USCG fuel tank regulation for pressure testing

I have older 1970 Monel metal fuel tanks which are installed in an Egg Harbor.

Does anyone know if the USCG tank pressure test has changed significantly since 1970? Did they even have one? I imagine they did. I emailed and called USCG today to ask them.

Would the tank maker, "Seafarer" have been required to meet such a pressure test in 1970?

I have in mind a max working pressure of 1 to 1.5 psi.
The USCG test is at 3 psi.

http://www.uscgboating.org/assets/1/AssetManager/ABYC.1002.01.pdf
From the fuel systems PDF page 107

The tank should be empty for this test. Testing pressure can be supplied by pressurized air or compressed inert gas. The tank's rated testing pressure is marked on the tank, but in no case will it be below 3psig. During the test, the sides, top and bottom of the tank should be accessible. All openings except the one used to admit the pressure should be sealed.

The usual is to install a tall fill hose where the fuel height can be measured.

The tank can bend buckle and look like crap, but if it dies not leak its fine.

Why on earth would you need a test , going to carry passengers under Sub. T?

If the tank is not yet installed , water can be used for the test , with different column heights for specific pressures.

For a simple leak test, 1-1.5psi is a good idea. There's no need to add the extra stress of 3psi. Bring up the pressure and let it sit and see if it holds. What I usually do is just take off the vent hose and put the gauge and air adapter there. This way it also checks your fill.

Ken

Our new tanks were tested at 3 psi under 33 CFR 183.510(a), built in accordance with ABYC & NMMA regulations, and meet ISO 10088 specifications, according to the manufacturer.


When we were specifying the tanks, some manufacturers quoted a smaller testing PSI.

I think since we are an uninspected vessel, there were no specific USCG additional regulations.

Why are you testing your tanks?

It looks like the 3 psi is a standard but I could be wrong. Understanding the rules is difficult at best. This came from a USCG Compliance Guideline. The same ones you referenced but a different section.

183.510 Fuel tanks.

(a) Each fuel tank in a boat must have been tested by its manufacturer under Sec. 183.580 and not leak when subjected to the pressure marked on the tank label under Sec. 183.514(b) (5).

[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]Each fuel tank must be tested to see if it leaks. This leakage test includes all fittings supplied as part of the tank. [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman]
[/FONT][FONT=Times New Roman,Times New Roman][/FONT]TEST PRESSURE

[FONT=Times New Roman,Times New Roman][FONT=Times New Roman,Times New Roman]The test pressure must be the greater of 3 Pounds per square inch gauge (psig) or 1-1/2 times the pressure created at the lowest point in the fuel system when the fill or vent line, whichever is lower in height, is filled to its top with fuel, as indicated in 183.542. A 3 psig test will cover installations whose height from the lowest point in the fuel system is 6.4 feet to the lower of the fill or vent. See Figure 5 for height covered by various pressures. These heights refer to a head of gasoline and take into account the one and one-half times the head. The determined pressure is the minimum pressure that must appear on the fuel tank label. For the test procedure, refer to 183.580. Normally, the test is conducted by the tank manufacturer who applies the tank label. The boat manufacturer is responsible for determining that this test has been performed on the tank, in addition to the fuel system pressure test required by 183.542. [/FONT][/FONT]
[FONT=Times New Roman,Times New Roman][/FONT][FONT=Times New Roman,Times New Roman][/FONT]

Yes, today the static test pressure is 3 psi, without leaking.
Back then in 1970, I just don't know I email and called USCG to ask, do they respond?

I am replacing the old fuel fills to the newer vented Perko fuel fills that have the vent coming back to the fill not going over the side.

And since they are gasoline tanks, and with this lousy E10 fuel, I was thinking to use a vopr style EPA emissions cap, which I think will help preserve the fuel better than with the old style 5/8 wide open vent which is wide open all the time to air.

