EPA 510-R-97-002
SURVEY OF FLEXIBLE PIPING SYSTEMS
March 1997
ICF Incorporated
Fairfax, VA
BACKGROUND
For the purposes of this survey, a flexible pipeline is defined as a pipeline constructed of flexible
material that can be installed in single long runs without the necessity of regular joints either to extend
the length of the line or change directions. This material is usually shipped in rolls that are hundreds of
feet long, with the installer cutting lengths to fit the requirements of each installation. Most varieties of
flexible piping are available with secondary containment either as an option or an integral part of the
primary piping. In all cases, the secondary containment piping will not serve as primary piping. The
secondary containment piping is designed to channel leakage back to a sump or monitor point, where it
can be detected.
Because these pipelines differ significantly from the more traditional steel and fiberglass
reinforced plastic (FRP) pipelines, the U.S. Environmental Protection Agency (EPA) has periodically
requested a survey of their characteristics and availability. This is the third installment of this survey.1
METHODOLOGY
The survey was conducted by contacting flexible piping manufacturers that were identified
through a variety of sources of information, including previous surveys, trade journals, and industry
contacts.2 For the purposes of this review, a flexible piping manufacturer is defined as a company that
markets a flexible piping system (i.e., piping, fittings, joints, etc.). This includes companies that
manufacture one or more components of a flexible piping system but employ third party components
(e.g., piping manufactured by Furon Synflex) to complete their systems, as well as companies that
manufacture all of the components of their flexible piping system. Manufacturers included in this review
have pursued Underwriters Laboratories (UL) and/or Underwriters Laboratories of Canada (ULC)
listings for their products; however, it is possible that other manufacturers exist or that new piping
materials may enter the market in the future. Manufacturers and personnel contacted are listed in Table
1.
Information provided by manufacturers was not independently verified. A draft of this
document was submitted to survey respondents and Marcel Moreau Associates for technical review.
1 This survey is an update of the 1995 survey conducted by Marcel Moreau Associates and the 1993 survey
conducted by Ken Wilcox Associates.
2 ICF limited its search to up to nine public respondents, so as not to trigger requirements under the
Paperwork Reduction Act of 1980 for Office of Management and Budget clearance on surveys of 10 or more public
respondents.
1997 Flexible Piping Survey Page !
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Table 1. List of Manufacturers of Flexible Piping Systems Included in the Survey
Manufacturer
Advanced Polymer Technology, Inc.
Ameron Fiberglass Pipe Systems
Buffalo Environmental Products Corp.
Containment Technologies
Environ Products, Inc.
Titeflex Industrial Americas
Total Containment, Inc.
Western Fiberglass, Inc. (a.k.a. Western FG)
Contact
Bob Versaw
Reid Van Cleave
Glenn Eckart
Michael Nolan
Chris Ursillo
Bill Watkins
Randy Braun
Richard Lewis
Phone
616-759-9112
713-690-7777
410-553-0170
610-993-8140
610-594-0297
413-739-5631
610-666-7777
707-523-2050
Since 1995, one manufacturer of flexible piping systems, Smith Fiberglass Products, has chosen
to discontinue domestic sales of its flexible piping product, Smithflex. Another manufacturer, Buffalo
Environmental Products Corp., did not respond to requests for updated information. As a result, Buffalo
Environmental's product information in this survey (shown in italics) has not been updated from the
1995 survey. Two additional manufacturers (Titeflex Industrial Americas and Western Fiberglass) have
been included in this survey.3
RESULTS
An overview of flexible piping systems is presented in Tables 2 and 3 at the end of this Results
section. Table 2 describes key, parameters of available flexible piping systems, while Table 3 details
construction and compatibility information. Other specific information for individual manufacturers is
presented below:
Advanced Polymer Technology - (Polv-Tech)
*
*
All diameters of pipe are available in models for either pressure or suction pumping systems.
AH diameters of pipe are available in either coaxial secondarily contained or direct bury (single
walled) models.
