Liquid Boot
Using Vapor Intrusion Subslab Barriers Rob Carvahlo and Amanda Petrocelli EAI, Inc.
LINING TECHNOLOGIES
|
REMEDIATION TECHNOLOGIES
|
DRILLING SYSTEMS
|
BUILDING ENVELOPE
|
CONTRACTING SERVICES
GAS VAPOR MITIGATION SYSTEMS FOR PROTECTION AGAINST VAPOR INTRUSION Amanda Petrocelli [email protected]
Robert Carvalho [email protected] 201.395.0010 October 11, 2011
2
GAS VAPOR MITIGATION SYSTEMS
Agenda Gas Vapor Mitigation Options Chemical/Physical Properties Diffusion Testing
CETCO Offerings Gas Vapor Barrier Systems Gas Venting Systems
Quality Control Case Studies by EAI
3
GAS VAPOR MITIGATION SYSTEMS
The Risk: Vapor Intrusion Vapor intrusion is the migration of subsurface chemical vapors into overlying structures. Vapors may include: Volatile organic compounds (VOCs) Semi-volatile organic compounds Inorganics (i.e.. mercury, hydrogen sulfide, etc.) Methane Radon Naturally-occurring / man-made contaminants
Vapor intrusion and indoor air risk occurs when you have: A source An inhabited building A pathway from the source to the inhabitants
Vapor intrusion has become a significant environmental issue for regulators, industry leaders, and concerned residents nationwide.
4
GAS VAPOR MITIGATION SYSTEMS
The Risk: Vapor Intrusion “Current lack of knowledge about indoor air issues and evaluation techniques may oversimplify the problem and may cause air quality investigations and subsequent risk assessments to understate or overstate the problem. Indoor air quality is overlooked in many environmental site investigation and soil or groundwater plume contamination scenarios. Lack of knowledge regarding indoor air quality issues and cost considerations tend to contribute to the omission of indoor air sampling and evaluation.” – ITRC
CETCO offers:
5
Solutions for various site conditions, backed by extensive track record/case history Experienced technical managers with knowledge on current industry trends Technical and design assistance for gas vapor membrane and venting systems World-class Research & Development facility Design-build capabilities
GAS VAPOR MITIGATION SYSTEMS
GAS VAPOR MITIGATION OPTIONS
6
GAS VAPOR MITIGATION SYSTEMS
Two Types of Gas Vapor Barriers (per ITRC Guidance) Gas vapor barrier options include:
Sheet-applied, batten and welded 60 mil - HDPE
7
GAS VAPOR MITIGATION SYSTEMS
Spray-Applied Membranes 60 mil - Liquid Boot®
Physical Properties of Liquid Boot® (spray-applied) Physical Property
*
* * *
Test Method
Result
ASTM D6392
Passed
ASTM D4068-88
Passed
City of Los Angeles
Passed
ASTM D1693-78
Passed
Soil Burial
ASTM E154-88
Passed
Elongation
ASTM D412
1,332% - Ø reinforcement, 90% recovery
Tensile Strength
ASTM D412
58 p.s.i. without reinforcement
Tensile Bond Strength to Concrete
ASTM D413
2,707 lbs/ft2 uplift force
Water Vapor Permeability
ASTM E96
0.24 perms
Water Vapor Transmission
ASTM E96
0.10 grains/h-ft2
Bonded Seam Strength Tests
Heat Aging- average tensile strength change, average tensile stress change, average elongation change, bonded seams
Dead Load Seam Strength
Environmental Stress-Cracking
* City of Los Angeles approval for 60-mil Liquid Boot® Gas Vapor Barrier
8
GAS VAPOR MITIGATION SYSTEMS
Chemical Properties of Liquid Boot® (spray-applied)
* * *
Chemical Property
Test Method
Result
Acid Exposure (10% H2SO4 for 90 days)
ASTM D543
Less than 1% weight change
