4.3　Plant Area Planning and General Layout

4.3.1　The planning of plant area shall follow the principle of making process flow reasonable,and shall take the main power house as the center,clearly divide functional zones by considering production facilities and process systems,realize compact and reasonable layout and create favorable condition for further extension,as well as satisfy the requirements for fire/explosion protection,environmental protection and labor safety&occupational hygiene.The buildings in the front area of plant should be arranged centrally and convenient for living and link with production.The extension/betterment project for an existing fossil fired power plant should utilize the existing plant site and available facilities.

4.3.2　The arrangement of buildings（structure）in the plant area shall comply with the current national standard GB 50016,Code of Design on Building Fire Protection and Prevention and GB 50229,Code for Design of Fire Protection for Fossil Fuel Power Plant and Substation,and shall comply with the following requirements:

1　The main power house,chimney,cooling tower and circular closed coal yard should be arranged on the ground with uniform soil stratum and high bearing capacity.If once-through water supply mode is adopted,the turbine house should be near the water intake.If direct air cooling units are adopted,the main power house shall be located according to the effects of meteorological conditions on the operation of air cooling units.

2　The incoming and outgoing lines of indoor and outdoor HV switchgear installations shall be routed unobstructedly and should avoid crossing each other.Also,the routing shall be convenient for extension.

3　The cooling tower shall be arranged by comprehensively considering the topography,geology,circulating water pipeline length,layout of adjacent facilities and prevailing wind direction.For the project that can be extended,the cooling tower should not be arranged at the extension end of the main power house.

4　The outdoor coal yard and liquid ammonia storage facilities should be located at the windward side of the all-round-the-year minimum frequency of wind direction of main buildings in the plant area,and prevent their pollution to the residential areas outside the plant.

5　The areas exposed to bare parts of outdoor HV switchgears shall be covered with lawn,gravel,or cobble.Coal yard,ash silo,desulphurization absorbent storage site,and other areas causing dust entrainment shall be provided with dust prevention measures.The areas below the platform carrying direct air-cooling system should be made of concrete floor.

6　Hydrogen generation（supply）stations,fuel oil facilities,and liquid ammonia storage facilities shall be arranged separately from other production,auxiliary and ancillary buildings,forming respective independent areas.

7　If fuel oil facilities and liquid ammonia storage facilities are arranged close to rivers or lakes,measures shall be taken to prevent the liquid from leaking into the water area.

8　There shall be no less than two accesses to the plant area.They shall be located to facilitate internal and external communication and separate pedestrian and freight flow.The main access should be located at the fixed side of the plant area.

4.3.3　The spacing between the buildings（structures）of a fossil fired power plant shall comply with relevant regulations of GB 50229,Code for Design of Fire Protection for Fossil Fuel Power Plant and Substation,DL/T 5032,Technical Code of General Plan Transportation Design for Fossil Fuel Power Plants,GB 50177,Design Code for Hydrogen Station and GB 50074,Code for Design of Oil Depot,in addition to the following requirements:

1　The arrangement spacing between liquid ammonia storage facilities shall comply with the relevant stipulations regarding the arrangement of Type B liquid storage tanks in the current national standard GB 50016,Code of Design on Building Fire Protection and Prevention.

2　The spacing between mechanical draft cooling towers shall comply with the current national standard GB/T 50102,Code for Design of Cooling for Industrial Recirculating Water.

3　The minimum horizontal distance from overhead high voltage side-conductor exposed to wind deflection effects to the Type C,D,and E buildings（structures）shall be 4m for 110kV,5m for 220kV,6m for 330kV,8.5m for 500kV,11m for 750kV,and 21m for 1000kV.The high voltage transmission lines should not cross permanent buildings；if it is unavoidable,the requirements on the minimum electric clearance shall be met,and corresponding fireproof measures shall be taken on the building roof.

4.3.4　In case of fossil fired power plants employing air-cooling units,the air-cooling facilities shall comply with the following requirements:

1　The orientation of platform carrying direct air-cooling system shall be determined according to the direction,speed and frequency of prevailing wind in a year,in summer season and in the extremely hot and windy summer days.It shall also incorporate the process arrangement requirements and take into account the safety and economy of operation of air cooling units.