Primary and secondary piping are installed as a single unit. The secondary pipe fits snugly
around the primary and contains small grooves parallel to the pipe axis to channel leakage to a
point where it can be detected.
3 Sources indicate that two additional manufacturers, Centron International, Inc., and S. Bravo Systems,
Inc., have also pursued UL 971 listings for their products. Through preliminary discussions with a Centron
representative, it became evident that Centron manufactures traditional rigid fiberglass piping rather than flexible
piping. S. Bravo Systems manufactures flexible piping systems, but representatives from S: Bravo did not respond
to requests for information. As a result, Centron International and S. Bravo Systems product information is not
included in this survey.
1997 Flexible Piping Survey
Page 2
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* The nylon 12 used as a liner for the primary pipe has been used by General Motors for the fuel
lines in its automobiles since 1980.
* Fittings used in this system are bolt-on compression fittings.
* All piping models incorporate a patented permeation barrier technology to reduce permeation to
very low levels.
* There is also a 3" diameter primary pipe that differs in construction from the smaller diameter
pipe construction listed in Table 3. The 3" diameter primary pipe is constructed of a modified
cross-linked polyacrylonitrile elastomer liner, permeation barriers, polyester braid, wire helix,
and nitrile cover. The secondary jacket on the 3" pipe is a tight-fitting sleeve comprised of
modified cross-linked polyacrylonitrile elastomer, polyester braid, and nitrile cover. There are
no flow channels in the secondary jacket of the 3" model. .
* Also available is a flexible product designed for vent lines and vapor recovery applications. The
product is available in 2" and 3" diameters, single wall or coaxial double wall. The 2" vent
piping is similar in construction to the 3" pressure piping, with the 3" vent piping being similar
in construction to the 3" pressure piping.
* A flexible, metallic-ducted (MD series) pipe is available for use in marina and above-ground
applications.
* UL listings for both primary and secondary pipe have been obtained on 1.5", 1.75", and 2"
piping. ULC listings for both primary and secondary pipe have been pbtained on 0.5", 0.75", 1",
1.5", 1.75", and 2" piping. ULC listings have also been obtained on system components such as
sumps, entry boots, etc.
Ameron Fiberglass Pipe Systems - (Dualoy 3000/FLXII and Dualoy 3000/FLX HI)
* Dualoy 3000/FLX I has been discontinued since the 1995 survey.
* The Dualoy 3000/FLX'systems (1.5" and 2") are UL listed for all fuels, including 100%
alcohols, for both primary and secondary piping.
* The Dualoy 3000/FLX systems (1.5" and 2") utilize a swaged on swivel coupling that allows for
1" of axial movement.
* The Dualoy 3000/FLX II (1.5" and 2") systems combine a flexible primary pipe with rigid
secondary fiberglass containment that is mechanically jointed.
* The Dualoy 3000/FLX HI (1.5" and 2") systems combine a primary flexible pipe with a coaxial
secondary jacket in one unit for direct burial.
* The Duaioy 3000/FLX primary systems (1.5" and 2") are UL listed for a 75 psi operating
pressure.
Buffalo Environmental Products Corp. - (Bufflex II)4
* Piping is available both in replaceable (primary piping slides in and out of secondary) and non-
replaceable (primary and secondary in intimate contact) varieties, all with smooth bores.
* The Nylon 11 liner (refer to Table 3) is used in primary piping that is to handle petroleum-based
fuels with 10% or less alcohol content. Kynar (a Teflon based material) is used in primary
piping that is to handle fuel blends with greater than 10% alcohol content.
* The Bufflex primary piping construction includes a double helix spring steel wire reinforcement
4 As noted on page 2, this information has not been updated from the 1995 survey.
1997 Flexible Piping Survey ! Page 3
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to provide flexibility without kinking. The piping construction greatly reduces stretching of the
piping when used with pressurized pumps and prevents collapse of the piping when used with
suction pumps.
