![](media/image1.wmf){width="7.5in" height="5.25in"}

Aluminum baffle, with a pad underneath the steel brace the baffle was
attached to

![](media/image2.wmf){width="6.625in" height="4.375in"}

![](media/image3.png){width="6.402777777777778in"
height="4.152777777777778in"}

How a vent is placed in a MC-331 cargo tank, note the baffle directly
behind the vent

![](media/image4.jpeg){width="2.9694444444444446in"
height="3.972916666666667in"}

The two vents are from a bobtail (left) and a transport (right)
respectively. The bent vent (right) was removed from a tank that had the
aluminum baffle break loose at two location on one side of the baffle
and ended up bending the vent. I have both vents in my office. The
baffle had a "notch the size of the rod at the bottom of the vent that
was sliced in the baffle as the baffle surged forwards and backwards in
the liquid LPG as it passed under the vent. Depending on where the
baffle is and how badly it breaks loose depends on how much internal
parts are damaged.

![](media/image5.jpeg){width="7.452083333333333in"
height="5.588888888888889in"}

Baffle in a MC-331cargo tank, attached to pads, this baffle is made of
steel, the tube from the floor to the upper portion is the spray fill
opening, the spitter lines and the liquid level gauge are clearly
visible. In the upper right side and very white you can see the bottom
of one of the two vents in the tank very close to the photographer.

In regards to the application by Trinity for manufacture of an MC-331
cargo tank with baffle support clips welded directly to the wall of the
cargo tank I have the following comments in addition to the above
photographs.

As a member of the FMCSA Cargo Tank Technical Advisory Group for over
seven years and a hazardous materials program specialist for over 12
years at FMCSA I had extensive dealings with cargo tank inspection and
repair facilities and MC-331 cargo tanks having conducted over 100
investigations into compliance at such facilities and taught courses to
the industry and FMCSA enforcement personnel on cargo tank inspection
and repair regulations and how to conduct an investigation at a cargo
tank inspection and repair facility.

I contacted two facilities I have dealt with in the past regarding
MC-331 cargo tank issues and inquired about baffle repairs and total
separation of a baffle after the baffle supports failed.

According to both companies of the 25-30 MC-331 cargo tanks they conduct
internal visual inspections on in a year 30% on average have some type
of repair made to a baffle. This could be a loose bolt, a rounded bolt
hole or a bracket failure. One tank every year or two during these
inspections has a baffle that has broken totally loose. Typically if a
baffle has come loose the driver will hear it banging around in the tank
and it gets repaired prior to the five year interval required for
internal visual inspections.

In particular one facility mentioned a bracket attached to the wall of a
cargo tank where the bend in the bracket, to enable the attachment of
the baffle to the bracket, seems to fail or crack on a regular basis.

Both facilities indicated they had serious issues with the attachment of
a baffle bracket directly to the cargo tank wall. I share the same
issue. If a bracket were to fail and need welded back to the cargo tank
wall since there is no pad the repair would have to be made by facility
holding an "R" Stamp significantly raising the cost of repairing a
baffle defect. Not only that but since the repair would be made to the
inside of the tank if the company making the repair decided to not have
the tank taken to an "R" Stamp shop and use NBIC standards, how would an
investigator be able to make a determination a weld was made to the
interior of the tank?

The purpose of requiring an "R" Stamp and the NBIC standards was to
ensure weld repairs to the cargo tank wall were done in a standardized
fashion with quality controls in place.

There was also a recent hazardous materials incident involving a cargo
tank transporting anhydrous ammonia that had just completed loading and
was heading to the scale prior to leaving the facility. A baffle in the
unit broke away from all its brackets and damaged one of the units self
closing pressure relief devices to the point is broke releasing
anhydrous ammonia. The incident occurred on 4/18/08 at Agrium US, Inc in
North Bend, Ohio.

Finally it is my understanding the common practice for most
manufacturers is to place a pad under the baffle bracket. In terms of
cost and weight, the pads do not add significant weight to a cargo tank
to reduce its load capacity and the costs would be minimal to install
the pads compared to the potential for an inappropriate weld repair
failing on a cargo tank that is the work horse in the transportation of
propane and anhydrous ammonia.

I do not feel that it is a safe practice to attach a bracket holding a
baffle reducing the slosh of thousand of gallons of fluid directly to
the wall of a MC-331 cargo tank. The reality is it has been done in the
past, most likely there will be no recall to correct the defect, but to
allow it to start again or continue is unwise.

If it was such a bad concept to require pads underneath an attachment to
the cargo tank wall, how did it ever become a regulation over 13 years
ago?. My complete comments with pictures are attached.