Piped gas: Last-mile concerns

It is a cooking gas revolution in the making. Quietly spreading its pipeline network across Bengaluru, the Gas Authority of India (GAIL) is edging out the ubiquitous LPG cylinder from the kitchen. In at least five city areas, Bengalureans have made that dramatic shift to Piped Natural Gas (PNG). Forever!

But as it engulfs the entire city, the gas network has sparked questions of safety, pricing, maintenance and durability. Are the pipelines leak-proof? How reliable is the supply? Will users have to compromise safety for convenience and low pricing?

In BEL Colony and HSR Layout, where GAIL commenced the gas supply in 600 houses, residents were hesitant at first. They too harboured these fears. But two months after the shift from LPG, the system has instilled a sense of confidence. Anurag Jain, whose HSR Layout apartment was one of the first to get the connection in the city, notes that the low pressure of the gas at the final point gives no scope for any danger.

Compared to the risks associated with gas cylinders, piped gas is much safer and convenient to use, points out Jain. “Whenever there is a variation in pressure, the system has built-in alarms to alert GAIL personnel. I had used PNG in my Mumbai home for three years with absolutely no problems. That gave me the confidence to grab the opportunity and apply for the connection here.”

Fears unwarranted
Dispelling fears of leakage, GAIL’s general manager (Projects) Partha Jana informs that every joint in the steel pipelines is radio-graphed for any anomaly. The joints are present at every 12 metres in the network.

These 18-inch main pipelines have been laid along the Outer Ring Road, passing through Hebbal, Hennur, Mahadevapura, HSR Layout, Singasandra and other areas. But what about the 5-inch Medium Density Polyethylene (MDP) pipes that branch out from the steel pipelines to enter residential areas?

Jana explains that the pressure in the MDP pipes is reduced to 4 bar from 19 bar inside the steel pipes (bar is the metric unit of pressure). This is further regulated to 21 millibar once the pipe is linked to the stove in the kitchen. Barring the one that enters the kitchen, all other pipes will be underground.

Yet, more questions linger. Bengaluru roads are notoriously dug up frequently by multiple agencies that often fail to consult one another before taking up underground projects. What if the MDP pipes are accidentally damaged?

HDD method
To tide over these issues, says Jana, GAIL Gas has adopted Horizontal Directional Drilling (HDD) method. This is a steerable, trenchless procedure to instal underground pipes in a shallow arc along a prescribed bore path by using a surface-launched drilling rig.

This, he adds, will have minimal impact on the surrounding area. To ensure that HDD does not interfere with existing utility lines, pilot drillings are undertaken. These could go as deep as 25 mm to 12 inch. At its deepest, the pipelines could be up to 1.2 metres below the ground.

But Bengaluru’s topography is so varied and utility lines criss-cross so much that HDD is not always the best option. The alternative is traditional digging. The GAIL official says the MDP pipes are laid below the existing utility lines and topped with bricks and warning mats.

In June, GAIL had commenced gas supply in 568 houses of BEL Colony, 178 in HSR Layout and 28 in Jindal Colony. The infrastructure is ready for another 10,750 houses while 6,189 houses are at an advanced stage of getting the domestic supply.

Road ahead
The ultimate objective is to ensure 1.32 lakh domestic connections in the city over the next five years. That would mark a major achievement for GAIL, which had taken up the City Gas Distribution project drawing from the 1,000 km long Dabhol-Bengaluru pipeline. Work on the high pressure pipeline from Dabhol, covering vast stretches of Maharastra, Goa and Karnataka, was completed in 2013 at Bidadi.

GAIL had set up a gas tapping station at Sulivara near Bidadi to later link it to Bengaluru through the Outer Ring Road. In the first year, gas supply will start in BEL Colony, HSR Layout, Jindal, IISc, ITPL & OBCL, Peenya bus depot, Kamalanagar, Hennur and BHEL. Areas scheduled to get the piped gas in the second year include  HAL, Silk Board to Shantinagar and Mall-eswaram.

In the third year of its operation, GAIL will supply the gas to Kasturi Nagar, BEML, Yeshwantpur, Sanjay Nagar, RMV Extension, Koramangala and Electronics City. Jayanagar, JP Nagar, Yelahanka, Sahakarnagar, Domlur and Indiranagar will get the gas in the fourth year.

The fifth year will see the PNG network reaching areas such as Sarjapur Road and Banashankari. Registrations for new connections are currently open in HSR Layout, Bellandur, Dollar’s Colony, Mangammanapalya and Singasandra. Once a technical feasibility study is conducted to ascertain whether the neighbourhood is conducive for the pipeline, the connection is initiated. Applicants will then have to surrender their LPG cylinders and get into a fresh agreement with GAIL.