* The secondary containment is smooth bore PVC reinforced with aPVC spiral member. There
are no corrugations to trap product or hinder insertion of the primary pipe.
* The replaceable type piping comes with a 30 year warranty and S2 million pollution liability
insurance coverage, provided the piping is properly installed and monitored. The non-
replaceable piping has a one year warranty and no accompanying insurance.
* The UL 971 Us ting for the primary pipe is pending, with acceptance expected by March 1, 1995.
Containment Technologies - (Perma-Flexx)
* The manufacturer prefers to call this product a pipe rather than a hose. This product can be used
for vent and vapor recovery piping because of its ability to lay flat and maintain its slope
underground.
* All diameters of pipe can be used for pressurized or suction pumping systems.
* All diameters of primary piping can be used in secondarily contained or single-wall (direct bury)
applications.
* The secondary piping is installed after the primary piping is already in place. The primary pipe
cannot be removed or replaced without excavation.
* Although only relatively recently introduced in North America, this piping technology has been
in use in Europe since 1981. Millions of feet of this product have been installed worldwide.
* The 10 year materials warranty applies when the piping is used with tank and dispenser sumps
manufactured by Containment Technologies.
* Perma-Flexx primary piping is UL listed, and both the primary and secondary piping is listed
with ULC, including MTBE blends.
Environ Products - (GeoFlex-S and GeoFlex-D)
* Earlier models of piping from this manufacturer include Flex I (single walled, direct bury), Flex
II (double walled), and Geoflex I (doubled-walled, for petroleum fuels only). Environ currently
manufactures GeoFlex-S (Single Wall) and GeoFlex-D (Double Wall) piping, a^ well as
GeoVent-S (Single Wall) vent piping.
* Environ offers piping in 0.75", 1.5", and 2" sizes for both pressure and suction systems. All
Environ GeoFlex and GeoVent piping is UL listed for petroleum, alcohols, and petroleum-
alcohol mixtures. 1.5" and 2" GeoFlex-D have listings for both the primary and secondary pipes.
3" GeoFlex is currently undergoing UL testing.
* 2" GeoVent-S piping has been tested by UL under vacuum conditions without failure.
* Environ also offers GeoDuct flexible ducting. This large diameter corrugated pipe permits
removal of either GeoFlex-S or GeoFlex-D without excavation.
* Environ offers the LDS Leak Detection System, which is a full secondary containment leak
detection system. The interstitial space of the GeoFlex-D piping and containment sumps can be
monitored using this leak detection system. The LDS Leak Detection System is UL 913 and
1238 listed for use in Class I—Division I~Group D hazardous locations. Third-party
confirmation that the LDS system meets EPA regulatory guidelines for automatic line leak
detectors is expected by April 1, 1997.
* Environ is testing with Underwriters Laboratories for "Coax" double wall fittings for use with
1997 Flexible Piping Survey Pa8e 4
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GeoFlex-D piping. These fittings provide full secondary containment and monitoring of the
fittings and riser pipe. Listing is expected in the Spring of 1997.
Installation of the GeoFlex piping system and an Environ manufactured or approved leak
detection system qualifies the installation for a 30 year warranty.
In addition to the Listings noted above, Environ currently has UL listings on flexible entry boots,
dispenser sumps, dispenser mounting frames, tank sumps, and tank sump mounting devices.
Titeflex Industrial Americas - (Prime/lex, Primeflex 20)
* Primeflex is constructed from 304 stainless steel wire braid with a flexible PTFE convoluted
innercore. End fittings are made from zinc plated carbon steel.
* Primeflex is designed to be used with both rigid and flexible secondary containment. It can be
installed in both new and existing installations with field attachable fittings. Fittings are
available in rigid, swivel, male, female, and flanged varieties.
* UL listing is pending on the Primeflex 20 piping.
Total Containment - (Enviroflex, Omniflex)
* Enviroflex primary piping is installed after the secondary is in place and can be removed and
replaced. Omniflex primary and secondary are installed as a single unit; the primary cannot be
removed from the secondary.
