Mon. Jan 17th, 2022

City gas distribution

Transporting future fuel


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Schedule 1E of T4S discuss the Operating & Maintenance Procedure affecting the safety of gas transmission & distribution facilities.

The entity operating a CGD network shall have an effective Health, Safety and Environment Management System (HSE Management System) and Management of Change System in place to ensure overall safety during operation and emergencies.

The HSE Management System shall cover the following key elements.

  1. HSE Policy Statement
  2. Organizational objectives to ensure implementation of the policy
  3. Set of detailed processes supporting each activities of the HSE management system
  4. Implementation of control and monitoring activities
  5. Periodic monitoring, review and reporting of performance
  6. Audit of internal and external activities

Following processes shall be prepared as part of HSE Management System:

  1. Emergency Management System to safely handle emergencies with minimal risk.
  2. Disaster Management Plan encompassing offsite and onsite emergency response plans and mutual aid system
  3. Hazard Identification Processes such as HAZOP
  4. Risk Analysis and Risk Assessment Process such as QRA
  5. Safety and Technical Competency System.
  6. An Operational Health and Safety Legal applicability Matrix as well as Operational Health and Safety (OH&S) Legal Compliance matrix.
  7. An Environmental Legislative Register (ELR) to provide the user a register of practical implementation in terms of day-to-day activities with which the operation has to comply. Of particular relevance are the details of consents / permits / authorization or licenses required for an activity and from whom and how it is obtained.
  8. Additional practices like carrying out periodic Work Place Inspection of all Critical Activities by senior management team, implementation of Behavior Based Safety Programs and implementation of Safety Intervention System should be considered to improve the safety culture of the organization.
  9. For Safe Control of Operations (SCO), a systematic Management of Change process shall be developed to identify and consider the impact of changes to pipeline systems and their integrity. Management of Change should address technical, physical, procedural and organizational changes of the system, whether permanent or temporary.

GIS based asset management system: The entity operating a CGD network shall put in place a GIS (Geographical Information System) based system with the intention of capturing the entire underground gas network and customer database. This system shall include details of the entire pipe network. All the pipelines laid shall be identified in GIS through georeferenced co-ordinates. All failures in the pipelines shall be mapped in GIS for investigations.

The system shall include the following features:-

  1. Entire network view ability on one platform to manage the huge database
  2. All network extensions and expansions to be mapped and updated in GIS with geo-referenced co-ordinates for better identification.
  3. Immediate availability of the new constructed pipeline locations and customer base information to the user groups allowing related analysis, planning and future projections of new possibilities of pipelines, customers, gas volumes and revenue including jobs to be undertaken by third party.

GIS shall be used during the entire life cycle of the asset.

Essential Features of the Operating and Maintenance plan: Operating and Maintenance procedure should also address the following;

  1. Preventive maintenance plan and procedures required in accordance with recommendations of Original Equipment Manufacturer(s) (OEMs).
  2. A well-designed system of periodic inspection for all facilities.
  3. Calibration plan for meters, gauges and other instruments affecting quality and safety of system.
  4. Plan for functional testing of pressure regulation and control equipment (Active / Monitor Regulator, Slam Shut Valve, Pressure Relief Valves, control valves etc.)
  5. Isolation scheme (complete with drawings showing the orientation of the facilities, location of major services, power switches, entry and emergency exits, fire assembly points etc.). It should cover main components, including their identification number.
  6. Limits of operating parameters (pressure, temperature, flow, levels etc.)
  7. An Alarm Management System to monitor, analyze, segregate and appropriate action.
  8. “Work Permit” procedures to be followed by maintenance personnel for protection of property from damage and fire etc.
  9. Procedures to log operation and maintenance activities.
  10. Personal Protective Equipment (PPE) to be used by all operating personnel.
  11. Do’s and Don’ts and safety precautions during operation and maintenance.

Provisions of periodic inspections along the route of steel pipelines or mains shall include all sections of pipelines and mains irrespective of operating hoop stress.