Diesel (1000 mg/l), Ethylbenzene (1000 mg/l), Naphthalene (5000 mg/l) and Acetone (500 mg/l) Exposure for 7 days
ASTM D543
Less than 1% weight change, Less than 1% tensile strength change
Radon Permeability
Tested by US Dept. of Energy
Zero permeability to Radon (222Rn)
Micro Organism Resistance (Soil Burial)
ASTM D4068-88
Passed*
Methane Permeability
ASTM 1434-82
Passed*
Oil Resistance Test- average weight change, average tensile strength change, average tensile stress change, average elongation change, bonded seams, methane permeability
ASTM D543-87
Passed*
PCE Diffusion Coefficient
Tested at 6,000 mg/m3
2.74 x 10-14 m2/sec
TCE Diffusion Coefficient
mg/m3
8.04 x 10-14 m2/sec
Tested at 43,000 mg/m3
2.90 x 10-11 m2/sec
Benzene Diffusion Coefficient
Tested at 20,000
* City of Los Angeles approval for 60-mil Liquid Boot® Gas Vapor Barrier
9
GAS VAPOR MITIGATION SYSTEMS
Membrane Diffusion Test – Modified ASTM E96 The diagram illustrates how the diffusion coefficients on the Liquid Boot membrane for PCE, TCE and Benzene were determined CETCO R&D facility is capable of performing these tests
10
GAS VAPOR MITIGATION SYSTEMS
Fick’s Law Applying diffusion test data into the Fick’s Law equation results in the diffusion coefficient:
E= A(Csource - Cg0)Dczeff / Lcz where
11
E
=
Rate of mass transfer, g/s
A
=
Cross-sectional area through which vapors pass, cm2
Csource
=
Vapor concentration within the capillary zone, g/cm3-v
Cg0
=
A known vapor concentration at the top of the capillary zone, g/cm3-v (Cg0 is assumed to be zero as diffusion proceeds upward)
Dczeff
=
Effective diffusion coefficient across the capillary zone, cm2/s
Lcz
=
Thickness of capillary zone, cm
GAS VAPOR MITIGATION SYSTEMS
Diffusion Test Results Summary
12
Test Conditions
Average Solvent Diffusion Rate
Membrane Area
Membrane Thickness
Calculated Diffusion Coefficient
PCE Solvent @ 6,000 mg/m3
0.12 mg/day
1.45 x 10-2 m2
1.68 x 10-3 m
2.74 x 10-14 m2/sec
TCE Solvent @ 20,000 mg/m3
1.22 mg/day
1.48 x 10-2 m2
1.57 x 10-3 m
8.04 x 10-14 m2/sec
Benzene @ 13,000 mg/m3
1.4 mg/day
1.48 x 10-2 m2
1.57 x 10-3 m
1.4 x 10-14 m2/sec
Benzene @ 136,000 mg/m3
19 mg/day
1.48 x 10-2 m2
1.57 x 10-3 m
1.9 x 10-13 m2/sec
GAS VAPOR MITIGATION SYSTEMS
Venting Systems (Used In Conjunction with a Gas Vapor Barrier per ITRC Guidance) Passive Venting
Rely on nature pressure differentials to vent the subsurface gas Can be designed to be converted to active, if needed, to reduce vapor concentrations Should be properly designed to allow adequate flow of vapors Evaluation of air flow should be conducted
13
GAS VAPOR MITIGATION SYSTEMS
Active Venting Use of mechanical means to alter and maintain pressure gradients & redirect subsurface gas flow Major system components generally include gas extraction wells and piping, vacuum blowers, and gas/vapor treatment or reuse systems
CETCO SYSTEM OFFERINGS
14
GAS VAPOR MITIGATION SYSTEMS
CETCO System Offerings
Liquid Boot® Gas Vapor Barrier System
15
Liquid Boot® Plus
Coreflex®
High-Performance Gas Vapor Barrier System
Methane Barrier & Waterproofing System
GAS VAPOR MITIGATION SYSTEMS
GeoVent® Gas Venting System
LIQUID BOOT® GAS VAPOR BARRIER SYSTEM
16
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® System Description: Liquid Boot® is a cold, spray-applied membrane that acts as a gas vapor barrier and damp-proof membrane.
