Chapter 7 : Utility Services
2.1 General 2.2 Electric Substations 2.3 Overhead Transmission Lines 2.4 Underground Cables 3.1 General 3.2 Piped Gas Supply 3.3 Guidelines on Provision 4.1 General 4.2 Telephone Network 4.3 Telephone Exchanges 5. Radio and Broadcast Communications 5.1 General 5.2 Guidelines on provision 6.1 General 6.2 Locational Guidelines 7.1 General 7.2 Foul Sewerage System 7.3 Stormwater Drainage System
April 2002 Edition
1.1 The provision of utility services is fundamental to modern living. From a town planning point of view, utility services are components of the basic infrastructure. The planning of their provision should be integrated into the overall planning of new development areas such that the efforts between various government departments and utility companies can be co-ordinated. 1.2 This chapter provides planners with the basic information on electricity supply, gas supply, telephone service, radio and broadcast communication, water supply and drainage services. The guidelines would help planners in understanding the requirements of utility services/facilities and enable them to work with various departments and utility companies in the planning of new development areas.
2.1 General 2.1.1 Electricity supply is currently provided by the Hongkong Electric Company Limited (HEC) (for Hong Kong Island and the neighbouring islands of Ap Lei Chau and Lamma) and the CLP Power Hong Kong Limited (CLP Power) (for the whole of Kowloon, the New Territories and a number of outlying islands including Lantau). 2.1.2 Electricity supply facilities include power generating stations, electric substations, overhead lines and underground cables. Only the latter three items are discussed because power generating stations are major territorial facilities requiring special investigations on each project. 2.2 Electric Substations 2.2.1 Electricity is transmitted and distributed by different types of electric substations. The CLP Power network includes extra high voltage (EHV) substations, bulk infeed substations (BISs), primary substations and consumer's substations. The HEC network includes bulk infeed substations, primary substations and consumer's substations. The substations' characteristics are discussed below:- (a) Extra High Voltage Substations & Bulk Infeed Substations (Switching Stations)
(b) Primary Substations (Zone Substations)
(c) Consumer's Substations (Distribution Substations)
2.2.2 Sufficient number of primary substations and BISs are required to meet all the 22kV and 11kV loads in a supply area. In order to meet the demand for electricity supply in a new town or re-developed area on time, it is recommended that the relevant utility company be advised of the scale of development at an early planning stage. CLP Power or HEC will investigate if demand can be met by the existing primary substations and BISs, or new ones are required. With respect to the access, parking and loading/unloading arrangements, Transport Department should be consulted at an early planning stage. Please refer to Table 11 of Chapter 8 for parking and loading/unloading requirements. Guidelines on Provision 2.2.3 Extra High Voltage Substations & Bulk Infeed Substations (Switching Stations)
2.2.4 Primary Substation (Zone Substations)
2.2.5 Consumer's Substation (Distribution Substation)
2.3 Overhead Transmission Lines Guidelines on Provision 2.3.1 The location of new pylons and overhead transmission lines (OHL) should not be permitted to dictate the pattern of future land use or to sterilize land which has a good development potential. If the land is required for development, the existing transmission lines, unless part of an approved scheme which is the subject of an order under the Electricity Networks (Statutory Easements) Ordinance, may have to be relaid underground or re-routed. However, the high cost involved in diversion should be given due consideration. 2.3.2 They should not be erected in existing developed areas, areas having substantial development potential, and public open space, as far as practicable. Except in very special circumstances, environmentally sensitive areas such as Sites of Special Scientific Interest (SSSI), conservation areas and country parks should also be avoided. 2.3.3 Early consultation with the concerned departments at the planning stage is essential, particularly on matters relating to locations of pylons and OHLs. For extra high voltage transmission lines e.g. 400 kV, detailed site search reports with full justifications should be prepared for consideration of relevant departments. Environmental Considerations 2.3.4 When the erection of permanent OHLs and pylons is planned, a prudent approach should be adopted taking into account the following principles and environmental considerations:
Safety Considerations 2.3.5 For electrical safety considerations, provision should be made for physical separation between conductors and adjacent buildings/structures. Depending on the design of the structures supporting the conductors, the safety clearance should take the magnitude of swing of conductors due to wind deflection into account. The respective minimum safety clearances for various voltage levels of conducts (except 275kV and 22kV which are conducted by underground cables) are given in Table 1.
