Don’t paint gas pipe

Halharash

I am getting ready for a gas pressure test in NYC. I spray painted a few feet of the gas line next to the meter to make it look nice. 

Picture attached. 

Does this mean I have now committed to a 90 PSI test instead of the usual 3? 

Any recommendations on how to remove spray paint from gas pipe? 

TIA

Mad Dog_2

Uh oh......Not good.  Depends how thorough and sharp the inspector is.  I'd just be honest and tell him what you did. You could try a wire wheel but you might make it stand out even more.  Try to wire wheel the underside and see how it turns out. Good luck. Mad Dog

Mad Dog_2

Was this just on a whim? Or did someone else suggest it to you?   Mad 🐕 Dog 

Halharash

I saw the plumber spray other pipes and figured -why not?

EBEBRATT-Ed

This is always a problem.

In MA all outdoor gas pipe must be painted.

But when do you paint? It's a battle you can't win.

I have piped gas and not painted it and when the inspector shows up they say "You know this has to be painted, why didn't you paint it? What do you think I am going to come back again? You will have to pay for another inspection"

or

I paint the pipe, them I here " you know that paint can seal up a leak. Why did you paint it before inspection"

Every town every inspector is different

Halharash

Any way to remove the paint? 

Derheatmeister

I'd use a Soda blaster.
Paint stripper.Wire wheel..

ChrisJ

I'd be gladly testing that at 90 PSI before I considered sandblasting it, especially in the structure. That's going to be absolute hell.


If the piping is even reasonably tight 90 PSI should be easy.

Make sure you completely isolate any appliances and the gas meter from the system before performing such a test.

mattmia2

Chemical paint stripper would probably be the way to take it off. Pressure testing is probably the better option.

heathead

Ok so follow up question on painting gas lines. Inspection passed and inspector said I could paint gas pipe any color I wanted inside and outside has to be gray. I want to paint it yellow because the house also has old galvanized plumbing pipe and gas service is new to the area. I heard of a knuckle head unscrewing a pipe for a clogged drain line that turn out to be gas line in MD somewhere. So question is painting gas line not allowed before testing because it can mask/seal a potential leak correct? Any advantage in taping the joints as to not paint them on the inside of the house when painting gas lines inside of the house ?

EBEBRATT-Ed

Some inspectors think paint can seal a gas leak.

Also, although a lot of states allow galvanized pipe for gas here in Massachusetts they do not. Apparently, someone thought the galvanized coating could cover up a pipe defect and chip off later.

So every location has its kinks.

If you're going to or are required to paint gas pipe I would want paint on the threads because that is the most likely place to rust

BrianF

My experience working in NYC is:
•Paint on the line = 90 PSI test. 

•No galvanized pipe at all. 

•Stickers labeling the pipe natural gas every 6’ 

These days they don’t want to grandfather anything. They want the whole gas system brought up to current standards anytime you’re doing a test.

It sounds like you got away with one here. I wouldn’t paint the piping any further. Put natural gas stickers on it to designate it. 

Mad Dog_2

A 3 psi air pressure test rarely holds especially on large apartment buildings (Think The Projects)..Forget about 90 but it is worth a shot.   It might hold or have a few small leaks to fix. This happened to once as as a brand new license master plumber.  We paint ALL The black pipe on a new steam or hot 🔥 water boiler pipe and fittings with Black Magic Asphalt Paint (also used on lead bends and lead pans). We do this purely out if pride.  In my exuberance I painted the gas drop from the ceiling only. 6 feet so it would have been an easy fix.  My father in law met the inspector.   I wasnt there: Inspector 
"Beautiful job on the boiler but why'd ya paint the gas too?? Now ya gotta test the whole system at 90PSI!!!!!!"  My father in law, who is still good with his mouth and fast on his feet at 78, (US Navy, live wire wisecracking guy who at his career  apogee
Was Chief of Water Bureau for our Large County so he could spar with the best of them) Pops, quickly turned it around on the inspector "C'mon...you KNOW Triple Crown always paints all their black boiler pipe...the kid (helper) just went a little overboard with the paint. The counter attack worked...The inspectors wheels were spinning and it set him back on his 👠 heels. "Oh....yeah..thats right...just so I test soap test it  for me right now and were good.!"   Whew! Dodged a bullet...ha ha.  Never did that again...mad 🐕  Dog

TAG

Learn something everyday .....