2　The platform carrying direct air-cooling system should be located outside column A of the main power house.The transformer,electrical switchgear room,and oil storage tanks may be arranged under the platform provided that the platform columns will not affect the installation of transformers and fire fighting and maintenance accesses.

3　The indirect air-cooling tower should be arranged close to the turbine house side except where it serves as a flue gas discharged cooling tower.

4.3.5　For a fossil fired power plant that adopts flue gas discharged cooling tower,the cooling tower should be arranged close to the boiler rear.

4.3.6　For a fossil fired power plant that adopts mechanical draft cooling towers,the air inlet side of single-side air inlet towers should face toward the prevailing wind direction in summer,while the air inlet side of double-side air inlet towers should be in parallel with the prevailing wind direction in summer.

4.3.7　The design criteria of the railway inside a fossil fired power plant shall meet the following requirements:

1　The railway shall be planned in a unified way and constructed in stages according to the principles of direct arrival of a whole train and direct connection between railway and enterprises,and the long-term development plan of railway.

2　When using reciprocating type wagon tipplers to unload coal,each tippler shall be provided with one loaded track,one empty track and locomotive running track shall be arranged reasonably.

3　When using slot type coal hoppers to unload coal,the number and effective length of unloading tracks shall be determined according to the daily maximum number of coal-loaded trains,attached wagon number,unloading port number,and site conditions.The track should be made into a through track and locomotive running tracks shall be reasonably provided.

4　The in-plant tracks shall have an effective length to satisfy the traction capability required by railways outside the plant area,and shall be arranged according to the needs for arrival and departure of a whole train on the unloading tracks in the power plant.

5　When the loaded track and empty track in the plant area are designed for unloading a whole train,no standby loaded-wagon track,shunting track,or other track for wagon arrival-departure shall be provided.

4.3.8　The construction scale and general layout of coal wharf of a fossil fired power plant shall be planned in a unified way and the wharf shall be constructed in stages according to the planning capacity of the power plant,the construction scale of current phase,natural conditions of the plant site and waterways,and the coal handling facilities in the plant,and shall observe the following regulations:

1　The planning and design of wharf shall comply with the current national standard GB 50192,Code for Design of River Port Engineering and JTJ 211,Design Code of General Layout for Sea Port.

2　The wharf shall be located at sections with appropriate water depth,stable waterway,weak sediment movement,smooth flow,and good geology,and should be coordinated with the on-shore elevation.

3　There shall be sufficient open water areas in front of the wharf.The distance between the wharf and the inlet and outlet of once-through cooling water supply system shall be sufficient to avoid mutual effects,and shall be sufficiently demonstrated and reasonably determined through model tests.

4.3.9　If a wharf for large and heavy equipment transportation is built by the fossil fired power plant itself,the wharf shall be designed to satisfy the transportation for both large and heavy equipment and other raw material or by-products during the operation of the power plant.

4.3.10　For a fossil fired power plant that receives coal transported by highways,the accesses for trucks shall be located to facilitate the connection to external dedicated coal transportation roads,and a parking area should be appropriately provided between the loaded vehicle access and the weighing machine.The roads in the coal unloading facility area shall be planned such that the loaded vehicle flow and empty vehicle flow will not interfere with each other.The sampling device should be preceded by the weighing machine.

4.3.11　The design of roads in the plant area shall comply with the current national standard GBJ 22,Code for Design of Roads in Factories and Mining Areas.Traffic lane,fire lane and pedestrian way shall be provided between buildings in the plant area according to the requirements of production,operation,maintenance,living and fire protection.In addition,the regulations below shall be followed:

1　The main power house,coal yard,hydrogen generation（supply）station,liquid ammonia storage area,and fuel oil facilities area as well as the outdoor switchgear area shall be provided with ring-shaped fire lanes.If it is difficult to provide ring-shaped fire lanes in the main power house,fuel oil facilities area,liquid ammonia storage area and coal yard of a fossil fired power plant in mountainous area,the fire lane may be of dead end type with a turnaround along the long side.The turnaround shall cover an area no less than 12m×12m,or 18m×18m when it is used for large fire vehicles.