2.3.6 Moreover, in the design of OHLs, adequate vertical ground clearance, which is measured from the lowest point of the conductors (sagged point due to gravity) to the ground level, should be provided. The determination of the minimum vertical ground clearance should take the statutory requirements as laid down in the Electricity Supply Regulations into account. The respective figures for various voltage levels are given in Table 2.
2.3.7 The figures given in Tables 1 & 2 are for general reference purpose. To prevent confusion and possible misinterpretation of the data, early consultation with the power company and the Electrical and Mechanical Services Department (EMSD) will be necessary for their application. Additional allowance for the safety clearance may be required by EMSD to suit the actual site conditions. 2.3.8 In addition to the minimum safety clearance, allowance for the provision of a 6m emergency vehicular access may be required, for fire fighting purposes, to reach the principal face of any adjacent building development. Since each case will be considered on its merits, consultation with the D of FS will be required regarding the detailed arrangement. 2.3.9 To illustrate the above requirements, schematic drawings for 400kV and 132kV OHLs supported on pylon are given in Figure 1, Figure 2, Figure 3 and Figure 4 respectively. Health Considerations 2.3.10 The electric and magnetic fields (EMF) emanating from OHLs are at extremely low frequency (50Hz) known as power frequency EMF. Although there is no conclusive scientific evidence to date to support the hypothesis of adverse health effects arising from exposure to power frequency EMF, the EMF exposure limit promulgated in the guidelines issued by the International Commission on Non-ionizing Radiation Protection (ICNIRP)(2) in 1998 are generally adopted as a prudent avoidance against the influence of power frequency EMF. The development and research carried out on the subject are closely monitored by departments concerned and the power companies. 2.3.11 In line with the guidelines issued by ICNIRP in 1998, the following standards on the continuous public exposure limits for power frequency electric and magnetic fields are recommended to the power companies by EMSD when the erection of permanent overhead transmission lines is planned:
The power companies should seek further advice from EMSD at the design and planning stages of the overhead lines concerned. Footnotes : (2) ICNIRP: The International Commission on Non-ionizing Radiation Protection (ICNIRP) was established in 1992 as a successor to the International Non-ionizing Radiation Committee of International Radiation Protection Association (IRPA/INIRC). The functions of the Commission are to investigate the hazards that may be associated with the different forms of the non-ionizing radiation, develop international guidelines on non-ionizing radiation limits, and deal with all aspects of non-ionizing radiation protection. (3) Electric Field Strength: This is the force exerted by an electric field on a medium. Its magnitude is directly proportional to the voltage of the source and diminishes with distance away from the voltage source. The electric field strength is expressed in terms of volts per metre or kilovolts per metre. (4) Magnetic Flux Density: This is the magnetic flux per unit area at a point in a magnetic field. Magnetic flux is produced by electric current passing through a wire. Its magnitude is directly proportional to the current and diminishes with distance away from the current source. The unit of the magnetic flux density is microteslas or milliteslas. 2.3.12 In general, the physical separation provided by the preferred working corridor (para. 2.3.13 refers) has made allowance for the above consideration. However, at the early planning stage of the OHLs, the power company concerned should provide the necessary information to the EMSD for consideration. Preferred Working Corridor of Overhead Transmission Lines 2.3.13 For route protection and to provide sufficient space for pylon erection, operation, inspection, maintenance, repair, renewal and removal of the equipment, a "preferred working corridor" (as shown in Figure 1 and Figure 3) following the alignment of the OHLs, will be required for general planning purpose. In the case of pole lines, in addition to the "preferred working corridor", a "preferred working circle" is required for pole erection as shown in Figure 5 and Figure 6. 2.3.14 The respective width of the preferred working corridor for 400kV and 132kV OHLs supported on pylons are given in Table 3 and Figure 1 and Figure 3.
Note: Some of the 132kV OHLs are supported on pylons 2.3.15 For conductors supported on poles, e.g. voltage level from 132kV downwards, in addition to the preferred working corridor, space is needed as a "preferred working circle" to facilitate pole erection. The height of the pole has been taken into account in determining the radius of the circle. In general, the alignment of OHLs and the location of the supporting poles should avoid existing settlements as far as possible. The respective figures of preferred working corridor and working circle for 132kV, 66kV, 33kV and 11kV OHLs supported on poles are given in Table 4.