My NJ projects -- galvanized outside per inspector ... wrap anything in the ground. Gas company paints what they do green.

Alan (California Radiant) Forbes

I've never had pipe leak. I've never even heard of a pipe leak. Sounds like an artifact.

SlamDunk

Alan (California Radiant) Forbes said:

I've never had pipe leak. I've never even heard of a pipe leak. Sounds like an artifact.

I used to believe that too but last heating season, I found a condensate return line leaking that I installed a few years ago. 1/2" black pipe bought from a big box store and cut to size. Turns out, at the nine o'clock position, there was a perfectly drilled 1/16" hole in the pipe. I didn't find it until I encapsulated my crawl space. Someone could have easily bought it and used it for a gas line.

ChrisJ

SlamDunk said:

I've never had pipe leak. I've never even heard of a pipe leak. Sounds like an artifact.

I used to believe that too but last heating season, I found a condensate return line leaking that I installed a few years ago. 1/2" black pipe bought from a big box store and cut to size. Turns out, at the nine o'clock position, there was a perfectly drilled 1/16" hole in the pipe. I didn't find it until I encapsulated my crawl space. Someone could have easily bought it and used it for a gas line.

True,
But they would've find that hole very fast with a pressure test.  A 1/16" hole, could you even pump up pressure using a hand tire pump with that size hole in the pipe?

SlamDunk

Doubt it. Just saying there was a time when I thought good threads, good dope, good torque -no need to worry about 1/4 psi leaking out.

mattmia2

SlamDunk said:

Doubt it. Just saying there was a time when I thought good threads, good dope, good torque -no need to worry about 1/4 psi leaking out.

Unless like me you dry fit something when trying to figure out a complicated offset and forgot to take that section apart and re-fit it with dope and wrenches

Mad Dog_2

Seen many barely more than hand tight gas piping with the old gray pro dope still mushy...NOT leaking.  Mad Dog 

EBEBRATT-Ed

@Mad Dog_2

We has a 600' run of 3" black screwed lo pressure gas we ran across our shop to feed 4 new roof top units in an addition.

When we tested it it leaked very slow at 100psi. You would watch the gauge and swear it was ok but the next morning it would be down 10psi or so. Finally found it. Drip cap on the riser to 1 of the RTUs was never made up was just hand tight. TG it was not the main.

Another time we subbed out some gas piping and the guys we hired couldn't find the leak and it was all welded fittings. They looked and looked and finally found the seam on 1 stick of pipe leaking. China pipe. That will ruin your day.

On more than 1 occasion we used to put a little referigerant in the pipe then blow it up with air and find the leak with a refrigerant leak detector

Alan (California Radiant) Forbes

They looked and looked and finally found the seam on 1 stick of pipe leaking.

A little paint would've fixed that right up.

BDagle

For many many years, I never had a leak in any of the gas piping I did! I always passed the pressure tests the first time! Then one day, I installed a new gas furnace in a single-family home. I was collecting my tools and taking them out to the truck, while letting the furnace run to heat the house up. I stopped to check the furnace and suddenly heard a hiss and smelled gas! I shut everything down and started to re-check the gas piping. I found a brand new 1/2" elbow that had a casting hole in it! It hadn't leaked when I checked for leaks. But whatever was holding it together had opened up! Thank God it happened before I left the job!

EBEBRATT-Ed

Holes in fittings are not uncommon. More common on cast iron than malleable but shouldn't use CI on gas

Bill_Kitsch69

Halharash said:

I am getting ready for a gas pressure test in NYC. I spray painted a few feet of the gas line next to the meter to make it look nice. 

Picture attached. 

Does this mean I have now committed to a 90 PSI test instead of the usual 3? 

Any recommendations on how to remove spray paint from gas pipe? 

