Dr. Jude Francis Parsons Engineering Science 199 S. Los Robles Avenue Pasadena, CA

Transcription

1 SHELF LIFE SPECIFICATION FOR HAZARDOUS MATERIALS : PAINTS, SEALANTS AND ADHESIVES Dr. Jude Francis Parsons Engineering Science 199 S. Los Robles Avenue Pasadena, CA The Navy and the other services within the Department of Defense use numerous hazardous materials in their day to day operations including paints, sealants, adhesives, petroleum, oils, lubricants, and other chemicals and miscellaneous materials. The management of these hazardous materials is critically dependent on the shelflife code (defined in the ShelfLife Item Management Manual, DoD ) assigned to these materials. The shelflife of a material is dependent on several factors such as the product composition, product specification requirements, intrinsic degradation rate of the material (typically dependent on temperature), storage conditions, and packaging. The management of hazardous materials is an issue of critical importance because once a material s shelf iife has expired, it becomes a hazardous waste which would be expensive to dispose of. Furthermore, new substitute material would need to be purchased. Parsons Engineering Science (Parsons ES), a full service environmental consulting firm, is under contract with the Naval Facilities Engineering Services Center and the Naval Supply Systems Command to determine the most appropriate shelf life codes for commonly used hazardous material procured by the US Navy. Currently used shelf life codes tend to be too conservative which results in early disposal of useful material or increased quality testing and analysis costs. The objective of this study is to review the product formulation, examine the chemistry and packaging of one hundred and sixty (160) specific commodities commonly procured by the Navy to provide a technical basis for shelf life code specification. The Navy s primary goal with this project is pollution prevention. The Parsons ES project team comprised of senior chemists and chemical engineers. For each material, numerous data sources are employed, such as, MSDS, technical data sheets, manufacturer data, commercial and open literature, DOD material test data, and military and commercial specifications. Each project team member is assigned individual materials and their recommendations undergo a peer review process. The project team scrutinizes the recommendation before it is finalized to ensure that it is appropriate and in keeping with the goals of this project. The report on each material includes a section on Specification Requirements, Material Description, Intended Use, Degradation Mode, Description of Shelf Life, Recommendation, and Quality Testing Data. Paints, sealants and adhesives (PSAs) are typically a family of materials that are similar in composition and contain pigments, resins, solvents, fillers, and other additives. These materials typically cure after application on a substrate by exposure to air or moisture to form durable surface coatings that serve to protect the substrate or for use in bonding applications. These m:\jfrancis\word6\f-abs. doc July 6,

2 ~ time materials can be one-part or two-part compounds supplied in kits, and are typically short shelf life items (6 months to 24 months). These materials can be packaged in a multitude of different ways including, aerosol cans, plastic tubes, small coated metal cans (1 qt., 2 qt. etc.) and metal pails (1 gal, 5 gal, etc.). They tend to degrade rapidly during storage in the packaging, and can cause a great deal of waste disposal problems. Most of these materials are in the 8010, 8030 and 8040 Federal Supply Classes (FSC). This paper will discuss the degradation modes of these materials (layer separation, premature curing, propellant loss, etc.), packaging, storage conditions, and the problems associated with determining their appropriate shelf life. The goal of this project is to use a technological and scientific basis for assigning a shelflife code for a given hazardous material with a motivation of pollution prevention, that is, any shelf life codes that can be extended will decrease disposal costs or quality testing costs, and decrease pollution. Although, it is known that the shelf life code of any material cannot be derived from any scientific formulas, the best shelf life recommendations can be made based on a technical evaluation of the degradation mode of the material, its packaging, and the engineering judgement of persons knowledgeable about chemicals. An assumption made in this study is that most materials are stored indoors in non-temperature controlled warehouses. Since the military depots are located in several different areas with different climates, extremes in climate had to be factored into. our assumptions. One of the problems associated with appropriate shelf life code determination is the frequent changes in product formulation that occur as a result of DOD specification changes, manufacturer changes, and technology improvements. New product formulations require new shelf life assessments. This is another reason why manufacturers tend to recommend ultraconservative shelf life periods (often called guarantee shelf life period) for their products. The manufacturers typically do not have a pollution prevention or financial motive to determine appropriate shelf life periods for their materials or find recyclable uses for aged materials. Thus far, one hundred and fifty six (156) materials have been assigned for study. Final recommendations have been made for 153 materials. Of these, 81 shelf life codes were lengthened, 63 were unchanged and 9 were reduced. A total of 50 NSNs are classified as belonging to the group of Paints, Sealants and Adhesives. Of these, 19 shelf life codes were increased by about % (in time period) and 29 shelf life codes stayed the same and about 2 codes were reduced. This presentation will discuss the unique nature of the degradation of paints, sealants and adhesives, and the criteria for determining their appropriate shelf life. This paper makes a list of recommendations to help develop a better P2-oriented management system for hazardous materials such as paints, sealants and adhesives. The recommendations include: 0 Improvement in storage conditions, where, certain PSA items that are sensitive to storage are identified and are recommended for air conditioned storage areas in depots. The addition of small air conditioned areas in depots can ensure that these PSAs are not exposed to occasional diurnal temperature fluctuations above 90 F. Since every 10 C rise in temperature can actually cut the shelf life in one-half, this option could be viable with a reasonable pay back for the investment. Include regulatory directivedincentives or specification requirements for manufacturers to supply additional shelf life information for the DOD customer. Current specifications require m:\jfiancis\word6\f-abs. doc July 6,

