1、HEALTH AND ENVIRONMENTAL AFFAIRS DEPARTMENT API PUBLICATION NUMBER 328 JANUARY 1995 Laboratory Evaluation of Candidate Liners for Secondary Containment of Petroleum Products American Petroleum Institute d- Straiqagrw fr Toayi One of the most significant long-term trends affecting the future vitality
2、 of the petroleum industry is the public?s concerns about the environment. Recognizing this trend, API member companies have developed a positive, forward-looking strategy called STEP: Strategies for Today?s Environmental Partnership. This program aims to address public concerns by improving our ind
3、ustry?s environmental, health and safety performance; documenting performance improvements; and communicating them to the public. The foundation of STEP is the API Environmental Mission and Guiding Environmental Principles. API ENVIRONMENTAL MISSION AND GUIDING ENVIRONMENTAL PRINCIPLES The members o
4、f the American Petroleum Institute are dedicated to continuous efforts to improve the compatibility of our operations with the environment while economically developing energy resources and supplying high quality products and services to consumers. The members recognize the importance of efficiently
5、 meeting society?s needs and our responsibility to work with the public, the government, and others to develop and to use natural resources in an environmentally sound manner while protecting the health and safety of our employees and the public. To meet these responsibilities, API members pledge to
6、 manage our businesses according to these principles: To recognize and to respond to community concerns about our raw materials, products and operations. To operate our plants and facilities, and to handle our raw materials and products in a manner that protects the environment, and the safety and h
7、ealth of our employees and the public. To make safety, health and environmental considerations a priority in our planning, and our development of new products and processes. To advise promptly, appropriate officials, employees, customers and the public of information on significant industry-related
8、safety, health and environmental hazards, and to recommend protective measures. To counsel customers, transporters and others in the safe use, transportation and disposal of our raw materials, products and waste materials. To economically develop and produce natural resources and to conserve those r
9、esources by using energy efficiently. To extend knowledge by conducting or supporting research on the safety, health and environmental effects of our raw materials, products, processes and waste materials. To commit to reduce overall emission and waste generation. To work with others to resolve prob
10、lems created by handling and disposal of hazardous substances from our operations. To participate with government and others in creating responsible laws, regulations and standards to safeguard the community, workplace and environment. To promote these principles and practices by sharing experiences
11、 and offering assistance to others who produce, handle, use, transport or dispose of similar raw materials, petroleum products and wastes. API PUBL*328 95 W 0732290 0543840 871 = Laboratory Evaluation of Candidate Liners for Secondary Containment of Petroleum Products Health and Environmental Affair
12、s Department API PUBLICATION NUMBER 328 PREPARED UNDER CONTRACT BY: SAM ALLEN Ethylene interpolymer alloy (EIA) elastomer coated woven polyester fabric; Tri-polymer blend elastomer coated woven polyester fabric; Polyurethane elastomer coated woven polyester fabric; High density polyethylene (HDPE) s
13、heet; Field applied spray-on geotextile coating (polysulfide elastomer on nonwoven needle punched geotextile); Two GCLs having different geotextile backings. The fuel blends tested were: 100% diesel fuel; 100% ethanol; 100% unleaded gasoline (winter blend); 100% methyl tert-butyl ether (MTBE); 10% e
14、thanol90% gasoline mixture (by volume); 15% MTBE/85% gasoline mixture (by volume). ES-1 API PUBLX328 95 0732290 0543848 Oh2 Specifically, the following tasks were undertaken: 0 Rates of vapor permeation were determined for six selected geomembranes exposed to six fuels andor additives. Two of the fu
15、el blends represented high oxygenate formulations. For membrane liners, the mode of transport is vapor permeation or diffusion driven by the concentration gradient which exists across the barrier. Vapor permeation was measured according to ASTM F 739-81 (ASTM, 1981), which is a test method providing
16、 direct, analytical determination of permeating vapor with very high sensitivity. The test was specifically designed to measure the vapor permeation resistance of barrier films and coated fabrics exposed to hazardous chemicals. measuring changes in physical properties as a function of one-sided expo
17、sures of 72 hours and 30 days duration. geosyntheticklay liners (GCLs). For GCLs, the mode of transport is hydraulic conductivity or liquid flow driven by the difference in hydraulic head which exists across the barrier. Each of the six fuels and/or additives was used as a permeant in a modified tri
18、axial cell. manufacture of GCLs were determined by measuring changes in physical properties of the geotextiles as a function of exposure for 72 hours and 30 days duration. O The chemical resistance of six geomembranes to fuels and blends was determined by Liquid conductivity or permeability rates we