2　The fire lane in the plant area shall have a width no less than 4m,and a clear height no less than 4m if there are pipe racks,trestles,or other obstacles above the lane.

3　The width of the ring-shaped road around the main power house and the travel lane of an arterial road for handling coal,limestone,ash,gypsum,combustion-supporting oil,and liquid ammonia in the plant area should be 7m,or 6m if it is impracticable；and the width of minor roads should be 4m,or 3.5m if it is impracticable.

4　For a fossil fired power plant built with wharf for transportation of large and heavy goods,the standard of roads between the approach bridge to the heavy goods wharf and the ring-shaped road around the main power house shall be properly determined according to the requirements for transporting large and heavy goods,and its width should be 6-7m and the turning radius should not be less than 12m.

4.3.12　The boundary walls of the plant area shall be arranged as orderly as possible on the premises of occupying the minimum land,and,unless there are some special requirements,should be of solid enclosure walls of no less than 2.2m in height.The enclosure walls or fences around relevant functional areas shall be arranged in compliance with the following requirements:

1　The in-plant parts of outdoor HV switchyard and the transformer yard shall be provided with 1.8m high and 1.5m high fences respectively.

2　The hydrogen generation（supply）station area,liquid ammonia storage area,and fuel oil facilities area shall be separately provided with non-combustible enclosure wall no lower than 2.5m in height,noncombustible enclosure walls no lower than 2.2m in height,and 1.8m high fences respectively.If the above areas utilize the enclosure walls of the plant area,non-combustible solid enclosure walls no lower than 2.5m in height shall be adopted.

4.3.13　The land area occupied by a plant area shall comply with the relevant national regulations in force.The building coverage shall be no less than 35%and the green space ratio shall be no more than 20%.

4.3.14　The plant site elevation of a fossil fired power plant shall comply with the requirements of flood control standards specified in Table 4.3.14.

4.3.15　In case the plant area is affected by flood,water logging and storm surge,flood（surge）prevention measures shall be taken and in compliance with the following regulations:

1　If the site elevation is lower than the design high water（tide）level,or if the plant site is affected by waves although the site elevation is higher the design high water（tide）level,the plant area shall be provided with dam or other reliable flood prevention measures,and shall comply with the following requirements:

1）For the power plants located at sea beach,the top elevation of their flood embankment（or water break）shall be determined to be the design high water（tide）level plus the wave run-up of 1%accumulative frequency recorded within 50 years of return period,and plus 0.50m freeboard for safety.It is demonstrated that if the overtopping has no effects on the safety of dam and can be smoothly drained after the dam,the top elevation of dam may be determined to allow for partial overtopping；and the top elevation,cross-sectional size and pavement structure of dam should be determined through physical model tests.

2）For fossil fired power plants close to river and lake,the top elevation of flood embankment shall be 0.50m higher than the design high water level.If the power plants are likely to be significantly influenced by wind,wave and tide,the wave run-up within 50 years of return period shall be added.

2　If a power plant is to be built in the area where there is potential water logging,the top elevation of embankment for water logging prevention shall be determined to be the water logging water level occurred in 100-year return period（when it is difficult to determine,the highest water logging level in history shall be adopted）plus 0.5m extra height for safety.If flood drainage facilities are available,it shall be determined to be the design water logging level plus 0.50m extra height for safety.

3　For fossil fired power plants located in mountainous areas,flood prevention and drainage measures shall be taken based on 100-year return period design flood level.

4　When a fossil fired power plant is located at the downstream of a reservoir,and the flood control standard of the reservoir is lower than that of the power plant or the reservoir is a devastated and dangerous one,if the flood caused by reservoir dam-break may affect the plant area,corresponding engineering measures shall be taken.

5　The flood prevention and drainage facilities should be completed once for all in initial phase of the project according to the planning capacity.

4.3.16　The vertical arrangement of the plant area shall be comprehensively determined according to the production process requirements,engineering geology,hydro-meteorological conditions,earthwork quantities and ground treatment,and shall comply with the following requirements:

1　For the power plant area without dam or embankment,the design elevation of the ground outside the main power house shall be 0.5m higher than the design high water level.For the plant area provided with dam meeting the requirements on flood prevention and reliable anti-water logging measures,the elevation of plant site may be properly lower than the design flood level.