3 manufacturers to test and certie minimum shelf life periods (6 months, 12 months, etc.) at specific storage conditions. An additional condition could be added to the specification which requires that information be provided on whether that same batch passed quality testing after double that time period. However, this does not have to be mandatory for Qualified Product List (QPL) approval. The selective assignment of NSN numbers for materials to ensure that materials of similar shelflife periods have the same NSNs. One common problem is that one specification (e.g. MIL-C-16173E) that has 2 classes, 2 types, and 5 grades of materials. In such a case, all materials of this specification should not be assigned one shelf life code because then one is forced to set the code based on the most sensitive material s shelflife. Another problem is when packaging of the material is shelf life-determining, and different packaging sizes including aerosol and non-aerosols are lumped under one NSN, one encounters a similar situation. One viable approach for this problem is that aerosols and non-aerosols always be assigned different NSNs even if they are otherwise the same product. Making the DOD s QSL and Air Force s SLED databases more PZoriented tools, and thus help in improved shelf life specification. This can be achieved by including date of manufacture of batch, mode of failure, etc. If this can be achieved, it is likely that manufacturers themselves could become interested in the QSL and SLED data. Finally, when the recommendations from this study are implemented by the Navy, the reduction in waste and disposal costs, as well as the reduction in new material acquisition costs is expected to be sigmficant. m:\j fiancis\word6\shlf-abs. doc July 6,

4 Shelf Life Specification for Hazardous Materials Shelf Life Specification for Hazardous Materials - Paints, Sealants, and Adhesives Project Sponsors. Naval Facilities Engineering Services Center Naval Supply Systems Command Jude T. Francis Parsons Engineering Science 199 Los Robles Avenue Pasadena. Califomia I Project Goals Review current shelf life codes and Recommend most appropriate codes for 160 hazardous materials commonly procured by the Navy. High volume and high disposal cost materials are. targeted Goal is Pollution Prevention Lengthening shelf life codes can Reduce disposal costs. Reduce new material acquisition costs * Reduce testing and analysis costs Project Approach Project team comprised of senior chemical engineers and chemists Each team member was assigned NSNs. Technical evaluation of shelf life. t Final recommendation accepted afler peer review Recommendations emphasize conservativeness Product quality on delivery is vital