Essential Features of the Emergency Plan

  1. Entities operating CGD Networks shall provide for an Emergency Control Room, manned round the clock and equipped with effective communication system and emergency vehicles fitted with communication facilities, first aid equipment, fire extinguishers, gas detectors, repair kits and tools, maps, plans, material safety data sheets etc. at its disposal.
  2. The CGD entity shall put in place an Emergency Response Plan, a Disaster Management Plan and a Pandemic Plan. While preparing these plans the entity shall take into confidence the various local authorities (i.e. The Fire authorities, Police authorities, Health authorities, local administration, Disaster Management authorities, Mutual aid, Factory inspectorate etc.) and clearly elaborate on their role in case of an incident.

Accident / emergency reporting procedures

The entity shall put in place a documented in house accident reporting procedure and its response plan for all kind of accidents/emergencies such as (i) near miss accidents, (ii) accidents without loss of production, supply or human life, (iii) accidents with loss of production, supply or human life, (iv) fire (v) explosion or other emergencies leading to disaster effecting
outside public. The level of reporting shall also be mentioned in the procedure. The Board shall be informed in respect of the accidents or emergencies under category (iii), (iv) and (v) above with remedial measures for avoiding recurrence in the format as asked by the respective Board.

Notwithstanding anything contained herein under, in case any incident escalates and gets media attention or gets published in newspapers, the entity shall proactively inform the Board of the same immediately with preliminary investigation report. Further, detailed report of the findings shall be furnished to the Board within a period of thirty days.

Written Emergency procedures

Special attention should also be given to following while preparing Emergency procedures:

  1. Do’s and Don’ts during and emergency and other safety instructions.
  2. Telephone numbers of emergency response team members, emergency services, mutual aid industries, district authorities, law enforcing agencies, contractors / vendors, fire services, district civic authorities, etc.
  3. Actions to be taken during an emergency including warning / cordoning off of affected area and informing the civil authorities and / or other utility companies affected by any emergency.


Training shall be imparted to the CGD Network operating and maintenance staff at the time of induction followed by periodic refresher courses. The training program should cover following:

  1. Hazardous characteristics of Gas.
  2. Familiarization with commissioning, operation and maintenance procedures.
  3. Hands on experience on operation of emergency and manual shut down systems.
  4. Effective isolation of any gas leak.
  5. Safety regulations and accident prevention
  6. Firefighting equipment operation and its upkeep.
  7. First Aid and Housekeeping

The training process should be subjected to periodic internal audits to ensure effective implementation and improvement. Training shall include mock safety drills, at least twice a year.
Training program shall also envision imparting training to employees and contractors of other utility companies sharing the same corridor to make them aware about hazards associated with leak / damages.


Entity owning or operating CGD networks should have designated personnel to liaison with other existing utility companies, district
local administration and gas supplying companies. A utility co-ordination team consisting of representatives from all other utility companies and civil authorities can substantially improve safety records.

Educational Programs

Entities operating CGD Networks shall undertake a comprehensive public awareness program for consumers and general public. The educational material shall be prepared in local, Hindi and English language. Local audio visual media available should be used for such educational programmes.

Pipeline Failure Investigation

Besides reporting and recording of all instances of asset related failures, damage to the environment and third party property shall also be recorded.
Failure investigating team shall comprise personnel trained in failure investigations. The data from all failure occurrences should be analyzed for trends so that proper initiatives including training could be taken to minimize failures.

Prevention of Accidental Ignition

Site Specific Risk Assessment should be carried out before commencing any repair activities. The outcome of such risk assessment should be documented and considered while preparing safety plan for the repair work. No hot work should be undertaken without proper work permit issued by authorized personnel.

Blasting Effects

No blasting should be carried out within city limits and near any third party structures or facilities. In any case blasting shall only be used after proper authorization from civil authorities even if it is safe to carryout such operations.