* First generation Enviroflex primary piping (yellow color) has been discontinued except for a 2.5"
pipe system for diesel fuel applications. Second generation Enviroflex primary piping (bone
color) is compatible with petroleum-based fuel and alcohol/petroleum blends up to 100% ethanol
or methanol.
* All diameters of pipe can be used for both pressurized and suction pumping systems.
* 1.5" and 2.5" primary pipe has a corrugated inner tube to provide flexibility without kinking.
* Total Containment also offers a 2.5 inch vent and vapor recovery pipe that is UL and ULC listed
and is compatible with petroleum-based fuels and alcohol/petroleum blends up to 100% ethanol
or methanol.
* HDPE tank and dispenser sumps, with penetration fittings, are available, carry a UL and ULC
listing, and are compatible with petroleum-based fuels and alcohol/petroleum blends up to 100%
ethanol or methanol.
* Total Containment offers a line of fiberglass tank and dispenser sumps. The fiberglass tank and
dispenser sumps are being prepared for submittal to UL and ULC for approval.
Western Fiberglass, Inc. - (Co-Flex)
* In addition to double-walled Co-Flex piping, Western also manufactures 2", 3", and 4" Stage II
Vapor/Vent/Remote Fill single wall pipe and 3", 4", and 6" Conduit/Chase triple containment
pipe. UL listed tank top, utility, vapor, transition, and dispenser mounting/containment
assemblies (sumps) are also available.
* Double-walled Co-Flex piping may be installed within a HDPE conduit/chase to achieve triple
containment.
* Co-Flex is supplied in 1000 foot reels or 200 foot boxes and is UV protected for outdoor storage.
1997 Flexible Piping Survey Page 5
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Cut lengths are available.
Western also manufactures clamp-on Direct Connection termination fittings that are placed on
the outside of the pipe and tightened with a torque wrench.
Piping products are suitable for suction or pressure systems.
1997 Flexible Piping Survey Page 6
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Table 2: Description of Available Flexible Piping Systems
Company
Advanced
Polymer
Technology
Ameron
-
Buffalo1
Containment
Technologies
Environ
Product
Poly-Tech
Dualoy
3000/FLX II
Dualoy
3000/FLX III
Bufflex II
Perma-Flexx
GeoFlex-S
GeoFlex-D
Diameter
(Inch)
.5, .75,1,
1.5, 1.75,
2,3
1.5
2.0
1.5
2.0
/, 1.5, 2
.75, 1.65,
2
.75, 1.5,
2, (3" -
Spr. '97)
First
Installation
May 1992
April 1995
June 1996
1989-90
March 1993
June 1992
Number of
Installations
2500 world
wide
(65-70% US)
70
50
300 (US)
700 (other)
1200
(75% North
America,
25% South
America)
Thousands
worldwide
Installer Training
on-site training
required for first
job, video training
aids available
on-site training
required for first
job. Classroom
training and slide
program also
available
on-site training
required for first job
training video;
onsite training is
optional
onsite training
required for first job
Minimum
Bend Radius
(Inches)
24 (1.5" pipe)
24
30
24
30
15
36
24
Test
Pressure:
Primary/
Secondary
60/1 Opsi
(1.5")
50/10-15psi
50/10-15psi
60/5-1 5 psi
60/5 psi
60/1 Opsi
Listing
UL971
ULC-ORD-
C107.14, 107.19,
107.21 (see text
for specific
listings)
UL971
UL971
ULC-ORD-
C107.4. 107.19,
107.21
UL971 (primary
only)
ULC-ORD-
C107.14, 107.19,
107.21
UL971
ULC-ORD-
C107.14, 107.19,
107.21
Materials
Warranty
1 0 years
1 0 years
1 0 years
30 years +
pollution
liability
insurance
10 years
1 0 years
30 year
system
NOTE: Only officially completed UL 971 listings are indicated in this table. UL listings are for primary and secondary piping unless otherwise noted.
