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Basic Concepts of Design & Construction of Gas Distribution Network

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1 Basic Concepts of Design & Construction of Gas Distribution Network
GSPC Gas Company Limited December, 2009 Gandhinagar

2 City Gas Distribution – An Overview

CGD is the last component of the Natural Gas value chain delivering Natural Gas to end users in town and cities to meet the demand for a cleaner, more efficient, economical and environmentally-friendly energy source. 3

Development of Pipeline Network in a pre-defined geographical spread Maintaining Different Levels of Gas Pressure to meet the Demand of various segments of gas users - Domestic, Commercial, Industrial and Automobiles. Designing high pressure and medium pressure network such that supply to any consumer is possible from either side. Design gas storage / Gas sourcing for maximum survival period Consider Health, Safety & Environment at all stages

5 Steps in the design of Gas Distribution System
Market demand estimated based on comprehensive field survey of units covering domestic, commercial, industrial and transport sectors. Demand forecast projection is carried out for years. Peak hour consumption estimated for network design. The system is to be designed based on 20-25th year projected demand at peak load in a phased manner. Reconnaissance Route Survey within the town to identify suitable routes for laying pipelines, locations for City Gate Station, District Regulating Station & CNG Station 5

6 Steps in the design of Gas Distribution System
Network design and optimization with available software Design of Mother Station and Daughter / Daughter booster station for CNG supply to automobiles National / International standards adopted for design. Project implementation done subsequently. 6

7 Battery Limits Distribution Zone Transmission Line Transmission
City Gate Station

HP Network MPB Network CITY GATE Domestic and Commercial Users DRS MPA Network CNG Mother Stations LP Network

9 CGD PRESSURE REGIMES Sr. No. Network Component Inlet from
Inlet Pressure Outlet Pressure Outlet to 1 CGS Transmission line barg 26 barg Steel Grid 2 Steel pipeline 26 – 14 barg DRS / CNG 3 DRS 4 – 1 barg MP MDPE pipeline 4 Service Regulators (SR) MP MDPE Pipeline 4 – 1 Barg 110 mBarg LP MDPE Pipeline 5 4 barg Industrial MRS & Commercial Connections 6 SR 110 – 50 mBarg Regulator of Domestic / Commercial Connections 7 Industrial MRS 4 – 1.5 barg 1.5 barg or customer specific pressure within the supply range Industrial internal pipeline 8 Online / Mother CNG Station Steel Pipeline barg 250 Barg Vehicle at 200 Barg 9 Domestic Connections 21 mBarg Meter & Gas Stove 10 Commercial Connections 110 – 75 mBarg 75 mBarg or customer specific pressure within the supply range

10 City Gas Distribution – Applicable Codes & Standards

11 European Standard 4 S. No. STANDARD NO. DESCRIPTION 1 EN 12186
Gas supply systems - Gas Pressure Regulating Stations for Transmission and Distribution. Functional Requirements 2 EN 12279 Gas pressure regulating - installations on service lines 3 EN 1776 Gas supply systems - Natural gas measuring stations - Functional requirements 4 EN 1594 Gas supply systems- Pipeline for maximum operating pressure over 16 bar- Functional requirements

S. No. STANDARD NO. DESCRIPTION 1 ASME B16.11 Forged Steel Fittings, Socket-Welding and Threaded 2 ASME B31.3 Process Piping 3 ASME B31.8 Gas Transmission and Distribution Piping Systems 4 ASME B16.5 Pipe line flanges and flanged fittings 5 ASME B16.9 Factory - Made Wrought Steel Butt welding Fittings 6 ASME- Boiler and Pressure Vessel Code Section- IX- Qualification Standard for Welding and Brazing Procedures, Welders, Brazers, and Welding and Brazing Operators 7 ASME Boiler and Pressure Vessel Code- II Part C- Specifications for welding Rods, Electrodes, and Filler Metals 8 ASME Boiler & Pressure Vessel Code Section - V, Non-destructive Examination 9 ASME Boiler and Pressure Vessel Code Section-II Materials Part A- Ferrous Material Specifications -