I set the cap pressure to 0.85 psi, the standard for both Perko and Attwood is 1 psi before they vent tank pressure to atmosphere. the idea is simply less air exposure to the fuel as these type caps are normally closed.-sealed from the outside air, only opening when the pressure changes beyond say that 1 psi set point for pressure. They offer no restriction to fuel pulled from the tank.

Sounds like a good plan and also nice on the gold standard for tanks.

It's too bad you can't get non-ethanol fuel. Why do some states have it and others don't?

Monel tanks - Bravo!

Mid 20th Century Eggs were built with quality in mind...

Yes, nice 145 gallon monel tanks made from sheet metal.

The sheets have no square corners, they are rounded over like a tube then are joined in a long continuous weld the entire tank length. On end it looks squarish in profile with rounded large radiused corners. Around 8 foot long, 18 by 18 inches, but this is a guess.

The welded edges on the ends and side look like they are done by a machine process, very nice looking, perhaps the sheet was folded, and welded electrically.
And I can see where it has welded internal baffles every 15 inches or so.

The monel is thick enough you can not press on it and notice any movement.

The bronze fill pipe threads into tank top.
I cut it lower to accommodate an adapter I made since the new fuel fill hose is 1.5 inch. The adapter will fit between tank and fill.
I also used a Perko inlet check valve inline in the hose, available for diesel or gas.
PERKO Inc.
That prevents fuel from flowing back up the fill pipe.

And putting an Attwood fuel demand valve on the tank pickup, blocks fuel flow out the tank unless demanded by fuel pump.
http://www.attwoodmarine.com/store/product/portable-fuel/fuel-demand-valve
A cool thing really, no fuel can flow even if tank is under pressure.


some pics
Perko EPA compliant sealed cap modified to VOPR style cap

Cutting the old fill pipe lower. And stuffed in a wet sock so fumes cant ignite from the saw.
Perko fuel redesign modernize

Here is a video explaining the new style VOPR pressure system. You can either use charcoal cannister or the VOPR system.
The FLVV and grade valve are only useful for helping prevent an over filled tank as they want ullage space in the tank now.

I modified the VOPR valve to set it to 0.85 psi open PSI. The standard is 1 psi.
My one concern is stressing the tank, I could set it lower to 0.5 psi.
With a VOPR emissions style cap, cap is normally shut unless pressure exceeds the set point, then it vents to atmosphere. So it ought to help keep moist air away from the gas versus having a 5/8 hose wide open all the time.

Monel tanks - Bravo!

With the current price of new boats it is criminal that ALL are not equipped with real fuel tanks.

FF said:

Monel tanks - Bravo!

With the current price of new boats it is criminal that ALL are not equipped with real fuel tanks.

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Agreed

Monel tanks are only as good as their design, install and fabrication. Building integral tanks on Fe, Al or FRP hulls is quite suitable and much more cost effective than using a Ni Cu alloy set of tanks specially made to fit a hull form.

sunchaser said:

Monel tanks are only as good as their design, install and fabrication. Building integral tanks on Fe, Al or FRP hulls is quite suitable and much more cost effective than using a Ni Cu alloy set of tanks specially made to fit a hull form.

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Back in 1970, Monel metal was likely cheaper than today. I had read using monel metal today is cost prohibitive.

I hope someday day we will have much cheaper titanium metal. Titanium is super abundant, and durable.

Titanium is the ninth most abundant element in the earth's crust and is primarily found in the minerals rutile (TiO2), ilmenite (FeTiO3) and sphene (CaTiSiO5). Titanium makes up about 0.57% of the earth's crust. Titanium is a strong, light metal.

Click to expand...

sunchaser said:

Monel tanks are only as good as their design, install and fabrication. Building integral tanks on Fe, Al or FRP hulls is quite suitable and much more cost effective than using a Ni Cu alloy set of tanks specially made to fit a hull form.

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However... Unless I am incorrect... Monel material tanks will outlast all other gasoline/diesel tanks.