ULC-ORD-C107.14 is at present an unpublished draft document.
1 Information not updated from the 1995 survey.
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Table 2, continued
Company
Titeflex
Industrial
Americas
Total
Containment
Western FG
Product
Primeflex
Primeflex 20
Enviroflex .
Omniflex
Co-Flex
Diameter
(Inch)
1.5,2.0
1.5,2.0
.5, .75, 1,
1.5,2.5
1.5
1.5
2.0
First
Installation
1993
Nov. '.989
June 1994
March 1995
Number of
Installations
10 (total)
7500 (US)
1600 (other)
950
Thousands
Installer Training
onsite training
onsite training
required for first job
onsite training
required for first
job, classroom
available
Minimum
Bend Radius
(Inches)
7.5
10
6 (1.5 primary)
or 12 (2.5
primary)
24 (secondary)
15 (primary)
24 (secondary)
24
30
Test
Pressure:
Primary/
Secondary
60psi
60psi
60/5-lOpsi
60/5-10psi
50/5-1 5 psi
Listing
UL97I (primary
only)
UL971 (pending
- primary only)
UL971
ULC-ORD-
C 107.4, 107.19,
107.21
UL971
ULC-ORD-
C 107.4, 107.7,
107.19
UL971
ULC-ORD-
C107.14, 107.19
Materials
Warranty
1 year
20 years
1 0 years
1 0 years
NOTE: Only officially completed UL 971 listings are indicated in this table. UL listings are for primary and secondary piping unless otherwise noted.
ULC-ORD-C107.14 is at present an unpublished draft document.
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Table 3: Construction and Compatibility of Flexible Piping Systems
Company
Advanced Polymer
Technology
Ameron
Buffalo1
Containment
Technologies
Environ
Product
Poly-Tech
Dualoy 3000/FLX II
Dualoy 3000/FLX III
Bufflex 11
Perma-Flexx
Geoflex-S & -D
Primary Pipe Construction
(Inside to Outside)
-Nylon 12 liner
- proprietary permeation barrier
- Nylon 6 braid
- polyethylene cover
- fluoroplastic liner
- nylon/nylon braid
- fluoroplastic liner
- nylon/nylon braid
-Nylon 11 or Kynar
- polyester yarn braiding
- polyurethane
- double helix spring steel wire
- polyurethane
- nylon (Dupont Selar)
- polyethylene
- proprietary permeation barrier
- flexible structural filler layer
- braided fiber reinforcement
- thermoplastic
Primary Pipe
Compatibility
petroleum, alcohols,
MTBE
petroleum, alcohols,
MTBE
petroleum, alcohols,
MTBE
petroleum, alcohols
petroleum, alcohols,
MTBE
petroleum, alcohols,
MTBE
Secondary Pipe
Construction
(Inside to Outside)
- polyethylene
- permeation barrier
- polyethylene
FLX II:
- resin rich liner
- epoxy resin
- glass fiber
- epoxy resin
FLX HI:
-polyethlene
- polyvinylchloride (PVC)
- polyethylene
- polyethylene
- proprietary tie layer
- nylon
Secondary Pipe
Compatibility
petroleum, alcohols,
MTBE
petroleum, alcohols
petroleum, alcohols
petroleum, alcohols,
MTBE
petroleum, alcohols,
MTBE
Information not updated from the 1995 survey.