S. No. STANDARD NO. DESCRIPTION 1 ISO International Standard for Petroleum and natural gas industries - Induction bends, fittings and flanges for pipeline transportation systems 3 BS 6755: Part 2 Testing of Valves 4 DIN 30672, Part I Coatings of corrosion protection tapes and heat-shrinking products for pipelines for operational temperatures upto 50oC 6 DIN 30670 Polyethylene coatings for steel pipes and fittings

S. No. STANDARD NO. DESCRIPTION 1 OISD-226 Natural Gas Transmission Pipelines & City Gas Distribution Networks 2 OISD-GDN-115 Guidelines on Fire Fighting, Equipment and Appliances in Petroleum Industry 3 Fire Protection Manual- TAC Fire Engines, Trailer Pumps and Hydrant Systems 4 OISD- Standard- 141 Design and Construction requirements for cross country hydrocarbon pipelines 5 OISD-Std-118 Layouts for Oil and Gas Installations

S. No. STANDARD NO. DESCRIPTION 1 API Standard 1104 Welding of Pipelines and Related Facilities 4 API Specification 5L Specification for Line pipe 5 API Spec. 6D Specification for Pipeline Valves ( Gate, Plug, Ball and Check Valves) 7 API Standard 1102 Specification for steel pipeline crossing & highways.

S. No. STANDARD NO. DESCRIPTION 1 AGA Purging Principles and Practices 2 IGE/TD/1 Steel Pipelines for High Pressure Gas Transmission 5 AGA: Report No. 7 Measurement of Gas by Turbine Meters 6 AGA Report No.3 Orifice metering of Natural Gas and other related Hydrocarbon fluids 7 AGA-Report No 8 Compressibility factors of Natural Gas and other related Hydrocarbon gases

17 City Gas Distribution – System Components

18 CGD - Infrastructure Major Constituents of CGD are; City Gate station
Pipeline Network Steel Pipelines Poly Ethylene Pipelines GI / Cu Pipes Regulating Stations District Regulating Stations Service Regulators Domestic / Commercial / Industrial Regulators Metering Stations / Metering & Regulating Stations CNG Stations

CGS is the location of Custody Transfer from Transmission Company to Distribution Company.

Inlet & Outlet isolation valves Knock Out Drum (KOD), If required Filter Metering Unit (Turbine / Orifice / Ultrasonic) Gas Chromatograph (GC), If required Pre-heater (if required) Pressure reduction skid comprising Active & monitor Regulators Stream discrimination arrangement Slam shut valve for over & under pressure protection Creep relief valves. Odorising Unit

21 STEEL PIPELINE The Steel Grid pipeline sizes is 12”NB & 8”NB whereas, spur lines shall be of 6”NB & 4”NB. Steel pipelines used in the distribution system is fully coated. The coating is extruded polyethylene, with each weld joint coated with either heat shrink sleeves or field applied tape. Prior to the pipeline being put into service, the distribution pipeline to be non-destructively tested by two methods. Firstly, welds would be radio graphed and, secondly, the completed pipeline extension would be hydro-statically tested at a higher pressure than its operating pressure. After hydrostatic testing, the pipeline to be dried, purged and filled with natural gas. The testing and commissioning procedures will be detailed during the detailed design phase of the project.

22 STEEL PIPELINE To protect the pipeline from corrosion, a cathodic protection (CP) system of impressed current is proposed. During the detailed design phase, the CP capability of the existing transmission system will be investigated to establish if it has the capacity to provide CP to the extension. If it is found that the existing system does not have the capacity, additional CP facilities will be designed. The steel grid is installed at a minimum depth of 1.0 meter cover, and in accordance with Indian requirements.