Markers: Markers shall be positioned along entire network at a maximum spacing of 100 meters in urban area and 200 meters within industrial parks for steel mains. Additional warning signs or markers shall be installed to indicate the presence of a pipeline at road, highway, railroad, stream,
canal, nala crossings and other locations where there is a possibility of damage or interference. A marker shall be marked in bold and legible local language and Hindi / English with at least the following:
• Name of CGD Network Operating Company
• Contact Telephone Number to report emergency.
• Location Area Code
• Warning – “High Pressure Gas Line, Dial before Digging” etc.
Markers may not be installed for service pipeline within consumer premises, however, the Operating Company shall maintain such service pipeline routing drawings for easy reference. The operating company shall provide minimum safety information to the consumer/customer before starting the gas supply.
It shall be mandatory for the group housing societies/cluster of houses etc. which are providing the inbuilt facilities for the natural gas connectivity to each and every dwelling unit in such buildings to have the line diagrams of the connection piping fixed at the main entrance of such premises.


Patrolling schedule shall be such that entire primary network is inspected at least once in three (3) month and secondary network is inspected at least once every month to observe surface conditions, construction activity, encroachments, soil wash outs and any other factors that may affect the safety and operation of the network.

Leakage Surveys

Operating company must have an effective method to identify and locate leakages in the system. Any one or combination of methods described in ASME B 31.8, Appendix M can be adopted based on their effectiveness for the specific areas. Highly congested areas shall be surveyed using gas detectors at least once in three months. Other less congested areas shall be surveyed at least once a year. Leakage Surveys using gas detectors shall
be done in accordance with the requirements of ASME B 31.8. Gas detectors, duly calibrated, shall be available at all times in ready use conditions for emergency surveys and use.

Requirements for Abandoning, Disconnecting, and Reinstalling Distribution Facilities

Abandoning, disconnecting, or reinstalling distribution facilities shall be as per ASME B31.8. Any activity associated with abandoning, disconnecting, or reinstalling of distribution facilities shall require Work Permit issued by the authorized person.

Plastic Pipe Maintenance

The following safety precautions shall be ensured during emergency repairs or breakdown maintenance of pipelines:
• All naked flames, sources of ignition and mobile phones shall not be allowed in the immediate work area.
• Gas level should be monitored during the repair work with gas detectors. The repair shall not be carried out in atmosphere which contains natural gas.
• Adequate fire extinguishing equipment shall be available during such repair.

Squeezing-off and reopening of Thermoplastic Pipe or Tubing for Pressure Control

Location where Squeezing and reopening is done once shall be marked appropriately to identify that the pipe has been squeezed and reopened.
Squeezing of reopened pipe at the same location is not permitted. Minimum distance between consecutive squeeze-off locations shall not be less than five (5) meters.

Repair of Plastic Pipe or Tubing

Damaged or defective plastic pipe shall be cut and replaced with new pipe.
Repair of damaged plastic pipe by using repair patches is not permitted.
Only repair method allowed is use of full encirclement split sleeves which shall be in accordance with ASME B 31.8.


Flexible steel braided hose used to connect consumer appliances should be inspected at least once every year for leakage, kinking, corrosion, abrasion or any other signs of wear and damage. Any hose worn out or damaged must be removed from service and replaced.


Steel pipelines and mains used in CGD Network shall not be used for duel service. Conversion of existing steel pipelines, previously used for service other than natural gas, for use in CGD Networks is not permitted.

Besides the details of leak records as covered under ASME B31.8 Para 851.6 and 852.6, the CGD Network Company shall also maintain following records/ documents:

  1. Design specification
  2. Alignment sheets for primary network of steel pipeline and associated pipe book and other installation and test records
  3. Surveillance inspection and maintenance records
  4. Material certification including dimension, metallurgy, destructive and non-destructive testing records, performance and functional test
  5. Welding records including PQR, WPS and welder qualification records
  6. Commissioning reports
  7. Non-conformance / deviation records
  8. Calibration records of Inspection,
  9. Measuring, Metering and Test equipment
  10. Audit compliance reports
  11. Statutory clearances
  12. Approved drawings /documents
  13. HAZOP / Risk Assessment reports and compliance to recommendations of such reports
  14. All operation and maintenance manuals

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