5 Methodology Manufacturer Discussions MSDS and Product literature review Product Formulation studied Degradation Chemistry Assumptions needed. Storage conditions - non-temperature controlled, covered warehouses. Variability in climates at depot locations Project Data Sources =.Hazardous Material Information System (HMIS) CD-ROM FedLog database DOD's Quality Status List (QSL) Air Fxce's Shelf Life Extension Database, SLED Manufacturer datalmsdsslproduct Data sheets Military Specifications Specification Writers = Technical Journals/Other specialists Report Structure Summary Heading = Specification Requirements Material Description Intended Use Degradation Modes Discussion of Shelf Life Recommendation = Comments QSUSLED Data Table Bibliography Report Details Final Report will contain final recommendations for all NSNs Each Data Report is about 3-5 pages. Typically NSNs of same specification grouped together in one report Report considered a "working document". Identified any observed discrepancies with HMIS/Fedlog/QSL databases. Alternative uses of shelf life expired material Alternative products with less hazardous material

6 Paints, Sealants and Adhesives (PSAs) 9 FSCs 8010,8030,8040 PSAs typically contain resins, pigments, solvents, fillers and other additives (e.g. catalysts,..) Short shelf life items (6 months to 24 months) 1 -part or 2-part compounds Variety of packaging - tubes, cans, pails, aerosol Definition and Types of Shelf Life 9 Actual Shelf Life - typical time period that material is usable for intended application or in compliance with specification Shelf Life Code assigned by DO0 as defined in Shelf Life Item Management Manual ( ~). Type I - Nonextendible, Dispose on expiry Type II - Extendible, Retest at end of period m Warranty Shelf Life - manufacturer guaranteed period for which the product will be in compliance with specification Assigning Shelf Life Code Graph Showing Failures vs Time Shelf Life Determining Factors I 1ooW 50% 0% % Cumulative Failures A C B A Storage Time (Months) A A = Adual Shelf Life B = Shelf Life Code C 5 Warranty SheH LE m = Shelf Life of any material is dependent on several parameters. Storage conditions ' Every 10 deg C increase can halve shelf life! Chemical Composition Specification Requirements Use or Application Intrinsic degradation rate of material. Packaging

7 Product Life Flow Chart + :EzJ Degradation Modes - OFFSPEC WASTE 4 Shelf Life - Paints, Sealants and Adhesives Degradation Modes * Layer separation Premature curing t Reaction with Moisture or Oxygen in air Reaction with Moisture (or additive) in material t Propellant loss = Identify Critical Degradation Mode Estimate actual shelf life Finally, Recommend shelf life code Paints, Sealants, and Adhesives Sample of Shelf Life Recommendations Problems Encountered Uncertainty in storage conditions makes shelf life code recommendation to be conservative Shelf Life Code recommended is best approximation Manufacturers do not have P2 or financial motive to provide long shelf life materials Product composition changes frequently with PSAs. Changing technology, equipment, specifications Proprietary nature of chemical composition of products (additives) adds uncertainty to recommendation

8 Recommendations = Store certain PSA items in airconditioned areas in depots. 10 deg C decrease can double shelf life Include requirements in specification for more shelf life testing data from manufacturers Need to indicate on HMlS if shelf life code is based on date of manufacture or date of shipment = For some specificationslmaterials. Avoid assigning the same shelf life code or same NSN to all types, grades of material, e.g. aerosol and non-aerosol versions Recommendations Make DOD's QSL and Air Force's SLED databases more P2-oriented tools Track PSAs in Navy's QSL Improve PQDRs system for failures in QSUSLED Add shelf life codes for Type II, extendable; 4A = 15 months, 5A = 21 months NSN Data Reports could go on a on-line database for modem access c- W 0 Paints, Sealants, and Adhesives Status Number of PSA Commodities = 50 Shelf Life Code Unchanged = 29. Shelf Life Code Lengthened = 19. Shelf Life Code Reduced = 2 Increased 38% Increased 87% Status Summary POLS and Chemicals Increased 55% 2-34% Unchanged Unchanged POLS Chemicals Unchanged 58%

9 Overall Project Status. Commodities Assigned for Study = 156 Final Recommendations = 153 Shelf Life Code Lengthened = 81 Shelf Life Code Unchanged = 63. Shelf Life Code Reduced = 9 Increased 53% Conclusion - Final Report will recommend appropriate shelf life codes for 160 NSNs + Found room to lengthen shelf life codes for several commodities by about % Will achieve goal of pollution prevention. Propose Economic evaluation. DWDGSC databases + Estimate savings due to increased shelf life Unchanged 41%

10