The Maintenance Council Reviews Procedures to Reduce Van Moisture

Jan. 1, 2000
Carriers, shippers, and logistics managers are aware of the problems caused by moisture contamination and internal condensation. In today's strict environment

Carriers, shippers, and logistics managers are aware of the problems caused by moisture contamination and internal condensation. In today's strict environment of dedicated logistics, kick-out clauses and penalty schedules pertaining to moisture contamination are abundant. A shabbily executed aluminum skin repair can create even more havoc when new loads are transported.

Trailer and van body manufacturers understand the carrier's concerns and are sharing their expertise to help reduce and eliminate leakage due to a compromised outer skin, a misused sealant, or ineffective maintenance technique. They are discovering the reason why moisture comes into the container's interior.

Trailer manufacturers make vans highly moisture resistant. Nevertheless, as a van body or trailer ages, normal operations and wear soon make some form of body repair inevitable. At this point, piercing the van's skin or placing a patch over some part of the body introduces the chance of van moisture contamination. The proper technique used to repair a damaged body/trailer is critical to keeping external moisture from contaminating the load.

The subject of body/trailer moisture contamination was covered at The Maintenance Council's (TMC) Fall Meeting in Tampa, Florida. Currently, the Van Moisture Contamination task force chairman, James Yglesias, and the task force members are reviewing a draft Recommended Practice (RP) on van body and trailer moisture contamination with the help of carriers, shippers, subassembly component manufacturers, and the van/trailer manufacturers.

Van body and trailer manufacturers are interested in the draft RP, because use of the recommended procedures outlined could have an effect on the van/trailer's ability to seal out dirt and moisture from other bonded or structurally assembled parts of the body. Additionally, manufacturers and trailer dealers will want to insure that their repair facilities comply with the industry RP.

Manufacturing Practices It is recognized in the draft RP that the methods used for manufacturing and connecting various components that are part of a van body or trailer are the first key ingredient in preventing moisture contamination. Fasteners that pierce the exterior of the body should be watertight. Joints between panels should contain a sealant material during assembly. When panels are attached to the longitudinal body rails, sealant should be applied between the panel and the rail.

The attachment of the front bulkhead and rear door frame assemblies to the van body should include a surface where sealant can be amply applied and remain protected after assembly. Material used in the mating of all surfaces should be free of any dirt or oils. Metal shavings produced during theassembly process should be removed from the body.

Routing air and electrical lines through the van/trailer body should be done on a vertical plane at the lowest part of the body. TMC recognizes that without this step, moisture could run down the line and into the van body, even when the line is sealed and grommeted.

An area of concern that was discussed in depth during the TMC meeting focused on the rear door frame design and its role in preventing moisture contamination. The draft RP recommends that the upper horizontal sill be configured in a way that provides a rain shed over the top-most part of the door.

TMC's task force on moisture contamination also reviewed manufacturing practices concerning doors and their fit against the doorsill. A possible recommendation in the final version of the RP will include door gasket designs that incorporate multiple water and contaminant lips.

The final RP may recommend a four-down type gasket for the bottom lower door seal for roll-up doors, according to some TMC members. Using this system, should one outer lip become damaged, there is an inner lip to prevent moisture intrusion.

The draft RP is not all inclusive of recommendations for rear swing doors. However, TMC's RP-1405, issued March 1997, Section II, includes recommendations for swing doors and outlines several gasket sealing systems.

Preventing Contamination The draft RP recognizes the importance of sealing the floor area from dirt and moisture contaminants. Included in the draft is the recommendation that the bottom surface of the floor be entirely sealed prior to installation in the van. This ensures that the floor is sealed over each crossmember.

Expressly written into the TMC RP, is a recommended practice for assembling or repairing 12" lap-board as used in van body and trailer flooring applications. The longitudinal joints between boards should allow for expansion and contraction and provide a surface for ample application of sealant as a barrier against contamination.

Where van sidewalls contact the floor, there should be a contaminate-proof joint formed by the use of sealant as an agent between the flooring and the inner part of the body/trailer bottom-rail flange. TMC's recommendation is a noncuring Butyl caulk.

A similar arrangement is recommended for aluminum flooring: a polyurethane sealant used along the entire length of flooring where it butts against the upper coupler.