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Table 3, continued
Company
Titeflex Industrial
Americas
Total Containment
Western FG
Product
Primeflex
Primeflex 20
Enviroflex
Omniflex
Co-Flex
Primary Pipe Construction
(Inside to Outside)
- PTFE Teflon-impregnated
fiberglass
- stainless steel braid
- PTFE Teflon impregnated
fiberglass
-PPS
- proprietary inner tube
- reinforcing braid
- polyethylene
-PVDF
- inner liner-Urethane-Polyester
reinforcement braid-jacket
Primary Pipe
Compatibility
petroleum, alcohols,
MTBE
petroleum, alcohols,
MTBE
petroleum, alcohols,
MTBE
Secondary Pipe
Construction
(Inside to Outside)
None
-polyethylene
- polyethylene
Secondary Pipe
Compatibility
N/A
petroleum, alcohols,
MTBE (Enviroflex only)
petroleum, alcohols,
MTBE
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ADDITIONAL ITEMS OF INTEREST
Underwriters Laboratories. Inc. CUD Listings
Nonmetallic petroleum piping systems are currently evaluated using UL Standard 971,
"Nonmetallic Underground Piping for Flammable Liquids." The focus of the standard is nonmetallic
primary and secondary rigid petroleum piping (i.e., fiberglass). However, the standard contains
provisions that apply to flexible piping. Some of the major tests for flexible piping include: a sustained
pressure test; a leakage test; immersion tests; an air oven aging test; and a permeability test. For a more
complete description of the tests applying to flexible piping in UL 971, please refer to Appendix A of
this survey. A discussion of the Underwriters Laboratories of Canada (ULC) standards for flexible
piping is also included in Appendix A.
UL is currently developing and revising the UL standards for underground piping systems and
related categories. UL plans to formally incorporate specific requirements for flexible piping into UL
971 in 1997. In addition, UL has developed a listing program for vapor recovery pipe and vent pipe. If
there is sufficient interest, UL will incorporate provisions for vapor recovery and vent pipe into UL 971
or a separate standard.5
Underwriters Laboratories of Canada (ULC) Listings
UL has a parallel organization in Canada known as Underwriters' Laboratories of Canada
(ULC). In response to the need to evaluate flexible piping systems for use in Canada, ULC has
developed what it calls "Other Recognized Documents" or "ORD." These documents describe a specific
series of tests that are used to evaluate a product. These documents are developed within ULC and are
reviewed by other inspection agencies, but have not undergone the rigorous outside committee review
process required for a ULC Standard. ULC has developed the following three ORD's to evaluate
flexible piping systems:
ULC/ORD-C107.4-19,92 Ducted Flexible Underground Piping Systems for Flammable
and Combustible Liquids
ULC/ORD-C 107.19-1992 Secondary Containment of Underground Piping for Flammable
and Combustible Liquids
ULC/ORD-C 107.21 -1992 Under Dispenser Sumps
In addition, ULC is developing a draft ORD (C107.14) intended to evaluate flexible piping
systems which are to be directly buried. For more information on this draft ORD, refer to Appendix A of
this survey.
Methyl Tertiary Butyl Ether (MTBE)
Although MTBE has been used as a blending component of gasoline since 1979, only in recent
years has MTBE become widely used to raise the oxygen content of gasoline. This is primarily due to
EPA requiring the use of oxygenated gasoline in many cities during the winter and summer months to
5 UL 971: An Evaluation of Flexible Piping, Petroleum Equipment and Technology, July/August 1996.
1997 Flexible Piping Survey Page 11
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reduce carbon monoxide pollution.6 Because of the increase in use of MTBE, at least seven of the
flexible piping manufacturers included in this survey have tested their products for compatibility with
MTBE.7 Currently, MTBE is not designated as an official testing liquid in the UL 971 testing process.
However, several manufacturers have requested and received UL and/or ULC testing for MTBE.
Realize, however, that UL/ULC testing for MTBE does not imply that a particular product has undergone
more rigorous testing and evaluation than a product that has been manufacturer tested. Table 4
summarizes the MTBE testing that each manufacturer has pursued to date.