TIA

* Gingerly free-up, and work (and lube? as appropriate) all gas cocks, and unions wouldn't hurt to free the collars.
* Set your test (start at 5# or as high as allowed) and call it a day.
* No need to bring the inspector's attention to anything.. forget about it.
* You can dry 'dirty' to dull the pipe with a rag just for the look of age to blend - lol.

xmorganx

What kind of pressure is the gas service in US??? Your discussion seems to indicate that you need to air test at 3 psi or 90 depending on whether painted or not which seems a bit silly on both ends (useless on one and excessive on the other). B149 (Canadian gas code) requires 15/15 in most residential and commercial applications. Painted or not. Mainline pressure is usually 60 psi, reduced to 7 inches wc (residential and some commercial) or 2 to 5 psi (fancy residential or most commercial). I have a hard time seeing what difference paint would make if you're testing at 60 x the service pressure.....

Bob Harper

High pressure testing is stupid. 3 psi for residential more reliable at finding leaks. Painting should not make any difference in the testing.

Mad Dog_2

I agree with you guys, but it's one of those "untouchable" subjects to some...Don't even go there!!! We did 3" and 4" Low pressure gas in the NYC Financial center, hundreds of feet of pipe. The Building wanted 35-400 p.si. more or less. I was duly a little nervous about leaks and KILLED the joints. Wheh!!!No leakers. Mad Dog

PACMAN

If its existing pipe and you are doing a gas test, you should be fine depending on the inspector. If it is new pipe, try to justify with the inspector by using code 406.4.1.2 in the 2022 NYC Fuel Gas Code.

ChrisJ

Bob Harper said:

High pressure testing is stupid. 3 psi for residential more reliable at finding leaks. Painting should not make any difference in the testing.

How is low pressure testing more reliable at finding leaks?

I think the whole paint thing has to do with alleged claims that paint could seal leaks but then fail later. I get it, but it is a bit much.

I find it much easier to find leaks at 100 psi than I do at 3 psi and sch40 steel pipe with threaded joints should easily handle 150 psi. If it doesn't, something wasn't done correctly.

Long Beach Ed

Buy the Chinese fittings at Home Depot and you'll find sand holes in cast fitting in the least accessible places. Don't even think of using that garbage.

Mad Dog_2

I really resent having to go to Help-Yourself Depot...it. terrible  Mad Dog

Bob Harper

First of all, the IFGC/ NFPA 54 both call for 3 psi x 10 min. or 10x the maximum working pressure. Since most gas controls allow for 14 wci/ 0.5 psi that takes you to 5 psi. The test gauge cannot be greater than 5x the test pressure. At low pressure, that means a 25 psi gauge. At 90 psi, that's a 450 psi gauge. How big must a leak be for a 450 psi gauge's needle to move in 10 min. vs. the low pressure? The low pressure test is MUCH more accurate at finding small leaks. A large leak will be evident right away.
What if an unpainted pipe passes a 10,000 psi test then gets acid spilled on it? Does the high pressure test prevent changes to the piping? The test should be based upon the test conditions at the time. Painting protects the pipe. Sch. 40 pipe is not going to be adversely affected by surface corrosion. The paint inhibits further corrosion. Most shutoff valves are rated for 5 psi. The high pressure test can blow valve seats and bonnet seals thus causing a leak. You have to isolate appliance controls valves when testing > 14 wci. by disconnecting the piping and capping it.

ChrisJ

Bob Harper said:

First of all, the IFGC/ NFPA 54 both call for 3 psi x 10 min. or 10x the maximum working pressure. Since most gas controls allow for 14 wci/ 0.5 psi that takes you to 5 psi. The test gauge cannot be greater than 5x the test pressure. At low pressure, that means a 25 psi gauge. At 90 psi, that's a 450 psi gauge. How big must a leak be for a 450 psi gauge's needle to move in 10 min. vs. the low pressure? The low pressure test is MUCH more accurate at finding small leaks. A large leak will be evident right away.
What if an unpainted pipe passes a 10,000 psi test then gets acid spilled on it? Does the high pressure test prevent changes to the piping? The test should be based upon the test conditions at the time. Painting protects the pipe. Sch. 40 pipe is not going to be adversely affected by surface corrosion. The paint inhibits further corrosion. Most shutoff valves are rated for 5 psi. The high pressure test can blow valve seats and bonnet seals thus causing a leak. You have to isolate appliance controls valves when testing > 14 wci. by disconnecting the piping and capping it.

I don't know about the 5X thing for gauges, but the way you worded that was the gauge cannot be larger than 5X. For me, testing 100 psi I'd want a 150 to 200 psi gauge.