The draft RP discusses both high performance and general application sealants. The types and uses of sealants form an important part of understanding how to fight moister contamination.

For high performance sealants, the draft RP highlights:

*Polyurethane: A one-component, flexible sealant that cures to produce watertight joints when used between panels. For example, polyurethane can be used as an adhesive when panels are attached to longitudinal rails. This substance also works well when primer is applied to the substrates prior to bonding. Polyurethane exhibits good adhesion to most substrates and should cure rapidly to an elastic seal that can be painted.

Typical uses for this type of sealant include sealing of top and bottom rails together, bonding the seams of front radius and nose panel, sealing of corner caps, sealing under washers of rear frame-door assembly, and many other structural areas that require a flexible but watertight seal.

*Polysulfides: A two-component adhesive/sealer designed to cure quickly at room temperature or within minutes with the application of heat. It forms a durable, high strength bond without the use of a primer and can remain flexible while maintaining its adhesion, even in high and low temperature extremes. Polysulfides also demonstrate a high impact resistance even at low temperatures unlike epoxies that crack on impact.

Typical uses for this agent are as an adhesive for bonding both aluminum and galvanized roof bows to aluminum or translucent roof panels.

*Silicones: A one-component sealant designed for seating structural materials such as glass, aluminum, steel, and plastics. Siliconeshave excellent resistance to weathering and climate extremes. Painting over silicone is not recommended.

Typical uses include sealing for glass seats, plumbing and wiring harnesses, and for applications on a prepainted surface that needs a sealing agent.

Of the general purpose sealants discussed in the draft RP, butyl-based products are exemplified as a leading low cost product that can provide a durable boundary against dirt and moisture contaminants. An additional benefit to the butyl compound is that it can be manufactured in the form of adhesive tape.

*Butyl: A one-component, low cost, durable sealant with excellent adhesion, sealing properties, and weather resistance. It was designed primarily for interior sealing of trailers, vans, and truck bodies. Typical uses include sealing the perimeter of wood and metal flooring, sealing of air and electrical lines, and sealing around most opening sills.

*Nondrying butyl: A one-component, noncuring butyl sealant used to protect against moisture and air leaks. This compound accommodates expansion and contraction between joint and seams. It also protects against corrosion and may be used for insulating dissimilar metal against electrolysis. Typical uses include most of the items mentioned above.

*Butyl tape: This is a solid preformed synthetic polymer-based adhesive/sealant tape having excellent adhesion to aluminum, galvanized steel, FRP, translucent panels, and other porous and nonporous surfaces. Adhesion improves with age and remains permanently flexible, even at low temperatures. Typical uses include roof bow adhesive, sealing between top rail and roof panel, sealing between panel overlaps, and other structural applications.

*Brushable neoprene coating: A neoprene rubber sealer that can be used in brushable form. It has an excellent adhesion, weather resistance, and sealing properties. Neoprene dries quickly to form a tough, durable seal and retains its flexibility for an indefinite period. Typical uses include sealing perimeter of roof moldings, sealing perimeter stitching of roof panel, and sealing rivet head penetrations.

Skin Repair Recommendations A key topic in the draft RP deals with body/trailer skin repair. The draft sets a minimum procedural level for broken roof and sidewall skin repairs. Many national carriers and trailer leasing companies will want assurances that these procedures are being practiced by their contracted repair facilities.

As stated in the draft RP submitted to the TMC task force, the procedure for repairing and sealing outer covering on damaged trailers:

*Adhesive Patch - for aluminum panels such as roofs, sidewalls, and front panels.

*Cut away damaged material around the area where the patch will be applied.

*Clean the area where the patch will be applied with Scotchright type pads that can be used on a die grinder. If applicable, remove old adhesive from any roof bows or top rails. A metal grinding wheel should not be used.

*Clean the area with a glass cleaner or other nonacidic cleaner.

*The patch must be applied to a flat surface. Cut out dents and kinks if possible.

*Remove any rivets the patch will overlap. Rivets in rails and rivets in posts at sheet seams should be replaced.

*Chose the patch material that was designed for the type of skin being repaired.

*The task force recommends a roof patch with a thickness of 0.04" in aluminum sheet for typical roof repairs.

*The task force recommends a side sheet and post patch thickness of 0.05" in aluminum sheet for typical repairs.