2.3.16 Schematic drawings for 132kV OHLs supported on poles are given in Figure 5 and Figure 6. 2.3.17 Building developments will not be restricted in areas outside the preferred working corridor and working circle subject to the provision of emergency vehicular access, wherever appropriate, as required by Fire Services Department (FSD). For development within the preferred working corridor and working circle, agreement from the EMSD, FSD and the power company should be sought in order to ensure compliance of the safety and health considerations as given above. 2.3.18 For example, N.T. village house development underneath 400kV OHLs will be possible provided that the height of the conductors (sagged portion) is designed not less than 15.6 m above the ground level. This clearance makes allowance for the maximum height of the village house (8.23 m) and the average height of an antenna (1.87 m) such that the minimum safety clearance of 5.5 m between antenna and the 400kV conductors is maintained. However, agreement must be obtained from EMSD, FSD and the power company before the commencement of any development or building works. An illustrative sketch is given in Figure 7 . 2.3.19 Notwithstanding the above, the Land Authority should also notify the power company concerned of any development (permanent or temporary) that is proposed within a distance of 45m from overhead transmission lines. Separation from Telecommunication Lines on support 2.3.20 The alignment of the OHL should be separated from other telecommunication lines e.g. telephone, on support. Reference should be made to the "Code of Practice - Protection of Communication Networks From Electrical Power Distribution" issued by the Director-General of Telecommunications (DG, OFTA) and OFTA. 2.4 Underground Cables 2.4.1 Cables are normally laid directly underground. Road openings to facilitate installation of cables are subject to permission from the Highways Department. Projects requiring large scale excavation are also subject to approval from Land Authority and other Government bodies concerned. 2.4.2 Minimum separation between power cables and telephone cables is 0.3 m wherever practicable. Details can be obtained from the DG, OFTA.
3.1 General 3.1.1 The Government's policy is to ensure, as far as possible, the provision of a piped gas supply to domestic consumers, particularly to new building developments, as a means of discouraging the future growth of liquefied petroleum gas cylinders. In this regard, a piped gas supply in the form of town/natural gas or from a bulk liquefied petroleum gas (LPG) storage installation should be planned for all new developments. 3.1.2 The Gas Safety Ordinance (Cap. 51) and its subsidiary regulations which became effective on the 1st April 1991 must be complied with when a gas supply is considered. 3.2 Piped Gas Supply 3.2.1 A piped gas supply can be made available by:
3.2.2 The advice of either the Hong Kong & China Gas Co. Ltd. (for town/natural gas) or the potential LPG supplier (for LPG) should be sought at the earliest possible stage in the design of the development or redevelopment proposals. 3.3 Guidelines on Provision Town/Natural Gas 3.3.1 The production, storage and distribution of town/natural gas require the building of gas works, gas holder stations, pressure reduction equipment and a pigging system ranging from high to low supply pressures. Gas works and gas holder stations are very specialized facilities and need to be dealt with on an individual basis, taking account of hazard assessments. Gas pressure reduction station installations are required for reducing the pressure from a higher pressure pipeline system to a lower pressure system. The site area required for installing the pressure reduction equipment is dependent on operation requirements and can vary from 12m2 to 2000m2. Generally, the supply pipes should be laid underground, however, due to various technical reasons, alternative installation methods may be considered. As for the location and safety separation distance requirement for pipelines, the EMSD (Gas Standards Office) is the authority to advise. No supply pipes should be accommodated in a highway structure which is a sole access or carries a strategic route. However, consideration should be given to waive the constraint when there is no alternative route. Close liaison between Highways Department and the gas company at the early planning stage will be necessary in identifying an acceptable routing arrangement. Centralized LPG supply Installations 3.3.2 A permanent site located within the development areas being served is required. However, the size of the storage area required, the safety distances needed, and the laying of pipes would be subject to advice of the EMSD (Gas Standards Office). As a general rule, the installations should