It's not the new or a decade or even the two decades old boat owners who have real need to worry about fuel tank failure. IMO - It is the hundreds of thousands of three, four, five decades and beyond that age boat owners who should have the security that monel offers.

Our good condition, 40 yr. old, Tollycraft has its original aluminum tanks. I do my best to keep them free of water contact inside and out. They still seem to be in good condition... how much longer is a guess?? If they were monel I'd feel considerably more confident that decades of leak free usefulness still remained.

#1 importance is that through hulls remain leak free... #2 of importance is that fuel tanks remain leak free too!

sdowney717 said:

Back in 1970, Monel metal was likely cheaper than today. I had read using monel metal today is cost prohibitive.

I hope someday day we will have much cheaper titanium metal. Titanium is super abundant, and durable.

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Back in the 60's/70's monel was considered expensive.

Titanium a good material for fuel tanks that could last as long as monel?

When I was a kid I had a summer job at a Reynolds Aluminum warehouse. Next door was an outfit that pressure tested, cleaned and did weld repairs on tanker trucks. One day there was an enormous whooomp ! We all went outside to see what had happened. The entire roof of the building had lifted up and landed back on the walls slightly askew. There was a 3' diameter hole in the roof and we found a foot in our parking lot.

These guys supposedly were the experts. Amateur pressure testing a gasoline tank ..... unadvised.

boatpoker said:

When I was a kid I had a summer job at a Reynolds Aluminum warehouse. Next door was an outfit that pressure tested, cleaned and did weld repairs on tanker trucks. One day there was an enormous whooomp ! We all went outside to see what had happened. The entire roof of the building had lifted up and landed back on the walls slightly askew. There was a 3' diameter hole in the roof and we found a foot in our parking lot.

These guys supposedly were the experts. Amateur pressure testing a gasoline tank ..... unadvised.

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Now - There is a lesson in words!

Thanks for sharing.

Art said:

However... Unless I am incorrect... Monel material tanks will outlast all other gasoline/diesel tanks. !

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Again, integral tanks was my point. This type of construction is not new, just becoming more popular as a space saving, stability improver and cost containment design technique. Using Monel as part of integrated hull tank design would be unusual

Even though Monel has some decided advantages, not always enough to cause high end builders utilizing non integral stand alone tanks to switch from FRP, Al or Fe.

Art said:

Back in the 60's/70's monel was considered expensive.

Titanium a good material for fuel tanks that could last as long as monel?

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I believe Titanium will experience less corrosion than monel. Monel will corrode, but not significantly.
It may be that not all interior parts of a monel tank are monel.
I had to change out my pickup tubes. They were entirely eaten away, they were made of brass.
I drilled out the 1 inch brass NPT threaded tank fitting and soldered or silver brazed 3/8 soft copper tubing as new pickup tubes. I flared out the lower end and set them to within about 3/8 inch of the tank bottom.

Corrosion resistance properties of Monel alloy 400

sdowney717 said:

I believe Titanium will experience less corrosion than monel. Monel will corrode, but not significantly.
It may be that not all interior parts of a monel tank are monel.
I had to change out my pickup tubes. They were entirely eaten away, they were made of brass.
I drilled out the 1 inch brass NPT threaded tank fitting and soldered or silver brazed 3/8 soft copper tubing as new pickup tubes. I flared out the lower end and set them to within about 3/8 inch of the tank bottom.

Corrosion resistance properties of Monel alloy 400

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TY!

Art said:

TY!

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Here was the pickup tube made of brass, look what E10 did to it.
It has lost 6 inches. And it split. I have seen formed brass split with age.
Today the rule is no brass pickup tubes for gasoline tanks.

I was having severe problems running out of fuel with fuel in the tank!
I kept think pump issues. Surprised it worked at all.

Inside the tank is a larger 3/4 tube, and the pickup tube fits in the larger tube.

sdowney717 said:

Here was the pickup tube made of brass, look what E10 did to it.
It has lost 6 inches. And it split. I have seen formed brass split with age.
Today the rule is no brass pickup tubes for gasoline tanks.

