City gas distribution (CGD) operations involve delivering natural gas in the form of compressed natural gas (CNG) to the automobile sector and piped natural gas (PNG) to domestic, industrial and commercial customers. The gas used by these consumers within a geographical area must be below 50,000 standard cubic metres per day.
CGD operations are, however, prone to safety concerns. The Petroleum and Natural Gas Regulatory Board (PNGRB) has laid down detailed technical safety standards for city and local natural gas distribution networks. These regulations cover design, materials, fabrication, installation, inspection and testing, commissioning, operations and maintenance (O&M), modifications of downstream pipelines, distribution mains, and piping facilities from the city gate station (CGS), which is the entry point of the gas into the city, up to the final isolation valve (including the metering unit at the consumer end). The safety aspects of the O&M of CGD networks and their requirements are also covered in these regulations.
On the other hand, CNG stations (mother stations, online stations and daughter stations), which are involved in the compression, handling and transportation activities of CNG, are designed, operated and maintained as per the Gas Cylinders Rules, 2004, of the Petroleum and Explosive Safety Organisation (PESO), a statutory body under the Ministry of Commerce and Industry; the Department of Industrial Policy and Promotion; and the Oil Industry Safety Directorate (OISD) standards (OISD-STD-179). Thus, multiple bodies are involved in monitoring and controlling the safety aspects of CNG and PNG operations of the same CGD system.
For 250 bar gas consumption, the CNG station construction methodology and equipment have to be initially approved by PESO. Licences are provided to CNG stations only after a thorough inspection by PESO officials, and periodic surprise checks are conducted to ensure continual compliance with safety norms. Thus, defined sets of the safety monitoring mechanism are in place at CNG stations, but the onus of solving issues related to the mandatory testing of cylinders of CNG-driven vehicles lies with CGD operators. Given the cases of accidents, it will be prudent for the statutory bodies to design procedures and practices to ensure periodic external monitoring for identifying vehicles fitted with untested or unfit cylinders, over and above the services rendered by CGD operators.
Tagging vehicles fitted with CNG kits using radio frequency identification technology could offer a viable solution. However, for it to function effectively, strong coordination is required between state regional transport authorities, CGD operators and CNG kit suppliers, so that vehicles, along with details of their kit supplier, can be identified at any CNG refuelling station.
The approval for the downstream transmission of PNG to consumer premises lies with the PNGRB. The statute specifies that compliance levels must be checked through technical and safety audits to be conducted during the construction, commissioning and operations phase. In addition, checks must be conducted regularly either directly by the PNGRB or by an accredited third party. That said, in most cases, CGD utilities indulge in self-certification practices to meet compliance norms. There is also a case for augmenting the technical capacity of the third party in line with checks carried out by the OISD or PESO. The risk factors associated with gas on a pipeline section must be analysed, and mitigation measures carried out in a time-bound manner under the careful supervision of independent regulators like the OISD.
For PNG transmission, gas is pumped from the CGS through a steel pipeline network at a pressure of 19 bar, and is later regulated by a district regulating station (DRS) to 4 bar. This gas is carried through a polyethylene pipeline (PE) and reduced further at the consumer premises, depending on the pressure requirement. While the handling and maintenance of DRS units requires technical manpower, it has often been observed that these are left unmanned at public places like parks and roads.
Safety norms for cross-country pipelines are followed as per OISD and other international specifications. In addition, operations are monitored through the supervisory control and data acquisition (SCADA) system and other leak detection methods. As against this, CGD operations are carried out in congested areas in the absence of any standard distance between any utility pipeline and other infrastructure. Other hindrances include the fact that a limited number of CGD utilities have the facility to monitor their network using a SCADA system and many of them are not equipped with emergency shut-off devices at the sectionalising valve units on the pipeline. As per the standards, both steel and PE pipelines are to be laid 1.2 metres below ground level. However, other utility structures and pipelines like optical fibre cables and sewage pipelines are often aligned along the same route, making CGD pipelines susceptible to cuts and leakages. The technical standards laid down by the PNGRB do mandate the injection of odorant into gas for the quick detection of leakages.
Compared to OISD standards, the PNGRB’s technical standards are generic in nature. In addition, an increase in gas costs and a consequent rise in operational costs could result in allocating low capital resources for ensuring safety. To prevent this, there is a requirement for a robust independent regulator to monitor the conditions and effectiveness of the gas pipeline and its associated equipment. At the same time, PESO, the OISD, and the PNGRB or independent safety regulator must take measures to ensure certification or re-certification of critical components that are provided by vendors or are imported to the CGD sector.
To conclude, there is a need to recognise and address the risks involved in CGD operations. The diversity in the roles of separate safety agencies often creates an overlap and dilutes the stringency of audit and inspections from one to another. Since January 2014, there have been plans to rectify this by formulating a law to create a Petroleum and Natural Gas Industry Safety Board with legal powers. It is important to prioritise the formation of such a body by reconciling interministerial issues and seeking cabinet approval. Safety standards, specifications and laws, including inspections and testing for all public and private companies and vendors dealing with hydrocarbon products and equipment, should be governed by this board.
(The views in this article are those of a senior representative of the CGD segment.)