*Cut the patch at least 10 inches larger than the hole in both dimensions to allow for five-inch overlap on all sides of the patch.

*Use a pen to mark the patch area on the surface. Make sure that all of the patch area is clean.

*Apply automotive grade double-sided acrylic foam tape directly to patch. Place two 2"-wide strips along each side. Butt tape together at each corner to prevent leaks. Do not overlap tape at patch corners because this will cause patch to leak.

*Seal outer tape seams with a small amount polyurethane sealer.

*Run a 1/4" bead of polyurethane sealer around perimeter of hole.

*Heat surface in patch area.

*Install patch. Ensure that patch is centered in marked area. Put press pressure over entire patch.

*Replace rivets as necessary using the recommended replacement practice.

*Apply a bead of polyurethane sealer along all sides of the patch. A patch without a proper bead will leak.

Riveting Repair For patches installed with fasteners: *Surface preparation and patch configuration are the same for the adhesive patch.

*Driven rivets are the preferred fasteners; however, if blind fasteners are used, they must be water tight configurations.

*Polyurethane sealant should be placed on the surfaces where the patch contacts the van skin.

*Fasteners should penetrate the patch, polyurethane sealant, and van skin. Fastener spacing should not exceed 11/2" center to center.

*Fasteners can be either 3/16" or 1/8" diameter and should not be placed closer than 1/2" from the edges of the patch.

*After fasteners are installed, a bead of polyurethane sealant should be placed around the perimeter of the patch.

TMC is also including a recommendation for major repairs. The draft RP strongly suggests that repairs needing the replacement of complete side panels should be performed following the same method as the original equipment was constructed.

Condensation Issues Moisture contamination affects many carriers, especially those that are picking up manufactured products such as roll paper on a just-in-time logistics schedule. Carriers of these products are aware of these conditions and usually equip the trailer with air vent-doors. The draft RP addresses the issue of condensation. Recommendations from the task force included a call for the addition of procedures for repairing trailer vent-doors in the event of leakage or damage.

TMC's draft RP identifies four methods of determining the location of outer skin compromises for any situation where moisture contamination is taking place. These methods will also work for compromised upper air vent-doors to show broken seals or faulty door hinge fit.

The draft advises that in many cases where water is found in the van interior, it may not be the actual location of where the skin or seal has been compromised. The draft advises that it may be necessary to remove liner panels to locate the leak site and to use one of the four outlined methods for detecting the compromised area.

As stated in the draft RP, the four methods recommended for leak detection are:

*Light test - this is the simplest and quickest test to conduct. Enter the trailer and close the doors while the entire exterior is exposed to bright sunlight. A careful visual inspection of the interior for entering light will reveal potential water leak sites. Make certain that ample time has been given for your eyes to adjust to the darkness. This may take five or more minutes.

*Water test - the entire van is run through a truck wash under relatively high pressure. Immediately afterward, the entire interior is physically examined for presence of water. It is highly recommended that the van manufacturer water test each van at final assembly.

*Smoke test - a smoke bomb is fit and placed in a pan on the floor at the center of the trailer. The doors are closed and after several minutes, the entire exterior is examined for leaking smoke. This test must be run indoors unless there is little or no wind outdoors. Smoke bombs are usually available at theatrical supply stores. The interior can easily be pressurized to 0.50" wc, which will make leaking smoke much more visible.

*Ultrasonic leak detection - a sonic generator is placed in the interior of the van, and the doors are closed. An electronic detection device scans the entire van exterior. The device has a signal strength meter, which is used to precisely locate the leak site. Trailer Dealer Opens Parts Facility IS IT A GOOD IDEA to put 15 miles between the parts and service departments of a trailer dealer? Ace Chicago Great Dane did just that and is experiencing the benefits.

The company opened a 13,000-sq-ft parts facility last July in the Chicago suburb of Bolingbrook-15 miles from the service department in Cicero, Illinois. Based on early results, the separate parts warehouse has proved to be a smart move for several reasons:

1. With its location next to a weigh station on a major interstate, the company now can be easily seen from a highly traveled truck route. The main facility in Cicero has a much lower profile.