I was having severe problems running out of fuel with fuel in the tank!
I kept think pump issues. Surprised it worked at all.

Inside the tank is a larger 3/4 tube, and the pickup tube fits in the larger tube.

Click to expand...

I can see how 10% reserve would mean nothing at all.

sdowney717 said:

Yes, today the static test pressure is 3 psi, without leaking.
Back then in 1970, I just don't know I email and called USCG to ask, do they respond?

I am replacing the old fuel fills to the newer vented Perko fuel fills that have the vent coming back to the fill not going over the side.

And since they are gasoline tanks, and with this lousy E10 fuel, I was thinking to use a vopr style EPA emissions cap, which I think will help preserve the fuel better than with the old style 5/8 wide open vent which is wide open all the time to air.

I set the cap pressure to 0.85 psi, the standard for both Perko and Attwood is 1 psi before they vent tank pressure to atmosphere. the idea is simply less air exposure to the fuel as these type caps are normally closed.-sealed from the outside air, only opening when the pressure changes beyond say that 1 psi set point for pressure. They offer no restriction to fuel pulled from the tank.

Click to expand...

Updating my experience. This VOPR fuel cap is wonderful. I have had zero trouble with fuel, no problems leaving 40 gallons in the 150 gallon tank over the winter, the fuel stays dry. The engines run great on the old fuel from last year. Every boat using gasoline fuel should be fitted with this, you don't need charcoal canister, that will expose the fuel to humid air.

All you need is the VOPR fuel fill with integrated vent tube. And the Attwood fuel demand valve in the fuel tank outlet or the Perko one. Perhaps the fuel fill valve to keep fuel from welling back up when your filling the tank is useful. The ullage valve you don't need but is potentially beneficial if you were to overfill your tank.

All through last fall, winter, spring, my tank has been basically closed off from the air by the VOPR cap. I know because everytime I opened the cap I heard no whoosh, made me wonder if it had broken. But it just had not been hot enough to pressure the tank with fuel vapors. So this summer with mid 90 days, when I open the tank, I hear the 'whoosh', like you hear on your car fuel cap when removing the cap. So it is working like I had hoped.

The VOPR cap allows a 1 pis pressure to build in the tank before it vents to air, and has caused no trouble to the tank. The gasoline is preserved, so the E10 wont suck water from the air corroding your fuel system like it does in the old conventional wide open vent system most everyone has.

Here is the Perko catalog with the part number for vpr / vopr caps fuel fills
http://www.perko.com/images/catalog/catalog_315_pdf/cat315-e.pdf

sdowney717 said:

Updating my experience. This VOPR fuel cap is wonderful. I have had zero trouble with fuel, no problems leaving 40 gallons in the 150 gallon tank over the winter, the fuel stays dry. The engines run great on the old fuel from last year. Every boat using gasoline fuel should be fitted with this, you don't need charcoal canister, that will expose the fuel to humid air.

All you need is the VOPR fuel fill with integrated vent tube. And the Attwood fuel demand valve in the fuel tank outlet or the Perko one. Perhaps the fuel fill valve to keep fuel from welling back up when your filling the tank is useful. The ullage valve you don't need but is potentially beneficial if you were to overfill your tank.

All through last fall, winter, spring, my tank has been basically closed off from the air by the VOPR cap. I know because everytime I opened the cap I heard no whoosh, made me wonder if it had broken. But it just had not been hot enough to pressure the tank with fuel vapors. So this summer with mid 90 days, when I open the tank, I hear the 'whoosh', like you hear on your car fuel cap when removing the cap. So it is working like I had hoped.

The VOPR cap allows a 1 pis pressure to build in the tank before it vents to air, and has caused no trouble to the tank. The gasoline is preserved, so the E10 wont suck water from the air corroding your fuel system like it does in the old conventional wide open vent system most everyone has.