2　The elevations of buildings（structures）,railway and roads shall satisfy the requirements on production and maintenance and shall allow unobstructed water drainage.

3　The indoor floor level of buildings shall be determined by comprehensively considering the architectural function,transportation,site drainage,and site geological conditions,and should be 150-300mm higher than the outdoor ground design level.In soft soil areas,the effects of indoor/outdoor differential settlement shall be included in the design calculation.

4　The vertical design of plant area should ensure the balance of cut and fill of earthwork within the plant area and the construction site.In case the backfilled volume and excavation volume cannot be balanced,the borrow area and spoil area shall be determined,and should be taken into consideration in conjunction with other borrow and spoil projects in the area where the project is located.

5　The minimum slope and inclination direction of the ground in the plant area shall be capable of quick drainage of surface water,and shall be adaptable to the positions of rainwater catch basin,gutter of the buildings,roads and ground,and shall be determined according to the local rainfall amount and soil condition of the site.

4.3.17　If the natural slope of topography of the plant area is above 3%,stepped arrangement should be adopted.The stepped arrangement shall be determined according to the requirements of production and convenient transportation,reasonable layout of underground facilities and stable slope.

4.3.18　The design of drainage system in the plant area shall be determined taking into account the local landform,engineering geology,hydrometeorology,ground water level,in conjunction with the planning capacity.

4.3.19　The pipelines in the plant area shall comply with the requirements below:

1　The main pipe supports,pipelines and pipe trenches shall be planned from an overall view and arranged in centralized way based on the planning capacity,and should be built in stages,and there shall be adequate pipeline corridor.

2　The pipelines shall be arranged according to the requirements of reasonable process flow and allow for convenient construction and maintenance.

3　Any faults on pipes shall not cause secondary disaster.Especially,measures shall be taken to prevent the sewage from infiltrating into the feed water pipes and prevent harmful or inflammable gas from penetrating into other channels and basements.

4　The pipelines shall be protected against mechanical damages and corrosion.

5　Reliable water collection and drainage facilities shall be provided for underground trenches（tunnels）.

6　Fire walls shall be built at places where cable trench and cable tunnel enter into the buildings or shall be built at appropriate intervals and sections,and fire doors shall be provided in the fire walls of cable tunnel.

7　Pipe supports,pipelines and trenches should be laid along roadway and underground pipelines and trenches should be away from the roadway on which vehicles run.In areas where the seismic intensity is 8 degree and above,the rainwater pipes and sewage pipes shall not be laid in parallel below the roadway on which vehicles run.

4.3.20　The laying of the pipeline in plant area shall conform to the following regulations:

1　For pipelines that can be arranged overhead centrally as the condition permit,combined pipe supports should be adopted；in regions where underground water level is relatively high,earth is corrosive or the embedded depth of bed rock is relatively less thus being unfavorable for construction of underground pipeline,combined pipe supports should be adopted preferably.

2　The pipes delivering water for production,living and fire fighting purpose and the pipes for draining rainwater and sewage water should be laid underground.The pipes delivering water for production,living purpose may be laid overhead,but shall be provided with reliable anti-freezing and thermal insulation measures in extremely cold regions.

3　The pipes delivering ash,limestone slurry,gypsum slurry,hydrogen gas,compressed air,combustion-supporting oil,ammonia gas and steam should all be laid overhead.

4　The pipes delivering acid liquor and caustic liquor may be laid either in trench or overhead.The pipes likely to worsen situations in the event of accidents should not be laid in one ditch.

5　The cables in the plant area may be laid by directly burying them,overhead or in trenches,duck banks and tunnels.

The cables shall not be laid with other pipes in one same trench.

6　If hydrogen gas pipelines,ammonia gas pipelines are laid together with other pipelines on the same rack,the hydrogen gas pipelines,ammonia gas pipelines shall be at the outside and at the top layer.

7　The inflammable and explosive pipes shall not be laid on the roof or external wall racks of unrelated buildings.

4.3.21　The horizontal distance from pipe trench and underground line to building,structure,railway,road and other pipelines and the vertical distance at intersections shall be determined according to the buried depth of the underground line and pipe trench,foundation structure of building,and requirements of construction and maintenance.