Bronxtech

And then there’s the house at the Beach on a crawl space with the windows to the crawl space open and or missing! 

Thank goodness, we made up some of the pieces in the 300 with a wrench held back by hand , I swear, to feel the level of tightness.
Next morning after running all night after testing, the 1 1/4 “ galvanized fitting let go!!
Omg , glad those windows were there and no basement!!! 

Lesson learned, use a Vise !!!

EBEBRATT-Ed

round here we test lo pressure gas at 3-5 psi unless the pipe lenght exceeds 100 feet then you must test at 100psi.

Mad Dog_2

I'm all for pressure testing, but I think the painted pipe = 90 psi test is a bit of overkill but, then again I've seen seasoned plumbers do some crazy things to pass a gas test.   The foreman told these guys
"OK guys...you REALLY gotta kill these joints...we can't have no leaks!'  The lead guy with the Long ponytail and missing front  tooth was like. '...oh REALLY...ok..you got it..."  They told the foreman they needed Black Permatex and ALOT of quikwick

[Thin lamp wick).  What??? You can't use wick on gas!!!!!!  So, they did about 200' of 3" and 4'  they wicked only the first half of the joint so no thread would show.  They were right...not one leak. I would never do it, but they were right.   Another time another company, the inspector caught a thread sticking out and made them take hundreds of feet, with numerous branches apart.  Ouch! Mad Dog

Alan (California Radiant) Forbes

Long ago, the local AHJ made us test new gas lines with a mercury manometer. Now, it's with a glycerin-filled gauge. It just shows you how much the inspector's trusted the contractors. Perhaps with good reason.

EBEBRATT-Ed

I have herd of contractors throwing a gauge on the ground to make it stick at the right pressure. Some inspectors around here want two gauges for that reason,

ChrisJ

EBEBRATT-Ed said:

I have herd of contractors throwing a gauge on the ground to make it stick at the right pressure. Some inspectors around here want two gauges for that reason,

Mine walked up to it, said "does this even work" and let a few bursts of air out to make sure the gauge responded.


Two gauges seems ridiculous, you could just break both....

Bob Harper

ChrisJ said:

Bob Harper said:

First of all, the IFGC/ NFPA 54 both call for 3 psi x 10 min. or 10x the maximum working pressure. Since most gas controls allow for 14 wci/ 0.5 psi that takes you to 5 psi. The test gauge cannot be greater than 5x the test pressure. At low pressure, that means a 25 psi gauge. At 90 psi, that's a 450 psi gauge. How big must a leak be for a 450 psi gauge's needle to move in 10 min. vs. the low pressure? The low pressure test is MUCH more accurate at finding small leaks. A large leak will be evident right away.
What if an unpainted pipe passes a 10,000 psi test then gets acid spilled on it? Does the high pressure test prevent changes to the piping? The test should be based upon the test conditions at the time. Painting protects the pipe. Sch. 40 pipe is not going to be adversely affected by surface corrosion. The paint inhibits further corrosion. Most shutoff valves are rated for 5 psi. The high pressure test can blow valve seats and bonnet seals thus causing a leak. You have to isolate appliance controls valves when testing > 14 wci. by disconnecting the piping and capping it.

I don't know about the 5X thing for gauges, but the way you worded that was the gauge cannot be larger than 5X. For me, testing 100 psi I'd want a 150 to 200 psi gauge.

How much gas has to leak for you to be able to detect a leak on a 200 psi gauge? In the lab, they use a Bubble-O-Meter on gas valves to detect ultra low level leaks. A gas combination valve is tested to ANSI stds. allowing 235 cc/hr through the valve's main operator and 215 cc/hr through the seals of the valve. Humans can detect the odorant in the gas that equates to a level of about 1-2 ppm. This means a leak at a level of about an ounce per year. Not gonna see that kind of leak manifesting as needle deflection on a high psi gauge. Low level leaks are detected at ultra-low pressures. Medium level leaks are detected by low psi gauges. Very high pressure leaks can be detected by sound, smell, high psi gauges and the inability to even get up to test pressure on a low psi gauge. A leak that requires 89 psi will be so bad that you will easily detect it using lower pressure gear. It's simply stupid. All this does not require an electronic gas sniffer or anything else. High pressure testing endangers the public rather than protecting.