Here is the Perko catalog with the part number for vpr / vopr caps fuel fills
http://www.perko.com/images/catalog/catalog_315_pdf/cat315-e.pdf

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Hi sd - Sounds you have things well in hand. I've never experienced fuel contamination trouble [regarding my own in-tank conditions]... due to liberal use of Soltron fuel additive.

https://www.soltroniw.co.uk/

https://soltron-gtr.com/

Please Explain

The VOPR cap allows a 1 psi pressure to build in the tank before it vents to air, and has caused no trouble to the tank.

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Please help me understand this, as we are getting ready to replace our gas tanks.

Are you saying that the VOPR fuel tank cap only allows air pressure to escape when the fuel is expanding? What about when the fuel is contracting (cooling) and needs air to relive the pressure? Does the VOPR cap also "open up" to allow some air to flow back in to the tank?

Or are you saying that because you have such well-built fuel tanks the added pressure when the gas cools does not matter?

Thank you in advance for your explanation.

Miz Trom said:

Please help me understand this, as we are getting ready to replace our gas tanks.

Are you saying that the VOPR fuel tank cap only allows air pressure to escape when the fuel is expanding? What about when the fuel is contracting (cooling) and needs air to relive the pressure? Does the VOPR cap also "open up" to allow some air to flow back in to the tank?

Or are you saying that because you have such well-built fuel tanks the added pressure when the gas cools does not matter?

Thank you in advance for your explanation.

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The air can go both ways. Works just like your car gas cap. When running and sucking fuel from tank less than 1/8 pound to open the valve. Essentially like no valve is in there, so there is no restriction for air to move into the tank. Only 1 psi top vent outwards. A car gas cap vents out at 2 psi.

It has made such a wonderful difference for my boat. Fuel stays dry and fresh all year long.

You MUST install the fuel demand valve, otherwise pressure of even 1 psi could create a fuel leak somewhere in the system. The fuel demand valve from Attwood is 3/8 inch and cheap and has worked extremely well for me. The valve will only allow fuel to be pulled from tank when fuel is sucked by the fuel pump. Otherwise it is like it is closed off. Then the only way for anything to move in the tank is through the VOPR fuel cap.
I put the fuel demand valve immediately after the fuel pick on the tank. Perko makes one that screws into the tank as a pickup combo demand valve.

Art said:

Hi sd - Sounds you have things well in hand. I've never experienced fuel contamination trouble [regarding my own in-tank conditions]... due to liberal use of Soltron fuel additive.

https://www.soltroniw.co.uk/

https://soltron-gtr.com/

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I stopped using fuel additives. With the modern style fuel system seemed less needed to me. Probably still a good idea, but people don't use that for their cars and trucks. I also think a vopr system for diesel boats would help keep water out of the diesel fuel and save people trouble and money.

Perko sells a spacer ring that lifts the fill higher off the deck. I recommend you use it. I put them under my deck fills. Helps keep water from getting into VOPR cap from heavy rain or water splashing on the deck. That is what Perko says.

sdowney717 said:

I stopped using fuel additives. With the modern style fuel system seemed less needed to me. Probably still a good idea, but people don't use that for their cars and trucks. I also think a vopr system for diesel boats would help keep water out of the diesel fuel and save people trouble and money.

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I don't think automotive comparison is valid. How many more times are you using and turning over the fuel in your vehicle compared to a boat sitting?...Not even close

Sailor of Fortune said:

I don't think automotive comparison is valid. How many more times are you using and turning over the fuel in your vehicle compared to a boat sitting?...Not even close

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Well, yeah , I know. But I have started up some of my cars after sitting for even 5 years on the fuel in their tanks and they ran fine. If the temperature does not change too much the tank wont be developing vapor pressure and it will essentially be a closed system. Plus there is a lag, the tank is insulated by layers of car or boat plus the fuel amount volume has an impact on how much heat it can absorb or release. Larger lake of fuel is more resistant to temperature changes too.