Vent locations for propane & batteries

[DROdio]

OK I want to make sure I get this right:

For propane:  is it lighter or heaver than air?  Do i want the vents at the top or bottom of the compartment?

For the batteries: same question

Thanks!

DROdio

[boogiethecat]

Propane: Heavier than air.  BIG vents on the bottom, also vents at the top to allow air to circulate.

Batteries: Hydrogen= lighter than air.  Vents at top at least, some in bottom, again for good circulation.

Remember also, if your propane tank is permanent (bolted in) you should hardpipe the relief valve vent out to the rear of the bus and up, so that if it decides to go off for any reason, the resulting plume will be aimed to the rear and up where theoretcally it won't hurt anyone if it ignites.
  I use stainless flex (3/4) from the tank to 3/4 iron pipe which then routes to the rear of the bus and comes out about halfway up, with a 45 fitting to aim it to the rear and upward, plugged with a little cork to keep bugs out.

[Kristinsgrandpa]

The 2005 National Electric Code dropped the complete section on low voltage systems (24 Volts or less, by their definition) and instead refer you to NFPA  1192-2002 Standard for Recreational Vehicles, and ANSI/RVIA 12 Volt, Low Voltage Systems in Conversions and Recreational Vehicles, 2002 edition.

The 2002 NEC required 1.7 sq. in. in the top and bottom of the compartment. I imagine the requirements are the same, just listed in a different publication.

HTH Ed

[tucsontattoo]

I have four removable propane tanks. DOT tanks I belive they are called. Do these have relife valves that should be vented to the rear?
                                   Tucson

[Dale MC8]

DOT tanks do have a vent, it's the one that pops-off when being filled. Don't try to add extra stuff to vent remotely.
FWIW
Dale

[Chuck Newman]

Check out NFPA 1192 (can be ordered at nfpa.com) and George Myers has a relevent article in this months Bus Conversion Magazine.  Don't use an older code.  Several rules have been changed in the 2005 Code.

Specific amount of ventillation is required for various amounts of propane on board.  And both the common DOT "cylinders" and the non-portable ASME "tanks" as defined in the Code have specific fastening requirements, amoung others.

Section 5.2.19 covers "Discharge from Propane Container Pressure Relief Valves".  There are numerous sub sections covering the requirements for discharge, one of which is the discharge cannot be within 3 ft of any propane buring appliance or internal combusion engine exhaust.  Also you are limited by the amount of propane you can carry.

You will find any number of people on the various bus boards who blow off (no pun intended) the NFPA and NEC codes.  But the reality is you are far more likely to injure or kill someone with a propane incident than with electrical.  If the system is not constructed to code, you may find yourself facing criminal charges, and at the least you will be facing civil suit, major attorney fees, and guaranteed your insurance carrier will not pay the claim.