23 MDPE PIPELINE The distribution pipe is with Standard Dimension Ratio (SDR 9) for 20 mm, (SDR) 11 from 32 mm up to 63 mm & (SDR) 17.6 for above 63 mm. The term SDR is defined as the normal outside diameter (DN) divided by the minimum wall thickness. It is standard practice in India to have a minimum 1.0 meter cover. This additional depth in a densely populated area would be recommended. All MDPE pipe back filled with sand around it to protect the plastic material.


25 Medium Density PolyEthylene (MDPE) Pipes
Tech Spec: IS 14885:2001 & ISO 4437 Material Grade & Color: Internationally approved resins of PE 100 grade of Orange color Minimum Required Strength (MRS) of PE 100 grade pipe: 10 MPa Pressure Class: SDR 9 (dia 20 mm), SDR 11 (dia 32 & 63 mm) and SDR 17.6 (dia 90, 110, 125 and 160 mm). Operating pressure: 4 bar (g). Operating temperature range: C to C.

26 Advantages of PE pipes High performance (Globally proven leak free system) More Flexibility, coil ability, ductility, High elasticity Low density (low weight, high strength to weight ratio) High resistance to corrosion Low heat conductivity (small thermal loss) Smooth surfaces (low pressure losses due to low pipe friction) Easy to transport, handle and lay Longer life

27 Advantages of PE pipes Easier and speedier joining techniques to ensure leak tight joints by employing electro fusion techniques Higher productivity, i.e., reduction in installation time (15 minutes in case of PE against 4 hours in case of steel), thereby lesser inconvenience to public Reduced number of joints, hence safer and leak free system Less time is consumed to repair PE damages as compared to steel damages Good squeeze off properties

28 Advantages of PE pipes Longer design life of PE pipes (50 years) as compared to steel pipeline (30 years) Avoidance of NDT techniques in building premises, which is very critical Size of trench is less in case of laying of PE pipe as compared to steel

29 MDPE Fittings Tech Spec: ISO 8085-3 or EN 1555-3
Material Grade: PE 100 Terminal pin size: 4 or 4.7 mm Voltage: 39 – 40 Volts. Color: Black.

30 PE Stop Off Valves (Typical)
Standard: ASME B 16.40, EN Pressure Class: SDR 11. Design Pressure: 5.5 bar (g). Design Temperature: 45 0 C. Operating Temperature: 10 0 C to 45 0 C End Connections: PE Material (Spigot Type) Stem Extension: Integral stem extension required (Minimum 690 mm from the Top of Pipe) Valve Design: One piece construction. Ball position Indicator: Open / Close limits required.

31 Crimping Fitting (Typical specification)
Used to connect u/g PE pipes with a/g GI pipes Operating Pressure: up to 4 bar (g) Operating Temperature: 40 0 C Hydrostatic Test Pressure: Minimum hold Pressure of 10 bar (g), for 1 hour duration Pneumatic Test Pressure: Minimum pressure of 6 bar (g), for 1 hour duration Pull out Test: Shall not fracture within the jointed assembly Shall withstand the Pneumatic pressure leak test Shall not leak

32 District Regulating Stations

33 District Regulating Station

34 District Regulating Station

35 Service Regulators

36 Typical requirements of Pressure Regulators used for domestic and small I&C customers
Maximum Inlet Pressure: Maximum 4 bar (g) Nominal Outlet Pressure: 100 mbar (g) Flow capacities: 50, 150, 200, 250 scmh End connections: Threaded (& Tapered) as per BS 21 Operating ambient temperature: up to 45 0C Lockup: Maximum pressure, under no-flow condition, up to 125 mbar (g) Creep relief valve: To protect against downstream over pressure at low flows or in the event of valve seat malfunction, preset to 140 mbar (g) Over Pressure Shut Off (OPSO): Device to protect against downstream over pressure, preset to 160 mbar (g) Under Pressure Shut Off (UPSO): Device to protect against downstream under pressure with a pressure setting range 40 mbar (g) to 65 mbar (g)