Table 4. MTBE Testing Performed on Flexible Piping Systems To-Date
Manufacturer and Product
Advanced Polymer Technology (Poly-
Tech)
Ameron (Dualoy 3000/FLX II & 3)
Buffalo (Bufflex II)
Containment Technologies (Perma-Flexx)
Environ (GeoFlex-S & GeoFlex-D)
Titeflex Industrial Americas (Primeflex &
Primeflex 20)
Total Containment (Enviroflex &
Omniflex)
Western FG (Co-Flex)
Testing Performed
ULC Testing -- Primary and Secondary Piping
Manufacturer Testing — Primary Piping
Unknown
UL Testing — Primary Piping, ULC Testing —
Secondary Piping
Primary and
UL Testing — Primary and Secondary Piping
Manufacturer Testing — Primary Piping
ULC Testing — Primary and Secondary Piping (both products),
UL Testing — Secondary Piping (Enviroflex only)
UL Testing -- Primary and Secondary Piping
Compatibility and Permeability
Compatibility and permeability are important characteristics of flexible piping systems, but the
terms are often confused. Compatibility is the ability of a material to retain its physical properties when
exposed to another substance. Permeability is a measure of the amount of a substance that migrates
through a material over a given time period.
For example, polyethylene is compatible with petroleum products. This means that it does not
significantly dissolve, degrade, or fall apart when in contact with petroleum products. However,
polyethylene is relatively permeable to petroleum products. This means that the liquid level in a tightly
sealed polyethylene container filled with gasoline would slowly decrease over time as gasoline
molecules migrate through the walls of the container. A study sponsored by a fiberglass piping
manufacturer indicated that a sample of corrugated polyethylene secondary containment piping filled
6 Information obtained from www.chevron.com/prodserv/gas_q&a/mtbe.htrnl.
7 It is unclear as to whether Buffalo Environmental has performed product testing for MTBE, because they
did not provide an update on their products.
1997 Flexible Piping Survey
Page 12
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with gasoline lost 39% of its weight over a period of 181 days (undated, untitled sales brochure by
Ameron Fiberglass Pipe Systems).
Constructing flexible petroleum piping that is compatible with petroleum and alcohol liquids is
relatively easy. The most challenging aspect of constructing a flexible piping system has proven to be
meeting the permeation standard of no more than one percent loss of liquid over a 180 day period that is
used by both UL and ULC for primary piping. UL uses this same permeation test for secondary piping.
The ULC ORD for secondary piping includes evaluations of compatibility but does not evaluate the
permeability of the secondary piping.
CONCLUSIONS
Flexible piping technology has come into widespread use for dispensing motor fuels. Since
1995, the flexible piping industry has seen an approximately 50 percent increase in the number of system
installations. With the increasing use of MTBE, several flexible piping manufacturers have performed
product testing for MTBE, and some manufacturers have requested and received UL and/or ULC testing
for MTBE. To date, problems with flexible piping systems have been limited to fungal decay of first
generation polyurethane coated piping. The fungal decay is mostly cosmetic and does not cause product
failure, however, one manufacturer (Total Containment) has changed its outer layer construction to
polyethylene and is in the process of replacing the polyurethane piping. Most manufacturers are now
marketing third and fourth generation products. Problems with these systems have been infrequent, and
manufacturers have stood by their products. From an environmental protection standpoint, the
performance of this technology to date has been excellent.
1997 Flexible Piping Survey Page 13
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APPENDIX A
ADDITIONAL INFORMATION ON UL AND ULC LISTINGS AND UL 971
TEST REQUIREMENTS FOR FLEXIBLE PIPE
UNDERWRITERS LABORATORIES, INC. (UL) LISTINGS
Underwriters Laboratories in the United States has been the primary testing organization for
underground petroleum piping systems. When a new product is presented to UL for testing, UL
personnel review the product and determine a testing program. If demand warrants, the testing program
may become more formally defined as a UL "Subject," which often serves as a preliminary "Standard."
A UL "Standard" is created by review and evaluation of a "Subject" by interested parties to create a
consensus document which is recognized as an "American National Standard" by the American National
Standards Institute (ANSI).
Flexible piping is currently evaluated under UL Standard 971. Table A-l presents a summary of
the major test requirements required to obtain a UL 971 listing.