Typical Uses: Applied under slab and on below grade vertical walls as a gas vapor barrier to minimize vapor and nuisance water (non-hydrostatic conditions) migration into buildings Ideal for methane migration control Concrete water tank and reservoirs liner to prevent water seepage into concrete Applied as a liner to concrete canals for rehabilitation
Agency Approvals: City of Los Angeles Research Report # 24860 Approved for Liquid Boot®
Membrane for Gas Barrier
County of Los Angeles Department of Public Works Approved for “Liquid Boot® Application
as a Methane Gas Barrier”
NSF International-NSF/61
Approved for “Potable Water Tank Liner” for tanks >300,000 gallons
17
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® System Components and Features: GeoVentTM Gas Venting System Low profile; no trenching required
Liquid Boot® BaseFabric T-40/T-60 (fabric selection depends on site conditions) Heat bonded non-woven geotextile
Liquid Boot® Two component spray applied membrane (60 mils typical) Water based - No VOCs, odorless Bonds to most surfaces – eases detailing Seamless - eliminating membrane failures Rapid curing - reducing construction time High strength and elongation – durable
Liquid Boot® UltraShield Series Protection Course G Series - Needle-punched, nonwoven geotextile P Series - HDPE Polyethylene geomembrane Adheres to the underslab providing superior tensile strength
18
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® PILE CAPS AND FOOTINGS
PENETRATIONS
19
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® VERTICAL SURFACE ATTACHMENTS
20
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® TYPICAL SYSTEM INSTALLATION
1. Liquid Boot® applied to BaseFabric
21
GAS VAPOR MITIGATION SYSTEMS
2. Penetrations Detailed
3. UltraShield Protection Fabric
LIQUID BOOT® PLUS HIGH-PERFORMANCE GAS VAPOR BARRIER SYSTEM
22
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® Plus System Description: The Liquid Boot® Plus Gas Vapor Barrier system is a multi-layer and high-performance, cold spray-applied membrane that acts as a gas vapor barrier and damp-proof membrane.
Typical Uses: Installed under slab and on below grade vertical walls as a gas vapor barrier to minimize vapor and nuisance water (non-hydrostatic conditions) migration into buildings Ideal for applications with chlorinated solvents, BTEX and other PAHs
Agency Approvals: City of Los Angeles Research Report # 24860
Approved for Liquid Boot® Membrane for Gas Barrier County of Los Angeles Department of Public Works
Approved for “Liquid Boot® Application as a Methane Gas Barrier”
23
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® Plus System Components and Features: GeoVent® Gas Venting System
Low profile; no trenching required Liquid Boot® VI-20 Geomembrane
EVOH composite geomembrane - 20x lower VOC diffusion than 80 mil HDPE Liquid Boot® VI-20 Detailing Fabric Liquid Boot®
Two component spray applied membrane (60 mils typical) Water based - No VOCs, odorless Bonds to most surfaces – eases detailing Seamless - eliminating membrane failures Rapid curing - reducing construction time High strength and elongation - durable Liquid Boot® UltraShield Series Protection Course
G Series - Needle-punched, nonwoven geotextile P Series - HDPE Polyethylene geomembrane Adheres to the underslab providing superior tensile strength
24
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® VI-20 Geomembrane Tested by Dr. Kerry Rowe, Queens University, Ontario
Author of the POLLUTE model Well-known in geosynthetics industry Determined upper bound partition and diffusion coefficients Aqueous phase diffusion coefficient of co-extruded geomembrane
25
Liquid Boot® VI-20
80-mil HDPE
Contaminant
Diffusion Coefficient (m2/s)
Diffusion Coefficient (m2/s)
Benzene
9.0 x 10-15
3.5 x 10-13
Ethyl Benzene
8.0 x 10-15
1.8 x 10-13
Toluene
8.5 x 10-15
3.0 x 10-13
O-Xylene
7.5 x 10-15
1.5 x 10-13
GAS VAPOR MITIGATION SYSTEMS
EVOH Geomembrane Technology Liquid Boot® VI-20 geomembrane is a layer of EVOH between two layers of polyethylene. EVOH is a copolymer of:
Polyethylene (extrudes easily and improves bonding) Polyvinyl Alcohol and Ethylene Vinyl Alcohol (provides gas barrier)
Major applications for EVOH is in automotive fuel systems to control emissions of hydrocarbons The use of EVOH in a co-extrusion blow-molded tank with molecular weight HDPE originated in the US in response to mandates of VOC emissions reductions by the US EPA and the CA Air Resources Board (CARB) and is has been in widespread use globally for more than 15 years.