19、re determined for two fully hydrated O O The effects of immersion in fuels and additives on the geotextile backings used in Tables ES-1, ES-2 and ES-3 summarize the results of this study. Table ES-1 presents vapor permeation results. Ranking was by material and permeant (1 = lowest steady state perm
20、eation rate), and summed rankings are listed at the bottom of the table, providing a relative indication of overall permeation resistance against the six fuels and/or additives. Table ES-1. Ranked Dermeation results for geomembrane liners Fuel or Blend Polyester EIA coated Tri-polymer Poly-urethane
21、HDPE Poly-sulfide elastomer fabric Blend coated coated fabric spray-on GasolinehTBE Gasoline/ethanol ES-2 API PUBLr328 75 0732270 0543849 TT7 m Table ES-2 presents results of liquid conductivity testing for GCLs. In Table ES-3, ranking for chemical resistance tests was calculated by determining a gr
22、and mean for deviations from 100% of original property retained (1 = lowest mean deviation). This scheme favors those materials which show the least overall change in physical properties. GasolineMTBE With few exceptions, all of the materials tested showed good performance when tested against the si
23、x fuels and blends. The following conclusions were drawn from this study: CHEMICAL RESISTANCE Ranked by overall performance in the physical tests, the tri-polymer blend clearly showed the least overall change after immersion. It was ranked first against each of the six fuels andor blends. The next b
24、est performing product was EIA coated fabric, followed by polyurethane ES-3 API PUBLm328 95 0732290 0543850 710 W coated fabric. HDPE and the polyester elastomer coated fabric showed comparable performance. The polysulfide spray on coated fabric ranked no better than fourth against any fuel or blend
25、. In terms of physical properties, none of the six geomembrane liners were considered to be severely degraded by immersion in the six fuels . Decreases up to 20% in puncture strength were common for coated fabrics; however, the same materials showed consistent increases in tensile strength after one
26、-sided exposure to fuels. Observed increases in tear strength were not considered significant (see Page 4-3). Observed changes in puncture and tensile strength were not large enough to conclude that serviceability or reliability had been compromised. When cut edges were exposed, coated fabrics were
27、found to be subject to wicking into the textile fibers, as evidenced by large weight gains. This observation points to the importance of workmanship in seaming and installation. Cut edges can be protected from exposure to fuel by covering seams with a bonded strip. HDPE showed evidence of slight sof
28、tening and plasticization as a result of fuel absorption into the polymer matrix. Changes in physical properties of up to 20% were observed, with corresponding increases in weight. PERMEATION RESISTANCE OF GEOMEMBRANE LINERS HDPE showed superior overall vapor permeation resistance. The next best per
29、forming product was polyester elastomer-coated fabric, followed by polysulfide- and polyurethane- coated fabrics which showed comparable performance. EIA coated fabric was ranked no better than fourth against any fuel or blend. HDPE and polyester elastomer-coated fabric showed superior permeation re
30、sistance to neat MTBE. HDPEs resistance to diffusion or permeation of fuels was attributed to the fact that as a film, a much thicker polymer barrier is presented to the permeant than exists with any of the elastomer-coated fabrics that were tested. LIQUID CONDUCTIVITY OF GCLS Both GCLs showed very
31、low permeability to both water and fuels. GasolineMTBE blend and diesel fuel had higher permeability rates than water did. Rates for gasolineMTBE blend and diesel fuel were two to five times higher, but still remained in the cdsec range. ES-4 API PUBLr328 75 0732290 0543853 657 GCL GEOTEXTILE BACKIN
32、GS Effects on the physical properties of geotextile backings that were exposed to fuels were not considered significant. PERMEATION TESTING It was concluded that the analytical vapor permeation test (ASTM F 739-81 (ASTM, 1994) is highly appropriate for determining diffusion rates for fuel containmen
33、t applications. However, poor correlation with the commonly used gravimetric test (ASTM E 96-93 (ASTM, 1993) was observed. It is strongly recommended that the analytical test, ASTM F 739-81, be considered as the preferred method for measuring diffusion rates and breakthrough times for fuel exposure
34、to geomembranes. It is also recommended that permeation resistance for synthetic geomembrane liners not be specified in terms of hydraulic conductivity units (cdsec), since the mode of transfer across the barrier is by vapor diffusion rather than liquid transport. GENERAL CONCLUSIONS AND RECOMMENDAT
35、IONS Further study is recommended to develop design and product selection guidelines for release prevention barrier and dike containment applications. Use of these products for petroleum containment applications is expected to increase, and a comprehensive program to develop design parameters and se
36、lection criteria would meet a pressing need that exists in the petroleum industry. The overall conclusion drawn from this study is that each of these materials can offer good- to-excellent performance in applications where contact with fuels may occur, assuming that proper design practices are used.