be secure, sited in a well ventilated area and accessible by vehicles for replenishment and emergency service. Substitute Town/Natural Gas 3.3.3 A temporary LPG/Air mix plant could be located in the vicinity of the township or development being served but not necessarily immediately adjacent to it as substitute town/natural gas can be supplied over long distances by underground pipelines. However, the plant should be located in a well ventilated area where other utility services, such as water and electricity are available and accessible by vehicles for replenishment and emergency service. Whilst the gas production installation itself is temporary, the reticulated supply system is permanent and could be connected with the town/natural gas supply subsequently. The location and site area of a LPG/air mix installation will depend on the number of consumers to be served. The number of consumers determines the quantity of LPG to be stored, vaporization and air-mix plant requirements; these in turn determine the safety distances needed between the installation and adjacent buildings and fixed points of ignition. The advice from the EMSD (Gas Standards Office) should be sought. Hazard Assessments 3.3.4 Hazard assessments for gas works, gas holder stations and LPG installations form an integral part of the project evaluation and additional safety measures may need to be incorporated into the design of the installations to ensure that the risk posed to the general public is minimized. Reference should be made to the risk guidelines in Chapter 12 and procedures laid down by the Coordinating Committee on Land Use Planning and Control related to Potentially Hazardous Installations should be followed. The EMSD (Gas Standards Office) is the authority for such hazard assessments. The Land Authority shall notify the gas company concerned of any development (permanent or temporary) that is proposed within a distance of 3m either side of a high pressure (up to 35 bar) gas pipelines.
4.1 General 4.1.1 Local fixed telephone service is one of the local fixed telecommunications network services (FTNS). The local FTNS licensees are PCCW-HKT Telephone Limited (PCCW-HKT), Hutchison Global Crossing Limited (HGC), New T&T Hong Kong Limited (New T&T) and New World Telephone Limited (NWT). 4.1.2 International telephone service is one of the external telecommunications services (ETS). The FTNS licences of PCCW-HKT, HGC, New T&T and NWT have been amended to provide non-exclusive ETS. In mid- 2001, about 200 companies were awarded the Public Non-exclusive Telecommunications Services Licence to provide ETS. 4.2 Telephone Network 4.2.1 A telephone network comprises subscriber premise apparatus, subscriber lines, telephone exchanges and junction circuits. 4.2.2 Each subscriber premise apparatus is connected by a pair of subscriber lines to a local telephone exchange where switching and connection are conducted between two subscribers. 4.2.3 From the input telephone number, the switching equipment in the telephone exchange will locate the called party who may be in the same exchange or in another exchange. 4.2.4 The communication links provided between exchanges are junction circuits which are to carry inter-exchange calls. The junction circuits consist of Telephone Cables Systems and Radio Telecommunication Systems. 4.3 Telephone Exchanges 4.3.1 Generally, all telephone exchanges accommodate local exchange equipment. In some telephone exchanges, there may be other types of exchange equipment serving different functions of tandem, toll or other services. Local and tandem exchanges are more common. (a) Local Exchange Local exchange is where subscriber lines are terminated. Each local exchange serves its nearby communities. Depending on geographical situations, the density of population and business, the number of subscriber lines served by a local exchange may vary from a few hundreds to 120,000. There are about 90 local exchanges in mid-2001. (b) Tandem Exchange Tandem exchanges are employed to relay telephone calls between local exchanges. They are usually co-sited with local exchanges. 4.4 Guidelines on Provision 4.4.1 In order to meet demand for telephone service in a new town or redeveloped area on time, the FTNS operators should be advised of the scale of development at an early planning stage. The FTNS operators will investigate if telephone service can be provided from an existing local exchange, by any other methods or a new exchange is required. Telephone Exchange 4.4.2 No direct standard can be derived for land reservation as the size of site varies with a number of factors such as the number of lines and type of switching equipment. However, the following can be adopted as general guidelines:
