STAFF REPORT

AIRTIGHT

EFFICIENCY

Tobacco companies aside, the voracious cigarette beetle (Lasioderma serricorne) has two archenemies: phosphine fumigation and L&L Coatings. The former has proven itself as one of the most effective means available by which to eliminate the cigarette beetle. The latter, for more that 28 years, has been helping to ensure the continued elimination of the cigarette beetle by providing gas-tight capabilities on difficult or impossible to fumigate structures, which in turn keeps the phosphine fumigation around for a longer duration.

It is well-known throughout the industry that cigarette beetle control is one of the most essential steps in preventing damage to stored tobacco and that the most cost effective method of cigarette beetle control is phosphine fumigation. However, even though many companies use this method to maintain their tobacco, money is still lost for the simple reason that if a new warehouse is not gas-tight, the gas soon escapes.

L&L's Permanent Fumigation Containment System was developed to solve this problem; it creates gas-tight structures and reduces the cost of fumigants by maintaining gas concentrations longer. It also ensures a clean kill on the adults, pupa, and egg stages of the beetle.

"The Containment System provides the further benefit of covering the EPA's proposed risk mitigation measures concerning the use of aluminum and magnesium phosphine as a fumigant in tobacco storage facilities," said Terry Linville, president of L&L Coatings. Among the measures pertaining to the tobacco industry are:

 RMM7 - Proposal to require two man operation of any activity that would involve entry into a fumigated structure. Application of the L&L

Permanent Fumigation Containment System eliminates the #1 cause for re-entry: having to re-administer additional phosphine due to gas loss through an unsealed structure.

 RMM8 - Establish 500-foot buffer zone and restricted are around all fumigated structures. A warehouse properly sealed with L&L's Permanent Fumigation Containment System would make a 500-foot buffer zone unnecessary.

 RMM10 - Required Seal/Leak testing for fumigation structures. Tobacco storage warehouses that have been sealed with the L&L Permanent Fumigation Containment System average only 46.95 CFM air-loss when exposed to 2,000 CFM air pressure during fan tests.

 RMM14 - Monitoring methods to minimize exposure. The EPA proposes an incredibly low concentration level of 0.03 PPM, a level so low that there are no instruments available that can monitor phosphine at those low concentrations. It has been noted that there is evidence that the human sense of smell can detect the "garlic odor" added to the phosphine at levels around 0.02 PPM. The EPA goes on to say, "under no circumstances should a person consider smell as a monitoring option in lieu of device monitoring."

Last year, L&L Coatings took on its largest project ever, 44 warehouses that had a total of 56,000,000 cubic feet of airspace. By the time the job was completed, 325 miles of reinforced seams of corrugated metal had been sealed off with the L&L's laminated fabric, which allows the seams to contract and expand freely. Linville notes that the Containment System can be customized to storage facilities smaller or larger in scale than the one listed above. And the time it takes to complete a job varies according to the size of the overall operation. For example, the above project took a little over two years.

Initially, a facility inspection takes place from the ground up. All areas that are not air-tight are identified, with special attention being paid to transition areas such as foundation to metal panel

Above left: The L&L Permanent Fumigation Containment System bridges every seam, transition, conduit or water pipe penetration and seals fasteners and all other potential leak surfaces. Above right: A wall-to-roof transition area of an unsealed tobacco storage warehouse. During fumigation operations, the phosphine gas will escape from every hole, crack, seam and penetration.

areas, metal panel to soffit, and metal panel to fire walls, skylights and roof penetrations. Also, missing or damaged building components are noted, as well as deteriorated areas of the building. Specifications then come into the equation. A detailed spec is generated.

Nearly a quarter of a century of solving problems in sealing tobacco warehouses gives L&L the know-how to address typical recurring sealing problems. The company can find the most cost-effective solutions for hard-to-seal surfaces unique to a customer's facility, and it can correct these areas and ultimately provide a gas-tight building.

Before any work takes place, a complete list of materials and costs is provided in writing. The company also provides a list of contractors who have the training and practical experience in installing the L&L Permanent Fumigation Containment System.

One such contractor is Davis and Associates of Vicksburg, Mississippi, which has been installing L&L's Containment System for over fifteen years. Bill Davis, Davis and Associates' president, said, "When a company has tried everything imaginable to solve an airflow problem and hasn't made any headway, that's when they turn to L&L's Permanent Fumigation Containment System - and it works. It always works."

WARNING SIGNS IN THE WAREHOUSE

  • Storage of tobacco demands that fumigation be administered to reduce the loss and contamination of tobacco due to cigarette beetles and other pests.
  • The fumigant, in order to be effective, must contain a certain concentration (PPM) over a determined period of time.
  • A typical tobacco storage warehouse is a metal building. Metal buildings are usually constructed by fastening 24-inch-wide metal panels to the structure's internal frame. Where each of these seams overlap, a seam is created. Over time and die to expansion

and contraction, these seams tend to open, which breaks the temporary seal installed during construction.

  • The average-sized tobacco storage warehouse has approximately 36, 500 feet of seams. If the airspace between the panels were only 1/32 of and inch wide, the net effect is an efficient ventilation system whose total open surface area is 95 square feet - an opening large enough to drive a tractor-trailer through. Thus, the extremely flexible coating from L&L, when coupled with a bridging fabric covering the seams, creates an air-tight seal.

KEY MATERIALS EMPLOYED BY L&L

L&L 300 Mastic - A high-build, waterborne, elastomeric barrier coating. Its unique blend of premium acrylic resins and pigments combine to form a durable, mildew-resistant film with outstanding adhesion and flexibility. L&L 300 is a breathing mastic that allows damaging substrate moisture to escape while protecting against ultraviolet rays, water, and air-flow intrusion.

L&L 163 Primer/Sealer - A multifunction, elastomeric, waterborne, acrylic primer/sealer. It is manufactured to provide optimum adhesion

and flexibility. The substance penetrates and seals, leaving an adhesive "tacky" film that promotes maximum bond with the substrate and subsequent coat. Seals, joints, seams, cracks, roof and wall penetrations and skylight perimeters can be reinforced with L&L polyester mat, Polyester mesh, or Dynel cloth.

L&L Tri-Clad Polyester Tape - A pressure-sensitive tape used to bridge seams in roofing insulation and construction materials. This material creates a water-tight seal, eliminating damage due to roof leakage. L&L Tri-Clad Polyester Tape is a vapor barrier

that makes it an excellent choice for permanent sealing projects in controlled-atmosphere environments such as those employed in fumigation containment, air-flow management, coolers and freezers.

L&L Polyester Reinforcing Fabric - Made of stitchbonded polyester, this is considered one of the strongest and most versatile cold roofing polyester materials available for use in reinforcement systems. Stitch-bonding offers a combination of high strength properties with good elongation providing an excellent