How to determine the area that is affected by a pipeline failure

Risk = (Likelihood) x (Consequences of events that results from failure)

So, how do you specifically address the “Consequence” portion of the above risk equation in case of a pipeline failure?

No need to reinvent the wheel or do complex calculations. The formula is already available –

The radius of impact of the impact circle (r) = (0.69)*d*(p)^0.5

where,
d = Outside diameter of the pipeline (in)
p = Pipeline segment’s maximum allowable operating pressure (MAOP) (psig)
r = radius of the impact circle (ft)

The Headache Of Third Party Damages (Part 2)

The Headache Of Third Party Damages

It is good to be optimistic but let us get realistic. No matter how much you try to stop; somebody somewhere will damage your gas pipeline and you will have to run and put all your energy in fixing it. That ‘somebody’ is universally referred to as ‘third party’.

Here is my perception about the ‘perception’ people in society have about third party damages –

If an electric cable or water pipeline gets damaged leaving you in dark or without water, general reaction from people is,

“You see, one has to be careful while working near electric cable or water pipeline. It has direct impact on our lives.”
“Why don’t people working around electric cables or water pipeline get information before they dig?”
“These people working on road damage electric cable and water pipeline and we have to suffer. People who damage electric cable or water pipeline should be punished.”
Blah Blah…

But if a gas pipeline gets damaged by a third party, there is a high probability that general reaction from people will be one of the following –

“These gas companies don’t follow safety guidelines.”
“Their gas pipelines are just below the surface and don’t have enough top-cover.”
“These gas companies don’t protect their pipelines”
“There is a complete lack of safety.”
…
Yes, it is an ‘inconvenient truth’ ;-) that unlike other utilities, a gas utility is held accountable when a gas pipeline gets damaged. Regardless of this perception, ‘third party damage’ is a headache of gas distribution companies. 

In my subsequent posts, I will share some of my thoughts on how we can avoid third party damages and leverage technology in doing so.

PNGRB vs IGL, Part-II begins...

So, couple of years back we had this question: Who is authorized to grant CGD licenses?

After receiving answer from Supreme Court on this, now we have a new question...’Who can regulate the gas tariff for CGD companies?’ :) 

Though, Delhi High Court has recently said that PNGRB did not have the authority to fix tariffs, PNGRB has decided to go to Supreme Court…(Reference: Link) and thus…(drum roll sound please) PNGRB vs IGL, Part-II begins… I appreciate IGL’s spirit in fight against PNGRB :)

Number of PNG consumers compared to LPG consumers

If someone asks you, ‘What is the % penetration of PNG consumers compared to LPG consumers in India?’, what would be your guess?! 5%?, 10%?, 15? or 20%?!!!...I might have guessed between 5% to 10%.

But, the reality is different. It is just 1.19% as of 24 Nov 2011. 

As per the official news release by Government of India, against a total of 1,328 Lakh LPG consumers, there are only 15.88 Lakh PNG consumers in the country. 

This is a clear indication of potential ahead for City Gas Distribution industry in India.

As I always say, Let there be Light Gas! :)

PNGRB Vs IGL: Supreme Court Decision

I have received couple of e-mails asking about the result of the PNGRB Vs IGL case in Supreme Court. Actually it is my mistake that I missed to post the final part after my initial two posts on this subject.

Following are the highlights of what Supreme Court said:

• PNGRB can process CGD licenses to provide PNG and CNG 
• PNGRB cannot process authorisations for areas where licences have already been issued by the central government (e.g. Ghaziabad) 
• Fill up all vacancies on the board 

You may refer to this link for the news (dated12 May 2011) in detail.

Effect of altitude on gas pressure

Does gas pressure increase with increase in altitude? Yes, it does! Believe me. :)

Effect of Altitude on gas pressure is an interesting topic and I used to discuss this with my colleagues in my earlier city gas company and people working in planning, design, projects and O&M departments would be interested in this.

Let’s see this through Fluid Mechanics basics.

We know that, Atmospheric pressure is about 1013 mbar at sea level. = (A)
It becomes less as altitude increases. The reason is simple: Weight of the column of air is reduced.

Now, pressure at the depth of this column is = h (height of column) x d (density) x 9.81 kg/m3. (Let us call this as ‘Equation-X’). Now with this equation as foundation, let’s start our investigation.

Take a rise in altitude of 100m. At 100m above seal level the atmospheric pressure will be less by an amount equivalent to the pressure caused by a column of air 100m high.Hence, assuming air density as 1.248 kg/m3, pressure exerted by this column = 100m x 1.248 kg/m3 x 9.81 = 1224 N/m2 or 12.24 mbar = (B)

So, atmospheric pressure 100m above sea level is = (A) – (B) = 1013 – 12.24 = 1000.76 mbar

This was for air, but what happens to the gas? Here the things get interesting,

Assuming specific gravity of gas as 0.5 (for calculation sake), considering Equation-X above, pressure of 100m of gas will be = 100m x 1.248 kg/m3 x 0.5 x 9.81 = 612.14 N/m2 or 6.12 mbar

Thus , the gas pressure reduces by 6.12 mbar when the atmospheric pressure reduces 12.24 mbar.

The consequence of this is an apparent increase in gas pressure of 6.12 mbar for every 100m increase in altitude.

Based on above logic, following is the general formula which states the relation between difference in pressure and altitude.

Pressure difference = 0.12 x h x (1-S) mbar
(Where, h = height in metre, S = Specific Gravity of gas)

So from the formula above it is obvious that if the gas is heavier than air, then the difference will be decrease in pressure NOT increase. :)

Hope you find this helpful.

Let there be Light Gas! :)