37 Regulator Selection Information required to select a regulator:
Maximum and Minimum inlet pressure Required outlet pressure Maximum flow rate Tolerance on outlet pressure Size of pipework Type of gas Safety features required Size of orifice OPSS, UPSS & Relief settings Installation indoors of outdoors Orientation of regulator


39 Gas Meters The most common types of meters used are: Diaphragm
Rotary Positive Displacement (RPD) Turbine

40 Diaphragm Gas Meters (Domestic)
Tech Spec: EN 1359 Capacity: 2.5 m3/hr Rangeability or TD ratio: 1:150 or better Nominal Working Pressure: 21 mbar (g) End Connections: ¾”, as per BS 746 (Male) Center to Center distance: 110 mm between inlet and outlet connections

41 Diaphragm Gas Meters (Commercial)
Tech Spec: EN 1359 Capacity: 10, 25, 40, 65 scmh Rangeability or Turn Down ratio (ratio of Qmax and Qmin): 1:150 or better Nominal working Pressure: 100 mbar (g) Pressure rating : Suitable to withstand maximum working pressure of 200 mbar (g)

42 Rotary Positive Displacement (RPD) meters
Tech Spec: EN 12480 Volumetric meter Appropriate for medium size load Typical Turndown 35:1 to 50:1 Accuracy ±1% Large measuring range Not sensitive against disturbances Not sensitive against fast changes in flow rate Needs lubrication

43 Rotary Positive Displacement (RPD) meters
Magnetic coupling: A magnetic coupling is used to transmit the movement of the pistons (impellers) to the totaliser

44 Rotary Positive Displacement (RPD) meters
Advantages Disadvantages Good flow turndown Filtration essential (50 microns or finer) Tolerance to installation effects and load behaviour Requires lubrication Accuracy ±1% Physical size at large capacities Much smaller than a diaphragm meter Can create pressure fluctuations on on/off loads Very long life Can cut off gas supply when it fails Expensive

45 Industrial Metering Station (IMS)
IMS are used to measure gas supplied to Industrial consumers Main component in IMS is filter, Isolation Valves, RPD Meters with EVC & Modem, Regulators (If low pressure requirement) and Non return Valve Inlet pressure range – 1.5 Barg to 4 Barg Outlet pressure – As required by customer

46 MRS components Inlet & Outlet isolation valves Filter
Pressure regulator with a built in slam – shut device Relief valve Strainer Flow Meter (RPD, Turbine, etc.)

47 GI ERW Pipes Tech Spec: IS 1239 (Part 1)
Types used: Medium Class and Heavy Class Material: IS 1387 Pipes shall be screwed with Taper threads Threads: Tapered and conforming to BS 21 Galvanizing: IS 4736 Coating requirements: Mass of coating is 400 gms / m2 Test Pressure: 5 MPa Powder Coating: Powder Material: Pure Polyester Application: Electrostatic spraying (40 – 90 KV, Manual / Automatic)

48 GI Fittings (Malleable Cast Iron)
Tech Spec: IS 1879 Material: IS 2108 Grade BM 290 Dimensions: IS 1879 Threads: IS 554 All Internal & External Threads shall be tapered Chamfer shall have included angle of 900 +/- 50 for Internal threads & 700 +/- 100 for external threads Galvanizing: IS 4759 Coating requirements: Mass of coating is 700 gms / m2.

49 Forged Fittings (Wrought Steel Iron)
Tech Spec: IS 1239 Part 2 Material: IS 1387 Dimensions & Tolerances: IS 1239 Part 2 Threads: IS 554 All Internal & External Threads shall be tapered Chamfer shall have included angle of 900 +/- 50 for Internal threads & /- 100 for external threads Galvanizing: IS 4759 Coating requirements: Mass of coating is 700 gms / m2.