37、 The user should consider requirements for permeation resistance together with other factors in selecting the liner material which best suits each situation. ES-5 API PUBLx328 95 0732290 0543852 593 Section 1 INTRODUCTION This report documents a laboratory study of geosynthetic liner materials propo
38、sed for use in the secondary containment of petroleum fuels and fuel blends in aboveground storage tanks (ASTS). Six geosynthetic membrane liners and two geosynthetic clay liners were tested to determine vapor permeation resistance (membrane liners) and hydraulic conductivity (clay liners), and to m
39、easure changes in physical properties after immersion in fuels and blends representative of those stored in AST facilities. A previous study completed in 1992 (TRI, 1993) provided an assessment of tankfield dike lining materials and methods for secondary containment of AST facilities. The direct com
40、parative data needed to evaluate the various kinds of synthetic liners available on the market was lacking, and the present study was initiated to meet this need. The resulting performance data would be useful to potential users of synthetic liner products for fuel containment applications, such as
41、release prevention barriers and the lining of dikefields. The selection of liner products, fuels and blends was made by the API Liner Study Workgroup which provided oversight to the development and execution of the project. The matrix of fuel exposure conditions and testing procedures was recommende
42、d by the contractor based on methods used to characterize coated fabrics and films within the geosynthetics and waste containment industry, with approval by the Workgroup. Tests were selected which are designed to be used with each type of material under consideration (e.g., coated fabric vs. thermo
43、plastic film - HDPE). OBJECTIVES AND PROJECT OVERVIEW The objective of this test program was to provide comparative data on vapor permeation, chemical resistance, liquid conductivity and other physical properties of geosynthetic membrane liners and GCLs as a function of controlled exposure to fuels
44、and blends. The term release prevention barrier includes steel bottoms, synthetic materials, clay liners and all other barriers or combinations of barriers placed in the bottom of, or under, an aboveground storage tank, which have the functions of: (1) preventing the escape of contained material, an
45、d (2) containing or channeling released material for leak detection. 1-1 API PUBL+328 95 0732290 0543853 42T D The liner materials tested included: Polyester elastomer coated woven polyester fabric; Ethylene interpolymer alloy (EIA) elastomer coated woven polyester fabric; Tri-polymer blend elastome
46、r coated woven polyester fabric; Polyurethane elastomer coated woven polyester fabric; High density polyethylene (HDPE) sheet; Field applied spray-on geotextile coating (polysulfide elastomer on nonwoven needle punched geotextile); and Two GCLs having different geotextile backings. The fuel blends t
47、ested were: 100% diesel fuel; 100% ethanol; 100% unleaded gasoline (winter blend); 100% methyl tert-butyl ether (MTBE); 10% ethanol/90% gasoline mixture (by volume); and 15% MTBE/85% gasoline mixture (by volume). Specifically, the following tasks were undertaken: Rates of vapor permeation were deter
48、mined for six selected geomembranes exposed to six fuels andor additives. Two of the fuel blends represented high oxygenate formulations. For membrane liners, the mode of transport is vapor permeation or diffusion driven by the concentration gradient which exists across the barrier. Vapor permeation
49、 was measured according to ASTM F 739-81 (ASTM, 1994), which is a test method providing direct, analytical determination of permeating vapor with very high sensitivity. The test was specifically designed to measure the vapor permeation resistance of barrier films and coated fabrics exposed to hazardous chemicals. The chemical resistance of six geomembranes to fuels and blends was determined by measuring changes in physical properties as a function of one-sided exposures of 72 hours and 30 days duration. Liquid conductivity or permeability rates were determined for two fully h
