# black iron gas line and slope



## BlueBSH (Oct 29, 2009)

I was reading over an introduction to plumbing book (scary, I know..) but one section I looked at was about gas line, mainly black iron natural gas line... it stated that the line should slope downward slightly... I've never heard that before, is this standard pratice? I know the 40ft run in my house is perfectly level..

does it matter? or sould it slope downward? I assume if it is to slope its to slope downward towards the appliances that use it?


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## hvac benny (Dec 29, 2009)

You don't need to slope it.


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## ddawg16 (Aug 15, 2011)

I have never heard of that either. Are you sure they were talking about gas and not air? Some guys slope their air lines to keep water out.

Now, it is standard practice to install a dirt trap. Basically, it's a dead leg...say 6" off a T at the point of service....such as a furnace or hot water heater. This acts to trap any trash that 'might' work it's way up. Keeps it from going into the unit being served.


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## BlueBSH (Oct 29, 2009)

ddawg16 said:


> I have never heard of that either. Are you sure they were talking about gas and not air? Some guys slope their air lines to keep water out.
> 
> Now, it is standard practice to install a dirt trap. Basically, it's a dead leg...say 6" off a T at the point of service....such as a furnace or hot water heater. This acts to trap any trash that 'might' work it's way up. Keeps it from going into the unit being served.


 
nope its gas..... here's the content of the page on the book

*Notes for Installing*​*Gas Lines *
*Horizontal pipe runs must be pitched downward slightly, *​​​​either by using progressively thicker shims between pipe and
*the attachment surface, or by making progressively deeper cutouts in a support member, or drilling access holes that become*​
*progressively lower in joists.*


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## fireguy (May 3, 2007)

I think I would be carefull about following that book. Cutting notches in framing members might be as exciting as driving an old but across the country.


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## BlueBSH (Oct 29, 2009)

I was thinking it sounded odd... its a pressurized line, its not like it depends on gravity like DWV does... never heard of that before until this book


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## Jackofall1 (Dec 5, 2010)

Very odd sounding especially considering that many fittings used in line size reduction are center line transitions, thus negating any slope.

Mark


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## BlueBSH (Oct 29, 2009)

Jackofall1 said:


> Very odd sounding especially considering that many fittings used in line size reduction are center line transitions, thus negating any slope.
> 
> Mark


yeah, and I've never heard of a gas line getting clogged, I'm sure it could happen, but not like drainage lines... and we have sediment traps for most of that to start with


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## ddawg16 (Aug 15, 2011)

BlueBSH said:


> I was reading over an* introduction to plumbing book* (scary, I know..) but one section I looked at was about gas line, mainly black iron natural gas line... it stated that the line should slope downward slightly... I've never heard that before, is this standard pratice? I know the 40ft run in my house is perfectly level..
> 
> does it matter? or sould it slope downward? I assume if it is to slope its to slope downward towards the appliances that use it?





BlueBSH said:


> nope its gas..... here's the content of the page on the book
> 
> *Notes for Installing*​
> *Gas Lines *
> ...




I get it now.......

The author had one summer job working for a hack....learned all the wrong things....couldn't get a real job afterwords doing the work, so he wrote a book.

As they say.....if you can't engineer it, build it or teach it.....then you write a book or become a consultant.....

It has been my experience in court, that any time you have an 'expert witness', in reality, he is a guy who could not make it in the real world so he became an expert.....very common with uses of force and pursuits.....

In one case involving a use of force expert, I heard through the grapevine that he got his ass kicked in the field one time....then quit....couldn't handle it.....so now he calls himself an 'force expert'.....​


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## COLDIRON (Mar 15, 2009)

Most piping done anywhere should always favor the direction of flow. steam- to allow condensate to return or be trapped, gas- to slowly push anything in the system to-wards the dirt leg, air conditioning refrigeration --to ensure proper oil flow throughout the hermetic system, sewer lines to ensure proper flow of waste to the plant, air to move water content along to the tank to be drained out automatic or manual, water, liquids and other materials to make the system more effect and to not labor pumps.

I am not saying so many inches per foot as in sewer drains I am saying just favor the direction of flow not the way the product is coming from.

It's not rocket science.


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## Jackofall1 (Dec 5, 2010)

COLDIRON said:


> Most piping done anywhere should always favor the direction of flow. steam- to allow condensate to return or be trapped, gas- to slowly push anything in the system to-wards the dirt leg, air conditioning refrigeration --to ensure proper oil flow throughout the hermetic system, sewer lines to ensure proper flow of waste to the plant, air to move water content along to the tank to be drained out automatic or manual, water, liquids and other materials to make the system more effect and to not labor pumps.
> 
> I am not saying so many inches per foot as in sewer drains I am saying just favor the direction of flow not the way the product is coming from.
> 
> It's not rocket science.


Not to be arguementative, but I have been in construction for more that 35 years and most every plumber or fitter I have ever seen has used a topedo level when hanging pipe, except for drain work. 

Sloping pipe in the direction of flow will do nothing when there are size transitions installed, except maybe pool anything collected at the transition, unless the transitions are eccentric (flat on bottom) and if anything when an eccentric reducer is used the installer is trying to keep the top flat when hanging tight to joists.

In the case of gas and air there is a "valved or capped drip leg" installed at the bottom of a vertical to horizontal transition to capture any transients in the piping such as oil, water and dirt.

In the case of process water or closed loop water systems many times a strainer is installed at the point of use.

Install your piping level, as would any proffessional. 

Mark


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## ddawg16 (Aug 15, 2011)

Jackofall1 said:


> Not to be arguementative, but I have been in construction for more that 35 years and most every plumber or fitter I have ever seen has used a topedo level when hanging pipe, except for drain work.
> 
> Sloping pipe in the direction of flow will do nothing when there are size transitions installed, except maybe pool anything collected at the transition, unless the transitions are eccentric (flat on bottom) and if anything when an eccentric reducer is used the installer is trying to keep the top flat when hanging tight to joists.
> 
> ...


I would like to add......I've been in many a Aerospace manf plant.....the big boys take their facilities very serious. I have never seen any gas or air lines sloped. Jackofall is correct. 

I personally think the writer of that book is trying trying to create an issue that is not an issue.

BTW....Gas is about as 'dry' as you can get. There will be NO moisture or steam in it.....just garbage from the new pipe that may have been installed and the installer did not blow it out first.


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