26
GAS VAPOR MITIGATION SYSTEMS
EVOH Geomembrane Technology Development started in 1989 in response to EPA and CARB mandates Emissions regulations have progressively become tighter each decade EVOH became barrier of choice due to VOC barrier properties Emissions through tank shell are
LINING TECHNOLOGIES
|
REMEDIATION TECHNOLOGIES
|
DRILLING SYSTEMS
|
BUILDING ENVELOPE
|
CONTRACTING SERVICES
GAS VAPOR MITIGATION SYSTEMS FOR PROTECTION AGAINST VAPOR INTRUSION Amanda Petrocelli [email protected]
Robert Carvalho [email protected] 201.395.0010 October 11, 2011
2
GAS VAPOR MITIGATION SYSTEMS
Agenda Gas Vapor Mitigation Options Chemical/Physical Properties Diffusion Testing
CETCO Offerings Gas Vapor Barrier Systems Gas Venting Systems
Quality Control Case Studies by EAI
3
GAS VAPOR MITIGATION SYSTEMS
The Risk: Vapor Intrusion Vapor intrusion is the migration of subsurface chemical vapors into overlying structures. Vapors may include: Volatile organic compounds (VOCs) Semi-volatile organic compounds Inorganics (i.e.. mercury, hydrogen sulfide, etc.) Methane Radon Naturally-occurring / man-made contaminants
Vapor intrusion and indoor air risk occurs when you have: A source An inhabited building A pathway from the source to the inhabitants
Vapor intrusion has become a significant environmental issue for regulators, industry leaders, and concerned residents nationwide.
4
GAS VAPOR MITIGATION SYSTEMS
The Risk: Vapor Intrusion “Current lack of knowledge about indoor air issues and evaluation techniques may oversimplify the problem and may cause air quality investigations and subsequent risk assessments to understate or overstate the problem. Indoor air quality is overlooked in many environmental site investigation and soil or groundwater plume contamination scenarios. Lack of knowledge regarding indoor air quality issues and cost considerations tend to contribute to the omission of indoor air sampling and evaluation.” – ITRC
CETCO offers:
5
Solutions for various site conditions, backed by extensive track record/case history Experienced technical managers with knowledge on current industry trends Technical and design assistance for gas vapor membrane and venting systems World-class Research & Development facility Design-build capabilities
GAS VAPOR MITIGATION SYSTEMS
GAS VAPOR MITIGATION OPTIONS
6
GAS VAPOR MITIGATION SYSTEMS
Two Types of Gas Vapor Barriers (per ITRC Guidance) Gas vapor barrier options include:
Sheet-applied, batten and welded 60 mil - HDPE
7
GAS VAPOR MITIGATION SYSTEMS
Spray-Applied Membranes 60 mil - Liquid Boot®
Physical Properties of Liquid Boot® (spray-applied) Physical Property
*
* * *
Test Method
Result
ASTM D6392
Passed
ASTM D4068-88
Passed
City of Los Angeles
Passed
ASTM D1693-78
Passed
Soil Burial
ASTM E154-88
Passed
Elongation
ASTM D412
1,332% - Ø reinforcement, 90% recovery
Tensile Strength
ASTM D412
58 p.s.i. without reinforcement
Tensile Bond Strength to Concrete
ASTM D413
2,707 lbs/ft2 uplift force
Water Vapor Permeability
ASTM E96
0.24 perms
Water Vapor Transmission
ASTM E96
0.10 grains/h-ft2
Bonded Seam Strength Tests
Heat Aging- average tensile strength change, average tensile stress change, average elongation change, bonded seams
Dead Load Seam Strength
Environmental Stress-Cracking
* City of Los Angeles approval for 60-mil Liquid Boot® Gas Vapor Barrier
8
GAS VAPOR MITIGATION SYSTEMS
Chemical Properties of Liquid Boot® (spray-applied)
* * *
Chemical Property
