance with the requirements of the current national standard GB 50160 Fire prevention code of petrochemical enterprise design.
3.1.11 The fire water supply piping and its facilities shall be set in accordance with the relevant requirements of the current national standards GB 50160 Fire prevention code of petrochemical enterprise design and GB 50016 Code for fire protection design of buildings.
3.1.12 If the outlet of gravity drainage piping is jacked by water flood or tide water level, anti-backflow facilities shall be set.
3.1.13 The drainage piping system in the plant area shall be provided with emergency facilities to prevent accidental fire fighting wastewater from flowing into the off-plant environment.
3.1.14 Water hammer analysis and calculation should be carried out for pressure transport piping. If water hammer generated may endanger the piping safety, measures shall be taken to diminish water hammer.
Foreword i
1 General provisions
2 Terms
3 Piping system and layout
3.1 General requirements
3.2 Piping system
3.3 Piping layout
4 Ancillary structures
4.1 General requirement
4.2 Valve well and fire hydrant well
4.3 Inspection wells
4.4 Water-sealed well
4.5 Drop well
4.6 Gutter inlet
4.7 Inverted siphon piping
4.8 Outlet
5 Hydraulic calculation
6 Pipe materials and connection
6.1 Pipe material
6.2 Pipe connection
7 Pipe support, hanger and foundation
7.1 General requirements
7.2 Supports and hangers of pipes
7.3 Pipe foundation
8 Pipe anti-corrosion and heat insulation
8.1 Anti-corrosion
8.2 Heat insulation
Explanation of wording in this code
List of quoted standards