UNDERWRITERS' LABORATORIES OF CANADA (ULC) LISTINGS
Underwriters Laboratories of Canada is developing a draft ORD (C107.14) intended to evaluate
flexible piping systems which are to be directly buried. In ULC terminology, secondarily contained
ducted piping is the type where small diameter primary pipe (typically 1.5 or 2 inch) is installed inside a
larger diameter (typically 4 inch) outer pipe. C 107.4 is the appropriate ORD for ducted flexible piping.
The C107.14 test protocol is also intended to test any single walled flexible piping buried directly in the
ground. Although several manufacturers have had their products tested according to the proposed
C107.14 test protocol, the document is still in draft form and could not be reviewed for this survey.
C107.14 differs from C107.4 in that it includes the following additional tests: accelerated light and water
test, low temperature drop test'(-40°C), low temperature impact resistance test (-40°C), room
temperature impact resistance, cyclic operation test (1,000 cycles at 50 psi), crush strength test, flattening
test, burst strength test (650 psi) and an identification test.
READING A UL OR ULC LABEL
AH products that have achieved a UL 971 or a ULC/ORD-C 107.4 listing are not created equal. It
is important to recognize that within each evaluation there are variables that a manufacturer can select,
such as type of liquid for which the product is intended. For example, both UL and ULC listings may be
for "petroleum products only" or for "petroleum products, alcohols, and alcohol-gasoline mixtures."
These variables will be reflected only on the actual label that is affixed to the product. In other words, a
UL 971 or ULC 107.4 listing does not automatically imply that a product is suitable for use with alcohol
fuels. Alcohol compatibility and other qualifying statements can be determined only be reading the UL
or ULC label affixed to the product.
Both UL and ULC listings are for "underground" piping. This means that it is assumed that the
piping will be buried and not subject to fire exposure. Unless specifically tested for fire exposure, the
UL and ULC listings for flexible piping do not apply to portions of flexible pipe that are exposed in
underground sumps.
1997 Flexible Piping Survey Page A-l
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Table A-l. UL 971 Test Requirements
Test
Permeability
Air Oven Aging
Leakage
Hydrostatic Strength
Cyclic Pressure
Immersion
Requirements
Samples of primary and secondary pipe filled with representative liquids for
1 80 days shall not exhibit a rate of permeation greater than 4 g/nr/day for
primary piping and 24 g/nr/day for secondary piping.
Samples of primary and secondary pipe and fittings shall be subjected to air
oven aging at 70°C (158°F) for 30, 90, and 180 days. Samples shall then be
subjected to a crush-strength test, an apparent tensile-strength test, and an
adhesive shear strength test. Samples exposed to air oven aging shall retain
80 percent of the physical properties of a sample not exposed to air oven
aging.
Samples of primary and secondary piping shall not leak when they are
subjected to a hydrostatic pressure of two times the maximum rated pressure
for a period of five minutes.
Samples of primary piping shall not leak or be damaged when subjected to a
hydrostatic pressure of five times the maximum rated pressure for a period of
one minute.
Samples of primary piping and fittings shall not be damaged or leak when
subjected to cyclic pressure conditions in accordance with ASTM D2 143-69
(1987).
Samples of primary and secondary piping will be immersed in Type A test
liquids for 30, 90, 180, and 270 days and Type B test liquids for 30, 90, and
180 days. Samples of primary piping that have been immersed for 270 days
• in Type A liquids shall retain 50 percent of their properties, and samples of
primary piping that have been immersed for 180 days in Type B liquids shall
retain 30 percent of their properties. Samples of secondary piping that have
been immersed for 270 days in Type A liquids shall retain 50 percent of their
properties, and samples of secondary piping that has been immersed for 30
days in internal and 180 days in external Type B liquids shall retain 30
percent of their original properties. Systems of pipe and fittings shall undergo
analogous testing.
Additional Tests for Primary and Secondary Piping: Torque Test, Bending-Moment Test, Bending
Test, Drop-Test, Low-Temperature Drop Test, Ball-Impact Test, Low-Temperature Ball-Impact Test,
and Crush-Strength Test.
1997 Flexible Piping Survey
Page A-2
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