Test Method
Result
Acid Exposure (10% H2SO4 for 90 days)
ASTM D543
Less than 1% weight change
Diesel (1000 mg/l), Ethylbenzene (1000 mg/l), Naphthalene (5000 mg/l) and Acetone (500 mg/l) Exposure for 7 days
ASTM D543
Less than 1% weight change, Less than 1% tensile strength change
Radon Permeability
Tested by US Dept. of Energy
Zero permeability to Radon (222Rn)
Micro Organism Resistance (Soil Burial)
ASTM D4068-88
Passed*
Methane Permeability
ASTM 1434-82
Passed*
Oil Resistance Test- average weight change, average tensile strength change, average tensile stress change, average elongation change, bonded seams, methane permeability
ASTM D543-87
Passed*
PCE Diffusion Coefficient
Tested at 6,000 mg/m3
2.74 x 10-14 m2/sec
TCE Diffusion Coefficient
mg/m3
8.04 x 10-14 m2/sec
Tested at 43,000 mg/m3
2.90 x 10-11 m2/sec
Benzene Diffusion Coefficient
Tested at 20,000
* City of Los Angeles approval for 60-mil Liquid Boot® Gas Vapor Barrier
9
GAS VAPOR MITIGATION SYSTEMS
Membrane Diffusion Test – Modified ASTM E96 The diagram illustrates how the diffusion coefficients on the Liquid Boot membrane for PCE, TCE and Benzene were determined CETCO R&D facility is capable of performing these tests
10
GAS VAPOR MITIGATION SYSTEMS
Fick’s Law Applying diffusion test data into the Fick’s Law equation results in the diffusion coefficient:
E= A(Csource - Cg0)Dczeff / Lcz where
11
E
=
Rate of mass transfer, g/s
A
=
Cross-sectional area through which vapors pass, cm2
Csource
=
Vapor concentration within the capillary zone, g/cm3-v
Cg0
=
A known vapor concentration at the top of the capillary zone, g/cm3-v (Cg0 is assumed to be zero as diffusion proceeds upward)
Dczeff
=
Effective diffusion coefficient across the capillary zone, cm2/s
Lcz
=
Thickness of capillary zone, cm
GAS VAPOR MITIGATION SYSTEMS
Diffusion Test Results Summary
12
Test Conditions
Average Solvent Diffusion Rate
Membrane Area
Membrane Thickness
Calculated Diffusion Coefficient
PCE Solvent @ 6,000 mg/m3
0.12 mg/day
1.45 x 10-2 m2
1.68 x 10-3 m
2.74 x 10-14 m2/sec
TCE Solvent @ 20,000 mg/m3
1.22 mg/day
1.48 x 10-2 m2
1.57 x 10-3 m
8.04 x 10-14 m2/sec
Benzene @ 13,000 mg/m3
1.4 mg/day
1.48 x 10-2 m2
1.57 x 10-3 m
1.4 x 10-14 m2/sec
Benzene @ 136,000 mg/m3
19 mg/day
1.48 x 10-2 m2
1.57 x 10-3 m
1.9 x 10-13 m2/sec
GAS VAPOR MITIGATION SYSTEMS
Venting Systems (Used In Conjunction with a Gas Vapor Barrier per ITRC Guidance) Passive Venting
Rely on nature pressure differentials to vent the subsurface gas Can be designed to be converted to active, if needed, to reduce vapor concentrations Should be properly designed to allow adequate flow of vapors Evaluation of air flow should be conducted
13
GAS VAPOR MITIGATION SYSTEMS
Active Venting Use of mechanical means to alter and maintain pressure gradients & redirect subsurface gas flow Major system components generally include gas extraction wells and piping, vacuum blowers, and gas/vapor treatment or reuse systems
CETCO SYSTEM OFFERINGS
14
GAS VAPOR MITIGATION SYSTEMS
CETCO System Offerings
Liquid Boot® Gas Vapor Barrier System
15
Liquid Boot® Plus
Coreflex®
High-Performance Gas Vapor Barrier System
Methane Barrier & Waterproofing System
GAS VAPOR MITIGATION SYSTEMS
GeoVent® Gas Venting System
LIQUID BOOT® GAS VAPOR BARRIER SYSTEM
16
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® System Description: Liquid Boot® is a cold, spray-applied membrane that acts as a gas vapor barrier and damp-proof membrane.
