ADVISORY - LP GAS HOSES ON T1N AIRSTREAM INTERSTATES

Our friend's 2007 Airstream Interstate (same year as ours) developed a leak in its propane fill line.  An uncontrolled release of propane would occur every time he attempted to fill his tank.  Needless to say, this was acutely dangerous, so he had it repaired at a commercial RV facility in the greater Houston area.

I helped to research the issue to understand more thoroughly why the failure happened, and what we owners of this vintage of Interstate should do in the face of it, if anything.  Here's a summary of my findings.

This is what the removed hose segment looked like (I retrieved it from the repair facility to study it).   There was no visible damage or wear of any kind on the hose.  I could not see any tears or breaches.  A repair shop representative had stated to me that, not only was it leaking, it appeared as if it might be leaking from more than one location.  

And these were the identifying markings on it.

Those letterings are very difficult to read, so let me summarize as best I can make them out:

LP GAS HOSE
PARKER SS25UL-9
MAX. WK. PRESS 2.4 MPa (350 P.S.I.G.)
2-8 10MM (13/32)
2-1006
MH8749

Here are a couple of pics of the replacement job:

That's a new segment of hose on the left - the fill line.  And a segment of OEM hose on the right. 

And some additional detail on the replacement hose (bottom segment).  Both of our rigs have propane fill ports on the street sides of the vehicles, whereas the tanks themselves are mounted under the chassis at the curb sides.  So the fill line runs all the way underneath the vehicle.  I took this picture looking upward at the underside of his chassis.  

According to the repair facility, no OEM stock item was available as a replacement for this hose.  They had to contract out for the fabrication of the new hose segment.  Here's some of the stenciling detail on the product that they chose:

FLAME RESISTANT MSHA 2G-11C
8M2T-MTP MegaTuff (R)
35.0 MPa (5000 PSI) 3/8"

Obviously the specs on the replacement suggest a greater durability and construction standard than the original.  A hose of this higher caliber may not strictly be required for this application, but as with many repair jobs these days, labor is so much more expensive than materials that one might as well use the best quality materials available whether they are strictly needed or not.

The obvious question is, why did the original hose fail?  Our rig has visually-identical LP hose segments, so the answer figures into our decision tree about how to manage our propane system going forward.  We had our propane tank replaced about a year and a half ago (blog post here) but the hoses were not replaced simultaneously because there appeared to be no problem with them.

Researching this type of hose on the internet, I came across this Consumer Products Safety Commission recall of a hose from the same manufacturer and same technical specification.

I screengrabbed it in case it disappears from the internet. 

I then phoned the manufacturer Parker Hannifin Corp. to get more details.  Obviously the recall was on an older hose lot, but I didn't initially know how to interpret the markings on this one.  I spoke with two customer service reps who told me the following:

• The marking "1006" indicates the hose was manufactured in October 2006, which is consistent with the age of our rigs.  
• "MH8742" indicates a technical standard.  In this case, and as the CPSC recall notice confirms, this type of hose was typically used in consumer-grade gas BBQs.
• The rep stated that a leak emanating from a 10-year-old segment of this hose is not an unexpected event.  A hose that old is near the end of its useful life; they don't last forever.  If the hose had been years younger and developed a leak, they (Parker) might be interested in retrieving it to study what happened.  But not a hose this old.

This particular hose failure occurred near a time when many of us are extremely interested in learning what transpired to cause the Roadtrek fire in California just a few weeks ago - that vehicle was also a T1N Sprinter-based Class B RV of similar vintage to ours. That incident appeared as if it might be linked to an uncontrolled release of propane, but to date, no story is known to have emerged regarding the cause (see this Air Forums thread for discussion as well as this Class B Forum thread).  I'll leave you with the full live news video of that event as it unfolded, as you ponder the question of how to manage your own propane system.