4.4.3 In rural areas, small telephone exchanges with land reserved for minor expansion are preferred to large ones so as to preserve the rural amenity. 4.4.4 In urban areas, telephone exchanges are normally installed in specially designed multi-storey buildings. However, in exceptional cases, they can be accommodated within other types of buildings with the specific telephone exchange requirements incorporated into the building design. 4.4.5 Exchanges need to be located as near as possible to the centre of telephone service demand for efficiency and economic reasons. 4.4.6 Exchanges should be provided with easy access to main roads for external cable plant construction and equipment delivery. A corner site abutting two to three roads in rectangular shape is preferable for better cable duct laying and equipment layout. With respect to the access, parking and loading/unloading arrangements, Transport Department should be consulted at an early planning stage. 4.4.7 In general, the site should be available for the construction of the telephone exchange about 2.5 years before the completion of the first phase of major developments. This is to ensure availability of telephone service to the users of the initial phases of development. 4.4.8 Exchanges should be sited at least 200m from any power generating station, bulk in feed substation or primary substation (i.e. at 132kV or higher voltage) to avoid the risk of rise-of-earth potential and electrical interference which can be very critical to the safety of the operation personnel and to the sophisticated electronic telecommunication installations in the exchanges. 4.4.9 Telephone exchanges should be sited away from an electrified rail system, large box culvert, mullah and cable tunnel so as to avoid blockage to the multiway telephone cable lead-in ducts. The separation distance should be assessed on individual basis. FTNS operators should be consulted at an early planning stage. 4.4.10 Telephone exchanges should be located away from any dangerous goods installation such as petrol filling station and inflammable material store to avoid the risk of fire or explosion. Moreover, they should not be located near rivers or lakes to avoid flooding problems. Telephone Cables 4.4.11 Telephone cables should normally be laid in underground ducts except where prohibited by other factors such as crossing bridges, rivers and nullahs; temporary cable provision for construction sites; provision of small quantity of overhead cable in rural area due to economical reason and provision of overhead cable over privately-owned land. 4.4.12 Telephone cables should be placed as far as possible away from power generating or transformer stations except those feeding the stations. Such telephone cables may require special protection. 4.4.13 Telephone cables should be separated as far as possible from power cables. The normal separation should be at least 0.3m. For details, the "Code of Practice - Protection of Communication Network From Electrical power Distribution" issued by DG, OFTA should be referred to. 4.4.14 Telephone cables should be laid as far as possible away from electrified rail systems. In Light Rail Transit System, a minimum separating distance of 2.5 m from the nearest rail is required. For Kowloon Canton Railway System, a minimum distance of 300 m is required. 4.4.15 In principle, highway utilities reserves should be used to carry telephone cable ducts. Consultation with FTNS operators is required in an early planning stage of the highway. Radio Telecommunication Systems 4.4.16 Microwave Radio Communication Systems may be used to connect urban areas to the non-urban areas where the use of telephone cables is impracticable or not economical. 4.4.17 They are normally installed on roof top of telephone exchange buildings. However, in exceptional cases, they can also be installed in mobile containers located in the vicinity of the telephone exchange, or installed by other methods. 4.4.18 In principle, the aerial equipment needs to be situated in a location which can maintain a clear line-of-sight with the counterpart aerial equipment located at another telephone exchange building or a hill-top radio station.
5.1 General 5.1.1 The wide range of facilities within this category makes it impracticable to set out standardized land requirements. They should be considered on an individual basis. As a general principle, virgin hill top sites should be avoided as far as possible, and sharing use of existing hill top sites would be encouraged. 5.2 Guidelines on provision 5.2.1 The location and design of telecommunications structures (e.g. buildings and towers) should be determined with reference to the "Procedure for Applications to Use or Develop Hill-top and Rural Sites for Radio-telecommunications Systems (Revised Edition, June 1997)" which is issued by the Telecommunications Authority. It is available from the DG, OFTA.
