Can I combine tanks / cylinders for more storage?

[cng-ohio]

Simple question. Can tanks be combined for more CNG capacity? If so how and what types should be combined (1-4)? Rules of thumb? It would increase capacity of our National Guard HMMWV project. We are pretty new to this and have already hit the ground running with our Green HMMWV Project - thanks! Our project HMMWV is used for TRAINING USE ONLY and is primarily used OFF ROAD - FYI.

[larrycng]

Re: Can I combine tanks / cylinders for more storage?

You can add as many tanks as you want (stay within the vehicles GVWR). NFPA 52 has the basic guidelines for system component installation.

The tanks can be of any type (1 --4) as long as they have the same pressure rating or higher as the fill connector (3,000 or 3,6000 psi) and they are NGV2 or FMVSS304 compliant (no ISO 11439). I would recommend that the tanks all have the same type of cylinder valve (electric or manual). All tanks should be mounted in accordance with the tank manufacturer and NFPA 52 requirements and recommendations. Oh yes and make sure the tanks that are inside the vehicle are "bagged" and vented to the outside to prevent cng from escaping into the passenger compartment. All tanks inside and outside should have appropriate shields.

Those are the basics, hope it helped. There are some good people in your area that can do inspections and make sure that your show piece is safe. Do it right, CNG vehicles can always use good press.

Larrycng

[cng-ohio]

Re: Can I combine tanks / cylinders for more storage?

Thanks! We will make sure that we represent the community well...

[Wellarmed]

Re: Can I combine tanks / cylinders for more storage?

It looks like the Larrycng gave some good advice for your tank addition(s). I agree with Larry that it is good practice to stay with the same type of tank/shut off valve, as it will ease the burden of future service. I noticed that you mentioned that the vehicle was mostly going to be used in off road service. If the tank was going to be installed in the undercarriage then I would lean towards a type 1 cyl of all aluminum construction for two reasons. #1 would be the great potential for impact damage(even with shields), and #2 would be that Ohio=rust. In addition the vehicle that you will be installing the cylinder in will be subjected to extreme levels of articulation if used offroad. Chances are you will feel a noticable decline in body flexing after the addition of an underbody cyl. Just be sure that you account for the body flexing when mounting your cylinders, because with the suspension unloaded there may be more than adequate clearence, which may disapear when the vehicle reaches maximum deflection. I would also go over kill on your stress loops in the fuel lines to prevent cracking. If the clyinder is mounted top side, then please disregard this entire post. Good luck

[larrycng]

Re: Can I combine tanks / cylinders for more storage?

sounds like some good decisions. Make sure that you have some "heavy duty" guards/shields especially on the underbody tanks..


Larrycng