Hadn't heard of these either, but appears to only be EPA requirement in US since 2011. Don't know about Cdn regulations.
Copied the following off a Bass-Pro web site.
http://blogs.basspro.com/blog/boat-gas-tanks
In the past if you needed a second gas tank to put on your boat so you could get the extra fishing time in, or just have it in case you ran out of gas in the primary tank, you could just run down to Bass Pro Shops and grab one off the shelf, like this Moeller Tank;
then find the correct fuel line attachment, and away you went. Well in 2011 the E.P.A changed the way fuel tanks are made to make them friendlier to the environment. Now, even with the vent open, the fuel tanks will hold 5 PSI of pressure, and boats manufactured before 2011 do not have a fuel demand valve to prevent that pressurized tank from forcing fuel into the engine when it is not needed. This can cause running issues as well as fuel leaking onto the ground or into the water depending on where your boat is parked. This is especially true of Mercury 75-115HP fourstoke engines and all Mercury Verado engines since they do not have a “needle and seat” shut off valve in the internal fuel system on the engine. With that being said, other motors that utilize the “needle and seat” system on their motors are still susceptible to having that excess fuel pressure unseating the needle and causing fuel to overflow. So if you buy a new gas tank and your boat is older than 2011, you now also need to purchase a fuel demand valve (pictured below)
and install it in the fuel line between the fuel tank and the primer bulb, with the fuel flowing in the correct direction (there is an arrow to show you this). For more on fuels check out these service tips on gasoline.
- See more at:
http://blogs.basspro.com/blog/boat-gas-tanks#sthash.SeYNoOaX.dpuf
Also, a NMMA posting.
http://www.nmma.org/assets/cabinets...Announcement Portable Tanks JUN2012 Final.pdf
Industry Service Announcement
Tank swelling will occur and is associated with a New “Low Permeation Compliant” Portable Outboard Marine Fuel Tank!!!
Many boaters this year are seeing swelling of their new portable outboard fuel tanks, which they have not seen in the past. New EPA regulations have eliminated the traditional venting in these tanks. New portable outboard marine fuel tanks will not vent below 5 PSI with noticeable swelling.
Tank swelling is the new standard condition as a result of Section 213 of the Clean Air Act implemented by the EPA. All manufacturers of Portable Outboard Marine Fuel Tanks must certify compliancy with the EPA standard: (73 FR 59034, October 8, 2008) 40 CFR Part 1060.
Portable Outboard Marine Fuel Tanks being produced and sold into commerce must be tested and certified to these new requirements. In addition, the tank must meet the ABYC H-25 standard, which is the industry design safety standard for these increased pressures.
Since the manufacture of the “old style” twist vent caps are now banned, a newly designed cap is required. The new caps must have: a tether, provide an audible “click “for closure, and seal up to 5 PSI out, but allow vacuum in. Plus the cap needs an external or integrated means to temporarily relieve pressure within the tank prior to fuel filling or connection to the engine.
The new compliant cap will cause the portable outboard marine fuel tanks to swell. The swelling is a result of the fuel vapor building pressure, because the cap must stay sealed up to 5 PSI. Some tanks may vent to atmosphere when pressure reaches 5.1 PSI, some remain sealed beyond 5PSI. All tanks must remain sealed beyond 5PSI during storage and transportation.
The new tanks have been tested to remain sealed and safe at these pressures even when swelling is visible.
Additionally there are two other cautions for the user:
1. Fuel Spray
Fuel spray is a very dangerous event that can result from the fuel vapor building pressure within the portable outboard marine fuel tank. Users should relieve all fuel pressure within the tank prior to disconnecting or connecting fuel fittings in order to avoid fuel spray. New portable
outboard marine fuel tanks include means to relieve pressure prior to filling or connecting fuel
fittings.
2. Engine Flooding and Fuel Spillage
Engine flooding or fuel spillage can occur if a portable outboard marine fuel tank is left
connected to an engine. Users should disconnect fuel lines from engines during storage or
transportation or take other measures to ensure that pressurized fuel does not reach the
engine in accordance with the engine manufacturer’s instructions. Disconnecting the fuel line
from the engine is a simple action users can take to prevent engine flooding and fuel spillage.
Be sure to read the manufacture supplied operation information that comes with each
portable outboard marine fuel tank!