6.1 General 6.1.1 Approximately two-third of the fresh water consumed in Hong Kong is obtained from Mainland China via the agreement made with the Chinese Authority. The remaining one-third are collected from gazetted water gathering grounds which occupy about one-third of the total area of the territory. 6.1.2 The principal land requirements for fresh water supply are those for storage reservoirs and water gathering grounds, water conduits, treatment works, pumping stations, service reservoirs, depots, workshops and offices. Land is also required for conduits, pumping stations, and service reservoirs for the supply of salt water for flushing. 6.1.3 Land in water gathering grounds needs not be used exclusively for water supply and there are agreed policies by which other compatible uses may be permitted. Planning of development or projects to be located inside or near the water gathering grounds should follow guidelines laid down by Water Supplies Department (WSD). These are set out in the "Working Party Report on Land Use and Development in Catchment Areas". Amongst such other uses are notably Country Parks, Special Areas or SSSIs, and other recreational areas, etc. 6.1.4 Roofs of service reservoirs in most cases provide large level surfaces. Where they are easily accessible from nearby populated areas and are not required by the WSD for operational reasons, they can be planned for open spaces, recreation grounds and other compatible uses subject to proper management and appropriate safeguards. The intention to this dual use should be agreed with the WSD before designing a service reservoir. 6.2 Locational Guidelines 6.2.1 Service Reservoirs
6.2.2 Pumping Stations
6.2.3 Treatment Works
6.2.4 Water Mains
7.1 General 7.1.1 Drainage services include the provision, operation and maintenance of foul sewerage, sewage treatment and disposal, and stormwater drainage infrastructures. Public drainage services are currently provided by the Drainage Services Department. 7.1.2 The provision of such services, whether for public or private use, shall conform with the standards and guidelines for environmental planning as set out in Chapter 9. 7.2 Foul Sewerage System 7.2.1 Sewage should be collected and conveyed in enclosed conduits which should normally be placed underground. 7.2.2 Sewers could be located under the carriageways, footpaths, cycle tracks or amenity strips. If this is not feasible, separate drainage reserves should be provided. The location and alignment of a sewer should be chosen such that, during the subsequent maintenance of the sewer, disruption to vehicular and pedestrian traffic is minimized. Where sewers are placed under carriageways, they should be located within one traffic lane as far as possible to minimize disruption to traffic during maintenance. Gravity sewerage systems should be used as far as possible. 7.3 Stormwater Drainage System 7.3.1 Stormwater may be collected and conveyed either in enclosed drains or open channels. Section 7.2.2 is also applicable to the planning and design of enclosed stormwater drains. 7.3.2 When choosing the alignment of drainage channels, account should be taken to minimize disruption to adjacent communities and minimize land resumption. Supporting facilities such as vehicular access should be provided to enable proper operation and maintenance of the drainage channels. Landscaping should be considered and incorporated to blend in with the environment. 7.3.3 Supporting drainage facilities such as channel embankments may be permitted to be used as amenities or recreational areas and access roads as waterfront promenades. 7.4 Pumping Stations and Sewage Treatment Works 7.4.1 Sewage treatment works and stormwater and sewage pumping stations should be designed to minimize noise, odour and visual problems. They should be located away from residential or other sensitive areas by providing suitable buffer zones, where possible. If this is not feasible, suitable abatement measures such as acoustic insulation, odour enclosures and landscaping should be included in the design of the facilities. 7.5 Polder Drainage and Floodwater Pumping Schemes 7.5.1 Polder drainage and floodwater pumping schemes are to render flood protection to villages in low-lying areas. The scheme entails the construction of floodwater pumping station, floodwater storage pond, and flood protective bund or wall around the villages and floodwater storage pond. 7.5.2 Floodwater storage ponds should be located at the lowest areas of the schemes. They should either be covered or properly fenced off for safety reasons. Under no circumstances should public access routes be allowed through the areas of the floodwater storage ponds. 7.6 Drainage Reserves 7.6.1 Unrestricted vehicular access to Drainage Reserves should be provided at all times. Structures of any kind should generally not be permitted unless in exceptional circumstances.
8.1 In general, utilities will not be permitted within the boundaries of an expressway, unless they are essential to its operation e.g. street lighting and emergency telephones etc.. Other utilities may be permitted in exceptional circumstances with the agreement of the Director of Highways. In the planning of new development areas, provision should be made for dedicated utility reserves on the road side pavements, such as amenity strips, pedestrian walkways and cycle tracks etc. for the laying of various utilities such as electricity and telephone cables, gas and water pipes etc. Whenever practicable, dedicated utility reserves should preferably be outside road reserves. Such arrangement would help reducing possible disruption to vehicular traffic during maintenance periods. 8.2 Adequate separation between different kinds of utility provisions shall be allowed for in the dedicated reserves. The actual width of the reserves will vary depending on individual circumstances and the types of utilities to be accommodated. Early consultation with the relevant utility companies and concerned departments at the planning stage will be necessary.
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