# Natural Gas May Have No Odor



## Tommy plumber (Feb 19, 2010)

I just received October-December issue of "Plumbing Standards" from the American Society of Sanitary Engineers (ASSE). The following is an article on natural gas:

"There is a very well kept secret in the plumbing and mechanical fields of our industy: natural gas does not always smell like rotten eggs. Natural gas, as most of us know, is odorless and tasteless in its natural state. The odor, known as Mercaptan, is added by gas companies when it enters their distribution systems. Federal regulations require this, but they do not regulate how much or how often; that is left to the gas companies. These regulations, sadly, do not ensure that the gas supplied to your appliances will have that rotten egg smell.

The secret is called odor fade and the gas companies have known this for decades. For various reasons the gas companies have chosen, until very recently, to not pass this information along to the mechanical industry or the using public. The smell may be reduced or even completely removed from the distribution piping in the system. Several reasons for this are known:

1) new piping absorbs the odor additive
2) cutting oils removes the odor
3) dirt or debris in pipe can eliminate the odor
4) moisture in the pipe can remove the odor
5) stagnate or seldom used sections of pipe can reduce or eliminate odor

There are still more reasons, but the aforementioned are enough for this article.

You may be asking, "If the gas companies knew about this, why didn't they inform the rest of us; the installers and the users?" You be the judge. I have opinions, but they are only opinions and are not proven as fact.

Recently there have been several highly visible lawsuits filed. The Conagra (Slim Jim) plant in North Carolina; a pork processing plant in Missouri; a water heater explosion in Northern California; a Hilton hotel in San Diego; a residential space heater in Arizona. These are just a few that I have been involved with during the past couple years.

Have you ever, or do you know someone who, while attempting to light a water heater, space heater or other gas supplied appliance which stubbornly refused to light, continued to attempt to bleed "air" from the system only to have it ignite and blow back in your face? Did you tell others about this and recall that the gas had no odor? No. Not wanting others to know how stupid you were, you just took your singed eyebrows and shut your mouth. Fortunately, the majority of these explosions are small and cause little, if any, damage and therefore are never reported. Thus, we do not spread the word or learn about odor fade.

The secret is now out and it is time to spread the word. The natural gas you use may not have an odor when it reaches the point of ignition. These recent explosions have caused the federal government to do some investigation and caused code bodies to add new purging requirements to their codes. Obviously, purging or bleeding out the air indoors is taboo, but if it must be done, a Combustible Gas Indicator (CSI) is required. Natural gas will ignite and explode when it reaches approximately 5% but less than 15% of the volume of air in the room. These new regulations will even specify the type of pipe used to bleed to atmosphere. An inert gas, such as nitrogen, has been required for large bore pipe, but I suspect it will be required for small bore pipe in the future. All of these requirements will doubtlessly add to the cost of doing business. The cost of a CGI is approximately $ 3000.00 and nitrogen is not cheap.

Getting back to the responsibility of the gas companies; they are required to add the Mercaptan and perform periodic tests on their system to insure the continued presence of the smell. There is some evidence that this is not always done regularly or properly. The equipment used is not always maintained to manufacturer's specifications, the location of tests are not always appropriate or a good example of the cross section of the system and the timing between tests is not always adhered to.

I could go on and on, but the message would still be the same: the natural gas delivered to you may not have an odor when you use it. Natural gas is a highly explosive gas and if the utmost care is not used when working with it, you may not wake up to smell the roses tomorrow."


I typed the article in its entirety because I felt it was important to do so. It was written by a master plumber named: Paul Bladdick.


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## OldSchool (Jan 30, 2010)

treat fuel like electricity...... just because you cant smell it or see it doesn`t mean its not here


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## ToUtahNow (Jul 19, 2008)

Actually odor fade is pretty well known but has always been considered a problem with large distribution lines. That is why new lines need to be "pickled". There is a ton of questions about the story that don't make sense. When it is all said and done I am guessing it will be an unqualified person who was injured in the WH accident.

Mark


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## Proud Plumber (Sep 15, 2008)

Odor or not gas pipeis becoming a huge problem in this country.





[YOUTUBE][/YOUTUBE]


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## RealLivePlumber (Jun 22, 2008)

I used to live about 2 miles from there. That is my old stomping grounds. 

Last week, there was one in Cinnaminson, NJ. It was 4 blocks from my brother in laws house. 

Google it, there are a bunch of videos on you tube.


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## PLUMBER_BILL (Oct 23, 2009)

RealLivePlumber said:


> I used to live about 2 miles from there. That is my old stomping grounds.
> 
> Last week, there was one in Cinnaminson, NJ. It was 4 blocks from my brother in laws house.
> 
> Google it, there are a bunch of videos on you tube.


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I wonder if this gas had an odor?

Redwood ????? 

http://www.plumbingzone.com/f13/bre...n-connecticut-7386/?highlight=plant+explosion


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## easttexasplumb (Oct 13, 2010)

It seems to me that the gas suppliers here put more mercaptan in the system in the summer time than winter. I went to a huge industrail building one summer they made the empleyees go outside because the smell was that strong. The only leak we found was small bubbles on a coupling, made repair and system help 15 psi.


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## Proud Plumber (Sep 15, 2008)

I saw the video I posted on the news this past week. The news story went very indepth on huge pipe line infrastructure problems that are not being talked about. It mentioned an explosion in Calif. that the gas company did not even know what kind if pipe they had in the ground. 

Just a sarcastic suggestion... now that people have died maybe we could put people to work replacing it... I am sure our banks would be willing to offer discount loan rates to gas companies... After all the same people out of work are the ones that funded there bailouts.....


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## Redwood (Sep 8, 2008)

PLUMBER_BILL said:


> ----------------------------------------------------------------------
> I wonder if this gas had an odor?
> 
> Redwood ?????
> ...


Yea it had plenty of odor...
Too much in fact... :laughing:

A large number of workers bailed out for the day and others left the area and were in construction trailers on the front side of the building away from the explosion side because of the odor. No doubt the odor saved a large number of the workers that day.

Almost a year later they are finally near the end of construction and getting the plant ready to go on line. They recently did the line clearing blows only this time they did not use natural gas and the event went off smoothly. They just recently ran job ads for Plant Operators.

As far as the OSHA Fines and Lawsuit Settlements, OSHA issued the 3rd largest set of fines in their history totaling $16.6 million http://www.safetynewsalert.com/kleen-energy-explosion-osha-issues-third-largest-fine-ever/ and the Lawsuits are still pending for the 6 dead and 50 injured workers.

I was figuring that I'd update that other thread when I can see the exhaust rising from the stacks which should be soon.

See the before and after pics below...




























The blast was centered in the courtyard between the 2 stacks and the heat recovery boilers when they were purging the natural gas line using high pressure natural gas and the gas level in the courtyard reached explosive levels. The sound and ground rumbling was felt across much of the state with people on the shore and up near the Mass border thinking it was a sonic boom....

See the picture below showing the radius of where people reported hearing and feeling the blast.


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## DIZ (Nov 17, 2010)

http://www.atv.ca/victoria/4994_74409.aspx

WHen you smell gas, dont use a lighter in place of a flashlight. Smell gas, clear out if you dont know what you're doing. Unlike the whiz in this story....Macgruber!


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## Tommy plumber (Feb 19, 2010)

I never heard of 'odor fade' until I opened my mailbox the other day and read that article in ASSE's magazine. I have singed my eyebrows when trying to light a gas W/H.


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## 19jacobpratt90 (Jun 13, 2011)

lol learned something new today.... its nice to know about but rlly always have to be carefull when ur working with nat or any gas really


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