2. The 13,000 square feet is twice the floorspace the Cicero location could devote to parts warehousing.

3. By moving its parts operation to a separate location, the dealership freed up needed space at the Cicero facility.

"We doubled the size of our parts warehouse, but the net effect is

really greater than that," says Tony Goral, executive vice-president. "Our parts warehouse in Cicero was about 4,000 square feet with another 2,500 square feet of outside storage. Our 13,000-sq-ft warehouse in Bolingbrook is twice the size of our inside and outside storage combined, and our new location enables us to keep everything under one roof."

The move also gives Ace Chicago a slightly different direction in the marketplace.

"The role of our company traditionally has been to sell and service trailers," says Richard Carlson, senior vice-president. "We sold parts, but we did so to support trailer sales and service. Our new parts warehouse is an effort to really establish ourselves in the parts business."

Located in an industrial park easily seen from Interstate 55, the Ace Chicago parts warehouse started as clear space that the company could configure as it saw fit.

"The attraction is the location," says Bill Lange, group general manager and the director of the Bolingbrook operation. "Interstate 55 is a major truck route, but it also gives us easy access to Interstate 80 and 294. Plus, this is a new industrial park, and we were able to design the build-out of our space from scratch."

In laying out the warehouse, the company's main concerns were material handling and the ability to locate parts easily.

"A modern, enclosed loading dock was very attractive to us," Lange says. "We wanted to be able to bring trucks inside for loading and unloading."

Warehouse shelves, bins, and racks run parallel to the loading dock. Racks for lengthy parts such as top and bottom rails are located closest to the loading dock, making it easy to move the parts off the trailer and directly onto a rack.

Adding Inventory With 3,000 part numbers in inventory, the bins, racks, and shelves help Ace Chicago get the most out of the available storage space.

"We have doubled the value of our parts inventory since we moved here in July," Goral says.

Best-selling parts include brake shoes and chambers, flooring, and proprietary Great Dane trailer parts. However, the company has added a few new lines, including walk ramps, bulkheads, decals, and liftgates. The company also works with Carrier and Thermo King to sell parts for refrigeration units.

"Driver convenience items such as walk ramps and liftgates are selling well," Carlson says. "Companies are concerned about being able to keep drivers."

Ace Chicago also has implemented a custom mudflap program with several major fleets. The company stocks mudflaps that have been printed with the fleet's logo and lettering. Mudflaps are shipped to the specified location as the fleet needs them.

Although the parts warehouse has a convenient location, delivering parts to customers is even more convenient.

Ace Chicago serves its market area with two delivery trucks. One covers the north side of the city, and a second vehicle delivers parts to the south side and to nearby cities in Indiana such as Gary and Hammond.

Trucks are loaded daily with a scheduled departure time of 10 am. They deliver parts sold by the company's staff of three outside parts salesmen.

Drivers stay in touch with the warehouse with Nextel cellular phones supplied by the company.

"The trucks also are available for additional deliveries as needed," Goral says. "Our intention is to offer our parts customers same-day service. As such, we sometimes make a second delivery during the day."

The Bolingbrook location is the company's first branch operation. The parts warehouse is linked to the main office via modem and dedicated telephone line.

"That soon will change," Goral says. "We are planning to link our two locations with an Internet connection."

New Computer System Ace Chicago implemented a new computer system about a year ago-including the Solomon software the company uses to manage its two locations.

"It is a simple database package that runs in a Windows environment," Goral says. "We selected it because we were familiar with its basic operations, and our accounting department was pleased with the performance."

The company has about 22 desktop computers and four laptops used by the sales staff. The laptops, equipped with 56k modems and two fax drivers, enable the sales staff to produce sales presentations, generate accurate sales quotations, access inventory status, and obtain up-to-date pricing.

"They are all Compaq computers," Goral says. "We have a lot of confidence in them."

Third Generation Three generations have worked at Ace Chicago Great Dane in the 28 years the company has been in business. Henry Goral and Richard Carlson started the company in 1971. The company's current president, Dennis Goral, is the son of the founder. Henry Goral's grandson Brett joined the company 12 years ago. Four years ago another grandson, Tony, joined the company.

Ace Chicago has always operated one location until now. Although the new parts warehouse in Bolingbrook offers several advantages, Tony Goral offers one pragmatic reason for branching out. As he puts it, "We want to do our best to meet our customers' needs for parts."