Typical Uses: Applied under slab and on below grade vertical walls as a gas vapor barrier to minimize vapor and nuisance water (non-hydrostatic conditions) migration into buildings Ideal for methane migration control Concrete water tank and reservoirs liner to prevent water seepage into concrete Applied as a liner to concrete canals for rehabilitation
Agency Approvals: City of Los Angeles Research Report # 24860 Approved for Liquid Boot®
Membrane for Gas Barrier
County of Los Angeles Department of Public Works Approved for “Liquid Boot® Application
as a Methane Gas Barrier”
NSF International-NSF/61
Approved for “Potable Water Tank Liner” for tanks >300,000 gallons
17
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® System Components and Features: GeoVentTM Gas Venting System Low profile; no trenching required
Liquid Boot® BaseFabric T-40/T-60 (fabric selection depends on site conditions) Heat bonded non-woven geotextile
Liquid Boot® Two component spray applied membrane (60 mils typical) Water based - No VOCs, odorless Bonds to most surfaces – eases detailing Seamless - eliminating membrane failures Rapid curing - reducing construction time High strength and elongation – durable
Liquid Boot® UltraShield Series Protection Course G Series - Needle-punched, nonwoven geotextile P Series - HDPE Polyethylene geomembrane Adheres to the underslab providing superior tensile strength
18
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® PILE CAPS AND FOOTINGS
PENETRATIONS
19
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® VERTICAL SURFACE ATTACHMENTS
20
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® TYPICAL SYSTEM INSTALLATION
1. Liquid Boot® applied to BaseFabric
21
GAS VAPOR MITIGATION SYSTEMS
2. Penetrations Detailed
3. UltraShield Protection Fabric
LIQUID BOOT® PLUS HIGH-PERFORMANCE GAS VAPOR BARRIER SYSTEM
22
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® Plus System Description: The Liquid Boot® Plus Gas Vapor Barrier system is a multi-layer and high-performance, cold spray-applied membrane that acts as a gas vapor barrier and damp-proof membrane.
Typical Uses: Installed under slab and on below grade vertical walls as a gas vapor barrier to minimize vapor and nuisance water (non-hydrostatic conditions) migration into buildings Ideal for applications with chlorinated solvents, BTEX and other PAHs
Agency Approvals: City of Los Angeles Research Report # 24860
Approved for Liquid Boot® Membrane for Gas Barrier County of Los Angeles Department of Public Works
Approved for “Liquid Boot® Application as a Methane Gas Barrier”
23
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® Plus System Components and Features: GeoVent® Gas Venting System
Low profile; no trenching required Liquid Boot® VI-20 Geomembrane
EVOH composite geomembrane - 20x lower VOC diffusion than 80 mil HDPE Liquid Boot® VI-20 Detailing Fabric Liquid Boot®
Two component spray applied membrane (60 mils typical) Water based - No VOCs, odorless Bonds to most surfaces – eases detailing Seamless - eliminating membrane failures Rapid curing - reducing construction time High strength and elongation - durable Liquid Boot® UltraShield Series Protection Course
G Series - Needle-punched, nonwoven geotextile P Series - HDPE Polyethylene geomembrane Adheres to the underslab providing superior tensile strength
24
GAS VAPOR MITIGATION SYSTEMS
Liquid Boot® VI-20 Geomembrane Tested by Dr. Kerry Rowe, Queens University, Ontario
Author of the POLLUTE model Well-known in geosynthetics industry Determined upper bound partition and diffusion coefficients Aqueous phase diffusion coefficient of co-extruded geomembrane
25
Liquid Boot® VI-20
80-mil HDPE
Contaminant
Diffusion Coefficient (m2/s)
Diffusion Coefficient (m2/s)
Benzene
9.0 x 10-15
3.5 x 10-13
Ethyl Benzene
8.0 x 10-15
1.8 x 10-13
Toluene
8.5 x 10-15
3.0 x 10-13
O-Xylene
7.5 x 10-15
1.5 x 10-13
GAS VAPOR MITIGATION SYSTEMS
EVOH Geomembrane Technology Liquid Boot® VI-20 geomembrane is a layer of EVOH between two layers of polyethylene. EVOH is a copolymer of:
Polyethylene (extrudes easily and improves bonding) Polyvinyl Alcohol and Ethylene Vinyl Alcohol (provides gas barrier)
Major applications for EVOH is in automotive fuel systems to control emissions of hydrocarbons The use of EVOH in a co-extrusion blow-molded tank with molecular weight HDPE originated in the US in response to mandates of VOC emissions reductions by the US EPA and the CA Air Resources Board (CARB) and is has been in widespread use globally for more than 15 years.
26
GAS VAPOR MITIGATION SYSTEMS
EVOH Geomembrane Technology Development started in 1989 in response to EPA and CARB mandates Emissions regulations have progressively become tighter each decade EVOH became barrier of choice due to VOC barrier properties Emissions through tank shell are