50 Brass Valves (Meter Control Valves, Riser Isolation Valves & Appliance Valves)
Tech Spec: EN 331 Pipe Nominal Diameter :- ¼” to 2” NB. Operating Pressure: 4 bar (g). Operating Temperature: 10 – 60 0 C. Material: Nickel Plated Forged Brass. Pattern: Full Bore, Quarter Turn Ball Valve. Handle: Suitable Metallic Handle, Lever / Knob / Cap Type with yellow coating (Powder / Plastic) on Surface marked as “GAS” End connection: Screwed, As per BS EN , Tapered Threaded, Female

51 Meter Regulator Gas flow rate: 2.5 m3/h
Nominal Inlet Pressure: 100 mbar (g) Maximum Inlet Pressure: 160 mbar (g) Nominal Outlet pressure: 21 mbar (g) Lock-up pressure: Shall not exceed 30 mbar (g) Low pressure Cut-Off: at inlet pressure of 11.5 mbar to 15 mbar (g). Re-pressurization safety device is fitted which prevents the regulator from re- opening when the inlet pressure is restored unless there is a downstream backpressure, i.e., all connected appliances have been turned off. End connections: Right angled inlet and outlet connections of ¾”x ¾” BSPT (Female)

52 Rubber Hose (flexible and steel wire braided)
Used to connect the appliance, inside the house of domestic customer Tech Spec: Type IV of IS 9573 Size: 8 mm NB Material: It consists of Lining: Synthetic rubber like Nitrile Butadiene Rubber (NBR) or Chloroprene Rubber (CR) Reinforcement: Wire reinforced in braided form in between the lining and the cover Cover: Consolidated by wrapping, and uniformly vulcanized to give good adhesion

53 Rubber Hose (flexible and steel wire braided)
Mechanical Properties: Tensile strength: Minimum 10 MPa for lining and cover Elongation at break: Minimum 200% for lining and 250% for cover Salient features: Strong (Steel wire reinforced) hence rats can't bite through steel wire Flame resistant Abrasion, ozone and weather resistant, hence no cracks Low temperature flexibility Minimum burst pressure of 0.5 MPa Long life (5 years) Grip strength (to nozzle of appliance)

54 City Gas Distribution – Network Design

55 System Basics System of units
The International System of Units (SI), also known as the "Metric System" to be used. The International Gas Union (IGU) has also recommended to generalize the use of the SI system in all matters relating to Gas and Gas facilities. The SI system shall be in compliance with ISO The SI system shall be of general use with exception to the following: Gas Volumes and Flow, Pressure, Temperature, Heating Value Pipeline and Piping Nominal Diameters shall be expressed under either one or both systems where "Common Practice" of Pipeline and Piping Engineers so suggests;

56 System Basics Data relating to equipment shall use that system of unit that is most common in the relations with suppliers. Where advisable for good understanding, the corresponding value in the other System of Units shall be mentioned between brackets. Results of technical calculation and related figures issued from specific software shall remain expressed in that system of units that is used by the relevant software.

57 Steel Pipelines Steel mains High-Pressure Mains
Notwithstanding the major advantages of polyethylene (PE), steel pipelines remain necessary as follows; High-Pressure Mains Location class: the design of High pressure mains shall consider requirements as for Location Class 4 (ASME 31.8) to allow timelessness should the environment change in the future. Wall thickness: according to ASME B31.8 – Section with Design factor of 0.4. In addition, wall thickness shall, in no way, be lower than the values below in function of Nominal Diameter (ND)

58 Steel Pipelines 4 in. and below - 3.9 mm 6 in. - 4.5 mm 8 in. - 5.0 mm
GSPC Gas is using 6.4 MM Wall thickness. Steel Grade: The Design Concept considers API Grade X 52 Steel quality to offer maximum flexibility for line pipes procurement. Bend Radius: to allow pigging under special circumstances

59 Steel Pipelines Steel Pipes API 5 L - Line Pipes
ASTM A Seamless Pipes ASTM A Seamless & Welded Pipes for low temperature services Location Class Location Class I - 10 or fewer buildings in 1 mile section Location Class I I - 10 – 46 buildings in 1 mile section Location Class III - 46 or more buildings in 1 mile section Location Class IV - Areas where multi story building & heavy traffic plus other underground utilities Steel Pipe Design Formulae P = (2 St/D) * FET – As per ASME B 31.8, (a) t = PD / 20fs

60 Steel Pipelines Above Ground Mains
Polyethylene being forbidden for above ground crossings, if any, steel mains sections are needed at the crossing with PE/steel transition fitting to be buried with the adjacent PE mains.

61 Steel Pipelines Process Design Wey-mouth Formulae
Q = * (d) * {(p12-p22)1/2 / (S * L)1/2 } Velocity V = Q / A Velocity for filtered gas to be 40 m/s & unfiltered gas to be 20 m/s maximum.

62 Example P 1 = 15 Barg, P2 = 10 Barg (Min.) Q = 2,00,000 SCMD
L = 32,000 m 1 2

63 Example Q = 2,00,000 SCMD i.e. 9, SCMH Using Wey Mouth Formulae: Q = * (d) * {(p12-p22)1/2 / (S * L)1/2} = x (d) * {( )1/2/(S* L)1/2} d = mm : Calculated Diameter. We have to select diameter from the available range e.g mm from API 5 L Now, P1V1 = P2V2 1.013 * 9, = ( ) * V2 V2 = M3 / Hr = M3 / Sec. Now, for Velocity, Q = A * v = (3.14/4) * (200.1 * 10-3)2 * v V = 7.94 m/s Now, for Wall Thickness, t = (P*D) / 20fs t= ( * 219.1) / (20 * 0.29 * 241) t = mm

64 Example P 1 = 26 Barg, P2 = 10 Barg (Min.) Q = 1 Q = 9250
L = m L = 20000 Q = 4000 L = 7000 1 2 3 21

65 Polyethylene Pipelines
MRS (Minimum Required Strength) The MRS value represents the long-term circumferential stress in the pipe under which the break may occur after 50 years at the earliest. Stress = MRS / C, where C is overall service coefficient The minimum value of C for the material to be used for Gas application is 2. MAOP (Max. allowable Operating Pressure) MAOP = (20 * MRS) / [C * (SDR-1)]. Standard Dimension Ratio SDR = Dn / En SDR used in GSPC Gas is SDR 9, SDR 11 & SDR 17.6 Standard followed by GSPC Gas IS 14885: 2001

66 Polyethylene Pipelines
Base resin The PE resins of “Third Generation” (PE 100 or MRS 10) in full compliance with detailed specification is being used. First Generation is PE 63, second PE 80 & Third generation is PE 100. Wall thickness The MDPE network designed and qualified for a MOP of 4 bar. The “Network analysis” and resulting structure and behaviors are based on such design. PE line pipes wall thickness shall be in accordance with the following SDR Gas mains (ND ≥ 90 mm): SDR 17.6 Gas mains and Service lines (ND ≤ 90 mm): SDR 11. Service lines (ND = 20 mm): SDR 9

67 Polyethylene Pipelines
Different Material used for PE Pipes The following materials have been approved to date: Solvay Eltex TUB 121(Black) or Eltex TUB 125(Orange) PE 100 Borealis HE 2490 PE 100 Fina Finathene XS 10 B PE 100 Dow BG PE 100 Elenac Hostalen CRP 100 PE 100 Codes: Manufacturer Commercial Brand Name Code(*) SOLVAY ELTEX TUB 121/125 E3 BOREALIS HE N3 FINA FINATHENE XS 10 B F3 DOW BG D3 ELENAC HOSTALEN CRP H7

68 Polyethylene Pipelines
Process Design Wey-mouth Formulae Q = * (d)2.664 * {(p12-p22)0.544 / (S * L)1/2} Velocity V = Q / A Velocity for filtered gas to be 40 m/s & unfiltered gas to be 20 m/s. Being a complex network, required specialized tools for Planning & Designing the network. GSPC Gas use SynerGEE software for designing the PE Network.

69 PNG Domestic & Commercial Connection
Process Design Polyflow Formulae Q = * 10-3 * (d)2.623 * {(h/L)0.541} Peak Gas flow is 0.5 SCMH for one house Being a standard PNG Connection, we have standardize the design of PNG Network as follows; ½” GI pipes up to G + 4 apartments OR 5 connections in case of raw house. 1” GI Pipe above 5th Floor apartment OR above five connections in raw house.


71 PNG Domestic & Commercial Connection
Route Selection for GI / Copper Pipe Installation Route selection for GI pipe installation shall be carried out as per the guideline given below; Pipe shall not be installed on un-plastered wall or in the house under construction. Pipe shall not be installed in an unventilated void space. Route shall be selected that maximum length of the pipeline shall be installed outside. Route of the pipeline shall be planned for the shortest possible length. The gas pipeline shall be away (minimum distance of 200mm) from the electrical line. There shall be minimum change of directions and minimum no of threaded joints. Maximum two Point in the kitchen for gas stove only. Compound gate or doors and windows inside the house shall not hit the Gas pipeline. Copper installation should be a minimum 300mm away from heat source and Electrical installations. If it is not possible for copper installation then suitable protection should be given. If the copper pipe installation is carried out inside cupboards, there should be a provision for adequate ventilation like louvers/holes in cupboard doors.

72 PNG Domestic & Commercial Connection
Positioning of Valves, Regulator & Meter Riser Isolation Valve: For apartments, one riser isolation valve shall be provided at a height of 2 meter From the ground and individual meter control valve shall be installed for each connection. The riser isolation valve shall be installed at a convenient height so that it is easy to operate the valve in emergency. Meter Regulator: Regulator shall be installed in such a way that it reduces the length of H.P. Line (Max. pressure 0.1 Bar) to minimum possible. Wherever possible meter Regulator shall always be installed outside residence and at a convenient height.

73 PNG Domestic & Commercial Connection
Gas Meter: Gas Meter shall be installed in such a way that it shall be protected from direct rain or waterfall on the meter. Location of the Gas meter shall be decided during the route selection. Meter shall be installed at convenient height so that it is easy for the meter reader to take correct readings. The meter shall never be positioned very near to Electric Line. A minimum distance of 200 mm shall be maintained. Appliance Valve: The position of the appliance valve shall be convenient to operate and it shall keep the rubber tube at a safe distance from the heat source. The orientation and distance from cooking platform/ground shall be maintained in such a way that the Bending Radius of the Rubber Tube shall be more than 100mm. Appliance valve shall be installed in ventilated space and the lever of appliance valve shall not foul with the wall during the on-off operation.

74 Clamping

75 GI Pipe cutting & Threading
After site and route clearance, the measurements for pipe cutting shall be taken and pipes shall be cut accurately as per the required lengths. If the length of pipes is not correct, the threaded joints come under heavy stresses, which may ultimately cause gas leakage. Installed piping threaded connections / joints shall be tightened in such a way that all the joints shall be free from heavy stresses and misalignments due to incorrect pipe length. The condition of thread die and pipe vice jaws shall be checked regularly and shall be free from defects. Cutting fluids (oils) shall be used while thread cutting. Threaded pipes shall be handled carefully so that the threaded oily portion shall be free from dust, mud, water and any damage due to impact of any object. Cutting burrs on the pipe shall be removed from the edges. The edges shall be straight and free from Knife-edge formation.

76 G.I. Pipe Installation & Clamping
Teflon tapes shall be wrapped on threaded portion of the pipe with minimum three overlaps. The Teflon tap should be of approved make and gauge. The no of clamps shall be adequate. The pipeline portion containing the Regulator and Meter, either horizontal or vertical, shall have clamps on both side of the regulator and meter. Clamps shall be fitted in such a way that they do not create misalignment of pipes. The clamp shall be installed by drilling 6 mm hole in plastered wall and screwed using rowel plug. Distance between two clamps shall not be more than 2 meter; the gap between riser and wall shall be minimum 25 mm. Clamps shall be installed in a straight line and shall be parallel to each other. The clamps shall be fixed properly on the walls and should grip pipe in position. For wall crossing, drill the hole with the help of electrical drilling machine in such a way that plaster and tiles shall not be damaged. It shall be ensured that there is no concealed wiring or any other fitting on the opposite side of the wall for a particular location of drilling.

77 G.I. Pipe Installation & Clamping
Self-adhesive anticorrosive tape shall be wrapped on the pipe with 50% overlap. Casing sleeve shall be installed in wall for wall crossing. Alignment of the pipeline shall be maintained. Whenever compound gate, house door or window hits the G.I. pipe protection clamp shall be installed to protect the pipe. Concealed piping shall not be done. All the pipes shall run on walls with clamps. Pipe should not be overhung and shall not be installed without pipe clamp. Wherever powder coating is peeled off during fitting and tightening of the pipe, touch up shall be done after the installation is completed by two coats of approved paint. Prior to installation all pipes and fittings shall be checked internally to ensure that they are free from any obstruction. PE to GI (transition fitting) joint shall be provided above ground.

78 Installation of Valves, Regulator & Meter
Union and testing T shall be installed before riser isolation valve. Meter control valves, Meter regulator and Gas meter shall be protected from the over tightening of the thread. Valves, Meter regulator and Gas meter shall be installed with the clamps on both sides. As far as possible hex nipple shall not be used for connecting. Both side threaded 3” to 8” long pipe nipple shall be used. Gas meter, regulator and installed piping shall be aligned properly. Flow direction of the gas meter shall be checked before installation. Flat rubber washer shall be checked and ensure at inlet and out let of the adaptor joint to the meter. Pipe nipple shall be installed between elbow and regulator to avoid direct load of line or riser on regulator and a clamp must be provided on the pipe nipple.

79 Testing of Installed Piping Connection
Before carrying out the pneumatic test of the whole installation; testing assembly, air foot pump with pressure gauge / manometer shall be checked its calibration and proper functioning. Before pneumatic testing of the installed connection spacing between two clamps, tightening of the clamps thread joints, alignments of the whole piping shall be checked. Valve shall be kept in open position and the appliance valve shall be kept in close position. Calibrated pressure gauge shall be used having the range of 0 – 1 Bar. Position of the pointer of the pressure gauge shall not be marked with the marker pen on the glass. It should be recorded in the test records. Pneumatic testing pressure shall be kept 1.5 times of the working pressure and should be maintained for 30 minutes. After pressurization of the whole piping section shall be checked for the leakage with the help of soap solution. During the testing, air should reach up to the appliance valve. After completion of testing, pressurized air shall be released from appliance valve only.

80 Conversion of Burner All the appliance valve and riser isolation valve shall be kept in closed position. Ensure that meter and regulator adaptor shall be leak proof. Open the burner knob and remove the plug from the hot plate. Clean the simmer hole. Make the simmer hole of 0.6 mm with the help of simmer drill. At the time of drilling the hole, ensure that it should not be inclined. Remove the dust from plug. After greasing, plug and knob should be properly positioned at their original position. Remove the burner from hot plate and clean it. Open the existing jet (LPG) and replace it by 125 no jet if it is big burner or 110 no jet if it is small burner. Place the burner on its original position and connect the nozzle with appliance valve using flexible and braided rubber hose. The length of rubber hose shall not exceed 1.5 mtr. Both the ends of the rubber hose shall be clamped by metallic clamps on the nozzle. Check all the joints with soap solution and ensure that the flame color should be blue.

81 All the Best

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